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目的研究重组腺病毒第10号染色体同源丢失性磷酸酶张力蛋白基因(PTEN)对小细胞肺癌的抑癌增效和化疗增敏效应及其分子机制。方法采用重组腺病毒载体PTEN(简称Ad-PTEN)感染QBI-293A细胞,并用该细胞进行病毒扩增和效价测定。将Ad-PTEN感染NCI-H446小细胞肺癌细胞。分为5组:PBS组、空载体Ad组、Ad-PTEN组、顺铂(DDP)组和Ad-PTEN+DDP组,Western blot鉴定PTEN基因表达,MTT法和流式细胞仪(FCM)检测Ad-PTEN对NCI-H446小细胞肺癌细胞的生长抑制和诱导凋亡的增效作用,用RT-PCR检测细胞凋亡相关基因p53、bax、caspase-3、bcl-2、和survivin的转录。结果 Ad-PTEN可在QBI-293A细胞中增殖。Ad-PTEN感染NCI-H446细胞后,Western blot检测到了PTEN基因的表达。Ad-PTEN组、DDP组、Ad-PTEN+DDP组体外能明显抑制人NCI-H446小细胞肺癌细胞的生长和诱导凋亡,且Ad-PTEN+DDP组效应较Ad-PTEN组、DDP组更为显著(均P<0.05)。Ad-PTEN组、DDP组、Ad-PTEN+DDP组的NCI-H446细胞中的p53、bax及caspase-3基因表达均上调,而Bcl-2和Survivin基因表达均下调,这些凋亡相关基因的上调或下调的表达趋势以Ad-PTEN+DDP组最显著(均P<0.05)。结论 Ad-PTEN体外可抑制NCI-H446小细胞肺癌细胞生长,Ad-PTEN对DDP的细胞毒作用具有增敏效应,其机制可能与上调p53、bax及caspase-3基因表达和下调bcl-2和survivin基因表达有关。
Objective To study the antitumor and synergistic effects of PTEN on the small cell lung cancer and its molecular mechanism by the recombinant adenovirus on chromosome 10. Methods The recombinant adenovirus vector PTEN (Ad-PTEN) was used to infect QBI-293A cells, and the cells were used for virus amplification and titer determination. Ad-PTEN was infected in NCI-H446 small cell lung cancer cells. The cells were divided into five groups: PBS group, Ad-PTEN group, DDP group and Ad-PTEN + DDP group. PTEN gene expression was determined by Western blot, MTT assay and flow cytometry Ad-PTEN can inhibit the growth of NCI-H446 small cell lung cancer cells and induce apoptosis. The transcription of p53, bax, caspase-3, bcl-2 and survivin were detected by RT-PCR. Results Ad-PTEN can proliferate in QBI-293A cells. After Ad-PTEN infection of NCI-H446 cells, the expression of PTEN gene was detected by Western blot. Ad-PTEN group, DDP group and Ad-PTEN + DDP group could significantly inhibit the growth and induce apoptosis of human NCI-H446 small cell lung cancer cells in vitro, and the effect of Ad-PTEN + DDP group was more than that of Ad-PTEN group and DDP group (All P <0.05). The expression of p53, bax and caspase-3 in NCI-H446 cells in Ad-PTEN group, DDP group and Ad-PTEN + DDP group were up-regulated, while the expressions of Bcl-2 and Survivin were down-regulated The expression of up-regulated or down-regulated in Ad-PTEN + DDP group was the most significant (all P <0.05). Conclusions Ad-PTEN can inhibit the growth of NCI-H446 small cell lung cancer cells in vitro. Ad-PTEN can sensitize the cytotoxicity of DDP. The mechanism may be related to upregulation of p53, bax and caspase-3 gene expression and downregulation of bcl-2 and survivin gene expression.