Jiang Z

miR-10b Promotes Migration and Invasion in Nasopharyngeal Carcinoma Cells

MicroRNA-10b (miR-10b) has been reported to play an important role in some types of cancer, but the effects and possible mechanisms of action of miR-10b in the metastasis of nasopharyngeal carcinoma cells (NPC) have not been explored. The aim of the present study was to investigate the function of miR-10b in nasopharyngeal carcinoma and to determine the molecular mechanisms underlying its action. The MTT assay was used to assess proliferation of CNE-2Z cells. Wound healing and transwell migration assays were applied to assess cell migration and invasion, while and expression of E-cadherin and MMP-9 were detected using Western blot analysis. Real-time PCR was employed to detect the expression of genes related to migration and invasion and the 2-??Ct method was used to calculate the degree of expression. MTT assay showed the expression of miR-10b to have no effect on the proliferation of NPC cell lines. The wound healing assay showed that miR-10b mimics promoted the mobility and invasion of NPC cell lines. Inhibitors of miR-10b reduced the ability of NPC cell lines to migrate and invade. In addition, the expression of genes related to migration and invasion, such as E-cadherin, vimentin, and MMP-9, were confirmed to be different in the CNE-2Z NPC cell line transfected with miR-10b mimics and with miR-10b inhibitors. In the present study, miR-10b was found to upregulate the expression of MMP-9 and knockdown of miR-10b was found to significantly downregulate the expression of E-cadherin. On the whole, these results showed that miR-10b plays an important role in the invasion and metastasis of NPC cells.

3-Bromopyruvate induces apoptosis in breast cancer cells by downregulating Mcl-1 through the PI3K/Akt signaling pathway.

The hexokinase inhibitor 3-bromopyruvate (3-BrPA) can inhibit glycolysis in tumor cells to reduce ATP production, resulting in apoptosis. However, as 3-BrPA is an alkylating agent, its cytotoxic action may be induced by other molecular mechanisms. The results presented here reveal that 3-BrPA-induced apoptosis is caspase independent. Further, 3-BrPA induces the generation of reactive oxygen species in MDA-MB-231 cells, leading to mitochondria-mediated apoptosis. These results suggest that caspase-independent apoptosis may be induced by the generation of reactive oxygen species. In this study, we also demonstrated that 3-BrPA induces apoptosis through the downregulation of myeloid cell leukemia-1 (Mcl-1) in MDA-MB-231 breast cancer cells. The results of Mcl-1 knockdown indicate that Mcl-1 plays an important role in 3-BrPA-induced apoptosis. Further, the upregulation of Mcl-1 expression in 3-BrPA-treated MDA-MB-231 cells significantly increases cell viability. In addition, 3-BrPA treatment resulted in the downregulation of p-Akt, suggesting that 3-BrPA may downregulate Mcl-1 through the phosphoinositide-3-kinase/Akt pathway. These findings indicate that 3-BrPA induces apoptosis in breast cancer cells by downregulating Mcl-1 through the phosphoinositide-3-kinase/Akt signaling pathway.

Inhibition of autophagy by 3-MA enhances endoplasmic reticulum stress-induced apoptosis in human nasopharyngeal carcinoma cells

Radiotherapy and adjuvant cisplatin chemotherapy are the mainstream treatments for nasopharyngeal carcinoma (NPC), which effectively improve the outcome and reduce tumor recurrence. However, the resistance mechanism(s) involved in radiotherapy and chemotherapy, which is the main barrier in NPC treatment, remains undefined. Therefore, there is an urgent requirement for the identification of new therapeutic strategies or adjuvant drugs. In the present study, the effects of autophagy inhibitors on endoplasmic reticulum (ER) stress-induced autophagy was investigated. Combining 3-methyladenine (3-MA) with cisplatin (DDP), ionizing radiation (IR), 2-deoxy-D-glucose (2-DG) or tunicamycin (TM) resulted in enhanced cell death, as revealed by MTT and colony formation assays. Flow cytometry results demonstrated that the sensitivity of NPC cells to DDP- and IR-induced apoptosis was not significant. DDP, IR, 2-DG and TM induced ER stress and autophagy. Using fluorescence microscopy, 3-MA was identified to increase the apoptotic cell death induced by DDP, IR, 2-DG or TM. In addition, 3-MA inhibited the increased autophagy induced by DDP, IR, 2-DG or TM, as demonstrated by western blot analysis and immunocytochemistry results. Results of the present study indicate that autophagy acts as a protective mechanism response to the apoptosis induced by DDP, IR, 2-DG or TM.

Cisplatin combined with metformin inhibits migration and invasion of human nasopharyngeal carcinoma cells by regulating E-cadherin and MMP-9.

Metformin has been shown to be useful in reducing insulin resistance by restoring sensitivity. Recent evidence suggests that metformin might also possess anti-tumour activity. This study aimed to investigate the effects of cisplatin combined with metformin on the proliferation, invasion and migration of HNE1/DDP human nasopharyngeal carcinoma (NPC) cells, and to provide a new target for treating metastasis. The MTT assay was used to assess viability of HNE1/DDP cells after exposure to different concentrations of 2, 5-diaminopyrimidine-4, 6-diol (DDP; 2, 4, 8, 16, and 32 μmol·L(-1)), metformin (5, 10, 15, 20, and 25 μmol·L(-1)), and 4 μmol·L(-1) of DDP combined with metformin. Wound healing and transwell migration assays were performed to assess cell migration and invasion, and expression of E-cadherin and MMP-9 was detected using Western blotting. MTT assay results showed that DDP could inhibit the proliferation of HNE1/DDP cells in a time- and concentration-dependent manner, with an IC50 of 32.0 μmol·L(-1) at 24 h (P < 0.05), whereas low concentrations of DDP had almost no inhibitory effects on cell invasion and migration. DDP combined with metformin significantly inhibited cell invasion and migration. In addition, genes related to migration and invasion, such as those of E-cadherin and MMP-9, showed differential expression in the NPC cell line HNE1/DDP. In the present study, with an increasing concentration of metformin, the expression of MMP-9 was downregulated whereas that of E-cadherin was significantly upregulated. Taken together, our results show that cisplatin combined with metformin has effects on proliferation, invasion, and migration of human NPC cells.