Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells....Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells.BCRP physiologically functions as a part of a self-defense mechanism for the organism;it enhances elimination of toxic xenobiotic substances and harmful agents in the gut and biliary tract,as well as through the blood-brain,placental,and possibly blood-testis barriers.BCRP recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and targeted small therapeutic molecules relatively new in clinical use.Thus,BCRP expression in cancer cells directly causes MDR by active efflux of anticancer drugs.Because BCRP is also known to be a stem cell marker,its expression in cancer cells could be a manifestation of metabolic and signaling pathways that confer multiple mechanisms of drug resistance,self-renewal(stemness),and invasiveness(aggressiveness),and thereby impart a poor prognosis.Therefore,blocking BCRP-mediated active efflux may provide a therapeutic benefit for cancers.Delineating the precise molecular mechanisms for BCRP gene expression may lead to identification of a novel molecular target to modulate BCRP-mediated MDR.Current evidence suggests that BCRP gene transcription is regulated by a number of trans-acting elements including hypoxia inducible factor 1α,estrogen receptor,and peroxisome proliferator-activated receptor.Furthermore,alternative promoter usage,demethylation of the BCRP promoter,and histone modification are likely associated with drug-induced BCRP overexpression in cancer cells.Finally,PI3K/AKT signaling may play a critical role in modulating BCRP function under a variety of conditions.These biological events seem involved in a complicated manner.Untangling the events would be an essential first step to developing a method to modulate BCRP function to aid patients with cancer.This review will present a synopsis of the impact of BCRP-mediated MDR in ca展开更多
Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in s...Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in several different enteropathies, including inflammatory bowel disease. It develops through complex cell, extracellular matrix, cytokine and growth factor interactions. Distinct cell types are involved in intestinal fibrosis, such as resident mesenchymal cells (fibroblasts, myofibroblasts and smooth muscle cells) but also ECM-producing cells derived from epithelial and endothelial cells (through a process termed epithelialand endothelial-mesenchymal transition), stellate cells, pericytes, local or bone marrow-derived stem cells. The most important soluble factors that regulate the activation of these cells include cytokines, chemokines, growth factors, components of the renin-angiotensin system, angiogenic factors, peroxisome proliferator-activated receptors, mammalian target of rapamycin, and products of oxidative stress. It soon becomes clear that although inflammation is responsible for triggering the onset of the fibrotic proc-ess, it only plays a minor role in the progression of this condition, as fibrosis may advance in a self-perpetuating fashion. Definition of the cellular and molecular mechanisms involved in intestinal fibrosis may provide the key to developing new therapeutic approaches.展开更多
目的:观察黄芪葛根汤对2型糖尿病大鼠胰岛素抵抗及脂肪组织中过氧化物酶体增生物激活受体-γ(PPAR-γ)mRNA表达的影响。方法:雄性SD大鼠高脂饲料喂养4周后注射小剂量链脲佐菌素,1周后测定大鼠空腹血糖(FBG)及糖负荷2 h后血糖(2 h BG),选...目的:观察黄芪葛根汤对2型糖尿病大鼠胰岛素抵抗及脂肪组织中过氧化物酶体增生物激活受体-γ(PPAR-γ)mRNA表达的影响。方法:雄性SD大鼠高脂饲料喂养4周后注射小剂量链脲佐菌素,1周后测定大鼠空腹血糖(FBG)及糖负荷2 h后血糖(2 h BG),选择FBG正常及2 h BG≥7.8 mmol.L-1者为模型大鼠。取模型大鼠,随机分为模型对照组、罗格列酮组,黄芪葛根汤高、中、低剂量组,另设正常对照组,药物干预8周后,测定FBG,空腹胰岛素水平(FINS),血浆瘦素(Leptin),肿瘤坏死因子-α(TNF-α),计算胰岛素敏感指数(ISI)和抵抗指数(HOMA-IR),提取大网膜脂肪组织总RNA,采用逆转录PCR技术扩增PPAR-γ基因片段,检测其基因表达水平。结果:黄芪葛根汤能提高模型大鼠ISI,降低HOMA-IR指数,降低Leptin和TNF-α水平,增加PPAR-γmRNA表达。结论:黄芪葛根汤对大鼠IR具有显著的改善作用,其机制可能与降低血浆Leptin,TNF-α水平,提高脂肪组织PPAR-γmRNA表达有关。展开更多
