Laminin-5 with transforming growth factor-beta1 induces epithelial to mesenchymal transition in hepatocellular carcinoma.
OBJECTIVE
How hepatocellular carcinoma (HCC) cells acquire the ability to invade surrounding tissue is unknown, but epithelial mesenchymal transition (EMT) likely plays a role. We investigate how transforming growth factor (TGF)-beta1 and extracellular matrix protein Laminin-5 (Ln-5) induce EMT and cancer invasion.


METHODS
Snail, Slug, E-cadherin, beta-catenin and Ln-5 were investigated on HCC tissues and on HCC cell lines.


RESULTS
We show that in HCC but not in peritumoral tissue of the same HCC patients, Ln-5, Snail, and Slug are up-regulated, E-cadherin is down-regulated and beta-catenin is translocated into the nuclei. In vitro, HCC "invasive" cells, partially EMT-transformed, show low levels of E-cadherin. In presence of Ln-5, Snail, and Slug are up-regulated, E-cadherin is down-regulated, beta-catenin is translocated into the nuclei, and cells undergo a dramatic morphological change, becoming scattered and undergoing a complete EMT. This effect is reversed by anti-alpha3 but not by anti-alpha6 integrin blocking antibody. HCC "noninvasive" cells are not EMT-transformed, and have constitutively high levels of E-cadherin. In presence of Ln-5, cells undergo partial EMT, Snail, and Slug are up-regulated, E-cadherin is down-regulated but cells do not scatter. However, the presence of both Ln-5 and TGF-beta1 completes the EMT process, beta-catenin is translocated into the nuclei, cells scatter and become invasive, recalling the "invasive" cells. In this case, too, the effect is reversed by anti-alpha3 integrin blocking antibody.


CONCLUSIONS
Our study shows that Ln-5 and TGF-beta1 cooperatively induce EMT in HCC, suggesting the microenvironment as a potential target for new biological therapies.
Giannelli
G
G
Department of Internal Medicine, Immunology, and Infectious Diseases, Section of Internal Medicine, University of Bari Medical School, Bari, Italy. g.giannelli@intmed.uniba.it
Bergamini
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C
Fransvea
E
E
Sgarra
C
C
Antonaci
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S
D015820:Cadherins / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000503:physiopathology* / Q000556:secondary; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000473:pathology* / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008648:Mesoderm / Q000473:pathology*; D009361:Neoplasm Invasiveness; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D053773:Transforming Growth Factor beta1; D051176:beta Catenin / Q000235:genetics; D000097794:Kalinin
D015820:Cadherins; D015815:Cell Adhesion Molecules; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D051176:beta Catenin; D000097794:Kalinin; C000604407:SNAI1 protein, human; C508960:TGFB1 protein, human