Let-7 microRNA and HMGA2 levels of expression are not inversely linked in adipocytic tumors: analysis of 56 lipomas and liposarcomas with molecular cytogenetic data.
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| Abstract |
The aim of our study was first to assess the role of HMGA2 expression in the pathogenesis of adipocytic tumors (AT) and, second, to seek a potential correlation between overexpression of HMGA2 and let-7 expression inhibition by analyzing a series of 56 benign and malignant AT with molecular cytogenetic data. We measured the levels of expression of HMGA2 mRNA and of eight members of the let-7 microRNA family using quantitative RT-PCR and expression of HMGA2 protein using immunohistochemistry. HMGA2 was highly overexpressed in 100% of well-differentiated/dedifferentiated liposarcomas (WDLPS/DDLPS), all with HMGA2 amplification, and 100% of lipomas with HMGA2 rearrangement. Overexpression of HMGA2 mRNA was detected in 76% of lipomas without HMGA2 rearrangement. HMGA2 protein expression was detected in 100% of lipomas with HMGA2 rearrangement and 48% of lipomas without HMGA2 rearrangement. We detected decreased expression levels of some let-7 members in a significant proportion of AT. Notably, let-7b and let-7g were inhibited in 61% of WDLPS/DDLPS. In lipomas, each type of let-7 was inhibited in approximately one-third of the cases. Although overexpression of both HMGA2 mRNA and protein in a majority of ordinary lipomas without HMGA2 structural rearrangement may have suggested a potential role for let-7 microRNAs, we did not observe a significant link with let-7 inhibition in such cases. Our results indicate that inhibition of let-7 microRNA expression may participate in the deregulation of HMGA2 in AT but that this inhibition is neither a prominent stimulator for HMGA2 overexpression nor a surrogate to genomic HMGA2 rearrangements.
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| Authors | Laurence Bianchini, Esma Saâda, Elisabet Gjernes, Marion Marty, Juliette Haudebourg, Isabelle Birtwisle-Peyrottes, Frédérique Keslair, Bérangère Chignon-Sicard, Emmanuel Chamorey, Florence Pedeutour |
| Journal | Genes, chromosomes & cancer (Genes Chromosomes Cancer) Vol. 50 Issue 6 Pg. 442-55 (Jun 2011) ISSN: 1098-2264 [Electronic] United States |
| PMID | 21412931 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
| Copyright | Copyright © 2011 Wiley-Liss, Inc. |
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