A personalized medicine approach identifies enasidenib as an efficient treatment for IDH2 mutant chondrosarcoma [MethArray_5days]

The heterogenous genomic nature of most sarcoma subtypes makes them especially indicated for personalized treatment approaches. Here, we developed a personalized medicine strategy based in the use of patient-derived cell lines as a drug-testing platform. Targeted sequencing of a panel of cancer-related genes in these models revealed the presence of IDH1 and IDH2 mutations in two chondrosarcomas. Mutant IDH (mIDH) enzymes produce the oncometabolite 2-HG which contributes to driving tumor growth. Thus, we treated several chondrosarcoma models with specific mIDH1/2 inhibitors. Among these treatments, only the mIDH2 inhibitor enasidenib was able to decrease 2-HG levels and to efficiently reduce the viability of mIDH2 chondrosarcoma cells. Importantly, oral administration of enasidenib in xenografted mice resulted in a complete abrogation of tumor growth. Enasidenib induced a profound remodeling of the transcriptomic landscape not associated to changes in the 5mC methylation levels and its anti-tumor effects were associated to the repression of proliferative pathways such as those controlled by E2F factors. Overall, this work provides the first preclinical evidence for the use of enasidenib to treat mIDH2 chondrosarcomas. To investigate the effect of enasidenib in the methylation, we treated IDH2 mutated chondrosarcoma primary cell line for 120 h with the inhibitor (20 μM) and with the vehicle DMSO (control). The EZ-96 DNA Methylation Kit (Zymo Research) was used to perform the bisulphite conversion. The processed DNA samples were then hybridised to Infinium MethylationEPIC v2.0 BeadChip following the Illumina Infinium HD Methylation Assay protocol.

多数肉瘤亚型具有基因组异质性的特征，这使其尤其适合采用个性化治疗策略。本研究开发了一种以患者来源细胞系作为药物筛选平台的个性化医疗策略。对这些模型中的癌症相关基因组合进行靶向测序后，在两例软骨肉瘤样本中检测到了IDH1和IDH2突变。突变型IDH（mutant IDH, mIDH）酶可产生致癌代谢物2-HG，进而促进肿瘤生长。因此，我们使用特异性mIDH1/2抑制剂处理了多株软骨肉瘤模型。在上述抑制剂中，仅mIDH2抑制剂恩西地平（enasidenib）能够降低2-HG水平，并有效降低mIDH2型软骨肉瘤细胞的活力。值得注意的是，对异种移植瘤小鼠口服恩西地平，可完全阻断肿瘤生长。恩西地平可引发转录组图谱的显著重塑，且该重塑与5-甲基胞嘧啶（5mC）甲基化水平的变化无关；其抗肿瘤效应与增殖通路的抑制相关，例如受E2F因子调控的通路。综上，本研究首次提供了恩西地平用于治疗mIDH2型软骨肉瘤的临床前证据。为探究恩西地平对甲基化的影响，我们使用20 μM的恩西地平及溶媒二甲基亚砜（DMSO，对照组）处理IDH2突变型软骨肉瘤原代细胞系120小时。使用EZ-96 DNA甲基化试剂盒（Zymo Research）完成亚硫酸氢盐转化实验。随后按照Illumina Infinium HD甲基化检测试剂盒操作流程，将处理后的DNA样本与Infinium甲基化EPIC v2.0芯片进行杂交。