GLDC Regulated Ubiquitination Of Cofilin Affects Hepatocellular Carcinoma Metastasis And Prognosis

Hepatocellular carcinoma(HCC)is a malignant tumor with high malignancy,low cure rate and poor prognosis.It has become the second-leading cause of cancer deaths in China.How to inhibit the recurrence and metastasis of HCC in order to improve the patient’s overall survival time has become the focus of research worldwide.In recent years,with the development of cancer research,metabolic reprogramming has become a new hallmark of cancer.Glycine decarboxylase(GLDC),an oxidoreductase,plays an important role in amino acid metabolism.GLDC promotes tumor initiation and proliferation in non-small cell lung cancer.However,it was reported as a putative tumor suppressor gene in gastric cancer,the role of GLDC in hepatocellular carcinoma(HCC)is unknown.In the current study,microarray-based analysis suggested that GLDC expression was low in highly malignant HCC cell lines.GLDC expression levels of HCC cancer tissues and paracancerous tissues were detected by qRT-PCR,Western blot and immunohistochemical staining.The results revealed a decrease in GLDC in HCC cancer samples.Clinicopathological data analysis showed that low GLDC levels in HCC cancer tissues were related with massive type tumor,lymph nodes metastasis,higher BCLC stage and TNM stage.Patients with lower tumor GLDC level had poor prognosis.GLDC expression level can be used as an independent risk factor for the prognosis of HCC patients.By constructing GLDC downregulated and over expressed stable cell lines,we used Transwell assay,wound healing assay and chemotaxis assay,as well as in situ intrahepatic metastasis model in nude mice,we found that GLDC could inhibit the invasion and metastasis of HCC cells in vivo and in vitro.Through the study of cytoskeleton,it was found that GLDC can inhibit cytoskeletal remodeling and inhibit cell protrusion formation by inhibiting Slingshot homolog 1(SSH1)-cofilin pathway,thereby inhibiting HCC cell migration.On the other hand,mechanistic studies revealed that GLDC decreased the levels of reactive oxygen species(ROS)and increased the ratio of glutathione/oxidized glutathione(GSH/GSSG),which in turn elevated the ubiquitination of cofilin.Consequently,the protein level of cofilin was decreased,which accounted for the inhibition of cell migration.Our study revealed GLDC as a potential tumor suppressor gene,by inhibiting the SSH1-cofilin pathway and promoting the ubiquitin dependent degradation of cofilin,affects cytoskeletal remodeling in HCC cells,prevents cell protrusion formation and ultimately inhibits the metastasis of HCC cells.Our study provides new ideas and theoretical basis for HCC anti metastasis therapy.