Identification of a Novel Human E-Cadherin Splice Variant and Assessment of Its Effects Upon EMT-Related Events.
Epithelial Cadherin (E-cadherin) is involved in calcium-dependent cell-cell adhesion and signal transduction. The E-cadherin decrease/loss is a hallmark of Epithelial to Mesenchymal Transition (EMT), a key event in tumor progression. The underlying molecular mechanisms that trigger E-cadherin loss and consequent EMT have not been completely elucidated. This study reports the identification of a novel human E-cadherin variant mRNA produced by alternative splicing. A bioinformatics evaluation of the novel mRNA sequence and biochemical verifications suggest its regulation by Nonsense-Mediated mRNA Decay (NMD). The novel E-cadherin variant was detected in 29/42 (69%) human tumor cell lines, expressed at variable levels (E-cadherin variant expression relative to the wild type mRNA = 0.05-11.6%). Stable transfection of the novel E-cadherin variant in MCF-7 cells (MCF7Ecadvar) resulted in downregulation of wild type E-cadherin expression (transcript/protein) and EMT-related changes, among them acquisition of a fibroblastic-like cell phenotype, increased expression of Twist, Snail, Zeb1, and Slug transcriptional repressors and decreased expression of ESRP1 and ESRP2 RNA binding proteins. Moreover, loss of cytokeratins and gain of vimentin, N-cadherin and Dysadherin/FXYD5 proteins was observed. Dramatic changes in cell behavior were found in MCF7Ecadvar, as judged by the decreased cell-cell adhesion (Hanging-drop assay), increased cell motility (Wound Healing) and increased cell migration (Transwell) and invasion (Transwell w/Matrigel). Some changes were found in MCF-7 cells incubated with culture medium supplemented with conditioned medium from HEK-293 cells transfected with the E-cadherin variant mRNA. Further characterization of the novel E-cadherin variant will help understanding the molecular basis of tumor progression and improve cancer diagnosis. J. Cell. Physiol. 232: 1368-1386, 2017. © 2016 Wiley Periodicals, Inc.
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
María Laura
ML
Matos
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
Lara
L
Lapyckyj
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
Marina
M
Rosso
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
María José
MJ
Besso
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
María Victoria
MV
Mencucci
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
Clara Isabel Marín
CI
Briggiler
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
Silvina
S
Giustina
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
Laura Inés
LI
Furlong
Instituto de Biología y Medicina Experimental (IBYME). National Research Council of Argentina (CONICET). Fundación IBYME, Vuelta de Obligado 2490, Buenos Aires, Argentina.
Mónica Hebe
MH
Vazquez-Levin
D000328:Adult; D017398:Alternative Splicing / Q000187:drug effects / Q000235:genetics*; D000595:Amino Acid Sequence; D015703:Antigens, CD; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004822:Epididymis / Q000187:drug effects / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D015723:Gene Library; D006801:Humans; D008297:Male; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D020871:RNA Stability / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D015703:Antigens, CD; D014408:Biomarkers, Tumor; C513384:CDH1 protein, human; D015820:Cadherins; D017077:Culture Media, Conditioned; D012333:RNA, Messenger