PRL-3 promotes epithelial mesenchymal transition by regulating cadherin directly.
PRL-3 is a key gene associated with progression and metastasis of colorectal cancer. Recently PRL-3 was suggested to promote epithelial mesenchymal transition (EMT) by downregulating E-cadherin expression. But the mechanisms of EMT induced by PRL-3 remain largely unknown. Here we found that PRL-3 could also promote EMT in a colorectal cancer cell model SW480 with deficient E-cadherin expression in vivo and in vitro. PRL-3 stable overexpression or knockdown SW480 cells were injected subcutaneously into nude mice. Immunohistochemical analyses of tumor samples from nude mice showed that PRL-3 promoted upregulation of mesenchymal marker vimentin and downregulation of epithelial markers E-cadherin and cytokeratin. Glycogen synthase kinase-3beta inactivated by PRL-3 as assessed by phosphospecific antibodies was a key event in EMT induced by PRL-3. Inhibition of glycogen synthase kinase-3beta by lithium chloride, a highly selective inhibitor, leading to phosphorylation of glycogen synthase kinase-3beta increased Snail expression. In order to identify the direct effects of PRL-3, we isolated CDH22, one member of cadherin family, as a new candidate of interacting proteins of PRL-3 in yeast two-hybrid systems, and the interaction was confirmed in vitro by GST pull-down assay or in exogenous cell systems and endogenous colorectal cancer cells by co-immunoprecipitation assay and co-localization analysis. We observed that PRL-3 promoted downregulation of CDH22 expression. Interestingly, expression of E-cadherin was recovered in SW480 cells after PRL-3 was knocked-down. Our results first linked PRL-3 to cadherin directly. It provided new insights into the regulatory mechanisms of EMT induced by PRL-3.
Liu
Yuhong
Y
Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China. dyq@fimmu.com
Zhou
Jun
J
Chen
Juanzhi
J
Gao
Weizhe
W
Le
Yi
Y
Ding
Yanqing
Y
Li
Jianming
J
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D015820:Cadherins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology; D045744:Cell Line, Tumor / Q000378:metabolism / Q000637:transplantation; D054338:Cell Transdifferentiation / Q000502:physiology*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D055785:Gene Knockdown Techniques; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000502:physiology; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D018021:Lithium Chloride / Q000494:pharmacology; D008648:Mesoderm / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D025941:Protein Interaction Mapping; D017027:Protein Tyrosine Phosphatases / Q000502:physiology*; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics
D015820:Cadherins; D009363:Neoplasm Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; C099417:CDH22 protein, human; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3; C484730:PTP4A3 protein, human; D017027:Protein Tyrosine Phosphatases; D018021:Lithium Chloride