Project description:The transcriptional profile of WapCre;Rank;Brca1;p53 and WapCre;Brca1;p53 mouse primary mammary tumor cells was determined by mRNA sequencing and uncovered differences in their molecular signatures including genes involved in oncogenesis, basic metabolism, RNA metabolism, or the regulation of mammary stem cells.
Project description:We have studied in vivo responses of spontaneous Brca1- and p53-deficient mouse mammary tumors to treatment with doxorubicin, docetaxel or cisplatin.
Project description:Breast cancers that are “triple-negative” for the clinical markers ESR1, PGR, and HER2 typically belong to the Basal-like molecular subtype. Defective Rb, p53, and Brca1 pathways are each associated with triple-negative and Basal-like subtypes. Our mouse genetic studies demonstrate that the combined inactivation of Rb and p53 pathways is sufficient to suppress the physiological cell death of mammary involution. Furthermore, concomitant inactivation of all three pathways in mammary epithelium has an additive effect on tumor latency and predisposes highly penetrant, metastatic adenocarcinomas. The tumors are poorly differentiated and have histologic features that are common among human Brca1-mutated tumors, including heterogeneous morphology, metaplasia, and necrosis. Gene expression analyses demonstrate that the tumors share attributes of both Basal-like and Claudin-low signatures, two molecular subtypes encompassed by the broader, triple-negative class defined by clinical markers. These studies establish a unique animal model of aggressive forms of breast cancer for which there are no effective, targeted treatments. Rb, p53, and Brca1 are associated with inherited forms of cancer, but defects in these pathways are also found together in a subset of breast cancer patients without a family history of the disease. Simultaneous inactivation of all three pathways causes more aggressive disease than do pair-wise combinations, indicating that the pathways play non-overlapping roles in tumor prevention. We investigated the effect of perturbation of Rb family pathways, p53, and/or Brca1 in mouse mammary epithelium. Eighteen tumors were compared to normal spleen DNA.
Project description:We compared the expression levels of X-linked genes in the mammary glands of Brca1 D11/D11;p53+/- mutant and control (p53+/-) mice at three different stages of the mammary cycle: virgin, pregnant day 16.5, and lactation day 1, using a cDNA microarray. In about 690 X-linked genes that are expressed at these three stages of mammary cycle of development, we found 16 X-linked genes showed altered expression levels in Brca1 D11/D11;p53+/- mammary glands in comparison with controls at all three time points. Among them, 9 genes were up-regulated and 7 were down-regulated. This result indicates that mutation of Brca1 could affect expression of a few X-linked genes in mammary tissues. However, this was unlikely caused by failure of X chromosome inactivation, as seven of them were down-regulated, and Xist RNA was expressed in all the Brca1 mutant mammary tissues. Keywords: BRCA1 mutation analysis
Project description:Gene expression profiles of "spontaneous" and transplanted topotecan-resistant BRCA1;P53-deficient mammary tumors and their matched untreated controls
