Abstract P2-05-07: RAGE-ligand signaling drives breast cancer metastasis through affecting cells of the tumor and microenvironment

Breast cancer is most common malignant state in women, with 20% of these patients developing metastasis during the course of their disease. Further understanding is needed of the process and mechanisms of metastasis. Our lab and others have been shown that Receptor of Advanced-Glycation End-products (RAGE) plays a role in tumorigenesis and metastasis. RAGE is highly expressed in various cancers including breast cancer and its protein levels correlate with poor patient outcome in breast cancer and other cancers. Activation of RAGE results in increased proliferation, migration and invasion of cancer cells. Further studies in mice have shown it may be a therapeutic target to reduce tumor growth and the resulting metastasis. Further understanding is needed of the role of RAGE in driving metastasis through affecting cells of both the tumor and tumor stroma to design novel therapeutics. Using the breast cancer cell model (MDA-MB-231) and its organotropic sister cells lines selected in vivo for increased metastasis to lung (4175) and bone (1833), we tested the role of RAGE in driving tumor metastasis in vitro and in vivo with xenograft mouse models. To test the role of RAGE in the tumor microenvironment we used the AT-3 syngeneic breast cancer cell model in C57BL6 wild-type and RAGE knockout mice. We demonstrated that the highly metastatic variant of 231 cells (4175 and 1833) have increased expression level of RAGE compared to MDA-MB-231 parental cells. Ectopic over-expression of RAGE in parental 231 cells led to increased migratory and invasive properties compared to vector control cells, without affecting cell proliferation or viability. RAGE knockdown by shRNA in 4175 and 231 parental cells showed decreased cell invasion in transwell assays compared to control scramble shRNA. To validate our data in vivo, we performed mammary fat pad injection of 4175 cells (RAGE and scr shRNA) in NOD SCID gamma mice. Tumor growth and weight was impaired in RAGE gene knockdown 4175 cells compared to scramble (scr) controls. Analysis of lung and liver tissue retrieved from mice revealed RAGE knockdown in 4175 cells prevented metastasis compared to 4175 scr control cells. To test the role of RAGE on non-tumor cells of the breast stroma we next performed syngeneic studies with AT-3 cells (MMTV-PyMT spontaneous BC cell model), by injection into the mammary fat pad of wild-type and RAGE knockout C57BL6 immunocompetent mice. RAGE knockout mice (RAGE -/-) displayed striking impairment of tumor cell growth compared to wild-type (RAGE +/+) mice. We are currently testing whether novel RAGE inhibitors impact breast cancer progression and metastasis. These data highlight RAGE drives breast cancer progression and metastasis through affecting both tumor cell intrinsic and non-tumor cell microenvironment effects. Future studies will demonstrate the potential of RAGE inhibition as a novel therapeutic approach for preventing and treating metastatic disease in breast and other cancers. Citation Format: Kwak T, Drews-Elger K, Ergonul A, Zhao D, Besser A, Slingerland JM, Lippman ME, Hudson BI. RAGE-ligand signaling drives breast cancer metastasis through affecting cells of the tumor and microenvironment. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-05-07.