Heat-shock protein 90 augments neuronal nitric oxide synthase activity by enhancing Ca2+/calmodulin binding

2001 ◽  
Vol 355 (2) ◽  
pp. 357-360 ◽  
Author(s):  
Yao SONG ◽  
Jay L. ZWEIER ◽  
Yong XIA
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 90 ◽  
Maximal Activity ◽  
Dependent Manner ◽  
Calmodulin Binding ◽  
Catalytic Function ◽  
Oxide Synthase

Heat-shock protein 90 (hsp90) has been shown to facilitate neuronal NO synthase (nNOS, type 1) activity in vivo. But the direct effect of hsp90 on purified nNOS has not been determined yet. Moreover, the mechanism underlying the action of hsp90 is not known. nNOS activity is primarily initiated and regulated by the binding of Ca2+/calmodulin (CaM). Therefore, we explored whether hsp90 modulates nNOS activity by affecting CaM binding. Recombinant rat nNOS was purified from the stably transfected cells by affinity chromatography. hsp90 increased nNOS activity in a dose-dependent manner with an EC50 of 24.1±6.4nM. In the presence of hsp90, the CaM-nNOS dose-response curve was shifted markedly to the left and the maximal activity was also elevated. Further in vitro protein-binding experiments confirmed that hsp90 increased the binding of CaM to nNOS. Taken together, these data indicate that hsp90 directly augments nNOS catalytic function and that this effect is, at least partially, mediated by CaM-binding enhancement.

scholarly journals A Brain Penetrating Heat-Shock Protein 90 Inhibitor NXD30001 Inhibits Glioblastoma as a Monotherapy or in Combination With Radiation

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Hao Chen ◽  
Jialiang Wang ◽  
Hengli Tian
Keyword(s):  
Stem Cells ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Median Survival ◽  
Therapeutic Potential ◽  
Heat Shock Protein 90 ◽  
Tumor Bearing ◽  
Client Proteins

Abstract INTRODUCTION It has been increasingly recognized that glioblastoma multiforme (GBM) is a highly heterogeneous disease, which is initiated and sustained by molecular alterations in an array of signal transduction pathways. Heat-shock protein 90 (Hsp90) is a molecular chaperone to be critically implicated in folding and activation of a diverse group of client proteins, many of which are key regulators of important glioblastoma biology. METHODS To determine the therapeutic potential of targeting Hsp90 in glioblastoma, we assessed the anti-neoplastic efficacy of NXD30001, a brain-penetrating Hsp90 inhibitor as a monotherapy or in combination with radiation, both in Vitro and in Vivo. RESULTS Our results demonstrated that NXD30001 potently inhibited neurosphere formation, growth and survival of CD133 + glioblastoma stem cells (GSCs) with the half maximal inhibitory concentrations (IC50) at low nanomolar concentrations. At suboptimal concentrations, inhibition of Hsp90 did not exert cytotoxic activity but rather increased radiosensitivity in GSCs. CD133- GBM cells were less sensitive and not radiosensitized by NXD30001. In lines with its cytotoxic and radiosensitizing effects, NXD30001 dose-dependently decreased phosphorylation protein levels of multiple Hsp90 client proteins, including those playing key roles in GSCs, such as EGFR, Akt, c-Myc, and Notch1. In addition, combining NXD30001 with radiation could impair DNA damage response and ER stress response to induce apoptosis of GSCs. Treatment of orthotopic glioblastoma tumors with NXD30001 extended median survival of tumor-bearing mice by approximately 20% (treated 37 days vs vehicle 31 d, P = .0026). Radiation alone increased median survival of tumor-bearing mice from 31 to 38 d, combination with NXD30001 further extended survival to 43 d (P = .0089). CONCLUSION Our results suggest that GBM stem cells (CD133+) are more sensitive to NXD30001 than non-stem GBM cells (CD133-). Furthermore, combination NXD30001 with radiation significantly inhibits GBM progression than use it as a monotherapy by targeting GSCs.

scholarly journals A Pivotal Role for Heat Shock Protein 90 in Ewing Sarcoma Resistance to Anti-Insulin-like Growth Factor 1 Receptor Treatment: In vitro and In vivo Study

2008 ◽  
Vol 68 (15) ◽  
pp. 6260-6270 ◽  
Author(s):  
Ana Sofia Martins ◽  
José Luis Ordoñez ◽  
Alfredo García-Sánchez ◽  
David Herrero ◽  
Victoria Sevillano ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Ewing Sarcoma ◽  
Heat Shock Protein 90 ◽  
Pivotal Role ◽  
In Vivo Study ◽  
Insulin Like Growth Factor

scholarly journals Changes in eNOS phosphorylation contribute to increased arteriolar NO release during juvenile growth

2012 ◽  
Vol 302 (3) ◽  
pp. H560-H566 ◽  
Author(s):  
Lori S. Kang ◽  
Timothy R. Nurkiewicz ◽  
Guoyao Wu ◽  
Matthew A. Boegehold
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Indirect Evidence ◽  
Heat Shock Protein 90 ◽  
Maximal Activity ◽  
Age Related ◽  
Enos Phosphorylation ◽  
No Release ◽  
The Difference

Nitric oxide (NO) mediates a major portion of arteriolar endothelium-dependent dilation in adults, but indirect evidence has suggested that NO contributes minimally to these responses in the young. Isolated segments of arterioles were studied in vitro to verify this age-related increase in NO release and investigate the mechanism by which it occurs. Directly measured NO release induced by ACh or the Ca2+ ionophore A-23187 was five- to sixfold higher in gracilis muscle arterioles from 42- to 46-day-old (juvenile) rats than in those from 25- to 28-day-old (weanling) rats. There were no differences between groups in arteriolar endothelial NO synthase (eNOS) expression or tetrahydrobiopterin levels, and arteriolar l-arginine levels were lower in juvenile vessels than in weanling vessels (104 ± 6 vs.126 ± 3 pmol/mg). In contrast, agonist-induced eNOS Thr495 dephosphorylation and eNOS Ser1177 phosphorylation (events required for maximal activity) were up to 30% and 65% greater, respectively, in juvenile vessels. Juvenile vessels did not show increased expression of enzymes that mediate these events [protein phosphatases 1 and 2A and PKA and PKB (Akt)] or heat shock protein 90, which facilitates Ser1177 phosphorylation. However, agonist-induced colocalization of heat shock protein 90 with eNOS was 34–66% greater in juvenile vessels than in weanling vessels, and abolition of this difference with geldanamycin also abolished the difference in Ser1177 phosphorylation between groups. These findings suggest that growth-related increases in arteriolar NO bioavailability may be due at least partially to changes in the regulation of eNOS phosphorylation and increased signaling activity, with no change in the abundance of eNOS signaling proteins.

Inhibition of the heat shock protein 90 molecular chaperone in vitro and in vivo by novel, synthetic, potent resorcinylic pyrazole/isoxazole amide analogues

2007 ◽  
Vol 6 (4) ◽  
pp. 1198-1211 ◽  
Author(s):  
Swee Y. Sharp ◽  
Chrisostomos Prodromou ◽  
Kathy Boxall ◽  
Marissa V. Powers ◽  
Joanna L. Holmes ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Molecular Chaperone ◽  
Heat Shock Protein 90
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