Wnt pathway reprogramming during human embryonal carcinoma differentiation and potential for therapeutic targetingReport as inadecuate




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BMC Cancer

, 9:383

First Online: 29 October 2009Received: 17 March 2009Accepted: 29 October 2009DOI: 10.1186-1471-2407-9-383

Cite this article as: Snow, G.E., Kasper, A.C., Busch, A.M. et al. BMC Cancer 2009 9: 383. doi:10.1186-1471-2407-9-383

Abstract

BackgroundTesticular germ cell tumors TGCTs are classified as seminonas or non-seminomas of which a major subset is embryonal carcinoma EC that can differentiate into diverse tissues. The pluripotent nature of human ECs resembles that of embryonic stem ES cells. Many Wnt signalling species are regulated during differentiation of TGCT-derived EC cells. This study comprehensively investigated expression profiles of Wnt signalling components regulated during induced differentiation of EC cells and explored the role of key components in maintaining pluripotency.

MethodsHuman embryonal carcinoma cells were stably infected with a lentiviral construct carrying a canonical Wnt responsive reporter to assess Wnt signalling activity following induced differentiation. Cells were differentiated with all-trans retinoic acid RA or by targeted repression of pluripotency factor, POU5F1. A Wnt pathway real-time-PCR array was used to evaluate changes in gene expression as cells differentiated. Highlighted Wnt pathway genes were then specifically repressed using siRNA or stable shRNA and transfected EC cells were assessed for proliferation, differentiation status and levels of core pluripotency genes.

ResultsCanonical Wnt signalling activity was low basally in undifferentiated EC cells, but substantially increased with induced differentiation. Wnt pathway gene expression levels were compared during induced differentiation and many components were altered including ligands WNT2B, receptors FZD5, FZD6, FZD10, secreted inhibitors SFRP4, SFRP1, and other effectors of Wnt signalling FRAT2, DAAM1, PITX2, Porcupine. Independent repression of FZD5, FZD7 and WNT5A using transient as well as stable methods of RNA interference RNAi inhibited cell growth of pluripotent NT2-D1 human EC cells, but did not appreciably induce differentiation or repress key pluripotency genes. Silencing of FZD7 gave the greatest growth suppression in all human EC cell lines tested including NT2-D1, NT2-D1-R1, Tera-1 and 833K cells.

ConclusionDuring induced differentiation of human EC cells, the Wnt signalling pathway is reprogrammed and canonical Wnt signalling induced. Specific species regulating non-canonical Wnt signalling conferred growth inhibition when targeted for repression in these EC cells. Notably, FZD7 repression significantly inhibited growth of human EC cells and is a promising therapeutic target for TGCTs.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2407-9-383 contains supplementary material, which is available to authorized users.

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Author: Grace E Snow - Allison C Kasper - Alexander M Busch - Elisabeth Schwarz - Katherine E Ewings - Thomas Bee - Michael J 

Source: https://link.springer.com/







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