羟基喜树碱对喉鳞癌细胞株抑制作用的研究

Inhibition of Hydroxycamptothecin on Laryngeal Squamous Carcinoma Cell Line

背景与目的:羟基喜树碱(hydroxycamptothecin,HCPT)具有较广的抗瘤谱,对多种肿瘤细胞株及移植瘤有较高的抑制率,目前尚未见HCPT在喉鳞癌治疗中的研究报告。本研究拟探讨开环和闭环HCPT对喉鳞癌细胞株(Hep-2细胞株)的抑制作用及其作用机理。方法:采用MTT法及FCM检测开环或闭环HCPT对Hep-2细胞株的体外细胞毒作用及对细胞周期的影响;观察HCPT对Hep-2细胞裸鼠移植瘤生长的影响,计算肿瘤倍增时间和抑瘤率。结果:开环或闭环HCPT对Hep-2细胞的生长抑制作用均呈浓度依赖性,其IC50分别为0.69和0.48μmol/L。高浓度的HCPT阻滞细胞周期于S期,然后诱导细胞凋亡;低浓度的HCPT轻微阻滞细胞周期于G2+M期。与对照组比较,10mg/kg开环HCPT组裸鼠移植瘤生长减慢,肿瘤倍增时间延长,两组间肿瘤体积存在显著性差异(P<0.001),其抑瘤率达77.0%;10mg/kg闭环HCPT组则因毒性大导致裸鼠死亡。结论:开环和闭环HCPT对喉鳞癌细胞具有明显的细胞毒作用,其机理与阻断细胞周期于S期以及诱导细胞凋亡有关。开环HCPT毒副作用较小,而闭环HCPT具有严重的毒副作用。

BACKGROUND ＆OBJECTIVE:Hydroxycamptothecin(HCPT) has wide antitumor spectrum and high inhibition rate of tumor cell line and xenografts. Recently,no studies on the treatment of laryngeal squamous carcinoma with HCPT were reported.Hence,this study were designed to investigate the inhibition of O HCPT [ring opened form(O HCPT)] and C HCPT[ring closed form(C HCPT)] on laryngeal squamous carcinoma cell line（Hep 2 cell line）and its mechanism. METHODS:The cytotoxicity of O HCPT and C HCPT on Hep 2 cells was measured by MTT assay and cell cycle was detected using flow cytometry (FCM). The growth state of Hep 2 cell xenografts treated with 10 mg/kg HCPT (O HCPT or C HCPT) was observed. The doubling time and the tumor inhibition rate were calculated.RESULTS:The growth inhibition of O HCPT and C HCPT on Hep 2 cell depended on concentration.The IC50 were 0 69 and 0 48 μmol/L, respectively. After treated with high concentration of HCPT, the cell cycle was arrested in S phase and then apoptosis were obviously induced. At the low concentration of HCPT, the cell cycle was slightly arrested in G2＋M phase. Compared with control group, the xenografts of O HCPT (10 mg/kg) treated group grew slowly and tumor doubling time prolonged. There was significant difference in the tumor volumes of two HCPT treated group (P< 0 001) and the tumor inhibition rate was 77 0％. All mice in C HCPT (10 mg/kg) treated group died of toxicity. CONCLUSION: The result showed that O HCPT and C HCPT had obvious cytotoxicity to laryngeal squamous carcinoma cells which mechanism was HCPT arrest cell cycle in S phase and induce cell apoptosis. O HCPT has slight toxicity effect and can be used as chemotherapeutic agent for laryngeal squamous carcinoma, but C HCPT had strong toxicity.