Role of heat shock protein 90 in hepatitis B virus replication / 临床肝胆病杂志

Hepatitis B virus （HBV） has the characteristics of wide transmission， a high chronic infection rate， and a low cure rate， and improving the cure rate of HBV may help to improve the long－term prognosis of patients. Heat shock protein 90 （Hsp90） is a chaperone protein widely present in organisms. In recent years， more and more studies have shown that Hsp90 is associated with HBV infection and plays an important role in HBV replication. It can not only interact with specific proteins of the virus to promote its replication， but also interact with the host’s own proteins to perform its function. This article reviews the role of Hsp90 in HBV replication in recent studies， so as to provide new theoretical guidance and directions for the development of new anti－HBV drugs targeting Hsp90 and the prevention and treatment of HBV infection in the future.

Influence of serum heat shock protein 90α on the prognosis of patients with hepatocellular carcinoma after transarterial chemoembolization / 临床肝胆病杂志

Objective To investigate the influence of preoperative serum heat shock protein 90α (HSP90α) level on the survival time of patients with hepatocellular carcinoma treated by transarterial chemoembolization (TACE). Methods A retrospective analysis was performed for the clinical data of 97 patients with hepatocellular carcinoma who received TACE alone in Department of Hepatobiliary Surgery, The Affiliated Hospital of Southwest Medical University, from January 1, 2019 to June 1, 2020. With the median of serum HSP90α level as the cut-off value, the patients were divided into high-level group with 48 patients (HSP90α > 135 ng/L) and low-level group with 49 patients (HSP90α ≤135 ng/L). The chi-square test was used for comparison of categorical data between groups. The Kaplan-Meier method was used to calculate the median survival time, and the log-rank test was used for comparison between groups. The log-rank univariate analysis and multivariate Cox regression analysis were used to explore the influencing factors for the survival time of patients after surgery. Results There were significant differences between the high-level group and the low-level group in Child-Pugh class ( χ 2 =19.356, P <0.01), tumor necrosis ( χ 2 =9.964, P =0.002), BCLC staging ( χ 2 =22.356, P <0.01), and ECOG score ( χ 2 =6.644, P <0.05). The high-level group had a significantly shorter median survival time than the low-level group ( χ 2 =15.551, P <0.01). HSP90α level (hazard ratio [ HR ]=1.690, P <0.05) and BCLC staging ( HR =2.373, P <0.05) were independent influencing factors for the survival time of patients with hepatocellular carcinoma after TACE. Conclusion Preoperative serum HSP90α level is an independent influencing factor for the survival time of patients with hepatocellular carcinoma after TACE, and it is expected to become one of the potential indicators for evaluating the prognosis of patients with hepatocellular carcinoma treated by TACE.

Involvement of HSP90 in ischemic postconditioning-induced cardioprotection by inhibition of the complement system, JNK and inflammation

Abstract Purpose To investigate whether heat shock protein 90 (HSP90) is involved in complement regulation in ischemic postconditioning (IPC). Methods The left coronary artery of rats underwent 30 min of occlusion, followed by 120 min of reperfusion and treatment with IPC via 3 cycles of 30s reperfusion and 30s occlusion. The rats were injected intraperitoneally with 1 mg/kg HSP90 inhibitor geldanamycin (GA) after anesthesia. Eighty rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R), IPC and IPC + GA. Myocardial infarct size, apoptosis index and the expression of HSP90, C3, C5a, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1β and c-Jun N-terminal kinase (JNK) were assessed. Results Compared with the I/R injury, the IPC treatment significantly reduced infarct size, release of troponin T, creatine kinase-MB, and lactate dehydrogenase, and cardiomyocyte apoptosis. These beneficial effects were accompanied by a decrease in TNF-α, IL-1β, C3, C5a and JNK expression levels. However, all these effects were abrogated by administration of the HSP90 inhibitor GA. Conclusion HSP90 exerts a profound effect on IPC cardioprotection, and may be linked to the inhibition of the complement system and JNK, ultimately attenuating I/R-induced myocardial injury and apoptosis.

