Search tips
Search criteria

Results 1-25 (2049042)

Clipboard (0)

Related Articles

1.  Validation of a Microsphere Immunoassay for Serological Leptospirosis Diagnosis in Human Serum by Comparison to the Current Gold Standard 
PLoS Neglected Tropical Diseases  2015;9(3):e0003636.
A microsphere immunoassay (MIA) utilising Luminex xMap technology that is capable of determining leptospirosis IgG and IgM independently was developed. The MIA was validated using 200 human samples submitted for routine leptospirosis serology testing. The traditional microscopic agglutination (MAT) method (now 100 years old) suffers from a significant range of technical problems including a dependence on antisera which is difficult to source and produce, false positive reactions due to auto-agglutination and an inability to differentiate between IgG and IgM antibodies. A comparative validation method of the MIA against the MAT was performed and used to determine the ability of the MIA to detect leptospiral antibodies when compared with the MAT. The assay was able to determine samples in the reactive, equivocal and non-reactive ranges when compared to the MAT and was able to differentiate leptospiral IgG antibodies from leptospiral IgM antibodies. The MIA is more sensitive than the MAT and in true infections was able to detect low levels of antibody in the later stages of the acute phase as well as detect higher levels of IgM antibody earlier in the immune phase of the infection. The relatively low cost, high throughput platform and significantly reduced dependency on large volumes of rabbit antisera make this assay worthy of consideration for any microbiological assay that currently uses agglutination assays.
Author Summary
Leptospirosis is a zoonotic disease caused by spirochaetes of the genus Leptospira and affects millions of people, worldwide, each year. Laboratory diagnosis of leptospirosis currently relies on methods that are flawed in many areas. Current methods are outdated, time consuming and expensive. They rely on a continuous supply of animal products (rabbit anti-sera) and require specialist expertise and equipment. The current gold standard diagnostic assay for leptospirosis (MAT) cannot determine IgG from IgM antibodies and relies on live cultures, which presents problems in the way of maintenance and attenuation. Development of a new diagnostic assay for serological diagnosis of leptospirosis that is specific, sensitive and able to discriminate between IgG and IgM classes of antibodies—as well as being more cost effective—will significantly improve the capabilities for detecting leptospirosis infections. It will provide medical professionals with more valuable diagnostic information and public health professionals with improved epidemiological information.
PMCID: PMC4373873  PMID: 25807009
2.  Methods for Detection of West Nile Virus Antibodies In Mosquito Blood Meals 
We describe and compare 2 qualitative serologic techniques for detecting West Nile virus (WNV)-specific antibodies in mosquito blood meals. The techniques are the biotin microsphere immunoassay (b-MIA) and the inhibition platform of the VectorTest™ WNV antigen assay (VecTest-inhibition). To demonstrate the ability of these tests to detect WNV-neutralizing antibodies, we experimentally exposed feeding mosquitoes to blood containing 5 concentrations of 6B6C-1, a flavivirus-neutralizing monoclonal antibody. Antibody concentrations were quantified using the 90% plaque-reduction neutralization test (PRNT90). After 24 h of blood-meal digestion at 22.5°C, the threshold PRNT90 titer of detection was ≤18 for b-MIA and ≤50 for VecTest-inhibition. Both tests reliably detected antibodies in 3 of 3 blood meals that had been digested for up to 30 h, or were about 25% digested. The b-MIA was also applied to mosquitoes that had engorged on avian blood in Arizona following a WNV epidemic in 2010. There was no significant difference in the WNV antibody prevalence determined by b-MIA (52% of 71 avian blood meals) compared to the WNV-neutralizing antibody prevalence in birds determined by direct sampling (49% of 234 birds). VecTest-inhibition requires fewer resources and may be used in the field without a laboratory, but consumes the entire blood meal and relies on subjective interpretation of results. The b-MIA requires a laboratory and sophisticated equipment and reagents. Results for b-MIA are analyzed objectively and can be applied to mosquito blood meals with greater confidence than the VecTest-inhibition method and thus can contribute substantially to research and surveillance programs that would benefit from the detection of specific WNV antibodies in mosquito blood meals.
PMCID: PMC4785996  PMID: 25843170
Mosquito; blood meal; antibody; West Nile virus; surveillance
3.  AB106. Differential regulation of LncRNA-SARCC suppresses VHL-mutant RCC cell proliferation yet promotes VHL-normal RCC cell proliferation via modulating androgen receptor/HIF-2α/C-MYC axis under hypoxia 
Translational Andrology and Urology  2016;5(Suppl 1):AB106.
It is well established that hypoxia contributes to tumor progression in a HIF-2α-dependent manner in renal cell carcinoma (RCC), yet the role of LncRNAs involved in hypoxia-mediated RCC progression remains unclear. Here we demonstrate that LncRNA-SARCC is differentially regulated by hypoxia in a VHL-dependent manner both in tissue culture and in human RCC clinical samples. LncRNA-SARCC can suppress hypoxic cell cycle progression in the VHL-mutant RCC cells while derepress it in the VHL-restored RCC cells. Mechanism dissection reveals that LncRNA-SARCC can post-transcriptionally regulate androgen receptor (AR) by physically binding and destabilizing AR protein to suppress AR/HIF-2α/C-MYC signals. In return, HIF-2α can transcriptionally regulate the LncRNA-SARCC expression via binding to hypoxia responsive elements (HREs) on the promoter of LncRNA-SARCC. The negative feedback modulation between LncRNA-SARCC/AR complex and HIF-2α signaling may then lead to differentially modulate RCC progression in a VHL-dependent manner. Together, these results may provide us a new therapeutic approach via targeting this newly identified signal from LncRNA-SARCC to AR-mediated HIF-2α/C-MYC signals against RCC progression.
