Chemotherapy and chemoprevention have been two of the most important means to control cancer incidence and mortality, and the cellular defensive machinery against oxidative/electrophilic stresses plays significant rol...Chemotherapy and chemoprevention have been two of the most important means to control cancer incidence and mortality, and the cellular defensive machinery against oxidative/electrophilic stresses plays significant roles in both means. This defensive system is composed of cytoprotective enzymes that metabolize and eliminate oxidative/electrophitic species. The transcription factor nuclear factor erythroid 2-related factor 2 （Nrf2） controls the basal and inducible expression of many cytoprotective genes, and plays a pivotal role in coordinating cellular defensive responses. Under basal conditions, the activity of Nrf2 is inhibited by binding to Kelch-like ECH-associated protein 1 （Keap 1）, which is capable of sensing oxidative/electrophilic signals. Upon oxidative/electrophilic stresses, the binding of Nrf2 to Keapl is disrupted, leading to activation of Nrf2 and induction of cytoprotective enzymes. Thus, Nrf2 has emerged as an important target of chemopreventive drugs. However, activation of Nrf2 could lead to very different outcomes depending on the cellular context. The indiscriminative protective effects of Nrf2 lead to its undesired functions in carcinogenesis and chemoresistance of cancer cells. Activation of Nrf2 provides neoplastic cells with growth advantages and protects cancer cells from chemotherapeutic drugs, resulting in poor clinical outcomes. In this means, inhibitors of Nrf2 signaling can enhance the efficacy of chemotherapeutic drugs and deserve further development. A better understanding of the regulation and functions of Nrf2 would be helpful for researches in both chemoprevention and chemotherapy of cancer.展开更多
Nuclear factor erythroid 2-related factor 2 （Nrf2） controls the expression of a wide array of antioxidant response element （ARE）-driven genes, which are involved in stress response and metabolism regulation. The r...Nuclear factor erythroid 2-related factor 2 （Nrf2） controls the expression of a wide array of antioxidant response element （ARE）-driven genes, which are involved in stress response and metabolism regulation. The role of Nrf2/ARE signaling in resistances of cancer cells to radiotherapy and chemotherapy has been widely accepted. However, much less is known about the relevance of Nrf2 to chemotherapy-associated toxicities, such as hepatotoxicity. In the present study, nine chemotherapeutic agents were firstly tested in embryonic fibroblasts （MEFs） and hepatocytes isolated from Nrf2 deficient or wild-type mice. The results indicate that the cytotoxicity of oxaliplatin in hepatocytes was significantly higher than that in MEFs and enhanced by Nrf2 deficiency. Furthermore, oxaliplatin treatment caused more pronounced steatosis and severer liver injury in Nrf2-/- mice compared with wild-type counterparts, as evidenced by dramatically elevated serum transaminase and bilirubin, increased accumulation of fat, inflammatory infiltration and blood congestion. The increased hepatotoxicity in Nrf2 deficient mice was possibly caused by decreased expression of antioxidant genes and glutathione depletion. Our results demonstrated that oxaliplatin-induced hepatotoxicity was significantly impacted by Nrf2 status, therefore Nrf2 could potentially serve as a biomarker to predict or a target to prevent hepatotoxicity of oxaliplatin.展开更多