Avaliação de mecanismos de modificação pós-traducional da óxido nítrico sintase endotelial (eNOS) associados a biodisponibilidade do óxido nítrico em artérias de ratas espontaneamente hipertensas (SHR) ao final da prenhez / Evaluation of post-translational modification mechanisms of endothelial nitric oxide synthase (eNOS) associated with the nitric oxide bioavailability in arteries from spontaneously hypertensive rats (SHR) in the end of pregnancy

A redução da reatividade vascular à fenilefrina (PE) em aorta de ratas espontaneamente hipertensas (SHR) ao final da prenhez é dependente de maior produção e/ou maior biodisponibilidade de óxido nítrico (NO), consequente do aumento da fosforilação da enzima óxido nítrico sintase endotelial (eNOS) via PI3K/Akt. A glicosilação do tipo N-acetil-glucosamina (O-GlcNAc) é uma modificação pós-traducional que compete com a fosforilação pelos mesmos sítios de ligação nas proteínas. A O-GlcNAcilação da eNOS em serina1177 leva a redução da sua atividade enquanto a fosforilação leva a sua ativação. Além destes mecanismos, a interação da eNOS com outras proteínas é capaz de regular positiva ou negativamente a sua atividade. O objetivo deste trabalho foi analisar possíveis alterações nos mecanismos de modificação pós-traducional que controlam a ativação da eNOS os quais poderiam contribuir para maior ativação e maior biodisponibilidade de NO observada em artérias de ratas prenhes. Foram avaliados o conteúdo proteico O-GlcNAc e também expressão das enzimas que participam desta modificação, O-GlcNAc transferase (OGT) e O-GlcNAcase (OGA) por Western Blotting e a atividade da OGA por ensaio bioquímico em aorta e em artéria mesentérica (2º ou 3º ramo) de ratas não prenhes (NP) e prenhes (P), normotensas (Wistar) e SHR. Ensaios de Western Blotting foram realizados também para análise da expressão das seguintes proteínas: Cav-1, p-Cav-1, CaM e Hsp90. Realizamos a contagem do número de cavéolas endoteliais da aorta e da artéria mesentérica na presença ou ausência da metil-ß-ciclodextrina (dextrina, 10 mmol/L) por microscopia eletrônica. Em estudos funcionais, avaliamos a participação da enzima OGA, pela inibição com PugNAc (100 µmol/L) e das cavéolas, utilizando um desorganizador de cavéolas, a dextrina (10 ou 20 mmol/L), na menor reatividade vascular à PE observada em aortas de ratas P. Observamos que o conteúdo de proteínas O-GlcNAciladas estava diminuído em aorta e em leito mesentérico de ratas Wistar P e SHR P. Apesar da expressão da OGT e da OGA não estar alterada, a atividade da OGA foi aumentada em aorta e leito mesentérico de ratas Wistar P, mas, encontra-se diminuída em aorta e aumentada em leito mesentérico de SHP P. A incubação com PugNAc reverteu a reduzida reatividade à PE em aorta e artéria mesentérica de ratas Wistar P mas este efeito não foi observado em vasos SHR P, demonstrando que a OGA parece ter um papel importante na redução da O-GlcNAcilação de proteínas vasculares em Wistar P. Em vasos incubados com PugNAc, a remoção do endotélio ou a incubação com L-NAME, não alterou significativamente a reatividade à PE. Juntos estes resultados sugerem que a maior atividade da eNOS observada em vasos de Wistar P, fica prejudicada na presença do PugNAc, e depende da atividade da OGA. Como não houve alteração da resposta contrátil à PE em vasos de SHR P incubados com PugNAc, possivelmente um mecanismo diferente, envolvendo a menor atividade da OGT, ocorre nestas artérias para a redução da O-GlcNAcilação da eNOS. A desorganização das cavéolas por meio da dextrina causou aumento de contração à PE e redução de potência da ACh em aortas de Wistar NP e SHR NP, porém não houve alteração em aortas de ratas Wistar P e SHR P. A dextrina não alterou o número de cavéolas em artérias de Wistar P e SHR P quando comparado com ratas NP. SHR NP apresentam um reduzido número de cavéolas das aortas em relação a Wistar NP bem como expressão reduzida de Cav-1, p-Cav-1 e CaM. A prenhez não foi capaz de alterar a expressão da Cav-1, CaM e Hsp90 em aorta e leito mesentérico de ratas normotensas e hipertensas. Estes resultados sugerem que a prenhez não altera a expressão das proteínas Cav-1, CaM e Hsp90 e possivelmente a interação com a eNOS em aorta e artérias mesentéricas de ratas normotensas e hipertensas. Em conclusão, entre os mecanismos estudados de modificação pós-traducional da eNOS, a redução da O-GlcNAcilação da eNOS, por mecanismos que envolvem a atividade da OGA e possivelmente da OGT, favoreceria a fosforilação da eNOS e consequente maior biodisponibilidade de NO, contribuindo desta forma para modulação da resposta contrátil da PE nas artérias de ratas P(AU)

