Abstract

Khalili A, Shahabi S, Pourfathollah AA, Ostad SN, Noori S, Mahdavi M, Shajiei A and Hassan ZM

Experimental strategies for cancer treatment have been developed to enhance cell-mediated immunity; some have generated promising results. Several heat shock proteins (HSP) derived from tumorgenic cells have been found capable of effectively initiating specific anti tumor immunity. The sympathetic nervous system innervates primary lymphoid organs and also influences T-lymphocyte maturation. This study had two main objectives: first to evaluate the effects of HSP-70-rich tumor lysate as an experimental tumor treatment and secondly, to assess whether by promoting anti-tumor cell-mediated immune responses, propranolol could improve cancer therapy outcomes. In this study, female BALB/c mice and mouse fibrosarcoma cells were used to establish a tumor model. After treatment with HSP70-rich lysate, with or without pronpranolol co-treatment, splenocyte proliferation was evaluated using ELISA BrdU kits. The ability of the treatments to shift the cytokine profile was evaluated by measuring host splenocyte IFN and IL-4 production ex vivo. The frequency of T-regulatory (Treg) cells in the spleen was analyzed using antiCD4, anti-CD25, and anti-Foxp3 triple-color immunostaining. Assessments of cytotoxic T-lymphocyte (CTL) activity and in situ tumor growth were also performed. The results showed that, compared to the untreated control group, a decrease in tumor size, IL-4 production, and levels of splenic CD4+CD25+ Foxp3+ Treg cells was observed as a result of the propranolol + HSP70 co-treatment. A significant increase in IFNγ formation was also noted. This study confirmed our hypothesis that parallel administration of HSP70-enriched lysate and propranolol could reduce tumor size in situ through increases in IFNγ and decreases in IL-4, in part via an augmentation of the host TH1-type immune response.