摘要
目的:探究长链非编码RNA母系表达基因8(LncRNA MEG8)通过靶向miR-15a-5p调控MHCⅠ类相关蛋白A/B(MICA/B)介导的结直肠癌(CRC)细胞免疫逃逸机制.方法:RT-qPCR、Western blot检测CRC组织和细胞系MEG8、miR-15a-5p、MICA、MICB、NKG2D蛋白水平;双荧光素酶实验验证MEG8对miR-15a-5p的调控关系;采用脂质体转染法将NC、MEG8、miR-NC、miR-15a-5p分别或共转染至SW480、SW620细胞,记为NC组、MEG8组、MEG8+miR-NC组、MEG8+miR-15a-5p组;将NK细胞分别与SW480、SW620细胞共培养;ELISA检测共培养液中TNF-α、IFN-γ水平;CCK-8、EdU染色、Transwell实验检测细胞增殖、迁移和侵袭能力;RT-qPCR、Western blot检测细胞MEG8、miR-15a-5p、MICA、MICB、NKG2D蛋白水平.结果:与癌旁组织或正常结肠上皮细胞相比,CRC组织和细胞系中MEG8、MICA、MICB、NKG2D mRNA和蛋白水平降低,miR-15a-5p水平升高(P<0.05).MEG8靶向调控miR-15a-5p.共培养体系中,与NC组相比,MEG8组细胞MICA、MICB、NKG2D蛋白水平、共培养上清液中TNF-α、IFN-γ水平明显升高,培养1 d、2 d、3 d后,OD值、EdU阳性率、迁移和侵袭细胞数明显降低(P<0.05);过表达miR-15a-5p能部分逆转过表达MEG8对细胞MICA、MICB、NKG2D、TNF-α、IFN-γ水平和增殖、侵袭转移能力的影响(P<0.05).结论:MEG8通过靶向miR-15a-5p调控MICA、MICB表达,促进NK细胞活性,抑制CRC细胞免疫逃逸.
Abstract
Objective:To explore mechanism of long non-coding RNA maternally expressed gene 8(LncRNA MEG8)mediates immune escape in colorectal cancer(CRC)cells by regulating MICA/B via targeting miR-15a-5p.Methods:RT-qPCR and Western blot were used to detect expressions of MEG8,miR-15a-5p,MICA,MICB,NKG2D protein in CRC tissue and cell lines;dual luciferase experiment was used to verify regulatory relationship of MEG8 on miR-15a-5p;NC,MEG8,miR-NC and miR-15a-5p were respectively or co-transfected into SW480 and SW620 cells by liposome transfection,and recorded as NC group,MEG8 group,MEG8+miR-NC group,MEG8+miR-15a-5p group;NK cells were cocultured with SW480 and SW620 cells respectively;ELISA was used to detect TNF-α and IFN-γ levels in coculture medium;CCK-8,EdU staining,Transwell assay were used to detect cell prolifera-tion,migration and invasion ability;RT-qPCR and Western blot were used to detect MEG8,miR-15a-5p,MICA,MICB,NKG2D protein levels in cells.Results:Compared with adjacent cancer tissues or normal colon epithelial cells,MEG8,MICA,MICB,NKG2D mRNA and protein levels in CRC tissues and cell lines were decreased,while miR-15a-5p level was increased(P<0.05).MEG8 targeting regulated miR-15a-5p.In cocultivation system,compared with NC group,MICA,MICB,NKG2D protein levels,TNF-α,IFN-γ levels in cocultured supernatant in MEG8 group were significantly increased,after 1 d,2 d,and 3 d of cell culture,OD value,EdU positive rate,number of migrating and invading cells were significantly decreased(P<0.05);overexpression of miR-15a-5p could partially reverse effects of overexpression of MEG8 on MICA,MICB,NKG2D,TNF-α,IFN-γ levels in cells,prolifera-tion,invasion and metastasis ability(P<0.05).Conclusion:MEG8 promotes NK cell activity and inhibits CRC cell immune escape by regulating MICA and MICB expressions via targeting miR-15a-5p.
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