miR-let-7d通过调控核受体PPARγ促进肺癌细胞的增殖和侵袭

miR-let-7d regulates lung cancer cell proliferation and invasion abilities through nuclear receptor PPARγ

目的:探讨miR-let-7d对肺癌细胞核受体过氧化物酶体增殖物激活受体γ(PPARγ)的调控及对肺癌细胞增殖和侵袭的影响。方法:用生物信息学分析与PPARγ相关的microRNA,通过质粒报告基因验证miR-let-7d的作用靶点;利用Western blot法筛选出PPARγ表达水平低的肺癌细胞株;通过双萤光素酶标记和Western blot法验证miR-let-7d对肺癌细胞中PPARγ表达的调控作用;通过集落形成实验检测miR-let-7d对肺癌细胞增殖能力的调控作用;通过Transwell侵袭实验检测miR-let-7d对肺癌细胞侵袭能力的作用。结果:生物信息学的分析结果证明miR-let-7d可以调控核受体PPARγ的蛋白表达;在核受体PPARγ的3’UTR包含2个功能性的miR-let-7d结合位点;PPARγ是miR-let-7d的直接靶点,miR-let-7d可在蛋白和mRNA水平直接调控PPARγ的表达;miR-let-7d inhibitor通过升高PPARγ的表达促进肺癌细胞的增殖和侵袭能力。结论:miR-let-7d能够通过靶向增加具有抑癌作用的核受体PPARγ的表达水平,抑制肺癌细胞的增殖和侵袭能力。

AIM： To investigate the phenomenon that miR-let-7d regulates the proliferation and invasion abilities of the lung cancer cells through nuclear receptor peroxisome proliferator-activated receptors γ（ PPARγ）. METHODS：The relation between PPARγ and microRNA was analyzed by bioinformatics. The plasmid reporter assay was used to verify that PPARγ was the target of miR-let-7d. The lung cancer cell line with low expression of PPARγ was selected from different lung cancer cell lines by Western blot. The regulatory role of miR-let-7d in the lung cancer cells was determined by dual luciferase labeling and Western blot. The effect of miR-let-7d on the proliferation ability of lung cancer cells was detected by colony formation assay,the effect of miR-let-7d on the invasive ability of lung cancer cells was detected by Transwell invasion assay. RESULTS： The results of bioinformatic analysis showed that miR-let-7d regulated the expression of PPARγ,and the 3＇UTR of PPARγ contained 2 functional miR-let-7d binding sites,indicating that PPARγ is a direct target of miRlet-7d. miR-let-7d was able to directly regulate the expression of PPARγ at mRNA and protein levels. Transfection of miRlet-7d inhibitor promoted the proliferation and invasion abilities of lung cancer cells by increasing the expression of PPARγ.CONCLUSION： miR-let-7d increases the expression of tumor suppressor PPARγ to inhibit the proliferation and invasive abilities of lung cancer cells.