Differential regulation of TROP2 release by PKC isoforms through vesicles and ADAM17

TY - JOUR

T1 - Differential regulation of TROP2 release by PKC isoforms through vesicles and ADAM17

AU - Wanger, Tim M

AU - Dewitt, Sharon

AU - Collins, Anne

AU - Maitland, Norman J

AU - Poghosyan, Zaruhi

AU - Knäuper, Vera

N1 - Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

PY - 2015/7

Y1 - 2015/7

N2 - 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.

AB - 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.

U2 - 10.1016/j.cellsig.2015.03.017

DO - 10.1016/j.cellsig.2015.03.017

M3 - Article

C2 - 25817572

SN - 0898-6568

VL - 27

SP - 1325

EP - 1335

JO - Cellular Signalling

JF - Cellular Signalling

IS - 7

ER -