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piRNAs是一类与Piwi蛋白家族相互作用的非编码小RNA。Piwi-piRNA通路的主要功能是调控生殖干细胞内转座子沉默,且该通路从果蝇到哺乳动物高度保守。然而,人乳腺癌干细胞中PIWI基因和piRNA的表达尚不明了。本研究采用流式细胞仪分选乳腺癌MCF-7细胞中的侧群细胞(SP)和非侧群的乳腺癌细胞(NSP),采用RT-PCR法及软琼脂克隆形成实验鉴定SP细胞的干细胞特性,采用实时荧光定量PCR法检测SP及NSP细胞中3种PIWI基因(HIWI,HILI和HIWI2)以及4种piRNA(piR-4987,piR-20365,piR-20485和piR-20582)的表达水平。结果显示:SP细胞亚群富含肿瘤干细胞样细胞;HIWI和HIWI2在SP细胞中的水平显著高于NSP细胞(p<0.05);piR-4987、piR-20365和piR-20582在SP细胞中的表达显著高于NSP细胞(p<0.01)。结果提示乳腺癌干细胞内可能存在类似生殖干细胞内的Piwi-piRNA通路,HIWI、HIWI2、piR-4987、piR-20365、piR-20485和piR-20582可能参与调控乳腺癌干细胞的生物学特性。
PiRNAs are a class of non-coding small RNAs that interact with the Piwi protein family. The main function of the Piwi-piRNA pathway is to regulate transposon silence in germline stem cells, and this pathway is highly conserved from Drosophila to Mammalian animals. However, the expression of PIWI genes and piRNAs in human breast cancer stem cells is not yet known. In this study, we used flow cytometry to classify side population cells (SPs) and non-side population breast cancer cells (NSPs) in breast cancer MCF-7 cells. RT-PCR and soft agar colony formation assays were used to identify SP cells The expression of three PIWI genes (HIWI, HILI and HIWI2) and four piRNAs (piR-4987, piR-20365, piR-20485 and piR-20582) in SP and NSP cells were detected by real- . The results showed that the SP cell subpopulation was rich in tumor stem cell-like cells; the HIWI and HIWI2 levels in SP cells were significantly higher than those in NSP cells (p <0.05); piR-4987, piR-20365 and piR- The expression was significantly higher than NSP cells (p <0.01). The results suggest that Piwi-piRNA pathway may exist in breast cancer stem cells like HIWI, HIWI2, piR-4987, piR-20365, piR-20485 and piR-20582 may be involved in the regulation of biological characteristics of breast cancer stem cells.