Abstract 3031: Angiotensin 1-7 up regulates apoptosis related genes and it preferentially targets differentiated epithelial breast cells

Abstract

Introduction: Renin Angiotensin System (RAS) components are not only related to breast cancer but also to other cancer types. Angiotensin-(1-7) [Ang-(1-7)] is an endogenous 7-amino acid peptide hormone of the renin-angiotensin system that has antiproliferative properties. The aim of this work is to analyze the action of Ang-(1-7) treatment in MCF-10F (normal) and in SKBR3 (tumoral) epithelial breast cells in their capacity to be droven to apoptosis, and also to assess the expression of the membrane receptors CD24 and CD44 in these cells. Methods: We used the SA Biosciences Human Apoptosis RT*2 Profiler PCR Array profiles to analyze the expression of 84 key genes involved in programmed cell death. Furthermore a flow cytometer (GUAVA) was used for quantification of the membrane proteins CD24 and CD44 in the MCF10F and in the SKBR3 breast cells after 24 hours of Angiotensin 1-7 stimulation. Results: Flow cytometric analysis using MCF10F cells showed that a 24h Ang1-7 stimulation period down regulates CD24 gene expression (about 43%) and it up regulates CD44 gene expression (about 16%). On the other hand there was no difference in the expression of both CD24 and CD44 proteins after Ang1-7 stimulation in SKBR3 tumoral cells. Furthermore, after the gene expression analysis by PCR Array, we found differential expression in MCF10F cells after Ang 1-7 treatment and we observed that the genes had their expression changed about 30% (2.1 to 514 fold increases) and 11% (2.6 to 3.8 fold decreases), respectively on a panel of 84 genes related to apoptosis. For SKBR3 cells, we found that the genes were altered in about 5.9% (2.6 to 5.4 fold increases) and 12% (2.1 to 3.3 fold decreases), respectively. Conclusion: Ang 1-7 appears to modulate the expression of membrane proteins CD24 and CD44 in MCF10F cells, also this hormone seems to induce apoptosis by inducing the expression of apoptosis related genes, such as, Abl1, Akt, Bax, Bcl2 (fold change, 3, 12, 6, and 6, respectively). Another important gene is the Hrk (harakiri, BCL2 interacting protein), that regulates apoptosis through interaction with death-repressor proteins Bcl-2 and Bcl-X(L), it displayed a fold change of 514. On the other hand in SKBR3 cells, comprised almost entirely by mammary stem cells, we found no regulation of CD24 and CD44 proteins by Ang1-7. Moreover, it was observed a very low differential expression in the genes related to the apoptosis pathway in these cells. However, the peptide Ang 1-7 seems to act preferentially in differentiated cells of the normal breast epithelium. Financial Support: FAPESP. 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 3031. doi:1538-7445.AM2012-3031