The Role And Underlying Mechanism Of SOCS5 In Hypoxia-Induced Hepatocellular Carcinoma Invasion And Metastasis

Objective:Hepatocellular carcinoma(HCC)is one of the most common liver malignancies,seriously endangering people’s health and life safety.Recurrence and metastasis are the biggest obstacles to curative effect.Currently,surgical resection is the main treatment method for patients with HCC,and intraoperative first portohepatic blockade is widely used because it can greatly reduce the risk of bleeding.However,it inevitably leads to ischemia and hypoxia in liver cancer,thereby promoting tumor invasion and metastasis by activating related signaling pathways.Hypoxia-inducible factor 1 alpha(HIF-1α),as a major participant in the hypoxia response of hepatocellular carcinoma,can act as a transcription factor to activate a variety of genes and participate in many aspects of tumorigenesis,including metabolism,angiogenesis,proliferation,invasion and metastasis.HIF-1α is mainly regulated by signaling molecules such as growth factors and cytokines,the most classic of which is the PI3K/Akt/m TOR pathway.In our previous study,suppressor of cytokine signaling 5(SOCS5)could activate the PI3K/Akt/m TOR signaling pathway to promote the invasion and metastasis of hepatocellular carcinoma.However,little is known about the molecular mechanisms of SOCS5 in hypoxia-related invasion and metastasis,and our study aims to fill this gap.Methods:We detected the expression of SOCS5 in 130 paraffin-embedded tissues by immunohistochemistry,and explored the role of SOCS5 in the prognosis of patients affected by hepatic portal blockade;We used the formula of Ragnum,Elvidge and Seigneuric to calculate the hypoxia score of hepatocellular carcinoma patients in TCGA to explore the relationship between SOCS5 and hypoxia;We used the c Bio Portal website and Human Protein Atlas website,and detected the protein expression of SOCS5 and HIF-1α in hepatocellular carcinoma tissues and liver cancer cell lines,and explored the relationship between SOCS5 and HIF-1α at the RNA and protein levels.Next,we explored the relationship between SOCS5 and HIF-1α at the animal level through subcutaneous tumorigenesis and lung metastases models.More importantly,we explored the relationship between SOCS5 and epithelial-mesenchymal transition in hepatocellular carcinoma through PCR,Western blotting,and immunofluorescence experiments.We constructed a hypoxic cell model using cobalt chloride,and explored the effect of SOCS5 on hypoxia-induced invasion and metastasis through Transwell and wound healing experiments.We explored the effect of SOCS5 on hypoxia-induced mitochondrial damage by detecting mitochondrial membrane potential,detecting reactive oxygen species and electron microscopy.In addition,we also performed rescue experiments using PI3 K inhibitors and m TOR inhibitors to explore the specific molecular mechanism of SOCS5 regulation of HIF-1α.Results:1.We found that the longer the hepatic hilar blocking time,the shorter the overall survival and disease-free survival of patients with high SOCS5 expression,but the length of hepatic hilar blocking time did not affect the overall survival and disease-free survival of patients with low SOCS5 expression.2.In addition,the hypoxia score of HCC patients with high SOCS5 expression was higher than that of HCC patients with low SOCS5 expression.More importantly,SOCS5 positively regulated HIF-1α protein expression in hepatocellular carcinoma in in vitro and in vivo experiments.3.We also found that SOCS5 promotes the invasion and metastasis of hepatocellular carcinoma by activating epithelial-mesenchymal transition and upregulating the expression of F-actin.More importantly,down-regulation of SOCS5 inhibited the invasion and migration of hepatocellular carcinoma by inhibiting the expression of HIF-1α.4.Interestingly,down-regulation of SOCS5 protects against hypoxia-induced mitochondrial damage by inhibiting the expression of HIF-1α.5.Finally,we also found that SOCS5 upregulates the expression of HIF-1α in hepatocellular carcinoma by activating the PI3K/m TOR/Akt pathway.Conclusion:We found that SOCS5 plays a novel role in hypoxia-induced mitochondrial damage and hypoxia-induced invasion and metastasis.Knockdown of SOCS5 can resist hypoxiainduced mitochondrial damage by inhibiting the PI3K/Akt/m TOR pathway,thereby inhibiting hypoxia-induced invasion and metastasis.More importantly,our data suggest that the development of SOCS5-specific inhibitors,an indirect inhibitor of HIF-1α,may be effective in controlling tumor micrometastases induced by blocking the first hepatic hilum during resection of hepatocellular carcinoma.