Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6096874 | Gastroenterology | 2008 | 13 Pages |
Abstract
Background & Aims: The finding of bone morphogenetic protein (BMP) receptor 1a mutations in juvenile polyposis suggests that BMPs are important in colorectal cancer (CRC). We investigated the BMP pathway in sporadic CRC. Methods: We investigated BMP receptor (BMPR) expression using immunoblotting and sequenced BMPR2 in CRC cell lines. We assessed the expression of BMPRs, SMAD4, and pSMAD1/5/8 in 72 sporadic CRCs using a tissue microarray and immunohistochemistry. We assessed the effect of reintroduction of wild-type BMPR2 on BMP pathway activity and the effect of wild-type or mutated BMPR2 3â² untranslated region (UTR) sequences on protein expression by attachment to pCMV-Luc. Results: BMPR2 and SMAD4 protein expression is abrogated in microsatellite unstable (MSI) and microsatellite stable (MSS) cell lines, respectively. BMPR2 3â²UTR is mutated in all MSI and in none of the MSS cell lines. Mutant BMPR2 3â²UTR sequences reduced luciferase expression 10-fold compared with wild-type BMPR2 3â²UTR. BMPR2 expression is impaired more frequently in MSI CRCs than MSS (85% vs 29%; P < .0001) and shows a mutually exclusive pattern of impaired expression compared with SMAD4. Nine of 11 MSI cancers with impaired expression of BMPR2 have microsatellite mutations. The BMP pathway is inactivated, as judged by nuclear pSMAD1/5/8 expression, in 70% of CRCs, and this correlates with BMPR and SMAD4 loss. Conclusions: Our data suggest that the BMP pathway is inactivated in the majority of sporadic CRCs. In MSI CRC this is associated predominantly with impaired BMPR2 expression and in MSS CRC with impaired SMAD4 expression.
Keywords
MSITGFBMPRMSSGFPTMAMMRACVR2transforming growth factormismatch repairmicrosatellite stableColorectal cancerCMVcytomegalovirusBMPUTR یا untranslated regions untranslated regionTissue microarraypolymerase chain reactionPCRgreen fluorescent proteinBone morphogenetic proteinCRCbone morphogenetic protein receptor
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Authors
Liudmila L. Kodach, Eliza Wiercinska, Noel F.C.C. de Miranda, Sylvia A. Bleuming, Alex R. Musler, Maikel P. Peppelenbosch, Evelien Dekker, Gijs R. van den Brink, Carel J.M. van Noesel, Hans Morreau, Daniel W. Hommes, Peter ten Dijke,