Project description:To identify genes that may facilitate early steps of ErbB2/Neu-mediated mammary tumorigenesis, we performed comparative microarray analysis of 5- and 10-week bitransgenic mammary glands (LHxMMTV-neu) in triplicate. Keywords: transgenic mouse, erbB2, MMTV-neu, HER2, mammary tumor, breast cancer
Project description:Breast cancer is a heterogeneous disease encompassing a number of phenotypically diverse tumours. Expression levels of the estrogen, progesterone and HER2/neu receptors which characterise clinically distinct breast tumors have been shown to change during disease progression and in response to systemic therapies. Mi(cro)RNAs play critical roles in diverse biological processes and are aberrantly expressed in several human neoplasms including breast cancer, where they function as regulators of tumour behaviour and progression. The aims of this study were to identify miRNA signatures that accurately predict the oestrogen receptor (ER), progesterone receptor (PR) and HER2/neu receptor status of breast cancer patients to provide insight into the regulation of breast cancer phenotypes and progression. Expression profiling of 353 microRNAs was performed in 29 early stage breast cancer specimens. MiRNA signatures associated with ER, PR and HER2/neu status were generated using artificial neural networks (ANN) and expression of specific microRNAs was validated using RQ-PCR. Results: Stepwise artificial neural network (ANN) analysis identified predictive miRNA signatures corresponding with estrogen (miR-342, miR-299, miR-217, miR -190, miR-135b, miR-218), progesterone (miR-520g, miR-377, miR-527-518a, miR-520f-520c) and HER2/neu (miR-520d, miR-181c, miR-302c, miR-376b, miR-30e) receptor status. MiR-342 and miR-520g expression was further analysed in 95 breast tumours. MiR-342 expression was highest in ER and HER2/neu positive luminal B tumours and lowest in triple-negative tumours. MiR-520g expression was elevated in ER and PR negative tumours.
Project description:MicroRNAs (miRNAs) are small, non-coding, endogenous RNAs involved in many human diseases including breast cancer. miRNA expression profiling of human breast cancers has identified miRNAs related to the clinical diversity of the disease and potentially provides novel diagnostic and prognostic tools for breast cancer therapy. In order to further understand the roles of miRNAs in association with oncogenic drivers and in specifying sub-types of breast cancer, we performed miRNAexpression profiling on mammary tumors from eight well-characterized genetically -engineered Mouse (GEM) models of human breast cancer including MMTV–H-Ras, -Her2/neu, -c-Myc, -PymT, –Wnt1 and C3(1)/SV40 T/t-antigen transgenic mice, BRCA1fl/fl;p53+/-;MMTV-cre and the p53fl/fl ;MMTV-cre transplant model. miRNA expression data for 41 mouse primary mammary tumors and 5 mouse normal mammary glands
Project description:MicroRNAs (miRNAs) are small, non-coding, endogenous RNAs involved in many human diseases including breast cancer. miRNA expression profiling of human breast cancers has identified miRNAs related to the clinical diversity of the disease and potentially provides novel diagnostic and prognostic tools for breast cancer therapy. In order to further understand the roles of miRNAs in association with oncogenic drivers and in specifying sub-types of breast cancer, we performed miRNAexpression profiling on mammary tumors from eight well-characterized genetically -engineered Mouse (GEM) models of human breast cancer including MMTV–H-Ras, -Her2/neu, -c-Myc, -PymT, –Wnt1 and C3(1)/SV40 T/t-antigen transgenic mice, BRCA1fl/fl;p53+/-;MMTV-cre and the p53fl/fl ;MMTV-cre transplant model. As supplementary data miRNA expression data for 3 mouse primary mammary tumors and 8 mouse normal mammary glands from different mouse strains
Project description:Breast cancer is a heterogeneous disease encompassing a number of phenotypically diverse tumours. Expression levels of the estrogen, progesterone and HER2/neu receptors which characterise clinically distinct breast tumors have been shown to change during disease progression and in response to systemic therapies. Mi(cro)RNAs play critical roles in diverse biological processes and are aberrantly expressed in several human neoplasms including breast cancer, where they function as regulators of tumour behaviour and progression. The aims of this study were to identify miRNA signatures that accurately predict the oestrogen receptor (ER), progesterone receptor (PR) and HER2/neu receptor status of breast cancer patients to provide insight into the regulation of breast cancer phenotypes and progression.