Human samples—surgical specimens from human ccRCC tissues were obtained from 16 patients in the Department of Urology, Shanghai Tenth People’s Hospital, Tongji Medical School (Shanghai, China), freshly frozen in liquid nitrogen and stored at −80 °C until use. OCT-embedded blocks were sectioned until cut planes were >70% tumor. Sections were collected for DNA, RNA, and protein extraction. Samples were cataloged, clinical information on cases was obtained through chart review, and patient identifiers were removed before analysis. Informed consent was obtained from patients and the study was approved by the Institutional Review Board of Tongji Medical College. Immunohistochemistry—immunohistochemical staining was performed as previously described [40], with antibodies specific for HIF-1α, HIF-2α, C-MYC, Ki-67, AR (Abcam Inc., Cambridge, MA, USA; 1:200 dilution) and CAIX (Santa Cruz Biotechnology, Santa Cruz, CA, USA; 1:200 dilution). The reactivity degree was assessed by at least two pathologists without knowledge of the clinicopathological features of tumors. The degree of positivity was initially classified according to the percentage of positive tumor cells as the following: (−) >5% cells positive, (1+) 6–25% cells positive, (2+) 26–50% cells positive, and (3+) >50% cells positive. For AR, HIF-1α, HIF-2α, C-MYC, Ki-67 and CAIX, samples were scored as negative/weak, intermediate, or strong. Only cells with clear tumor cell morphology were scored. Cell culture and transfection—the human VHL-mut RCC cell lines SW839 (AR positive), OSRC-2 (AR positive), A498 (AR negative), 769-P (AR negative), 786-O (AR negative), and the human VHL-wt RCC cell lines Caki-1 (AR positive), Caki-2 (AR positive), and the immortalized proximal tubule epithelial cell line from normal adult human kidney HK-2 and 293T (AR positive) were originally purchased from American Type Culture Collection (ATCC, Manassas, VA, USA) and preserved in our lab. All RCC cells were cultured in DMEM medium (Invitrogen, Carlsbad, CA, USA) supplemented with 10% fetal bovine serum (FBS) in the humidified 5% CO2 environment at 37 °C. SW839-VHL cell lines were stably transfected with VHL-wt cDNA into VHL-mut SW839 cells (ATCC). To generate LncRNA-SARCC overexpressing or LncRNA-SARCC knocked-down stable clones of SW839, SW839-VHL and OSRC-2 cells were transfected with lentiviral vectors, pWPI-LncRNA-SARCC vs. pWPI-Vec or pLKO1-sh-LncRNA-SARCC vs. pLKO1-shRNA-control, with the PAX2 packaging plasmid, and PMD2G envelope plasmid, then transfected into 293T cells for 48 hours to obtain the lentivirus soup followed by cryopreservation in −80 °C for later use. The cells were transfected using the lipofectamine 3000 (Invitrogen) reverse transfection protocol, according to the manufacturer’s instructions. Hypoxia—hypoxia (0.5% O2, 5% CO2, 94.5% N2) was achieved using an In Vivo2 hypoxic workstation (Ruskinn Technologies) or in a positive pressure chamber receiving gas from a custom-mixed tank (Airgas). Oxyrase® (Oxyrase) was used as a hypoxia mimetic at a final concentration of 100 mM while CoCl2 was used as a hypoxia mimetic at a final concentration of 200 µM. RNA immunoprecipitation (RIP)—native RIP was performed as described previously [50]. Briefly, SW839, SW839-VHL and OSRC-2 cells were lysed in RIPA lysis buffer (20 mM Tris-HCl/pH 7.5, 150 mM NaCl, 1 mM Na2EDTA, 1 mM EGTA, 1% NP-40, 1% sodium deoxycholate, 2.5 mM sodium pyrophosphate, 1 mM beta-glycerophosphate, 1 mM Na3VO4, 1 µg/mL leupeptin) supplemented with RNase inhibitor, protease inhibitor cocktail. RNase-free DNase (NEB) (400 U) was then added to the lysates and incubated on-ice for 30 minutes. The cell lysates were diluted in the RIPA buffer and 50 µL of the supernatant saved as input for PCR analysis. A total of 500 µL of the supernatant was incubated with 4 µg of AR antibody overnight (normal rabbit IgG as control). Protein A/G beads were pre-blocked by 15 mg/mL BSA in PBS. Then pre-blocked beads were added to the antibody-lysate mixture and incubated for another 2 hours. The RNA/antibody complex was washed four times by RIPA buffer supplemented with RNase inhibitor, protease inhibitor cocktail. The RNA was extracted using Trizol (Invitrogen) according to the manufacturer’s protocol and subjected to RT-qPCR analysis. For UV cross-linking and RIP, cells were first subjected to formaldehyde cross-linking and then native RIP protocol was conducted. RNA-pull down assay—LncRNA-SARCC, LncRNA-SARCC (1.6 kb), LncRNA-SARCC (1.2 kb) or LncRNA-SARCC (0.8 kb) were in vitro transcribed respectively from the PCR generated T7 promoter driven DNA fragments and biotin-labeled with the Biotin RNA Labeling Mix (Roche) and T7 RNA polymerase (Roche), treated with RNase-free DNase I (Roche), and purified with an RNeasy Mini Kit (Qiagen, Valencia, CA, USA). One milligram of whole-cell lysates from SW839 cells were incubated with 3 µg of purified biotinylated transcripts for 1 hour at 25 °C and complexes were isolated with streptavidin agarose beads (Invitrogen). The AR protein present in the pull-down material was detected by standard immunoblot analysis. Chromatin immunoprecipitation assay (ChIP)—cells were cross-linked with 4% formaldehyde for 10 minutes followed by cell collection and sonication with a predetermined power to yield genomic DNA fragments of 300–1,000 bp long. Lysates were precleared sequentially with normal rabbit IgG (sc-2027, Santa Cruz Biotechnology) and protein A-agarose. Anti-AR antibody (2.0 µg) was added to the cell lysates and incubated at 4 °C overnight. For the negative control, IgG was used in the reaction. Cell-cycle analysis—cells were plated at a density such that they would be 50% confluent on the day of analysis. Treatment (hypoxia) was then initiated over the next several days, so that all cells were in culture for the same amount of time and at similar confluency when harvested. BrdU analysis was performed following the standard protocol (Becton Dickinson) after a 20 min pulse with 10 mM BrdU. Cells were stained with Alexa 488 anti-BrdU (Invitrogen) and 0.1 M propidium iodide and analyzed in an LSR FACS machine (Becton Dickinson). For proliferation analysis with Hoechst staining, 104 cells were plated on 6-cm2 plates, with staining and counting done according to the manufacturer’s instructions (Invitrogen). Luciferase assay—cells were plated in 24-well plates and transfected with pGL3 reporter constructs using lipofectamine (Invitrogen) according to the manufacturer’s instruction. After transfection, DMEM media was added into the culture with dihydrotestosterone (DHT) with ethanol as vehicle control. pRL-TK was used as internal control. Luciferase activity was measured by Dual-Luciferase Assay (Promega) according to the manufacturer’s manual. Subcutaneous and renal capsule implantation—SW839 cells expressing pLKO1-sh-LncRNA-SARCC vs. pLKO1-shRNA-control (2×106) and SW839-VHL cells expressing pWPI-LncRNA-SARCC vs. pWPI-mock (2×106), were subcutaneously injected into one flank of 6-week-old male athymic nude mice (NCI) (n=8 mice per group). After 8–9 weeks, mice were sacrificed, and tumors were excised and weighed. Similarly, cells were injected into left renal capsule of 6-week-old male athymic nude mice (NCI) (n=8 mice per group). After 7–8 weeks, mice were sacrificed, and tumors were excised and weighed. Studies on animals were conducted with approval from the Animal Research Ethics Committee of the University of Rochester Medical Center. Statistical analysis—unless otherwise stated, all data were shown as mean ± SD. The SPSS 12.0 statistical software (SPSS Inc., Chicago, IL, USA) was applied for statistical analysis. The χ2 analysis and Fisher exact probability analysis were applied for comparison among the expression of AR, HIF-1α, HIF-2α, C-MYC and Ki-67 and individual clinicopathological features. Difference of tumor cells was determined by t test or analysis of variance.
(I) Hypoxia differentially regulates RCC cell proliferation in a VHL-dependent manner; (II) LncRNA-SARCC is differentially modulated by hypoxia in a VHL-dependent manner and is physically associated with AR; (III) LncRNA-SARCC interacts with AR and decreases AR protein stability; (IV) LncRNA-SARCC suppressed AR which alters HIF-2α/C-MYC signals under hypoxia; (V) mechanism dissection how AR modulates HIF-2α expression at the transcriptional level under hypoxia; (VI) mechanism dissection how HIF-2α modulates LncRNA-SARCC expression at the transcriptional level under hypoxia; (VII) LncRNA-SARCC differentially modulates RCC proliferation under hypoxia in the RCC in vivo mouse model.
LncRNA-SARCC is differentially regulated by hypoxia in a VHL-dependent manner both in tissue culture and in human RCC clinical samples. LncRNA-SARCC can suppress hypoxic cell cycle progression in the VHL-mutant RCC cells while derepress it in the VHL-restored RCC cells.
PMCID: PMC4842606
Renal cell carcinoma; LncRNA; hypoxia; androgen receptor
4.  Effect of Serum Heat-Inactivation and Dilution on Detection of Anti-WNV Antibodies in Mice by West Nile Virus E-protein Microsphere Immunoassay 
PLoS ONE  2012;7(9):e45851.
