CREB-binding protein （CBP） and its homologue p300 are transcriptional co-activators of various sequence-specific transcription factors that are involved in a wide array of cellular activities, such as DNA repair, ce...CREB-binding protein （CBP） and its homologue p300 are transcriptional co-activators of various sequence-specific transcription factors that are involved in a wide array of cellular activities, such as DNA repair, cell growth, differentia- tion and apoptosis. Several studies have suggested that CBP and p300 might be considered as tumour suppressors, with their prominent role being the cross-coupling of distinct gene expression patterns in response to various stimuli. They exert their actions mainly via acetylation of histones and other regulatory proteins （e.g. p53）. A major paradox in CBP/ p300 function is that they seem capable of contributing to various opposed cellular processes. Respiratory epithelium tumorigenesis represents a complex process of multi-step accumulations of a gamut of genetic and epigenetic aberrations. Transcription modulation through the alternate formation of activating and repressive complexes is the ultimate converging point of these derangements, and CBP/p300 represents key participants in this interplay. Thus, illumination of their molecular actions and interactions could reveal new potential targets for pharmacological interventions in respiratory epithelium carcinogenesis.展开更多
This paper reviews the distinctive roles played by the transcriptional coactivators CREB-binding protein(CBP) and p300 in Wnt/β-catenin signaling and cell physiology in colorectal cancer(CRC). Specifically, we focus ...This paper reviews the distinctive roles played by the transcriptional coactivators CREB-binding protein(CBP) and p300 in Wnt/β-catenin signaling and cell physiology in colorectal cancer(CRC). Specifically, we focus on the effects of CBP- and p300-mediated Wnt activity on(1) neoplastic progression;(2) the activities of butyrate, a breakdown product of dietary fiber, on cell signaling and colonic cell physiology;(3) the development of resistance to histone deacetylase inhibitors(HDACis), including butyrate and synthetic HDACis, in colonic cells; and(4) the physiology and number of cancer stem cells. Mutations of the Wnt/β-catenin signaling pathway initiate the majority of CRC cases, and we have shown that hyperactivation of this pathway by butyrate and other HDACis promotes CRC cell apoptosis. This activity by butyrate may in part explain the preventive action of fiber against CRC. However, individuals with a high-fiber diet may still develop neoplasia; therefore, resistance to the chemopreventive action of butyrate likely contributes to CRC. CBP or p300 may modify the ability of butyrate to influence colonic cell physiology since the two transcriptional coactivators affect Wnt signaling, and likely, its hyperactivation by butyrate. Also, CBP and p300 likely affect colonic tumorigenesis, as well as stem cell pluripotency. Improvement of CRC prevention and therapy requires a better understanding of the alterations in Wnt signaling and gene expression that underlie neoplastic progression, stem cell fate, and the development of resistance to butyrate and clinically relevant HDACis. Detailed knowledge of how CBP- and p300 modulate colonic cell physiology may lead to new approaches for anti-CRC prevention and therapeutics, particularly with respect to combinatorial therapy of CBP/p300 inhibitors with HDACis.展开更多
目的探讨槲皮素抑制前列腺癌的作用机制。方法应用蛋白印迹技术检查槲皮素(quercetin)对雄激素受体(androgen receptor,AR)的辅调节因子c-Jun和cAMP应答元件结合蛋白的结合蛋白[cAMP response elem entb ind ing prote in(CREB)-b ind i...目的探讨槲皮素抑制前列腺癌的作用机制。方法应用蛋白印迹技术检查槲皮素(quercetin)对雄激素受体(androgen receptor,AR)的辅调节因子c-Jun和cAMP应答元件结合蛋白的结合蛋白[cAMP response elem entb ind ing prote in(CREB)-b ind ing prote in,CBP]蛋白表达的影响;利用细胞转染技术检测c-Jun和CBP对AR功能的影响;免疫沉淀技术检验c-Jun与AR的蛋白-蛋白相互作用。结果槲皮素能够明显诱导c-Jun的高表达,高表达的c-Jun能够抑制AR的功能。槲皮素对CBP的蛋白表达水平无明显影响,而增加CBP的表达并不能逆转槲皮素对AR功能的抑制作用。免疫沉淀结果表明,c-Jun与AR存在蛋白-蛋白相互作用。结论槲皮素抑制前列腺癌的机制可能是通过c-Jun与AR的蛋白相互作用,而不是通过c-Jun竞争结合AR的辅激活因子CBP来实现的。展开更多
