猪鼻支原体(Mycoplasma hyorhinis)诱导NCI-H446等小细胞肺癌细胞在FIGNL1沉默时出现S期阻滞

【目的】研究支原体对体外培养细胞基因功能的影响。【方法】利用si RNA抑制DNA双链损伤修复关键基因——FIGNL1在无支原体感染、感染猪鼻支原体及清除支原体污染后的人小细胞肺癌细胞株NCI-H446与NCI-H1688中的表达后,采用定量PCR、流式细胞术等方法检测支原体感染对宿主细胞目标基因表达、细胞周期等影响。【结果】虽然猪鼻支原体感染对si RNA沉默FIGNL1表达无显著影响,无支原体感染及清除支原体污染的H1688和H446细胞FIGNL1表达沉默后,与仅加转染试剂的空白组(mock)相比较,靶标FIGNL1基因的实验组(T1)和阴性对照组(nc)的S期细胞比例均未发生显著变化。但猪鼻支原体感染的H1688和H446细胞相对于空白组,实验组与阴性对照组的S期细胞比例,H1688细胞提高了约1.38倍和0.51倍,H446细胞提高了约1.27倍和0.55倍。【结论】推测由于支原体会对宿主细胞DNA造成损伤,而FIGNL1是DNA双链断裂损伤修复的重要基因,从而导致沉默猪鼻支原体感染的H1688和H446细胞FIGNL1表达时,细胞会出现S期阻滞。鉴于支原体感染对细胞有广泛、显著的影响,在基因功能、肿瘤等细胞生物学研究中,应予以高度重视。

Mycoplasma hyorhinis induces S phase arrest when suppressing expression of FIGNL1 in NCI-H446 and NCI-H1688 human small cell lung cancer cells

Objective] Effect of mycoplasma on gene function was studied in vitro. Methods] FIGNL1, a critical gene to repair DNA double-strand breaks, was suppressed by siRNA in H446 and H1688 cells infected with or without Mycoplasma hyorhinis or after mycoplasma removal. Expression of targeted gene and cell cycle analysis was measured using real-time PCR, flow cytometry and other methods. Results] No significant effect of M. hyorhinis was observed on the suppression of FIGNL1 expression by siRNA. After expression of FIGNL1 was suppressed in H1688 and H446 cells without Mycoplasma infection or after Mycoplasma removal, no significant change of cells proportion in S phase was observed between experimental group targeting FIGNL1 (T1) and negative control group compared with the blank group containing transfection reagent (mock). However, cell proportion in S phase of experimental and negative control group was increased approximately 1.38 and 0.51 folds, respectively comparing with blank group in H1688 cells infected with M. hyorhinis, 1.27 and 0.55 folds respectively in H446 cells infected with M. hyorhinis. Conclusion] When the expression of FIGNL1 was suppressed in H1688 and H446 cells, M. hyorhinis can significantly induce S phase arrest because Mycoplasma can cause host cells DNA damage and FIGNL1 is a critical gene to repair DNA double-strand breaks. Mycoplasma is widespread and significantly influential on cells, we should be highly alert to it on function study of gene and tumor research.