经口吸入制剂(orally inhaled drug products,OIDPs)是慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)和哮喘的药物治疗指南推荐的首选药物,存在着临床需求未满足的现状。药效动力学-生物等效性研究(pharmacodynamics-b...经口吸入制剂(orally inhaled drug products,OIDPs)是慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)和哮喘的药物治疗指南推荐的首选药物,存在着临床需求未满足的现状。药效动力学-生物等效性研究(pharmacodynamics-bioequivalence,PD-BE)是各国指导原则推荐评价OIDPs生物等效性的重要研究方法,它有效地弥补了体外研究、药代动力学-生物等效性研究(pharmacokinetics-bioequivalence,PK-BE)在评价仿制药与原研药疗效和安全一致性上的不足。OIDPs的PD-BE有两种研究方法,分别采用舒张试验模型以及激发试验模型,不同研究方法选用的药效评价指标不同,较常用指标包括:第一秒用力呼气容积(forced expiratory volume in the first second,FEV_(1))、比气道传导率(specific airway conductance,sGaw)、外周气道阻力(R_(5-20))以及激发剂浓度/剂量(PC_(20)/PD_(20))。以FEV_(1)为药效评价指标的PD-BE研究也是美国食品药品监督管理局(Food and Drug Administration,FDA)、欧洲药品管理局(European Medicines Agency,EMA)以及中国国家药品监督管理局(National Medical Products Administration,NMPA)的指导原则所推荐、研究者所广泛认可的评价方法。在此类PD-BE研究中,不同OIDPs药物的试验方案在试验设计、试验数据处理、等效性评价标准等方面较为一致,同时在目标人群选择、单/多次给药、给药剂量、FEV_(1)采集点设计等方面存在细节上的不同。本文结合了各国指导原则,就近五年来发表的OIDPs的PD-BE相关研究,对PD-BE研究在OIDPs的生物等效性评价中的进展进行综述,以期对经口吸入制剂的PD-BE研究提供重要理论信息。展开更多
As a first line anti-diabetes drug, the molecular mechanisms by which metformin exerts its pharmacological activities are still under extensive investigations. The Nrf2 signaling plays a crucial role in protecting cel...As a first line anti-diabetes drug, the molecular mechanisms by which metformin exerts its pharmacological activities are still under extensive investigations. The Nrf2 signaling plays a crucial role in protecting cells from oxidative damages, and has emerged as a promising target for treatment of diabetes and related complexes in recent years. In the present study, the effect of metformin on Nrf2 signaling was tested in vitro and in vivo, and the possible mechanism was explored. Metformin activated AMPK and Nrf2 signaling and induced the expression of antioxidant genes NQO1 and y-GCSm in C2C12 mouse myoblast cells in a similar concentration- and time-dependent manner. Moreover, overexpression of AMPK significantly elevated the basal and metformin-induced ARE-driven luciferase reporter activities, suggesting the involvement of AMPK in metformin-activated Nrf2 signaling. Finally, metformin activated Nrf2 signaling and induced the expression of antioxidant genes such as HO-1 and SOD, and resulted in increased GSH level in mouse liver and skeletal muscle tissues. Take together, our results clearly demonstrated that metformin activated Nrf2 signaling and enhanced the tissue antioxidant capacity, and provide a new molecular mechanism of action of metformin.展开更多
Hematological toxicity （bone marrow suppression） is the most common dose-limiting adverse effect of chemotherapies. The nuclear factor erythroid 2-related factor 2 （Nrf2） is a pivotal coordinator of cellular defen...Hematological toxicity （bone marrow suppression） is the most common dose-limiting adverse effect of chemotherapies. The nuclear factor erythroid 2-related factor 2 （Nrf2） is a pivotal coordinator of cellular defensive responses against chemical insults in many tissues including bone marrow. In the present study, the effects of tert-butylhydroquinone （tBHQ） on the expression of Nrf2-regulated genes in peripheral blood cells and cyclophosphamide （CTX）-induced hematotoxicity in mice were investigated. CTX induced apoptosis of peripheral blood nucleated cells and leukopenia in mice, accompanied by mobilization of bone marrow hematopoietic cells, tBHQ treatment induced the expression of Nrf2-regulated genes such as heine oxygenase 1 （HO1） and glutamate-cysteine ligase catalytic subtmit （GCLC） in RAW264.7 mouse macrophage cells and peripheral blood cells both in vitro and in vivo. Interestingly, pretreatment with tBHQ alleviated CTX-induced mouse peripheral blood cell apoptosis and leukopenia in vivo, indicating possible involvement of Nrf2 in the protection against CTX-induced hematotoxicity. This study provides new information on the chemotherapy-induced hematotoxicity, and suggests Nrf2 could serve as a target for the development of chemoprotectants against hematotoxicity.展开更多
