Effect of Y1Bcy1p overexpression on structural characteristics and antitumor activity of polysaccharides from Chaetomium globosum CGMCC 6882.

The Y1Bcy1p gene-amplified strain Chaetomium globosum CGMCC 6882 Y1Bcy1p OE was structured with Agrobacterium tumefaciens GV3101 mediation. Growth performances revealed that C. globosum CGMCC 6882 Y1Bcy1p OE had shorter mycelia, increased density, and smaller and looser mycelium particles compared with the wild-strain C. globosum CGMCC 6882. C. globosum CGMCC 6882 (CGP) and C. globosum CGMCC 6882 Y1Bcy1p OE (CGP-OE) had polysaccharides yields of 2.16 ± 0.37 and 5.88 ± 0.51 g/L, respectively. Structural analysis indicated that CGP was composed of glucose, mannose, galactose, and galacturonic acid, at a molar ratio of 81.87:10.85:5.37:1.91. However, CGP-OE comprised glucose, mannose, galactose, arabinose, and fucose, at a molar ratio of 50.41:28.44:20.58:0.53:0.04. Meanwhile, CGP-OE had lower molecular weight (3.771 kDa) and higher homogeneity (1.54) than CGP (51.975 kDa and 1.94, respectively). In vitro antitumor activity of CGP-OE against MDA-MB-231 cells, which occurred via blocking of tumor cells in the S phase, was approximately 500-fold that of CGP. With intervention via tail-vein injection, CGP-OE increased the body weight of tumor mice and reduced tumor volume. Furthermore, CGP-OE and CGP significantly decreased the weights of lung and spleen in tumor mice, with the former exerting preferred effects.