Blockade of Nuclear Factor-Κb (NF-Κb) Pathway Using Bay 11-7082 Enhances Arsenic Trioxide-Induced Antiproliferative Activity in U87 Glioblastoma Cells.

Background: Glioblastoma (GBM), the most aggressive and common form of glioma, accounts for over 13,000 death per year in the United States which indicates the importance of developing novel strategies for the treatment of this fatal malignancy. Although Arsenic trioxide (ATO) hinders the growth and survival of GBM cells, the requirement of concentrations higher than 4 µM for triggering apoptotic cell death has questioned its safety profile. Since the NF-κB signaling pathway plays a crucial role in tumorigenesis and chemo-resistance, targeting this oncogenic pathway may sensitize GBM cells to lower concentrations of ATO. Methods: Anti-tumor effects of ATO as monotherapy and in combination with Bay 11-7082 were determined using MTT, crystal violet staining, Annexin V/PI staining and scratch assays. Quantitative reverse transcription-PCR (qRT-PCR) analysis was applied to elucidate the molecular mechanisms underlying the anti-tumor activity of this combination therapy. Results: Our results revealed that ATO and Bay 11-7082 synergistically inhibited the proliferation and survival of GBM cells. Also, it was revealed that NF-κB inhibition using Bay 11-7082 enhanced the inhibitory effects of ATO on migration of GBM cells via suppressing the expression of NF-κB target genes such as TWIST, MMP2, ICAM-1, and cathepsin B. Furthermore, combination treatment of GBM cells with ATO and Bay 11-7082 significantly induce apoptotic cell death coupled with downregulation of NF-κB anti-apoptotic target genes including Bcl-2 and IAP family members. Conclusion: Altogether, these findings suggest that combination therapy with ATO and Bay 11-7082 may be a promising strategy for the treatment of GBM.

Inhibition of c-Myc using 10058-F4 induces anti-tumor effects in ovarian cancer cells via regulation of FOXO target genes.

Ovarian cancer, characterized by rapid growth and asymptomatic development in the early stage, is the fifth common cancer in women. The deregulated expression of c-Myc in more than 50% of human tumors including ovarian cancer makes this oncogenic master transcription factor a potential therapeutic target for cancer treatment. In the present study, we evaluated the anti-tumor effects of 10058-F4, a small molecule c-Myc inhibitor, on ovarian cancer cells. We found that 10058-F4 not only inhibited the proliferation and clonal growth of ovarian cancer cells but also enhanced the cytotoxic effects of chemotherapeutic drugs. Our results also revealed that c-Myc inhibition using 10058-F4 increased the intracellular reactive oxygen species production coupled with suppressed expression of hTERT. RT-qPCR analysis indicated that 10058-F4 enhanced the mRNA levels of the forkhead box O (FOXO) family of transcription factors, including FOXO1, 3, and 4. Moreover, 10058-F4 induced G1 cell cycle arrest in 2008C13 ovarian cancer cells, along with increased expression of some key targets of FOXOs involved in the regulation of cell cycle such as p15, p21, p27, and GADD45A. The results of our study also showed that the 10058-F4-induced apoptosis in 2008C13 cell line was associated with the upregulation of FOXO downstream genes, including PUMA, Bim, and FasL. In conclusion, our results, for the first time, suggest that the anti-tumor effects of 10058-F4 in ovarian cancer cells might be mediated through upregulation of FOXO transcription factors and their key target genes involved in G1 cell cycle arrest, apoptosis, and autophagic cell death.

Anti-proliferative activity of disulfiram through regulation of the AKT-FOXO axis: A proteomic study of molecular targets.

Due to its potent anti-tumor activity, well-investigated pharmacokinetic properties and safety profile, disulfiram (DSF) has emerged as a promising candidate for drug repurposing in cancer therapy. Although several molecular mechanisms have been proposed for its anti-cancer effects, the precise underlying mechanisms remain unclear. In the present study, we showed that DSF inhibited proliferation of cancer cells by inducing reactive oxygen species (ROS) production, a G1 cell cycle arrest and autophagy. Moreover, DSF triggered apoptosis via suppression of the anti-apoptotic protein survivin. To elucidate the mechanisms for the anti-proliferative activities of DSF, we applied a 2-DE combined with MALDI-TOF-MS/MS analysis to identify differentially expressed proteins in breast cancer cells upon treatment with DSF. Nine differentially expressed proteins were identified among which, three candidates including calmodulin (CaM), peroxiredoxin 1 (PRDX1) and collagen type I alpha 1 (COL1A1) are involved in the regulation of the AKT signaling pathway. The results of western blot analysis confirmed that DSF inhibited p-AKT, suggesting that DSF induces its anti-tumor effects via AKT blockade. Moreover, we found that DSF increased the mRNA levels of FOXO1, FOXO3 and FOXO4, and upregulated the expression of their target genes involved in G1 cell cycle arrest, apoptosis and autophagy. Finally, DSF potentiated the anti-proliferative effects of well-known chemotherapeutic agents such as arsenic trioxide (ATO), doxorubicin, paclitaxel and cisplatin. Altogether, these findings provide mechanistic insights into the anti-growth activities of DSF.

