The Study Of CRTC2in Tumor Progress

CRTC2is a key protein modulating circulating glucose level. With the research of its current function limited in glucogenesis, I found it play a role in tumorgenesis.I first used shRNA to knockdown CRTC2in HepG2cells. Comparing the cell numbers of scramble and shRNA, knockdown of CRTC2significantly inhibits the proliferation of HepG2. Moreover, flow cytometry showed a significant decrease of Ki67positive cells after knockdowning CRTC2. Then I assorted the human liver cancer pathological biopsy into three groups based on the expression and activation of CRTC2. Among these specimens, Kaplan-Meier survival analysis revealed a correlation between higher CRTC2expression and activation levels and shorter overall survival times. Moreover, compared with LO2, several cancer cell lines such as HepG2、 HCT116、 A549also showed an upregulation and activation of CRTC2based on western blot results. Then we performed gene expression profiling on HepG2cells expressing either control shRNA or CRTC2shRNA grown in culture. Functional profiling of these genes revealed that the three genes of do novo serine synthesis pathway PHGDH、 SHMT2and PSAT1were significantly downregulated, specifically. Then we used quantitative RT-PCR to confirm CRTC2-dependent expression of the three genes identified in the microarray analysis. Moreover, with mRNA levels of glucose transporters unchanged after knocking down CRTC2, uptake of FITC-glucose remained the same based on flow cytometry results. Additional, lactic acid levels after two hour glucose incubation remained unchanged too. So we proposed that CRTC2might promote cancer cell proliferation through modulating serine synthesis pathway. Since CRTC2is the coactivator of CREB, we performed the same series of experiments on shCREB HepG2cells and the results are consistent with shCRTC2cells. Last, we injected scramble and shX cells into immune-deficient nude mice. Results showed that both formation and growth of tumor got inhibited.The relationship between cancer、 inflammation and metabolism has always been the hotspot of our biological research area. My research demonstrated that CRTC2functions through its activator CREB to activate de novo serine synthesis pathway thus promoting tumorgenesis. Objectively speaking, my research first revealed a new tumor promoting function of CRTC2. More importantly, based on previous research articles and my current work, CRTC2should be one of the linkage between cancer and metabolism, which will be a great breakthrough of cancer biology. Thus, CRTC2might be a more specific drug target for cancer prevention and therapy.