Tuna Bilge Güvenç, Cleary Margot, Dogan Soner
Department of Biophysics, Yeditepe University Faculty of Medicine, İstanbul, Turkey.
University of Minnesota, Hormel Institute Medical Research Center, Austin, MN, USA.
South Clin Istanb Eurasia. 2019 Dec;30(4):290-295. doi: 10.14744/less.2019.85688.
This study aims to investigate the expression levels of adiponectin signaling related proteins in mammary tissue, liver and breast cancer tissue in mice. Adiponectin, an adipocytokine, is secreted from adipose tissue and has been documented to have roles in diabetes, inflammation, and cancer development. In particular, levels of serum adiponectin are inversely associated with obesity and a decrease in serum adiponectin levels have been reported to be associated with breast cancer. There are two adiponectin receptor subtypes, AdipoR1 and AdipoR2, which have been identified in mammalian tissues, including human cancer cell lines and also in human mammary tumors. However, the role of adiponectin receptors in breast cancer development remains to be established.
In this study, MMTV-TGF-α transgenic mice were fed from week 10 up to week 74 of age. Expression levels of adiponectin, AdipoR1 and AdipoR2 proteins were measured in the mammary fat pad (MFP), mammary tumor (MT) and liver tissues from 74 weeks old MMTV-TGF-α transgenic mice with and without MT using Western Blot. Adiponectin levels were measured using ELISA assay.
Protein expression levels of Adiponectin and AdipoR1 were significantly lower in MTs compared to control tissues. However, AdipoR2 protein expression levels were similar in MT and MFP tissues from MT-positive and MT-negative mice. The expression levels of adiponectin, AdipoR1 and AdipoR2 proteins in liver tissues were also similar in MT-positive and MT-negative mice. Serum adiponectin levels of the MT-positive and MT-negative mice were similar.
These results indicate that adiponectin and its receptors are differentially regulated depending upon the specific tissue analyzed. AdipoR1 and adiponectin may play important roles in MT development.
本研究旨在调查小鼠乳腺组织、肝脏和乳腺癌组织中脂联素信号相关蛋白的表达水平。脂联素是一种脂肪细胞因子，由脂肪组织分泌，已被证明在糖尿病、炎症和癌症发展中发挥作用。特别是，血清脂联素水平与肥胖呈负相关，据报道血清脂联素水平降低与乳腺癌有关。脂联素有两种受体亚型，即AdipoR1和AdipoR2，已在包括人类癌细胞系和人类乳腺肿瘤在内的哺乳动物组织中得到鉴定。然而，脂联素受体在乳腺癌发展中的作用仍有待确定。
在本研究中，MMTV-TGF-α转基因小鼠从10周龄喂养至74周龄。使用蛋白质免疫印迹法测量74周龄有或没有乳腺肿瘤的MMTV-TGF-α转基因小鼠的乳腺脂肪垫（MFP）、乳腺肿瘤（MT）和肝脏组织中脂联素、AdipoR1和AdipoR2蛋白的表达水平。使用酶联免疫吸附测定法测量脂联素水平。
与对照组织相比，MT中脂联素和AdipoR1的蛋白表达水平显著降低。然而，MT阳性和MT阴性小鼠的MT和MFP组织中AdipoR2蛋白表达水平相似。MT阳性和MT阴性小鼠肝脏组织中脂联素、AdipoR1和AdipoR2蛋白的表达水平也相似。MT阳性和MT阴性小鼠的血清脂联素水平相似。
这些结果表明，脂联素及其受体根据所分析的特定组织而受到不同的调节。AdipoR1和脂联素可能在MT发展中发挥重要作用。
