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Oncology reports

Argininosuccinate lyase interacts with cyclin A2 in cytoplasm and modulates growth of liver tumor cells.


PMID 28035420

Abstract

Arginine is a critical amino acid in specific cancer types including hepatocellular carcinoma (HCC) and melanoma. Novel molecular mechanisms and therapeutic targets in arginine metabolism-mediated cancer formation await further identification. Our laboratory has previously demonstrated that arginine metabolic enzyme argininosuccinate lyase (ASL) promoted HCC formation in part via maintenance of cyclinxa0A2 protein expression and arginine production for channeling to nitric oxide synthase. In this study, we investigated the mechanism by which ASL regulates cyclinxa0A2 expression. We found that ASL interacted with cyclinxa0A2 in HCC cells and the localization of their interaction was in the cytoplasm. Mutation of essential residues for enzymatic activity of ASL did not affect the binding of ASL to cyclinxa0A2. Moreover, the mutant ASL retained the ability to restore the decreased tumorigenicity caused by ASL shRNA. Furthermore, overexpression of ASL conferred resistance to arginine deprivation therapy. Finally, the important pathways and potential therapeutic targets in ASL-regulated HCC were identified by bioinformatics analyses with Metacore database and Connectivity Map database. Our analyses suggested that bisoprolol, celecoxib, and ipratropium bromide, are potential therapeutics for ASL-regulated HCC formation. Thus, ASL interacts with cyclinxa0A2 in cytoplasm, and may promote HCC formation through this non-enzymatic function. Overexpression of ASL may be a contributing factor in drug resistance for arginine deprivation therapy.