The Role Of Ubiquitin-Specific Peptidase 46 In The Development Of Human Esophageal Squamous Cell Carcinoma

Background: Esophageal squamous cell carcinoma(ESCC)is one of the most important subtypes of esophageal cancer.China is a high-risk area for ESCC.However,the major risk factors and molecular mechanism of ESCC remain unknown.Ubiquitination is a common and essential posttranslational modification,and involves in multiple biological processes including tumorigenesis and development.Ubiquitinspecific peptidase 46(USP46)belongs to the USP family of DUBs,and plays vital roles in various tumors.However,the functional role of USP46 in ESCC remains unclear.Methods: 48 paired ESCC samples were used for immunohistochemistry(IHC)staining to determine that USP46 was up-regulated in ESCC.The effects of USP46 on the proliferation,migration and invasion of ESCC cell lines were verified using cell proliferation assay,colony formation assay,cell migration and invasion assays and wound-healing assay.The function of USP46 on tumor growth and metastasis in vivo was examined using xenograft and tail-vein injection lung metastasis mouse models.Co-immunoprecipitation assay and mass spectrometry were used to find out ENO1 as a potential substrate of USP46.The regulation of USP46 on ENO1 stability was determined by cycloheximide pulse-chase assay and ubiquitination assay.The correlation between USP46 and ENO1 expression in clinical ESCC samples was confirmed by IHC analysis.Results: In this study,we found that USP46 is overexpressed in clinical ESCC samples,especially in patients with positive lymph node metastasis.Even though USP46 has no significant effect on tumor proliferation,we revealed that it could enhance the migration and invasion of ESCC cells by mediating the EMT process,and promote lung metastasis of ESCC in vivo.Besides,we illustrated that USP46 is a bona fide deubiquitinating enzyme to stabilize the protein level of ENO1 through deubiquitination.The USP46 and ENO1 protein levels were overexpressed uniformly in the ESCC samples.Conclusions: USP46 significantly promotes ESCC metastasis both in vitro and in vivo,providing us a potential therapeutic target for the treatment of ESCC.