title: Differential regulation of TROP2 release by PKC isoforms through vesicles and ADAM17.
abstract: TROP2, a cancer cell surface protein with both pro-oncogenic and anti-oncogenic properties is cleaved by ADAM17. ADAM17 dependent cleavage requires novel PKC activity which is blocked by the ADAM10/ADAM17 inhibitor GW64 as well as by the PKC inhibitor Bim-1. Full length TROP2 release is induced by classical PKC activation and blocked by Gö6979, without affecting ADAM17 dependent TROP2 cleavage. Full length TROP2 is released in ectosomes, as inhibition of endocytosis did not prevent release. Inhibition of the atypical PKC isoform PKCζ stimulated metalloproteinase dependent N-terminal alternative TROP2 cleavage. The resulting alternative TROP2 cleavage product remains membrane associated via a disulphide bond, but is released in microvesicles with an average size of 107nm. Inhibition of endocytosis following PKCζ inhibition prevented alternative cleavage and release of TROP2, suggesting that these events require endocytic uptake and exosomal release of the corresponding microvesicles. The alternative TROP2 cleavage product was also found in PC3 cell lysates following deglycosylation, and may represent a novel biomarker in prostate cancer.
authors: College of Biomedical and Life Sciences, Cardiff University, Dental School, Cardiff CF14 4XY, United Kingdom.
authors: Tim M
authors: TM
authors: Wanger
authors: College of Biomedical and Life Sciences, Cardiff University, Dental School, Cardiff CF14 4XY, United Kingdom.
authors: Sharon
authors: S
authors: Dewitt
authors: YCR Cancer Research Unit, Department of Biology, University of York, York YO10 5DD, United Kingdom.
authors: Anne
authors: A
authors: Collins
authors: YCR Cancer Research Unit, Department of Biology, University of York, York YO10 5DD, United Kingdom.
authors: Norman J
authors: NJ
authors: Maitland
authors: College of Biomedical and Life Sciences, Cardiff University, Medical School, Cardiff CF14 4XN, United Kingdom.
authors: Zaruhi
authors: Z
authors: Poghosyan
authors: College of Biomedical and Life Sciences, Cardiff University, Dental School, Cardiff CF14 4XY, United Kingdom.
authors: Vera
authors: V
authors: Knäuper
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072198:ADAM17 Protein; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000099221:Protein Kinase C zeta
chemical_list: D051722:ADAM Proteins; D000072198:ADAM17 Protein; D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D011493:Protein Kinase C; D034741:RNA, Small Interfering; D013755:Tetradecanoylphorbol Acetate; D000099221:Protein Kinase C zeta; C499380:TACSTD2 protein, human; C000606462:ADAM17 protein, human
keywords: ADAM17; Ectodomain shedding; Microvesicles; PKC; TROP2