HIF-1α siRNA leads to apoptosis of pancreatic cancer cells under hypoxic conditions

OBJECTIVE To explore the role （HIF-1α） in the proliferation and cells under hypoxic conditions. of hypoxic inducible factor-1α apoptosis of pancreatic cancer METHODS A cassette encoding small interference RNA （siRNA） targeting HIF-1α mediated by recombinant adeno-associated virus （rAAV） was constructed, giving rAAV-siHIE rAAV-siHIF or rAAV- hrGFP was transfected into exponentially growing MiaPaCa2 cells under hypoxic conditions. Then, the expression of HIF-1α mRNA and protein, the proliferation and apoptosis of MiaPaCa2 cells were examined, using real-time PCR, Western Blot, MTT and TUNEL, respectively. RESULTS Under hypoxic conditions, rAAV-siHIF inhibited the expression of HIF-1α mRNA and protein in MiaPaCa2 cells. At the same time, rAAV-siHIF decreased MiaPaCa2 cell proliferation and induced apoptosis. However, rAAV-hrGFP had no effect on the expression of HIF-1α as well as the proliferation and apoptosis of MiaPaCa2 cells under hypoxic conditions. CONCLUSION Under hypoxic conditions, HIF-1α plays a key role in the proliferation of MiaPaCa2 cells, and inhibition of HIF- 1α expression can lead to MiaPaCa2 cell apoptosis.     

Tumor dormancy resulting from subcutaneous injection to SCID mice with cultured nasopharyngeal carcinoma cells is mediated via IFN-γ induction of a highly differentiated phenotype

The mechanisms underlying tumor dormancy in human primary lesions and bone marrow metastases of nasopharyngeal carcinoma (NPC) are still not completely understood. The aim of this study was to determine differences in the fates of cultured primary NPC (P-NPC) cells, interferon-γ-transduced primary NPC (IFN-γ-P-NPC) cells, bone marrow metastatic NPC (BM-NPC), and IFN-γ-transduced BM-NPC (IFN-γ-BM-NPC) cells following xenotransplantation into these four groups of SCID mice through subcutaneous injection of 5×10(6) cells/site/animal (4 animals/group). The injected mice were monitored for tumor development at the sites of injection. In only the group injected with IFN-γ-P-NPC cells, the resulting nodules remained small throughout the 60-day observation period after injection, but gradually became palpably prickly. Histopathological examination revealed that these lesions invariably consisted of mostly structures of horny pearls and keratin bridges with occasional apoptotic and degenerative cells. In contrast, animals injected with nontransduced-P-NPC cells developed tumors progressively with occasional central necroses. In the two groups injected with IFN-γ-NPC-BM and NPC-BM cells, progressive growths of tumors were noted, with the latter being at slightly faster rates, whereas the xenografts of both groups showed a poorly differentiated phenotype with abundant vascularity. The study results highlight the high susceptibility of P-NPC but not BM-NPC following IFN-γ gene transfer to the induction of tumor dormancy, which is mediated via induced cell differentiation. Thus, induced cell differentiation could provide a new mechanism by which tumor dormancy is induced.     

NF-κB targeting by way of IKK inhibition sensitizes lung cancer cells to adenovirus delivery of TRAIL

Background  

Lung cancer causes the highest rate of cancer-related deaths both in men and women. As many current treatment modalities are inadequate in increasing patient survival, new therapeutic strategies are required. TNF-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in tumor cells but not in normal cells, prompting its current evaluation in a number of clinical trials. The successful therapeutic employment of TRAIL is restricted by the fact that many tumor cells are resistant to TRAIL. The goal of the present study was to test a novel combinatorial gene therapy modality involving adenoviral delivery of TRAIL (Ad5hTRAIL) and IKK inhibition (AdIKKβKA) to overcome TRAIL resistance in lung cancer cells.     