Immunopathogenesis studies employing West Nile virus (WNV) mice model are important for the development of antivirals and vaccines against WNV. Since antibodies produced in mice early during WNV infection are essential for clearing virus from the periphery, it is important to detect early and persistent anti-WNV antibodies. ELISA and plaque reduction neutralization tests are traditionally used for detection of anti-WNV antibodies and WNV-neutralizing antibodies, respectively. Although these assays are sensitive and specific, they are expensive and time consuming. Microsphere immunoassays (MIA) are sensitive, specific, allow for high throughput, are cost effective, require less time to perform than other methods, and require low serum volumes. Several assay parameters such as serum heat-inactivation (HI) and dilution can alter WNV MIA sensitivity. We examined the effect of these parameters on WNV E-protein MIA (WNV E-MIA) for the enhanced detection of anti-WNV IgM and IgG antibodies. WNV E-MIA was conducted using serial dilutions of HI and non-HI (NHI) serum collected at various time points from mice inoculated with WNV. HI significantly enhanced detection of IgM and IgG antibodies as compared to NHI serum. WNV IgM and IgG antibodies in HI sera were detected earlier at day 3 and IgM antibodies persisted up to day 24 after infection. HI serum at 1∶20 dilution was found to be optimal for detection of both IgM and IgG antibodies as compared to higher-serum dilutions. Further, addition of exogenous complement to the HI serum decreased the WNV E-MIA sensitivity. These results suggest that serum-HI and optimal dilution enhance WNV E-MIA sensitivity by eliminating the complement interference, thereby detecting low-titer anti-WNV antibodies during early and late phases of infection. This improved MIA can also be readily employed for detection of low-titer antibodies for detection of other infectious agents and host proteins.
PMCID: PMC3457982  PMID: 23049879
5.  NeutrAvidin Functionalization of CdSe/CdS Quantum Nanorods and Quantification of Biotin Binding Sites using Biotin-4-Fluorescein Fluorescence Quenching 
Bioconjugate chemistry  2016;27(3):562-568.
We developed methods to solubilize, coat, and functionalize with NeutrAvidin elongated semiconductor nanocrystals (quantum nanorods, QRs) for use in single molecule polarized fluorescence microscopy. Three different ligands were compared with regard to efficacy for attaching NeutrAvidin using the “zero-length cross-linker” 1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide (EDC). Biotin-4-fluorescene (B4F), a fluorophore that is quenched when bound to avidin proteins, was used to quantify biotin binding activity of the NeutrAvidin coated QRs and biotin binding activity of commercially available streptavidin coated quantum dots (QDs). All three coating methods produced QRs with NeutrAvidin coating density comparable to the streptavidin coating density of the commercially available quantum dots (QDs) in the B4F assay. One type of QD available from the supplier (ITK QDs) exhibited ~5-fold higher streptavidin surface density compared to our QRs, whereas the other type of QD (PEG QDs) had 5-fold lower density. The number of streptavidins per QD increased from ~7 streptavidin tetramers for the smallest QDs emitting fluorescence at 525 nm (QD525) to ~20 tetramers for larger, longer wavelength QDs (QD655, QD705, and QD800). QRs coated with NeutrAvidin using mercaptoundecanoicacid (MUA) and QDs coated with streptavidin bound to biotinylated cytoplasmic dynein in single molecule TIRF microscopy assays, whereas Poly(maleic anhydride-alt-1-ocatdecene) (PMAOD) or glutathione (GSH) QRs did not bind cytoplasmic dynein. The coating methods require optimization of conditions and concentrations to balance between substantial NeutrAvidin binding vs tendency of QRs to aggregate and degrade over time.
Graphical abstract
PMCID: PMC5124603  PMID: 26722835
6.  Effects of lorglumide on growth and invasion of human pancreatic cancer cell line Mia PaCa-2 in vitro through the cholecystokinin-cholecystokinin-1 receptor pathway 
Background: Cholecystokinin (CCK) has been found to be a growth stimulant through its special receptor pathway, especially for gastrointestinal malignancies. Although the CCK-1 receptor has been shown to be highly expressed in resected human pancreatic cancer samples, its role is less clear.
Objective: The aim of this in vitro study was to investigate the CCK-1 receptor expression and the function of the CCK-CCK-1 receptor pathway in the human pancreatic adenocarcinoma cell line, Mia PaCa-2.
Methods: The expression of the CCK-1 receptor in Mia PaCa-2 cells was detected by reverse-transcriptase polymerase chain reaction and flow cytometry. CCK-1 receptor agonist CCK-8S (the major transmitter form of CCK) and antagonist lorglumide were cultured respectively with Mia PaCa-2. Three groups were created for this study: CCK-8S group (Mia PaCa-2 cells treated with CCK-8S), lorglumide group (Mia PaCa-2 cells treated with lorglumide), and the control group (Mia PaCa-2 cells alone). Investigators were blinded to group designation. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry were used to detect the cell growth, cell cycle, and apoptosis. Apoptosis index rate was measured by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. Cell invasion ability was observed by invasion assay. Expression of matrix metalloproteinase-2 (MMP-2) was measured by Western blotting.
Results: Mia PaCa-2 cells were found to express the CCK-1 receptor. Compared with the control group (70.2% [1.5%]), CCK-8S was associated with significant mean (SD) cell proliferation (85.1% [1.7%]; P = 0.039), and the ratio in the S stage of the cell cycle increased significantly (50.5% [1.7%] vs 42.2% [1.4%]; P = 0.021). CCK-8S was also associated with increased Mia PaCa-2 cell invasion ability (123.8 [1.7] vs 102.1 [5.8]; P = 0.005 vs control). Compared with the control group, lorglumide was associated with significantly inhibited cell growth (52.1% [1.8%]; P = 0.002) and cell invasion (77.6% [1.2%]; P = 0.003). Lorglumide also induced G0/G1 cell cycle arrest and apoptosis (27.1% [3–5%] vs 3–7% [0.6%]; P = 0.003 vs control). The change of invasion ability appeared to be mediated by MMP-2 expression, which was upregulated by CCK-8S and downregulated by lorglumide.
Conclusion: The findings of this in vitro study suggest that CCK may exert a trophic action on the Mia PaCa-2 cell line, while lorglumide inhibited the cell growth and invasion.
PMCID: PMC3969616  PMID: 24688146
cholecystokinin; CCK-1 receptor; pancreatic cancer; apoptosis; MMP-2
7.  Randomized controlled studies on the efficacy of antiarthritic agents in inhibiting cartilage degeneration and pain associated with progression of osteoarthritis in the rat 
As an initial step in the development of a local therapeutic to treat osteoarthritis (OA), a number of agents were tested for their ability to block activation of inflammation through nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), subchondral bone changes through receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclastogenesis, and proteolytic degradation through matrix metalloproteinase (MMP)-13 activity. Candidates with low toxicity and predicted efficacy were further examined using either of two widely accepted models of OA joint degeneration in the rat: the monoiodoacetic acid (MIA) model or the medial meniscal tear/medial collateral ligament tear (MMT/MCLT) model.
Potential therapeutics were assessed for their effects on the activation of nuclear factor (NF)-κB, RANKL-mediated osteoclastogenesis, and MMP-13 activity in vitro using previously established assays. Toxicity was measured using HeLa cells, a synovial cell line, or primary human chondrocytes. Drugs predicted to perform well in vivo were tested either systemically or via intraarticular injection in the MIA or the MMT/MCLT model of OA. Pain behavior was measured by mechanical hyperalgesia using the digital Randall-Selitto test (dRS) or by incapacitance with weight bearing (WB). Joint degeneration was evaluated using micro computed tomography and a comprehensive semiquantitative scoring of cartilage, subchondral bone, and synovial histopathology.
Several agents were effective both in vitro and in vivo. With regard to pain behavior, systemically delivered clonidine was superior in treating MIA-induced changes in WB or dRS, while systemic clonidine, curcumin, tacrolimus, and fluocinolone were all somewhat effective in modifying MMT/MCLT-induced changes in WB. Systemic tacrolimus was the most effective in slowing disease progression as measured by histopathology in the MMT/MCLT model.
All of the agents that demonstrated highest benefit in vivo, excepting clonidine, were found to inhibit MMP-13, NF-κB, and bone matrix remodeling in vitro. The MIA and MMT/MCLT models of OA, previously shown to possess inflammatory characteristics and to display associated pain behavior, were affected to different degrees by the same drugs. Although no therapeutic was remarkable across all measures, the several which showed the most promise in either model merit continued study with alternative dosing and therapeutic strategies.
