Wang Jian, Li Shujing, Li Xiahui, Li Bowen, Li Yanan, Xia Kangkai, Yang Yuxi, Aman Sattout, Wang Miao, Wu Huijian
Province Key Laboratory of Protein Modification and Occurrence of Disease, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024 Liaoning Province China.
Cancer Cell Int. 2019 Jul 16;19:182. doi: 10.1186/s12935-019-0902-2. eCollection 2019.
Metastasis is an important factor in the poor prognosis of breast cancer. As an important core clock protein, brain and muscle arnt-like 1 (BMAL1) is closely related to tumorigenesis. However, the molecular mechanisms that mediate the role of BMAL1 in invasion and metastasis remain largely unknown. In this study, we investigated the BMAL1 may take a crucial effect in the progression of breast cancer cells.
BMAL1 and MMP9 expression was measured in breast cell lines. Transwell and scratch wound-healing assays were used to detect the movement of cells and MTT assays and clonal formation assays were used to assess cells' proliferation. The effects of BMAL1 on the MMP9/NF-κB pathway were examined by western blotting, co-immunoprecipitation and mammalian two-hybrid.
In our study, it showed that cell migration and invasion were significantly enhanced when overexpressed BMAL1. Functionally, overexpression BMAL1 significantly increased the mRNA and protein level of matrix metalloproteinase9 (MMP9) and improved the activity of MMP9. Moreover, BMAL1 activated the NF-κB signaling pathway by increasing the phosphorylation of IκB and promoted human MMP9 promoter activity by interacting with NF-kB p65, leading to increased expression of MMP9. When overexpressed BMAL1, CBP (CREB binding protein) was recruited to enhance the activity of p65 and further activate the NF-κB signaling pathway to regulate the expression of its downstream target genes, including MMP9, TNFα, uPA and IL8, and then promote the invasion and metastasis of breast cancer cells.
This study confirmed a new mechanism by which BMAL1 up-regulated MMP9 expression to increase breast cancer metastasis, to provide research support for the prevention and treatment of breast cancer.
转移是乳腺癌预后不良的一个重要因素。作为一种重要的核心时钟蛋白，脑和肌肉芳香烃受体核转运蛋白样1（BMAL1）与肿瘤发生密切相关。然而，介导BMAL1在侵袭和转移中作用的分子机制仍 largely 未知。在本研究中，我们调查了BMAL1可能在乳腺癌细胞进展中起关键作用。
在乳腺癌细胞系中检测BMAL1和基质金属蛋白酶9（MMP9）的表达。采用 Transwell 和划痕伤口愈合试验检测细胞迁移，采用MTT试验和克隆形成试验评估细胞增殖。通过蛋白质印迹、免疫共沉淀和哺乳动物双杂交检测BMAL1对MMP9/NF-κB通路的影响。
在我们的研究中，结果显示过表达BMAL1时细胞迁移和侵袭显著增强。在功能上，过表达BMAL1显著增加基质金属蛋白酶9（MMP9）的mRNA和蛋白水平并提高MMP9的活性。此外，BMAL1通过增加IκB的磷酸化激活NF-κB信号通路，并通过与NF-κB p65相互作用促进人MMP9启动子活性，导致MMP9表达增加。当过表达BMAL1时，募集 CREB 结合蛋白（CBP）以增强p65的活性并进一步激活NF-κB信号通路以调节其下游靶基因的表达，包括MMP9、肿瘤坏死因子α（TNFα）、尿激酶型纤溶酶原激活剂（uPA）和白细胞介素8（IL8），进而促进乳腺癌细胞的侵袭和转移。
本研究证实了BMAL1上调MMP9表达以增加乳腺癌转移的新机制，为乳腺癌的防治提供研究支持。