Toll-like receptor 4 signaling pathway is correlated with pathophysiological characteristics of AML patients and its inhibition using TAK-242 suppresses AML cell proliferation.

PURPOSE: Acute myeloid leukemia (AML) is one of the most severe blood cancers. Many studies have revealed that inflammation has an essential role in the progression of hematopoietic malignancies. Since the toll-like receptor 4 (TLR4) pathway, an important pathway involved in inflammation induction, has previously been associated with solid tumors, we hypothesized that it would be correlated with the pathophysiological characteristics of AML patients and could be considered as an anticancer target. METHOD: We evaluated the mRNA expression of TLR4, MyD88, RelB, and NF-кB using qRT-PCR in bone-marrow samples of 40 AML patients categorized into four groups according to prognosis, cell type, age, and drug response. Next, we explored the expression of these genes in three AML cell lines (NB4, U937, and KG-1) and used TAK-242, a specific inhibitor of TLR4, to investigate whether this inhibition could suppress AML cell proliferation using cell-cycle analysis. The effect of TAK-242 on arsenic trioxide (ATO) cytotoxicity was also assessed. RESULT: The results of qRT-PCR showed that most genes had higher expression in patients with poor prognosis or drug-resistant statues. They were also overexpressed in patients with less-differentiated cells. Moreover, TAK-242 inhibited cell proliferation of all the cell lines and altered their cell cycle distribution. It could also intensify the cytotoxicity of ATO in combination therapy. CONCLUSION: In sum, the TLR4 pathway was related to pathophysiological characteristics of AML and its inhibition using TAK-242 could be considered as a promising treatment strategy in the TLR4 expressing AML cells, individually or in combination with ATO.

Arsenic trioxide and BIBR1532 synergistically inhibit breast cancer cell proliferation through attenuation of NF-κB signaling pathway.

AIMS: Despite the remarkable anti-proliferative effects of Arsenic trioxide (ATO) in breast cancer cells, the requirement of high, toxic concentrations to induce apoptosis may cause serious side effects in patients. In the present study, we aimed to use BIBR1532, an hTERT inhibitor, in combination with ATO to sensitize MCF7 and MDA-231 cells to lower concentrations of ATO. MAIN METHODS: Breast cancer cell lines MCF7 and MDA-231 were cultured and treated with different doses of ATO and BIBR1532 for 48 h and its effects on cell survival and proliferation were analyzed by MTT, crystal violet staining, colony formation assay, cell cycle, AnnexinV/PI and Real-time PCR tests. KEY FINDINGS: ATO and BIBR1532 synergistically inhibited proliferation and colony-forming ability of breast cancer cells. Besides, BIBR1532 augmented ATO-induced cytotoxic effects via triggering G1 cell cycle arrest and induction of apoptosis coupled with the down-regulation of NF-κB target genes that were involved in cell cycle progression (e.g. CCND1 and CDK6) and prevention of apoptosis such as Bcl-2, Bcl-xl, c-IAP2, and Survivin Respectively. Moreover, ATO-BIBR1532 significantly reduced the mRNA expression level of RELA, NFKB1, and several validated target genes of the NF-κB signaling pathway including NFKBIA, VEGFC, c-Myc, and hTERT. SIGNIFICANCE: The combination of ATO and BIBR1532 synergistically induced its anti-proliferative effect in breast cancer cells by targeting the two key cancer-related pathways, hTERT and NF-κB, and disrupting their feed-forward loop at the same time which result in the reduction of NF-κB transcriptional activity and subsequent down-regulation of its target genes.

Cediranib, an inhibitor of vascular endothelial growth factor receptor kinases, inhibits proliferation and invasion of prostate adenocarcinoma cells.

