Cheng Meixiong, Wang Qi, Chen Longyi, Zhao Dongdong, Tang Jian, Xu Jianguo, He Zongze
Department of Neurosurgery, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China; Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.
Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.
Hum Pathol. 2022 May;123:59-73. doi: 10.1016/j.humpath.2022.02.016. Epub 2022 Feb 25.
Glioblastoma (GBM) is the most malignant subtype of gliomas. GBM resistance to temozolomide (TMZ) remains a huge challenge. O6-methylguanine-DNA methyltransferase (MGMT) is mainly responsible for repairing DNA alkylation damage caused by alkylating drugs such as TMZ; therefore, it has been regarded as the major cause of the resistance to TMZ. Hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining were performed in tissue sections. LncRNA urothelial cancer-associated 1 (UCA1) knockdown was conducted via the transfection of the plasmid containing small interfering RNA (siRNA) targeting lncRNA UCA1. Cell viability and apoptosis were examined using MTT assay and flow cytometry. Nude mouse tumorigenicity assay was performed to detect tumor formation in vivo. MGMT expression and lncRNA UCA1 expression were increased in high-grade glioma tissues and cells. UCA1 knockdown in glioma cells enhanced TMZ efficacies in affecting glioma cell viability, cell apoptosis, MGMT protein level, and DNA damage markers in vitro, as well as tumorigenesis in vivo. Moreover, miR-182-5p targeted UCA1 and MGMT; miR-182-5p inhibited MGMT expression. Similar to UCA1 knockdown, miR-182-5p overexpression also promoted TMZ effects on glioma cell phenotype, MGMT expression level, and the levels of DNA damage markers. Under TMZ treatment, the efficacies of UCA1 knockdown in MGMT expression level and glioma cell sensitivity to TMZ were notably reversed after miR-182-5p overexpression. Taken together, we demonstrate the lncRNA UCA1/miR-182-5p/MGMT axis modulates glioma cell sensitivity to TMZ via MGMT-related DNA damage pathways.
胶质母细胞瘤（GBM）是胶质瘤中最恶性的亚型。GBM对替莫唑胺（TMZ）耐药仍然是一个巨大的挑战。O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）主要负责修复由TMZ等烷化剂药物引起的DNA烷基化损伤；因此，它被认为是TMZ耐药的主要原因。对组织切片进行苏木精和伊红（H&E）染色及免疫组化（IHC）染色。通过转染含有靶向lncRNA UCA1的小干扰RNA（siRNA）的质粒来敲低lncRNA尿路上皮癌相关1（UCA1）。使用MTT法和流式细胞术检测细胞活力和凋亡。进行裸鼠成瘤实验以检测体内肿瘤形成情况。高级别胶质瘤组织和细胞中MGMT表达和lncRNA UCA1表达增加。敲低胶质瘤细胞中的UCA1可增强TMZ在体外影响胶质瘤细胞活力、细胞凋亡、MGMT蛋白水平和DNA损伤标志物的效果，以及在体内的肿瘤发生。此外，miR-182-5p靶向UCA1和MGMT；miR-182-5p抑制MGMT表达。与敲低UCA1相似，过表达miR-182-5p也促进了TMZ对胶质瘤细胞表型、MGMT表达水平和DNA损伤标志物水平的影响。在TMZ处理下，过表达miR-182-5p后，敲低UCA1在MGMT表达水平和胶质瘤细胞对TMZ敏感性方面的效果显著逆转。综上所述，我们证明lncRNA UCA1/miR-182-5p/MGMT轴通过与MGMT相关的DNA损伤途径调节胶质瘤细胞对TMZ的敏感性。
