Search tips
Search criteria

Results 1-14 (14)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
1.  Cyclin-Dependent Kinase 11 (CDK11) is Crucial in the Growth of Liposarcoma Cells 
Cancer letters  2013;342(1):104-112.
Liposarcoma is the second most common soft tissue sarcoma in adults, but treatment options have been quite limited thus far. In this study, we investigated the functional and therapeutic relevance of cyclin-dependent kinase 11 (CDK11) as a putative target in liposarcoma. CDK11 knockdown by synthetic siRNA or lentiviral shRNA decreased cell proliferation, and induced apoptosis in liposarcoma cells. Moreover, CDK11 knockdown enhances the cytotoxic effect of doxorubicin to inhibit cell growth in liposarcoma cells. These findings suggest that CDK11 is critical for the growth and proliferation of liposarcoma cells. CDK11 may be a promising therapeutic target for the treatment of liposarcoma patients.
PMCID: PMC4128631  PMID: 24007862
Kinase; Liposarcoma; CDK11; Tissue microarray; Immunohistochemistry
2.  Phase II study of olaparib in patients with refractory Ewing sarcoma following failure of standard chemotherapy 
BMC Cancer  2014;14(1):813.
Preclinical studies have documented antitumor activity of PARP inhibition both in vitro and in vivo, against Ewing sarcoma cells. This study aimed to translate that observation into a clinical trial to assess the efficacy and tolerability of olaparib, a PARP inhibitor, in patients with advanced Ewing sarcoma (EWS) progressing after prior chemotherapy.
In this nonrandomized phase II trial, adult participants with radiographically measureable metastatic EWS received olaparib tablets, 400 mg orally twice daily, until disease progression or drug intolerance. Tumor measurements were determined by CT or MRI at 6 and 12 weeks after starting olaparib administration, and then every 8 weeks thereafter. Tumor response determinations were made according to RECIST 1.1, and adverse event determinations were made according to CTCAE, version 4.0. A total of 22 participants were planned to be enrolled using a conventional 2-step phase II study design. If no objective responses were observed after 12 participants had been followed for at least 3 months, further accrual would be stopped.
12 participants were enrolled, and all were evaluable. There were no objective responses (PR/CR), 4 SD (duration 10.9, 11.4, 11.9, and 17.9 wks), and 8 PD as best response. Of the SD, 2 had minor responses (−9% and −11.7% by RECIST 1.1). The median time to disease progression was 5.7 weeks. Further enrollment was therefore discontinued. No significant or unexpected toxicities were observed with olaparib, with only a single case each of grade 3 anemia and grade 3 thrombocytopenia observed.
This study is the first report of a prospective phase II trial to evaluate the safety and efficacy of a PARP inhibitor in patients with advanced Ewing sarcoma after failure of standard chemotherapy. Olaparib administration was safe and well tolerated when administered to this small heavily pre-treated cohort at the 400 mg BID dose, although the median duration of dosing was for only 5.7 weeks. No significant responses or durable disease control was seen, and the short average interval to disease progression underscores the aggressiveness of this disease. Other studies to combine cytotoxic chemotherapy with PARP inhibition in EWS are actively ongoing.
Trial registration Identifier: NCT01583543
PMCID: PMC4230717  PMID: 25374341
3.  A-770041 reverses paclitaxel and doxorubicin resistance in osteosarcoma cells 
BMC Cancer  2014;14(1):681.
Reversing multidrug resistance (MDR) has been an important goal for clinical and investigational oncologists. In the last few decades, significant effort has been made to search for inhibitors to reverse MDR by targeting ATP-binding cassette (ABC) transporters (Pgp, MRP) directly, but these efforts have achieved little clinical success. Protein kinases play important roles in many aspects of tumor cell growth and survival. Combinations of kinase inhibitors and chemotherapeutics have been observed to overcome cancer drug resistance in certain circumstances.
We screened a kinase specific inhibitor compound library in human osteosarcoma MDR cell lines to identify inhibitors that were capable of reversing chemoresistance to doxorubicin and paclitaxel.
