Feed-forward miR-181d degradation modulates population variance of methyl-guanine methyl transferase (MGMT) and temozolomide resistance

To characterize the changes in miRNA expression in response to TMZ therapy, two patient-derived glioblastoma cell lines BT-83 and CMK3 were treated with 500 μM TMZ or vehicle for 6 h. These cell lines were selected because their gene expression profile suggests they capture the two key glioblastoma cell states: BT-83 exhibits an expression pattern suggestive of the mesenchymal-like state, while CMK3 exhibits an expression pattern suggestive of the neural progenitor-like state45. RNA was extracted and profiled by RNA sequencing. In both cell lines, the TMZ treatment did not significantly alter the expression of >95% of the miRNAs.miRNAs exhibiting a >2-fold change in expression following TMZ treatment in both lines were individually assessed to determine whether their expression differed in matched pre- and post-TMZ-treated clinical glioblastoma specimens.Among the miRNAs evaluated, miR-181d was the only one consistently showing lowered levels in the post-TMZ specimens. This finding recapitulated our prior profiling experiment, where miR-181d was downregulated in post-TMZ-treated clinical glioblastoma specimens.

为阐明替莫唑胺（TMZ）治疗诱导的微小RNA（miRNA）表达变化，本研究选取两株患者来源的胶质母细胞瘤细胞系BT-83与CMK3，分别以500 μM替莫唑胺或溶剂对照处理6小时。选择该两株细胞系的原因在于，其基因表达谱可覆盖胶质母细胞瘤的两种核心细胞状态：BT-83的表达模式符合间质样细胞状态，而CMK3的表达模式则符合神经祖细胞样细胞状态45。提取总RNA后，通过RNA测序对样本进行表达谱分析。在两株细胞系中，替莫唑胺处理均未使超过95%的微小RNA表达发生显著改变。针对在两株细胞系中经替莫唑胺处理后表达变化幅度均超过2倍的微小RNA，本研究逐一评估其在配对的替莫唑胺治疗前后临床胶质母细胞瘤标本中的表达差异。在本次评估的微小RNA中，miR-181d是唯一在替莫唑胺治疗后标本中持续呈现表达水平下调的分子。该结果与本团队此前的表达谱实验结果一致，即miR-181d在替莫唑胺治疗后的临床胶质母细胞瘤标本中呈现下调表达。