組織蛋白去乙醯酶抑制劑誘發CD1d表現之研究

Abstract

本論文探討新穎抗癌藥物，HDAC抑制劑引發CD1d表現與其免疫調節之功能。在A549和TC-1細胞，TSA和SAHA引發dose-及time-dependent之CD1d表現，進一步探討TSA誘導CD1d mRNA表現之機轉，A549及TC-1細胞預先處理PKC抑制劑Ro318220、ROCK抑制劑Y27632、CaM kinase II抑制劑KN-62、p38抑制劑SB203580、MEK抑制劑PD98059、JNK抑制劑SP600125、PI3K抑制劑LY294002、mTOR抑制劑rapamycin、Akt抑制劑SH-5或PI3K抑制劑wortmannin，皆不影響TSA所誘導之CD1d mRNA表現。Sp1抑制劑MTM可阻斷SAHA所誘導的CD1d mRNA表現及Sp1 luciferase和RARE3-tk-luciferase reporter活性。將GAL4-Sp1及Fc-luciferase reporter同時transfect至A549細胞，發現HDAC抑制劑是經由增加Sp1 transactivation活性促進Sp1之reporter活性。ChIP實驗證明，HDAC抑制劑會增加Sp1與乙醯化histone-H3結合至CD1d啟動子。將TC-1細胞與C57BL/6小鼠之脾臟細胞共同培養，HDAC抑制劑所誘導表現之CD1d蛋白，可呈現glycolipid給NKT細胞，使之活化增加IFN-γ釋放，但降低IL-4之釋放。DNMT抑制劑會促進HDAC抑制劑增加CD1d之mRNA與蛋白表現；HDAC6抑制劑tubacin不影響CD1d之mRNA，但增加膜上蛋白之表現。

We investigate the effect of novel anticancer drugs, HDAC inhibitors on CD1d expression in tumor cells, and the related immune regulation. TSA and SAHA were found to induce CD1d expression in a dose- and time-dependent manner in A549 ( human lung adenocarcinoma cell line) and TC-1 ( mouse lung cancer cell line) cells. TSA-induced CD1d was not blocked by the pre-treatment with PKC inhibitor (Ro318220)、ROCK inhibitor (Y27632)、CaM kinase II inhibitor (KN-62)、p38 inhibitor (SB203580)、MEK inhibitor PD98059、JNK inhibitor (SP600125)、PI3K inhibitor (LY294002)、mTOR inhibitor (rapamycin)、Akt inhibitor (SH-5) or PI3K inhibitor (wortmannin). However, Sp1 inhibitor MTM blocked the CD1d mRNA expression, Sp1 luciferase and RARE3-tk-luciferase reporter activity induced by SAHA. Co-transfection of GAL4-Sp1 and Fc-luciferase reporter demonstrated that HDAC inhibitor induced Sp1 luciferase reporter activity by enhancing Sp1 transactivation activity. The binding of Sp1 and acetylated histone-H3 to CD1d promoter was increased by HDAC inhibitors. Co-culture of C57BL/6 splenocytes with SAHA-treated TC-1 cells showed the presentation of glycolipid to the splenocytes, resulting in the increased secretion of IFN-γ and decreased secretion of IL-4. DNMT inhibitor, Zebularine promoted the CD1d induction by HDAC inhibitor. HDAC6 inhibitor, tubacin induced CD1d protein but not mRNA expression. In summary, these results indicate that HDAC inhibitors could up-regulate CD1d expression in tumor cells, and tumor/glycolipid are effective for IFN-γ secretion by splenocytes to exert possible anti-tumor activity.