USP22 Promotes Osteosarcoma Growth By Regulating HK2 Expression

Background and Objective:Osteosarcoma is a primary malignant tumor of bone,ranking second in the incidence of primary bone tumors,next to plasma cell myeloma.Osteosarcoma can metastasize early,so it has a high degree of malignancy,a poor prognosis,and tends to occur in adolescents.The cure rate of surgery alone is only 15%-20%.Therefore,the search for effective molecular targets for the treatment of osteosarcoma has very important clinical significance.USP22 plays an important role in the development and progression of various malignant tumors.It has the biological activity of covalently binding substrate proteins,regulating protein degradation,and regulating cell invasion,migration,proliferation and apoptosis.However,the specific molecular mechanism of USP22 affecting the growth of osteosarcoma is still not very clear.The glycolysis level increases during the development of malignant tumors.As one of the major rate-limiting enzymes of glycolysis pathway,HK2 has been confirmed to play a decisive role in the progression of malignant tumors by numerous studies.However,the molecular mechanism of HK2 in osteosarcoma is rarely found.The purpose of this paper is to find a new molecular mechanism affecting the growth of osteosarcoma about USP22 and HK2.Method:1.Quantitative PCR and Western blot results confirmed that USP22 levels in osteosarcoma tissues and cells were significantly higher than those in paranocarcinoma tissues and normal osteoblasts.2.PCR and western blot method of choosing the best sh USP22 plasmid and transfection of osteosarcoma cells,observe the change of cell growth ability using CCK8,Ed U,plate cloning experiments.The proportion of apoptosis was detected by flow cytometry.Finally,the effect of sh USP22 on the growth of osteosarcoma cells in vivo was examined by subcutaneous tumor formation model in nude mice.3.USP22 expression change in osteosarcoma cells,PCR and western blot method to analysis the expression of HK2.The expression of HK2 in cancer and corresponding adjacent tissues was detected,and the correlation between HK2 and USP22 expression in cancer tissues was analyzed.Then,HK2 expression was up-regulated by sh USP22 in osteosarcoma cells,and the growth of tumor cells was observed by CCK8 and Ed U.Finally,HK2 expression was up-regulated in cells with stable low USP22 expression.G6 P assay,glucose consumption assay,lactic acid generation assay and ATP generation assay were used to observe the glycolysis of tumor cells.Results:1.The expression level of USP22 in osteosarcoma tissues and cells was significantly increased by quantitative PCR and western blotting(p<0.01).2.USP22 expression was knocked down in osteosarcoma cells,and the proliferation of osteosarcoma cells was reduced in vitro(p < 0.01);Increased apoptosis(p<0.05);Tumorigenic experiments confirmed that osteosarcoma growth was inhibited in vivo after USP22 knockdown(p<0.05).3.In osteosarcoma cells,HK2 expression is elevated and upregulated USP22 expression is increased relative to HK2 expression.What else,We found that the growth inhibition of osteosarcoma caused by decreased glycolysis level caused by down-regulation of USP22 expression was reversed by up-regulation of HK2.Conclusion:USP22 regulates HK2 expression to promote glycolysis of osteosarcoma and thus promote the growth of osteosarcoma.