In previous studies we observed that 2-deoxyglucose blocked the acidification of the medium used for culture of colon cancer cells caused by incubation with biguanides and had an additive inhibitory effect on growth. In the present work, we found that 3-bromopyruvate can also prevent the lowering of pH caused by biguanide treatment. 3-Bromopyruvate inhibited colonic cancer cell proliferation but the effect was not always additive to that of biguanides and an additive effect was more notable in combined treatment with 3-bromopyruvate and 2-deoxyglucose. The induction of alkaline phosphatase activity by butyrate was not consistently affected by combination with other agents that modified glucose metabolism. The drug combinations that were examined inhibited proliferation of wild-type and P53 null cells and affected colonic cancer lines with different growth rates.
Colon cancer; 3-bromopyruvate; metformin; phenformin; 2-deoxyglucose
Oligonucleotides (ONs) have shown great promise as therapeutic agents for various diseases. It is necessary to provide a protocol for preparation of ON-loaded lipid nanoparticles (LNPs) in a reproducible manner on a laboratory scale.
Materials and Methods
A 3-inlet microfluidic (MF) chip-based device was used to synthesize LNPs at the lipid/ON ratio of 10/1 (w/w) and at flow rates ranging from 50 to 1100 µl/min. A series of LNPs containing either antisense oligodeoxyribonucleotide (AS-ODN) or small-interfering RNA (siRNA) were synthesized. Bulk mixing was used as control.
The MF method was shown to be particularly useful for synthesis of LNPs loaded with AS-ODN. The optimal range of flow rates for AS-ODN LNPs was found to be 100 to 200 µl/min. MF synthesis produced LNPs with lower polydispersity values. However, the MF was less effective in preparing LNPs loaded with siRNA, which may have been due to greater rigidity of double-stranded siRNA comparing to single-stranded AS-ODN.
MF technology is a simple, affordable and reproducible method for production of ON-LNPs.
Microfluidics; oligonucleotide; lipid nanoparticles
Disulfide-linked oligodeoxyribonucleotide (ODN) liposomes were formulated and evaluated for the delivery of antisense ODN G3139 in KB human oral carcinoma cells.
Materials and Methods
Liposomes composed of 1,2-di-(9Z-octadecenoyl)-3-trimethylammo-nium-propane (DOTAP)/egg phosphatidylcholine/α-tocopheryl polyethylene glycol 1000 succinate were incorporated with hydrophobized disulfide-linked ODN. Disulfide-linked ODN liposomes were characterized for their size, ODN intracellular delivery, Bcl-2 mRNA and protein expression, growth inhibition, and chemosensitization.
Intracellular delivery of ODN with disulfide-linked ODN liposomes was more efficient than that with non-liposomal hydrophobized disulfide-linked ODN. Treatment of the cells with disulfide-linked ODN liposomes resulted in efficient Bcl-2 down-regulation greater than that with hydrophobized disulfide-linked ODN and consistent with that of cellular growth inhibition and the sensitization to daunorubicin in KB cells. Disulfide-linked ODN liposomes exhibited superior colloidal stability during 5-week storage.
Disulfide-linked liposomes are effective delivery vehicles for antisense ODN.
Liposomes; disulfide; antisense oligonucleotide; G3139; Bcl-2; drug delivery
Liposomes have been successfully used as delivery vehicles for anticancer drugs. Both sonication and microfluidic technologies have been used to produce liposomes. The combination of the two methods was evaluated in this study.
Materials and Methods
The microfluidic devices, mainly comprising micro-dispensers and a sonicator, were used to produce liposomal nanoparticles. Sonication was used to enhance the reduction of liposome size.
Sonication significantly reduced the size of the liposomes. The particle size also decreased as the buffer to solvent flow rate ratio increased. The smallest particle sizes were achieved with a volumetric flow rate of lipids at 0.374 ml/min.
The microfluidic devices in combination with ultrasound are simple and may be used to produce liposomal nanoparticles with narrow size distribution.
