The interference of human heat shock protein 90 (HSP90) in many signalling networks associated with cancer progression makes it an important drug target. In the present work, we investigated the binding ability of 9 s...The interference of human heat shock protein 90 (HSP90) in many signalling networks associated with cancer progression makes it an important drug target. In the present work, we investigated the binding ability of 9 selenoderivatives of geldanamycin (GMDSe) at the N-terminal domain of HSP90 derived from Protein Data Bank (PDB code: 1YET) based on ligand-protein docking. All selenoderivatives interacted positively with HSP90, yet the binding strength decreased when replacing monovalent oxygen in position 1 (GMDSe1) or 9 (GMDSe9). Hydrogen-bonding and lipophilic interactions between selenoderivatives and amino acid residues in the inhibitor site of HSP90 were thermodynamically the main forces driving the binding stability. Molecular electrostatic potential surfaces of the selenoderivatives showed marked non polar areas, which were probably involved in the lipophilic interactions with the hydrophobic residues of amino acids. Interestingly, the amino acid residues forming the hydrogen bonds with GMD were also involved in the hydrogen-bonding interactions with the selenoderivatives. Moreover, HSP90 interacted with the GMDSe6 and GMDSe7 selenoderivatives stronger than with GMD, while maintaining lipophilic interactions and hydrogen bonds with amino acid residues like Asp93, which are catalytically crucial for therapeutic properties of HSP90 inhibitors. This finding should guide further studies of pharmacophore properties of GMD selenoderivatives in order to explore their therapeutic properties. It is noteworthy that selenium has been suggested to reduce the risk of various types of cancers.展开更多
Objective Benzoquinone ansamycin antibiotic, geldanamycin (GA), is a new anticancer agent that could inhibit Hsp90 by occupying its NH2-terminal ATP-binding site. This study was to investigate the antitumor efficacy o...Objective Benzoquinone ansamycin antibiotic, geldanamycin (GA), is a new anticancer agent that could inhibit Hsp90 by occupying its NH2-terminal ATP-binding site. This study was to investigate the antitumor efficacy of GA on Her2/neu tyrosine kinase overexpressing human breast cancer cell line SKBr3. Methods The degradation of Her2/neu tyrosine kinase was analyzed by Western blotting, the proliferation index was determined by MTT assay, cell cycle distribution was detected by flow cytometry, Cyclin D1 mRNA transcription was measured by RT-PCR and real-time PCR, and cell motility was evaluated by the cell culture insert model. Results GA induced a dose-and a time-dependent degradation of the Her2/neu tyrosine kinase protein and concurrently, the inhibition of cancer cell proliferation. The antitumor effects mediated by GA included: GA treatment decreased the survival rates of cancer cells, and led to a dose-dependent G1 arrest. Furthermore, this antitumor effect was proved to be related to declined transcription of Cyclin D1. Concurrently, the motility of cancer cells was reduced by GA. Conclusion GA treatment could induce the degradation of Her2/neu tyrosine kinase efficiently, inhibit cancer cell proliferation and reduce motility in Her2/neu tyrosine kinase overexpressed human breast cancer cell line SKBr3.展开更多
Geldanamycin (1) had been isolated as a major compound from Streptomyces zerumbet W14;an endophyte of Zingiber zerumbet (L.) Smith. Two new geldanamycin derivatives;17-(tryptamine)-17-demethoxygeldanamycin (2) and 17...Geldanamycin (1) had been isolated as a major compound from Streptomyces zerumbet W14;an endophyte of Zingiber zerumbet (L.) Smith. Two new geldanamycin derivatives;17-(tryptamine)-17-demethoxygeldanamycin (2) and 17-(5’-methoxytryptamine)-17-demethoxygeldanamycin (3) were synthe- sized and their anti-inflammatory activity was evaluated in LPS-induced macrophage RAW 264.7 cells by investigating their effects on the inhibition of production of NO, PGE2, TNF-α, IL-1β, IL-6 and IL-10. The data obtained were consistent with the modulation of TNF-α, IL-1β, IL-6, IL-10 production by these derivatives at concentration of 1 to 5 μg/ml. A similar effect was also observed when LPS-induced NO release and PGE2 production were tested. The inhibitory effects were shown in concentration-dependent manners. From the obtained results, it was concluded that two new gelda- namycin derivatives possess anti-inflammatory activity on LPS-induced RAW 264.7 cells. They could be useful for the management of inflammatory diseases.展开更多
