Differential gene profiling of malignant cells and fibroblasts from the primary and metastatic sites from breast cancer patients upon stroma-epithelial cell interaction

Abstract

10570 Background: In breast cancer (BC), stromal-epithelial cell interactions may influence tumor development in the primary tumor (PT) and metastatic sites, which may be reflected by a differential phenotype of malignant cells and fibroblasts (Fb). Methods: To investigate the role of stromal cell interactions in tumor development in the primary site and in lymph nodes (LN), primary culture of Fb obtained from breast tissue: PT (n = 4) or peritumoral (n = 4); and LN: involved (iLN, n = 3) or uninvolved (n = 3) from BC patients, were established. Fb and normal (MCF10A) or malignant breast cells (MDA-MB231) were cultured isolated or co-cultured separated by a porous membrane, for diffusion of soluble factors. Gene profile of epithelial cells or Fb were analyzed separately in cDNA microarray slides. Gene expression of co-cultured cells were compared to that of cells cultured alone and differentially expressed genes were those satisfying a FDR <0.01 and > 2 fold variation. Genes exclusively regulated during malignant conditions (MDA-MB231 cells co-cultured with Fb from PT or iLN) were selected on Venn diagrams. Results: Gene profile from MDA-MB231 cells may be influenced by Fb from the PT as 74 genes were differentially expressed upon co-culture as compared to MDA-MB231 cells maintained alone, including genes involved in DNA metabolism and regulation of transcription. Ninety nine genes were modulated in MDA-MB231 cells co-cultured with Fb from iLN, as those involved in RNA metabolism, phosphate metabolism and protein catabolism. Only 2 genes were commonly down-regulated in malignant cells upon co-culture with Fb from PT and iLN, KATNB1 and ZNF19, which modulation seem important for tumor development in both sites. In addition, malignant cells differentially affect gene expression of Fb from PT or iLN. Conclusions: Upon co-culture between Fb obtained from PT and iLN with malignant cells, a reciprocal regulation of a differential group of genes was observed, which may be important for tumor development in these different sites. This model may allow identification of candidate genes involved in stromal-cell interactions during tumor development in PT or LN. Supported by FAPESP and CNPQ. No significant financial relationships to disclose.