基金Ministry of Science and Technology of China (The National Basic research Program of China, Grant No. 2009CB526509)supported by Peking University Health Science Center (bmu2009138-121)
文摘Chemotherapy and chemoprevention have been two of the most important means to control cancer incidence and mortality, and the cellular defensive machinery against oxidative/electrophilic stresses plays significant roles in both means. This defensive system is composed of cytoprotective enzymes that metabolize and eliminate oxidative/electrophitic species. The transcription factor nuclear factor erythroid 2-related factor 2 （Nrf2） controls the basal and inducible expression of many cytoprotective genes, and plays a pivotal role in coordinating cellular defensive responses. Under basal conditions, the activity of Nrf2 is inhibited by binding to Kelch-like ECH-associated protein 1 （Keap 1）, which is capable of sensing oxidative/electrophilic signals. Upon oxidative/electrophilic stresses, the binding of Nrf2 to Keapl is disrupted, leading to activation of Nrf2 and induction of cytoprotective enzymes. Thus, Nrf2 has emerged as an important target of chemopreventive drugs. However, activation of Nrf2 could lead to very different outcomes depending on the cellular context. The indiscriminative protective effects of Nrf2 lead to its undesired functions in carcinogenesis and chemoresistance of cancer cells. Activation of Nrf2 provides neoplastic cells with growth advantages and protects cancer cells from chemotherapeutic drugs, resulting in poor clinical outcomes. In this means, inhibitors of Nrf2 signaling can enhance the efficacy of chemotherapeutic drugs and deserve further development. A better understanding of the regulation and functions of Nrf2 would be helpful for researches in both chemoprevention and chemotherapy of cancer.
基金National Natural Science Foundation of China(Grant No.81272468,81372266,91429305 and 21001011)WU JIEPING Medical Foundation(Grant No.320.6750.12196)
文摘Nuclear factor erythroid 2-related factor 2 （Nrf2） controls the expression of a wide array of antioxidant response element （ARE）-driven genes, which are involved in stress response and metabolism regulation. The role of Nrf2/ARE signaling in resistances of cancer cells to radiotherapy and chemotherapy has been widely accepted. However, much less is known about the relevance of Nrf2 to chemotherapy-associated toxicities, such as hepatotoxicity. In the present study, nine chemotherapeutic agents were firstly tested in embryonic fibroblasts （MEFs） and hepatocytes isolated from Nrf2 deficient or wild-type mice. The results indicate that the cytotoxicity of oxaliplatin in hepatocytes was significantly higher than that in MEFs and enhanced by Nrf2 deficiency. Furthermore, oxaliplatin treatment caused more pronounced steatosis and severer liver injury in Nrf2-/- mice compared with wild-type counterparts, as evidenced by dramatically elevated serum transaminase and bilirubin, increased accumulation of fat, inflammatory infiltration and blood congestion. The increased hepatotoxicity in Nrf2 deficient mice was possibly caused by decreased expression of antioxidant genes and glutathione depletion. Our results demonstrated that oxaliplatin-induced hepatotoxicity was significantly impacted by Nrf2 status, therefore Nrf2 could potentially serve as a biomarker to predict or a target to prevent hepatotoxicity of oxaliplatin.
