Effect of TET1 regulating MGMT on chemotherapy resistance of oral squamous cell carcinoma stem cells.

The study was to evaluate the effect of ten-eleven translocation 1 (TET1) regulating o6-methylguanine-DNA methyltransferase (MGMT) in chemotherapy resistance of oral squamous cell carcinoma (OSCC) stem cells. OSCC stem cells were divided into the blank, negative control (NC), TET1-siRNA, TET1-siRNA + MGMT-OE, and MGMT-OE groups. Methylation-specific polymerase chain reaction (MSP), qRT-PCR and Western blotting were conducted to detect the methylation status of MGMT, expressions of TET1, MGMT, ABCG2, and Oct-4. Cell proliferation, cisplatin chemosensitivity, and cell cycle and apoptosis, were detected using CCK8 and flow cytometry. A chromatin immunoprecipitation (ChIP) assay was employed for detecting the link between TET1 and MGMT gene promoters. In comparison to the NC group, the TET1-siRNA group exhibited increased levels of MGMT methylation, the number of apoptotic cells and cisplatin chemosensitivity consisting of varying concentrations, however, decreased levels of mRNA and protein expressions of TET1 as well as MGMT, cell viability, the number of cells in the S phase, and protein expressions of ABCG2 and Oct-4 were all have diminished amounts. The TET1-siRNA + MGMT-OE and MGMT-OE groups had higher MGMT mRNA and protein expression, as well as increased protein expressions of ABCG2 and Oct-4, greater cell activity, higher number of cells in the S phase, decreased apoptotic rates in cells and decreased cisplatin chemosensitivity with different concentrations. Our study provided evidence that low-expression of TET1 in OSCC stem cells may stimulate MGMT promoter methylation, while inhibiting MGMT mRNA expression, this ultimately strengthens the sensitivity of OSCC stem cells in regards to chemotherapeutics.

Contrastive Analysis of three transplanted tumor models in chick embryo chorioallantoic membrane / 中国比较医学杂志

Objective To compare the growth of three different cancer cell lines on chick chorioallantoic membrane (CAM), to select the best transplanted cancer cell line for establishing a transplanted tumor model and to observe the biological characteristics.Methods The human lung cancer cell line A549, human tongue cancer cell line TCA8113 and human liver cancer cell line QGY7703 were respectively inoculated into CAM at the 7th day of age.The chick embryo survival rate, tumor survival rate, tumor formation rate and induced angiogenesis were detected and the growth characteristics of the transplanted tumor model were observed.Results Compared with the groups inoculated with A549 cells and QGY7703 cells, the tumor formation rate of TCA8113 cells was the highest (P < 0.05), to be the best cancer cell line for transplanted tumor.The optimal inoculated number of cells was 8.0×106/chick embryo, the optimal growth period of the tumor was 4~8 d, and the best experiment time was 7 d after inoculation.Conclusion The TCA-CAM transplanted tumor model of tongue squamous cell cancer is successfully established for further study of the biological characteristics and mechanisms of tumor growth, angiogenesis, invasion and metastasis, and provide a good experimental animal model for anti-tumor drug screening.

The effects of sodium phenylbutyrate(SPB)on the expression of p21 and survivine genes on human tongue squamous cancer cell line Tca8113 / 中国药理学通报

Aim To investigate the effects of sodium phenylbutyrate on cell proliferation,apoptosis and its expression of p21 and survivin genes in human tongue squamous cancer Tca8113 cell line.Methods The cellular proliferation inhibitory ratio was evaluated by MTT assay and the apoptosis and cell cycle of the Tca8113 cell line was detected by FCM.The expression of p21 and survivin genes was analyzed with Western blot and RT-PCR.Results Sodium phenylbutyrate could inhibit the Tca8113 cells proliferation,promote cell apoptosis and arrest the cells at G_1/G_0 phase.The expression of p21 gene in Tca8113 cell line treated by sodium phenylbutyrate was increased,and one of survivin gene was decreased.Conclusions Sodium phenylbutyrate induces up-regulation of p21 gene and down-regulation of survivin gene,which inhibits Tca8113 cell proliferation and induces its apoptosis and arrests the cells at G_1/G_0 phase.And the increase of p21 mRNA expression is negatively correlated with the decrease of survivin mRNA expression(r_s=-0.548,P<0.01),and so is its protein expression(r_s=-0.514,P<0.01).