新型组蛋白去乙酰化酶抑制剂FK228对人结肠癌细胞HCT-116的体内外抑制作用

Inhibitory effect of a novel histone deacetylases inhibitor FK228 on human colon cancer HCT-116 cells in vitro and in vivo

目的探讨新型组蛋白去乙酰化酶抑制剂FK228对人结肠癌细胞HCT-116的体内外抑制作用。方法采用不同浓度的FK228和氟尿嘧啶（5-Fu）处理HCT-116细胞24、48、72h，采用CCK．8法观察比较FK228对结肠癌HCT-116细胞的生长抑制作用。体内实验构建BALB／c裸鼠皮下移植瘤模型，腹腔注射FK228（5mg／kg）和5-Fu（50mg／kg），比较FK228对HCT-116裸鼠移植瘤的生长抑制作用及血液、肝、。肾毒性。结果FK228对结肠癌细胞HCT-116具有明显的生长抑制作用，且具有时间和剂量依赖性，其48h的IC50为12．05ng／ml，而5-Fu的IC50仅为18．92μg/ml。给药20d后，FK228组裸鼠肿瘤体积为（139．71±44．54）mm^3，显著低于5-Fu组[（282．28±58．81）mm^3，P〈0．01]和模型组[（520．65±39．73）mm^3，P〈0．01]；FK228组裸鼠肿瘤重量为（0．07±0．02）g，显著低于5-Fu组[（0．20±0．08）g，P〈0．01]。5-Fu组和FK228组的肿瘤抑制率分别为45．8％和73．2％（P〈0．01）。5-Fu组和FK228组的丙氨酸转氨酶（ALT）水平显著高于模型组和空白组（均P〈0．01），而FK228组的血尿素氮（BUN）水平与空白组、模型组的差异无统计学意义（均P〉0．05），5-Fu组的BUN水平明显高于模型组和空白组（均P〈0．01）。5-Fu组裸鼠的白细胞（WBC）、红细胞（RBC）、血红蛋白（Hb）和血小板（PLT）水平显著低于模型组（均P〈0．05），而FK228组裸鼠仅WBC水平与模型组差异有统计学意义（P〈0．05）。HE染色结果显示，FK228组肝细胞局部出现纤维变性，并伴有血细胞和炎性细胞浸润；肾脏出现了轻微肾小管水肿，其他形态正常。5-Fu组肝细胞出现了局部大量坏死、变形，一部分肝细胞水肿变形；肾脏出现了明显的肾小球和肾小管变形、坏死，管壁变薄。结论与5-Fu比较，FK228可在体内外明显抑制HCT-116细胞的生长，对肾和血液系统的毒性不明显，具有较大的研究意义和临床价值。

Objective To investigate the inhibitory effects of a novel histone deacetylases inhibitor FK228 on human colon cancer HCT-116 cells in vitro and in vivo, and evaluate its toxicity and side effects. Methods The in vitro growth inhibitions of HCT-116 cells by different concentrations of FK228 and 5-Fu for 24, 48 and 72 h were assessed by CCK-8 assay. BALB/c nude mouse models of tumor xenografts were prepared by subcutaneous implantation of tumor tissue, and 4 mg/kg FK228 and 50 mg/kg 5-Fu were i. p. injected, respectively. The inhibitory effects on tumor growth, hematology, and liver and kidney function were evaluated. Results CCK-8 assay indicated that FK228 had an obvious growth inhibitory effect on HCT-116 cells in a doseand time-dependent manner. The ICs0 of FK228 in HCT-116 cells was 12.05 ng/ml for 48 h, while the ICs0 of 5-Fu was 18.92 μg/ml. At 20 days after FK228 and 5-Fu treatment, the tumor volume of the FK228 group was （ 139.71 ±44.54） mm3 , significantly lower than that of the 5-Fu group [ （282.28 ± 58.81 ） mm3 ] and that of the model group [ （520.65 ± 39.73 ） mm3, P 〈 0.01 for both ]. The average tumor weight was （0.07 ± 0.02 ） g in the FK228 group, significantly lower than that of the 5-Fu group [（0.20 ± 0. 08） g, P 〈 0. 01 ]. The tumor growth inhibition rate of the FK228 group was 73.2%,significantly higher than that of the 5-Fu group （45.8%, P 〈0.01 ）. The ALT levels of the FK228 and 5- Fu groups were significantly higher than that of the model group （ P 〈 0.01 ）. The BUN of 5-Fu group was significantly higher than that of the model group （ P 〈 0. 01 ）, but the BUN of FK228 group was not significantly different from that of the blank and control groups （ P 〉 0.05 for both）. Routine blood test showed that WBC, RBC, Hb and PLT of the 5-Fu group were significantly lower than those of the model group （P 〈0.05 for all）, but only WBC of the FK228 group was significantly lower than that of the model group （ P 〈 0.05 ）. The pathological examination using HE staining revealed that in the FK228 group, there were fibrosis and inflammatory cell infiltration in the liver tissue, and mild edema of the renal tubules in the kidney. However, in the 5-Fu group there were extensive hepatocyte edema and necrosis in the liver, and evident deformation and necrosis of glomeruli and tubules, and tubular wall thinning in the kidney. Conclusions The results of this study indicate that FK228 can more effectively than 5-Fu inhibit the growth of HCT-116 cells in vitro and vivo, and without obvious toxic effect on the kidney and hematology. Its clinical value in colon cancer treatment deserves further investigation.