Electronic supplementary material
The online version of this article (doi:10.1186/s13075-016-0921-5) contains supplementary material, which is available to authorized users.
PMCID: PMC4721142  PMID: 26794830
Osteoarthritis; Arthritis; Monoiodoacetic; Meniscal; Therapeutics; Degeneration; Pain; NF-κB; RANKL; Bone remodeling
8.  Mesothelin confers pancreatic cancer cell resistance to TNF-α-induced apoptosis through Akt/PI3K/NF-κB activation and IL-6/Mcl-1 overexpression 
Molecular Cancer  2011;10:106.
Previous studies showed that mesothelin (MSLN) plays important roles in survival of pancreatic cancer (PC) cells under anchorage dependent/independent conditions as well as resistance to chemotherapy. The recent success of intratumorally-injected adeno-encoded, chemo/radiation-inducible-promoter driven hTNF-α, (TNFerade) + gemcitabine in pre-clinical models of PC have renewed interest in use of TNF-α as a therapeutic component. To help find additional factors which might affect the therapy, we examined the resistance of MSLN-overexpressing pancreatic cancer cell lines to TNF-α-induced growth inhibition/apoptosis.
Stable MSLN overexpressing MIA PaCa-2 cells (MIA-MSLN), stable MSLN-silenced AsPC-1 cells (AsPC-shMSLN) and other pancreatic cells (MIA-PaCa2, Panc 28, Capan-1, BxPC3, PL 45, Hs 766T, AsPC-1, Capan-2, Panc 48) were used. NF-κB activation was examined by western blots and luciferase reporter assay. TNF-α induced growth inhibition/apoptosis was measured by MTT, TUNEL assay and caspase activation. IL-6 was measured using luminex based assay.
Compared to low endogenous MSLN-expressing MIA PaCa-2 and Panc 28 cells, high endogenous MSLN-expressing Capan-1, BxPC3, PL 45, Hs 766T, AsPC-1, Capan-2, Panc 48 cells were resistant to TNF-α induced growth inhibition. Stable MSLN overexpressing MIA-PaCa2 cells (MIA-MSLN) were resistant to TNF-α-induced apoptosis while stable MSLN-silenced AsPC1 cells (AsPC-shMSLN) were sensitive. Interestingly, TNF-α-treated MIA-MSLN cells showed increased cell cycle progression and cyclin A induction, both of which were reversed by caspase inhibition. We further found that MIA-MSLN cells showed increased expression of anti-apoptotic Bcl-XL and Mcl-1; deactivated (p-Ser75) BAD, and activated (p-Ser70) Bcl-2. Constitutively activated NF-κB and Akt were evident in MIA-MSLN cells that could be suppressed by MSLN siRNA with a resultant increase in sensitivity of TNF-α induced apoptosis. Blocking NF-κB using IKK inhibitor wedelolactone also increased sensitivity to TNF-α-mediated cytotoxicity with concomitant decrease in Mcl-1. Blocking Akt using PI3K inhibitor also had a likewise effect presumably affecting cell cycle. MIA-MSLN cells produced increased IL-6 and were increased furthermore by TNF-α treatment. SiRNA-silencing of IL-6 increased TNF-α sensitivity of MIA-MSLN cells.
Our study delineates a MSLN-Akt-NF-κB-IL-6-Mcl-1 survival axis that may be operative in PC cells, and might help cancer cells' survival in the highly inflammatory milieu evident in PC. Further, for the success of TNFerade + gemcitabine to be successful, we feel the simultaneous inhibition of components of this axis is also essential.
PMCID: PMC3175472  PMID: 21880146
Pancreatic cancer; Mesothelin; TNF-α; Apoptosis
9.  Development of Robust and Standardized Cantilever Sensors Based on Biotin/Neutravidin Coupling for Antibody Detection 
Sensors (Basel, Switzerland)  2013;13(4):5273-5285.
A cantilever-based protein biosensor has been developed providing a customizable multilayer platform for the detection of antibodies. It consists of a biotin-terminated PEG layer pre-functionalized on the gold-coated cantilever surface, onto which NeutrAvidin is adsorbed through biotin/NeutrAvidin specific binding. NeutrAvidin is used as a bridge layer between the biotin-coated surface and the biotinylated biomolecules, such as biotinylated bovine serum albumin (biotinylated BSA), forming a multilayer sensor for direct antibody capture. The cantilever biosensor has been successfully applied to the detection of mouse anti-BSA (m-IgG) and sheep anti-BSA(s-IgG) antibodies. As expected, the average differential surface stress signals of about 5.7 ± 0.8 × 10−3 N/m are very similar for BSA/m-IgG and BSA/s-IgG binding, i.e., they are independent of the origin of the antibody. A statistic evaluation of 112 response curves confirms that the multilayer protein cantilever biosensor shows high reproducibility. As a control test, a biotinylated maltose binding protein was used for detecting specificity of IgG, the result shows a signal of bBSA layer in response to antibody is 5.8 × 10−3 N/m compared to bMBP. The pre-functionalized biotin/PEG cantilever surface is found to show a long shelf-life of at least 40 days and retains its responsivity of above 70% of the signal when stored in PBS buffer at 4 °C. The protein cantilever biosensor represents a rapid, label-free, sensitive and reliable detection technique for a real-time protein assay.
PMCID: PMC3673136  PMID: 23604028
cantilever; biosensor; protein; multilayer; NeutrAvidin; biotin
10.  Development of a Fluorescent-Microsphere Immunoassay for Detection of Antibodies Specific to Equine Arteritis Virus and Comparison with the Virus Neutralization Test▿  
The development and validation of a microsphere immunoassay (MIA) to detect equine antibodies to the major structural proteins of equine arteritis virus (EAV) are described. The assay development process was based on the cloning and expression of genes for full-length individual major structural proteins (GP5 amino acids 1 to 255 [GP51-255], M1-162, and N1-110), as well as partial sequences of these structural proteins (GP51-116, GP575-112, GP555-98, M88-162, and N1-69) that constituted putative antigenic regions. Purified recombinant viral proteins expressed in Escherichia coli were covalently bound to fluorescent polystyrene microspheres and analyzed with the Luminex xMap 100 instrument. Of the eight recombinant proteins, the highest concordance with the virus neutralization test (VNT) results was obtained with the partial GP555-98 protein. The MIA was validated by testing a total of 2,500 equine serum samples previously characterized by the VNT. With the use of an optimal median fluorescence intensity cutoff value of 992, the sensitivity and specificity of the assay were 92.6% and 92.9%, respectively. The GP555-98 MIA and VNT outcomes correlated significantly (r = 0.84; P < 0.0001). Although the GP555-98 MIA is less sensitive than the standard VNT, it has the potential to provide a rapid, convenient, and more economical test for screening equine sera for the presence of antibodies to EAV, with the VNT then being used as a confirmatory assay.
PMCID: PMC2223870  PMID: 18032597
11.  Altered activity patterns of transcription factors induced by endoplasmic reticulum stress 
BMC Biochemistry  2016;17:8.
The endoplasmic-reticulum (ER) responds to the burden of unfolded proteins in its lumen by activating intracellular signal transduction pathways, also known as the unfolded protein response (UPR). Many signal transduction events and transcription factors have been demonstrated to be associated with ER stress. The process in which ER stress affects or interacts with other pathways is still a progressing topic that is not completely understood. Identifying new transcription factors associated with ER stress pathways provides a platform to comprehensively characterize mechanism and functionality of ER.
We utilized a transcription factor (TF) activation plate array to profile the TF activities which were affected by ER stress induced by pharmacological agents, thapsigargin (TG) and tunicamycin (TM) at 1 h, 4 h, 8 h and 16 h respectively, in MiaPACA2 cells. The altered activity patterns were analyzed and validated using gel shift assays and cell-based luciferase reporter assay.