Liposomes; microfluidics; ethanol injection; sonication
Worldwide among men, prostate cancer ranks third in cancer occurrence and sixth in cancer mortality. A number of 1, 4-naphthoquinone derivatives have been identified that possess significant pharmacological effects associated with antitumor activities. In this study, the in vitro effects of N-(3-chloro-1,4-dioxo 1,4-dihydronaphthalen-2-yl)-benzamide (NCDDNB) were evaluated on androgen-dependent (CWR-22) and androgen-independent (PC-3, DU-145) human prostate cancer cell lines, and on a normal bone marrow cell line (HS-5). Specifically, the in vitro activity of this compound on cell cycle regulation and apoptosis was evaluated.
Materials and Methods
Established methods of cell viability, cell cycle, Western blot and apoptosis were used.
The effect of NCDDNB on CWR-22, PC-3, DU-145 and HS-5 cells revealed significant anti-tumor activities with IC50s, of 2.5, 2.5, 6.5, and 25 μM respectively. The results of cell cycle analysis showed that NCDDNB arrested PC-3, DU-145, and CWR-22 cells in the G1-phase of the cell cycle. The compound showed no effect on the cell cycle progression in the HS-5 bone marrow cell line. These findings were further validated using Western blot analysis. NCDDNB showed the greatest amount of apoptosis in the androgen-independent PC-3 cells in a time-dependent manner with the apoptotic apex at day 5 of treatment. Furthermore, NCDDNB induced-apoptosis in DU-145 and CWR-22 cells peaked at day 3 of treatment.
Although the mechanism of action of this compound has not been completely elucidated, the effect on the cell cycle and the induction of apoptosis in different prostate cancer cell lines prompted us to carry out a more in-depth preclinical evaluation. This study suggests that NCDDNB may have an impact on treatment of prostate cancer while protecting the bone marrow.
1,4-Naphthoquinone; human prostate cancer cell lines; cytotoxicity; cell cycle; apoptosis
The mechanisms that could explain the poor sensitivity to 5-FU in certain colorectal cancer (CRC) cells were investigated and whether or not co-treatment with low doses of selenium would offer a therapeutic benefit, was explored.
Materials and Methods
Four CRC cell lines (Caco2, RKO, DLD1 and HT-29), with defined tumor signatures and seven different chemical forms of selenium were tested.
5-FU partially inhibited the HT-29 and RKO cells, but had a weak effect on the DLD1 and almost none on the Caco2 cells. Selenous acid and sodium selenite induced growth inhibition of the DLD1, RKO and HT-29 cells, with a marginal effect on the Caco2 cells. The Caco2 cells with mutant p53, failure to activate caspase-8, −9, −7 and −3 and with hypermethylated caspase-8 were resistant to 5-FU. Conversely, RKO cells expressing wild type p53, proteolytically activated caspase-8, −9, −7 and −3 and unmethylated caspase-8 were more responsive to 5-FU and selenous acid induced apoptosis.
Combination treatment with selenous acid may offer an efficacious strategy to overcome 5-FU resistance in certain CRC cells.
Colorectal cancer; caspases; selenium; selenous acid; 5FU; apoptosis
The leading cause of lung cancer is exposure to cigarette smoke and other environmental pollutants, which include formaldehyde, acrolein, benzene, dioxin, and polycyclic aromatic hydrocarbons (PAHs). PAHs and dioxins are exogenous ligands that directly bind to the aryl hydrocarbon receptor (AhR), a transcription factor that activates xenobiotic metabolism, histone modification (an important step in DNA methylation), and, ultimately, tumorigenesis. Here we summarize the current understanding of AhR and its role in the development of lung cancer, including its influence on cell proliferation, angiogenesis, inflammation, and apoptosis.
Aryl hydrocarbon receptor; lung cancer; tumorigenesis; dioxin; polycyclic aromatic hydrocarbons; cigarette smoke
Coumarins belong to an important group of useful drugs with diverse pharmacological properties. In the present study, the in vitro cytotoxicity of new coumarin-based benzopyranone derivatives containing diethylaminoethoxy (5), dimethylaminoethoxy (6), morpholinoethoxy (7), piperidinylethoxy (8) and pyrrolidinylethoxyl (9) amino side chain against human carcinoma (A549) and normal (LL47) lung cell lines was evaluated.
Materials and Methods
The cytotoxicity was evaluated by crystal violet dye binding assay. The effect of compound 9 on different phases of the cell cycle was determined using flow cytometry.
In A549 cells, the 50% lethal dose (LD50) for compounds 5–9 were found to be 7.08, 5.0, 34.2, 8.33 and 5.83 µM, respectively, while in LL47 cells, the LD50 values were found to be 16.7, 20.4, 34.6, 15.4 and 8.75 µM, respectively after 48 h treatment. Cell cycle data indicated that A549 cells were arrested at different phases depending on the concentration.
Compounds 5–9 showed anticancer activity against lung cancer cell lines, while compound 6 showed highly selective anticancer activity.
Coumarin; basic amino side chain; cell viability; cell cycle; benzopyranone derivatives
Ginger root (Zingiber officinale) has been used traditionally for the treatment of gastrointestinal ailments such as motion sickness, dyspepsia and hyperemesis gravidarum, and is also reported to have chemopreventative activity in animal models. The gingerols are a group of structurally related polyphenolic compounds isolated from ginger and known to be the active constituents. Since Helicobacter pylori (HP) is the primary etiological agent associated with dyspepsia, peptic ulcer disease and the development of gastric and colon cancer, the anti-HP effects of ginger and its constituents were tested in vitro.
Materials and Methods
A methanol extract of the dried powdered ginger rhizome, fractions of the extract and the isolated constituents, 6-,8-, 10-gingerol and 6-shogoal, were tested against 19 strains of HP, including 5 CagA+ strains.
The methanol extract of ginger rhizome inhibited the growth of all 19 strains in vitro with a minimum inhibitory concentration range of 6.25–50 µg/ml. One fraction of the crude extract, containing the gingerols, was active and inhibited the growth of all HP strains with an MIC range of 0.78 to 12.5 µg/ml and with significant activity against the CagA+ strains.
These data demonstrate that ginger root extracts containing the gingerols inhibit the growth of H. pylori CagA+ strains in vitro and this activity may contribute to its chemopreventative effects.
Ginger; gingerols; chemoprevention; Helicobacter pylori; Zingiber officinale
To test the activity of novel hydroxyvitamin D3 analogs (20(OH)D3, 20,23(OH)2D and 1,20(OH)2D3) on normal and malignant melanocytes in comparison to 1,25(OH)2D3.
Human epidermal melanocytes and human and hamster melanoma cells were used to measure effects on proliferation and colony formation in monolayer and soft agar. Cell morphology and melanogenesis were also analyzed. QPCR was used to measure gene expression.
Novel secosteroids inhibited proliferation and colony formation by melanoma cells in a similar fashion to 1,25(OH)2D3, having no effect on melanogenesis. These effects were accompanied by ligand-induced translocation of VDR to the nucleus. In normal melanocytes 1α-hydroxyderivatives (1,25(OH)2D3 and 1,20(OH)2D3) had stronger anti-proliferative effects than 20(OH)D3 and 20,23(OH)2D3, and inhibited dendrite formation. The cells tested expressed genes encoding VDR and enzymes that activate or inactivate vitamin D3.
Novel secosteroids show potent anti-melanoma activity in vitro with 20(OH)D3 and 20,23(OH)2D3 being excellent candidates for preclinical testing.
20-hydroxyvitamin D derivatives; melanoma; melanocytes; anti-proliferative activity
The anti-tumor activity of histone deacetylase inhibitors (HDACI) on multi-drug resistant sarcoma cell lines has never been previously described. Four multidrug resistant sarcoma cell lines treated with HDACI PCI-24781 resulted in dose-dependent accumulation of acetylated histones, p21 and PARP cleavage products. Growth of these cell lines was inhibited by PCI-24781 at IC50 of 0.43 to 2.7. When we looked for synergy of PCI-24781 with chemotherapeutic agents, we found that PCI-24781 reverses drug resistance in all four multidrug resistant sarcoma cell lines and synergizes with chemotherapeutic agents to enhance caspase-3/7 activity. Expression of RAD51 (a marker for DNA double-strand break repair) was inhibited and the expression of GADD45α (a marker for growth arrest and DNA-damage) was induced by PCI-24781 in multidrug resistant sarcoma cell lines. In conclusion, HDACI PCI-24781 synergizes with chemotherapeutic drugs to induce apoptosis and reverses drug resistance in multidrug resistant sarcoma cell lines.
