Concanavalin-A-induced autophagy biomarkers requires membrane type-1 matrix metalloproteinase intracellular signaling in glioblastoma cells.
Pre-clinical trials for cancer therapeutics support the anti-neoplastic properties of the lectin from Canavalia ensiformis (Concanavalin-A, ConA) in targeting apoptosis and autophagy in a variety of cancer cells. Given that membrane type-1 matrix metalloproteinase (MT1-MMP), a plasma membrane-anchored matrix metalloproteinase, is a glycoprotein strongly expressed in radioresistant and chemoresistant glioblastoma that mediates pro-apoptotic signalling in brain cancer cells, we investigated whether MT1-MMP could also signal autophagy. Among the four lectins tested, we found that the mannopyranoside/glucopyranoside-binding ConA, which is also well documented to trigger MT1-MMP expression, increases autophagic acidic vacuoles formation as demonstrated by Acridine Orange cell staining. Although siRNA-mediated MT1-MMP gene silencing effectively reversed ConA-induced autophagy, inhibition of the MT1-MMP extracellular catalytic function with Actinonin or Ilomastat did not. Conversely, direct overexpression of the recombinant Wt-MT1-MMP protein triggered proMMP-2 activation and green fluorescent protein-microtubule-associated protein light chain 3 puncta indicative of autophagosomes formation, while deletion of MT1-MMP's cytoplasmic domain disabled such autophagy induction. ConA-treated U87 cells also showed an upregulation of BNIP3 and of autophagy-related gene members autophagy-related protein 3, autophagy-related protein 12 and autophagy-related protein 16-like 1, where respective inductions were reversed when MT1-MMP gene expression was silenced. Altogether, we provide molecular evidence supporting the pro-autophagic mechanism of action of ConA in glioblastoma cells. We also highlight new signal transduction functions of MT1-MMP within apoptotic and autophagic pathways that often characterize cancer cell responses to chemotherapeutic drugs.
Laboratoire d'Oncologie Moléculaire,  Centre de Recherche BioMED, Québec,  Canada.
Jonathan
J
Pratt
René
R
Roy
Borhane
B
Annabi
D000165:Acridine Orange; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D001932:Brain Neoplasms / Q000188:drug therapy / Q000473:pathology*; D045744:Cell Line, Tumor; D003208:Concanavalin A / Q000494:pharmacology*; D005456:Fluorescent Dyes; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D020868:Gene Silencing; D005909:Glioblastoma / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008358:Mannose / Q000737:chemistry / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism
D005456:Fluorescent Dyes; D006877:Hydroxamic Acids; D007211:Indoles; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D003208:Concanavalin A; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14; D000165:Acridine Orange; C119203:ilomastat; C010531:actinonin; D008358:Mannose