目的：探究微小 RNA-504（miRNA-504）在胃癌（GC）组织中的表达水平及其对GC细胞生物学行为的调控机制。方法：收集2020年6月至2020年12月期间三亚中心医院外科收治的48例胃癌患者的肿瘤组织及癌旁组织标本，qPCR检测组织中 miR-504、肿瘤蛋白 53 诱导型核蛋白 1（tumor protein 53-induced nuclear protein 1，TP53INP1）mRNA 的水平 ，WB 法检测TP53INP1水平。体外培养人胃癌细胞 BGC-823，分为对照组（正常培养的 BGC-823细胞）、miR-504 mimic组、mimic-NC组、miR-504 inhibitor组、inhibitor-NC组、miR-504 inhibitor+si-NC组、miR-504 inhibitor+si-TP53INP1组，qPCR检测细胞中miR-504和TP53INP1 mRNA的表达，MTT法、流式细胞术、划痕实验和Transwell侵袭实验分别检测各组细胞的增殖、凋亡、迁移和侵袭能力，WB法检测各组细胞中增殖、迁移和侵袭相关蛋白（Cyclin D1、E-cadherin、MMP-2、MMP-9）以及TP53INP1的表达。双荧光素酶报告基因实验进一步验证miR-504与TP53INP1 mRNA的靶向关系。结果：与癌旁组织相比，胃癌组织中miR-504的表达显著升高（P<0.05），而TP53INP1 mRNA 和蛋白表达水平显著降低（P<0.05 或P<0.01），miR-504和TP53INP mRNA 两者的表达呈负相关（P<0.01）。与对照组相比，miR-504 mimic组BGC-823细胞中miR-504的表达显著升高（P<0.05）、TP53INP1 mRNA和蛋白的表达显著降低（均P<0.05），且细胞增殖率、划痕愈合率、侵袭入Transwell小室下层的细胞数量，Cyclin D1、MMP-2、MMP-9蛋白表达均显著增加，细胞凋亡率和E-cadherin蛋白表达均显著降低（均P<0.05）。转染miR-504 inhibitor能显著下调BGC-823中miR-504的表达、上调TP53INP1 mRNA和蛋白的表达，抑制细胞的增殖、迁移与侵袭能力而促进细胞凋亡（均P<0.05）；而下调TP53INP1的表达可明显减弱miR-504下调对BGC-823细胞增殖、迁移与侵袭的抑制作用（P<0.01）。miR-504高表达能明显抑制野生型TP53INP1质粒的荧光素酶活性（P<0.05）。结论：miR-504在胃癌组织中呈高表达，下调miR-504可抑制胃癌BGC-823细胞的恶性生物学行为而促进其凋亡，其作用机制可能与靶向调控TP53INP1的表达有关。

Objective: To explore the expression level of microRNA-504 (miRNA-504) in gastric cancer (GC) tissues and its regulatory mechanism in the biological behaviors of GC cells. Methods: From June 2020 to December 2020, tumor tissues and corresponding para-cancerous tissues resected from 48 patients with gastric cancer were collected in the Department of Surgical, Sanya Central Hospital. qPCR was used to detect the mRNA levels of miR-504 and tumor protein 53-induced nuclear protein 1 (TP53INP1) in the tissues, and WB assay was used to detect the protein level of TP53INP1. Human gastric cancer BGC-823 cells were cultured in vitro and divided into control group (normally cultured BGC-823 cells), miR-504 mimic group, mimic-NC group, miR-504 inhibitor group,inhibitor-NC group, miR-504 inhibitor+si-NC group, and miR-504 inhibitor+si-TP53INP1 group. qRT-PCR was used to detect mRNA expression of miR-504 and TP53INP1 in each group of cells. MTT method, Flow cytometry, Scratch test, and Transwell invasion assay were used to detect the proliferation, apoptosis, migration, and invasion of the cells in each group. WB assay was used to detect the protein expression of cell proliferation, migration, and invasion-related proteins (Cyclin D1, E-cadherin, MMP-2, MMP-9) and TP53INP1 in each group. Dual-luciferase reporter gene experiment was used to further verify the targeting relationship between miR[1]504 and TP53INP1. Results: Compared with the para-cancerous tissues, the expression of miR-504 in gastric cancer tissues was significantly increased (P<0.05), and the mRNA and protein expression levels of TP53INP1 were significantly decreased (P<0.05 or P <0.01). The expression of miR-504 was negatively correlated with TP53INP1 mRNA (P<0.01). Compared with the control group, the expression of miR-504 in the BGC-823 cells of the miR-504 mimic group was significantly increased, while the mRNA and protein expression of TP53INP1 was significantly decreased (all P<0.05); moreover, the cell survival rate, scratch healing rate, the number of cells entering the lower layer of the Transwell chamber, and the expression of Cyclin D1, MMP-2, and MMP-9 were all significantly increased, while the apoptosis rate and the expression of E-cadherin were significantly decreased (all P<0.05) in miR-504 mimic group;However, the miR-504 inhibitor could significantly down-regulate the expression of miR-504, up-regulate the mRNA and protein expression of TP53INP1, inhibit cell proliferation, migration, and invasion, and promote cell apoptosis (all P<0.05) in BGC-823 cells.Down-regulating the expression of TP53INP1 could significantly reduce the inhibitory effect of down-regulation of miR-504 on the proliferation, migration, and invasion of BGC-823 cells; and miR-504 over-expression could obviously inhibit the luciferase activity of wild-type TP53INP1 plasmid (all P<0.05). Conclusion: miR-504 is highly expressed in gastric cancer tissues. Down-regulation of miR[1]504 can inhibit the malignant biological behaviors of gastric cancer BGC-823 cells and promote their apoptosis, and the mechanism may be related to the targeted regulation of the expression of TP53INP1.

海南省卫生计生行业科研项目资助（No.16A200142）；三亚市医疗卫生科技创新项目资助（No.2017YW08）