We identified 18 small molecules that significantly increase chemotherapy drug-induced cell death in human osteosarcoma MDR cell lines U-2OSMR and KHOSR2. We identified A-770041 as one of the most effective MDR reversing agents when combined with doxorubicin or paclitaxel. A-770041 is a potent Src family kinase (Lck and Src) inhibitor. Western blot analysis revealed A-770041 inhibits both Src and Lck activation and expression. Inhibition of Src expression in U-2OSMR and KHOSR2 cell lines using lentiviral shRNA also resulted in increased doxorubicin and paclitaxel drug sensitivity. A-770041 increases the intracellular drug accumulation as demonstrated by calcein AM assay.
These results indicate that small molecule inhibitor A-770041 may function to reverse ABCB1/Pgp-mediated chemotherapy drug resistance. Combination of Src family kinase inhibitor with regular chemotherapy drug could be clinically effective in MDR osteosarcoma.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2407-14-681) contains supplementary material, which is available to authorized users.
PMCID: PMC4177239  PMID: 25236161
Osteosarcoma; MDR; Src kinase; Doxorubicin
Gastrointestinal endoscopy  2011;74(6):1238-1247.
There is limited data on the safety of anesthesia-assisted endoscopy using propofol-mediated sedation in obese individuals undergoing advanced endoscopic procedures (AEPs).
To study the association between obesity [as measured by body mass index (BMI)] and the frequency of sedation-related complications (SRCs) in patients undergoing AEPs.
Prospective cohort study.
Tertiary referral center.
1016 consecutive patients undergoing AEPs [BMI<30: 730(72%), 30-35:159(16%), >35:127(12%)].
Monitored anesthesia sedation with propofol alone or in combination with benzodiazepines and/or opioids.
Main Outcome Measures
SRCs: airway modifications (AMs), hypoxemia, hypotension requiring vasopressors, and early procedure termination were compared across three groups.
There were 203 AMs in 13.9% patients, hypoxemia in 7.3%, need for vasopressors in 0.8% and premature termination in 0.6% of patients. Increasing BMI was associated with an increased frequency of AMs (BMI:<30–10.5%, 30-35–18.9%, >35–26.8%, p<0.001) and hypoxemia (<30–5.3%, 30-35–9.4%, >35–13.4%, p=0.001); there was no difference in the frequency of need for vasopressors (p=0.254) and premature termination of procedures (p=0.401). On multivariable analysis, BMI [OR 2.0 (95% CI 1.3-3.1)], age [OR 1.1 (95% CI 1.0-1.1)] and ASA class ≥ 3 [OR 2.4 (95% CI 1.1-5.0)] were independent predictors of SRCs. In obese individuals (n=286), there was no difference in the frequency of SRCs in patients receiving propofol alone or in combination (p=0.48).
Single tertiary center study.
Although obesity was associated with an increased frequency of SRCs, propofol sedation can be used safely in obese patients undergoing AEPs when administered by trained professionals.
PMCID: PMC4124898  PMID: 22136773
Obesity; propofol; monitored anesthesia care; advanced therapeutic endoscopy
5.  Mechanisms of CFTR Functional Variants That Impair Regulated Bicarbonate Permeation and Increase Risk for Pancreatitis but Not for Cystic Fibrosis 
PLoS Genetics  2014;10(7):e1004376.
