Previous studies indicated that the low molecular weight
polysaccharide extracts from Agaricus blazei are potential
antitumor agents or adjuvant in
tumor treatment. In this study, we investigated the antitumor activity of LMPAB, a low molecular weight
polysaccharide isolated from Agaricus blazei, and the molecular mechanisms of its antitumor activity. The antitumor effect of LMPAB was examined using mouse
sarcoma 180 (S180) xenograft models. Antiangiogenic effect of LMPAB was determined by chicken embryo chorioallantoic membrane (CAM) angiogenesis and
Matrigel-induced neovascularization in vivo models. The
mRNA and
protein levels of
vascular endothelial growth factor (
VEGF) were assessed using real-time reverse transcription-polymerase chain reaction, immunohistochemistry, and
enzyme-linked
immunosorbent assays.
Tumor inhibitory rates in the S180 xenograft models were 9.7, 23.9, and 33.0%, respectively, after administration of LMPAB at dose of 50, 100, and 200 mg/kg/day for 2 weeks. LMPAB also inhibited angiogenesis in the CAM model and
Matrigel-induced neovascularization in C57BL/6 mice. The
mRNA and
protein levels of
VEGF in
tumor tissues were significantly down-regulated in the BALB/c mice received LMPAB treatment. Furthermore, significant down-regulation of serum
VEGF levels was also observed in the mice. Our data suggest that LMPAB might be a promising agent for
tumor therapy, and the antitumor and antiangiogenic effects of LMPAB may be related with down-regulation of
VEGF.