histone deacetylase inhibitor; chemotherapy; multidrug resistant; sarcoma
The pyruvic acid analog 3-bromopyruvate (3BrPA) is an alkylating agent known to induce cancer cell death by blocking glycolysis. The anti-glycolytic effect of 3BrPA is considered to be the inactivation of glycolytic enzymes. Yet, there is a lack of experimental documentation on the direct interaction of 3BrPA with any of the suggested targets during its anticancer effect.
Methods and Results
In the current study, using radiolabeled (14C) 3BrPA in multiple cancer cell lines, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was identified as the primary intracellular target of 3BrPA, based on two-dimensional (2D) gel electrophoretic autoradiography, mass spectrometry and immunoprecipitation. Furthermore, in vitro enzyme kinetic studies established that 3BrPA has marked affinity to GAPDH. Finally, Annexin V staining and active caspase-3 immunoblotting demonstrated that apoptosis was induced by 3BrPA.
GAPDH pyruvylation by 3BrPA affects its enzymatic function and is the primary intracellular target in 3BrPA mediated cancer cell death.
3-Bromopyruvate; cancer cell death; GAPDH; glycolysis; Hep3B; HepG2; SK-Hep1
The development of cisplatin drug resistance remains a chief concern in ovarian cancer chemotherapy. β-Elemene is a natural plant product with broad-spectrum antitumor activity towards many types of carcinomas. This study aimed to define the biological and therapeutic significance of β-elemene in chemoresistant ovarian cancer. In the present study, β-elemene significantly inhibited cell growth and proliferation of both the cisplatin-sensitive human ovarian cancer cell line A2780 and its cisplatin-resistant counterpart A2780/CP. β-Elemene also suppressed the growth of several other chemosensitive and chemoresistant ovarian cancer cell lines, including ES-2, MCAS, OVCAR-3, and SKOV-3, with the half maximal inhibitory concentration (IC50) values ranging from 54 to 78 μg/ml. In contrast, the IC50 values of β-elemene for the human ovarian epithelial cell lines IOSE-386 and IOSE-397 were 110 and 114 μg/ml, respectively, which are almost two-fold those for the ovarian cancer cell lines. Cell cycle analysis demonstrated that β-elemene induced a persistent block of cell cycle progression at the G2/M phase in A2780 and A2780/CP cells. This was mediated by alterations in cyclin and cyclin-dependent kinase expression, including the down-regulation of CDC2, cyclin A, and cyclin B1, and the up-regulation of p21WAF1/CIP1 and p53 proteins. Moreover, β-elemene triggered apoptosis and irreversible cell death in both sensitive and resistant ovarian cancer cells via the activation of caspase-3, -8 and 9; the loss of mitochondrial membrane potential (ΔΨm); the release of cytochrome c into the cytosol; and changes in the expression of BCL-2 family proteins. All of these molecular changes were associated with β-elemene-induced growth inhibition and cell death of ovarian cancer cells. Our results demonstrate that β-elemene has antitumor activity against both platinum-sensitive and resistant ovarian cancer cells, and thus has the potential for development as a chemotherapeutic agent for cisplatin-resistant ovarian cancer.
