Department of Pathology, The First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou, Hainan 571101, P.R. China.
Department of Gastrointestinal Surgery, Hainan Provincial People's Hospital, Haikou, Hainan 570311, P.R. China.
Int J Mol Med. 2018 Mar;41(3):1397-1408. doi: 10.3892/ijmm.2017.3345. Epub 2017 Dec 22.
Ras-related C3 botulinum toxin substrate 1 (RAC1) is a member of the Rho family of small GTPases. Recent studies have reported that RAC1 serves an important role in colon cancer cell proliferation. The present study aimed to investigate the effects of RAC1 knockdown on cell proliferation, cell cycle progression and apoptosis of colon cancer cells. Lentivirus‑mediated short hairpin RNA (shRNA) was used to knockdown RAC1 expression in colon cancer cell lines, and cell proliferation, apoptosis, cell cycle progression were evaluated by MTT assays and flow cytometry. The differences in mRNAs expression were identified between RAC1-knockdown cells and control cells using a mRNA microarray, following which quantitative PCR (qPCR) and western blot were employed to confirm the results of the mRNA microarray. The proliferative ability of colon cancer cells was significantly decreased following RAC1 knockdown, and RAC1 knockdown increased the apoptotic rate and enhanced cell cycle arrest at G1 phase in colon cancer cells. In addition, >1,200 known genes were demonstrated to be involved in RAC1‑associated tumorigenic functions in SW620 colon cancer cells, as determined by gene chip analysis; these genes were associated with cell proliferation, cell cycle, apoptosis and metastasis. Furthermore, western blot analysis indicated that cyclin D1 was downregulated, whereas B‑cell lymphoma 2‑associated agonist of cell death (BAD) was upregulated following RAC1 knockdown in colon cancer cells. In conclusion, RAC1 silencing may suppress the proliferation of colon cancer cells by inducing apoptosis and cell cycle arrest. In addition, a large number of genes were revealed to be involved in the process, including BAD, which was upregulated and cyclin D1, which was downregulated. Further studies on these differentially expressed genes may provide a better understanding of the potential roles of RAC1 in colon carcinogenesis.
Ras 相关 C3 肉毒梭菌毒素底物 1（RAC1）是 Rho 家族小 GTP 酶的成员。最近的研究表明，RAC1 在结肠癌细胞增殖中起重要作用。本研究旨在探讨 RAC1 敲低对结肠癌细胞增殖、细胞周期进程和凋亡的影响。慢病毒介导的短发夹 RNA（shRNA）用于敲低结肠癌细胞系中的 RAC1 表达，并通过 MTT 测定法和流式细胞术评估细胞增殖、细胞凋亡、细胞周期进程。使用 mRNA 微阵列鉴定 RAC1 敲低细胞与对照细胞之间的 mRNA 表达差异，随后使用定量 PCR（qPCR）和 Western blot 验证 mRNA 微阵列的结果。RAC1 敲低后结肠癌细胞的增殖能力显著降低，RAC1 敲低增加了结肠癌细胞的凋亡率，并增强了细胞周期停滞在 G1 期。此外，通过基因芯片分析，在 SW620 结肠癌细胞中，>1200 个已知基因被证明与 RAC1 相关的肿瘤发生功能有关；这些基因与细胞增殖、细胞周期、凋亡和转移有关。此外，Western blot 分析表明，RAC1 敲低后结肠癌细胞中细胞周期蛋白 D1 下调，而 B 细胞淋巴瘤 2 相关凋亡促进剂（BAD）上调。总之，RAC1 沉默可能通过诱导细胞凋亡和细胞周期停滞来抑制结肠癌细胞的增殖。此外，大量基因被揭示参与该过程，包括上调的 BAD 和下调的细胞周期蛋白 D1。对这些差异表达基因的进一步研究可能有助于更好地理解 RAC1 在结肠癌变中的潜在作用。
