Chen Miaojiao, Zhang Jingjing, Hu Fang, Liu Shiping, Zhou Zhiguang
Institute of Metabolism and Endocrinology, the Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
Diabetes Center of Central South University, Changsha, Hunan, China.
Diabetes Metab Res Rev. 2015 Nov;31(8):781-9. doi: 10.1002/dmrr.2761. Epub 2015 Nov 20.
Accumulating evidence suggests an association between diabetes and cancer. Inflammation is a key event that underlies the pathological processes of the two diseases. Metformin displays anti-cancer effects, but the mechanism is not completely clear. This study investigated whether metformin regulated the microenvironment of macrophage polarization to affect the characteristics of HepG2 cells and the possible role of the Notch-signalling pathway.
RAW264.7 macrophages were cultured alone or co-cultured with HepG2 cells and treated with metformin. We analysed classical (M1) and alternative (M2) gene expression in RAW264.7 cells using quantitative real-time polymerase chain reaction. Changes in mRNA and protein expressions of Notch signalling in both cell types were also detected using quantitative real-time polymerase chain reaction and Western-blotting analyses. The proliferation, apoptosis and migration of HepG2 cells were detected using Cell Titer 96 AQueous One Solution Cell Proliferation Assay (MTS) (Promega Corporation, Fitchburg, WI, USA), Annexin V-FITC/PI (7SeaPharmTech, Shanghai, China) and the cell scratch assay, respectively.
Metformin induced single-cultured RAW264.7 macrophages with an M2 phenotype but attenuated the M2 macrophage differentiation and inhibited monocyte chemoattractant protein-1 (MCP-1) secretion in a co-culture system. The co-cultured group of metformin pretreatment activated Notch signalling in macrophages but repressed it inHepG2 cells. Co-culture also promoted the proliferation and migration of HepG2 cells. However, along with the enhanced apoptosis, the proliferation and the migration of HepG2 cells were remarkably inhibited in another co-culture system with metformin pretreatment.
Metformin can skew RAW264.7 macrophages toward different phenotypes according to changes in the microenvironment, which may affect the inflammatory conditions mediated by macrophages, induce apoptosis and inhibit the proliferation and migration of HepG2 cells. Notch signalling pathway is a potentially important mechanism in the regulation of metformin on macrophage polarization and the subsequent change of hepatoma cells. Copyright © 2015 John Wiley & Sons, Ltd.
越来越多的证据表明糖尿病与癌症之间存在关联。炎症是这两种疾病病理过程的关键事件。二甲双胍具有抗癌作用，但其机制尚不完全清楚。本研究调查了二甲双胍是否通过调节巨噬细胞极化的微环境来影响HepG2细胞的特性以及Notch信号通路的可能作用。
将RAW264.7巨噬细胞单独培养或与HepG2细胞共培养，并给予二甲双胍处理。我们使用定量实时聚合酶链反应分析RAW264.7细胞中经典（M1）和替代（M2）基因的表达。还使用定量实时聚合酶链反应和蛋白质免疫印迹分析检测两种细胞类型中Notch信号的mRNA和蛋白质表达变化。分别使用细胞增殖检测试剂盒（MTS）（美国威斯康星州菲奇堡的Promega公司）、膜联蛋白V-FITC/PI（中国上海的7SeaPharmTech公司）和细胞划痕试验检测HepG2细胞的增殖、凋亡和迁移。
二甲双胍诱导单培养的RAW264.7巨噬细胞呈现M2表型，但在共培养系统中减弱了M2巨噬细胞的分化并抑制单核细胞趋化蛋白-1（MCP-1）的分泌。二甲双胍预处理的共培养组激活了巨噬细胞中的Notch信号，但在HepG2细胞中则抑制了该信号。共培养还促进了HepG2细胞的增殖和迁移。然而，在另一个经过二甲双胍预处理的共培养系统中，随着凋亡增加，HepG2细胞的增殖和迁移受到显著抑制。
二甲双胍可根据微环境的变化使RAW264.7巨噬细胞偏向不同表型，这可能影响巨噬细胞介导的炎症状态，诱导凋亡并抑制HepG2细胞的增殖和迁移。Notch信号通路是二甲双胍调节巨噬细胞极化及随后肝癌细胞变化的潜在重要机制。版权所有© 2015约翰威立父子有限公司。
