Effects of sulfated polysaccharide from Masson pine (Pinus massoniana) pollen on the proliferation and cell cycle of HepG2 cells

AimTo explore the inhibitory effect of sulfated polysaccharide from Masson pine (Pinus massoniana) pollen (SPPM60) on G2/M phase of human liver cancer HepG2 cells and its mechanism.MethodsThe proliferation rate of HepG2 cells was evaluated by methyl thiazolyl tetrazolium (MTT) colorimetric assay. The cycles of HepG2 cells were measured by flow cytometry when 200 μg/ml concentration of SPPM60 was adopted, the expression of the genes related to cell cycle was detected by real-time PCR.ResultsSPPM60 inhibited the proliferation of HepG2 cells and the inhibition rate was elevated with increase of SPPM60 concentration. After treatment with 200 μg/ml of SPPM60, the percentage of S phase cells was decreased, but that of G2/M phase was significantly increased (72 h vs control: 32.96 ± 0.33% vs 18.59 ± 0.04%, 3.44 ± 0.05% vs 18.30 ± 0.08%, P < 0.01). The results of real-time PCR showed that SPPM60 could down-regulate the mRNA levels of CDK1 and CyclinB (P < 0.01), and up-regulate the expression of p53 and p21 (P < 0.05).ConclusionSPPM60 causes arrest of HepG2 cells at G2/M phase, and the mechanism is related to the down-regulation of CDK1 and CyclinB and up-regulation of p53 and p21 expression.