Abstract 3444: Identification of Interleukin-1 (IL-1) induced gene expression pattern in breast cancer (BCa) cells

Abstract

Abstract Breast cancer (BCa) and prostate cancer (PCa) are both hormone driven cancers with similar etiology and tumor microenvironment inflammation promotes BCa and PCa progression. Interleukin-1 (IL-1) is an inflammatory cytokine present in the tumor microenvironment and IL-1 is elevated in BCa and PCa patient tumor and/or blood serum and correlates with poor prognosis. We have shown that IL-1 represses the BCa and PCa therapeutic targets, Estrogen Receptor Alpha (ERa) and Androgen Receptor (AR), respectively, in PCa and BCa cell lines; yet the cells remain viable. Thus, IL-1 may promote treatment resistance and disease progression. The pro-survival protein Sequestome-1 (SQSMT1/p62) is also upregulated in both BCa and PCa cell lines exposed to IL-1, suggesting that BCa and PCa cells have evolved a shared response to IL-1 and hormone receptor loss. RNA sequencing of an IL-1-treated PCa cell line revealed an IL-1-modulated gene suite predicted to confer AR-independent tumorigenicity. We performed RT-qPCR in PCa cell lines for several select genes to confirm the RNA sequencing results and given the similar etiology and IL-1 regulation of ERa, AR, and p62 expression in BCa and PCa cell lines, we presumed that our select genes would be similarly regulated by IL-1 in BCa cells. However, outside of ERa, AR, and p62 expression, our select genes did not show similar IL-1 regulation in BCa cell lines, suggesting that IL-1 regulates a unique set of genes that could contribute to ERa-independent tumorigenicity in BCa cells. Therefore, to identify a BCa-specific IL-1-modulated gene suite, we performed RNA sequencing on an IL-1-treated ERα+ BCa cell line and compared gene expression changes with 1) basal gene expression in an ERa- BCa cell line and 2) our IL-1-modulated PCa-specific gene suite. Our bioinformatics analysis revealed pathways that are predicted to promote ERa-independent tumorigenicity in BCa cells and investigations are underway to demonstrate the functional significance of our gene expression data. Taken together, our studies provide insight into the mechanistic function of IL-1 in PCa and BCa resistance to hormone receptor-targeted therapies and tumor progression. Citation Format: Afshan Fathima Nawas, Mohammed Kanchwala, Shayna Thomas-Jardin, Vanessa Anunobi, Ally Wong, Chao Xing, Nikki Delk. Identification of Interleukin-1 (IL-1) induced gene expression pattern in breast cancer (BCa) cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3444.