Project description:Molecular profiling was used to classify mammary tumors that develop in MTB-IGFIR transgenic mice. It was determined that the primary mammary tumors (PMT), which develop due to elevated expression of the type I insulin-like growth factor receptor (IGF-IR) in mammary epithelial cells, most closely resemble murine tumors with basal-like or mixed gene expression profiles and with human basal-like breast cancers. Downregulation of IGF-IR transgene in MTB-IGFIR tumor-bearing mice leads to the regression of most of the tumors followed by tumor re-appearance in some of the mice. These tumors that re-appear following IGF-IR transgene downregulation do not express the IGF-IR transgene and cluster with murine mammary tumors that express a mesenchymal gene expression profile and with human claudin-low breast cancers. Therefore, IGF-IR overexpression in murine mammary epithelial cells induces mammary tumors with primarily basal-like characteristics while tumors that develop following IGF-IR downregulation express a gene signature that most closely resembles human claudin-low breast tumors. Three conditions: 8 wild type (WT) mammary glands, 11 primary mammary tumor (PMT) samples, 9 recurrent spindle tumor (RST) samples, each sample was hybridized against a universal mouse reference RNA
Project description:Molecular profiling was used to classify mammary tumors that develop in MTB-IGFIR transgenic mice. It was determined that the primary mammary tumors (PMT), which develop due to elevated expression of the type I insulin-like growth factor receptor (IGF-IR) in mammary epithelial cells, most closely resemble murine tumors with basal-like or mixed gene expression profiles and with human basal-like breast cancers. Downregulation of IGF-IR transgene in MTB-IGFIR tumor-bearing mice leads to the regression of most of the tumors followed by tumor re-appearance in some of the mice. These tumors that re-appear following IGF-IR transgene downregulation do not express the IGF-IR transgene and cluster with murine mammary tumors that express a mesenchymal gene expression profile and with human claudin-low breast cancers. Therefore, IGF-IR overexpression in murine mammary epithelial cells induces mammary tumors with primarily basal-like characteristics while tumors that develop following IGF-IR downregulation express a gene signature that most closely resembles human claudin-low breast tumors.
Project description:RNA was isolated from mammary glands from 55 day old control mice, mice overexpressing the miR-200b/200a/429 cluster in mammary epithelial cells (MTB-200ba429) mice overexpressing the IGF-IR transgene in mammary epithelial cells (MTB-IGFIR), and mice overexpressing both the miR-200b/200a/429 cluster and the IGF-IR transgene in mammary epithelial cells (MTB-IGFIRba429)
Project description:LH-overexpressing mice display elevated levels of mammogenic hormones and consequently develop spontaneous mammary tumors with a median latency of 41 weeks. Tumors occur in the absence of p53 mutations and in the presence of a seemingly functional p53 signaling pathway. At 16 weeks of age, no histological evidence of tumors is observed in these transgenic mammary glands; however, mammary cells do demonstrate centrosome amplification at this age suggesting that early tumorigenic processes may have occured. Thus comparison of the transcriptome of the mammary glands from 16 week old LH-overexpressing mice to that of wild type mice will provide insight into early events occuring in p53-independent hormone-induced tumorigenesis. Experiment Overall Design: Total RNA was isolated from mammary glands of a total of 9 wild type and 9 transgenic mice. RNA from 3 mammary glands was pooled together generating 3 wild type samples and 3 transgenic samples.
Project description:LH-overexpressing mice display elevated levels of mammogenic hormones and consequently develop spontaneous mammary tumors with a median latency of 41 weeks. Tumors occur in the absence of p53 mutations and in the presence of a seemingly functional p53 signaling pathway. At 16 weeks of age, no histological evidence of tumors is observed in these transgenic mammary glands; however, mammary cells do demonstrate centrosome amplification at this age suggesting that early tumorigenic processes may have occured. Thus comparison of the transcriptome of the mammary glands from 16 week old LH-overexpressing mice to that of wild type mice will provide insight into early events occuring in p53-independent hormone-induced tumorigenesis. Keywords: disease state analysis
Project description:Overexpression of ECD in mammary gland promotes mammary tumorigenesis. To determine the plausible mechanism of how ECD contributes the oncogenesis, we performed RNAseq analysis of three independent control mice mammary glands (6 months old) and four independent ECD transgenic mammary tumors. Out of these four tumors, T1a and T1b were adenosquamous carcinoma type, T3 was Spindle cell carcinoma type and T4 was papillary carcinoma. RNA was isolated from the respective samples and RNAseq was performed.
Project description:Although estrogen receptor (ER) and insulin-like growth factor (IGF) signaling are important for normal mammary development and breast cancer, cross-talk between these pathways, particularly at the level of gene transcription, remains poorly understood. We performed microarray analysis on MCF-7 breast cancer cells treated with estradiol (E2) or IGF-I for 3hr or 24hr. IGF-I regulated mRNA of 5-10-fold more genes than estradiol, and many genes were co-regulated by both ligands. Importantly, expression of these co-regulated genes correlated with poor prognosis of human breast cancer. Closer examination revealed enrichment of repressed transcripts. Interestingly, a number of potential tumor suppressors were down-regulated by IGF-I and estradiol. In fact, BLNK, one of the top repressed genes, is a potential growth suppressor in breast cancer cells. Analysis of three down-regulated genes showed that E2-mediated repression occurred independently of IGF-IR, and IGF-I-mediated repression occurred independently of ER. However, repression by IGF-I or estradiol required common downstream kinases. In conclusion, E2 and IGF-I co-regulate a set of genes that affect breast cancer outcome. There is enrichment of repressed transcripts, and the down-regulation is independent at the receptor level. This may be important clinically, as tumors with active ER and IGF-IR signaling may require co-targeting of both pathways. KEYWORDS: multiple group comparison Microarray analysis on MCF-7 breast cancer cells treated with estradiol (E2) or IGF-I for 3hr or 24hr.
Project description:Although estrogen receptor (ER) and insulin-like growth factor (IGF) signaling are important for normal mammary development and breast cancer, cross-talk between these pathways, particularly at the level of gene transcription, remains poorly understood. We performed microarray analysis on MCF-7 breast cancer cells treated with estradiol (E2) or IGF-I for 3hr or 24hr. IGF-I regulated mRNA of 5-10-fold more genes than estradiol, and many genes were co-regulated by both ligands. Importantly, expression of these co-regulated genes correlated with poor prognosis of human breast cancer. Closer examination revealed enrichment of repressed transcripts. Interestingly, a number of potential tumor suppressors were down-regulated by IGF-I and estradiol. In fact, BLNK, one of the top repressed genes, is a potential growth suppressor in breast cancer cells. Analysis of three down-regulated genes showed that E2-mediated repression occurred independently of IGF-IR, and IGF-I-mediated repression occurred independently of ER. However, repression by IGF-I or estradiol required common downstream kinases. In conclusion, E2 and IGF-I co-regulate a set of genes that affect breast cancer outcome. There is enrichment of repressed transcripts, and the down-regulation is independent at the receptor level. This may be important clinically, as tumors with active ER and IGF-IR signaling may require co-targeting of both pathways. KEYWORDS: multiple group comparison