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: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:CNV profiling of tumors obtained from our Chaos3 mouse model for spontaneous breast cancer. The goal of this experiment was to determine copy number variations that were specific to MTs derived from this mouse model, when comapared to non-MTs.
Project description:Decremental loss of PTEN results in cancer susceptibility and tumor progression. In turn this raises the possibility that PTEN elevation might be an attractive option for cancer prevention and therapy. We have generated several transgenic mouse lines with variably elevated PTEN expression levels, taking advantage of BAC (Bacterial Artificial Chromosome)-mediated transgenesis. Super-PTEN mutants are viable and show reduced body size due to decreased cell number, with no effect on cell size. Unexpectedly, PTEN elevation at the organism level results in healthy metabolism characterized by increased energy expenditure and reduced body fat accumulation. Cells derived from these mice show reduced glucose and glutamine uptake, increased mitochondrial oxidative phosphorylation, and are resistant to oncogenic transformation. Mechanistically we find that PTEN elevation orchestrates this metabolic switch by regulating PI3K-dependent and independent pathways, and negatively impacts two of the most pronounced metabolic features of tumor cells: glutaminolysis and the Warburg effect. In order to elucidate the pathophysiological impact of PTEN elevation, we generated transgenic mice carrying additional copies of this critical tumor suppressor gene (referred to as Super-PTEN mice). In order to maintain the regulation properties of the endogenous Pten gene, we made use of large genomic fragments containing the entire Pten locus carried by BACs (Bacterial Artificial Chromosomes). We next generated mouse embryonic fibroblasts (MEFs) and confirmed successful overexpression of PTEN by the BAC transgenic system. Primary cells derived from Super-PTEN mice represent a powerful tool to elucidate the molecular mechanisms underlying dose-dependent PTEN actions. We therefore performed microarray analysis in primary cells (MEFs) derived from day 13.5 embryos obtained by crossing Super-PTEN mice with C57BL6 mice. Three independent embryos from each genotype were analyzed (background: >98%C57BL6 / CBA). Gene expression profile analysis in these cells will reveal target genes and pathways differentially regulated upon PTEN elevation.
Project description:PB-Cre/Pten/Smad4 is a transgenic mouse model of metastatic prostate adenocarcinoma (PMID: 21289624). To study the transcriptomic alterations associated with castration-resistant prostate cancer (CRPC), the PB-Cre/Pten/Smad4 males with established prostate cancer were treated with surgical castration followed by enzalutamide-admixed diet. After about 4 weeks, dorsolateral prostate (DLP) lobes of treatment-naïve prostate tumors (N=2) and CRPC tumors (N=3) were harvested and extracted for RNA purification and microarray profiling. To further study the transcriptomic changes associated with lung metastases of the PB-Cre/Pten/Smad4/mTmG CRPC model, the PB-Cre/Pten/Smad4 males with established prostate cancer were treated with surgical castration followed by enzalutamide-admixed diet. About 3 months later, from one mouse anterior prostate (AP), dorsolateral prostate (DLP), ventral prostate (VP) and GFP+ lung metastasis nodules were each harvested for RNA purification and microarray profiling.
Project description:Yap1 is a critical transcription coactivator in the Hippo pathways. However, its target genes are not well defined in prostate cancer cells. To determine the downstream transcriptional targets and pathways of Yap1 in Pten/Smad4-defiicent mouse prostate cancer cells, ChIP-seq was performed in the Pten/Smad4-deficient mouse prostate cancer cells.
Project description:MicroRNA profiling in Pten knockout mouse thymus cells. microRNAs (miRs) are short noncoding RNAs of 20â22 nucleotides that function to regulate gene expression at the posttranscriptional level. They play fundamental roles in the regulation of cellular proliferation, differentiation, and apoptosis. miRs are dysregulated in many types of cancer, including T-ALL (T cell lymphoblastic leukemia). miRs can function as oncogenes, favoring the initiation and progression of cancers, or as tumor suppressors, preventing tumorigenesis. The biological functions of miRs in T-ALL are largely unknown. In human T-ALL patients, recurrent mutations in the Phosphatase and tensin homolog (PTEN) gene are common, consistent with Pten-knockout mice developing T-ALL. To better understand T-ALL pathogenesis and identify new therapeutic targets in T-ALL, we developed a Pten-knockout T-ALL mouse model and the mice developed T-ALL within 3 months as expected. We profiled the miRs in the Pten-deficient mouse T-ALL. A576, A577, A578 and A579 are PTEN-knockout mouse T-ALL samples. A580 andA 581 are wild-type mouse thymocytes.
Project description:It is well-described that the tumor stroma participates in cancer progression, but whether stromal factors can initiate breast tumorigenesis remains unclear. Using our previously described stromal-specific phosphatase and tensin homolog (PTEN) deletion mouse model, we investigated transformative events in young, non-tumor bearing animals. Here, we show stromal PTEN deletion initiates radiation-induced genomic instability on neighboring mammary epithelium through paracrine epidermal growth factor receptor (EGFR) activation. In these mice, a single low dose of whole-body radiation induces mammary hyperplasia, a result that is prevented by pre-treatment with an EGFR inhibitor. We reveal that stromal PTEN is lost in a subset of normal breast samples and is predictive of recurrence in breast cancer patients. Combined, these data suggest both diagnostic and therapeutic chest wall radiotherapy may inadvertently predispose patients with focal stromal PTEN loss to secondary breast cancer, and that this predisposition may be treated prophylactically through EGFR inhibition.
Project description:SRC-2 is frequently amplified or overexpressed in metastatic prostate cancer patients. In this study, we used genetically engineered mice, overexpressing SRC-2 specifically in the prostate epithelium as a mouse model to examine the role of SRC-2 in prostate tumorigenesis. Over-expression of SRC-2 in PTEN heterozygous mice accelerates PTEN mutation induced tumor progression and develops a metastasis-prone cancer. We used microarrays to examine the molecular profile of prostate-specific SRC-2 overexpression adult dorsal-lateral prostate in comparison with that of control PTENF/+ heterozygous deletion mice. Total RNA was extracted from dorsal-lateral prostate of 7 months old-PTEN flox/+ control and PTEN flox/+; Rosa26-SRC-2 OE/+ adult mice, followed by gene expression profiling using Affymetrix microarrays. Each sample contains pooled prostate RNA from 3 mice.
Project description:Transcriptional profiling of mouse Th17 cells comparing WT Th17 cells with Pten-deficient Th17 cells. Naïve CD4 T cells from each mice were cultured Th17 polarizing condition for 3 days. Goal was to determine the effects of Pten on global gene expression.