Enhancement of Cyclophosphamide-induced Antitumor Effect by a Novel Polysaccharide from Ganoderma Atrum in Sarcoma 180-bearing Mice

The aim of this study was to investigate the enhancement of Ganoderma atrum polysaccharide (PSG-1) on cyclophosphamide (CTX)-induced antitumor effect in sarcoma 180 (S-180)-bearing mice. Results showed that both CTX and PSG-1 delayed tumor growth and resulted in tumor apoptosis. The combined regimen was superior to either modality alone. Moreover, the combined treatment-induced apoptosis was mediated via mitochondrial pathway, as evidenced by alterations of Bcl-2 family proteins, loss of mitochondrial membrane potential (Δψ(m)), cytochrome c release, and caspases activation. Our results also showed that thymus and spleen indexes, lymphocytes proliferation, and concentrations of cytokine in the CTX group were decreased, which were alleviated by PSG-1. Additionally, the combined treatment ameliorated oxidative stress as compared with CTX alone. Taken together, we conclude that PSG-1 improved the antitumor effect of CTX, possibly in part mediated by enhancing the induction of apoptosis via mitochondrial pathways, activating host immune function, and modifying the redox system in S-180-bearing mice.