Mitosis-targeted anti-cancer therapies gained much attention in recent years. However, lack of tumor selectivity poses limitations to the current anti-mitotic drugs to be used as broad-spectrum anti-cancer agents. In ...Mitosis-targeted anti-cancer therapies gained much attention in recent years. However, lack of tumor selectivity poses limitations to the current anti-mitotic drugs to be used as broad-spectrum anti-cancer agents. In this study, we show that combination treatment of colcemid, an inhibitor of microtubule polymerization with geldanamycin, an inhibitor of cancer chaperone, Hsp90 irreversibly targets mitosis through mitotic kinase bubR1 stabilization. When the individual and combination drugs treatments were tested against tumor cells (IMR-32 and HeLa) and non-tumor cells (SRA01), the combination treatment showed significant increase in cytotoxicity only in tumor cells followed by G2/M cell cycle block. The IMR-32 cells showed enhanced cytotoxicity in response to combination treatments, compared to HeLa cells. Further studies revealed that the G2/M arrest in IMR-32 correlates with both increased bubR1 nuclear localization and metaphase arrest. The siRNA knockdown of bubR1 has decreased tumor cell response to geldanamycin suggesting Hsp90-dependent regulation of bubR1. The combination treatment also showed inactivation of non-canonical β-catenin signaling suggesting inhibition of cancer growth. In addition, the combination treatment has significantly affected the distribution and functions of bubR1 downstream mitotic kinases such as aurks and plk1 indicating the combinatorial attack of combination treatment. In conclusion, we demonstrate that colcemid and GA combination treatment compromises the division potential of tumor cells interfering with the mitosis through bubR1 kinase.展开更多
OBJECTIVE Geldanamycin,a natural product of Streptomyces geldanus,binds the heat shock protein 90(Hsp90),a cell chaperone protein that interacts with Bcl-2.In this study,we investigated whether geldanamycin(GA)inhibit...OBJECTIVE Geldanamycin,a natural product of Streptomyces geldanus,binds the heat shock protein 90(Hsp90),a cell chaperone protein that interacts with Bcl-2.In this study,we investigated whether geldanamycin(GA)inhibits proliferation of HeLa cells through induction of apoptosis by decreasing the level of Bcl-2 expression. METHODS HeLa cells,a human cervical cell line,were cultured in vitro and treated with different concentrations of GA(0,0.02,0.2, 2,10μmol/L)for 24 h.or were treated for different lengths of time at a GA concentration of 10μmol/L.Proliferation of the cells was analyzed by an MTT assay,and cell apoptosis was determined by staining the cells with annexin V.In addition,cellular mRNA levels for Bcl-2 and Hsp90 were determined by the semiquantitative polymerase chain reaction(PCR),and the levels of Bcl-2 and Hsp90 protein expression were determined by Western blots. RESULTS Treatment of cells with GA was found to inhibit HeLa cell proliferation in a concentration and time-dependent manner.The inhibition was a result of increased cellular apoptotic levels.Further analyses showed that while the mRNA and protein expression levels of Hsp90 were not affected,GA treatment significantly reduced the level of Bcl-2 mRNA and protein expression in a concentration-dependent manner that correlated with the observed inhibition of cell proliferation. CONCLUSION GA can inhibit proliferation and increase apoptosis of HeLa cells by decreasing the transcription and expression of an anti-apoptotic gene bcl-2,probably through interaction and functional inhibition of Hsp90.展开更多
Heat shock protein 90(Hsp90) is an appealing anticancer drug target that provoked a tremendous wave of investigations. Geldanamycin(GA) is the first identified Hsp90 inhibitor that exhibited potent anticancer activity...Heat shock protein 90(Hsp90) is an appealing anticancer drug target that provoked a tremendous wave of investigations. Geldanamycin(GA) is the first identified Hsp90 inhibitor that exhibited potent anticancer activity, but the off-target toxicity associated with the benzoquinone moiety hampered its clinical application. Until now, structure optimization of GA is still in need to fully exploit the therapeutic value of Hsp90. Due to the structural complexity and synthetic challenge of this compound family, conventional optimization is bound to be costly but high efficiency is expected to be reachable by combining the art of rational design and total synthesis. Described in this paper is our first attempt at this approach aiming at rational modification of the C6-position of GA. The binding affinities towards Hsp90 of compound 1(C6-ethyl) and 2(C6-methyl) were designed and predicted by using Discovery Studio. These compounds were synthesized and further subjected to a thorough in vitro biological evaluation. We found that compounds1 and 2 bind to Hsp90 protein with the IC_(50) of 34.26 nmol/L and 163.7 nmol/L, respectively. Both compounds showed broad-spectrum antitumor effects. Replacing by ethyl, compound 1 exhibited more potent bioactivity than positive control GA, such as in G2/M cell cycle arrest, cell apoptosis and client proteins degradations. The results firstly indicated that the docking study is able to provide a precise prediction of Hsp90 affinities of GA analogues, and the C6 substituent of GA is not erasable without affecting its biological activity.展开更多
