He Hua, Xia Harry Hua-Xiang, Wang Ji De, Gu Qing, Lin Marie C M, Zou Bing, Lam Shiu Kum, Chan Annie O O, Yuen Man Fung, Kung Hsiang Fu, Wong Benjamin Chun-Yu
Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Cancer. 2006 Mar 15;106(6):1243-9. doi: 10.1002/cncr.21694.
Telomerase activation, which is observed in most human cancers, plays an important role in carcinogenesis. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activity. The aim of the study was to investigate whether nonsteroidal antiinflammatory drugs (NSAIDs) inhibit telomerase activity and hTERT.
Four colon carcinoma cell lines, HT-29, COLO205, CRL-2134, and SW1116, were used in the experiments. Polymerase chain reaction-based telomeric repeat amplification (TRAP) enzyme-linked immunosorbent assay (ELISA) was used to measure telomerase activity in the cells after treatment with aspirin, indomethacin, or SC-236 (a specific cyclooxygenase-2 [COX-2] inhibitor). Expression of hTERT mRNA and protein was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The dual luciferase reporter assay was performed to identify the potential cis-response elements to NSAIDs in the promoter region of hTERT.
Aspirin, indomethacin, and SC-236 inhibited telomerase activity in HT-29, COLO205, and CRL-2134 cell lines, but not in the SW1116 cell line. NSAIDs inhibited hTERT mRNA and protein expression through suppression of hTERT transcriptional activity. The hTERT promoter fragment -145 to -330 basepairs (bp) upstream of the ATG starting site was sufficient to respond to the NSAID-induced inhibitory effect and the inhibition was COX-2-independent.
NSAIDs inhibit telomerase activity at hTERT transcriptional, mRNA, and protein levels in colon carcinoma cells. The hTERT promoter fragment -145 to -330 bp may be the cis-response element to NSAIDs.
端粒酶激活在大多数人类癌症中都有观察到，在致癌过程中起重要作用。人端粒酶逆转录酶（hTERT）是端粒酶的一个亚基，对端粒酶活性至关重要。本研究的目的是调查非甾体抗炎药（NSAIDs）是否抑制端粒酶活性和hTERT。
实验使用了四种结肠癌细胞系，HT-29、COLO205、CRL-2134和SW1116。基于聚合酶链反应的端粒重复序列扩增（TRAP）酶联免疫吸附测定（ELISA）用于测量用阿司匹林、吲哚美辛或SC-236（一种特异性环氧化酶-2 [COX-2]抑制剂）处理后细胞中的端粒酶活性。分别通过逆转录-聚合酶链反应（RT-PCR）和蛋白质印迹法检测hTERT mRNA和蛋白质的表达。进行双荧光素酶报告基因测定以鉴定hTERT启动子区域中对NSAIDs的潜在顺式反应元件。
阿司匹林、吲哚美辛和SC-236抑制了HT-29、COLO205和CRL-2134细胞系中的端粒酶活性，但对SW1116细胞系没有抑制作用。NSAIDs通过抑制hTERT转录活性来抑制hTERT mRNA和蛋白质表达。hTERT启动子片段在ATG起始位点上游-145至-330碱基对（bp）足以响应NSAID诱导的抑制作用，且该抑制作用不依赖于COX-2。
NSAIDs在结肠癌细胞中在hTERT转录、mRNA和蛋白质水平上抑制端粒酶活性。hTERT启动子片段-145至-330 bp可能是对NSAIDs的顺式反应元件。