Reduction of vascular reactivity to phenylephrine (PE) in aorta of spontaneously hypertensive rats (SHR) at the end of pregnancy is dependent on higher production and/or higer bioavailability of nitric oxide (NO), as a consequence of increased endothelial nitric oxide synthase enzyme (eNOS) phosphorylation, by PI3K/Akt. Glycosylation with O-linked N-acetylglucosamine (O-GlcNAc) is a post-translational modification that competes with phosphorylation by the same binding sites in proteins. O-GlcNAcylation of eNOS on serine site leads to a reduction in its activity while eNOS phosphorylation leads to its activation. In addition to these mechanisms, the interaction of eNOS with other proteins is able to regulate positively or negatively its activity. The objective of this study was to analyze possible changes in the mechanisms of post-translational modification that control the eNOS activation, which could contribute to its the greater activation and greater bioavailability of NO observed in arteries of pregnant rats. The O-GlcNAc-protein content and also the enzymes expression that participate in this modification, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) was assessed by Western Blotting, and OGA activity were evaluated by biochemical assay in the aorta and in the artery mesenteric (2nd or 3rd branch) of non-pregnant (NP) and pregnant (P), normotensive rats (Wistar) and SHR. Western Blotting assays were also performed for expression analysis of the following proteins: Cav-1, p-Cav-1, CaM and Hsp90. We performed the counting of the number of endothelial caveolae in the aorta and the mesenteric artery in the presence or absence of methyl-ß-cyclodextrin (dextrin, 10 mmol/L) by electronic microscopy. In functional studies, we evaluated the participation of the OGA enzyme, by inhibition with PugNAc (100 µmol/L) and of the caveolae, using a caveolae disassembler, dextrin (10 or 20 mmol/L), in the reduced vascular reactivity observed in aortas or mesenteric arteries of P rats. We observed that the content of O-GlcNAcylated proteins was decreased in the aorta and in the mesenteric bed of Wistar P and SHR P rats. Although OGT and OGA expression is not altered, OGA activity was increased in the aorta and mesenteric bed of Wistar P rats but was decreased in the aorta and increased in the mesenteric bed of SHP P. Incubation with PugNAc reversed the reduced reactivity to PE in the aorta and mesenteric artery of Wistar P but this effect was not observed in SHR P arteries, demonstrating that OGA appears to play an important role in reducing O-GlcNAcylation of vascular proteins in Wistar P. In arteries incubated with PugNAc, endothelial removal or incubation with L-NAME did not significantly alter reactivity to PE. Together, these results suggest that the greater eNOS activity observed in Wistar P vessels was impaired in the presence of PugNAc, and it depends on OGA activity. As there was no change in the contractile response to PE in SHR P arteries incubated with PugNAc, possibly a different mechanism, involving the lower activity of OGT, occurs in these vessels for the reduction of O-GlcNAcylation of eNOS. Dextrin caused increased contraction of PE and decreased ACh potency in Wistar NP and SHR NP aortas, but there was no change in aortas of Wistar P and SHR P. Dextrin did not alter the number of cavelae in Wistar P and SHR P arteries compared to NP rats. SHR NP showed a lower number of caveolae than to NP Wistar as well reduced expression of Cav-1 and CaM. Pregnancy was not able to alter the expression of Cav-1, CaM and Hsp90 in the aorta and mesenteric bed of normotensive and hypertensive rats. These results suggest that pregnancy does not alter the expression of Cav-1, CaM and Hsp90 proteins and possibly interaction with eNOS in the aorta and mesenteric arteries of normotensive and hypertensive rats. In conclusion, among the studied mechanisms of post-translational modification of eNOS, the reduction of O-GlcNAcylation of eNOS, by mechanisms that involve OGA activity and possibly OGT, would favor eNOS phosphorylation and consequent greater NO bioavailability, contributing in this way for modulation of the contractile response to PE in the arteries of P rats(AU)