从吸水链霉菌17997中克隆了格尔德霉素(Geldanamycin,Gdm)生物合成酶基因簇,通过生物信息学分析发现两个LAL(Large ATP-bindingregulators of the LuxR family)家族的调控基因gdmRI和gdmRII,基因阻断和基因回复实验证实这两个基因产物...从吸水链霉菌17997中克隆了格尔德霉素(Geldanamycin,Gdm)生物合成酶基因簇,通过生物信息学分析发现两个LAL(Large ATP-bindingregulators of the LuxR family)家族的调控基因gdmRI和gdmRII,基因阻断和基因回复实验证实这两个基因产物都正调控Gdm的生物合成。展开更多
文摘The interference of human heat shock protein 90 (HSP90) in many signalling networks associated with cancer progression makes it an important drug target. In the present work, we investigated the binding ability of 9 selenoderivatives of geldanamycin (GMDSe) at the N-terminal domain of HSP90 derived from Protein Data Bank (PDB code: 1YET) based on ligand-protein docking. All selenoderivatives interacted positively with HSP90, yet the binding strength decreased when replacing monovalent oxygen in position 1 (GMDSe1) or 9 (GMDSe9). Hydrogen-bonding and lipophilic interactions between selenoderivatives and amino acid residues in the inhibitor site of HSP90 were thermodynamically the main forces driving the binding stability. Molecular electrostatic potential surfaces of the selenoderivatives showed marked non polar areas, which were probably involved in the lipophilic interactions with the hydrophobic residues of amino acids. Interestingly, the amino acid residues forming the hydrogen bonds with GMD were also involved in the hydrogen-bonding interactions with the selenoderivatives. Moreover, HSP90 interacted with the GMDSe6 and GMDSe7 selenoderivatives stronger than with GMD, while maintaining lipophilic interactions and hydrogen bonds with amino acid residues like Asp93, which are catalytically crucial for therapeutic properties of HSP90 inhibitors. This finding should guide further studies of pharmacophore properties of GMD selenoderivatives in order to explore their therapeutic properties. It is noteworthy that selenium has been suggested to reduce the risk of various types of cancers.
基金supported by Foundation of Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University) Ministry of Education (No.KFJJ-2005-05)
文摘Objective Benzoquinone ansamycin antibiotic, geldanamycin (GA), is a new anticancer agent that could inhibit Hsp90 by occupying its NH2-terminal ATP-binding site. This study was to investigate the antitumor efficacy of GA on Her2/neu tyrosine kinase overexpressing human breast cancer cell line SKBr3. Methods The degradation of Her2/neu tyrosine kinase was analyzed by Western blotting, the proliferation index was determined by MTT assay, cell cycle distribution was detected by flow cytometry, Cyclin D1 mRNA transcription was measured by RT-PCR and real-time PCR, and cell motility was evaluated by the cell culture insert model. Results GA induced a dose-and a time-dependent degradation of the Her2/neu tyrosine kinase protein and concurrently, the inhibition of cancer cell proliferation. The antitumor effects mediated by GA included: GA treatment decreased the survival rates of cancer cells, and led to a dose-dependent G1 arrest. Furthermore, this antitumor effect was proved to be related to declined transcription of Cyclin D1. Concurrently, the motility of cancer cells was reduced by GA. Conclusion GA treatment could induce the degradation of Her2/neu tyrosine kinase efficiently, inhibit cancer cell proliferation and reduce motility in Her2/neu tyrosine kinase overexpressed human breast cancer cell line SKBr3.
文摘Geldanamycin (1) had been isolated as a major compound from Streptomyces zerumbet W14;an endophyte of Zingiber zerumbet (L.) Smith. Two new geldanamycin derivatives;17-(tryptamine)-17-demethoxygeldanamycin (2) and 17-(5’-methoxytryptamine)-17-demethoxygeldanamycin (3) were synthe- sized and their anti-inflammatory activity was evaluated in LPS-induced macrophage RAW 264.7 cells by investigating their effects on the inhibition of production of NO, PGE2, TNF-α, IL-1β, IL-6 and IL-10. The data obtained were consistent with the modulation of TNF-α, IL-1β, IL-6, IL-10 production by these derivatives at concentration of 1 to 5 μg/ml. A similar effect was also observed when LPS-induced NO release and PGE2 production were tested. The inhibitory effects were shown in concentration-dependent manners. From the obtained results, it was concluded that two new gelda- namycin derivatives possess anti-inflammatory activity on LPS-induced RAW 264.7 cells. They could be useful for the management of inflammatory diseases.
文摘Mitosis-targeted anti-cancer therapies gained much attention in recent years. However, lack of tumor selectivity poses limitations to the current anti-mitotic drugs to be used as broad-spectrum anti-cancer agents. In this study, we show that combination treatment of colcemid, an inhibitor of microtubule polymerization with geldanamycin, an inhibitor of cancer chaperone, Hsp90 irreversibly targets mitosis through mitotic kinase bubR1 stabilization. When the individual and combination drugs treatments were tested against tumor cells (IMR-32 and HeLa) and non-tumor cells (SRA01), the combination treatment showed significant increase in cytotoxicity only in tumor cells followed by G2/M cell cycle block. The IMR-32 cells showed enhanced cytotoxicity in response to combination treatments, compared to HeLa cells. Further studies revealed that the G2/M arrest in IMR-32 correlates with both increased bubR1 nuclear localization and metaphase arrest. The siRNA knockdown of bubR1 has decreased tumor cell response to geldanamycin suggesting Hsp90-dependent regulation of bubR1. The combination treatment also showed inactivation of non-canonical β-catenin signaling suggesting inhibition of cancer growth. In addition, the combination treatment has significantly affected the distribution and functions of bubR1 downstream mitotic kinases such as aurks and plk1 indicating the combinatorial attack of combination treatment. In conclusion, we demonstrate that colcemid and GA combination treatment compromises the division potential of tumor cells interfering with the mitosis through bubR1 kinase.
文摘OBJECTIVE Geldanamycin,a natural product of Streptomyces geldanus,binds the heat shock protein 90(Hsp90),a cell chaperone protein that interacts with Bcl-2.In this study,we investigated whether geldanamycin(GA)inhibits proliferation of HeLa cells through induction of apoptosis by decreasing the level of Bcl-2 expression. METHODS HeLa cells,a human cervical cell line,were cultured in vitro and treated with different concentrations of GA(0,0.02,0.2, 2,10μmol/L)for 24 h.or were treated for different lengths of time at a GA concentration of 10μmol/L.Proliferation of the cells was analyzed by an MTT assay,and cell apoptosis was determined by staining the cells with annexin V.In addition,cellular mRNA levels for Bcl-2 and Hsp90 were determined by the semiquantitative polymerase chain reaction(PCR),and the levels of Bcl-2 and Hsp90 protein expression were determined by Western blots. RESULTS Treatment of cells with GA was found to inhibit HeLa cell proliferation in a concentration and time-dependent manner.The inhibition was a result of increased cellular apoptotic levels.Further analyses showed that while the mRNA and protein expression levels of Hsp90 were not affected,GA treatment significantly reduced the level of Bcl-2 mRNA and protein expression in a concentration-dependent manner that correlated with the observed inhibition of cell proliferation. CONCLUSION GA can inhibit proliferation and increase apoptosis of HeLa cells by decreasing the transcription and expression of an anti-apoptotic gene bcl-2,probably through interaction and functional inhibition of Hsp90.
基金supported by the CAMS Innovation Fund for Medical Sciences (Nos. CIFMS 2016-I2M-3–009 and CIFMS 2017I2M-3–011)the National Natural Science Foundation of China (No. 21272279)。
文摘Heat shock protein 90(Hsp90) is an appealing anticancer drug target that provoked a tremendous wave of investigations. Geldanamycin(GA) is the first identified Hsp90 inhibitor that exhibited potent anticancer activity, but the off-target toxicity associated with the benzoquinone moiety hampered its clinical application. Until now, structure optimization of GA is still in need to fully exploit the therapeutic value of Hsp90. Due to the structural complexity and synthetic challenge of this compound family, conventional optimization is bound to be costly but high efficiency is expected to be reachable by combining the art of rational design and total synthesis. Described in this paper is our first attempt at this approach aiming at rational modification of the C6-position of GA. The binding affinities towards Hsp90 of compound 1(C6-ethyl) and 2(C6-methyl) were designed and predicted by using Discovery Studio. These compounds were synthesized and further subjected to a thorough in vitro biological evaluation. We found that compounds1 and 2 bind to Hsp90 protein with the IC_(50) of 34.26 nmol/L and 163.7 nmol/L, respectively. Both compounds showed broad-spectrum antitumor effects. Replacing by ethyl, compound 1 exhibited more potent bioactivity than positive control GA, such as in G2/M cell cycle arrest, cell apoptosis and client proteins degradations. The results firstly indicated that the docking study is able to provide a precise prediction of Hsp90 affinities of GA analogues, and the C6 substituent of GA is not erasable without affecting its biological activity.
文摘从吸水链霉菌17997中克隆了格尔德霉素(Geldanamycin,Gdm)生物合成酶基因簇,通过生物信息学分析发现两个LAL(Large ATP-bindingregulators of the LuxR family)家族的调控基因gdmRI和gdmRII,基因阻断和基因回复实验证实这两个基因产物都正调控Gdm的生物合成。
