异搏定与它莫西芬联合逆转高三尖杉酯碱耐药的体外研究

目的：降低逆转剂的毒副作用，提高耐药的逆转效果。方法：用异搏定（ＶＥＲ）和它莫西芬（ＴＡＭ）单独或联合体外逆转高三尖杉酯碱（ＨＨＴ）耐药，药敏试验采用半固体琼脂集落培养法。结果：ＶＥＲ和ＴＡＭ单独或联合均不能增强ＨＨＴ对Ｋ５６２敏感细胞的杀伤；而在ＨＨＴ耐药细胞株（Ｋ５６２／Ｈ２０）中，无细胞毒性剂量４μｍｏｌ／Ｌ和８μｍｏｌ／Ｌ的ＶＥＲ或ＴＡＭ均能明显逆转Ｋ５６２／Ｈ２０细胞对ＨＨＴ的耐药，ＩＣ５０由４４６．８±０．０８μｇ／Ｌ分别下降为４５．１±０．０２，２２．４±０．０３或８５．１±０．０３，２６．４±０．０２μｇ／Ｌ。采用临床可达到血药浓度的２μｍｏｌ／ＬＶＥＲ与４和８μｍｏｌ／ＬＴＡＭ联合，耐药细胞的ＩＣ５０分别降为３０．４±０．０２和４．３±０．０４μｇ／Ｌ，后者的ＩＣ５０与敏感株相近。以恒定浓度比ＶＥＲ与ＴＡＭ联合（１∶４）逆转ＨＨＴ耐药，联合指数值均＜１，有明显的协同作用。结论：单独使用ＶＥＲ或ＴＡＭ仅能部分逆转耐药，两者联合有明显的协同作用。

In vitro reversal of homoharringtonine resistance by the combination of tamoxifen and verapamil

OBJECTIVE: To investigate the reversal of homoharringtonine (HHT)-resistance by tamoxifen (TAM) or verapamil (VER) alone or in combination. METHODS: The drug-sensitivity test was performed with semisolid agar culture. RESULTS: The cytotoxicity of HHT to K562/S cells was not enhanced by TAM or VER alone or in combination,but HHT resistance in HHT resistant cells (K562/H20) was reversed by VER and TAM at nontoxic doses (4micromol/L or 8micromol/L). The IC50 of K562/H20 for HHT decreased from 446.8 +/- 0.08microg/L to 45.1 +/- 0.02microg/L in the presence of 4micromol/L of VER, to 22.4 +/- 0.03microg/L in 8micromol/L of VER, to 85.1 +/- 0.03microg/L in 4micromol/L of TAM and to 26.4 +/- 0.02microg/L in 8micromol/L of TAM. In the presence of combinations of 2micromol/L VER and 4micromol/L TAM and of 2micromol/L VER and 8micromol/L TAM, IC50 of K562/H20 decreased to 30.4 +/- 0.02microg/L and 4.3 +/- 0.04microg/L, respectively. CONCLUSION: HHT-resistance could be reversed by VER or TAM alone, and the combination of the two drugs showed a synergistic effect.