Low Molecular Weight From Agaricus Blazei Anti-metastatic Effect And Molecular Mechanism Study

ObjectiveTo study the effects of a kind of low molecular weight (48000) polysaccharide extracted from Agaricus Blazei (LMPAB) previously by our group on the invasiveness, angiogenesis, apoptosis, proliferation of tumor cells and immune modulation as well as expression of genes, proteins and factors related tumor metastasis so as to explore the mechanism of anti-tumor metastasis of LMPAB at molecular level.Methods1. Study on the effect of LMPAB on inhibitory tumor metastasis(1) Effect of LMPAB on invasion of Bel-7402 through reconstituted basement membrane was investigated in Transwell chambers. Bel-7402 was exposed to different concentrations (5, 10 and 20μg ? ml^-1) of LMPAB for 48h and was injected into upper chamber with Matrigel Matrix after cell counting, while the culture supernatant of NIH3T3 was injected into lower chamber. Bel-7402 in the Transwell system was incubated for 24h and migrating cells were counted under optical microscope by means of Transwell chamber'membrane HE stain.(2) Effect of LMPAB on anti-metastasis in model of artificial lung metastasis of murine melanoma B16 in C57BL/6 mice: C57BL/6 mice were injected with B16 cells through tail vein. LMPAB (50,100 and 200 mg·kg^-1·d^-1) was given respectively to model mice for 14 days. On the 15th day, the metastatic nodes on lung surface were counted by anatomical microscope.(3) Antitumor effect of LMPAB on tumor at a distant site in the double grafted tumor system: Mice were first received intradermal inoculations of S180 in both right (l×10⁶cell) and left (2×10⁵cell) flanks and then injected with LMPAB in the right tumor on the day 3,4 and 5. The tumor diameters were measured on the day 3,5,7,10,12,14,17,19 and 21 with calipers. The animals were killed on the 21st day and tumor tissue was weighed.(4) Effects of LMPAB on the formation of microvessels of chicken chorioallantoic membrane: The area of microvessels on chicken chorioallantoic membrane was measured after application of LMPAB on the CAM of chicken embryo.(5) Effect of LMPAB on Matrigel-induced angiogenesis: C57BL/6 mice were each injected subcutaneously with 0.5ml of Matrigel containing 20ng·ml⁰¹ VEGF...