Wu Xiao-Yu, Fang Jian, Wang Zhao-Jin, Chen Che, Liu Jia-Yun, Wu Guan-Nan, Yao Xue-Quan, Liu Fu-Kun, Zhou Xin
Department of Surgical Oncology, The Affiliated Hospital of Nanjing University of Chinese Medicine155 Hanzhong Road, Gulou District, Nanjing, China.
Department of General Surgery, Zhangjiagang Hospital Affiliated to Soochow University68 Jiyang Eastern Road, Zhangjiagang 215600, China.
Am J Cancer Res. 2017 Jun 1;7(6):1238-1251. eCollection 2017.
Development of cancer metastasis is a key contributor to mortality in patients with colorectal cancer. High expression of RING-box 2 (RBX2) in cancer cells is known to play a key role in tumor progression. However, the role of RBX2 in colorectal cancer progression is not well elucidated. In this study, we silenced RBX2 via CRISPR/Cas9 in two colorectal cancer cell lines, HCT116 and SW480. RBX2 knockout attenuated proliferation, colony formation and enhanced sensitivity of colorectal cancer cells to paclitaxel treatment. Invasive property of HCT116 and SW480 cells was also attenuated by RBX2 silencing. We confirmed that increased RBX2 correlated with higher tumor cells growth and metastasis abilities by ectopic expression of RBX2 in HCT116 and SW480 cells. In vivo studies suggested that knockout of RBX2 inhibited xenografts growth and metastasis to lung tissue, whereas ectopic expression of RBX2 promoted these cellular functions. Mechanically, RBX2 induced gastric cancer cell growth and metastasis by activating mammalian target of rapamycin/S6 kinase 1 (mTOR/S6K1). Treatment of everolimus, the specific mTOR inhibitor, significantly attenuated RBX2-mediated cell proliferation and mobility in vitro. Taken together, these results revealed a novel role of RBX2 in colorectal cancer cell growth and metastasis via the mTOR pathway and suggested RBX2 may serve as a therapeutic target in colorectal cancer.
癌症转移的发生是导致结直肠癌患者死亡的关键因素。已知癌细胞中RING盒蛋白2（RBX2）的高表达在肿瘤进展中起关键作用。然而，RBX2在结直肠癌进展中的作用尚未得到充分阐明。在本研究中，我们通过CRISPR/Cas9在两种结直肠癌细胞系HCT116和SW480中使RBX2沉默。RBX2基因敲除减弱了结直肠癌细胞的增殖、集落形成，并增强了其对紫杉醇治疗的敏感性。RBX2沉默也减弱了HCT116和SW480细胞的侵袭特性。我们通过在HCT116和SW480细胞中异位表达RBX2证实，RBX2的增加与更高的肿瘤细胞生长和转移能力相关。体内研究表明，RBX2基因敲除抑制了异种移植物的生长以及向肺组织的转移，而异位表达RBX2则促进了这些细胞功能。从机制上讲，RBX2通过激活雷帕霉素靶蛋白/核糖体蛋白S6激酶1（mTOR/S6K1）诱导胃癌细胞生长和转移。特异性mTOR抑制剂依维莫司治疗显著减弱了RBX2介导的体外细胞增殖和迁移能力。综上所述，这些结果揭示了RBX2通过mTOR途径在结直肠癌细胞生长和转移中的新作用，并表明RBX2可能成为结直肠癌的治疗靶点。