Project description:We identified a 17-gene Her2-enriched tumor initiating cell (HTIC) signature in MMTV-Her2/Neu mouse mammary TICs. Here, we show that patients with HTICS+ HER2+:ERα− tumors are more likely to achieve a pathologic complete response to trastuzumab-based neoadjuvant chemotherapy compared with HER2+:ER+ tumors. Neoadjuvant study of 50 HER2-positive breast cancer cases treated with trastuzumab-based chemotherapy pre-operatively. Pre-treatment FNA from primary tumors were obtained and RNA extracted and hybridized to Affymetrix microarrays according to manufacturer protocol. Pathologic response was assessed at the end of neoadjuvant treatment.
Project description:Murine models of mammary cancers have proven to be highly informative on numerous fronts including individual gene causation, microenvironmental analyses, and chemoprevention studies. The MMTV-Neu transgenic model of mammary cancer has proven to be a useful model and has been employed in several prevention studies. However, there are certain practical drawbacks to its use including long tumor latencies and a tendency to develop mutations in the transmembrane domain of Neu (unlike human HER2/Neu overexpressing breast cancers). Here we report modifications that were made in an attempt to optimize this mouse model for chemopreventive screening. First, homozygous MMTV-Neu and homozygous P53 KO mice were crossed to create a MMTV-Neu/P53+/- strain (which more closely approximates the genetic make-up of most HER2+ human patients). Second, to overcome the drawback of long tumor latencies, the mice were treated with DMBA for eight weeks. DMBA treatment greatly decreased the latency of mammary carcinomas in the MMTV-Neu mice although the resulting tumors remained histopathologically similar to those from MMTV-Neu control mice. Next, we examined gene expression in tumors derived from MMTV-Neu, MMTV-Neu/p53+/-, and DMBA treated mice. It was found that the characteristic MMTV-Neu tumor-defined expression pattern was still the most prevalent feature of all the MMTV-Neu tumors despite their being crossed to the p53 null allele, treated with DMBA, or both. However, tumors from the DMBA treated animals exhibited many unique gene expression changes including the high expression of stress response, defense, and inflammation genes. Finally, we demonstrated that the RXR agonists UAB30 and Targretin, both inhibited mammary cancer formation in MMTV-Neu mice, including those treated with DMBA. These results demonstrate the potential utility of this murine model for additional chemoprevention studies.
Project description:HER2 / Neu is amplified and overexpressed in a large proportion of human breast cancers, but the signaling pathways that contribute to tumor development and metastatic progression are not completely understood. Using gene expression data and pathway signatures we predicted a role for activator E2F transcription factors in Neu induced tumors. This was genetically tested by interbreeding Neu transgenics with knockouts of the three activator E2Fs. Loss of any E2F delayed Neu induced tumor onset. E2F1 loss accelerated tumor growth while E2F2 and E2F3 loss did not. Strikingly, it was observed that loss of E2F1 or E2F2 significantly reduced the metastatic capacity of the tumor and this was associated with a reduction in circulating tumor cells in the E2F2 knockout. Gene expression analysis between the tumors in the various E2F mutant backgrounds revealed that there was extensive compensation by other E2F family members in the individual knockouts, underscoring the importance of the E2Fs in HER2 / Neu induced tumors. Extension to HER2 positive human breast cancer revealed a number of HER2+ subtypes based on E2F activity with differences in relapse free survival times. Taken together these data demonstrate that the E2F transcription factors are integral to HER2+ tumor development and progression.