Abstract 52: Gene expression profiling of breast cancer associated fibroblasts and their adjacent counterparts

Abstract

Abstract Abstract Breast cancer has a major impact on the health of women worldwide including Saudi Arabia, where it is considered the most frequently diagnosed cancer (∼22% of all female cancers) and the leading cause of cancer deaths among women. Breast carcinomas are complex neoplasms that develop by the accumulation of different mutations in the epithelial cells. However, increasing evidence suggests that changes in the cellular microenvironment contribute to tumorgenesis through paracrine effects. Fibroblasts, the predominant cells of the stromal breast carcinomas, play an important role in the development and spread of cancer cells. However, the nature and the mediators of the crosstalk between cancer cells and their stromal fibroblasts are still not well defined. In this study we performed genome wide expression analysis on 5 Carcinoma-Associated Fibroblasts (CAFs) and their corresponding Tumor Counterpart Fibroblasts (TCFs) (from the same breast cancer patients) as compared to 3 normal breast fibroblasts (NBFs) from breast cancer free patients admitted for plastic surgery. To this end, Affymetix's latest Gene Chip® Human Genome U133 Plus 2.0 Array, which has more than 54,000 probe sets, was used. A threshold of ≤2≥ fold was considered as significant difference in the analysis of the microarray data. We performed 3 different comparisons; CAFs with TCFs, CAFs with NBFs and TCFs with NBFs. The analysis of the microarray data showed that the number of genes that were differentially expressed between CAFs and NBFs reached 101, and only 42 genes were differentially expressed between CAFs and TCFs. Interestingly, 77 genes were found to be differentially expressed between TCFs and NBFs. This data was confirmed by quantitative RT-PCR. Next, we used Ray Bio® Human cytokine Antibody Array 5 Map, which has 80 probed cytokines, and showed differential expression profile of different cytokines secreted by TCF, CAF and NBF cells, confirming that TCFs are different than CAFs and NBFs indicating that TCFs are indeed active stromal fibroblasts. Moreover, we examined the expression level of α-SMA, TGF-β and SDF-1 proteins (3 well known markers of active fibroblasts) and found their expression higher in TCFs than NBFs. In addition, we performed ELISA against SDF-1, VEGFA and IL-6 (3 cytokines known to promote breast carcinogenesis) and found their levels higher in TCFs than in NBFs conditioned media. Therefore, despite the fact that TCFs exist in histologically normal breast tissues, they are not physiologically normal, but rather present some features of active fibroblasts and thereby they may participate in breast cancer development / recurrence. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 52. doi:1538-7445.AM2012-52