Heat shock protein 90 in the diagnosis of gastrointestinal tumors / 中华普通外科杂志

Objective To evaluate HSP90 levels in the diagnosis and staging of gastrointestinal tumors.Method Patients with gastrointestinal tumors hospitalized from 2014 January to 2015 April were enrolled in this study.Serum level of HSP90 was detected.Results The serum HSP90 level of cancer group(112 ± 74)was significantly higher than the control groups,the area under the ROC curve of HSP90's was 0.875 and the cut-off point was 63.63 with sensitivity of 76.1％ and specificity of 92.6％.The HSP90 level in gastric cancer group(135 ±73)ng/ml was the highest,in colon cancer group was (105 ± 60) ng/ml and in rectum cancer group was(79 ± 42)ng/ml (all P ＜ 0.05).Serum HSP90 levels in moderate and low differentiated adenocarcinoma were higher than well differentiated adenocarcinoma group (P ＜ 0.05).Serum HSP90 level was higher in tumors with submucosa and serosa infiltration (P ＜ 0.05).Those with lymphatic metastasis tend to have a higher serum HSP90 level than those without.Conclusion Serum HSP90 level has a good predictive value on gastrointestinal tumor diagnosis,and it is correlated with tumor staging and infiltration status.

HSP90 inhibitor 17-AAG plays an important role in JAK3/STAT5 signaling pathways in HTLV-1 infection cell line HUT-102 / 中华血液学杂志

Objective@#To analyze whether heat-shock protein 90 (HSP90) be involved in a permanently abnormal activated JAK/STAT signaling in ATL cells in vitro.@*Methods@#The effect of 17-AAG on proliferation of ATL cell lines HUT-102 was assessed using CCK8 at different time points. Cell apoptosis was measured by flow cytometry. The specific proteins HSP90, STAT5, p-STAT5 and JAK3 were detected by Western blotting.@*Results@#Overexpression of HSP90 in HUT-102 cell lines was disclosed (P<0.05) , and constitutive activation of JAK3/STAT5 signaling was observed in HTLV-1-infected T-cell lines but not in normal PBMCs; Treatment of ATL cell lines with 17-AAG led to reduced cell proliferation, but there was no significant change in terms of cell proliferation when the concentration of 17-AAG between 2 000-8 000 nmol/L (P>0.05) . 17-AAG induced cell apoptosis in different time-points and concentrations. 17-AAG don’t affect the expression of JAK3 gene.@*Conclusion@#This study indicated that JAK3 as HSP90 client protein was aberrantly activated in HTLV-1-infected T-cell lines, leading to constitutive activation of p-STAT5 in JAK/STAT signal pathway, which demonstrated that HSP90-inhibitors 17-AAG inhibited the growth of HTLV-1-infected T-cell lines by reducing cell proliferation and inducing cell apoptosis.

Apoptosis in response to heat stress is positively associated with heat-shock protein 90 expression in chicken myocardial cells in vitro

To determine heat-shock protein (Hsp)90 expression is connected with cellular apoptotic response to heat stress and its mechanism, chicken (Gallus gallus) primary myocardial cells were treated with the Hsp90 promoter, aspirin, and its inhibitor, geldanamycin (GA), before heat stress. Cellular viability, heat-stressed apoptosis and reactive oxygen species level under different treatments were measured, and the expression of key proteins of the signaling pathway related to Hsp90 and their colocalization with Hsp90 were detected. The results showed that aspirin treatment increased the expression of protein kinase B (Akt), the signal transducer and activator of transcription (STAT)-3 and p-IKKα/β and the colocalization of Akt and STAT-3 with Hsp90 during heat stress, which was accompanied by improved viability and low apoptosis. GA significantly inhibited Akt expression and p-IKKα/β level, but not STAT-3 quantity, while the colocalization of Akt and STAT-3 with Hsp90 was weakened, followed by lower cell viability and higher apoptosis. Aspirin after GA treatment partially improved the stress response and apoptosis rate of tested cells caused by the recovery of Akt expression and colocalization, rather than the level of STAT-3 (including its co-localization with Hsp90) and p-IKKα/β. Therefore, Hsp90 expression has a positive effect on cellular capacity to resist heat-stressed injury and apoptosis. Moreover, inhibition of Hsp90 before stress partially attenuated its positive effects.

