Zhou Xiaohua, Chen Wenqiang, Zhuang Duanming, Xu Guangqi, Puyang Yongqiang, Rui Hongqing
Department of General Surgery, Nanjing Gaochun People's Hospital, Gaochun, 211300, Jiangsu, China.
Department of Medical Oncology, Nanjing Gaochun People's Hospital, Gaochun, 211300, Jiangsu, China.
Biochem Genet. 2025 Apr;63(2):1924-1937. doi: 10.1007/s10528-024-10766-w. Epub 2024 Apr 19.
SET domain-containing 5 (SETD5), a member of protein lysine methyltransferase family, is expressed in multiple cancers, making it potential therapeutic targets. However, the role of SETD5 in colorectal cancer remains largely unknown. The expression of SETD5 in the 30 pairs colorectal cancer tissues samples and cell lines were determined by qRT-PCR. The functions of SETD5 was detected by knocked-down or overexpression in colorectal cancer cell lines SW480 and HCT116 cells. Cell proliferative activity, cell death, and stemness characteristics were assessed. BEZ235, a PI3K/AKT/mTOR pathway inhibitor, was used to perform rescue experiment to analyze whether SETD5 exerted its effects through activating PI3K/AKT/mTOR pathway. SETD5 was substantially upregulated in colorectal cancer, and correlated to metastasis and clinical stage of patients. Knockdown of SETD5 inhibited SW480 and HCT116 cell growth, as evidenced by the inhibition of cell viability and clone-forming. Moreover, Knockdown of SETD5 suppressed the capability of tumor sphere formation of SW480 and HCT116 cells, and reduced the expression of stemness-related proteins Nanog and Sox2. Further western blot analysis revealed that SETD5 knockdown inhibited the phosphorylation of proteins associated with the PI3K/AKT/mTOR pathway. In contrast, overexpression of SETD5 exerted the opposite effects. Mechanistically, by blocking PI3K/AKT/mTOR pathway with BEZ235, the effects of SETD5 overexpression on cell viability and Nanog and Sox2 protein expression were reversed. Our results substantiated that SETD5 functioned as an oncogene by promoting cell growth and stemness in colorectal cancer cells through activating the PI3K/AKT/mTOR signaling pathway.
含SET结构域蛋白5（SETD5）是蛋白质赖氨酸甲基转移酶家族的成员之一，在多种癌症中均有表达，这使其成为潜在的治疗靶点。然而，SETD5在结直肠癌中的作用仍不清楚。采用qRT-PCR检测30对结直肠癌组织样本及细胞系中SETD5的表达。通过在结直肠癌细胞系SW480和HCT116细胞中敲低或过表达来检测SETD5的功能。评估细胞增殖活性、细胞死亡及干性特征。使用PI3K/AKT/mTOR通路抑制剂BEZ235进行挽救实验，以分析SETD5是否通过激活PI3K/AKT/mTOR通路发挥作用。SETD5在结直肠癌中显著上调，且与患者的转移和临床分期相关。敲低SETD5可抑制SW480和HCT116细胞生长，细胞活力和克隆形成受到抑制即可证明。此外，敲低SETD5可抑制SW480和HCT116细胞形成肿瘤球的能力，并降低干性相关蛋白Nanog和Sox2的表达。进一步的蛋白质印迹分析显示，敲低SETD5可抑制与PI3K/AKT/mTOR通路相关蛋白的磷酸化。相反，过表达SETD5则产生相反的效果。机制上，用BEZ235阻断PI3K/AKT/mTOR通路后，SETD5过表达对细胞活力以及Nanog和Sox2蛋白表达的影响被逆转。我们的结果证实，SETD5在结直肠癌细胞中通过激活PI3K/AKT/mTOR信号通路促进细胞生长和干性，发挥癌基因的作用。
