Matsubara Hiroshi, Watanabe Motonobu, Imai Tsuyoshi, Yui Yoshihiro, Mizushima Yasuhiro, Hiraumi Yoshimi, Kamitsuji Yuri, Watanabe Ken-Ichiro, Nishijo Koichi, Toguchida Junya, Nakahata Tatsutoshi, Adachi Souichi
Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
J Pharmacol Exp Ther. 2009 Mar;328(3):839-48. doi: 10.1124/jpet.108.147462. Epub 2008 Dec 10.
The histone deacetylase inhibitor depsipeptide [(1S,4S,7Z,10S, 16E,21R)-7-ethylidene-4,21-bis(propan-2-yl)-2-oxa-12,13-dithia-5,8,20,23-tetraazabicyclo[8.7.6]tricos-16-ene-3,6,9,19, 22-pentone] (FK228) has attracted a great deal of interest because of its antiproliferative and apoptotic properties in various malignancies. Histone deacetylase inhibitors induce the expression of the multidrug resistance transporter P-glycoprotein (P-gp), and FK228 is a known P-gp substrate. Thus, FK228 seems to induce its own mechanism of drug resistance by up-regulating P-gp. The goal of this study was to establish human FK228-resistant osteosarcoma cell lines and to investigate whether there are mechanisms of FK228 resistance in addition to P-gp up-regulation. After 72 h in culture, the 50% inhibitory concentrations (IC(50)) of FK228 were 4.8 and 991 nM in HOS and HOS/FK8 cells, respectively, and 3.6 and 1420 nM in U2OS and U2OS/FK11 cells, respectively. Increased histone H3 acetylation was observed in FK228-resistant cell lines after a 1-h treatment with 10 nM FK228. Unlike in parental cells, significant P-gp overexpression was detected in FK228-resistant cells, and 10 nM FK228 treatment activated the mitogen-activated protein kinase (MAPK) pathway but did not induce Fas ligand (FasL) up-regulation or c-FLIP down-regulation. However, treatment of FK228-resistant cells with a combination of FK228 and mitogen-activated protein kinase kinase (MEK) inhibitors induced apoptosis, up-regulated FasL, and down-regulated c-FLIP. The expression and function of P-gp were unaltered by treatment with MEK inhibitors. These results indicate that the FK228 resistance of osteosarcoma cells is related to P-gp overexpression and MAPK pathway activation by FK228. MEK or P-gp inhibitors may be useful in overcoming this resistance.
组蛋白去乙酰化酶抑制剂缩肽(1S,4S,7Z,10S,16E,21R)-7-亚乙基-4,21-双(丙-2-基)-2-氧杂-12,13-二硫杂-5,8,20,23-四氮杂双环[8.7.6]二十三碳-16-烯-3,6,9,19,22-五酮因其在多种恶性肿瘤中的抗增殖和凋亡特性而备受关注。组蛋白去乙酰化酶抑制剂可诱导多药耐药转运蛋白P-糖蛋白(P-gp)的表达，且FK228是一种已知的P-gp底物。因此，FK228似乎通过上调P-gp来诱导其自身的耐药机制。本研究的目的是建立人FK228耐药骨肉瘤细胞系，并研究除P-gp上调外是否存在FK228耐药机制。培养72小时后，FK228在HOS和HOS/FK8细胞中的50%抑制浓度(IC50)分别为4.8和991 nM，在U2OS和U2OS/FK11细胞中分别为3.6和1420 nM。用10 nM FK228处理1小时后，在FK228耐药细胞系中观察到组蛋白H3乙酰化增加。与亲代细胞不同，在FK228耐药细胞中检测到明显的P-gp过表达，且10 nM FK228处理激活了丝裂原活化蛋白激酶(MAPK)途径，但未诱导Fas配体(FasL)上调或c-FLIP下调。然而，用FK228和丝裂原活化蛋白激酶激酶(MEK)抑制剂联合处理FK228耐药细胞可诱导凋亡，上调FasL，并下调c-FLIP。用MEK抑制剂处理对P-gp的表达和功能无影响。这些结果表明，骨肉瘤细胞对FK228的耐药性与FK228诱导的P-gp过表达和MAPK途径激活有关。MEK或P-gp抑制剂可能有助于克服这种耐药性。
