目的：探讨miR-17-5p在胃肠道间质瘤（gastrointestinal stromal tumor，GIST）组织中的表达及其对GIST882细胞增殖 与凋亡的影响。方法：选取2019年5月至2020年5月广西医科大学第四附属医院胃肠外科手术切除的20例GIST患者的瘤组织 及相应的瘤旁组织标本，以及GIST882细胞和人正常肠道上皮细胞HIEC为研究对象。荧光PCR-毛细管电泳测序法检测GIST 标本中KIT基因突变情况。分别将 miR-17-5p mimic 和 pc-KIT 转染至 GIST882 细胞中。双荧光素酶报告基因实验验证 miR-17-5p与KIT的靶向关系。qPCR和WB法检测GIST组织和细胞中miR-17-5p、KIT mRNA及蛋白的表达，CCK-8法、流式细 胞术检测GIST882细胞的增殖、凋亡及细胞周期进程。结果：20例GIST组织中有15例患者发生KIT基因突变。与瘤旁组织比 较，GIST组织中miR-17-5p表达水平显著降低、KIT mRNA表达水平显著升高（均P<0.01)；与HIEC细胞比较，GIST882细胞中 miR-17-5p表达显著降低、KIT mRNA和蛋白表达显著升高（均P<0.01)。过表达miR-17-5p可显著降低GIST882细胞的增殖能力(P<0.01) 、提高细胞凋亡率(P<0.05) 、sub-G1期和S期细胞比例显著增加（均P<0.05) 、而G0/G1期的细胞比例显著减少(P<0.05)，同时KIT 蛋白表达水平明显降低(P<0.01)。双荧光素酶报告基因实验证实KIT是miR-17-5p的下游靶基因。同时过表达 miR-17-5p 和 KIT 对 GIST882 细胞的增殖、细胞周期进程和凋亡水平未产生明显影响。结论：过表达 miR-17-5p 可显著抑制 GIST882细胞的增殖并诱导细胞凋亡，同时下调KIT蛋白的表达，miR-17-5p可能是治疗GIST的潜在靶标。

Objective: To investigate the expression of miR-17-5p in gastrointestinal stromal tumor (GIST) tissues and its effect on proliferation and apoptosis of GIST882 cells. Methods: Twenty pairs of GIST tissues and corresponding paratumoral tissues form patients who underwent gastrointestinal surgery in the Fourth Affiliated Hospital of Guangxi Medical University from May 2019 to May 2020 were selected for this study; at the same time, GIST882 cells and human intestinal epithelial cells (HIECs) were also collected for this study. The KIT gene mutations in GIST tissue samples were detected by fluorescence PCR-capillary electrophoresis sequencing. The miR-17-5p mimics and pc-KIT plasmids were transfected into GIST882 cells, respectively. The targeting relationship between miR-17-5p and KIT was verified by Dual-luciferase reporter gene assay. The mRNA and protein expressions of miR-17-5p and KIT in GIST tissues and GIST882 cells were detected by qPCR and WB, respectively; and the proliferation, apoptosis and cell cycle progression of the cells were detected by CCK-8 and Flow cytometry. Results: KIT gene mutations occurred in 15 GIST patients (15/20). Compared with paratumoral tissues, miR-17-5p expression was significantly decreased while KIT mRNA expression was significantly increased in GIST tissues (all P<0.01); compared with HIEC cells, miR-17-5p expression was significantly decreased while mRNA and protein expressions of KIT were significantly increased in GIST882 cells (all P<0.01). Overexpression of miR-17-5p significantly decreased the proliferation ability and increased the apoptosis rate of GIST882 cells (P<0.01 or P<0.05), increased the proportion of cells in sub-G1 and S phases (P<0.05), and decreased the expression level of KIT protein (P<0.01). Dual-luciferase reporter gene assay confirmed that KIT is a downstream target gene of miR-17-5p. Simultaneous overexpression of miR-17-5p and KIT did not produce significant effects on the proliferation, cell cycle progression and apoptotic levels of GIST882 cells. Conclusion: Overexpression of miR-17-5p can significantly inhibit the proliferation and induce apoptosis of GIST882 cells and downregulate the expression of KIT protein. miR-17-5p may be a potential target in the treatment of GIST.

广西壮族自治区卫生健康委员会自筹经费科研课题资助项目（No.Z2016176, No. Z20190443 ）