瘦素诱导乳腺癌细胞中端粒酶反转录酶表达的机制  

Leptin promotes the expression of hTERT via STAT3 in breast cancer cells

作　　者：李莎莎[1] 盛俊[1] 苑占娜[1] 王秀超[1] 赵天锁[1] 任贺[1] 郝继辉[1] 

机构地区：[1]天津医科大学附属肿瘤医院中心实验室天津市肿瘤防治重点实验室乳腺癌防治教育部重点实验室,300060

出　　处：《中华医学杂志》2012年第34期2386-2388,共3页National Medical Journal of China

基　　金：国家自然科学基金（30973490）

摘　　要：目的探讨在乳腺癌细胞（MCF7）中瘦素诱导端粒酶反转录酶（hTERT）表达的分子机制。方法采用实时荧光定量逆转录聚合酶链反应（RT．PCR）法测定瘦素对沉默信号转导和转录激活因子3（STAq3）基因后MCF7细胞hTERTmRNA表达水平的影响。采用Western印迹方法测定MCF7细胞经不同处理后hTERT蛋白的表达变化。采用染色质免疫共沉淀（ChIP）技术观察STA33与hTERT启动子的结合情况。应用双荧光素酶分析，探讨瘦素及P-STAT3抑制剂（AG490）对hTERT启动子转录活性的影响。结果STAT3小干扰片段RNA（siRNA）转染细胞后，瘦素诱导的hTERTmRNA的表达减少。Western印迹结果示hTERT蛋白在瘦素处理组及AG490联合瘦素处理组的蛋白表达分别为3．1094-0．051、1．025±0．031，加入P—STAT3抑制剂AG490后，瘦素诱导hTERT蛋白表达明显减少（P〈0．01）。ChIP结果显示对照组与瘦素处理组mRNA分别为1、3．311±0．017，瘦素（160ng／m1）作用MCF7细胞后，增加了STA33与hTERT启动子之间的结合（P〈0．01）。双荧光素酶分析结果示，经瘦素（160ng／m1）作用后，hTERT启动子活性的变化倍率为80．98±0．18，对照组为20．76±0．31，加入AG490后，hTERT启动子活性的变化倍率为18．65±0．32，瘦素诱导的hTERT启动子的活性明显下降。结论在乳腺癌MCF7细胞中，瘦素／STA33信号通路是上调hTERT表达的可能机制。Objective To discussion the in vitro molecular mechanism of leptin promoting the expression of hTERT in breast cancer cells. Methods The hTERT mRNA expression of STAT3 knockdown on leptin-induced hTERT was measured by reverse transcription-polymerase chain reaction （ RT-PCR ） . Determine the expression of hTERT protein after different treatments in MCF7 by Western blot. Chromatin immunoprecipitation assay （CHIP） was performed to detect the binding of STAT3 to hTERT promoter in MCF7. Luciferase assay was used to confirm the effects of leptin and STAT3 phosphorylation inhibitor on the transcriptional activity of hTERT promoter. Results The RT-PCR analysis showed that knockdown of STAT3 significantly reduced the leptin-induced transcription of hTERT. Western blot showed that the expression of hTERT were 3. 109±0. 051 and 1. 025±0. 031 after leptin or both of leptin and AG490 treatments. The results of CHIP showed that the mRNA of control and leptin （ 160 ng/ml） treatment were 1 and 3. 311±0. 017. Leptin increased the combination of STAT3 and hTERT promoter. Luciferase assay showed that when the concentration of leptin was 160 ng/ml, the hTERT promoter activity was 80. 98±0. 18 while the control was 20. 76±0. 31. After AG490 treatment, the hTERT promoter activity was 18.65±0. 32, significantly reduced the leptin-induced activity of hTERT promoter. Conclusion Leptin/STAT3 signaling is a novel pathway for the up-regulation of hTERT expression in breast cancer ceils.

关 键 词：瘦素 乳腺肿瘤 MCF7细胞系 端粒酶逆转录酶 

分 类 号：R737.9[医药卫生—肿瘤]