Correlations of IFN-γ genetic polymorphisms with susceptibility to breast cancer: a meta-analysis

The meta-analysis was conducted to evaluate the correlations between common genetic polymorphisms in the IFN-γ gene and susceptibility to breast cancer. The following electronic databases were searched without language restrictions: MEDLINE (1966?~?2013), the Cochrane Library Database (issue 12, 2013), EMBASE (1980?~?2013), CINAHL (1982?~?2013), Web of Science (1945?~?2013), and the Chinese Biomedical Database (CBM) (1982?~?2013). Meta-analysis was performed with the use of the STATA statistical software. Odds ratios (OR) with their 95 % confidence intervals (95 % CIs) were calculated. Nine clinical case-control studies met all the inclusion criteria and were included in this meta-analysis. A total of 1,182 breast cancer patients and 1,525 healthy controls were involved in this meta-analysis. Three functional polymorphisms were assessed, including rs2069705 C>T, rs2430561 T>A, and CA repeats 2/X. Our meta-analysis results indicated that IFN-γ genetic polymorphisms might be significantly associated with an increased risk of breast cancer (allele model: OR?=?1.37, 95 % CI?=?1.03?~?1.83, P?=?0.031; dominant model: OR?=?1.55, 95 % CI?=?1.01?~?2.37, P?=?0.046; homozygous model: OR?=?2.23, 95 % CI?=?1.30?~?3.82, P?=?0.004; respectively), especially the rs2430561 T>A polymorphism. Subgroup analysis based on ethnicity suggested that genetic polymorphisms in the IFN-γ gene were closely correlated with increased breast cancer risk among Asians (allele model: OR?=?1.21, 95 % CI?=?1.02?~?1.58, P?=?0.017; dominant model: OR?=?3.44, 95 % CI?=?2.07?~?5.71, P?<?0.001; recessive model: OR?=?1.58, 95 % CI?=?1.06?~?2.37, P?=?0.025; homozygous model: OR?=?1.83, 95 % CI?=?1.19?~?2.80, P?=?0.006; respectively), but not among Caucasians (all P?>?0.05). Our meta-analysis supported the hypothesis that IFN-γ genetic polymorphisms may contribute to an increased risk of breast cancer, especially the rs2430561 T>A polymorphism among Asians.     

PPARγ potentiates anticancer effects of gemcitabine on human pancreatic cancer cells

In order to improve the prognosis of patients with unresectable pancreatic cancer, there is an urgent need for enhancement of the anticancer effect of gemcitabine (Gem), a first-line drug for the disease. Here, we demonstrated that ligands for peroxisome proliferator-activated receptor γ (PPARγ) such as pioglitazone (Pio) and rosiglitazone potentiated the cytotoxic action of Gem on human pancreatic cancer cells in a dosage-dependent manner. Notably, the synergistic effect was PPARγ-dependent, since the effect was augmented by PPARγ overexpression and was attenuated by both a PPARγ inhibitor (GW9662) and PPARγ-specific siRNA. To further increase the collaborative effect, the histone deacetylase (HDAC) inhibitor valproic acid (VPA), a known potentiator for PPARγ function, was added to the combinatorial treatment, robustly inducing apoptosis mediated by highly expressed death receptors, including Fas/CD95 and DR5. In xenograft tumor experiments in nude mice, Gem plus Pio significantly suppressed tumor growth as compared with the control treatment, while Gem-only treatment did not. Triple treatment with Gem, Pio, and VPA failed to demonstrate a significant antitumor effect when compared with Gem plus Pio in the current setting. Considered together, Gem plus PPARγ ligands, including Pio, may have therapeutic advantage in the treatment of advanced pancreatic cancer. Since Pio is widely used in the treatment of diabetes mellitus, it may become a feasible partner of Gem-based chemotherapy, fine-tuning the strength of the therapy in a dosage-dependent fashion.     

