Functional screening implicates miR-371-3p and peroxiredoxin 6 in reversible tolerance to cancer drugs [SPR899]. Homo sapiens

Acquired resistance to cancer drug therapies almost always occurs in advanced-stage patients even following a significant response to treatment. In addition to mutational mechanisms, various non-mutational resistance mechanisms have now been recognized. We previously described a chromatin-mediated subpopulation of reversibly drug-tolerant persisters (DTPs) that is dynamically maintained within a wide variety of tumor cell populations. Here, we explored a potential role for microRNAs in such transient drug tolerance. Functional screening of 879 human microRNAs revealed miR-371-3p as a potent suppressor of drug tolerance. PRDX6 (peroxiredoxin 6) was identified as a key target of miR-371-3p in establishing drug tolerance by regulating PLA2/PKCα activity and reactive oxygen species. PRDX6 expression is associated with poor prognosis in cancers of multiple tissue origins. These findings implicate miR-371-3p as a suppressor of PRDX6 and suggest that co-targeting of PRDX6 or modulating miR-371-3p expression together with targeted cancer therapies may delay or prevent acquired drug resistance. Overall design: Drug tolerant persisters (DTPs) generated in response to erlotinib treatment were the basis for RNA extraction and hybridization on Affymetrix microarrays. PC9 cells were treated with DMSO or Erlotinib for 9 days to generate DTPs, then RNA was isolated for analyzing the differential gene expression pattern in DTPs compared to parental cells.

癌症药物治疗的获得性耐药几乎总会在晚期患者中出现，即便患者此前已对治疗产生显著应答。除突变机制外，目前已证实存在多种非突变型耐药机制。本团队此前曾报道过一类由染色质介导的可逆性耐药耐受持久细胞（drug-tolerant persisters，DTPs）亚群，该亚群可在多种肿瘤细胞群体中动态维持。本研究针对微小核糖核酸（microRNAs，miRNAs）在这类瞬时耐药耐受过程中的潜在作用展开探索。对879种人类微小核糖核酸进行功能筛选后，发现miR-371-3p是强效的耐药耐受抑制剂。过氧化物还原酶6（peroxiredoxin 6，PRDX6）被鉴定为miR-371-3p的关键靶标，其通过调控磷脂酶A2/蛋白激酶Cα（PLA2/PKCα）活性与活性氧（reactive oxygen species，ROS）参与耐药耐受的建立。PRDX6的表达水平与多种组织起源癌症的不良预后显著相关。上述研究结果表明，miR-371-3p可作为PRDX6的抑制剂，同时提示将PRDX6联合靶向治疗，或联合调节miR-371-3p表达与癌症靶向治疗，或可延缓甚至阻止获得性耐药的发生。整体实验设计：以厄洛替尼（erlotinib）处理诱导产生的耐药耐受持久细胞（DTPs）为实验材料，进行核糖核酸（RNA）提取并在Affymetrix基因芯片上完成杂交。将PC9细胞用二甲基亚砜（dimethyl sulfoxide，DMSO）或厄洛替尼处理9天以诱导产生DTPs，随后分离RNA，分析DTPs与亲代细胞之间的差异基因表达谱。