54. Antitumor activity of polyphyl l in I with hyperthermia on human gastric cancer cell lines MKN- 45 in vitro

Objective: To evaluated the antitumor activity of PP I with hyperthermia on human gastric cancer cell lines MKN-45.
Methods: Human gastric cancer MKN-45 cells were cultured and treated with different concentration of PP I with or without hyperthermia. Cell proliferation and apoptosis were measured by MTT assay and flow cytometry. The influence of hyperthermia on the antitumor effects of PP I was measured by colony formation assay. p21 protein levels were assessed by western blot analyses.
Results: The survival rate of MKN-45 cells were significantly decreased after 24 and 48 hours culturing with different concentration of PP I , and this effect exhibited time-dose-dependent. Apoptosis rate was increased from 4.3±1.1% to 37.8±3.5% after culturing with PP I for 24 hours. Compared with PP I alone, when combined with hyperthermia, cell survival rate was decreased from 61.2±3.4% to 40.7±3.1% (P<0.05). The expression of p21 protein can be upregulated by PP I and this effect can be enhanced by hyperthermia.
Conclusions: PP I exhibits growth inhibition and apoptosis induction in human gastric cancer cell lines MKN-45, and the effects can be enhanced by hyperthermia. The antitumor mechanism may be related to upregulate the expression of p21 protein.