Cheng Qian, Tong Tan-Jun, Li Zhao, Hu Shi-Hua, Chen Ding-Bao, Wang Si-Qi, Zhu Ji-Ye
Peking University Institute of Organ Transplantation, Peking University Center of Liver Cancer Diagnosis and Treatment, Beijing Key Surgical Basic Research Laboratory of Liver Cirrhosis and Liver Cancer, Department of Hepatobiliary Surgery, Peking University People's Hospital, Beijing, 100044, China,
Peking University Research Center on Aging, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China.
Onco Targets Ther. 2019 Mar 15;12:2035-2046. doi: 10.2147/OTT.S188449. eCollection 2019.
Cellular senescence-inhibited gene (CSIG) strongly prolongs the progression of replicative senescence. However, roles and mechanisms of CSIG in tumor progression have not been studied widely.
Roles of CSIG in migration and proliferation of SMMC7721 and Huh7 cells were analyzed by transwell or cell viability assays, respectively. Tumorigenicity assays were used to study whether CSIG knockdown could affect SMMC7721 proliferation in vivo. Next, Western blotting and RT-PCR were preformed to evaluate the effects of CSIG on P-ERK cascade and epithelial mesenchymal transformation markers. Then, the location and expression of CSIG protein was detected by immunofluorescence and Western blotting, respectively. Finally, the Cancer Genome Atlas dataset was used to analyze CSIG mRNA levels in hepatocellular carcinoma (HCC) and adjacent non-tumor tissues.
In this study, we found that CSIG overexpression promoted SMMC7721 cell migration, and CSIG knockdown suppressed tumorigenicity of SMMC7721 cells. In contrast to expectation, CSIG up-regulation could significantly inhibit Huh7 cell growth and migration. CSIG could promote P-ERK activation and levels of mesenchymal-like markers in SMMC7721 cells, whereas CSIG suppressed P-ERK activation and levels of mesenchymal-like markers in Huh7 cells. CSIG protein was located in nucleoli as well as nucleoplasm of SMMC7721 cells, whereas CSIG protein was mainly expressed in the nucleoli rather than nucleoplasm of Huh7 cells. Finally, due to individual differences, raised or down-regulated trends of CSIG in HCC as compared with adjacent non-tumor tissues are different among various patient populations.
In summary, these results indicate that CSIG might play different roles in SMMC7721 and Huh7 cells through regulating P-ERK pathway and mesenchymal-like markers. The differential distribution of CSIG might be an important factor that causes its different functions in SMMC7721 and Huh7 cells. CSIG might play different roles in various patient populations.
细胞衰老抑制基因（CSIG）能显著延长复制性衰老进程。然而，CSIG在肿瘤进展中的作用和机制尚未得到广泛研究。
分别通过Transwell实验或细胞活力检测分析CSIG对SMMC7721和Huh7细胞迁移和增殖的作用。采用致瘤性实验研究CSIG敲低是否会影响SMMC7721细胞在体内的增殖。接下来，进行蛋白质免疫印迹法（Western blotting）和逆转录-聚合酶链反应（RT-PCR）以评估CSIG对P-ERK级联反应和上皮-间质转化标志物的影响。然后，分别通过免疫荧光和蛋白质免疫印迹法检测CSIG蛋白的定位和表达。最后，利用癌症基因组图谱数据集分析肝细胞癌（HCC）和癌旁非肿瘤组织中CSIG mRNA水平。
在本研究中，我们发现CSIG过表达促进SMMC7721细胞迁移，而CSIG敲低抑制SMMC7721细胞的致瘤性。与预期相反，CSIG上调可显著抑制Huh7细胞生长和迁移。CSIG可促进SMMC7721细胞中P-ERK激活及间充质样标志物水平，而CSIG抑制Huh7细胞中P-ERK激活及间充质样标志物水平。CSIG蛋白位于SMMC7721细胞的核仁和核质中，而CSIG蛋白主要在Huh7细胞的核仁而非核质中表达。最后，由于个体差异，不同患者群体中HCC与癌旁非肿瘤组织相比，CSIG的上调或下调趋势有所不同。
总之，这些结果表明CSIG可能通过调节P-ERK途径和间充质样标志物在SMMC7721和Huh7细胞中发挥不同作用。CSIG的差异分布可能是导致其在SMMC7721和Huh7细胞中发挥不同功能的重要因素。CSIG可能在不同患者群体中发挥不同作用。