Decreased accumulation of immune regulatory cells is correlated to the antitumor effect of IFN-γ overexpression in the tumor

During mammary tumorigenesis, there is a profound tumor-induced immunosuppression and a progressive thymic atrophy associated with tumor development. IFN-γ has been shown to be effective in enhancing antitumor responses in several tumor models, however, how IFN-γ exerts its anti-tumor effect is largely controversial. In the present study we have used a mammary tumor model to investigate whether the levels of IFN-γ have an important role in the tumor-induced immuno-suppression as well as in the pathogenesis of the thymic atrophy. We evaluated this possibility using DA-3 cells transfected to express IFN-γ (DA-3/IFN-γ), a system that provides constant, local production of IFN-γ within the tumor microenvironment. Overexpression of IFN-γ in the mammary tumor results in a marked delay of tumor growth, a reduction in regulatory T cells and myeloid-derived suppressor cells accumulation mostly due to down-regulation of chemokines implicated in the recruitment of immune regulatory cells, and a blockage in the tumor-associated thymus atrophy. Collectively, our data suggest that the replacement of the faulty levels of IFN-γ in the tumor results in a diminution of the tumor-induced immune suppression caused by the mammary tumor development.     

Adhesion of renal carcinoma cells to endothelial cells depends on PKCμ

Background  

The formation of metastases includes the separation of tumor cells from the primary tumor, cell migration into subendothelial tissue and cell proliferation in secondary organ. In this process, cell adhesion of tumor cells to the endothelium is an essential requirement for formation of metastases. Protein kinase C (PKC) regulates adhesion and proliferation. To identify a relation between PKC isoforms and tumor progression in renal cell carcinoma (RCC), the influence of PKC isoforms on cell adhesion and proliferation, and possible influences of integrins were analyzed in RCC cells.     

Multivariate analysis of clinicopathologic factors and the efficacy of postoperative IFN-γ adjuvant therapy in 115 patients with renal cell carcinoma

Background. In patients with renal cell carcinoma, the relationship between long term survival and clinicopathologic factors is not clear. We performed a retrospective analysis to determine the usefulness of clinicopathological factors as prognostic predictors in these patients and to evaluate the usefulness of interferon-gamma (IFN-γ) adjuvant therapy in their long term survival. Methods. We performed the analysis in 115 patients with renal cell carcinoma who underwent nephrectomy at our institution, between January 1980 and December 1997. Results. The median follow-up period was 40 months. The overall survival rates at 1, 5, and 10 years were 92.9%, 77.1%, and 77.1%, respectively. Four of the eight prognostic factors evaluated, including growth type, tumor size, clinical stage, local invasion (capsular invasion and microvascular invasion), histopathological architecture, and histopathological grade, were significant by the log-rank test. Multivariate analysis indicated that both growth type (P = 0.0005) and clinical stage (P = 0.0345) were significant independent prognostic factors. Among the 51 patients with clinical stage more advanced than Robson II, or with local invasion, the 5-year survival rate in those with IFN-γ treatment (n = 35) was 68.5 %, while the rate in those without 1FN-γ treatment (n = 16) was 48% (P = 0.0326). Conclusion. This analysis showed that tumor growth type and clinical stage were important prognostic factors. As no effective therapies have yet been established for advanced renal cell carcinoma, further investigation is warranted to determine the value of IFN-γ as a basic therapy for advanced renal cell carcinoma and for these carcinomas of the rapid-growth type. Received: April 10, 1998 / Accepted: January 14, 1999     

