Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an inherited cancer syndrome associated with a highly aggressive form of type 2 papillary renal cell carcinoma (PRCC). Germline inactivating alterations in fumarate hydratase (FH) cause HLRCC and result in elevated levels of reactive oxygen species (ROS). Recent work indicates that FH-/- PRCC cells have increased activation of ABL1, which promotes tumor growth, but how ABL1 is activated remains unclear. Given that oxidation can regulate protein-tyrosine phosphatase (PTP) catalytic activity, inactivation of an ABL-directed PTP by ROS might account for ABL1 activation in this malignancy. Our group previously developed "q-oxPTPome", a method that globally monitors the oxidation of classical PTPs. In this study, we present a refined q-oxPTPome, increasing its sensitivity by >10X. Applying q-oxPTPome to FH-deficient cell models showed that multiple PTPs were either highly oxidized (including PTPN12) or overexpressed. Highly oxidized PTP were those with relatively high sensitivity to exogenous H2O2. Most PTP oxidation in FH-deficient cells was reversible, although nearly 40% of PTPN13 was irreversibly oxidized to the sulfonic acid state. Using substrate-trapping mutants, we mapped PTPs to their putative substrates and found that only PTPN12 could target ABL1. Furthermore, knockdown experiments identified PTPN12 as the major ABL1 phosphatase, and overexpression of PTPN12 inhibited ABL1 phosphorylation and HLRCC cell growth. These results show that ROS-induced oxidation of PTPN12 accounts for ABL1 phosphorylation in HLRCC-associated PRCC, revealing a novel mechanism for inactivating a tumor suppressor gene product and establishing a direct link between pathological PTP oxidation and neoplastic disease.
Cancer research. 2018 Oct 08 [Epub ahead of print]
Benjamin G Neel, Yang Xu, Paul Taylor, Joshua Andrade, Beatrix Ueberheide, Brian Shuch, Peter M Glazer, Ranjit S Bindra, Michael F Moran, W Marston Linehan
Department of Medicine, Perlmutter Cancer Center, New York University School of Medicine ., Medical Biophysics, University of Toronto., Hospital for Sick Children., NYU Langone Health., Biochemistry and Molecular Pharmacology, New York University., Department of Urology, Yale University School of Medicine., Department of Therapeutic Radiology, Yale University., Department of Therapeutic Radiology, Yale University School of Medicine., Cell Biology, Hospital for Sick Children., Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute.