Jiang Pengfei, Wang Ping, Sun Xiaoling, Yuan Zhongshun, Zhan Rucai, Ma Xiangyu, Li Weiguo
Medical Department, Yuhuangding Hospital, Yantai, People's Republic of China.
Neurosurgery Department, Qilu Hospital, Shandong University, Jinan, People's Republic of China.
Onco Targets Ther. 2016 Jun 13;9:3501-9. doi: 10.2147/OTT.S96278. eCollection 2016.
Temozolomide (TMZ) is commonly used in glioma chemotherapy. However, a great clinical challenge for TMZ is chemoresistance. H19 transcripts are recognized as long noncoding RNAs, which potentially interact with chromatin-modifying complexes to regulate gene expression via epigenetic changes. Our data based on glioma patients showed that the expression of H19 was significantly upregulated in TMZ-resistant tumors compared with the TMZ-sensitive tumors. To determine the function of H19 in glioma, cell lines U87 and U251 were exposed to TMZ to establish TMZ-resistant clones U87(TMZ) and U251(TMZ). In U87(TMZ) and U251(TMZ), the expression level of H19 transcripts was increased compared to wild-type or nonresistant clones, as determined by real-time quantitative reverse transcription polymerase chain reaction. Concomitant treatment with small interfering RNA specifically targeting H19 and TMZ in resistant glioma clones resulted in decreased IC50 values for TMZ, and increased apoptotic rates than control small interfering RNA-treated cells. This was also evident by the increased PARP cleavage in resistant cells exposed to TMZ + si-H19. Furthermore, the reduced expression of H19 altered major drug resistance genes, such as MDR, MRP, and ABCG2, both at the mRNA and protein levels. Taken together, these findings suggest that H19 plays an important role in the development of TMZ resistance, and may represent a novel therapeutic target for TMZ-resistant gliomas.
替莫唑胺（TMZ）常用于胶质瘤化疗。然而，TMZ面临的一个重大临床挑战是化疗耐药性。H19转录本被认为是长链非编码RNA，它可能与染色质修饰复合物相互作用，通过表观遗传变化来调节基因表达。我们基于胶质瘤患者的数据显示，与TMZ敏感肿瘤相比，H19在TMZ耐药肿瘤中的表达显著上调。为了确定H19在胶质瘤中的功能，将细胞系U87和U251暴露于TMZ以建立TMZ耐药克隆U87(TMZ)和U251(TMZ)。通过实时定量逆转录聚合酶链反应测定，与野生型或非耐药克隆相比，U87(TMZ)和U251(TMZ)中H19转录本的表达水平升高。在耐药胶质瘤克隆中，用特异性靶向H19的小干扰RNA与TMZ联合处理，导致TMZ的IC50值降低，凋亡率比对照小干扰RNA处理的细胞增加。在暴露于TMZ + si-H19的耐药细胞中PARP裂解增加也证明了这一点。此外，H19表达的降低在mRNA和蛋白质水平上改变了主要的耐药基因，如MDR、MRP和ABCG2。综上所述，这些发现表明H19在TMZ耐药性的发展中起重要作用，并且可能代表TMZ耐药胶质瘤的一个新的治疗靶点。
