Xiong Wei, Tan Junyu, Guo Yuxian, Chen Shuzhao, Fan Liping, Li Yaochen
The Central Laboratory of Cancer Hospital, Shantou University Medical College, Shantou, China.
Guangdong Provincial Key Laboratory of Breast Cancer Diagnosis and Treatment, Shantou, China.
Front Cell Dev Biol. 2020 Nov 17;8:594372. doi: 10.3389/fcell.2020.594372. eCollection 2020.
Our previous study found that Notch3 knockout mice exhibit defects in mammary gland development. To elucidate the underlying mechanism, tissue samples were subjected to RNA-seq, GO, and KEGG enrichment analyses and qRT-PCR validation. Of enriched pathways, chemokine signaling pathway and cytokine-cytokine receptor interaction were noticed in both Notch3/Notch3 and Notch3/Notch3 mice, in which the expression of chemokine ligand 2 (CCL2) was sharply reduced in Notch3 and Notch3 mammary gland tissues. The Mouse ENCODE transcriptome data reveal that the mammary gland fat pad exhibits a high CCL2, CCR2, and CCR4 expression, indicating that these molecules play important roles during mammary gland development. Specifically, defective mammary glands in Notch3 knockout mice could be partially rescued by CCL2 overexpression lentivirus through intraductal injection. An study showed that CCL2 overexpression promoted the proliferation, migration, and cancerous acinar formation of 4T1 cells, which could rescue the defective migration of 4T1 cells caused by Notch3 knockdown. We also found that Notch3 transcriptionally regulated the expression of CCL2 in a classical pattern. Our findings illustrated that Notch3-regulating CCL2/CCR4 axis should be an important signaling pathway for mammary gland development and should be a candidate target for breast cancer therapy.
我们之前的研究发现，Notch3基因敲除小鼠的乳腺发育存在缺陷。为了阐明其潜在机制，对组织样本进行了RNA测序、基因本体（GO）和京都基因与基因组百科全书（KEGG）富集分析以及定量逆转录聚合酶链反应（qRT-PCR）验证。在富集的通路中，Notch3基因敲除小鼠和野生型小鼠均发现趋化因子信号通路和细胞因子-细胞因子受体相互作用，其中趋化因子配体2（CCL2）在Notch3基因敲除小鼠和野生型小鼠的乳腺组织中的表达均显著降低。小鼠ENCODE转录组数据显示，乳腺脂肪垫中CCL2、CC趋化因子受体2（CCR2）和CC趋化因子受体4（CCR4）表达较高，表明这些分子在乳腺发育过程中发挥重要作用。具体而言，通过导管内注射CCL2过表达慢病毒可部分挽救Notch3基因敲除小鼠有缺陷的乳腺。一项研究表明，CCL2过表达促进了4T1细胞的增殖、迁移和癌性腺泡形成，这可以挽救由Notch3基因敲低引起的4T1细胞迁移缺陷。我们还发现，Notch3以经典模式转录调控CCL2的表达。我们的研究结果表明，Notch3调控的CCL2/CCR4轴应该是乳腺发育的重要信号通路，并且应该是乳腺癌治疗的候选靶点。
