Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
Clin Cancer Res. 2016 Apr 15;22(8):2020-31. doi: 10.1158/1078-0432.CCR-15-1435. Epub 2015 Dec 9.
Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of malignancies that despite available therapies commonly relapse. The emergence of combination epigenetic therapies in other hematologic malignancies have made investigation of such combinations in CTCL a priority. Here, we explore the synergistic antiproliferative effects of romidepsin, an HDAC inhibitor, and azacitidine, a demethylating agent, combination in CTCL.
The growth inhibition under combination treatment and single agent was explored by the MTT cell viability assay and the Annexin V/propidium iodide (PI) apoptosis assay in different CTCL cell lines and tumor cells derived from Sézary syndrome patients. Quantitative analysis of a dose-effect relationship of romidepsin and azacitidine was done by the CompuSyn software. Investigation of mechanism of action was performed by flow cytometry, immunoblotting, qRT-PCR arrays, and chromatin immunoprecipitation. Global CpG methylation sequencing was utilized to study genome methylation alteration under the treatment modalities.
The combination of romidepsin and azacitidine exerts synergistic antiproliferative effects and induction of apoptosis involving activation of the caspase cascade in CTCL cell lines and tumor cells derived from Sézary syndrome patients. We identified genes that were selectively induced by the combination treatment, such as the tumor suppressor geneRhoBthat is linked to enhanced histone acetylation at its promoter region in parallel with pronounced expression of p21. Global CpG methylation sequencing in a CTCL cell line and tumor cells demonstrated a subset of genes with a unique change in methylation profile in the combination treatment.
The synergistic antiproliferative effects of romidepsin and azacitidine combination treatment justify further exploration in clinical trials for advanced CTCL.
皮肤 T 细胞淋巴瘤（CTCL）是一组异质性恶性肿瘤，尽管有可用的治疗方法，但通常会复发。其他血液恶性肿瘤中联合表观遗传学治疗方法的出现使得在 CTCL 中研究这种联合治疗成为当务之急。在这里，我们探索了组蛋白去乙酰化酶抑制剂罗米地辛和去甲基化剂阿扎胞苷联合应用于 CTCL 的协同抗增殖作用。
通过 MTT 细胞活力测定法和 Annexin V/碘化丙啶（PI）凋亡测定法，在不同的 CTCL 细胞系和来自 Sézary 综合征患者的肿瘤细胞中探索联合治疗和单药治疗下的生长抑制作用。通过 CompuSyn 软件对罗米地辛和阿扎胞苷的剂量效应关系进行定量分析。通过流式细胞术、免疫印迹、qRT-PCR 阵列和染色质免疫沉淀研究作用机制。利用全基因组 CpG 甲基化测序来研究治疗方式下的基因组甲基化改变。
罗米地辛和阿扎胞苷联合应用对 CTCL 细胞系和来自 Sézary 综合征患者的肿瘤细胞具有协同的抗增殖作用，并诱导细胞凋亡，涉及半胱天冬酶级联的激活。我们鉴定了一些被联合治疗选择性诱导的基因，如肿瘤抑制基因 RhoB，其与启动子区域的组蛋白乙酰化增强相关，同时伴有 p21 的显著表达。在 CTCL 细胞系和肿瘤细胞中的全基因组 CpG 甲基化测序显示，联合治疗在一组基因中具有独特的甲基化谱变化。
罗米地辛和阿扎胞苷联合治疗的协同抗增殖作用证明了其在晚期 CTCL 临床试验中进一步探索的合理性。
