DNA Methylation Inhibitor Therapy for Testicular Cancer

睾丸生殖细胞肿瘤(TGCT)是年轻人最常见的癌症。目前可用的以顺铂为基础的 细胞毒性治疗会导致严重的急性和终生副作用，极大地影响生活质量。此外，15- 20%的病例是难治或复发的，尽管接受了顺铂治疗，而且是致命的。目前还没有可靠的预测。 制造者预测无响应者。这一应用是基于我们的新观察结果，即多能胚胎 肿瘤(EC)是TGCT的干细胞，对5-aza低剂量去甲基化治疗非常敏感。 脱氧胞苷(5-aza)和小剂量5-aza有效地介导启动子去甲基化和p53靶基因 表情。5-aza超敏反应延伸至顺铂耐药EC，5-aza预处理可恢复顺铂 对难耐细胞的敏感性。总而言之，这项工作为我们最近启动的和非常有希望的 第一阶段临床试验研究新型5-氮杂前体药物SGI-110对顺铂难治性TGCT患者的治疗作用。这样做的目的是 建议按顺序确定TGCT对DNA甲基化治疗超敏的确切分子机制(S 提供反应的理论基础和生物标志物，以支持未来基于表观遗传学的治疗睾丸的试验 癌症和其他实体肿瘤。假设TGCT，即使是那些对标准铂基的耐受性的 化疗，对低剂量的DNA甲基化抑制剂治疗过敏，也可以重新敏感 以顺铂为基础的治疗。我们还假设，多能TGCT细胞的特定表观遗传学特征使它们 容易受到DNA甲基化抑制剂治疗的影响，至少其中一些特征可以适用于罕见的癌症 躯体实体瘤中的起始细胞。我们的研究将使用细胞培养、人类异种移植和PDX的组合 模型和主要患者样本，包括正在进行的顺铂耐药SGI-110 I期试验的样本 TGCT。AIM 1将确定TGCT对5-氮杂/SGI-100和顺铂的敏感性是否源于 全基因组甲基化和染色质可及性。目标2将确定5-氮杂/SGI-110的作用机制 TGCT细胞的超敏反应是由于免疫监视通路的过度激活所致。AIM 3将验证这些 PDX和原位异种移植模型以及包括SGI-110期肿瘤在内的原发TGCT的研究结果 我进行了治疗试验。该项目将分子和表观遗传学生物学家与受人尊敬的面向临床的研究结合在一起。 将为针对TGCT表观基因组的干预奠定基础，并指导和影响未来的设计 临床调查。

Testicular germ cell tumors (TGCTs) are the most common carcinomas of young men. Currently available cisplatin-based cytotoxic therapies result in substantial acute and life-long side effects that greatly impact quality of life. In addition, 15- 20% of cases are refractory or relapse despite cisplatin therapy and are fatal. There are currently no reliable prognostic makers to predict non-responders. This application is based on our novel observations that pluripotent embryonal carcinoma (EC), the stem cells of TGCTs, are exquisitely sensitive to low dose demethylation treatment with 5-aza deoxycytidine (5-aza) and that low dose 5-aza is effective in mediating promoter demethylation and p53 target gene expression. The 5-aza hypersensitivity extends to cisplatin resistant EC and 5-aza pretreatment can restore cisplatin sensitivity to refractory cells. Together, this work provides the rationale for our recently initiated and highly promising phase I clinical trial to study the novel 5-aza prodrug SGI-110 in cisplatin refractory TGCT patients. The objective of this proposal is to define the precise molecular mechanism(s) of TGCT hypersensitivity to DNA methylation therapy in order to provide the rationale and biomarkers of response to support future epigenetic-based therapy trials to treat testicular cancer and other solid tumors. The hypothesis is that TGCTs, even those refractory to standard platinum based chemotherapy, are hypersensitive to low dose treatment with DNA methylation inhibitors and can also be resensitized to cisplatin based-therapy. We also hypothesize that specific epigenetic features of pluripotent TGCT cells make them vulnerable to DNA methylation inhibitor therapy and that at least some of these features could apply to rare cancer initiating cells in somatic solid tumors. Our studies will use a combination of cell culture, human xenograft and PDX models, and primary patient samples including samples from the ongoing Phase I trial of SGI-110 in cisplatin refractory TGCTs. Aim 1 will determine whether 5-aza/SGI-100 and cisplatin sensitivity in TGCTs is due to specific alterations in genome-wide methylation and chromatin accessibility. Aim 2 will determine whether the mechanism of 5-aza/SGI-110 hypersensitivity in TGCT cells is due to hyperactivation of immune surveillance pathways. Aim 3 will validate these findings in PDX and orthotopic xenograft models and in primary TGCTs including tumors from an ongoing SGI-110 phase I therapeutic trial. This project teams molecular and epigenetic biologists with an esteemed clinically oriented research group that will set the stage for interventions targeting the TGCT epigenome and guide and impact the design of future clinical investigations.