乳腺癌耐药蛋白(Breast cancer resistance protein, BCRP), 又名ABCG2, 是ATP结合盒(ATP-binding cas-sette, ABC)转运蛋白超家族成员之一, 在肿瘤多药耐药中具有十分重要的作用。BCRP基因启动子区无TATA盒, 含CAAT盒、AP1位点、AP2位点以及CpG岛下游的多个Sp-1位点。近年来的研究发现, 转录因子孕激素受体(PR)、雌激素受体(ER)、核因子-κB (NF-κB)、缺氧诱导因子(HIF)、Nrf2、芳香烃受体(AhR)、过氧化物酶体增殖活化受体(PPAR)和KLF5等可与BCRP启动子或增强子区的特定反应元件结合进而激活BCRP的转录。促炎细胞因子、生长因子、同源盒基因MSX2、Sonic hedgehog信号通路、Notch信号通路和RAR/RXR信号通路等均参与了BCRP的转录调控。此外, 启动子甲基化和组蛋白乙酰化在BCRP转录调控尤其是药物诱导BCRP表达中发挥重要作用。文章综述了这一研究领域的进展, 着重讨论了转录因子及表观遗传学在BCRP转录调控中的作用。
Breast cancer resistance protein (BCRP), also known as ABCG2, is a member of the ATP-binding cassette (ABC) transporter superfamily, and is known to play important roles in cancer multidrug resistance. The BCRP promoter lacks a TATA-box and contains a CAAT-box, lots of AP1, AP2 sites and several putative Sp1 sites which are downstream of a putative CpG island. Several transcription factors, such as progesterone receptor (PR), estrogen receptor (ER), nuclear factor-κB (NF-κB), hypoxia-inducible factors (HIFs), nuclear factor erythroid 2-related factor 2 (Nrf2), aryl hydrocarbon receptor (AhR), peroxisome proliferator-activated receptors (PPARs) and Krüppel-like factor 5 (KLF5), have been recently shown to bind to their response elements in the promoter/enhancer to activate the transcription of BCRP. BCRP transcription can be influenced by proinflammatory cytokines, growth factors, and homeobox protein MSX2. Signaling pathways, such as Sonic hedgehog (Shh), Notch and RAR/RXR pathways, may also involve in the transcriptional regulation of BCRP. In addition, promoter methylation and histone acetylation are essential for the BCRP transcription, especially for the drug-induced BCRP expression. This paper reviews the recent research progresses in this field with an emphasis on the roles of transcription factors and epigenetics in the transcriptional regulation of BCRP.
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