Integrative Analysis of Epigenetic Modulation in Melanoma Cell Response to Decitabine: Clinical Implications
Integrative Analysis of Epigenetic Modulation in Melanoma Cell Response to Decitabine: Clinical Implications
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DOI：
10.1371/journal.pone.0004563
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发表时间：
2009-02-23
期刊：
影响因子：
3.7
通讯作者：
Enghild, Jan J.
中科院分区：
文献类型：
--
作者：
Halaban, Ruth;Krauthammer, Michael;Enghild, Jan J.
地西他滨是一种表观遗传修饰剂，可以重新激活被DNA启动子甲基化抑制的基因，对一些但不是所有癌症患者有效，特别是那些患有实体瘤的患者。人们普遍认为，为了克服耐药性和改善预后，治疗应遵循肿瘤生物学，包括基因型、表观基因型和基因表达谱。因此，我们采取了一种综合方法，以更好地了解黑色素瘤细胞对临床相关剂量的地西他滨的反应，并确定联合治疗的互补靶点。我们采用了八种不同的黑色素瘤细胞株，确定了它们对增加剂量的地西他滨的生长、凋亡和DNA损伤反应，并选择了低的临床相关药物剂量进行全基因组差异基因表达、生物信息学分析和蛋白质验证研究。这些数据排除了DNA损伤反应，证明了p21（Cip 1）以不依赖于p53的方式参与，鉴定了TGF β途径基因CLU和TGFBI作为地西他滨敏感性的标志物，并揭示了对组蛋白修饰的影响，作为地西他滨诱导的基因表达的一部分。突变分析和通过siRNA的敲低涉及活化的β-连环蛋白/MITF，而不是BRAF、NRAS或PTEN突变作为抗性的来源。从结果中预测的蛋白质稳定性的重要性通过蛋白酶体抑制剂Bortezaline在增强地西他滨在其他耐药黑色素瘤细胞中的生长停滞中的协同作用来验证。我们的综合分析表明，通过对癌细胞的综合分析，确定用于患者选择和监测反应的生物标志物，以及改进联合治疗的靶点，可以实现改进的治疗。
Decitabine, an epigenetic modifier that reactivates genes otherwise suppressed by DNA promoter methylation, is effective for some, but not all cancer patients, especially those with solid tumors. It is commonly recognized that to overcome resistance and improve outcome, treatment should be guided by tumor biology, which includes genotype, epigenotype, and gene expression profile. We therefore took an integrative approach to better understand melanoma cell response to clinically relevant dose of decitabine and identify complementary targets for combined therapy. We employed eight different melanoma cell strains, determined their growth, apoptotic and DNA damage responses to increasing doses of decitabine, and chose a low, clinically relevant drug dose to perform whole-genome differential gene expression, bioinformatic analysis, and protein validation studies. The data ruled out the DNA damage response, demonstrated the involvement of p21(Cip1) in a p53-independent manner, identified the TGF beta pathway genes CLU and TGFBI as markers of sensitivity to decitabine and revealed an effect on histone modification as part of decitabine-induced gene expression. Mutation analysis and knockdown by siRNA implicated activated beta-catenin/MITF, but not BRAF, NRAS or PTEN mutations as a source for resistance. The importance of protein stability predicted from the results was validated by the synergistic effect of Bortezomib, a proteasome inhibitor, in enhancing the growth arrest of decitabine in otherwise resistant melanoma cells. Our integrative analysis show that improved therapy can be achieved by comprehensive analysis of cancer cells, identified biomarkers for patient's selection and monitoring response, as well as targets for improved combination therapy.