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摘要:
目的 观察瘦素(leptin)对乳腺癌细胞端粒酶的活性影响, 并探讨其可能的分子机制。 方法 采用ELISA检测瘦素对人乳腺癌细胞MCF-7端粒酶活性的影响。应用实时荧光定量PCR和Western blot法测定瘦素对MCF-7细胞人端粒酶逆转录酶(hTERT)及STAT3 mRNA和蛋白表达水平的影响。 结果 瘦素可增加MCF-7端粒酶的活性, 且呈剂量依赖性, 当浓度是10 nmol/L时, 活性增加2.8倍; 而采用瘦素受体单克隆抗体ZMC-2时则可明显抑制端粒酶的活性; 端粒酶的活性与hTERT紧密相关, 瘦素不仅增强了端粒酶的活性, 同时也增加了hTERTmRNA的表达水平, 且呈剂量依赖性, 经瘦素10 nmol/L处理后, hTERT蛋白表达水平增加2.9倍; 在瘦素处理MCF-7细胞后, hTERT的表达水平与磷酸化STAT3的水平呈现相关性上升, 提示STAT3途径可能参与了瘦素诱导hTERT的表达。 结论 在乳腺癌MCF-7细胞中, 瘦素可能通过STAT3途径促进hTERT的表达, 并最终上调端粒酶的活性。 -
关键词:
- 乳腺癌 /
- 瘦素 /
- 人端粒酶逆转录酶 /
- 端粒酶活性 /
- 信号转导和转录激活因子3
Abstract:Objective The present work aims to explore the potential molecular mechanism of increasing telomerase activity induced by leptin in breast cancer cells in vitro. Methods The leptin-mediated increase in telomerase activity in human breast cancer MCF-7 cells was determined using a TransAM enzyme-linked immunosorbent assay.Leptin-promoted human telomerase reverse transcriptase (hTERT) expression and signal transducer and activator transcription 3(STAT3) were analyzed through real-time polymerase chain reaction and Western blot analysis. Results Leptin improved the telomerase activity of MCF-7 cells in a dose-dependent manner.Telomerase activity increased 2.8-fold(P < 0.01) when the leptin concentration reached 10 nmol/L.ZMC-2, a leptin receptor monoclonal antibody, could significantly inhibit the leptin-induced activation of telomerase.Telomerase activity is closely related to the expression of hTERT.Leptin not only enhances telomerase activity, but also upregulates the hTERT mRNA level in a dose-dependent manner.After induction with 10 nmol/L leptin, the level of hTERT protein increased 2.9-fold(P < 0.01).Recently, STAT3 has been certified as a critical regulator of hTERT.Meanwhile, with the leptin treatment, the hTERT and phosphorylated STAT3 levels increased synchronously.This suggests that leptin-upregulated STAT3 may be involved in hTERT overexpression. Conclusion Leptin promotes hTERT expression in the MCF-7 human breast cancer cell line through the STAT3 pathway and ultimately increases telomerase activity. -
Key words:
- Breast cancer /
- Leptin /
- hTERT /
- Telomerase activity /
- Signal transducer and activator transcription 3
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图 2 瘦素及瘦素受体单克隆抗体对端粒酶活性的影响
*瘦素处理组与对照组及与加ZMC-2处理比较，P < 0.01
Figure 2. Effects of leptin and leptin receptor monoclonal antibody on telomerase activity
图 3 瘦素对hTERT mRNA表达水平的影响
*与未处理组比较，P < 0.01
Figure 3. Effect of leptin on the expression of hTERT mRNA levels
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[1] Lorincz AM, Sukumar S. Molecular links between obesity and breast cancer[J], Endocr Relat Cancer, 2006, 13(2): 279-292. [2] Perera CN, Chin HG, Duru N, et al. Leptin-regulated gene expression in MCF- 7 breast cancer cells', mechanistic insights into leptin-regulated mammary tumor growdi and progression[J]. J Endocrinol, 2008, 199(2): 221-233. doi: 10.1677/JOE-08-0215 [3] Cairney CJ, Keith WN. Telomerase redefined: integrated regulation of hTR and hTERT for telomere maintenance and telomerase activity[J]. Biochimie, 2008, 90(1): 13-23. doi: 10.1016/j.biochi.2007.07.025 [4] Shay JW, Bacchetti S. A survey of telomerase activity in human cancer[J]. Eur J Cancer, 1997, 33(5): 787-791. doi: 10.1016/S0959-8049(97)00062-2 [5] Schepelmann S, Ogilvie LM, Hedley D, et al. Suicide gene therapy of human colon carcinoma xenografts using an armed oncolytic adenovirus expressing carboxypeptidase G2[J]. Cancer Res, 2007, 67(10): 4949-4955. doi: 10.1158/0008-5472.CAN-07-0297 [6] Konnikova L, Simeone MC, Kruger MM, et al. Transducer and activator of transcription 3(STAT3) regulates human telomerase reverse transcriptase(hTERT) expression in human cancer and primary cells[J]. Cancer Res, 2005, 65(15): 6516-6520. doi: 10.1158/0008-5472.CAN-05-0924 [7] Frank DA. STAT3 as a central mediator of neoplastic cellular trans- formation[J]. Cancer Lett, 2007, 251(2): 199-210. doi: 10.1016/j.canlet.2006.10.017 [8] 刘义, 肖维, 龚成, 等. 瘦素对人乳腺癌细胞系MCF-7增殖的影响及其作用机制探讨[J]. 中华实验外科杂志, 2007, 24(12): 1551-1553. doi: 10.3760/j.issn:1001-9030.2007.12.036 [9] Saxena NK, Vertino PM, Anania FA, et al. Leptin-induced growth stimulation of breast cancer cells involves recruitment of histone acetyltransferases and mediator complex to CYCLIN D1 promoter via activation of Stat3[J]. J Biol Chem, 2007, 282(18): 13316-13325. doi: 10.1074/jbc.M609798200 [10] 曹文东, 杨涛, 郝斌, 等. 瘦素及瘦素受体在乳腺癌中的表达及临床意义[J]. 中华实验外科杂志, 2006, 23(2): 241-243. doi: 10.3760/j.issn:1001-9030.2006.02.041 [11] Jarde T, Caldefie-Chezet F, Goncalves-Mendes N, et al. Involvement of adiponectin and leptin in breast cancer: clinical and in vitro studies[J]. Endocr Relat Cancer, 2009, 16(4): 1197-1210. doi: 10.1677/ERC-09-0043 [12] Perera CN, Chin HG, Duru N, et al. Leptin-regulated gene expression in MCF-7 breast cancer cells: mechanistic insights into leptin-regulated mammary tumor growth and progression[J]. J Endocrinol, 2008, 199(2): 221-233. doi: 10.1677/JOE-08-0215 [13] Zhu Y, Wang W, Liu MC, et al. Estrogen receptor alpha positive breast tumors and breast cancer cell lines share similarities in their transcriptome data structures[J]. Int J Oncol, 2006, 29(6): 1581-1589. [14] Gao Q, Mezei G, Nie Y, et al. Anorectic estrogen mimics leptin's effect on the rewiring of melanocortin cells, Stat3 signaling in obese animals[J]. Nat Med, 2007, 13(1): 89-94. doi: 10.1038/nm1525 -
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