Abstract 2971: The prognostic relevance of inflammatory cytokines and growth factors elaborated from adipose-derived stem cells in breast cancer

Abstract

Introduction: Given the high rates of obesity and aggressive breast cancers, it is paramount to understand how adipose tissue supports the tumor microenvironment. We previously found that adipose-derived stem cells cultured with triple-negative tumor cells enhanced the expression of numerous pro-inflammatory cytokines. This finding is significant as it could explain, in part, how obesity contributes to worse outcomes in breast cancer. To further expand this study, we probed the Cancer Genome Atlas (TCGA) breast invasive carcinoma dataset for the expression profiles of the inflammatory cytokines we found to be highly up-regulated in vitro. We predicted TCGA data would demonstrate a correlation between cytokine overexpression and worse clinical scenarios.

Methods: Cytokines and growth factors were measured in the media of adipose stromal cells and MDA-MB-231 tumor cells via membrane-based antibody array. To validate clinical significance, we compared each cytokine’s mRNA expression profile, available from primary tumor samples of TCGA breast invasive carcinoma dataset (n = 1,005), to indices of tumor progression and survival status. For survival analysis, samples were dichotomized as high or low expression by individual cytokines (z score ≥ 1.5). Cytokine and growth factor expression was further stratified according to molecular subtype of breast cancer (luminal A, luminal B, HER2, triple negative) and receptor status. Ingenuity pathway analysis (IPA) was performed to identify candidate markers related to obesity or inflammation.

Results: High levels of FGF7 and CCL5 protein were found in the conditioned media of tumor and adipose stem cell co-cultures and together they showed a significant impact on breast cancer survival within TCGA data. FGF7, CCL5, together with CCL2, IL6, and IL6R were further analyzed for expression across molecular subtypes of breast cancer. IL6R, CCL5, and CCL2 expression varied significantly between breast cancer subtypes, with mean expression highest in triple-negative tumors. After dichotomizing the samples for estrogen receptor status, IL6R, CCL5, and CCL2 showed significantly higher mean expression in ER negative tumors. Greater expression of these cytokines in tumors was correlated with reduced patient survival in triple-negative tumors and ER negative subtypes. IPA analysis indicated IL6, IL6R, CCL5, and CCL2, but not FGF7, cooperate through inflammatory pathways to promote tumor progression.

Conclusions: Genomic data analysis supports in vitro findings that IL6R, CCL5, and CCL2 overexpression, either independently or synergistically, predict a worse prognosis in breast cancer. For adipose-driven, hormone receptor negative breast tumors, these cytokines and growth factors could serve as novel therapeutic targets. (Supported by NIH P20GM103434 and NIGMS U54GM104942)

Citation Format: Nicole Werwie, Kelsey Sadlek, Eric Lundstrom, Daniel Berrebi, Gerald Hobbs, Linda Vona-Davis. The prognostic relevance of inflammatory cytokines and growth factors elaborated from adipose-derived stem cells in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2971. doi:10.1158/1538-7445.AM2017-2971