β-Elemene; cisplatin resistance; cell cycle arrest; apoptosis; ovarian cancer; Chinese medicine; A2780; A2780/CP cells; p53; p21WAF/CIP1
Malignant brain tumors are aggressive in both children and adults. Despite recent improvements in diagnostic techniques, therapeutic approaches remain disappointing and unsuccessful. There is an urgent need for promising anticancer agents to improve overall survival of patients with brain cancer. β-Elemene has been shown to have antiproliferative effects on many types of carcinomas. In this study, we compared the cytotoxic efficacy of β-elemene and its synthetic analogs in the brain tumor cell lines A172, CCF-STTG1, and U-87MG. β-Elemene exhibited cytotoxicity towards the tumor lines, effectively suppressing tumor cell survival. The inhibitory effect of β-elemene was mediated by the induction of apoptosis, as demonstrated by three assays. The annexin V assay showed that β-elemene increased the percentage of early- and late-apoptotic cells. Apoptotic nuclei were detected in cancer cells in situ by the terminal deoxynucleotidyltransferase-mediated deoxy-UTP-fluorescein nick end labeling (TUNEL) staining, and the number of TUNEL-positive cells was significantly increased at 24–72 h following drug treatment of the cell lines. Cell death enzyme-linked immunosorbent assay (ELISA) gave similar results. Furthermore, β-elemene increased caspase-3/7/10 activity, up-regulated protein expression of BAX, and down-regulated the one of BCL-2, BCL-XL, and of X-linked inhibitor of apoptosis (XIAP) in the cells, suggesting that apoptotic signaling pathways are involved in the responses triggered by β-elemene. Compared with β-elemene, only three of the 10 synthetic β-elemene analogs studied here, exerted comparable cytotoxic efficacy towards the three brain tumor lines: the analogs Lr-1 and Lr-2 had the same antitumor efficacy, while Lr-3 was less potent than β-elemene. Thus, some synthetic analogs of β-elemene may inhibit brain cancer cell growth and proliferation, and the synthetic analogs Lr-1 and Lr-2 may have great potential as alternatives to β-elemene for anticancer therapy. Overall, this study provides, to our knowledge, the first evidence showing that synthetic analogs of β-elemene hold promise for patients with brain tumors.
Apoptosis; brain cancer; Chinese medicine; β-elemene; A172; U-87MG; CCF-STTG1 cells; synthetic analogs
The role of substance P and the neurokinin-1 receptor (NK-1R) in the transition from inflammation to dysplasia in inflammatory bowel disease is not clear.
Colitis-associated dysplasia was induced in Sprague-Dawley rats by intracolonic, then systemic, administration of trinitrobenzene sulfonic acid. One group of animals received the NK-1R antagonist SR140333; the rest received vehicle. Colons were removed and analyzed for damage and expression of NK-1R downstream components.
The NK-1R antagonist-treated animals had significantly reduced macroscopic and microscopic damage and decreased incidence of inflammatory bowel disease. Twice as many of these animals had a normal diagnosis in any region of the colon. A decrease in proliferation index, Cox-2 expression, and active Erk1/2 was found compared with the vehicle-treated group. In Caco-2 cells, Erk1/2 was activated by substance P and prostaglandin E2.
A selective NK-1R antagonist may delay the development of further colonic damage, offering a potential treatment for patients with long-standing colitis.
Animal model; antagonist; colitis; dysplasia; neurokinin
Chewing of regurgitated food with rumination elicits, gastroesophageal reflux (GER) in baboons. Protracted reflux transforms the distal multilayered squamous cell-lined epithelium into columnar-lined mucosa, with mucus-producing glands having interspersed oxyntic glands. In humans, this histological constellation is called Barrett's mucosa type 2 (BMT2).
Materials and Methods
The distal esophagus together with the proximal stomach was removed en bloc, at autopsy, from 35 adult baboons. Longitudinal sections were stained with toluidine blue, a stain that permits easy discrimination between parietal and chief gastric glands. Using a calibrated ocular scale, the length of the BMT2 was assessed in all 35 baboons.
The mean length of the BMT2 was 9.80 mm (range 1.0 mm–40.2 mm).
BMT2 in baboons is an integrated part of the natural phenomenon of mucosal adaptation to daily regurgitation of gastric acid into the distal esophagus (natural GER), whereas BMT2 in humans might reflect an evolutionary atavism in the esophagus, triggered by a non-physiological disorder (pathological GER). The baboon offers a suitable model to monitor the series of histological events that take place in the distal esophagus under the influence of protracted GER.
