Project description:Subtle variations in Pten dose determine cancer susceptibility: Gene expression profiling for MEF cells from a Ptenhy/+ mouse model. We have analyzed the survival and tumor spectrum in a population of Pten âhypermorphicâ mice (Ptenhy/+), which express approximately 80% of total Pten protein. Notably, the Ptenhy/+ developed a spectrum of tumors of variable latencies, with breast tumors occurring at the highest penetrance. Surprisingly, all breast tumors analyzed retain two intact copies of Pten, and maintain Pten protein levels above that observed in heterozygosity. Importantly, subtle down-regulation of Pten was found to alter the expression profile of genes involved in cell proliferation. Taken together, our findings support the notion that initiation of tumorigenesis can occur in the absence of genetic hits, thereby questioning the uniqueness of a saltatory model for cancer susceptibility. In order to understand whether subtle variations in Pten level may affect pathways involved in tumorigenesis, we analyzed the genome-wide expression profile of Ptenhy/+ mouse embryonic fibroblasts (MEFs). In the Ptenhy/+ mouse model, mice are born with approximately 80% of total Pten protein and are viable and normally fertile. To decrease the expression level of Pten below homozygosity, we targeted intron 3 of Pten with a neomycin (Neo) cassette, under the control of the strong CMV promoter, thereby taking advantage of transcriptional interference. Next, we intercrossed Pten hy/+ mice with Pten+/- mice to generate cohorts of hypomorphic littermate mice with decreasing levels of Pten expression as follows: Ptenwt > Ptenhy/+ > Pten+/- >Ptenhy/- mice littermates. To preserve a constant 129/C57BL/6 mixed genetic background, we have crossed Pten hy/+ mice with Pten +/- for more than seven generations prior to analysis. As expected, Ptenhy/+ mouse embryonic fibroblasts (MEFs) display a level of Pten protein below Ptenwt and above Pten+/- .
Project description:Subtle variations in Pten dose determine cancer susceptibility: Gene expression profiling for MEF cells from a Ptenhy/+ mouse model. We have analyzed the survival and tumor spectrum in a population of Pten ‘hypermorphic’ mice (Ptenhy/+), which express approximately 80% of total Pten protein. Notably, the Ptenhy/+ developed a spectrum of tumors of variable latencies, with breast tumors occurring at the highest penetrance. Surprisingly, all breast tumors analyzed retain two intact copies of Pten, and maintain Pten protein levels above that observed in heterozygosity. Importantly, subtle down-regulation of Pten was found to alter the expression profile of genes involved in cell proliferation. Taken together, our findings support the notion that initiation of tumorigenesis can occur in the absence of genetic hits, thereby questioning the uniqueness of a saltatory model for cancer susceptibility. In order to understand whether subtle variations in Pten level may affect pathways involved in tumorigenesis, we analyzed the genome-wide expression profile of Ptenhy/+ mouse embryonic fibroblasts (MEFs).
Project description:Comparison of the tumors PTEN promoter variant carrier and non carrier gene expression profiles. Expression profiles of 10 breast cancer patients with PTEN promoter variant and 10 controls matches for histology, ER, PR, T, N, M, Grade, HER2, Ki67, and p53.
Project description:A Cartes d'Identite des Tumeurs (CIT) project from the french Ligue Nationale Contre le Cancer (http://cit.ligue-cancer.net) | 74 samples on Affymetrix HG-U133 Plus 2.0 GeneChips arrays for 74 patients. 5 samples on CGH CIT v7 | Breast carcinoma is the main malignant tumor occurring in patients with Cowden disease, a cancer prone syndrome caused by germline mutation of the tumor suppressor gene PTEN. To better understand this disease, we have performed a transcriptomic study of three Cowden disease breast carcinomas included in a panel of 74 familial breast cancers. Unsupervised clustering of these 74 tumors followed the intrinsic gene classification of breast cancer except for a group of five tumors that included the three Cowden tumors. The gene expression profile of the Cowden tumors shows considerable overlap with that of a breast cancer subgroup known as molecular apocrine breast carcinoma, which is suspected to have increased androgenic signaling and shows frequent ERBB2 amplification. A histological and immunohistochemical study performed on 13 additional cases of Cowden disease breast carcinomas, for which RNA was not available, showed that they have apocrine histological features and express GGT1, a marker of molecular apocrine breast carcinoma. These data suggest that activation of the ERBB2-PI3K-AKT pathway by loss of PTEN at early stages of tumorigenesis promotes the formation of breast tumors with apocrine features. | Submitter : Renaud Schiappa schiappar@ligue-cancer.net | Project leader : Michel Longy longy@bergonie.org
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.