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Présentation Poster; International audience; Estrogen receptor alpha 36 (ERα36) is a variant of the canonical estrogen receptor alpha (ERα66), whose high expression level correlates with a poor survival prognosis for breast cancer patients. While our previous results indicated that a high ERα36 expression level correlates with hormone independent growth and enhanced metastatic potential (Chamard-Jovenin et al, 2015; doi: 10.1186/s12918-015-0178-7) the mechanisms of ERα36 expression onset and the consequences for the normal mammary gland are poorly documented. Therefore, we explored (i) the methylation status of ERα36 promoter in 60 mammary tumor samples and (ii) the consequences of a ERα36 overexpression in vitro in MCF-10A normal mammary epithelial cells and in vivo in a unique model of MMTV-ERα36 transgenic mouse strain wherein the human ERα36 mRNA was specifically expressed in the mammary gland. Our data indicate a marked correlation between promoter methylation and ERα36 expression. Concomitantly, ERα36 overexpression lowered proliferation rate but enhanced migration and survival of the MCF-10A cell line. By a combination of bioinformatics and computational analyses of microarray data, we identified hierarchical gene networks, downstream of ERα36. In vivo, human ERα36 expression led to duct epithelium thinning and E-cadherin expression loss in adult but not prepubescent mice. Here, we show that ERα36 expression could be driven, at least in part, by epigenetic mechanisms. Moreover, an enhanced expression of ERα36 is sufficient, by itself, to disrupt normal breast epithelial phenotype in vivo and in vitro through a dominant-positive effect on nongenomic estrogen signaling pathways. These results also suggest that, in the presence of endogenous estradiol, ERα36 overexpression in vivo contributes to alter mammary gland architecture which may support pre-neoplastic lesion and augment breast cancer risk.

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published in Journal of Clinical Oncology, vol. 30, 2012, abstract 103; International audience; Background: Colorectal cancer (CRC) is the 2nd most common cancer with more than one million new cases diagnosed every year. From 2006 to 2008, several studies showed the importance of the KRAS oncogene in the treatment of metastatic CRC (mCRC) and response to anti-EGFR therapies like cetuximab or panitumumab. KRAS is a small G protein which can bear activating mutations in 40% cases of mCRC. Numerous methods have been described for the detection of KRAS mutations in FFPE tissues. Direct sequencing is the gold standard but the most sensitive methods are real time PCR assays based. The new COBAS4800 KRAS developed by Roche Diagnostics is a CE IVD validated assay using real time PCR and TaqMelt technology. This assay is validated for the detection of 19 KRAS somatic mutations on exon 2 (codons 12/13) and exon 3 (codon 61) in specimen containing at least 5% of mutated tumoral cells. Methods: We compared COBAS with previously validated PCR TaqMan and PCR High Resolution Melting (HRM) assays. The PCR TaqMan and HRM are a real time PCR based assays. TaqMan can detect accurately 0.5 to 1% of mutated tumoral DNA on codon 12 (G12A, G12C, G12D, G12R, G12S and G12V) and on codon 13 (G13D). HRM can detect 5 to 10% of tumoral DNA on codon 12 and 13. 80 FFPE samples of colorectal tumors resections or biopsies have been collected and processed with the 3 assays. Results have been compared using kappa statistics. Results: On 80 samples, 69 were interpretable with COBAS and TaqMan and 62 with COBAS and HRM. No statistically significant difference between COBAS and TaqMan was found (k=0.942 ; p

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National audience

published in Oncologie 13(9)S4; National audience

International audience; Our work aimed to identify the ability of the HNSCC cell line Cal 27 to induce angiogenesis, regarding PTEN expression and anti-EGFR treatment. Cal 27, a human HNSCC cell line expressing PTEN has been transfected by a PTEN-siRNA and exposed to cetuximab for 48 hours. The culture media were then collected to be used as conditionned media for HUVEC and aortic rings culture. Aortic rings sprouting and tubular structures from HUVEC have been investigated by microscopy and quantified by AngioQuant software. The conditioned media have been also characterized by an analysis of key factors involved in angiogenesis regulation using Proteome Profiler Array. The anti-angiogenic effect of cetuximab in HNSCC seems to result from a direct effect of the anti-EGFR on endothelial cells rather than an effect mediated by tumoral cells, despite a VEGF concentration significantly lower due to cetuximab exposure. PTEN is involved in the regulation of vasculature in HNSCC. But surprisingly, loss of PTEN expression in Cal 27 leads to a reduction of the tumoral cells ability to induce angiogenesis. This process is not linked to the VEGF concentration changes but is mediated by a global change in the molecular constitution of conditioned media.