文摘Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells.BCRP physiologically functions as a part of a self-defense mechanism for the organism;it enhances elimination of toxic xenobiotic substances and harmful agents in the gut and biliary tract,as well as through the blood-brain,placental,and possibly blood-testis barriers.BCRP recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and targeted small therapeutic molecules relatively new in clinical use.Thus,BCRP expression in cancer cells directly causes MDR by active efflux of anticancer drugs.Because BCRP is also known to be a stem cell marker,its expression in cancer cells could be a manifestation of metabolic and signaling pathways that confer multiple mechanisms of drug resistance,self-renewal(stemness),and invasiveness(aggressiveness),and thereby impart a poor prognosis.Therefore,blocking BCRP-mediated active efflux may provide a therapeutic benefit for cancers.Delineating the precise molecular mechanisms for BCRP gene expression may lead to identification of a novel molecular target to modulate BCRP-mediated MDR.Current evidence suggests that BCRP gene transcription is regulated by a number of trans-acting elements including hypoxia inducible factor 1α,estrogen receptor,and peroxisome proliferator-activated receptor.Furthermore,alternative promoter usage,demethylation of the BCRP promoter,and histone modification are likely associated with drug-induced BCRP overexpression in cancer cells.Finally,PI3K/AKT signaling may play a critical role in modulating BCRP function under a variety of conditions.These biological events seem involved in a complicated manner.Untangling the events would be an essential first step to developing a method to modulate BCRP function to aid patients with cancer.This review will present a synopsis of the impact of BCRP-mediated MDR in ca
文摘Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in several different enteropathies, including inflammatory bowel disease. It develops through complex cell, extracellular matrix, cytokine and growth factor interactions. Distinct cell types are involved in intestinal fibrosis, such as resident mesenchymal cells (fibroblasts, myofibroblasts and smooth muscle cells) but also ECM-producing cells derived from epithelial and endothelial cells (through a process termed epithelialand endothelial-mesenchymal transition), stellate cells, pericytes, local or bone marrow-derived stem cells. The most important soluble factors that regulate the activation of these cells include cytokines, chemokines, growth factors, components of the renin-angiotensin system, angiogenic factors, peroxisome proliferator-activated receptors, mammalian target of rapamycin, and products of oxidative stress. It soon becomes clear that although inflammation is responsible for triggering the onset of the fibrotic proc-ess, it only plays a minor role in the progression of this condition, as fibrosis may advance in a self-perpetuating fashion. Definition of the cellular and molecular mechanisms involved in intestinal fibrosis may provide the key to developing new therapeutic approaches.
文摘目的:观察黄芪葛根汤对2型糖尿病大鼠胰岛素抵抗及脂肪组织中过氧化物酶体增生物激活受体-γ(PPAR-γ)mRNA表达的影响。方法:雄性SD大鼠高脂饲料喂养4周后注射小剂量链脲佐菌素,1周后测定大鼠空腹血糖(FBG)及糖负荷2 h后血糖(2 h BG),选择FBG正常及2 h BG≥7.8 mmol.L-1者为模型大鼠。取模型大鼠,随机分为模型对照组、罗格列酮组,黄芪葛根汤高、中、低剂量组,另设正常对照组,药物干预8周后,测定FBG,空腹胰岛素水平(FINS),血浆瘦素(Leptin),肿瘤坏死因子-α(TNF-α),计算胰岛素敏感指数(ISI)和抵抗指数(HOMA-IR),提取大网膜脂肪组织总RNA,采用逆转录PCR技术扩增PPAR-γ基因片段,检测其基因表达水平。结果:黄芪葛根汤能提高模型大鼠ISI,降低HOMA-IR指数,降低Leptin和TNF-α水平,增加PPAR-γmRNA表达。结论:黄芪葛根汤对大鼠IR具有显著的改善作用,其机制可能与降低血浆Leptin,TNF-α水平,提高脂肪组织PPAR-γmRNA表达有关。