CFTR is a dynamically regulated anion channel. Intracellular WNK1-SPAK activation causes CFTR to change permeability and conductance characteristics from a chloride-preferring to bicarbonate-preferring channel through unknown mechanisms. Two severe CFTR mutations (CFTRsev) cause complete loss of CFTR function and result in cystic fibrosis (CF), a severe genetic disorder affecting sweat glands, nasal sinuses, lungs, pancreas, liver, intestines, and male reproductive system. We hypothesize that those CFTR mutations that disrupt the WNK1-SPAK activation mechanisms cause a selective, bicarbonate defect in channel function (CFTRBD) affecting organs that utilize CFTR for bicarbonate secretion (e.g. the pancreas, nasal sinus, vas deferens) but do not cause typical CF. To understand the structural and functional requirements of the CFTR bicarbonate-preferring channel, we (a) screened 984 well-phenotyped pancreatitis cases for candidate CFTRBD mutations from among 81 previously described CFTR variants; (b) conducted electrophysiology studies on clones of variants found in pancreatitis but not CF; (c) computationally constructed a new, complete structural model of CFTR for molecular dynamics simulation of wild-type and mutant variants; and (d) tested the newly defined CFTRBD variants for disease in non-pancreas organs utilizing CFTR for bicarbonate secretion. Nine variants (CFTR R74Q, R75Q, R117H, R170H, L967S, L997F, D1152H, S1235R, and D1270N) not associated with typical CF were associated with pancreatitis (OR 1.5, p = 0.002). Clones expressed in HEK 293T cells had normal chloride but not bicarbonate permeability and conductance with WNK1-SPAK activation. Molecular dynamics simulations suggest physical restriction of the CFTR channel and altered dynamic channel regulation. Comparing pancreatitis patients and controls, CFTRBD increased risk for rhinosinusitis (OR 2.3, p<0.005) and male infertility (OR 395, p<<0.0001). WNK1-SPAK pathway-activated increases in CFTR bicarbonate permeability are altered by CFTRBD variants through multiple mechanisms. CFTRBD variants are associated with clinically significant disorders of the pancreas, sinuses, and male reproductive system.
Author Summary
Genetic disorders of ion channels can affect the body's ability to function properly in many ways. CFTR, an ion channel regulating movement of chloride and bicarbonate across cell membranes, is important for absorbing and secreting fluids. If the gene responsible for the CFTR channel is mutated severely, the result is cystic fibrosis, a hereditary disorder in which the patient develops thick mucus, especially in the lungs, as well as scarring (fibrosis) in the pancreas. Cystic fibrosis also affects the sweat glands, nasal sinuses, intestines, liver, and male reproductive system. Mutations to the CFTR gene that do not cause cystic fibrosis have been considered benign. However, we discovered 9 CFTR mutations that do not cause cystic fibrosis but do cause inflammation and scarring of the pancreas (chronic pancreatitis). These mutant CFTR channels secrete chloride, which is important in the sweat glands, lungs, and intestines, but not bicarbonate, which is important in the pancreas, sinuses, and male reproductive tract. We found patients with any of these 9 mutations had chronic pancreatitis, and often sinus infections, and male infertility, but not other symptoms of cystic fibrosis. Our computer models and data will help researchers develop better drugs and help physicians treating patients with chronic pancreatitis.
PMCID: PMC4102440  PMID: 25033378
6.  Genotyping Cancer-Associated Genes in Chordoma Identifies Mutations in Oncogenes and Areas of Chromosomal Loss Involving CDKN2A, PTEN, and SMARCB1 
PLoS ONE  2014;9(7):e101283.
The molecular mechanisms underlying chordoma pathogenesis are unknown. We therefore sought to identify novel mutations to better understand chordoma biology and to potentially identify therapeutic targets. Given the relatively high costs of whole genome sequencing, we performed a focused genetic analysis using matrix-assisted laser desorption/ionization-time of flight mass spectrometer (Sequenom iPLEX genotyping). We tested 865 hotspot mutations in 111 oncogenes and selected tumor suppressor genes (OncoMap v. 3.0) of 45 human chordoma tumor samples. Of the analyzed samples, seven were identified with at least one mutation. Six of these were from fresh frozen samples, and one was from a paraffin embedded sample. These observations were validated using an independent platform using homogeneous mass extend MALDI-TOF (Sequenom hME Genotyping). These genetic alterations include: ALK (A877S), CTNNB1 (T41A), NRAS (Q61R), PIK3CA (E545K), PTEN (R130), CDKN2A (R58*), and SMARCB1 (R40*). This study reports on the largest comprehensive mutational analysis of chordomas performed to date. To focus on mutations that have the greatest chance of clinical relevance, we tested only oncogenes and tumor suppressor genes that have been previously implicated in the tumorigenesis of more common malignancies. We identified rare genetic changes that may have functional significance to the underlying biology and potential therapeutics for chordomas. Mutations in CDKN2A and PTEN occurred in areas of chromosomal copy loss. When this data is paired with the studies showing 18 of 21 chordoma samples displaying copy loss at the locus for CDKN2A, 17 of 21 chordoma samples displaying copy loss at PTEN, and 3 of 4 chordoma samples displaying deletion at the SMARCB1 locus, we can infer that a loss of heterozygosity at these three loci may play a significant role in chordoma pathogenesis.
