临床肿瘤学杂志

目的 探讨长链非编码RNA RP11-757G1.5对胃癌细胞生物学行为及顺铂敏感性的影响。方法 实时荧光定量PCR(RT-qPCR)检测胃上皮细胞GES-1和人胃癌细胞(MKN-45、NCI-N87、AGS和HGC-27)的RP11-757G1.5水平；设计并合成两条针对RP11-757G1.5的小干扰RNA(si RNA)序列(si-757G1.5#1与si-757G1.5#2)及阴性对照序列(si-NC)，将其分别转染至MKN-45和HGC-27细胞，设立Control组、si-NC组及两个干扰组(si-757G1.5#1和si-757G1.5#2)。为探究RP11-757G1.5对细胞生物学行为及药物敏感性的影响，分别采用细胞计数试剂盒-8(CCK-8)法检测细胞活力与顺铂的半数抑制浓度(IC₅₀)、划痕实验评估细胞迁移能力、Transwell实验分析细胞侵袭能力，并通过蛋白质印迹(Western blot)检测基质金属蛋白酶2和9(MMP-2和MMP-9)的蛋白表达水平。结果 RT-q PCR检测结果显示，与正常胃上皮细胞GES-1相比，RP11-757G1.5在多种胃癌细胞系中表达均显著上调(P<0.05)。选取其中表达水平最高的MKN-45和HGC-27细胞用于后续功能研究。在成功构建RP11-757G1.5敲低模型的基础上，CCK-8实验显示，与Control组和si-NC组相比，两个干扰组(si-757G1.5#1和si-757G1.5#2)的细胞增殖活力显著下降(P<0.05)；同时，基于CCK-8法的药物敏感性检测表明，干扰组对顺铂的化疗敏感性明显增强，IC₅₀值降低约2.3～2.7倍(P<0.05)。此外，划痕实验与Transwell实验结果显示，干扰组的细胞迁移与侵袭能力亦受到显著抑制，具体表现为划痕愈合率与穿膜细胞数均明显减少(P<0.05)。在机制层面，Western blot检测发现干扰组中MMP-2和MMP-9的蛋白表达水平均显著下调(P<0.05)。结论 RP11-757G1.5在胃癌中高表达，并通过调控MMP-2/9表达来促进肿瘤细胞的恶性表型，同时影响化疗敏感性，提示其可能成为胃癌治疗的新靶点。

Objective To explore the roles of long non-coding RNA RP11-757G1.5 in regulating biological behaviors and cisplatin sensitivity of gastric cancer cells.Methods The expression levels of RP11-757G1.5 in gastric epithelial cells(GES-1) and human gastric cancer cells(MKN-45,NCI-N87,AGS,and HGC-27) were detected by real-time quantitative PCR(RT-qPCR).Two small interfering RNA(siRNA) sequences targeting RP11-757G1.5(si-757G1.5#1 and si-757G1.5#2) and a negative control sequence(si-NC) were designed and synthesized,and then transfected into MKN-45 and HGC-27 cells.The cells were divided into Control,si-NC,and two interference groups(si-757G1.5#1 and si-757G1.5#2).To investigate the effects of RP11-757G1.5 on malignant behavior and drug sensitivity,the following experiments were performed:cell viability and the half-maximal inhibitory concentration(IC₅₀) of cisplatin were assessed using the Cell Counting Kit-8(CCK-8) assay;cell migration ability was evaluated by wound healing assay;cell invasion ability was analyzed by Trans well assay;and the protein expression levels of matrix metalloproteinase(MMP)-2/9 were detected by Western blot.Results RT-qPCR results showed that the expression of RP11-757G1.5 was significantly upregulated in various gastric cancer cell lines compared with the normal gastric epithelial cell line GES-1(P<0.05).The MKN-45 and HGC-27 cell lines,which exhibited the highest expression levels,were selected for subsequent functional studies.After successful establishment of RP11-757G1.5 knockdown models,a series of functional experiments were performed.The CCK-8 assay revealed that cell proliferation viability was significantly decreased in the two interference groups(si-757G1.5#1 and si-757G1.5#2) compared with the Control and si-NC groups(P<0.05).Meanwhile,drug sensitivity tests based on the CCK-8 method indicated that the interference groups exhibited significantly enhanced chemosensitivity to cisplatin,with IC₅₀ values decreased by approximately 2.3-2.7-fold(P<0.05).In addition,wound healing and Transwell assays demonstrated that the migration and invasion abilities of the cells were also significantly inhibited in the interference groups,as evidenced by markedly reduced wound closure rates and number of invading cells(P<0.05).At the mechanistic level,Western blot analysis showed that the protein expression levels of MMP-2 and MMP-9 were significantly downregulated in the interference groups(P<0.05).Conclusion RP11-757G1.5 is highly expressed in gastric cancer and promotes malignant phenotypes of tumor cells by regulating MMP-2 and MMP-9 expression,while also affecting chemotherapy sensitivity.These findings suggest its potential as a novel therapeutic target for gastric cancer.