文献检索，用中文搜 PubMed

BACKGROUNDTargeted arterial infusion of verapamil combined with chemotherapy (TVCC) is an effective clinical interventional therapy for esophageal squamous cell carcinoma (ESCC), but multidrug resistance (MDR) remains the major cause of relapse or poor prognosis, and the underlying molecular mechanisms of MDR, temporal intratumoral heterogeneity, and clonal evolutionary processes of resistance have not been determined.METHODSTo elucidate the roles of genetic and epigenetic alterations in the evolution of acquired resistance during therapies, we performed whole-exome sequencing on 16 serial specimens from 7 patients with ESCC at every cycle of therapeutic intervention from 3 groups, complete response, partial response, and progressive disease, and we performed whole-genome bisulfite sequencing for 3 of these 7 patients, 1 patient from each group.RESULTSPatients with progressive disease exhibited a substantially higher genomic and epigenomic temporal heterogeneity. Subclonal expansions driven by the beneficial new mutations were observed during combined therapies, which explained the emergence of MDR. Notably, SLC7A8 was identified as a potentially novel MDR gene, and functional assays demonstrated that mutant SLC7A8 promoted the resistance phenotypes of ESCC cell lines. Promoter methylation dynamics during treatments revealed 8 drug resistance protein-coding genes characterized by hypomethylation in promoter regions. Intriguingly, promoter hypomethylation of SLC8A3 and mutant SLC7A8 were enriched in an identical pathway, protein digestion and absorption, indicating a potentially novel MDR mechanism during treatments.CONCLUSIONOur integrated multiomics investigations revealed the dynamics of temporal genetic and epigenetic inter- and intratumoral heterogeneity, clonal evolutionary processes, and epigenomic changes, providing potential MDR therapeutic targets in treatment-resistant patients with ESCC during combined therapies.FUNDINGNational Natural Science Foundation of China, Science Foundation of Peking University Cancer Hospital, CAMS Innovation Fund for Medical Sciences, Major Program of Shenzhen Bay Laboratory, Guangdong Basic and Applied Basic Research Foundation, and the third round of public welfare development and reform pilot projects of Beijing Municipal Medical Research Institutes.

背景

维拉帕米靶向动脉灌注联合化疗（TVCC）是治疗食管鳞癌（ESCC）的有效临床介入治疗方法，但多药耐药（MDR）仍是复发或预后不良的主要原因，MDR 的潜在分子机制、肿瘤内时间异质性和耐药的克隆进化过程尚未确定。

方法

为了阐明遗传和表观遗传改变在治疗过程中获得性耐药进化中的作用，我们对 7 名 ESCC 患者的 16 个连续标本进行了全外显子组测序，这些标本来自于 3 个治疗干预组：完全缓解、部分缓解和疾病进展。我们对其中的 3 名患者进行了全基因组亚硫酸氢盐测序，每组 1 名患者。

结果

疾病进展患者表现出明显更高的基因组和表观基因组时间异质性。在联合治疗期间，有利的新突变驱动了亚克隆的扩张，解释了 MDR 的出现。值得注意的是，SLC7A8 被鉴定为一个潜在的新的 MDR 基因，功能测定表明突变 SLC7A8 促进了 ESCC 细胞系的耐药表型。治疗过程中启动子甲基化动力学显示 8 个药物抗性蛋白编码基因的启动子区域呈低甲基化。有趣的是，SLC8A3 和突变 SLC7A8 的启动子低甲基化在蛋白质消化和吸收途径中富集，表明治疗过程中存在一种潜在的新的 MDR 机制。