MAPK抑制剂与组蛋白去乙酰化酶抑制剂对甲状腺癌细胞的联合再分化作用

Combined redifferentiation via HDAC inhibitor and MAPK inhibitor in thyroid cancer cells

背景与目的:应用MAPK抑制剂诱导再分化是治疗放射性碘难治性甲状腺癌的一种全新策略,但其临床有效率偏低。组蛋白去乙酰化酶抑制剂(histone deacetylase inhibitor,HDACI)是另一类诱导甲状腺癌再分化的药物,将其与MAPK抑制剂联合有可能提高再分化疗效。本研究旨在评估MAPK与HDACI联用是否能提高再分化的效果。方法:采用实时荧光定量聚合酶链反应(real-time fluorescent quantitative polymerase chain reaction,RTFQ-PCR)、蛋白[质]印迹法(Western blot)、免疫荧光、流式细胞术、放射性核素摄取/流出及克隆形成等实验方法测试BRAF/MEK抑制剂(达拉非尼/司美替尼)及去乙酰化酶抑制剂(帕比司他)单药和联合用药时3种甲状腺癌细胞(BCPAP、K1和BHP 2-7)的碘和糖代谢相关基因的表达水平和功能状态。结果:达拉非尼/司美替尼可以一定程度提高BCPAP和K1细胞中碘代谢相关基因表达并抑制葡萄糖转运体表达;帕比司他对3种细胞都有一定的再分化作用。达拉非尼/司美替尼与帕比司他联合作用在BCPAP和K1细胞中取得较单药更好的再分化效果,在BHP 2-7中并未获得比单用帕比司他更明显的效果。结论:对具有BRAFV600E突变的甲状腺癌细胞应用达拉非尼/司美替尼和帕比司他联合用药,可以获得较单药更好的再分化效果。

Background and purpose： Redifferentiation therapy with MAPK inhibitor is a novel strategy for radioiodine-refractory differentiated thyroid cancer, but its efficacy is relatively low. Histone deacetylase inhibitor （HDACI） is another kind of redifferetiation drug, given histone deacetylation at the sodium/iodide symporter （NIS） promoter by histone deacetylase （HDAC） as a mechanism, combined therapy using HDACI and BRAF/MEK inhibitor may produce better effect. In the present study, we assessed whether combining HDACI with BRAF/MEK inhibitor suppressing both BRAF/MEK and HDAC could more effectively induce thyroid gene expression and radioiodine uptake in thyroid cancer cells. Methods： We tested iodine and glucose handling gene expression and radioiodine uptake in BCPAP, K1, BHP 2-7 cells treated with dabrafenib/selumetinib and panobinostat alone or in combination using （real-time fluorescent quantitative polymerase chain reaction （RTFQ-PCR）, Western blot, immunofluorescence, flow cytometry, radionuclide uptake/efflux assay and in vitro clonogenic assay. Results： Dabrafenib/selumetinib induced modest expression of thyroid genes and radioiodine uptake and suppressed GLUT1 expression in BCPAP and K1 cells, panobinostat showed redifferetiation effect in all the cells. Dabrafenib/selumetinib and panobinostat showed synergistic effect on redifferentiation in BCPAP and K1 cells. Conclusion： Simultaneously suppressing BRAF/MEK and HDAC induced more robust expression of thyroid genes and radioiodine uptake in thyroid cancer cells harboring BRAFV600E compared with suppressing BRAF/MEK or HDAC alone, which warrants further investigation in animal and clinical trials.