Prostate Cancer is the second cause of cancer-related death in men and development of metastatic castration-resistant prostate cancer (mCRPC) is the major reason for its high mortality rate. Despite various treatments, all patients succumb to resistant disease, suggesting that there is a pressing need for novel and more efficacious treatments. Members of the vascular endothelial growth factor (VEGF) family play key roles in the tumorigenesis of mCRPC, indicating that VEGF-targeted therapies may have potential anti-tumor efficacy in this malignancy. However, due to compensatory activation of other family members, clinical trials with single-targeted VEGF inhibitors were discouraging. Here, we determined the anti-neoplastic activity of Cediranib, a pan-VEGF receptor inhibitor, in the mCRPC cell lines. Anti-growth effects of Cediranib were studied by MTT and BrdU cell proliferation assays and crystal violet staining. Annexin V/PI, radiation therapy and cell motility assays were carried out to examine the effects of Cediranib on apoptosis, radio-sensitivity and cell motility. Quantitative reverse transcription-PCR (qRT-PCR) and Western blot analyses were conducted to determine the molecular mechanisms underlying the anti-tumor activity of Cediranib. Cediranib decreased cell viability and induced apoptosis via inhibition of the anti-apoptotic proteins. Combination with Cediranib synergistically increased Docetaxel sensitivity and potentiated the effects of radiation therapy. Furthermore, Cediranib impaired cell motility via decrease in the expression of the epithelial-to-mesenchymal transition markers. These findings suggest that Cediranib may have anti-tumor activity in mCRPC cells and warrant further investigation on the therapeutic activity of this pan-VEGF receptor inhibitor in mCRPC.

Blockade of TLR4 using TAK-242 (resatorvid) enhances anti-cancer effects of chemotherapeutic agents: a novel synergistic approach for breast and ovarian cancers.

It is believed that pathways of the immune system are responsible for eradicating cancer cells; however, their over-activation and also their ectopic expression in tumor cells and microenvironment are major contributors to tumor growth and chemoresistance. Toll-like receptor 4 (TLR4) pathway is an innate immune-related pathway which is usually overexpressed in tumor cells that leads to excessive pro-inflammatory cytokines and eventually results in tumor survival, drug resistance, and metastasis. In this study, we investigated whether TLR4 expression is affected upon the treatment of breast and ovarian cancer cells with common chemotherapeutics (paclitaxel, cisplatin, doxorubicin, and arsenic trioxide) and if TLR4 inhibition using its specific inhibitor TAK-242 could enhance cancer cells' response to the drugs. Both breast (MCF7) and ovarian (2008C13) cancer cells experienced an elevated expression of TLR4 after treatment with the drugs. The expression of this receptor was also upregulated in cisplatin-resistant 2008C13 cells; however, it was significantly higher upon short-term treatment with cisplatin. More importantly, the combination treatment of the drugs with TAK-242 intensified the chemosensitivity of six different breast and ovarian cancer cells to chemotherapeutic drugs. It was also identified that co-treatment of paclitaxel and TAK-242 not only led to enhanced G2/M arrest and apoptosis but also satisfactorily decreased the expression of TLR4 and different interleukins in these cells. Taken together, the results of the present study emphasize that chemotherapy may lead to chemoresistance through inducing TLR4 expression, and therefore inhibiting this receptor using TAK-242 could be a promising approach to improve the outcome of chemotherapy in foreseeable future.

The association between ST18 gene polymorphism and severe pemphigus disease among Iranian population.

Recently, ST18 polymorphism has played a role in increasing the risk of pemphigus among some populations such as Egyptian and Jewish. In addition, a variant within the ST18 promoter gene was shown to induce ST18 upregulation and cytokine secretion leading to keratinocyte susceptibility to anti-desmoglein antibodies. Thus, the present study aimed to assess the ST18 single nucleotide polymorphisms (SNP) relationship with pemphigus, disease severity and family history among Iranian population. A total of 111 pemphigus patients and 201 healthy controls were genotyped for three ST18 SNPs rs2304365, rs10504140 and rs4074067 by using TETRA-ARMS PCR method. The results indicated that risk allele A in rs2304365 was significantly higher in pemphigus patients, compared with the amount in the control group (OR = 2.43 CI = 1.49-3.975, P < 0.001). Thus, A allele represents a risk factor for pemphigus. Further, the patients carrying the risk allele had a more severe disease and a higher age of disease onset while no relationship was observed between the number of relapses and positive family history of pemphigus with the risk allele. Finally, dominant model was regarded as the strongest inheritance model for the associated risk. The present study confirmed the relationship between ST18 gene with pemphigus disease, a more severe disease, and a higher age of disease onset.