The study has not only confirmed previous findings, which the TFs including ATF4, ATF6, XBP, NFkB, CHOP and AP1, were activated by ER stress, but also found four newly discovered TFs, NFAT, TCF/LEF were activated, and PXR was repressed in response of ER stress. Different patterns of TF activities in MiaPaCa2 were demonstrated upon TM or TG treatment in the time course experiments. The altered activities of TFs were confirmed using gel shift assays and luciferase reporter vectors.
This study utilized a TF activation array technology to identify four new TFs, HIF, NFAT, TCF/LEF and PXR that were changed in their activity as a result of ER stress induced by TG and TM. The TF activity patterns were demonstrated to be diverse in response to the duration of TG or TM treatment. These new findings will facilitate further unveiling the complex mechanisms of the ER stress process and associated diseases.
PMCID: PMC4806502  PMID: 27009139
ER stress; UPR; TF; Plate array; Activation and Signal pathways
12.  An Internet-Based Intervention (Mamma Mia) for Postpartum Depression: Mapping the Development from Theory to Practice 
JMIR Research Protocols  2015;4(4):e120.
As much as 10-15% of new mothers experience depression postpartum. An Internet-based intervention (Mamma Mia) was developed with the primary aims of preventing depressive symptoms and enhancing subjective well-being among pregnant and postpartum women. A secondary aim of Mamma Mia was to ease the transition of becoming a mother by providing knowledge, techniques, and support during pregnancy and after birth.
The aim of the paper is to provide a systematic and comprehensive description of the intervention rationale and the development of Mamma Mia.
For this purpose, we used the intervention mapping (IM) protocol as descriptive tool, which consists of the following 6 steps: (1) a needs assessment, (2) definition of change objectives, (3) selection of theoretical methods and practical strategies, (4) development of program components, (5) planning adoption and implementation, and (6) planning evaluation.
Mamma Mia is a fully automated Internet intervention available for computers, tablets, and smartphones, intended for individual use by the mother. It starts in gestational week 18-24 and lasts up to when the baby becomes 6 months old. This intervention applies a tunneled design to guide the woman through the program in a step-by-step fashion in accordance with the psychological preparations of becoming a mother. The intervention is delivered by email and interactive websites, combining text, pictures, prerecorded audio files, and user input. It targets risk and protective factors for postpartum depression such as prepartum and postpartum attachment, couple satisfaction, social support, and subjective well-being, as identified in the needs assessment. The plan is to implement Mamma Mia directly to users and as part of ordinary services at well-baby clinics, and to evaluate the effectiveness of Mamma Mia in a randomized controlled trial and assess users’ experiences with the program.
The IM of Mamma Mia has made clear the rationale for the intervention, and linked theories and empirical evidence to the contents and materials of the program. This meets the recent calls for intervention descriptions and may inform future studies, development of interventions, and systematic reviews.
PMCID: PMC4704906  PMID: 26476481
early intervention; Internet; intervention mapping; Mamma Mia; postpartum depression; pregnancy; well-being
13.  Targeting cMET with INC280 impairs tumour growth and improves efficacy of gemcitabine in a pancreatic cancer model 
BMC Cancer  2015;15:71.
Expression and activation of the cMET receptor have been implicated in tumor progression and resistance to chemotherapy in human pancreatic cancer. In this regard we assessed the effects of targeting cMET in pancreatic cancer models in vitro and in vivo.
Human (L3.6pl, BxP3, HPAF-II, MiaPaCa2) and murine (Panc02) pancreatic cancer cell lines, endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) were used for the experiments. Furthermore, the human pancreatic cancer cell line MiaPaCa2 with acquired resistance to gemcitabine was employed (MiaPaCa2(G250)). For targeting the cMET receptor, the oral available, ATP-competitive inhibitor INC280 was used. Effects of cMET inhibition on cancer and stromal cells were determined by growth assays, western blotting, motility assays and ELISA. Moreover, orthotopic xenogeneic and syngeneic mouse (BALB-C nu/nu; C57BL/6) models were used to assess in vivo efficacy of targeting cMET alone and in combination with gemcitabine.
Treatment with INC280 impairs activation of signaling intermediates in pancreatic cancer cells and ECs, particularly when cells were stimulated with hepatocyte growth factor (HGF). Moreover, motility of cancer cells and ECs in response to HGF was reduced upon treatment with INC280. Only minor effects on VSMCs were detected. Interestingly, MiaPaCa2(G250) showed an increase in cMET expression and cMET inhibition abrogated HGF-induced effects on growth, motility and signaling as well as DFX-hypoxia HIF-1alpha and MDR-1 expression in vitro. In vivo, therapy with INC280 alone led to inhibition of orthotopic tumor growth in xenogeneic and syngeneic models. Similar to in vitro results, cMET expression was increased upon treatment with gemcitabine, and combination of the cMET inhibitor with gemcitabine improved anti-neoplastic capacity in an orthotopic syngeneic model. Immunohistochemical analysis revealed a significant inhibition of tumor cell proliferation (Ki67) and tumor vascularization (CD31). Finally, combination of gemcitabine with INC280 significantly prolonged survival in the orthotopic syngeneic tumor model even when treatment with the cMET inhibitor was initiated at an advanced stage of disease.
These data provide evidence that targeting cMET in combination with gemcitabine may be effective in human pancreatic cancer and warrants further clinical evaluation.
Electronic supplementary material
The online version of this article (doi:10.1186/s12885-015-1064-9) contains supplementary material, which is available to authorized users.
PMCID: PMC4340491  PMID: 25884642
Pancreatic cancer; cMET; Resistance; Survival
14.  Serological diagnosis of Leptospirosis in bovine serum samples using a microsphere immunoassay 
Veterinary Record Open  2016;3(1):e000148.
Leptospirosis causes significant economic loss within the cattle industry worldwide. Current diagnostic methods are generally inadequate for dealing with large numbers of samples, are outdated, and provide little useful diagnostic and epidemiological information. This aim of this study was to apply a microsphere immunoassay (MIA), utilising Luminex xMap technology, to 200 bovine serum samples to determine this method's usefulness in leptospirosis diagnosis in comparison with the current gold standard, the microscopic agglutination test (MAT). Although MAT is the most widely used laboratory test for the diagnosis of leptospirosis, its reliance on live cultures, subjective interpretation of results and an inability to differentiate between antibody classes, suggest MAT is no longer the best method for the diagnosis of leptospirosis. The results presented in this paper show that MIA was able to determine reactive from non-reactive samples when compared with MAT, and was able to differentiate IgG and IgM classes of antibody. The results suggest increased sensitivity in MIA and the ability to multiplex up to 500 antigens at one time allows for significant improvements in cost-effectiveness as well as a reduced dependency on live cultures. The relatively low cost, high throughput platform and differentiation of antibody class, as shown in previous research, make this assay worthy of consideration for the diagnosis of leptospirosis in small-scale or large-scale bovine populations.