Barrett's mucosa; esophagus; baboon; reflux; mucus; metaplasia
The cyclin B1/CDC2 complex governs entry into mitosis by regulating the G2/M checkpoint, and it can be repressed by the tumor suppressor p53. We aimed to determine cyclin B1 expression in squamous cell carcinomas of the head and neck (SCCHN) and correlate it with p53 status and clinicopathological parameters.
Patients and Methods
Cyclin B1 and p53 protein expression was analyzed by immunohistochemistry, and p53 mutation analyses were performed.
Cytoplasmic expression of cyclin B1 was found in all 26 SCCHN studied. In contrast, nuclear staining was seen in the basal layers of normal mucosa. A total of 46% of tumors showed high cyclin B1 expression. p53 was overexpressed in 53.8% of cases, and of these 79% carried a p53 gene mutation. High cyclin B1 expression significantly correlated with the high tumor grade, but not with gender, tumor size, nodal status, local tumor recurrence or p53 expression.
Cyclin B1 is frequently overexpressed in SCCHN, and its high expression is significantly associated with a high tumor grade. These data suggest that cyclin B1 may serve as a potential prognostic biomarker in SCCHN.
Cyclin B1; cell cycle; p53; squamous cell carcinoma; head and neck cancer
Oleanane triterpenoids are broad-spectrum antiproliferative and proapoptotic agents. In this study, we investigated whether reactive oxygen species (ROS) play a role in the antitumor activity of methyl-2-cyano-3, 12-dioxooleana-1, 9(11)-dien-28-oate (CDDO-Me) in OVCAR-5 and MDAH 2774 ovarian cancer cells. Treatment with CDDO-Me caused the generation of ROS (H2O2) and pre-treatment with N-acetylcysteine (NAC) prevented the generation of ROS. NAC also blocked the inhibition of cell proliferation by CDDO-Me. Likewise, NAC prevented the CDDO-Me-caused binding of fluorescein isothiocyanate (FITC)-tagged annexin V, cleavage of poly ADP-ribose polymerase-1 (PARP-1), procaspases-3, -8 and -9 and loss of mitochondrial membrane potential. CDDO-Me inhibited the expression of prosurvival phospho-AKT (p-AKT), phospho-mammalian target of rapamycin (p-mTOR) and nuclear factor-kappa B (NF-κB) (p65) signaling molecules and NF-κB-regulated antiapoptotic B-cell lymphoma-2 (BCL-2), B-cell lymphoma-extra large (BCL-xL), cellular inhibitor of apoptosis protein 1(c-IAP1) and survivin, but pre-treatment with NAC blocked the down-modulation of these signaling and antiapoptotic proteins by CDDO-Me. Together, these results indicate the pivotal role ROS play in the antiproliferative- and apoptosis-inducing activity of CDDO-Me in ovarian cancer cells; however, the role of ROS in the down-regulation of prosurvival AKT, mTOR, NF-κB and antiapoptotic BCL-2, BCL-xL, c-IAP1 and survivin warrants further investigation.
Ovarian cancer; CDDO-Me; apoptosis; ROS; AKT; NF-κB; mTOR
Synthetic oleanane triterpenoids are novel agents which have shown strong antitumorigenic activity against a wide range of cancer types in vitro. The objective of the present study was to determine the anticancer activity of methyl-2-cyano-3, 12-dioxooleana-1, 9(11)-dien-28-oate (CDDO-Me) derived from CDDO, a synthetic analog of oleanolic acid, and its mechanism of action in killing of human ovarian cancer cells. CDDO-Me strongly inhibited the growth of ovarian cancer cells by inducing apoptosis characterized by increased annexin V binding, cleavage of poly (ADP-ribose) polymerase (PARP-1) and procaspases-3, -8 and -9. In addition, CDDO-Me induced mitochondrial depolarization. Western blot analysis showed inhibition of prosurvival (antiapoptotic) phospho-AKT (p-AKT), nuclear factor kappa B (NF-κB) (p65) and phospho- mammalian target of rapamycin (p-mTOR) signaling proteins in cells treated with CDDO-Me. Abrogation of AKT which regulates both NF-κB and mTOR increased the sensitivity of tumor cells to CDDO-Me. Thus, these data showing strong growth-inhibitory and apoptosis-inducing activity of CDDO-Me for ovarian cancer cells through the inhibition of AKT/NF-κB/mTOR signaling pathway provide basis for evaluation of CDDO-Me for ovarian cancer.
