Department of Microbiology, Morehouse School of Medicine, Atlanta, GA 30310, USA.
Br J Cancer. 2011 Jan 4;104(1):128-37. doi: 10.1038/sj.bjc.6606013. Epub 2010 Dec 7.
Leptin and interleukin-1 (IL-1) upregulate vascular endothelial growth factor (VEGF), promote angiogenesis and are related to worse prognosis of breast cancer. However, it is unknown whether leptin regulates IL-1, and whether these effects are related to leptin-induction of VEGF/VEGFR2 in breast cancer.
Several genetic and pharmacological approaches were used to determine the mechanisms involved in leptin regulation of IL-1 system (IL-1α, IL-1β, IL-1Ra and IL-1R tI) and the impact of IL-1 signalling on leptin-induced VEGF/VEGFR2 expression in mouse mammary cancer 4T1 cells (a model that resembles invasive and highly metastatic human breast cancer).
Leptin increased protein and mRNA levels of all components of the IL-1 system. IL-1 upregulation involved leptin activation of JAK2/STAT3, MAPK/ERK 1/2, PI-3K/AKT1, PKC, p38 and JNK. Leptin-induced phosphorylation of mTOR/4E-BP1 increased IL-1β and IL-1Ra expression, but downregulated IL-1α. Leptin upregulation of IL-1α promoter was linked to SP1 and NF-κB transcription factors. In addition, leptin receptor (Ob-Rb) was upregulated by leptin. Interestingly, leptin upregulation of VEGF/VEGFR2 was partially mediated by IL-1/IL-1R tI signalling.
We show for the first time that leptin induces several signalling pathways to upregulate the translational and transcriptional expression of IL-1 system in breast cancer cells. Moreover, leptin upregulation of VEGF/VEGFR2 was impaired by IL-1 signalling blockade. These data suggest that leptin pro-angiogenic signature in breast cancer is linked to, or regulated, in part by IL-1 signalling.
瘦素和白细胞介素-1(IL-1)上调血管内皮生长因子(VEGF),促进血管生成,并与乳腺癌的预后不良相关。然而,目前尚不清楚瘦素是否调节 IL-1,以及这些作用是否与瘦素诱导的乳腺癌中 VEGF/VEGFR2 有关。
采用多种遗传和药理学方法,确定瘦素调节 IL-1 系统(IL-1α、IL-1β、IL-1Ra 和 IL-1R tI)的机制,以及 IL-1 信号对瘦素诱导的 4T1 细胞(一种类似于侵袭性和高度转移性人类乳腺癌的模型)中 VEGF/VEGFR2 表达的影响。
瘦素增加了 IL-1 系统的所有成分的蛋白和 mRNA 水平。IL-1 的上调涉及瘦素激活 JAK2/STAT3、MAPK/ERK 1/2、PI-3K/AKT1、PKC、p38 和 JNK。瘦素诱导的 mTOR/4E-BP1 磷酸化增加了 IL-1β 和 IL-1Ra 的表达,但下调了 IL-1α。瘦素对 IL-1α 启动子的上调与 SP1 和 NF-κB 转录因子有关。此外,瘦素还上调了瘦素受体(Ob-Rb)。有趣的是,瘦素对 VEGF/VEGFR2 的上调部分是由 IL-1/IL-1R tI 信号介导的。
我们首次表明,瘦素通过多种信号通路诱导乳腺癌细胞中 IL-1 系统的翻译和转录表达上调。此外,IL-1 信号阻断削弱了瘦素对 VEGF/VEGFR2 的上调。这些数据表明,瘦素在乳腺癌中的促血管生成特征与 IL-1 信号有关,或部分受其调节。