PMCID: PMC4077728  PMID: 24983247
7.  Increased fat in pancreas not associated with risk of pancreatitis post-endoscopic retrograde cholangiopancreatography 
A preliminary study has shown increased pancreatic fat in patients with idiopathic pancreatitis and sphincter of Oddi dysfunction. In this study, we aimed to determine if an increased quantity of pancreatic fat is an independent risk factor for pancreatitis post-endoscopic retrograde cholangiopancreatography (ERCP).
In this case control study, we retrospectively reviewed a local radiological and ERCP database to identify patients who had had abdominal magnetic resonance imaging (MRI) followed by ERCP no more than 60 days later between September 2003 and January 2011. Percentage of fat was determined by recording signal intensity in the in-phase (Sin) and out-of-phase (Sout) T1-weighted gradient sequences, and calculation of the fat fraction as (Sin − Sout)/(Sin) × 2 by an abdominal radiologist blinded to clinical history. Controls matched for age, gender, and other pancreatobiliary disease were selected from a group with no post-ERCP pancreatitis (before fat content of the pancreas was analyzed).
Forty-seven patients were enrolled. Compared with controls, subjects with post-ERCP pancreatitis were similar in terms of age (41.4 years versus 41.1 years), gender (21.2% versus 20.2% males), pancreatobiliary disease characteristics, and most ERCP techniques. Measurements of pancreatic head, body, and tail fat and body mass index were similar in patients and controls.
Increased pancreatic fat on MRI criteria is not an independent predictor of post-ERCP pancreatitis.
PMCID: PMC4061141  PMID: 24959090
magnetic resonance imaging; obesity; pancreatic fat; post-ERCP pancreatitis; sphincter of Oddi dysfunction
8.  Synergistic Effects of Targeted PI3K Signaling Inhibition and Chemotherapy in Liposarcoma 
PLoS ONE  2014;9(4):e93996.
While liposarcoma is the second most common soft tissue malignant tumor, the molecular pathogenesis in this malignancy is poorly understood. Our goal was therefore to expand the understanding of molecular mechanisms that drive liposarcoma and identify therapeutically-susceptible genetic alterations. We studied a cohort of high-grade liposarcomas and benign lipomas across multiple disease sites, as well as two liposarcoma cell lines, using multiplexed mutational analysis. Nucleic acids extracted from diagnostic patient tissue were simultaneously interrogated for 150 common mutations across 15 essential cancer genes using a clinically-validated platform for cancer genotyping. Western blot analysis was implemented to detect activation of downstream pathways. Liposarcoma cell lines were used to determine the effects of PI3K targeted drug treatment with or without chemotherapy. We identified mutations in the PIK3CA gene in 4 of 18 human liposarcoma patients (22%). No PIK3CA mutations were identified in benign lipomas. Western blot analysis confirmed downstream activation of AKT in both PIK3CA mutant and non-mutant liposarcoma samples. PI-103, a dual PI3K/mTOR inhibitor, effectively inhibited the activation of the PI3K/AKT in liposarcoma cell lines and induced apoptosis. Importantly, combination with PI-103 treatment strongly synergized the growth-inhibitory effects of the chemotherapy drugs doxorubicin and cisplatin in liposarcoma cells. Taken together, these findings suggest that activation of the PI3K/AKT pathway is an important cancer mechanism in liposarcoma. Targeting the PI3K/AKT/pathway with small molecule inhibitors in combination with chemotherapy could be exploited as a novel strategy in the treatment of liposarcoma.
