Department of Pathology, College of Medicine, National Taiwan University, National Taiwan University Hospital, Taipei, Taiwan.
Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
J Mol Med (Berl). 2018 Dec;96(12):1307-1318. doi: 10.1007/s00109-018-1697-7. Epub 2018 Oct 4.
In this study, we aimed to investigate the antitumor effects of trichostatin A (TSA), an antifungal antibiotic that inhibits histone deacetylase (HDAC) family of enzymes, alone or in combination with anyone of the three chemotherapeutic agents (cisplatin, gemcitabine, and doxorubicin) for the treatment of human urothelial carcinoma (UC). Two high-grade human UC cell lines (T24 and NTUB1) were used. Cytotoxicity and apoptosis were assessed by MTT assay and flow cytometry, respectively. The expression of phospho-c-Raf, phospho-MEK1/2, and phospho-ERK1/2 was measured by western blotting. ERK siRNA knockdown and the specific MEK inhibitor U0126 were used to examine the role of Raf/MEK/ERK signaling pathway in combined cytotoxicity of TSA and chemotherapy. TSA co-treatment with any one of the three chemotherapeutic agents induced synergistic cytotoxicity (combination index < 1) and concomitantly suppressed chemotherapeutic drug-induced activation of Raf-MEK-ERK pathway. Combination of ERK siRNA knockdown and treatment with the specific MEK inhibitor (U0126) enhanced the cytotoxic effects of the chemotherapy on UC cells. These observations were confirmed in a xenograft nude mouse model. Moreover, activated Raf/MEK/ERK pathway was observed in human bladder UC specimens from patients with chemoresistant status. In conclusion, TSA elicits a synergistic cytotoxic response in combination with chemotherapy via targeting the Raf/MEK/ERK pathway. TSA elicits synergistic cytotoxic response in combination with three DNA-damaging drugs (cisplatin, gemcitabine, and doxorubicin). Activated Raf/MEK/ERK pathway is involved in chemoresistant mechanism of UC. Combining chemotherapeutic agents with HDAC inhibitor (TSA) or with targeting Raf/MEK/ERK pathway is promising to circumvent chemoresistance in UCs.
在这项研究中，我们旨在研究曲古抑菌素 A（TSA）的抗肿瘤作用，TSA 是一种抑制组蛋白去乙酰化酶（HDAC）家族酶的抗真菌抗生素，单独或与三种化疗药物（顺铂、吉西他滨和阿霉素）中的任何一种联合用于治疗人尿路上皮癌（UC）。使用了两种高级别人 UC 细胞系（T24 和 NTUB1）。通过 MTT 测定法和流式细胞术分别评估细胞毒性和细胞凋亡。通过 Western blot 测定磷酸化 c-Raf、磷酸化 MEK1/2 和磷酸化 ERK1/2 的表达。使用 ERK siRNA 敲低和特异性 MEK 抑制剂 U0126 来研究 Raf/MEK/ERK 信号通路在 TSA 和化疗联合细胞毒性中的作用。TSA 与三种化疗药物中的任何一种联合治疗均诱导协同细胞毒性（组合指数<1），并同时抑制化疗药物诱导的 Raf-MEK-ERK 通路激活。ERK siRNA 敲低与特异性 MEK 抑制剂（U0126）联合治疗增强了化疗药物对 UC 细胞的细胞毒性作用。这些观察结果在异种移植裸鼠模型中得到了证实。此外，在具有化疗耐药状态的患者的人膀胱癌 UC 标本中观察到激活的 Raf/MEK/ERK 通路。总之，TSA 通过靶向 Raf/MEK/ERK 通路与化疗联合产生协同细胞毒性反应。TSA 与三种 DNA 损伤药物（顺铂、吉西他滨和阿霉素）联合产生协同细胞毒性反应。激活的 Raf/MEK/ERK 通路参与 UC 的化疗耐药机制。将化疗药物与 HDAC 抑制剂（TSA）或与靶向 Raf/MEK/ERK 通路联合使用有望规避 UC 中的化疗耐药性。
