Ganoderma atrum polysaccharide evokes antitumor activity via cAMP-PKA mediated apoptotic pathway and down-regulation of Ca(2+)/PKC signal pathway.

Ganoderma atrum polysaccharide (PSG-1) has been commonly suggested as a candidate for prevention and therapy of cancer. We investigated the antitumor effect and the underlying molecular mechanisms of PSG-1. The results showed that PSG-1 inhibited tumor growth and resulted in tumor cell apoptosis in vivo. Here, the data revealed that PSG-1 caused a markedly increase in cAMP and PKA activities, rather than cGMP and PKC. Moreover, the treatment of PSG-1 induced a dramatic increase in the protein level of PKA. In contrast, the expression of PKC and intracellular [Ca(2+)]i were inhibited. Our study also revealed that treatment with PSG-1 increased the spleen and thymus weights, lymphocyte proliferation and macrophage phagocytic activity in tumor-bearing mice. Taken together, we conclude that PSG-1 could inhibit the tumor growth, possibly in part by enhancing the induction of apoptosis through cAMP-PKA signaling pathway and down-regulation of Ca(2+)/PKC signal pathway, activating host immune function in S180-bearing mice.

Zhang S ，Nie S ，Huang D ，Huang J ，Feng Y ，Xie M ... -  《-》

A polysaccharide from Ganoderma atrum inhibits tumor growth by induction of apoptosis and activation of immune response in CT26-bearing mice.

Zhang S ，Nie S ，Huang D ，Huang J ，Feng Y ，Xie M ... -  《-》

A novel polysaccharide from Ganoderma atrum exerts antitumor activity by activating mitochondria-mediated apoptotic pathway and boosting the immune system.

Zhang S ，Nie S ，Huang D ，Feng Y ，Xie M ... -  《-》

Ganoderma atrum polysaccharide induces anti-tumor activity via the mitochondrial apoptotic pathway related to activation of host immune response.

Ganoderma atrum polysaccharide (PSG-1), the major active ingredient isolated from Ganoderma atrum, has been suggested as a candidate for cancer therapy. The aim of this study was to investigate the anti-tumor effect of PSG-1 using sarcoma 180 (S-180) transplanted mice and further to examine the molecular mechanisms of PSG-1-induced anti-tumor effect. Results showed that PSG-1 significantly inhibited tumor growth in S-180-bearing mice. PSG-1-induced tumor apoptosis was associated with the alteration of Bcl-2 family proteins, increase of reactive oxygen species generation, loss of mitochondrial membrane potential (Δψ(m) ), release of cytochrome c from the mitochondria into cytosol, and activation of caspase-3 and -9. Elevation of immune function was also shown during PSG-1-induced tumor apoptosis, as evidenced by increase of spleen and thymus indexes, lymphocyte proliferation, concentrations of tumor necrosis factor (TNF)-α, and interleukin-2 in serum. Furthermore, the combined treatment of PSG-1 and cyclophosphamide (CTX) results in an enhancement of the anti-tumor effect of CTX alone via increased host immune response. These results suggested that PSG-1 had a potent anti-tumor activity by induction of tumor apoptosis through mitochondrial pathways, and immunoenhancement effect of PSG-1 was related to its anti-tumor effect. In addition, PSG-1 enhanced CTX-induced anti-tumor activity in S-180-bearing mice.

Li WJ ，Chen Y ，Nie SP ，Xie MY ，He M ，Zhang SS ，Zhu KX ... -  《-》

Signaling pathway involved in the immunomodulatory effect of Ganoderma atrum polysaccharide in spleen lymphocytes.

Yu Q ，Nie SP ，Wang JQ ，Huang DF ，Li WJ ，Xie MY ... -  《-》