PMCID: PMC3973642  PMID: 24695632
9.  A Randomized Trial of Rectal Indomethacin to Prevent Post-ERCP Pancreatitis 
The New England Journal of Medicine  2012;366(15):1414-1422.
Preliminary research suggests that rectally administered nonsteroidal antiinflammatory drugs may reduce the incidence of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP).
In this multicenter, randomized, placebo-controlled, double-blind clinical trial, we assigned patients at elevated risk for post-ERCP pancreatitis to receive a single dose of rectal indomethacin or placebo immediately after ERCP. Patients were determined to be at high risk on the basis of validated patient- and procedure-related risk factors. The primary outcome was post-ERCP pancreatitis, which was defined as new upper abdominal pain, an elevation in pancreatic enzymes to at least three times the upper limit of the normal range 24 hours after the procedure, and hospitalization for at least 2 nights.
A total of 602 patients were enrolled and completed follow-up. The majority of patients (82%) had a clinical suspicion of sphincter of Oddi dysfunction. Post-ERCP pancreatitis developed in 27 of 295 patients (9.2%) in the indomethacin group and in 52 of 307 patients (16.9%) in the placebo group (P = 0.005). Moderate-to-severe pancreatitis developed in 13 patients (4.4%) in the indomethacin group and in 27 patients (8.8%) in the placebo group (P = 0.03).
Among patients at high risk for post-ERCP pancreatitis, rectal indomethacin significantly reduced the incidence of the condition. (Funded by the National Institutes of Health; number, NCT00820612.)
PMCID: PMC3339271  PMID: 22494121
10.  Bedside Endoscopic Ultrasound in Critically Ill patients 
Background. The aim of this study was to evaluate the role and impact of EUS in the management of critically ill patients. Methods. We retrospectively identified all patients at our institution over a 68-month period in whom bedside inpatient EUS was performed. EUS was considered to have a significant impact if a new diagnosis was established and/or the findings altered subsequent clinical management. Results. Fifteen patients (9 male; mean age 58 ± 15 years) underwent bedside EUS without complications. EUS-FNA (median 4 passes; range 2–7) performed in 12 (80%) demonstrated a malignant mediastinal mass/lymph node (5), pancreatic abscess (1), excluded a pelvic abscess (1), established enlarged gastric folds as benign (1) and excluded malignancy in enlarged mediastinal (1) and porta hepatis adenopathy (1). In two patients, EUS-FNA failed to diagnose mediastinal histoplasmosis (1) and a hemorrhagic pancreatic pseudocyst (1). In three diagnostic exams without FNA, EUS correctly excluded choledocholithaisis (n = 1) and cholangiocarcinoma (1), and found gastric varices successfully thrombosed after previous cyanoacrylate injection (1). EUS was considered to have an impact in 13/15 (87%) patients. Conclusions. In this series, bedside EUS in critically ill patients was technically feasible, safe and had a major impact on the majority of patients.
PMCID: PMC3123909  PMID: 21747653
11.  Serum Neuregulin-1β as a Biomarker of Cardiovascular Fitness 
Neuregulins (NRG) are growth factors that bind to receptors of the erbB family, and are known to mediate a number of processes involved in diverse tissues. Neuregulin-1β is expressed in skeletal muscle and is activated by exercise. We hypothesized that NRG-1β might circulate in the bloodstream and increase as a consequence of physical activity. A study was conducted in healthy subjects to determine if NRG-1β is immunodetectable in human serum, and if so whether levels relate acutely or chronically to exercise.
Nine healthy men underwent three bouts of exercise of varying degrees of intensity on a bicycle ergometer over a period of three weeks. Cardio-respiratory fitness was determined by measurement of maximal oxygen uptake (VO2max). Serum was sampled prior to and immediately after each session (up to 30 minutes post) and serum NRG-1β was quantified utilizing an indirect sandwich ELISA assay developed in our lab.
Across subjects, mean serum NRG-1β levels ranged from 32 ng/mL to 473 ng/mL. Individual subjects showed relatively stable levels during the study period that did not change acutely after exercise. Serum NRG-1β demonstrated a positive correlation with VO2max (r2=0.49, p =.044).