PMCID: PMC4716558  PMID: 26835139
Leptospira; Leptospira hardjo; Cattle; Dairy cattle; Diagnostics
15.  Validation of a Microsphere-Based Immunoassay for Detection of Anti-West Nile Virus and Anti-St. Louis Encephalitis Virus Immunoglobulin M Antibodies▿  
A microsphere-based immunoassay (MIA) was previously developed that is capable of determining the presence of anti-West Nile (WN) virus or anti-St. Louis encephalitis (SLE) virus immunoglobulin M (IgM) antibodies in human serum or cerebrospinal fluid. The original data set on which the classification rules were based comprised 491 serum specimens obtained from the serum bank at the Division of Vector-Borne Infectious Diseases of the Centers for Disease Control and Prevention (DVBID). The classification rules were used to provide a result and to determine whether confirmatory testing was necessary for a given sample. A validation study was coordinated between the DVBID and five state health laboratories to determine (i) the reproducibility of the test between different laboratories, (ii) the correlation between the IgM-enzyme-linked immunosorbent assay (MAC-ELISA) and the MIA, and (iii) whether the initial nonspecific parameters could be refined to reduce the volume of confirmatory testing. Laboratorians were trained in the method, and reagents and data analysis software developed at the DVBID were shipped to each validating laboratory. Validating laboratories performed tests on approximately 200 samples obtained from their individual states, the collections of which comprised approximately equal numbers of WN virus-positive and -negative samples, as determined by MAC-ELISA. In addition, 377 samples submitted to the DVBID for arbovirus testing were analyzed using the MIA and MAC-ELISA at the DVBID only. For the specimens tested at both the state and the DVBID laboratories, a correlation of results indicated that the technology is readily transferable between laboratories. The detection of IgM antibodies to WN virus was more consistent than detection of IgM antibodies to SLE virus. Some changes were made to the analysis software that resulted in an improved accuracy of diagnosis.
PMCID: PMC2043310  PMID: 17609393
16.  Targeting microspheres and cells to polyethylene glycol-modified biological surfaces 
It has previously been demonstrated that damaged arterial tissue can be acutely modified with protein-reactive polyethylene glycol (PEG) to block undesirable platelet deposition. This concept might be expanded by employing PEG-biotin and its strong interaction with avidin for site-specific targeted delivery. Toward this end, cultured endothelial cells (ECs) were surface modified with PEG-biotin and the available biotin was quantified with flow cytometry. NeutrAvidin-coated microspheres and PEG-biotin modified ECs with NeutrAvidin as a bridging molecule were delivered under arterial shear stress to PEG-biotin modified ECs on a coverslip as well as scrape-damaged bovine carotid arteries. After incubation with a 10 mM solution for 1 min, 8 × 107 PEG-biotin molecules/EC were found and persisted for up to 120 h. Perfused microspheres adhered to NHS-PEG-biotin treated bovine carotid arteries with 60 ± 16 microspheres/mm2 versus 11 ± 4 microspheres/mm2 for control arteries (p < 0.015). Similarly, 22 ± 5 targeted ECs/mm2 adhered to NHS-PEG-biotin treated bovine carotid arteries versus 6 ± 2 ECs/mm2 for control arteries (p < 0.01). The targeting strategy demonstrated here might ultimately find application for drug delivery, gene therapy, or cell therapy where localization to specific labeled vascular regions is desired following catheter-based or surgical procedures.
PMCID: PMC2873022  PMID: 17177289
polyethylene glycol; targeted delivery; surface modification; biotin; avidin
17.  Insulin-like growth factor-I receptor in proliferation and motility of pancreatic cancer 
AIM: To develop a molecular therapy for pancreatic cancer, the insulin-like growth factor-I (IGF-I) signaling pathway was analyzed.
METHODS: Pancreatic cancer cell lines (MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4) were cultured in media with 10 mL/L fetal bovine serum. Western blotting analysis was performed to clarify the expression of IGF-I receptor (IGF-IR). Picropodophyllin (PPP), a specific inhibitor of IGF-IR, LY294002, a specific inhibitor of phosphatidylinositol 3 kinase (PI3K), and PD98059, a specific inhibitor of mitogen-activated protein kinase, were added to the media. After 72 h, a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay was performed to analyze cell proliferation. A wound assay was performed to analyze cell motility with hematoxylin and eosin (HE) staining 48 h after addition of each inhibitor.
RESULTS: All cell lines clearly expressed not only IGF-IR but also phosphorylated IGF-IR. PPP significantly suppressed proliferation of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 36.9% ± 2.4% (mean ± SD), 30.9% ± 5.5%, 23.8% ± 3.9%, 37.1% ± 5.3%, 10.4% ± 4.5%, 52.5% ± 4.5% and 22.6% ± 0.4%, at 2 μmol/L, respectively (P < 0.05). LY294002 significantly suppressed proliferation of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 44.4% ± 7.6%, 32.9% ± 8.2%, 53.9% ± 8.0%, 52.8% ± 4.0%, 32.3% ± 4.2%, 51.8% ± 4.5%, and 30.6% ± 9.4%, at 50 μmol/L, respectively (P < 0.05). PD98059 did not significantly suppress cell proliferation. PPP at 2 μmol/L suppressed motility of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 3.0% ± 0.2%, 0%, 0%, 2.0% ± 0.1%, 5.0% ± 0.2%, 3.0% ± 0.1%, and 5.0% ± 0.2%, respectively (P < 0.05). LY294002 at 50 μmol/L suppressed motility of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 to 3.0% ± 0.2%, 0%, 3.0% ± 0.2%, 0%, 0%, 0% and 3% ± 0.1%, respectively (P < 0.05). PD980509 at 20 μmol/L did not suppress motility. Cells were observed by microscopy to analyze the morphological changes induced by the inhibitors. Cells in medium treated with 2 μmol/L PPP or 50 μmol/L LY294002 had pyknotic nuclei, whereas those in medium with 20 μmol/L PD98059 did not show apoptosis.
CONCLUSION: IGF-IR and PI3K are good candidates for molecular therapy of pancreatic cancer.
PMCID: PMC2856825  PMID: 20397262
Insulin-like growth factor-I receptor; Phosphatidylinositol 3 kinase; Pancreatic neoplasms
18.  Immunoliposome-PCR: a generic ultrasensitive quantitative antigen detection system 
The accurate quantification of antigens at low concentrations over a wide dynamic range is needed for identifying biomarkers associated with disease and detecting protein interactions in high-throughput microarrays used in proteomics. Here we report the development of an ultrasensitive quantitative assay format called immunoliposome polymerase chain reaction (ILPCR) that fulfills these requirements. This method uses a liposome, with reporter DNA encapsulated inside and biotin-labeled polyethylene glycol (PEG) phospholipid conjugates incorporated into the outer surface of the liposome, as a detection reagent. The antigenic target is immobilized in the well of a microplate by a capture antibody and the liposome detection reagent is then coupled to a biotin-labeled second antibody through a NeutrAvidin bridge. The liposome is ruptured to release the reporter DNA, which serves as a surrogate to quantify the protein target using real-time PCR.
A liposome detection reagent was prepared, which consisted of a population of liposomes ~120 nm in diameter with each liposome possessing ~800 accessible biotin receptors and ~220 encapsulated reporters. This liposome detection reagent was used in an assay to quantify the concentration of carcinoembryonic antigen (CEA) in human serum. This ILPCR assay exhibited a linear dose–response curve from 10-10 M to 10-16 M CEA. Within this range the assay coefficient of variance was <6 % for repeatability and <2 % for reproducibility. The assay detection limit was 13 fg/mL, which is 1,500-times more sensitive than current clinical assays for CEA. An ILPCR assay to quantify HIV-1 p24 core protein in buffer was also developed.
The ILPCR assay has several advantages over other immuno-PCR methods. The reporter DNA and biotin-labeled PEG phospholipids spontaneously incorporate into the liposomes as they form, simplifying preparation of the detection reagent. Encapsulation of the reporter inside the liposomes allows nonspecific DNA in the assay medium to be degraded with DNase I prior to quantification of the encapsulated reporter by PCR, which reduces false-positive results and improves quantitative accuracy. The ability to encapsulate multiple reporters per liposome also helps overcome the effect of polymerase inhibitors present in biological specimens. Finally, the biotin-labeled liposome detection reagent can be coupled through a NeutrAvidin bridge to a multitude of biotin-labeled probes, making ILPCR a highly generic assay system.
PMCID: PMC3466442  PMID: 22726242
19.  The anti-tumor efficacy of 2-deoxyglucose and D-allose are enhanced with p38 inhibition in pancreatic and ovarian cell lines 
The anti-tumor activity of glucose analogs 2-deoxy-glucose (2-DG) and D-allose was investigated alone or in combination with p38 mitogen-activated protein kinase (MAPK) inhibitor SB202190 or platinum analogs as a strategy to pharmacologically target glycolytic tumor phenotypes.
