Tumor-associated macrophages facilitate bladder cancer progression by increasing cell growth, migration, invasion and cytokine expression

Background/Aim: Interactions between stromal and tumor cells in tumor microenvironment contribute to tumor progression. In bladder cancer (BCa), infiltration of macrophages in tumors correlates with cancer progression. Herein, the aim was to study the paracrine effects of tumorassociated macrophages (TAM) on BCa cells. Materials and Methods: The correlation between TAMs and tumor grade and stages was examined in tumor tissue microarrays. In addition, a conditioned media (CM) model was employed to investigate the paracrine effects of macrophages on BCa cell growth, migration, and invasion, as well as on the cytokine profile of each cell line. Results: The correlation of tumorinfiltrating macrophages with high-grade and muscleinvasive BCa was demonstrated in human bladder tumor tissue microarrays. CM from co-cultures of macrophages and BCa cells increased BCa cell growth, migration and invasion. Moreover, higher mRNA and protein expression levels of CCL5 and IL-8 were found in cells and CM from co-cultures, respectively. Conclusion: The paracrine interaction between BCa cells and TAMs led to enhanced BCa cell growth, migration, and invasiveness, and moreover, increased IL-8 and CCL5 cytokine production in tumor microenvironment.