These preliminary observations suggest that at least in healthy men, serum NRG-1β is an indicator of cardio-respiratory fitness and does not change acutely with exercise.
PMCID: PMC2903891  PMID: 20634924
Growth Factor; Exercise; heregulin; cardiopulmonary fitness
12.  Palmitate alters neuregulin signaling and biology in cardiac myocytes 
The saturated fatty acid palmitate alters normal cell function via disruption of cell signaling, and these effects have been implicated in the end-organ damage associated with dyslipidemia. Neuregulin-1β (NRG-1β) is a growth and survival factor in cardiac myocytes. We tested the hypothesis that palmitate alters NRG-1β signaling and biology in isolated neonatal rat cardiac myocytes. Palmitate treatment inhibited NRG-1β activation of the PI3kinase/Akt pathway in myocytes. We found that the pro-apoptotic activity of palmitate was increased by NRG-1β treatment. The effects of palmitate on NRG-1β signaling and survival were reversed by the mono-unsaturated fatty acid oleate. Under control conditions NRG-1β decreases p53 expression in myocytes. In the presence of palmitate, NRG-1β caused an increase in p53 expression, bax multimer formation, concurrent with degradation of mdm2, a negative regulator of p53. Thus in the presence of palmitate NRG-1β activates pro-apoptotic, rather than pro-survival signaling in cardiac myocytes.
PMCID: PMC2654183  PMID: 19070592
13.  Differentiation of Dextran-Producing Leuconostoc Strains by a Modified Randomly Amplified Polymorphic DNA Protocol 
Seven dextran-producing Leuconostoc strains were differentiated by using a modified randomly amplified polymorphic DNA (RAPD) protocol that incorporated specific primers designed from conserved regions of dextransucrase genes. RAPD profiles showed intraspecies differences among the Leuconostoc mesenteroides strains tested. This modified RAPD protocol will aid in the differentiation of polymer-producing leuconostocs, which are currently distinguished by time-consuming analyses of the dextrans they synthesize.
PMCID: PMC106824  PMID: 9687482
14.  A Pilot Study to Develop a Diagnostic Test for Pancreatic Ductal Adenocarcinoma Based on Differential Expression of Select miRNA in Plasma and Bile 
Accurate peripheral markers for the diagnosis of pancreatic ductal adenocarcinoma (PDAC) are lacking. We measured the differential expression of select microRNAs (miRNAs) in plasma and bile among patients with PDAC, chronic pancreatitis (CP), and controls.
We identified patients (n=215) with treatment-naive PDAC (n=77), CP with bile/pancreatic duct pathology (n=67), and controls (n=71) who had been prospectively enrolled in a Pancreatobiliary Biorepository at the time of endoscopic retrograde cholangiopancreatography or endoscopic ultrasound. Controls were patients with choledocholithiasis but normal pancreata. The sample was separated into training (n=95) and validation (n=120) cohorts to establish and then test the performance of PDAC Signature Panels in diagnosing PDAC. The training cohort (n=95) included age-matched patients with PDAC, CP, and controls. Panels were derived from the differential expression of 10 candidate miRNAs in plasma or bile. We selected miRNAs having excellent accuracy for inclusion in regression models.
Using the training cohort, we confirmed the differential expression of 9/10 miRNAs in plasma (miR-10b, -30c, -106b, -132, -155, -181a, -181b, -196a, and -212) and 7/10 in bile (excluding miR-21, -132, and -181b). Of these, five (miR-10b, -155, -106b, -30c, and -212) had excellent accuracy for distinguishing PDAC. In the training and validation cohorts, the sensitivity/specificity for a PDAC Panel derived from plasma was 95/100% and 100/100%, respectively; in bile, these were 96/100% and 100/100%.
Increased expression of miRNA-10b, -155, and -106b in plasma appears highly accurate in diagnosing PDAC. Additional studies are needed to confirm this Panel and explore its value as a prognostic test.
PMCID: PMC4261139  PMID: 25350767

Results 1-14 (14)