Hypoxia inducible factor-1 alpha (HIF-1α) protein accumulation in pancreatic cell lines treated with SB202190 alone and in combination with glucose analogs was analyzed by Western blot. HIF-1α transcriptional activity was measured in MIA PaCa-2 cells stably transfected with a hypoxia response element luciferase reporter following treatment with glucose analogs alone, and in combination with SB202190. Induction of cleaved poly(ADP-ribose) polymerase (PARP) was measured by Western blot in the MIA PaCa-2 cells. In vitro anti-proliferative activity of 2-DG and D-allose alone, or in combination with oxaliplatin (pancreatic cell lines), cisplatin (ovarian cell lines), or with SB202190 were investigated using the MTT assay.
SB202190 decreased HIF-1α protein accumulation and transcriptional activity. 2-DG demonstrated greater anti-proliferative activity than D-allose. Pre-treatment with SB202190 enhanced activity of both 2-DG and D-allose in MIA PaCa-2, BxPC-3, ASPC-1, and SK-OV-3 cells. The combination of D-allose and platinum agents was additive to moderately synergistic in all but the OVCAR-3 and HEY cells. SB202190 pre-treatment further enhanced activity of D-allose and 2-DG with platinum agents in most cell lines investigated.
SB202190 induced sensitization of tumor cells to 2-DG and D-allose may be partially mediated by inhibition of HIF-1α activity. Combining glucose analogs and p38 MAPK inhibitors with chemotherapy may be an effective approach to target glycolytic tumor phenotypes.
PMCID: PMC4391305  PMID: 25888489
2-deoxy-glucose; D-allose; Hypoxia inducible factor 1α; Pancreatic cancer; Ovarian cancer; p38 mitogen activated protein kinase
20.  Esculetin induces antiproliferative and apoptotic response in pancreatic cancer cells by directly binding to KEAP1 
Molecular Cancer  2016;15:64.
A handful of studies have exploited antitumor potential of esculetin, a dihydroxy coumarine derivative; the targets to which it binds and the possible downstream mechanism for its cytotoxicity in cancer cells remain to be elucidated. Using pancreatic cancer cell lines as a model system, herein the study was initiated to check the efficacy of esculetin in inhibiting growth of these cancer cells, to decipher mechanism of its action and to predict its direct binding target protein.
The cytotoxicity of esculetin was determined in PANC-1, MIA PaCa-2 and AsPC-1 cell lines; followed by an inspection of intracellular levels of ROS and its associated transcription factor, p65-NF-κB. The interaction between transcription factor, Nrf2 and its regulator KEAP1 was studied in the presence and absence of esculetin. The effect of Nrf2 on gene expression of antioxidant response element pathway was monitored by real time PCR. Thereafter, potential binding target of esculetin was predicted through molecular docking and then confirmed in vitro.
Esculetin treatment in all three pancreatic cancer cell lines resulted in significant growth inhibition with G1-phase cell cycle arrest and induction of mitochondrial dependent apoptosis through activation of caspases 3, 8 and 9. A notable decrease was observed in intracellular ROS and protein levels of p65-NF-κB in PANC-1 cells on esculetin treatment. Antioxidant response regulator Nrf2 has been reportedly involved in crosstalk with NF-κB. Interaction between Nrf2 and KEAP1 was found to be lost upon esculetin treatment in PANC-1 and MIA Paca-2 cells. Nuclear accumulation of Nrf2 and an upregulation of expression of Nrf2 regulated gene NQO1, observed on esculetin treatment in PANC-1 further supported the activation of Nrf2. To account for the loss of Nrf2-KEAP1 interaction on esculetin treatment, direct binding potential between esculetin and KEAP1 was depicted in silico using molecular docking studies. Pull down assay using esculetin conjugated sepharose beads confirmed the binding between esculetin and KEAP1.
We propose that esculetin binds to KEAP1 and inhibits its interaction with Nrf2 in pancreatic cancer cells. This thereby promotes nuclear accumulation of Nrf2 in PANC-1 cells that induces antiproliferative and apoptotic response possibly by attenuating NF-κB.
Electronic supplementary material
The online version of this article (doi:10.1186/s12943-016-0550-2) contains supplementary material, which is available to authorized users.
PMCID: PMC5069780  PMID: 27756327
Esculetin; Coumarins; Molecular target; Pancreatic cancer; Nrf2; KEAP1; NF-κB; ARE pathway; Anticancer compound
21.  Maternal Immune Activation Alters Fetal Brain Development through Interleukin-6 
Schizophrenia and autism are thought to result from the interaction between a susceptibility genotype and environmental risk factors. The offspring of women who experience infection while pregnant have an increased risk for these disorders. Maternal immune activation (MIA) in pregnant rodents produces offspring with abnormalities in behavior, histology, and gene expression that are reminiscent of schizophrenia and autism, making MIA a useful model of the disorders. However, the mechanism by which MIA causes long-term behavioral deficits in the offspring is unknown. Here we show that the cytokine interleukin-6 (IL-6) is critical for mediating the behavioral and transcriptional changes in the offspring. A single maternal injection of IL-6 on day 12.5 of mouse pregnancy causes prepulse inhibition (PPI) and latent inhibition (LI) deficits in the adult offspring. Moreover, coadministration of an anti-IL-6 antibody in the poly(I:C) model of MIA prevents the PPI, LI, and exploratory and social deficits caused by poly(I:C) and normalizes the associated changes in gene expression in the brains of adult offspring. Finally, MIA in IL-6 knock-out mice does not result in several of the behavioral changes seen in the offspring of wild-type mice after MIA. The identification of IL-6 as a key intermediary should aid in the molecular dissection of the pathways whereby MIA alters fetal brain development, which can shed new light on the pathophysiological mechanisms that predispose to schizophrenia and autism.
PMCID: PMC2387067  PMID: 17913903
schizophrenia; autism; cytokine; poly(I:C); maternal immune activation; IL-6; influenza
22.  Hypoxia-inducible factor-1 (HIF-1) is involved in the regulation of hypoxia-stimulated expression of monocyte chemoattractant protein-1 (MCP-1/CCL2) and MCP-5 (Ccl12) in astrocytes 
Neuroinflammation has been implicated in various brain pathologies characterized by hypoxia and ischemia. Astroglia play an important role in the initiation and propagation of hypoxia/ischemia-induced inflammation by secreting inflammatory chemokines that attract neutrophils and monocytes into the brain. However, triggers of chemokine up-regulation by hypoxia/ischemia in these cells are poorly understood. Hypoxia-inducible factor-1 (HIF-1) is a dimeric transcriptional factor consisting of HIF-1α and HIF-1β subunits. HIF-1 binds to HIF-1-binding sites in the target genes and activates their transcription. We have recently shown that hypoxia-induced expression of IL-1β in astrocytes is mediated by HIF-1α. In this study, we demonstrate the role of HIF-1α in hypoxia-induced up-regulation of inflammatory chemokines, human monocyte chemoattractant protein-1 (MCP-1/CCL2) and mouse MCP-5 (Ccl12), in human and mouse astrocytes, respectively.
Primary fetal human astrocytes or mouse astrocytes generated from HIF-1α+/+ and HIF-1α+/- mice were subjected to hypoxia (<2% oxygen) or 125 μM CoCl2 for 4 h and 6 h, respectively. The expression of HIF-1α, MCP-1 and MCP-5 was determined by semi-quantitative RT-PCR, western blot or ELISA. The interaction of HIF-1α with a HIF-1-binding DNA sequence was examined by EMSA and supershift assay. HIF-1-binding sequence in the promoter of MCP-1 gene was cloned and transcriptional activation of MCP-1 by HIF-1α was analyzed by reporter gene assay.
