ABSTRACT

This study aims to investigate the overexpression-induced properties of tumor suppressor FAM134B (family with sequence similarity 134, member B) in colon cancer, examine the potential gene regulators of FAM134B expression and its impact on mitochondrial function. FAM134B was overexpressed in colon cancer and non-neoplastic colonic epithelial cells. Various cell-based assays including apoptosis, cell cycle, cell proliferation, clonogenic, extracellular flux and wound healing assays were performed. Western blot analysis was used to confirm and identify potential interacting partners of FAM134B in vitro. Immunohistochemistry and qPCR were employed to determine the expressions of MIF and FAM134B, respectively, on 63 patients with colorectal carcinoma. Results showed that FAM134B is involved in the cell cycle and mitochondrial function of colon cancer. Overexpression of FAM134B was coupled with increased expression levels of APC, p53, and MIF. Increased expression of both APC and p53 further validates the potential role of tumor suppressor FAM134B in regulating cancer progression through the WNT/ß-catenin signaling pathway. In approximately 70% of the patients with colorectal cancer, FAM134B downregulation was correlated with MIF protein overexpression while the remaining 30% showed concurrent expression of FAM134B and MIF (P = .045). High expression of MIF coupled with low expression of FAM134B is associated with microsatellite instability status in colorectal carcinomas (P = .049). FAM134B may exert its tumor suppressive function through affecting cell cycle, mitochondrial function via potentially interacting with MIF and p53.

摘要

本研究旨在研究肿瘤抑制因子FAM134B（序列相似性家族 134，成员 B）在结肠癌中的过表达诱导特性，检查FAM134B表达的潜在基因调节因子及其对线粒体功能的影响。FAM134B在结肠癌和非肿瘤性结肠上皮细胞中过度表达。进行了各种基于细胞的测定，包括细胞凋亡、细胞周期、细胞增殖、克隆形成、细胞外通量和伤口愈合测定。蛋白质印迹分析用于在体外确认和鉴定FAM134B 的潜在相互作用伙伴。采用免疫组化和qPCR检测MIF和FAM134B的表达分别针对 63 名结直肠癌患者。结果表明，FAM134B参与结肠癌的细胞周期和线粒体功能。FAM134B 的过度表达与 APC、p53 和 MIF 的表达水平增加有关。APC 和 p53 的表达增加进一步验证了肿瘤抑制因子FAM134B在通过 WNT/ß-catenin 信号通路调节癌症进展中的潜在作用。在大约 70% 的结直肠癌患者中，FAM134B下调与 MIF 蛋白过表达相关，而其余 30% 显示FAM134B和 MIF同时表达（P= .045）。MIF 的高表达加上FAM134B 的低表达与结直肠癌的微卫星不稳定性状态相关 ( P = .049)。FAM134B可能通过与 MIF 和 p53 潜在相互作用影响细胞周期、线粒体功能来发挥其肿瘤抑制功能。