Abstract LB-501: Role of HGF in epithelial-stromal cell interactions during progression from benign breast disease to ductal carcinoma in situ

Abstract

Abstract Role of HGF in epithelial-stromal cell interactions during progression from benign breast disease to ductal carcinoma in situ. Introduction: Tumor-stroma interactions create a ‘permissive microenvironment’ during cancer progression. Basal and luminal breast cancers (BC) have distinct tumor-stroma interactions, but few studies show how gene expression evolves in premalignant cells. We observed that hepatic fibrosis/HGF signaling is induced in basal-like microenvironments, and previous studies have demonstrated that overexpression of HGF is a predictor of breast cancer recurrence and survival. However it is not known whether HGF signaling is altered in early (premalignant and DCIS) lesions. Methods: To study tumor-stroma interactions during cancer progression, we cocultured breast fibroblasts with a panel of isogenic cell lines, the MCF10 series. The MCF10 series represents different stages of cancer progression (benign, atypical hyperplasia and ductal carcinoma in situ). RNA from cocultures was used to perform gene expression microarrays and proteins secreted into media were analyzed by antibody arrays. Differentially expressed genes were identified using supervised analysis, followed by gene ontology analysis. In addition, a signature of basal-like microenvironment was evaluated to test whether the stroma-epithelial interactions observed in basal-like cancers were also present in premalignant cells. Finally, HGF signaling was inhibited (using an HGF-antibody) to assess effects of this pathway on migration and gene expression. Results: Cocultures with MCF10DCIS express higher levels of RNA involved in immune response processes and connective tissue disorders, as reported previously for basal-like BC. In contrast, premalignant MCF10AT and MCF10A cells showed weak expression of these profiles. In cytokine arrays, striking overexpression of HGF was observed in both MCF10AT1 and MCF10DCIS cocultures relative to cocultures with the benign MCF10A cell line, with corresponding increases in c-MET levels. These changes correlated with increased migration, which was blocked by adding HGF-specific antibodies to the media. Conclusions: Inhibition of HGF alters stromal-epithelial interactions, rendering the premalignant microenvironment more similar to normal microenvironments. HGF signaling is necessary for stroma-induced migratory phenotypes in vitro and is induces widespread gene expression changes. Targeting HGF signaling in early carcinogenesis may have value in preventing progression of basal-like precursor lesions. 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 LB-501. doi:1538-7445.AM2012-LB-501