Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China.
Tianjin Neurological Institute, Key Laboratory of Post-neurotrauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Tianjin 300052, China.
Theranostics. 2022 May 16;12(9):4330-4347. doi: 10.7150/thno.71763. eCollection 2022.
The concentration and duration of intracellular drugs have always been the key factors for determining the efficacy of the treatment. Efflux of chemotherapeutic drugs or anticancer agents is a major reason for multidrug resistance generation in cancer cells. The high expression of polymerase I and transcript release factor (PTRF) is correlated with a worse prognosis in glioma patients. However, the importance of PTRF on temozolomide (TMZ) resistance in glioblastoma (GBM) is poorly understood. TCGA data analysis, CGGA data analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), clone formation, cell counting kit-8 (cck-8), western blot (WB), immunofluorescence (IF), immunohistochemistry (IHC) and flow cytometry assays were performed to investigate the underlying mechanism and effect of PTRF on TMZ-resistance in a variety of GBM cell lines and GBM patient-derived xenograft (PDX) models. Clone formation, WB, IF, IHC and flow cytometry assays were performed to examine the efficacy of sequential therapy of TMZ followed by CQ in GBM cells and PDX models. The prognosis of GBM patients treated with TMZ was negatively correlated with PTRF expression. Our results reveal that PTRF knockdown significantly decrease proliferation and increase apoptosis in GBM after TMZ treatment. Moreover, PTRF contribute to TMZ-resistance by increasing TMZ efflux through extracellular vesicles (EVs). Furthermore, our results demonstrate that sequential therapy of TMZ followed by CQ significantly promotes the TMZ efficacy against GBM by increasing intracellular TMZ concentration ([TMZ]i). This study highlights that PTRF can act as an independent biomarker to predict the prognosis of GBM patients after TMZ treatment and describes a new mechanism contributing to TMZ-resistance. In addition, this study may provide a novel idea for GBM therapy.
细胞内药物的浓度和持续时间一直是决定治疗效果的关键因素。化疗药物或抗癌药物的外排是癌细胞产生多药耐药的主要原因。聚合酶 I 和转录释放因子 (PTRF) 的高表达与胶质瘤患者的预后较差相关。然而,PTRF 对替莫唑胺 (TMZ) 耐药在胶质母细胞瘤 (GBM) 中的重要性知之甚少。通过 TCGA 数据分析、CGGA 数据分析、透射电子显微镜 (TEM)、扫描电子显微镜 (SEM)、克隆形成、细胞计数试剂盒-8 (cck-8)、western blot (WB)、免疫荧光 (IF)、免疫组化 (IHC) 和流式细胞术检测,研究了 PTRF 在多种 GBM 细胞系和 GBM 患者来源异种移植 (PDX) 模型中对 TMZ 耐药的潜在机制和作用。通过克隆形成、WB、IF、IHC 和流式细胞术检测,研究了 TMZ 序贯治疗在 GBM 细胞和 PDX 模型中的疗效。接受 TMZ 治疗的 GBM 患者的预后与 PTRF 表达呈负相关。我们的研究结果表明,PTRF 敲低可显著降低 TMZ 处理后的 GBM 增殖并增加细胞凋亡。此外,PTRF 通过增加细胞外囊泡 (EVs) 中外排 TMZ 来促进 TMZ 耐药。此外,我们的研究结果表明,TMZ 序贯治疗后用 CQ 治疗可通过增加细胞内 TMZ 浓度 ([TMZ]i) 显著提高 TMZ 对 GBM 的疗效。 本研究强调 PTRF 可作为独立的生物标志物预测 TMZ 治疗后 GBM 患者的预后,并描述了一种新的 TMZ 耐药机制。此外,该研究可能为 GBM 治疗提供新的思路。