Abstract 6067: Beta-2 adrenergic receptors role in tumor aggressiveness of triple negative breast cancer

Abstract

Abstract Breast cancer is the world's leading cause of cancer mortality among women. Despite advances in both diagnosis and treatment a large number of women die because of metastatic breast cancer. Research demonstrated a strong link between chronic stress and weakened immune system leaving the body prone to disease like cancer. Indeed, psychological stress has been shown to enhance tumor growth and progression. In addition, stress hormones, such as epinephrine, are implicated in the growth, invasiveness and metastasis of cancer. Therefore, targeting the beta-2 adrenergic receptor (ADRB2) in cancer chemoprevention may offer new promises for the design of therapeutic strategies. For that reason, we determine the cellular processes involved in ADRB2 mediated effects on human triple negative breast cancer cell line MDA-MB-231 in cultures and in xenograft tumors. In order to determine the effects of loss of expression of the gene, we suppressed ADRB2 by knock down, using CRISPR technology or, pharmacologically by employing general beta receptor blocker; propranolol and the beta-2 specific; ICI 188,551. Cell proliferation, migration and invasion assays were performed to define a degree of aggressiveness of the cell phenotype. Western Blot analysis on characteristics proteins of the epithelial-mesenchymal transition was used to further characterize the phenotype. PCR Array expression studies were done to analyze modifications of genes expression profile and signaling cascades in the ADRB2 inhibited cells. We found that an inhibition of ADRB2 receptors reduce proliferation, migration and colony formation of MDA-MB-231 cells. Additionally, ADRB2 knock down increased expression of epithelial proteins while decreased mesenchymal markers. The mRNA expression study targeting cancer stem cell genes showed that the inhibition of ADRB2 significantly modifies signaling pathways involved in cell movement, invasion, migration and proliferation such as Wnt/beta-catenin, ILK and Notch signaling. Within these signaling pathways, the expression of ILK and GSK3 seems to be critical. Indeed, we found that the inhibition of GSK3 by specific inhibitor SD-216763 reduced cell proliferation, migration and colony formation of MDA-MB-231 cells. Also, we found that GSK3 activator, Wortmanin, affected ADRB2 mediated cell proliferation, migration and colony formation of MDA-MB-231 cells. These data demonstrate that GSK3 is a downstream effector of the activation of ADRB2 receptor. Finally, the in vivo study showed a diminution of tumor volume and a better survival when RNU nude rats were treated daily with propanolol compared to control group. Preliminary data suggests propanolol treatment reduces GSK3 level in tumor tissues in association with a decrease in tumor growth. These data provide evidence for a role of ILK-GSK3 signaling in ADRB2 regulated breast tumor growth and aggressiveness. (Supported by NIH grant R01 CA20863201) Citation Format: Benedicte Rousseau, Sengottuvelan Murugan, Ajay Palagani, Ananya Tirupathur, Nupur Kadam, Dipak K. Sarkar. Beta-2 adrenergic receptors role in tumor aggressiveness of triple negative breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6067.