Immunomodulatory effects of β-defensin 2 on tumor-associated macrophages induced antitumor function in breast cancer

Background: TAMs express cytokines and chemokines that can suppress antitumor immunity and promote tumor progression. The immunomodulatory and antitumor function of β-defensin 2 is still unclear, despite the evidence of infection response. So, this study aims to investigate the association between β-defensin 2 and TAMs and determine the role in tumor-promoting attributes of TAMs reversal of phenotype in tumor regression. Methods: : Swiss albino mice and C127i breast cancer cell line were used in this study. C127i conditioned media was prepared and generated macrophage-derived TAM to study antitumor function. Flow cytometry was performed for phenotype identification of macrophages and TAMs. MTT was performed to estimate cytotoxicity and dose optimization of β-defensin 2. Oxidative stress was analyzed by H 2 O 2 and NO estimation, and qPCR was performed for iNOS, cytokines and chemokines quantification. Results: : PEC harvested macrophages were characterized by flow-cytometry using F4/80, CD11c antibodies with 98% pure population of macrophages and cultured in C127i conditioned media for 7 days. TAM markers were estimated, and it was found that 98 % expression of F4/80, CD-206, and CD-115 expression compared to macrophages. Purified 100ng/ml of β-defensin 2 was used to stimulate the TAMs 98% population was viable, which was confirmed by cell viability assay. ROS levels decreased (TAMs alone p<0.05, TAMs treated p<0.001) compared to control. IL-6, IL-10, IL-3, TNF-α, and TGF-β and CXCL-1, CXCL-5, CXCL-15, CCL-24, and CCL-5 decreased drastically compared to control. Conclusion: This is the first report of β-defensin 2 on TAMs to elucidate the immunomodulatory and anti-tumor function. It was found that the cytokines and chemokines molecules, ROS expression, pliably changed, which facilitates tumor regression. β-defensin 2 is a new therapeutic target peptide to revert tumor-promoting function.