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黄花夹竹桃甙(Thevetoside,TS)属强心甙类药,体内、外有抗癌作用,本文对其抗肿瘤活性的机理进行了探讨。86铷示踪法显示,0.005~0.1μg/mlTS作用1h,对SMMC-7721,SGC-7901和HeLe细胞的Na+,K+-ATP酶活性有明显的抑制作用。氚标记放射性前体掺入实验显示,0.01~1.0μg/mlTS作用2h,对3H-TdR,和3H-Leu掺入K562细胞无抑制作用。NBT(四唑氮蓝)还原能力测定显示,1.0ng/mlTS作用4d,HL60细胞对NBT的还原能力达到64.2%,为对照组(19.3%)的3.3倍。RIA(放射免疫分析法)测定胞内cAMT含量较对照组细胞提高2.5倍。透射电镜观察发现,0.1ng/mlTS作用24h,细胞表现为溶解性坏死的形态学改变。提示TS通过抑制肿瘤细胞的Na+,K+-ATP酶活性,提高胞内cAMP含量而抑制肿瘤细胞的增殖并使其向正常细胞转化。
The Thevetoside (TS) is a kind of cardiotonic drug with anti-cancer effects in vivo and in vitro. The mechanism of its anti-tumor activity was discussed in this paper. The 86铷 tracer method showed that the effect of 0.005-0.1μg/ml TS for 1h significantly inhibited the Na+, K+-ATPase activity of SMMC-7721, SGC-7901 and HeLe cells. Indole-labeled radioactive precursor incorporation experiments showed that 0.01-1.0μg/ml TS treatment for 2h had no inhibitory effect on 3H-TdR and 3H-Leu incorporation into K562 cells. The determination of the reducing ability of NBT (tetrazolium blue) showed that the HL60 cells reduced the ability of NBT by 64.2% after 4 days treatment with 1.0 ng/ml TS, which was 3.3 times that of the control group (19.3%). The RIA (radioimmunoassay) assay showed that intracellular cAMT levels were 2.5-fold higher than those in the control group. Transmission electron microscopy showed that cells treated with 0.1ng/ml TS for 24h showed morphological changes of soluble necrosis. It is suggested that TS inhibits the proliferation of tumor cells and transforms them into normal cells by inhibiting Na+,K+-ATPase activity of tumor cells, increasing intracellular cAMP content.