BRD-glucan exhibits potent immunochemotherapeutic activity in vitro and in vivo

Abstract

We carried out in vitro and in vivo assays to investigate the immunomodulatory and immunochemotherapeutic action mechanism of BRD-glucan, a high molecular weight ( approximately 3,500 kDa) polysaccharide isolated from Aureobasidium sp, and assessed the efficacy of BRD-glucan/adriamycin co-treatment of animal cancer models. RT-PCR and suspension hemolytic, plaque forming, wounding, invasion and cell proliferation assays were utilized to investigate the in vitro immunochemotherapeutic effects of BRD-glucan. In vivo, the effects of BRD-glucan and BRD-glucan/adriamycin co-treatment were tested in a B16 melanoma initiation model and in C57BL/6 mice. In vitro, BRD-glucan did not affect the cellular wounding response or invasion activity; treatment with BRD-glucan led to increase proliferation of B cells, natural killer cells and macrophages, but not T cells. In addition, we found that the BRD-glucan activation of B cells and macrophages was dependent on Toll-like receptor2 (TLR2) and TLR4, which play important roles in innate and adaptive immunity. In vivo, BRD-glucan/adriamycin co-treatment effectively reduced the number and size of metastatic colonies. Based on the results of our in vitro and in vivo toxicity, safety and immunochemotherapy assays, we propose that BRD-glucan is a promising immunochemotherapeutic anti-tumor agent.