Ovarian cancer; methyl-2-cyano-3; 12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me); apoptosis; AKT; NF-κB; mTOR
Therapies that inhibit androgen receptor (AR) are needed for treatment of castration-resistant prostate cancer (CRPC). The ErbB3 binding protein 1 (EBP1) reduces protein expression of both AR and its target genes in CRPC. Although EBP1 regulates AR in hormone-sensitive prostate cancer cells by both destabilizing AR mRNA and inhibiting protein translation, the mechanism of EBP1 down regulation of AR in CRPC is unknown.
Materials and Methods
Western blot and quantitative PCR analysis of cell lysates and polysomes were used to assess AR mRNA, protein expression and translation.
In contrast to hormone- dependent cells, EBP1 did not change steady state levels of AR mRNA or AR mRNA stability in hormone refractory cells. EBP1 did slow protein translation of AR mRNA. The ErbB3/4 ligand heregulin further diminished AR translation in EBP1 - transfected cells, but not in control cells.
These studies suggest that one pathway of EBP1 down-regulation of AR levels may be lost in CRPC.
Prostate cancer; EBP1; mRNA translation; androgen receptor
Saracatinib (AZD0530) is an orally available Src kinase inhibitor. A phase II study was conducted to evaluate saracatinib in patients with recurrent or metastatic head and neck squamous cell cancer (HNSCC).
Patients and Methods
This was an open-label, single-arm, phase II study. Patients received 175 mg saracatinib daily either orally or by percutaneous gastrostomy tube. Radiologic imaging for response was planned at the end of each eight-week cycle.
Nine patients were enrolled. All patients had received prior radiotherapy and six patients had received prior chemotherapy for recurrent or metastatic disease. The most common adverse event was fatigue. Eight patients had progression of disease by response evaluation criteria in solid tumors (RECIST) within the first eight-week cycle and one patient was removed from the study after 11 days due to clinical decline with stable disease according to the RECIST criteria. Median overall survival was six months. The study was closed early due to lack of efficacy according to the early stopping rule.
Single-agent saracatinib does not merit further study in recurrent or metastatic HNSCC.
HNSCC; phase II; Src; AZD0530; saracatinib
(5Z)-7-Oxozeaenol was studied to reveal the path through which it exerts its effects on triple-negative MDA-MB-231 breast cancer cells.
Materials and Methods
The apoptotic effect of (5Z)-7-oxozeaenol on MDA-MB-231 cancer cells was analyzed by cell flow cytometry. The effects of (5Z)-7-oxozeaenol on the expression of the nuclear factor kappa B (NF-κB) p65, p50, IκB kinase (IKKα), IKKβ and caspase-7 were analyzed by western blot. The expression of intracellular reactive oxygen species (ROS) and effects on cell adhesion were also assessed. Cell viability was determined using the 3[4,5-dimethylthiazol-2-yl-]2,5-diphenyl tetrazolium bromide (MTT) assay.
(5Z)-7-Oxozeaenol down-regulated NF-κB in a dose-dependent manner. Intracellular levels of ROS increased in a dose-dependent manner when treated with (5Z)-7-oxozeaenol and potentiated in the presence of H2O2, when compared to paclitaxel which was used as positive control. Treatment with (5Z)-7-oxozeaenol resulted in G1-phase arrest of treated cells and inhibition of cell proliferation. Cell adhesion was notably affected in treated cells. (5Z)-7-Oxozeaenol also significantly enhanced apoptosis of treated cells, through the activation of caspase-7.
Our findings suggest that (5Z)-7-oxozeaenol is a potent up-stream inhibitor of the NF-κB pathway, enhances the sensitivity of treated cells to apoptosis induced by ROS, and affects cell adhesion of MDA-MB-231 breast cancer cells. Thus, (5Z)-7-oxozeaenol is a potential new lead for breast cancer drug development since it might, in combination therapy, enhance the efficacy of current treatments and reduce resistance to chemotherapy of triple negative breast cancer.