Differential Gene Expression of Heat Shock Protein 90 (Hsp90) of Candida albicans obtained from Malaysian and Iranian Patients

Background: Candida albicans (C. albicans) has several virulence factors, in particular heat shock protein 90 (Hsp90), which is expressed by Hsp90 gene. The purposes of this study were to assess the expression of Hsp90 gene in clinical and control isolates of C. albicans obtained from different geographical regions (Malaysia and Iran), different temperatures (25ºC, 37ºC and 42ºC) and mice with candidiasis. Methods: C. albicans isolates were cultured onto sabouraud dextrose agar (SDA). The assessment of the expression of Hsp90 gene was performed using real time-polymerase chain reaction (RT-PCR). Results: The results showed a significant increase in the expression of C. albicans Hsp90 gene under high thermal shock (42ºC) when compared to other temperatures tested (P-value = 0.001). The mean differences in the expression of Hsp90 gene at 37ºC were 0.20 (95% confidence interval (CI) 0.13-0.29) between Malaysian and Iranian controls (P-value = 0.040) and 0.47 (95% CI 0.27-0.60) between Malaysian and Iranian patients (P-value = 0.040). Conclusion: The results demonstrated that the expression of C. albicans Hsp90 gene varied between Malaysian and Iranian subjects, representing the efficacy of geographical and thermal conditions on virulence gene expression.

Study on heat shock protein 90α and β in peripheral blood mononuclear cells in mayasthenia gravis children treated with glucocorticoid / 中国医师杂志

Objective To investigate the expressions of heat shock protein(HSP)90α and HSP90β in peripheral blood mononuclear cells (PBMC) in myasthenia gravis (MG) children before and after glucocorticoid (GC) treatment,and normal control groups.Methods Fresh bloods were collected from 20 cases of children with MG before and after treatment and 19 healthy children.PBMCs were isolated,followed by measurement of the expression levels of HSP90α and β by immunocytochemistry,and HSP90α and β mRNAs by reverse transcription and polymerase chain reaction (RT-PCR).Results The positive cell ratio of HSP90α andβ of MG children before and after of GC treatment was significantly higher than control groups (P ＜ 0.05),and their mRNA expression levels was higher than control groups (P ＜ 0.05).HSP90β in MG children after GC treatment was mainly expressed in the nucleus(P ＜ 0.05).Conclusions HSP90α and β in PBMC of MG children before and after GC treatment were significantly higher than those of normal control groups.HSP90β in MG Children after GC treatment was significantly increased.The present results suggest HSP90β promote GC receptor binding and enhance GC transportation,which promotes and strengthens the physiological and pharmacological effects of GC to improve the clinical symptom of MG children.

Expression of extracellular heat shock protein 90α in human hepatocellular carcinoma cells and its effect on cells migratory and invasive capability / 肿瘤研究与临床

Objective To explore the expression of heat shock protein (HSP) 90α in outside of different metastatic hepatocellular carcinoma (HCC) cell lines and its role in the cells migration and invasion.Methods The expression of HSP90α was detected by Western blot analysis in conditioned media of MHCC97L and MHCC97H with low and high metastatic HCC cell lines.A small molecule cell-impermeant HSP90 inhibitor DMAG-N-oxide was used to inhibit extracellular HSP90α.Changes of the cells migratory and invasive capability were assessed by in vitro motility and invasion assay.The endogenous matrix metalloproteinase 2 (MMP-2) was demonstrated by Zymography.The expression of extracellular co-chaperone HSP70 and MMP-2 were tested by Western blots and the association between HSP90α,HSP70 and MMP-2 was analyzed by immunoprecipitation.The effects of HSP70 knockdown by siRNA,with or without MMP-2 inhibitor Batimastat,on the level of active MMP-2 and cell migration and invasion were also evaluated.Results HSP90α can express both inside and outside of different metastatic HCC cell lines,and the level of expression was consistent with metastasis potentials.After MHCC97-H cells were treated with a special HSP90α inhibitor DMAG-N-oxide for 24 h,the average migratory cell numbers (28.11 ±3.56) had a significantly reduction,compared with those without treatment group (80.12±4.16) and empty control group (82.24±4.12),respectively (P ＜ 0.01).In vitro invasion assay showed the average invaded cell numbers in treatment group (36.54±4.12) were more fewer than without treatment group (95.12±3.48) and empty control group (101.1 1±3.36),respectively (P =0.017),and accompanying with decreasing of the extracellular MMP-2 activity.HSP70 and MMP-2 could express outside of MHCC97-H cells and interact with HSP90α.Small molecular interfere RNA (siRNA) dramatically inhibited HSP70 expression and reduced the interaction HSP90α with MMP-2 and MMP-2 activity outside MHCC97-H cells,and also suppressed MHCC97-H cells migration and invasion.In addition,combining MMP-2 inhibitor had additive inhibition effects.Conclusion Extracellular HSP90α and HSP70 form chaperone complex to assist in MMP-2 activation and increases HCC cells migration and invasion,which maybe a novel therapeutic target against metastatic HCC.

