[The effects of tea polyphenols and Laminaria japonica polysaccharides on nasopharyngeal carcinoma cell HONE1 and CNE2].

Objective: To explore the effects of laminaria japonica polysaccharides(LJP) and tea polyphenols (TP) on nasopharyngeal carcinoma(NPC) cells HONE1 and CNE2, and further to explore the underlying mechanism of antitumor activity of LJP on NPC cell in vivo.

Method: To identify the logarithmic growth phase of NPC cells HONE1 and CNE2 through cell growth curve and doubling time by means of MTT, then inhibition of the cells proliferation were detected with LJP and TP separately and combined. With LJP treatment, cell apoptosis of HONE1 was examined by double staining assay. A tumor model,established by subcutaneously inoculation of NPC cell HONE1 into nude mice,was used to evaluate the inhibitory effect of LJP in vivo.

Result: Both LJP and TP had inhibition effect on two groups of cell proliferation, and LJP and TP combined effect of inhibition were higher than the two separate on two sets of experimental cell proliferation, whose effect was concentration-dependent. LJP could induce apoptosis of HONE1. With the increasing concentration of LJP, apoptosis rate increased. The apoptosis rate was(49.51 +/- 1. 89) % (P<0. 01) when treated with 320 mg/L LJP. The inhibition rate was between 50% to 60% at 72 h after treatment with 320 mg/L LJP. Compared to control group, the growth of xenografts in nude mice was significantly suppressed after administration of LJP at a dose-dependent manner. The inhibition rates were 33. 7%(P<0. 05)and 47. 0%(P<0. 01) when treated with 25.0 mg/kg and 50. O mg/kg respectively. Whereas the inhibition rate of 12.5 mg/kg group was only 16. 4%(P>0. 05).

Conclusion: LJP and TP can inhibit the proliferation of NPC cells HONE1 and CNE2 respectively,and combined use has a significant effect. LJP can inhibit the growth of NPC probably by inducing apoptosis of NPC cells in vitro and in vivo.