Integration of Molecular Profiling and Chemical Imaging to Elucidate Fibroblast-Microenvironment Impact on Cancer Cell Phenotype and Endocrine Resistance in Breast Cancer

Abstract

The tumor microenvironment is known to play a key role in altering the properties and behavior of nearby cancer cells. Its influence on resistance to endocrine therapy and cancer relapse, however, is poorly understood. Here we investigate the interaction of mammary fibroblasts and estrogen receptor-positive breast cancer cells in three-dimensional culture models in order to characterize gene expression, cellular changes, and the secreted protein factors involved in the cellular cross-talk. We show that fibroblasts, which are the predominant cell type found in the stroma adjacent to the cancer cells in a tumor, induce an epithelial-to-mesenchymal transition in the cancer cells, leading to hormone-independent growth, a more invasive phenotype, and resistance to endocrine therapy. Here, we applied a label-free chemical imaging modality, Fourier transform infrared (FT-IR) spectroscopic imaging, to identify cells that had transitioned to hormone-independent growth. Both the molecular and chemical profiles identified here were translated from cell culture to patient samples: a secreted protein signature was used to stratify patient populations based on gene expression and FT-IR was used to characterize breast tumor patient biopsies. Our findings underscore the role of mammary fibroblasts in promoting aggressiveness and endocrine therapy resistance in ER-positive breast cancers and highlight the utility of FT-IR for the further characterization of breast cancer samples.

Targeting the tumour stroma to improve cancer therapy

“…2e) 258 . Analysis of conditioned media from co-cultured cancer cells showed a >5-fold upregulation of 46 proteins (including MMPs and TGFβ) compared with media from non co-cultured breast cancer cells 258 .…”

“…2e) 258 . Analysis of conditioned media from co-cultured cancer cells showed a >5-fold upregulation of 46 proteins (including MMPs and TGFβ) compared with media from non co-cultured breast cancer cells 258 . Other studies have shown that the loss of caveolin 1 expression in breast cancer stromal tissue enables prediction of a lack of response to tamoxifen, an ER antagonist 259,260 .…”

Infrared spectroscopic imaging: Label-free biochemical analysis of stroma and tissue fibrosis

“…These relationships arise from the fact that stromal or abnormal fibrotic regions are often the surrounding environment in which pathologic processes of the epithelium take place. For example, FT-IR investigations of co-culture of fibroblasts with breast cancer cell lines highlight the interaction between the former and the latter (Holton, S. et al, 2011; Holton et al, 2014; Holton, S.E. et al, 2011).…”

Microenvironment and endocrine resistance in breast cancer: Friend or foe?

“…In particular they found that fibronectin, lysyl oxidase, SPARC and TIMP3 expression levels were associated to the prognosis of patients with breast cancer whereas levels of tenascin C were associated to resistance to treatment with tamoxifen. A recent paper by Holton et al [38] using 3D cultures and Fourier transform infrared spectroscopic imaging shows that fibroblasts induce epithelial to mesenchymal transition in cancer cells together with a downregulation in ERα levels. Our work also suggests that stromal factors modulate response to endocrine resistance.…”