Background: MicroRNAs (miRNAs), a class of small-regulatory RNA molecules, were closely involved in the pathogenesis of a broad-spectrum of colorectal cancer (CRC). But role of miR-147b in CRC still remains unclear. Methods: Real-time RT-PCR or Western blotting was utilized to detect the expressions of miR-147b and RAP2B in CRC cell lines and tissues. Luciferase reporter assays were conducted to detect the associations between miR-147b and 3′UTRs of RAP2B. A series of assays were performed to evaluate the effect of miR-147b on proliferation, migration, and invasion of CRC in vitro and in vivo. Results: We found that the level of miR-147b was significantly lower in CRC tissues than in normal tissues (p = 0.0006). Enforced expression of miR-147b led to suppression of CRC cell proliferation in vitro and tumor growth in vivo. Specifically, miR-147b promoted proliferation by arresting CRC cells in the G1/G0 phase. Mechanically, RAP2B was identified as a direct target gene of miR-147b and RAP2B rescued the suppression of proliferation and invasion reduced by miR-147b in CRC cells. Conclusions: miR-147b not only plays important roles in the regulation of cell proliferation and tumor growth in CRC, which might be a potential prognostic marker or therapeutic target for CRC.

中文翻译：

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MicroRNA-147b 通过靶向 RAS 癌基因家族 (RAP2B) 促进人类结直肠癌的增殖和侵袭

背景：微小RNA（miRNA）是一类小分子调节RNA，与广谱结直肠癌（CRC）的发病机制密切相关。但 miR-147b 在 CRC 中的作用仍不清楚。方法：采用实时RT-PCR或Western blotting检测CRC细胞系和组织中miR-147b和RAP2B的表达。进行荧光素酶报告基因检测以检测 miR-147b 与 RAP2B 的 3'UTR 之间的关联。进行了一系列测定以评估 miR-147b 在体外和体内对 CRC 增殖、迁移和侵袭的影响。结果：我们发现 CRC 组织中 miR-147b 的水平显着低于正常组织（p = 0.0006）。miR-147b 的强制表达导致体外 CRC 细胞增殖和体内肿瘤生长的抑制。具体来说，miR-147b 通过在 G1/G0 期阻止 CRC 细胞来促进增殖。在机械上，RAP2B 被鉴定为 miR-147b 的直接靶基因，RAP2B 挽救了 CRC 细胞中 miR-147b 减少的增殖和侵袭抑制。结论：miR-147b不仅在CRC细胞增殖和肿瘤生长调控中发挥重要作用，可能成为CRC的潜在预后标志物或治疗靶点。