文摘经口吸入制剂(orally inhaled drug products,OIDPs)是慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)和哮喘的药物治疗指南推荐的首选药物,存在着临床需求未满足的现状。药效动力学-生物等效性研究(pharmacodynamics-bioequivalence,PD-BE)是各国指导原则推荐评价OIDPs生物等效性的重要研究方法,它有效地弥补了体外研究、药代动力学-生物等效性研究(pharmacokinetics-bioequivalence,PK-BE)在评价仿制药与原研药疗效和安全一致性上的不足。OIDPs的PD-BE有两种研究方法,分别采用舒张试验模型以及激发试验模型,不同研究方法选用的药效评价指标不同,较常用指标包括:第一秒用力呼气容积(forced expiratory volume in the first second,FEV_(1))、比气道传导率(specific airway conductance,sGaw)、外周气道阻力(R_(5-20))以及激发剂浓度/剂量(PC_(20)/PD_(20))。以FEV_(1)为药效评价指标的PD-BE研究也是美国食品药品监督管理局(Food and Drug Administration,FDA)、欧洲药品管理局(European Medicines Agency,EMA)以及中国国家药品监督管理局(National Medical Products Administration,NMPA)的指导原则所推荐、研究者所广泛认可的评价方法。在此类PD-BE研究中,不同OIDPs药物的试验方案在试验设计、试验数据处理、等效性评价标准等方面较为一致,同时在目标人群选择、单/多次给药、给药剂量、FEV_(1)采集点设计等方面存在细节上的不同。本文结合了各国指导原则,就近五年来发表的OIDPs的PD-BE相关研究,对PD-BE研究在OIDPs的生物等效性评价中的进展进行综述,以期对经口吸入制剂的PD-BE研究提供重要理论信息。
基金National Natural Science Foundation(Grant No.812 72468 and 81472657)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education
文摘As a first line anti-diabetes drug, the molecular mechanisms by which metformin exerts its pharmacological activities are still under extensive investigations. The Nrf2 signaling plays a crucial role in protecting cells from oxidative damages, and has emerged as a promising target for treatment of diabetes and related complexes in recent years. In the present study, the effect of metformin on Nrf2 signaling was tested in vitro and in vivo, and the possible mechanism was explored. Metformin activated AMPK and Nrf2 signaling and induced the expression of antioxidant genes NQO1 and y-GCSm in C2C12 mouse myoblast cells in a similar concentration- and time-dependent manner. Moreover, overexpression of AMPK significantly elevated the basal and metformin-induced ARE-driven luciferase reporter activities, suggesting the involvement of AMPK in metformin-activated Nrf2 signaling. Finally, metformin activated Nrf2 signaling and induced the expression of antioxidant genes such as HO-1 and SOD, and resulted in increased GSH level in mouse liver and skeletal muscle tissues. Take together, our results clearly demonstrated that metformin activated Nrf2 signaling and enhanced the tissue antioxidant capacity, and provide a new molecular mechanism of action of metformin.
基金National Natural Science Foundation(Grant No.81272468 and 21001011)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education
文摘Hematological toxicity （bone marrow suppression） is the most common dose-limiting adverse effect of chemotherapies. The nuclear factor erythroid 2-related factor 2 （Nrf2） is a pivotal coordinator of cellular defensive responses against chemical insults in many tissues including bone marrow. In the present study, the effects of tert-butylhydroquinone （tBHQ） on the expression of Nrf2-regulated genes in peripheral blood cells and cyclophosphamide （CTX）-induced hematotoxicity in mice were investigated. CTX induced apoptosis of peripheral blood nucleated cells and leukopenia in mice, accompanied by mobilization of bone marrow hematopoietic cells, tBHQ treatment induced the expression of Nrf2-regulated genes such as heine oxygenase 1 （HO1） and glutamate-cysteine ligase catalytic subtmit （GCLC） in RAW264.7 mouse macrophage cells and peripheral blood cells both in vitro and in vivo. Interestingly, pretreatment with tBHQ alleviated CTX-induced mouse peripheral blood cell apoptosis and leukopenia in vivo, indicating possible involvement of Nrf2 in the protection against CTX-induced hematotoxicity. This study provides new information on the chemotherapy-induced hematotoxicity, and suggests Nrf2 could serve as a target for the development of chemoprotectants against hematotoxicity.
