Therapeutic targeting of tumor-associated macrophages through microscale engineering of the prostate cancer microenvironment.

Abstract

184 Background: The tumor microenvironment (TME) plays integral roles in prostate cancer progression and is a high value therapeutic target. The development of effective TME-targeted therapies is limited by current technologies which are insufficient to replicate or analyze this complex environment. To address these challenges, we have developed a microfluidic cell culture platform known as STACKS, which permits co-culture of up to 6 patient-derived cell populations as well as compartmentalized, multiplexed analysis of gene expression, cell signaling, and matrix remodeling. We have focused on investigation of tumor-associated macrophages (TAMs), which have been implicated in prostate cancer growth, metastasis, survival, and therapeutic resistance. Methods: Using blood and prostate tissue obtained through biomarker studies at the University of Wisconsin, we isolated patient-derived cell populations for culture and analysis within the STACKS device. Monocytes obtained from peripheral blood were differentiated into tumor inhibitory (M1) and tumor promoting (M2) macrophages in the device. RNA, protein, and secretory factor expression were analyzed following manipulations of culture surface, cytokine exposure, and multi-cell culture with tumor and stromal cell populations. Results: We report that physical properties of the TME, such as topography and hydrophilicity, impact expression of tumor-promoting genes within macrophages. We also characterized macrophage expression of pro- and antitumor genes, including CCL18, CXCL10, CXCL11, IL-10, IL-12b, VEGF, and identified expression profiles that are dependent on tumor and stromal cell populations in co-culture and diverge from classical M1/M2 characterization. Conclusions: The STACKS platform is capable of advanced modeling and analysis of the prostate cancer TME. Investigation of patient-derived monocytes within STACKS has identified physical properties of the TME that affect tumor-related functions of macrophages and has also demonstrated that an M1/M2 classification spectrum may not be sufficient for characterizing TAMs. These findings represent new therapeutic targets for prostate cancer treatment.