Cisplatin-induced Senescence and Senescence-related Gene Expression Profiles in Human Nasopharyngeal Carcinoma Cells CNE2

Objective To investigate the effects of cisplatin induction in vitro on human nasopharyngeal carcinoma cells CNE2 and its possible molecular mechanism. Methods Proliferation of CNE2 cells treated with various concentrations(0.4-4.0 mg/L) of cisplatin was determined using MTT assay. The senescent cells were determined by a senescence-associated-β-galactosidase(SA-β-gal) activity assay and cell cycle distribution was analyzed by flow cytometry. A Sybe Green real-time polymerase chain reaction(RT-PCR) method was used to examine the changes of expression profiles of 78 human cellular senescence-related genes. Results Cisplatin inhibited the proliferation of CNE2 cells in a dose- and time-dependent manner, and significantly induced a cellular senescence in CNE2 cells, which respectively counted at 67.63% of senescent cells at day 6 and 89.22% at day 8, after treatment with 1.0 mg/L of cisplatin. A G2/M phase arrest was observed. The expression levels of 16 senescence-related genes including TP53, TP63, p16Ink4a, p27Kip1, PTEN, RB1, TBX3, Cdc25C, Gadd45a, IGF1R, PIK3CA, MI-1, B2M, MORC3, MYC and SPARC were increased(P＜0.05 or 0.01), while the 14 genes including Cyclin A2, Cyclin B1, Cyclin E1,CDK6, ATM, E2F1, ETS1, ETS2, MDM2, FN1, IGFBP3, RBL2, SERPINB2 and SIRT1 were decreased at mRNA levels(P＜0.05 or 0.01). Conclusion Cisplatin could induce G2/M phase arrest and cellular senescence in CNE2 cells in vitro, which may involve a omplicated network of p53-pRb signaling or/and PTEN signaling pathways mediated by p16 and p27.