Deubiquitination of DNM1L by USP3 triggers the development and metastasis of gallbladder carcinoma.

Background: Patients diagnosed with gallbladder carcinoma (GBC) accompanied by hepatic metastasis exhibit unfavorable prognoses generally. Mitochondrial dysfunction promotes cellular transformation and cancer cell survival implicating its importance in cancer development. Previous studies have indicated that dynamin 1 like (DNM1L) is a key mediator of mitochondrial fission. However, whether DNM1L regulates mitochondrial homeostasis in GBC remains unknown.

Methods: The morphological changes of mitochondria were investigated by transmission electron microscopy and mitoTracker red staining. Co-immunoprecipitation assay was performed to detect the interaction of ubiquitin-specific protease-3 (USP3) and DNM1L. The cell-derived xenograft and liver metastasis tumor models were established to validate the function of DNM1L in vivo. The metabolomics data from transcriptomics/metabolomics were analyzed to identify the differentially expressed genes/metabolites of DNM1L in GBC.

Results: DNM1L exhibited a marked upregulation in clinical GBC tissues compared to the adjacent tissues, and it promoted proliferation, invasiveness, and migration capability of GBC cells by inducing mitochondrial dysfunction. Mice subcutaneously injected with DNM1L overexpression cells exhibited elevated intrahepatic metastatic nodules within their livers. USP3, a deubiquitinating enzyme, was demonstrated to directly interact with DNM1L and it specifically cleaved the K48-linked polyubiquitin chains to deubiquitinate and stabilize DNM1L. By integrating two omics, we found several altered pathways and speculated that DNM1L disturbed DNA synthesis and glycine, serine, threonine, and pyrimidine metabolism pathways.

Conclusion: Our findings suggest that DNM1L is a promising clinical target for GBC treatment and that focusing on DNM1L may provide new insights into GBC strategy.