诱导性一氧化氮抑制剂对鼻咽癌CNE-2细胞株作用的探讨

Exploration of iNOS inhibitor effects to nasopharyngeal cancer cell line CNE-2

目的观察诱导性一氧化氮合酶(iNOS)抑制剂S-甲基异硫脲(SMT)是否对鼻咽癌细胞株CNE-2有抑制细胞增殖的能力和促进凋亡的能力,探讨SMT对顺铂(DDP)的抗CNE-2细胞作用是否存在增敏效应及其分子机制。方法选用鼻咽癌细胞株CNE-2作为研究对象,以A549作为对照,RT-PCR测试CNE-2是否表达iNOS。用不同浓度的SMT、DDP和二者联合干预CNE-2细胞后,MTT试验及集落形成实验观察其对细胞活力的影响。Hoechst33258染色观察细胞凋亡的形态学变化。流式细胞仪检测细胞凋亡的水平。硝酸还原酶法测NO的含量。结果以iNOS高表达的肺癌细胞株A549为阳性对照,CNE-2细胞证实为iNOS阳性表达。SMT能以浓度依赖性的方式有效地抑制CNE-2细胞的增殖。0.5μmol/mL的SMT与6μg/mL的DDP共同干预CNE-2细胞,较之单用SMT或DDP抑制CNE-2细胞的凋亡形态学改变明显,凋亡小体以及核固缩现象增多,早期凋亡率增多(P<0.05)。0.5μmol/mL的SMT与6μg/mL的DDP共同干预CNE-2细胞,与正常组相比,两组NO含量的差异有显著性(P<0.05)。结论 SMT能够有效地和浓度依赖性地抑制CNE-2细胞的增殖。SMT对DDP的抗CNE-2细胞作用具有化疗增敏效应,其机制可能与NO含量有关,但具体增敏机制还有待进一步研究。

[Objective ] To investigate whether the selective iNOS inhibitor SMT can inhibit nasopharyngeal carcinoma cells CNE-2 proliferation, to investigate whether SMT can raise chemotherapy effect of cisplatin on CNE-2 cells and its mechanism. [ Methods ] RT-PCR was used to detect the CNE-2 eell iNOS mRNA expression. The effects of the different treatment （SMT, CDDP, CDDP＋SMT） on CNE-2 cells proliferation were analyzed by MTT assay and colony-forming assay. The morphology of cell apoptosis were analyzed by Hoeehst 33258 staining, and the cell apoptosis index （AI） were analyzed by flow cytometry. The amount of nitric oxide was determined by the nitrate reductase assay. [ Results ] CNE-2 cells expressed iNOS. SMT inhibited CNE-2 cells growth in a dose-dependent manner. 0.5 μmol/mL SMT combined with 6μg/mL eisplatin inhibited CNE-2 cells proliferation and induced CNE-2 cells apoptosis more prominently than they treated CNE-2 cells respectively. Compared with the control group, the ＂ SMT＋eisplatin＂ obviously changed the amount of nitric oxide. [Condusions] SMT inhibited CNE-2 cells growth in a dose dependent manner. SMT can enhance the anti-eaneer effects of cisplafin, the molecular mechanism may relate to the amount of nitric oxide, and the specific mechanisms have yet to be further studied.