Abstract A20: Investigating gene expression alterations in the tumor microenvironment based on receptor status in breast cancer using a microfluidic multiculture platform

Numerous cellular influences regulate the behavior of cancer cells, contributing to an orchestration of responses to stimuli within the tumor microenvironment. Development of novel therapies and drug targets specific to tumor receptor status in breast cancer necessitate the understanding of tumor microenvironment interactions. The current four tumor subgroups based on receptor status differ in tumor grade, recurrence and metastasis making these tumor types unique to one another in their microenvironments. Of particular interest, the HER2+ subgroup, is associated with higher recurrence, metastasis and poor prognosis. Microfluidic multi-culture techniques provide the opportunity to manipulate multiple cell types in a highly-controlled fashion, permitting evaluation of the tumor microenvironment that is not possible in traditional culture techniques. Utilizing a microfluidic multi-culture platform, where we have the ability to culture more than two cell types in compartmentalized culture chambers separated by diffusion ports to allow for soluble factor exchange, the HER2+ breast carcinoma cell lines SKBR3 (HER2+/ER-/PR-), and BT474 (HER2+/ER+/PR+) were cultured in co- and tri-culture combinations with bone marrow stroma, human mammary fibroblast, and the human M2 monocyte lines to examine signaling interactions between cancer, fibroblast and immune cell types. Gene expression changes of tumor progression markers were then evaluated using RT-qPCR for a constellation of growth factors, receptors and cytokines. Importantly, this new device allows isolation and gene expression analysis of individual cell types subsequent to culture without the need for downstream cell separation techniques. Significant changes in gene expression of the two breast cancer cell lines were detected in multi-culture that was dependent on the tumor microenvironment. Differences in gene expression between the cancer cells based on receptor status in multi-culture were also shown. These findings suggest that both the tumor microenvironment and receptor status may be interrelated and together influence tumor progression. The use of a micro multi-culture platform allows one to easily recapitulate individual complex tumor microenvironments. Even in as simple a model as two or three cell types, shapes tumor responses, which can now be rapidly dissected using this model system. Micro multi-culture techniques have the potential to provide insight on essential tumor microenvironment interactions that would otherwise be difficult to detect in traditional culture methods, paving the way for the design of new and personalized therapies. Citation Format: Lindsey J. Maccoux, Emma M. Weinberger, Scott M. Berry, Elaine T. Alarid, David J. Beebe. Investigating gene expression alterations in the tumor microenvironment based on receptor status in breast cancer using a microfluidic multiculture platform. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A20.