Inhibition of RAC1 GTPase sensitizes pancreatic cancer cells to γ-irradiation

Radiation therapy is a staple treatment for pancreatic cancer. However, owing to the intrinsic radioresistance of pancreatic cancer cells, radiation therapy often fails to increase survival of pancreatic cancer patients. Radiation impedes cancer cells by inducing DNA damage, which can activate cell cycle checkpoints. Normal cells possess both a G1 and G2 checkpoint. However, cancer cells are often defective in G1 checkpoint due to mutations/alterations in key regulators of this checkpoint. Accordingly, our results show that normal pancreatic ductal cells respond to ionizing radiation (IR) with activation of both checkpoints whereas pancreatic cancer cells respond to IR with G2/M arrest only. Overexpression/hyperactivation of Rac1 GTPase is detected in the majority of pancreatic cancers. Rac1 plays important roles in survival and Ras-mediated transformation. Here, we show that Rac1 also plays a critical role in the response of pancreatic cancer cells to IR. Inhibition of Rac1 using specific inhibitor and dominant negative Rac1 mutant not only abrogates IR-induced G2 checkpoint activation, but also increases radiosensitivity of pancreatic cancer cells through induction of apoptosis. These results implicate Rac1 signaling in the survival of pancreatic cancer cells following IR, raising the possibility that this pathway contributes to the intrinsic radioresistance of pancreatic cancer.     

Enhanced antiproliferative and apoptotic response to combined treatment of γ-tocotrienol with erlotinib or gefitinib in mammary tumor cells

Background  

Aberrant ErbB receptor signaling is associated with various types of malignancies. γ-Tocotrienol is a member of the vitamin E family of compounds that displays potent anticancer activity that is associated with suppression in ErbB receptor phosphorylation and mitogenic signaling. Erlotinib and gefitinib are tyrosine kinase inhibitors that block ErbB1 receptor activation, whereas trastuzumab is a monoclonal antibody that has been designed to specifically inhibit ErbB2 receptor activation. However, the clinical effectiveness of these agents have been disappointing because of cooperation between different ErbB family members that can rescue cancer cells from agents directed against a single ErbB receptor subtype. It was hypothesized that targeting multiple ErbB receptor subtypes with combined treatment of γ-tocotrienol and ErbB receptor inhibitors would provide greater anticancer effects than monotherapy targeting only a single ErbB receptor subtype.     

5‐Fluorouracil preferentially sensitizes mutant KRAS non‐small cell lung carcinoma cells to TRAIL‐induced apoptosis

Mutations in the KRAS gene are very common in non–small cell lung cancer (NSCLC), but effective therapies targeting KRAS have yet to be developed. Interest in tumor necrosis factor–related apoptosis‐inducing ligand (TRAIL), a potent inducer of cell death, has increased following the observation that TRAIL can selectively kill a wide variety of human cancer cells without killing normal cells both in vitro and in xenograft models. However, results from clinical trials of TRAIL‐based therapy are disappointingly modest at best and many have demonstrated a lack of therapeutic benefit. Current research has focused on selecting a subpopulation of cancer patients who may benefit from TRAIL‐based therapy and identifying best drugs to work with TRAIL. In the current study, we found that NSCLC cells with a KRAS mutation were highly sensitive to treatment with TRAIL and 5‐fluorouracil (5FU). Compared with other chemotherapeutic agents, 5FU displayed the highest synergy with TRAIL in inducing apoptosis in mutant KRAS NSCLC cells. We also found that, on a mechanistic level, 5FU preferentially repressed survivin expression and induced expression of TRAIL death receptor 5 to sensitize NSCLC cells to TRAIL. The combination of low‐dose 5FU and TRAIL strongly inhibited xenograft tumor growth in mice. Our results suggest that the combination of TRAIL and 5FU may be beneficial for patients with mutant KRAS NSCLC.     

