Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China.
Department of Otolarynology, Chongqing Medical University, Chongqing, 400016, China.
Cell Oncol (Dordr). 2017 Dec;40(6):537-547. doi: 10.1007/s13402-017-0342-8. Epub 2017 Aug 2.
Previously, it has been shown that obesity may be considered as a risk factor for breast cancer in postmenopausal women. Leptin, a hormone whose level is elevated in obesity, has been suggested to be involved in the development of breast cancer, and univariate survival analyses have shown that over-expression of ACAT2, an enzyme that is involved in the production of cholesteryl esters, may be associated with a poor prognosis. Here, we aimed to investigate the effect of leptin on the proliferation, migration and invasion of breast cancer cells, as well as to elucidate its underlying mode of action.
Gene expression changes in leptin treated breast cancer-derived MCF-7, T47D and BT474 cells were assessed using PCR array, qRT-PCR and Western blot analyses. The expression patterns of Ob-R (leptin receptor) and ACAT2 in breast cancer cells and primary breast cancer tissue samples were analyzed using immunofluorescence and immunohistochemistry, respectively. Leptin-induced proliferation of breast cancer cells was assessed using a CCK8 assay, and scratch wound and Transwell assays were used to assess breast cancer cell invasion and migration.
We found that, among the genes tested, ACAT2 expression exhibited the most significant changes in the leptin treated cells. In addition, we found that inhibition of ACAT2 expression using pyripyropene A (PPPA) or siRNA-mediated gene silencing significantly decreased leptin-induced proliferation, migration and invasion of MCF-7 and T47D cells. Subsequent Western blot analyses strongly indicated that the PI3K/AKT/SREBP2 signaling pathway was involved in leptin-induced ACAT2 upregulation in both MCF-7 and T47D cells. Finally, through the analysis of primary breast cancer tissue samples we found that ACAT2 may affect cancer progression through activation of the Ob-R.
Our data indicate that leptin may enhance the proliferation, migration and invasion of breast cancer cells via ACAT2 up-regulation through the PI3K/AKT/SREBP2 signaling pathway. Therefore, the leptin/ACAT2 axis may represent an attractive therapeutic target for breast cancer, particularly in postmenopausal and/or obese women.
此前已有研究表明，肥胖可能被视为绝经后女性乳腺癌的一个危险因素。瘦素是一种在肥胖症中水平升高的激素，它被认为参与了乳腺癌的发生，并且单变量生存分析表明，参与胆固醇酯生成的酶 ACAT2 的过表达可能与预后不良有关。在这里，我们旨在研究瘦素对乳腺癌细胞增殖、迁移和侵袭的影响，并阐明其潜在的作用机制。
使用 PCR 阵列、qRT-PCR 和 Western blot 分析评估瘦素处理的乳腺癌衍生 MCF-7、T47D 和 BT474 细胞中的基因表达变化。使用免疫荧光和免疫组织化学分别分析乳腺癌细胞和原发性乳腺癌组织样本中 Ob-R（瘦素受体）和 ACAT2 的表达模式。使用 CCK8 测定法评估瘦素诱导的乳腺癌细胞增殖，使用划痕伤口和 Transwell 测定法评估乳腺癌细胞的迁移和侵袭。
我们发现，在所测试的基因中，ACAT2 的表达在瘦素处理的细胞中变化最为显著。此外，我们发现，使用吡嗪哌啶 A（PPPA）或 siRNA 介导的基因沉默抑制 ACAT2 表达可显著降低 MCF-7 和 T47D 细胞中瘦素诱导的增殖、迁移和侵袭。随后的 Western blot 分析强烈表明，PI3K/AKT/SREBP2 信号通路参与了 MCF-7 和 T47D 细胞中瘦素诱导的 ACAT2 上调。最后，通过对原发性乳腺癌组织样本的分析，我们发现 ACAT2 可能通过激活 Ob-R 影响癌症的进展。
我们的数据表明，瘦素可能通过 PI3K/AKT/SREBP2 信号通路通过上调 ACAT2 来增强乳腺癌细胞的增殖、迁移和侵袭。因此，瘦素/ACAT2 轴可能代表治疗乳腺癌的一个有吸引力的靶点，特别是在绝经后和/或肥胖的女性中。
