Project description:The tumor suppressor gene p53 is frequently mutated in human breast cancer and is a marker for poor prognosis and resistance to chemotherapy. Transplantation of p53-null mouse mammary epithelium into syngeneic wild-type mice leads to normal mammary gland development followed by spontaneous mammary tumors that recapitulate many of the phenotypic, molecular, and genetic features of human breast cancer. Using this genetically engineered mouse model, we have examined the molecular mechanisms underlying tamoxifen-dependent tumor prevention. To determine whether the changes observed in the ERα cistrome after tamoxifen exposure are reflected in changes in estrogen responsive gene signatures in p53-null mammary epithelial cells (MECs), we performed global gene expression analysis by microarray profiling of MECs isolated from control and tamoxifen-exposed mice 4 weeks after tamoxifen withdrawal and treated with E2 for 8h. We identified 245 differentially regulated genes (P<0.01 and FC>1.4). Of these, 177 genes (72%) were persistently upregulated and 68 genes (28%) were persistently downregulated after transient exposure to tamoxifen. These results indicate that transient exposure to tamoxifen leads to lasting intrinsic changes in gene expression profiles of p53-null mammary epithelial cells that persist after tamoxifen withdrawal.
Project description:Total RNA was extracted from five million wild type (WT) and p53 knockout (p53_KO) MCF10A cells using Qiagen RNAeasy kit. Ribosomal RNAs were removed and the rest of RNAs were subject to RNAseq.
Project description:p53 is a pivotal tumor suppressor and a major barrier against cancer. We now report that silencing of the Hippo pathway tumor suppressors LATS1 and LATS2 in non-transformed mammary epithelial cells reduces p53 phosphorylation and increases its association with the p52 NF-?B subunit. Moreover, it partly shifts p53âs conformation and transcriptional output towards a state resembling cancer-associated p53 mutants, and endow p53 with the ability to promote cell migration. Notably, LATS1 and LATS2 are frequently downregulated in breast cancer; we propose that such downregulation might benefit cancer by converting p53 from a tumor suppressor into a tumor facilitator. MCF10A cells transfected with siRNA against LATS1/2 alone, p53 alone or LATS1/2 and p53 together. Two independent MCF10A batches provided biological replicates
Project description:MicroRNAs are noncoding, endogenous small RNAs that regulate target genes by cleavage of the targeted mRNA or translational repression. We investigated the microRNAome using 2-color microarrays in a highly invasive human breast cancer cell line, MDA-MB-231 (sub line 4175) and a non-invasive breast epithelial cell line, MCF10A. We found 13 miRNAs that were up-regulated and 9 were down-regulated significantly in 4175 cells (p <0.05, fold change >2) compared with MCF10A cells. We compared the highly metastatic human breast cell lines MDA-MB-231 (4175 subline) with non-metastatic MCF10A cell lines. Two 4175 sublines and two MCF10A cell lines, independently grown and harvested. Dye swap was performed.
Project description:MicroRNAs are noncoding, endogenous small RNAs that regulate target genes by cleavage of the targeted mRNA or translational repression. We investigated the microRNAome using 2-color microarrays in a highly invasive human breast cancer cell line, MDA-MB-231 (sub line 4175) and a non-invasive breast epithelial cell line, MCF10A. We found 13 miRNAs that were up-regulated and 9 were down-regulated significantly in 4175 cells (p <0.05, fold change >2) compared with MCF10A cells.
Project description:Examination of Pin1-regulated Myc target genes in a human breast epithelial cell line. Two samples: control GFP-expressing MCF10A-Myc cells and Pin1-expressing MCF10A-Myc cells.
Project description:We performed ChIP-seq analysis of p53-null HCT116 cells stably expressed wild-type p53 or mutant p53 followed by ATO treatment (PANDAs) to identify p53 binding characteristics by wild-type p53 and PANDAs.
Project description:To investigate how pleiotropic the impact of p53 loss is on cellular function, generated isogenic, polyclonal wild-type (sgNTC) and p53-null (sgp53) E1A;HrasG12V mouse embryonic fibroblast cell lines using CRISPR/Cas9. Here we show gene expression analysis on p53 wild-type (sgNTC) and p53null (sgp53) E1A;HrasG12V MEFs grown under physiological oxygen conditions (5% oxygen).
