Xu Lixia, Li Xiaoxing, Cai Muyan, Chen Jinna, Li Xiangchun, Wu William K K, Kang Wei, Tong Joanna, To Ka-Fai, Guan Xin-Yuan, Sung Joseph J Y, Chan Francis K L, Yu Jun
Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, Hong Kong Department of Gastroenterology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, Hong Kong State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China.
Gut. 2016 Apr;65(4):635-46. doi: 10.1136/gutjnl-2014-308257. Epub 2015 May 6.
Using whole genome sequencing, we identified gene amplification of solute carrier family 12 member 5 (SLC12A5) located at 20q13.12 in colorectal cancer (CRC). We analysed its amplification, overexpression, biological effects and prognostic significance in CRC.
SLC12A5 amplification status was evaluated by fluorescence in situ hybridisation (FISH). The effects of SLC12A5 re-expression or knockdown were determined in proliferation, apoptosis, invasion and metastasis assays. SLC12A5 target genes and related pathways were identified by reporter activity and cDNA microarray analyses. Clinical impact of SLC12A5 overexpression was assessed in 195 patients with CRC.
Amplification of SLC12A5 was verified in 78 out of 191 (40.8%) patients with primary CRC by FISH, which was positively correlated with its protein overexpression (p<0.001). Biofunctional investigation of SLC12A5 revealed that SLC12A5 significantly increased cell proliferation, G1-S cell cycle transition, invasion/migration abilities, but suppressed apoptosis in vitro and promoted xenograft tumour growth as well as lung metastasis in vivo. The antiapoptosis effect by SLC12A5 was mediated through inhibiting apoptosis-inducing factor and endonuclease G-dependent apoptotic signalling pathway; and the pro-metastasis role was by regulating key elements of the matrix architecture, including matrix metallopeptidase and fibronectin. After a median follow-up of 50.16 months, multivariate analysis revealed that patients with SLC12A5 protein overexpression had a significant decrease in overall survival. Kaplan-Meier survival curves showed that SLC12A5 overexpression was significantly associated with shortened survival in patients with CRC.
SLC12A5 plays a pivotal oncogenic role in colorectal carcinogenesis; its overexpression is an independent prognostic factor of patients with CRC.
通过全基因组测序，我们在结直肠癌（CRC）中鉴定出位于20q13.12的溶质载体家族12成员5（SLC12A5）基因扩增。我们分析了其在CRC中的扩增、过表达、生物学效应及预后意义。
通过荧光原位杂交（FISH）评估SLC12A5的扩增状态。在增殖、凋亡、侵袭和转移实验中确定SLC12A5重新表达或敲低的效果。通过报告基因活性和cDNA微阵列分析鉴定SLC12A5靶基因及相关途径。在195例CRC患者中评估SLC12A5过表达的临床影响。
通过FISH在191例原发性CRC患者中的78例（40.8%）中验证了SLC12A5的扩增，这与其蛋白过表达呈正相关（p<0.001）。对SLC12A5的生物功能研究表明，SLC12A5显著增加细胞增殖、G1-S细胞周期转换、侵袭/迁移能力，但在体外抑制凋亡，并在体内促进异种移植肿瘤生长及肺转移。SLC12A5的抗凋亡作用是通过抑制凋亡诱导因子和核酸内切酶G依赖性凋亡信号通路介导的；其促转移作用是通过调节基质结构的关键成分，包括基质金属蛋白酶和纤连蛋白。中位随访50.16个月后，多变量分析显示SLC12A5蛋白过表达的患者总生存期显著降低。Kaplan-Meier生存曲线显示，SLC12A5过表达与CRC患者生存期缩短显著相关。
SLC12A5在结直肠癌发生中起关键致癌作用；其过表达是CRC患者的独立预后因素。
