Abstract:Objective To investigate the expression of PinX1 gene and its functional effects in human nasopharyngeal carcinoma (NPC) cells. Methods Expression vectors of human PinX1 (pEGFPC3PinX1) and its small interfering RNA (PinX1FAMsiRNA) were constructed and transfected into NPC 58F cells by lipofectamine TM 2000. First, mRNA level of PinX1 was examined with RTPCR. And then, its effects on mRNA level of telomerase catalytic subunit (hTERT), telomerase activity, cell proliferation and apoptosis were examined using semiquantitative RTPCR, stretch PCR, MTT assay and flow cytometry, respectively. Results The analysis of restriction and sequencing showed that the recombining plasmids were successfully constructed. The results also showed that transfection of pEGFPC3PinX1 and PinX1FAMsiRNA into NPC 58F cells increased PinX1 mRNA by 1.6fold and reduced PinX1 mRNA by 70%, respectively. Overexpression of PinX1 decreased hTERT mRNA by 29.9% (P<0.05), significantly reduced telomerase activity (P<0.05), inhibited cell growth, increased cell apoptotic index from 19.27%±0.76% to 49.73%±2.70%(P<0.05). The study further showed that silencing PinX1 did not alter all the characteristics of NPC 5-8F cells, including cell growth, mRNA level of hTERT, telomerase activity and cell apoptotic index (P>0.05). Conclusion Transfection of pEGFPC3PinX1 into NPC 58F cells can inhibit the expression of human telomerase activity and hTERT, decrease cell growth and induce apoptosis. Besides, inhibitory functions can’t work by silencing PinX1 with PinX1FAMsiRNA. Taking together, PinX1 as an endogenous telomerase inhibitor has application potential to tumortargeted gene therapy.