Sequence analyses identified HIF-1-binding sites in the promoters of MCP-1 and MCP-5 genes. Both hypoxia and HIF-1α inducer, CoCl2, strongly up-regulated HIF-1α expression in astrocytes. Mouse HIF-1α+/- astrocytes had lower basal levels of HIF-1α and MCP-5 expression. The up-regulation of MCP-5 by hypoxia or CoCl2 in HIF-1α+/+ and HIF-1α+/- astrocytes was correlated with the levels of HIF-1α in cells. Both hypoxia and CoCl2 also up-regulated HIF-1α and MCP-1 expression in human astrocytes. EMSA assay demonstrated that HIF-1 activated by either hypoxia or CoCl2 binds to wild-type HIF-1-binding DNA sequence, but not the mutant sequence. Furthermore, reporter gene assay demonstrated that hypoxia markedly activated MCP-1 transcription but not the mutated MCP-1 promoter in transfected astrocytes.
These findings suggest that both MCP-1 and MCP-5 are HIF-1 target genes and that HIF-1α is involved in transcriptional induction of these two chemokines in astrocytes by hypoxia.
PMCID: PMC1872020  PMID: 17474992
23.  Excess glucose induces hypoxia-inducible factor-1α in pancreatic cancer cells and stimulates glucose metabolism and cell migration 
Cancer Biology & Therapy  2013;14(5):428-435.
Pancreatic cancer patients frequently show hyperglycemia, but it is uncertain whether hyperglycemia stimulates pancreatic cancer cells. We have investigated whether excess glucose induces hypoxia-inducible factor-1α (HIF-1α) and stimulates glucose metabolism and cell migration in pancreatic cancer cells. We studied wild-type (wt) MiaPaCa2 pancreatic cancer cells and a MiaPaCa2 subline (namely si-MiaPaCa2) that had HIF-1α-specific small interfering RNA. Wt-MiaPaCa2 cells are known to be HIF-1α-positive in hypoxia and HIF-1α-negative in normoxia, whereas si-MiaPaCa2 cells are devoid of HIF-1α in both normoxia and hypoxia. We incubated these cells with different amounts of glucose and determined HIF-1α mRNA and protein by real-time polymerase chain reaction and western blotting. We determined glucose consumption, lactate production and intracellular hexokinase-II and ATP to assess glucose metabolisms and determined pyruvate dehydrogenase kinase-1, reactive oxygen species and fumarate to assess mitochondrial activities. Further, we studied cell migration using a Boyden chamber. Excess glucose (16.7−22.2mM) increased HIF-1α in hypoxic wt-MiaPaCa2 cells. HIF-1α expression increased ATP contents and inhibited mitochondrial activities. Extracellular glucose and hypoxia stimulated glucose metabolisms independent of HIF-1α. Excess glucose stimulated the migration of wt- and si-MiaPaCa2 cells in both normoxia and hypoxia. Thus, glucose stimulated cell migration independent of HIF-1α. Nevertheless, hypoxic wt-MiaPaCa2 cells showed greater migrating ability than their si-MiaPaCa2 counterparts. We conclude that (1) excess glucose increases HIF-1α and ATP in hypoxic wt-MiaPaCa2 cells, (2) extracellular glucose and hypoxia regulate glucose metabolisms independent of HIF-1α and (3) glucose stimulates cell migration by mechanisms that are both dependent on HIF-1α and independent of it.
PMCID: PMC3672187  PMID: 23377827
pancreatic cancer; hypoxia-inducible factor-1; glucose; glycolysis; cell migration; hexokinase-II; reactive oxygen species
24.  Fast, Antigen-Saving Multiplex Immunoassay To Determine Levels and Avidity of Mouse Serum Antibodies to Pertussis, Diphtheria, and Tetanus Antigens ▿ † 
To enhance preclinical evaluation of serological immune responses to the individual diphtheria, tetanus, and pertussis (DTP) components of DTP combination vaccines, a fast hexavalent bead-based method was developed. This multiplex immunoassay (MIA) can simultaneously determine levels of specific mouse serum IgG antibodies to P antigens P.69 pertactin (P.69 Prn), filamentous hemagglutinin (FHA), pertussis toxin (Ptx), and combined fimbria type 2 and 3 antigens (Fim2/3) and to diphtheria toxin (Dtx) and tetanus toxin (TT) in a single well. The mouse DTP MIA was shown to be specific and sensitive and to correlate with the six single in-house enzyme-linked immunosorbent assays (ELISAs) for all antigens. Moreover, the MIA was expanded to include avidity measurements of DTP antigens in a multivalent manner. The sensitivities of the mouse DTP avidity MIA per antigen were comparable to those of the six individual in-house avidity ELISAs, and good correlations between IgG concentrations obtained by both methods for all antigens tested were shown. The regular and avidity mouse DTP MIAs were reproducible, with good intra- and interassay coefficients of variability (CV) for all antigens. Finally, the usefulness of the assay was demonstrated in a longitudinal study of the development and avidity maturation of specific IgG antibodies in mice having received different DTP vaccines. We conclude that the hexaplex mouse DTP MIA is a specific, sensitive, and high-throughput alternative for ELISA to investigate the quantity and quality of serological responses to DTP antigens in preclinical vaccine studies.
PMCID: PMC3122557  PMID: 21325488
25.  Effects of intratracheal administration of nuclear factor-kappaB decoy oligodeoxynucleotides on long-term cigarette smoke-induced lung inflammation and pathology in mice 
Respiratory Research  2009;10(1):79.
To determine if nuclear factor-κB (NF-κB) activation may be a key factor in lung inflammation and respiratory dysfunction, we investigated whether NF-κB can be blocked by intratracheal administration of NF-κB decoy oligodeoxynucleotides (ODNs), and whether decoy ODN-mediated NF-κB inhibition can prevent smoke-induced lung inflammation, respiratory dysfunction, and improve pathological alteration in the small airways and lung parenchyma in the long-term smoke-induced mouse model system. We also detected changes in transcriptional factors. In vivo, the transfection efficiency of NF-κB decoy ODNs to alveolar macrophages in BALF was measured by fluorescein isothiocyanate (FITC)-labeled NF-κB decoy ODNs and flow cytometry post intratracheal ODN administration. Pulmonary function was measured by pressure sensors, and pathological changes were assessed using histology and the pathological Mias software. NF-κB and activator protein 1(AP-1) activity was detected by the electrophoretic motility shift assay (EMSA). Mouse cytokine and chemokine pulmonary expression profiles were investigated by enzyme-linked immunosorbent assay (ELISA) in bronchoalveolar lavage fluid (BALF) and lung tissue homogenates, respectively, after repeated exposure to cigarette smoke. After 24 h, the percentage of transfected alveolar macrophages was 30.00 ± 3.30%. Analysis of respiratory function indicated that transfection of NF-κB decoy ODNs significantly impacted peak expiratory flow (PEF), and bronchoalveolar lavage cytology displayed evidence of decreased macrophage infiltration in airways compared to normal saline-treated or scramble NF-κB decoy ODNs smoke exposed mice. NF-κB decoy ODNs inhibited significantly level of macrophage inflammatory protein (MIP) 1α and monocyte chemoattractant protein 1(MCP-1) in lung homogenates compared to normal saline-treated smoke exposed mice. In contrast, these NF-κB decoy ODNs-treated mice showed significant increase in the level of tumor necrosis factor-α(TNF-α) and pro-MMP-9(pro-matrix metalloproteinase-9) in mice BALF. Further measurement revealed administration of NF-κB decoy ODNs did not prevent pathological changes. These findings indicate that NF-κB activation play an important role on the recruitment of macrophages and pulmonary dysfunction in smoke-induced chronic lung inflammation, and with the exception of NF-κB pathway, there might be complex mechanism governing molecular dynamics of pro-inflammatory cytokines expression and structural changes in small airways and pulmonary parenchyma in vivo.
PMCID: PMC2751757  PMID: 19706153

Results 1-25 (2049042)