Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.
Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, Hunan, China.
J Cell Physiol. 2020 Jan;235(1):442-453. doi: 10.1002/jcp.28984. Epub 2019 Jul 22.
Colorectal cancer (CRC) is commonly known as one of the most prominent reasons for cancer-related death in China. Ras homolog enriched in brain (RHEB) and the mammalian target activity of rapamycin (mTOR) signaling pathway were found correlated with CRC, but their specific interaction in CRC was still to be investigated. Therefore, we explored whether RHEB gene silencing affected the cell proliferation, differentiation, and apoptosis by directly targeting the mTOR signaling pathway in cells previously harvested from CRC patients. A microarray analysis was subsequently conducted to investigate the relationship between RHEB and mTOR. Eighty-three adjacent normal tissues and CRC tissues were selected. Immunohistochemistry was carried out to detect the positive expression rates of RHEB and Ki-67 in the CRC tissues. Cells were then transfected with different siRNAs to investigate the potential effects RHEB would have on CRC progression. The expressions of RHEB, 4EBP1, ribosomal protein S6 kinase (p70S6K), proliferating cell nuclear antigen (PCNA), B cell lymphoma 2 (bcl-2), and bcl-2-associated X protein (bax) were determined and then the cell cycle, cell proliferation, and apoptotic rate were also measured. We identified RHEB and mTOR as upregulated genes in CRC. Cells treated with RHEB silencing showed a decreased extent of mTOR, p70S6K, 4EBP1 phosphorylation and expression of RHEB, Ki-67, mTOR, p70S6K, 4EBP1, bcl-2, and PCNA as well as decreased activity of cell proliferation and differentiation; although, the expression of bax was evidently higher. Collectively, our data propose the idea that RHEB gene silencing might repress cell proliferation and differentiation while accelerating apoptosis via inactivating the mTOR signaling pathway.
结直肠癌（CRC）是中国癌症相关死亡的主要原因之一。Ras 同源物富集在脑中（RHEB）和哺乳动物雷帕霉素靶蛋白（mTOR）信号通路与 CRC 相关，但它们在 CRC 中的具体相互作用仍有待研究。因此，我们通过直接靶向从 CRC 患者中分离的细胞中的 mTOR 信号通路，研究了 RHEB 基因沉默是否会影响细胞增殖、分化和凋亡。随后进行了微阵列分析以研究 RHEB 和 mTOR 之间的关系。选择了 83 个相邻正常组织和 CRC 组织。进行免疫组织化学检测以检测 CRC 组织中 RHEB 和 Ki-67 的阳性表达率。然后用不同的 siRNA 转染细胞，以研究 RHEB 对 CRC 进展的潜在影响。检测 RHEB、4EBP1、核糖体蛋白 S6 激酶（p70S6K）、增殖细胞核抗原（PCNA）、B 细胞淋巴瘤 2（bcl-2）和 bcl-2 相关 X 蛋白（bax）的表达，并测量细胞周期、细胞增殖和凋亡率。我们发现 RHEB 和 mTOR 在 CRC 中上调。用 RHEB 沉默处理的细胞显示 mTOR、p70S6K、4EBP1 磷酸化和 RHEB、Ki-67、mTOR、p70S6K、4EBP1、bcl-2 和 PCNA 的表达减少，细胞增殖和分化活性降低；然而，bax 的表达明显更高。总的来说，我们的数据表明 RHEB 基因沉默可能通过使 mTOR 信号通路失活来抑制细胞增殖和分化，同时加速细胞凋亡。
