Long Cong, Xu Qiu-Bo, Ding Li, Yang Liu, Ji Wei, Gao Feng, Ji Yong
Clinical Laboratory, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China.
Department of General Surgery, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China.
Oncol Lett. 2021 Apr;21(4):280. doi: 10.3892/ol.2021.12541. Epub 2021 Feb 10.
Epstein-Barr virus (EBV) mainly causes infectious mononucleosis and is associated with several neoplasms, including Burkitt's lymphoma, nasopharyngeal carcinoma and lymphoproliferative disease. Human telomerase reverse transcriptase (hTERT) regulates enzymatic activity of telomerase and is closely associated with tumorigenesis and senescence evasion. Triptolide (TP) is a diterpenoid triepoxide, with a broad-spectrum anticancer and immunosuppressive bioactivity profile. The present study investigated whether TP inhibited hTERT expression and suppressed its activity. The mRNA and protein levels of hTERT were examined by reverse transcription-quantitative PCR and western blotting. The activity of hTERT promoter was determined by dual-luciferase reporter assay. Cell Counting Kit-8 assays were performed to analyze cell proliferation. The present study used EBV-positive B lymphoma cells as a model system, and the results demonstrated that TP significantly decreased hTERT transcription and protein expression. Mechanistically, TP attenuated the hTERT promoter activity by downregulating the expression levels of specificityprotein 1 and c-Myc transcription factors. Consistently, inhibition of hTERT via shRNA transfection efficiently enhanced the suppression of cell proliferation by TP. Furthermore, TP increased virus latent replication and promoted the lytic cycle of EBV in EBV-positive B lymphoma cells, increasing the number of lytic cells and inhibiting the viability of tumor cells. Taken together, the results of the present study revealed a molecular mechanism of the pharmacological inhibition of tumor cell proliferation by TP, encouraging the translation of TP-based therapeutics in EBV-positive B lymphoma treatment.
爱泼斯坦-巴尔病毒(EBV)主要引起传染性单核细胞增多症,并与多种肿瘤相关,包括伯基特淋巴瘤、鼻咽癌和淋巴增殖性疾病。人端粒酶逆转录酶(hTERT)调节端粒酶的酶活性,与肿瘤发生和衰老逃避密切相关。雷公藤甲素(TP)是一种二萜类三环氧化物,具有广谱抗癌和免疫抑制生物活性。本研究调查了TP是否抑制hTERT表达并抑制其活性。通过逆转录定量PCR和蛋白质印迹法检测hTERT的mRNA和蛋白质水平。通过双荧光素酶报告基因测定法测定hTERT启动子的活性。进行细胞计数试剂盒-8测定以分析细胞增殖。本研究以EBV阳性B淋巴瘤细胞为模型系统,结果表明TP显著降低hTERT转录和蛋白质表达。机制上,TP通过下调特异性蛋白1和c-Myc转录因子的表达水平来减弱hTERT启动子活性。一致地,通过shRNA转染抑制hTERT有效地增强了TP对细胞增殖的抑制作用。此外,TP增加了病毒潜伏复制并促进了EBV在EBV阳性B淋巴瘤细胞中的裂解周期,增加了裂解细胞的数量并抑制了肿瘤细胞的活力。综上所述,本研究结果揭示了TP药理抑制肿瘤细胞增殖的分子机制,为基于TP的疗法在EBV阳性B淋巴瘤治疗中的转化应用提供了依据。