Project description:The gene expression of 6 different mouse xenografts initiated by BPLER cells analyzed by microarray. Basal-like triple negative breast cancers (TNBC) have poor prognosis. To study the basal-like transcriptional profile of tumors transformed by defined genetic elements, the human breast epithelial cell line BPLER was injected into NOD/SCID mice. The resulting tumors were excised for expression analysis. Keywords: breast cancer, BPLER, metastasis, tumor stem cells, tumor initiating cells, breast adenocarcinoma BPLER cells were derived from human primary breast epithelial cells propagated in WIT medium (Ince et al, Cancer Cell, 2007). These cells were transformed with hTERT, SV40 early region and hRASV12 by retroviral transduction. BPLER have a TNBC-like phenotype in vitro and are highly enriched for tumor-initiating cells. To define the phenotype of BPLER-derived tumors in vivo, BPLER cells were injected in the mammary fat-pad of 6 NOD/SCID mice. Once tumors were palpable, mice were sacrificed and tumors excised. Total RNA was extracted using Trizol. The gene expression profile of each tumor was assessed by mRNA microarray analysis. Based on histology and principal component analysis of microarray data, BPLER tumors were remarkably similar to human primary TNBC encountered in the clinic (Petrocca et al, Cancer Cell, 2013).
Project description:The CD44hi compartment in human breast cancer is enriched in tumor-initiating cells, however the functional heterogeneity within this subpopulation remains poorly defined. From a human breast cancer cell line with a known bi-lineage phenotype we have isolated and cloned two CD44hi populations that exhibited mesenchymal/Basal B and luminal/Basal A features, respectively. Rather than CD44+/CD24-,Basal B (G4) cells, only CD44hi/CD24lo, epithelioid Basal A (A4) cells retained a tumor-initiating capacity in NOG mice, form mammospheres and exhibit resistance to standard chemotherapy. Microarray data obtained from Affymetrix Human Gene 1.0 ST Array Five replicates of A4 and 5 replicates of G4
Project description:The ability to predict metastatic potential is of clinical and biological importance. Numerous metastasis/relapse predictors exist for breast cancer patients; however, what is less well established is whether predicting metastasis to specific organs sites is feasible. In this study we sought to determine: 1) the degree to which gene signatures vary across tumors and their metastases, 2) if genomic intrinsic subtypes associate with particular organs of relapse, and 3) if other genomic signatures can predict spread to specific organs. Using a gene expression microarray data set of >1000 breast tumors and metastases, we observed that >90% of 298 gene signatures were similarly expressed between matched pairs of breast tumors and metastases; those most altered were reflective of cell types including fibroblasts and immune cells. Significant associations were identified between tumor subtypes and organ of first relapse. Among these, HER2-enriched tumors were significantly associated with liver, and Basal-like and Claudin-low tumors with brain and lung. Correspondingly, previously published brain and lung metastasis signatures, along with embryonic stem cell and tumor initiating cell signatures, were also associated with Basal-like and Claudin-low subtypes. These signatures strongly correlated with low Differentiation Scores (DS) and, to a lesser extent, high proliferation. Interestingly, within Basal-like and Claudin-low tumors, low DS further predicted for brain and lung metastases. In total, intrinsic subtype and DS provide clinically useful information that identifies the distant organ sites that should be most closely monitored for signs of disease recurrence. 414 samples profiled on Agilent microarrays.
Project description:The differentiation of stem-like cells of tumors may contribute to the cellular heterogeneity of breast cancers. We report the propagation of highly enriched mouse mammary cancer stem cells that retain the potential to differentiate both in vivo and in culture and their use to identify chemical compounds that influence both self-renewal and differentiation. We identify epithelial tumor initiating cells (ETIC) that expresses lineage markers of both basal and luminal mammary cell lineages and retains the potential to generate heterogeneous tumors similar to the tumor of origin from even single cells. ETIC can progress through a Rho associated coil-coil protein kinase 1 (ROCK1) dependent, epithelial to mesenchymal transition to generate a second cell type capable of initiating tumors of limited heterogeneity. The propagation of ETIC will increase the opportunities for identifying new therapeutic compounds that may inhibit or prevent progression of some types of breast cancer. These data compare the gene expression pattern of ETIC and MTIC. Total RNA obtained from ETIC and MTIC cells, allowing the comparison of gene expression patterns and the selection of potential targets.
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.