文摘CREB-binding protein （CBP） and its homologue p300 are transcriptional co-activators of various sequence-specific transcription factors that are involved in a wide array of cellular activities, such as DNA repair, cell growth, differentia- tion and apoptosis. Several studies have suggested that CBP and p300 might be considered as tumour suppressors, with their prominent role being the cross-coupling of distinct gene expression patterns in response to various stimuli. They exert their actions mainly via acetylation of histones and other regulatory proteins （e.g. p53）. A major paradox in CBP/ p300 function is that they seem capable of contributing to various opposed cellular processes. Respiratory epithelium tumorigenesis represents a complex process of multi-step accumulations of a gamut of genetic and epigenetic aberrations. Transcription modulation through the alternate formation of activating and repressive complexes is the ultimate converging point of these derangements, and CBP/p300 represents key participants in this interplay. Thus, illumination of their molecular actions and interactions could reveal new potential targets for pharmacological interventions in respiratory epithelium carcinogenesis.
基金Supported by National Institutes of Health(Bethesda,MD)National Cancer Institute,No.1R15CA149589-01
文摘This paper reviews the distinctive roles played by the transcriptional coactivators CREB-binding protein(CBP) and p300 in Wnt/β-catenin signaling and cell physiology in colorectal cancer(CRC). Specifically, we focus on the effects of CBP- and p300-mediated Wnt activity on(1) neoplastic progression;(2) the activities of butyrate, a breakdown product of dietary fiber, on cell signaling and colonic cell physiology;(3) the development of resistance to histone deacetylase inhibitors(HDACis), including butyrate and synthetic HDACis, in colonic cells; and(4) the physiology and number of cancer stem cells. Mutations of the Wnt/β-catenin signaling pathway initiate the majority of CRC cases, and we have shown that hyperactivation of this pathway by butyrate and other HDACis promotes CRC cell apoptosis. This activity by butyrate may in part explain the preventive action of fiber against CRC. However, individuals with a high-fiber diet may still develop neoplasia; therefore, resistance to the chemopreventive action of butyrate likely contributes to CRC. CBP or p300 may modify the ability of butyrate to influence colonic cell physiology since the two transcriptional coactivators affect Wnt signaling, and likely, its hyperactivation by butyrate. Also, CBP and p300 likely affect colonic tumorigenesis, as well as stem cell pluripotency. Improvement of CRC prevention and therapy requires a better understanding of the alterations in Wnt signaling and gene expression that underlie neoplastic progression, stem cell fate, and the development of resistance to butyrate and clinically relevant HDACis. Detailed knowledge of how CBP- and p300 modulate colonic cell physiology may lead to new approaches for anti-CRC prevention and therapeutics, particularly with respect to combinatorial therapy of CBP/p300 inhibitors with HDACis.
文摘目的探讨槲皮素抑制前列腺癌的作用机制。方法应用蛋白印迹技术检查槲皮素(quercetin)对雄激素受体(androgen receptor,AR)的辅调节因子c-Jun和cAMP应答元件结合蛋白的结合蛋白[cAMP response elem entb ind ing prote in(CREB)-b ind ing prote in,CBP]蛋白表达的影响;利用细胞转染技术检测c-Jun和CBP对AR功能的影响;免疫沉淀技术检验c-Jun与AR的蛋白-蛋白相互作用。结果槲皮素能够明显诱导c-Jun的高表达,高表达的c-Jun能够抑制AR的功能。槲皮素对CBP的蛋白表达水平无明显影响,而增加CBP的表达并不能逆转槲皮素对AR功能的抑制作用。免疫沉淀结果表明,c-Jun与AR存在蛋白-蛋白相互作用。结论槲皮素抑制前列腺癌的机制可能是通过c-Jun与AR的蛋白相互作用,而不是通过c-Jun竞争结合AR的辅激活因子CBP来实现的。
