The suppressive effects of miR-33a-5p have been reported in colorectal cancer and lung cancer. However, the functional role of miR-33a-5p in pancreatic ductal adenocarcinoma (PDAC) has not yet been elucidated. The expression of miR-33a-5p was determined using reverse-transcription quantitative PCR (RT-qPCR) in PDAC tissues and cell lines. The association between miR-33a-5p expression and clinical categorical parameters was analyzed by the chi-square test. Cell proliferation was analyzing by Cell Counting Kit -8 (CCK-8) assay. Transwell assay was utilized to assess cell migration and invasion. The interactions between miR-33a-5p and RAP2A were verified by luciferase reporter assay, RT-qPCR, western blot analysis and RNA immunoprecipitation (RIP) assay. Here, we observed for the first time that miR-33a-5p expression level was significantly decreased in PDAC tissues and cell lines. There was a significant association between decreased miR-33a-5p expression and TNM stage or lymph node metastasis. Overexpression of miR-33a-5p significantly inhibited SW1990 and PANC-1 cell proliferation, migration and invasion. Knockdown of miR-33a-5p remarkedly promoted cell proliferation, migration and invasion in BxPC-3 and ASPC-1. Mechanistically, RAP2A was confirmed as the target of miR-33a-5p in PDAC cells. Moreover, RAP2A overexpression abolished miR-33a-5p-mediated suppressive effects on SW1990 and PANC-1 cells. Taken together, these results suggest that miR-33a-5p exerted tumor suppressive effects on PDAC cells by targeting RAP2A, which might provide a new theoretical basis for the clinical treatment of PDAC.

中文翻译：

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miR-33a-5p通过直接靶向RAP2A对胰腺导管腺癌细胞的抑癌作用

已经报道了 miR-33a-5p 在结直肠癌和肺癌中的抑制作用。然而，miR-33a-5p 在胰腺导管腺癌 (PDAC) 中的功能尚未阐明。使用逆转录定量 PCR (RT-qPCR) 在 PDAC 组织和细胞系中测定 miR-33a-5p 的表达。通过卡方检验分析 miR-33a-5p 表达与临床分类参数之间的关联。通过细胞计数试剂盒-8(CCK-8)测定法分析细胞增殖。Transwell 测定用于评估细胞迁移和侵袭。miR-33a-5p 和 RAP2A 之间的相互作用通过荧光素酶报告基因测定、RT-qPCR、蛋白质印迹分析和 RNA 免疫沉淀 (RIP) 测定验证。这里，我们首次观察到 PDAC 组织和细胞系中 miR-33a-5p 的表达水平显着降低。miR-33a-5p 表达降低与 TNM 分期或淋巴结转移之间存在显着关联。miR-33a-5p的过表达显着抑制SW1990和PANC-1细胞增殖、迁移和侵袭。敲除 miR-33a-5p 显着促进 BxPC-3 和 ASPC-1 中的细胞增殖、迁移和侵袭。从机制上讲，RAP2A 被确认为 PDAC 细胞中 miR-33a-5p 的靶标。此外，RAP2A 过表达消除了 miR-33a-5p 介导的对 SW1990 和 PANC-1 细胞的抑制作用。综上所述，这些结果表明miR-33a-5p通过靶向RAP2A对PDAC细胞发挥抑癌作用，可能为PDAC的临床治疗提供新的理论基础。