title: Phorbol ester-induced shedding of the prostate cancer marker transmembrane protein with epidermal growth factor and two follistatin motifs 2 is mediated by the disintegrin and metalloproteinase-17.
abstract: The transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2) is expressed in prostate and brain and shed from the cell surface in a metalloproteinase-dependent fashion. Neither the sheddase(s) responsible for TMEFF2 shedding nor the physiological significance or activity of the soluble TMEFF2 ectodomain (TMEFF2-ECD) has been identified. In the present study we present new evidence that a disintegrin and metalloproteinase-17 (ADAM17) is responsible for phorbol 12-myristate 13-acetate-induced release of TMEFF2-ECD using small interfering RNA to ablate ADAM17 expression or by inhibiting enzymatic activity. A single well shedding assay monitoring the release of alkaline phosphatase-tagged TMEFF2-ECD into medium and the generation of 22- and 14-kDa C-terminal fragments in lysates were dependent on ADAM17 activity. A gamma-secretase inhibitor prevented the formation of a 10-kDa fragment in cell lysates, thus establishing TMEFF2 as a novel substrate for regulated intramembrane proteolysis. We assigned proliferation-inducing activity to TMEFF2. Inhibition of TMEFF2 shedding using synthetic metalloproteinase inhibitors or small interfering RNA targeting TMEFF2 expression yielded a statistically significant reduction of cell proliferation in the lymph node-derived prostate cancer cells (LNCaPs) and a human embryonic kidney (HEK293) cell line overexpressing TMEFF2. The TMEFF2-ECD was able to induce ERK1/2 phosphorylation in an epidermal growth factor receptor (or ErbB1)-dependent manner in HEK293 cells. Our data suggest that TMEFF2 contributes to cell proliferation in an ADAM17-dependent autocrine fashion in cells expressing this protein.
authors.affiliation: Metalloproteinase Research Group, Department of Biology, University of York, Heslington, York, UK.
authors.forename: Nazim
authors.initials: N
authors.lastname: Ali
authors.forename: Vera
authors.initials: V
authors.lastname: Knaüper
mesh_terms: D051722:ADAM Proteins / Q000737:chemistry*; D000072198:ADAM17 Protein; D020816:Amino Acid Motifs; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D049109:Cell Proliferation; D004815:Epidermal Growth Factor / Q000378:metabolism*; D038681:Follistatin / Q000737:chemistry*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D009363:Neoplasm Proteins / Q000378:metabolism*; D010703:Phorbol Esters / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000378:metabolism*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D038681:Follistatin; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D010703:Phorbol Esters; D034741:RNA, Small Interfering; C423567:TMEFF2 protein, human; D004815:Epidermal Growth Factor; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human