title: RECK inhibits stemness gene expression and tumorigenicity of gastric cancer cells by suppressing ADAM-mediated Notch1 activation.
abstract: The Reversion-inducing Cysteine-rich Protein with Kazal Motifs (RECK) gene encodes a membrane-anchored glycoprotein that exhibits strong inhibitory activity against various matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase 10 (ADAM10). RECK functions as a tumor suppressor by inhibiting migration, invasion, and angiogenesis. However, whether RECK can modulate the stem-like phenotypes of cancer cells is not known. In this study, we demonstrate that RECK is down-regulated in gastric cancer cells and is further reduced in CD133-positive cancer stem-like cells. Ectopic expression of RECK induces down-regulation of the expression of stemness genes including Sox2, Oct4, and Nanog and the cancer stem cell marker CD133. Treatment of DAPT (a γ-secretase inhibitor) or TAPI-2 (a hydroxamate-based inhibitor of MMPs, tumor necrosis factor α converting enzyme and ADAM17) reduces Notch1 shedding and activation which results in attenuation of stemness genes and CD133. Our data show that ADAM10 and ADAM17 are co-pulled down by RECK suggesting a physical interaction between RECK and ADAMs on cell surface. In addition, RECK suppresses sphere formation and sphere size of CD133-positive gastric cancer cells. Overexpression of Notch intracellular domain (NICD) or ADAM17 effectively reverse the inhibitory effect of RECK in CD133-positive cells. More importantly, RECK reduces tumorigenic activity of CD133-positive cells in vivo. Conversely, knockdown of RECK in non-tumorigenic GI2 cells increases stemness and CD133 expression and sphere forming ability. Collectively, these results indicate that RECK represses stemness gene expression and stem-like properties by inhibiting ADAM-mediated Notch1 shedding and activation.
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China.
authors.forename: Kun-Jing
authors.initials: KJ
authors.lastname: Hong
authors.forename: Deng-Chyang
authors.initials: DC
authors.lastname: Wu
authors.forename: Kuang-Hung
authors.initials: KH
authors.lastname: Cheng
authors.forename: Li-Tzong
authors.initials: LT
authors.lastname: Chen
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Hung
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D058851:GPI-Linked Proteins / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013274:Stomach Neoplasms
chemical_list: D058851:GPI-Linked Proteins; C497761:NOTCH1 protein, human; C115460:RECK protein, human; D012333:RNA, Messenger; D051881:Receptor, Notch1; D051722:ADAM Proteins