(5Z)-7-Oxozeaenol; MDA-MB-231; NF-κB; caspase-7; apoptosis; IKK; ROS
As part of an on going investigation of novel anticancer agents from natural origin, the biological and cellular effects of (5Z)-7-oxozeaenol on cancer cells were investigated.
Materials and Methods
The expression of nuclear factor kappa B (NF-κB), IκB kinase (IKKα), IKKβ and caspase-3 were analyzed by western blot. Reactive oxygen species (ROS) fluorescence and caspase luminescent assays were used to assess the intracellular effects in HeLa cervical and HT-29 colon cancer cell lines. The mitochondrial transmembrane potential (MTP) was analyzed by fluorescence-activated cell sorting (FACS).
Cells treated with (5Z)-7-oxozeaenol exhibited down-regulation of NF-κB in a dose-dependent manner. Treatment with (5Z)-7-oxozeaenol significantly enhanced the levels of ROS in HeLa and HT-29 cells. MTP was reduced in HT-29 cells. The expression of caspase-3 and -7 was induced in (5Z)-7-oxozeaenol treated HeLa cells, in comparison with those treated with paclitaxel.
Our findings suggest that (5Z)-7-oxozeaenol is a potent inhibitor of the NF-κB pathway and potentiates the production of ROS, as well as induces caspase-3 and -7 in HeLa and HT-29 cancer cells. Thus, (5Z)-7-oxozeaenol represents a new lead compound for drug development, particularly as a new cancer chemotherapeutic agent, since programmed cell death might be mediated through the activation of a caspase-arbitrated pathway.
(5Z)-7-Oxozeaenol; NF-κB pathway; apoptosis; caspase; IKKα; IKKβ; ROS; HeLa; HT-29 cells
To assess poly (ADP-ribose) polymerase (PARP) inhibitor MK-4827 together with radiation for the treatment of neuroblastoma.
Material and Methods
Clonogenic survival assays were used to assess MK-4827, radiation and combination thereof in four neuroblastoma cell lines. In vivo efficacy was tested in a murine xenograft model of metastatic neuroblastoma. In vivo targeted inhibition and biological effects included measurement of cleaved caspase-3, gamma-H2AX, and Ki 67 by immunohistochemistry (IHC) and poly-ADP-ribose by Enzyme-Linked Immunosorbent Assay.
Treatment of neuroblastoma cell lines reduced clonogenicity and resulted in additive effects with radiation. In vivo treatment with MK-4827 and radiation prolonged survival (p<0.01) compared to single modalities. In vivo superiority of MK-4827 plus radiation was further documented by significant elevations of cleaved caspase-3 and γ-H2AX in tumors from the combination group compared to single modality cohorts.
Combination of MK-4827 and radiation might provide effective therapy for children with high-risk neuroblastoma.
HER-2 (also called ErbB2 or Neu) tyrosine kinase, one of the four members of ErbB receptor family (ErbBl, i.e., EGFR, ErbB2, ErbB3 and ErbB4), plays a critical role in the control of diverse cellular functions involved in differentiation, proliferation, migration and cell survival via multiple signal transduction pathways. Overexpression of HER-2, observed in HER-2-positive breast cancer patients, is believed to cause the tumor resistance to an array of anti-cancer agents and poor prognosis. Although HER-2 antibodies have shown growth inhibitory effects, more efficient molecular targets against HER-2-mediated tumor resistance need to be developed. The molecular mechanisms underlying HER-2-mediated tumor resistance, especially the connections between HER-2 and therapy-resistant signaling networks, need to be further investigated. NF-κB, a key stress transcription factor that can initiate a pro-survival network, was found to be activated in many cancer cells overexpressing HER-2 and to be responsible for the radiation resistance in HER-2 transfected breast cancer cells. Recent findings in literature and data from this laboratory suggest a possible co-operation between HER-2 and NF-κB in signaling tumor resistance to radiotherapy. This review will discuss the mechanisms of HER-2 mediated NF-κB signaling pathway and potential target for therapeutic intervention.
HER-2; NF-κB; herceptin; drug resistance; radiotherapy resistance; review