Wild-type genotypes of BRCA1 gene SNPs combined with micro-RNA over-expression in mammary tissue leading to familial breast cancer with an increased risk of distant metastases’ occurrence

The objectives of this study were to identify specific long noncoding RNAs (lncRNAs) in laryngeal squamous cell carcinoma (LSCC) and to clarify the function of cisplatin and paclitaxel on the confirmed laryngeal cancer lncRNAs. Fifty-four pairs of laryngeal tumor and adjacent normal tissue were collected. Candidate lncRNAs were searched in authorized databases. The significant lncRNAs were identified and confirmed through high-output real-time PCR. Chemotherapy assay evaluated the influences of cisplatin and paclitaxel on the significant lncRNAs. Thirty-seven cancer-related candidate lncRNAs were selected. Three up-expressed and two down-expressed significant lncRNAs were identified and confirmed. The expressions of lncRNA CDKN2B-AS1, HOTAIR and MALAT1 were dramatically reduced with the increasing concentration of cisplatin and paclitaxel and also lengthening of the treatment duration. Cisplatin and paclitaxel have target function on significant lncRNAs in LSCC, which presents novel molecular targets to cure LSCC patients and also leads an orientation for developing new drugs.     

Grape seed proanthocyanidins inhibit migration potential of pancreatic cancer cells by promoting mesenchymal-to-epithelial transition and targeting NF-κB

Here we explore the effect of grape seed proanthocyanidins (GSPs) on pancreatic cancer cell migration and the molecular mechanisms underlying these effects. Treatment of human pancreatic cancer cell lines Miapaca-2, PANC-1 and AsPC-1 with GSPs resulted in inhibition of cell migration (19–82%, P < 0.01–0.001), which was associated with decreased phosphorylation of ERK1/2 and inactivation of NF-κB. Treatment of cells with UO126, an inhibitor of MEK, and caffeic acid phenethyl ester, an inhibitor of NF-κB, also inhibited the migration of cells (40–80%, P < 0.01–0.001). Inhibition of cell migration by GSPs was associated with reversal of the epithelial-to-mesenchymal transition. This was associated with upregulation of E-cadherin and desmoglein-2 and down-regulation of fibronectin, N-cadherin and vimentin.     

In vitro radiosensitization of human cervical carcinoma cells by combined use of 13-cis-retinoic acid and interferon-α2a

Background: Significant antitumor activity has been reported with the combined use of 13-cis-retinoic acid (cRA) and interferon-α2a (IFN-α) in the treatment of advanced-stage cervical cancers and skin cancers. Since IFN-α has been shown to be a modest radiation enhancer for selected malignant tumor cells and the cytotoxic activity is more enhanced by combining cRA and IFN-α, we hypothesized that the exposure of selected human carcinoma cells to combined cRA and IFN-α would render the cells highly radiosensitive.Methods and Materials: Two human cervical carcinoma cell lines, ME-180 and HeLa-S3, were chosen for the present study because of the different characteristics of the retinoic acid receptor status of the cell lines. To demonstrate the effects of combined cRA and IFN-α treatment on radiation response, we exposed the cells to cRA, IFN-α, or a combination of the drugs for 72 h before radiation. Experiments were carried out at minimally cytotoxic concentrations of the drug for radiation studies. End points of the study were cell growth inhibition and clonogenic ability of the single-plated cells. Effects of cRA and IFN-α on radiation response were quantitatively analyzed by constructing the radiation cell survival curves of ME-180 and HeLa cells.Results: ME-180 cells exhibited varying degrees of cytotoxicity with cRA and IFN-α, while HeLa cells showed no toxic effects with the same treatment. Combined treatment of cRA and IFN-α produced an additive cytotoxic effect in ME-180 cells. Radiosensitization was minimal when ME-180 cells were treated with either cRA or IFN-α before radiation. When ME-180 cells were exposed to 10 μM cRA for 48 h and 1000 U/ml IFN-α for 24 h prior to radiation, there was a significant enhancement in radiation-induced cell killing; the dose modification factor was 2.1 ± 0.9 at the 1% cell-survival level. On the other hand, HeLa-S3 cells exhibited no increased cytotoxicity or radiation enhancement under the same experimental conditions.Conclusion: The present data provide a radiobiological basis for using cRA and IFN-α as a combination radiosensitizer in selected human carcinoma cells.