Relationship analysis of the expressions of heat shock protein 70 and heat shock protein 90 genes in bone marrow mononuclear cells with glucocorticoid-resistence in acute lymphoblastic leukemia patients / 中国医师杂志

Objectives To investigate the relationships of the expressions of heat shock protein 70(HSP70) and HSP90 genes in bone marrow mononuclear cells (BMMNCs) with glucocorticoid (GC)-resistence (GCR) in acute lymphoblastic leukemia (ALL) patients.Methods The expressions of HSP70 and HSP90 in bone marrow mononuclear cells from 43 newly diagnosed ALL patients and 16 healthy volunteers were examined by real time polymerase chain reaction.Of them,43 patients received glucocorticoid therapy were divided into GC-sensitive (GCS) group and GC-resistant(GCR) group according to GC response.Results (1)The expressions of HSP70 mRNA (0.95 ± 0.36) and HSP90 mRNA (1.97 ± 0.63) in BMMNCs from ALL patients were significantly higher than that in the controls [(0.28 ±0.17)and (0.62 ±0.21),P＜0.01]; (2)The expressions of HSP70 mRNA(1.09 ± 0.22)and HSP90 mRNA(2.18 ± 0.42) in BMMNCs from GCR group patients were significantly higher than that in the GCS group patients [(0.57 ±0.19)and (1.43 ± 0.35),P ＜ 0.05,P ＜ 0.01] ; (3)The expressions of HSP70 mRNA (0.97 ± 0.34)and HSP90 mRNA (2.01 ± 0.58) in BMMNCs from the ALL patients with high-degree tumor burden were significantly higher than that in the patients with low-degree tumor burden [(0.61 ±0.22) and (1.34 ±0.29),P ＜0.01].Conclusions The mRNA expressions of HSP70 and HSP90 in BMMNCs from GCR group patients were significantly increased.Detection of HSP90 and HSP70 expressions may help ALL patients for prognosis judgment,chemotherapy plan selection and therapeutic effect evaluation.

Cell surface heat shock protein 90 and tumor metastasis / 国际肿瘤学杂志

Heat shock protein 90(Hsp90)is one of the most abundant molecular chaperones whose association is essential to maintain the stability and function of uumerous client proteins,and is the unique target protein for cancer therapy.Over the past years,most attention has been given to the study of the intracelhilar Hsp90.However,a pool of Hsp90 has been described to be present on the cell surface and even to be secreted extracellularly,which plays an important role in modulating cancer cell invasion in vitro and metastasis in vivo.

Effect of anti-apoptotic protein HSP-90 in human multiple myeloma cell line U266 cells with bortezomib / 白血病·淋巴瘤

Objective To investigate the effect of anti-apoptotic protein HSP-90 in human multiple myeloma cell line U266 cells after bertezomib interaction. Methods The HSP-90 mRNA expression in the U266 cells was tested by reverse transcription polymerase chain reaction (RT-PCR) after 4 hours of treatment of bertezomib by different concentration. Results With the of increased concentration of bortezomib, the expression level of HSP-90 αmRNA was also increased in U266 cells. Respectively, quantitative results of HSP-90α are 0.343±0.017, 0.505±0.039, 0.640±0.029, 0.760±0.059, 0.963±0.054 from the low to high concentration of bertezomib groups. And there are statistical difference between each group(P <0.05). However, the HSP-90β quantitative results in 0 nmol/L concentration of bertezomib (0.61±0.022) have statistical difference between 50, 150, 200 nmol/L groups(P <0.05). HSP-90β quantitative results in 50(0.765±0.050)and 100 nmol/L(0.645±0.052) nmol/L groups are different(P <0.05). Compared with 100 nmol/L concentration of bortezomib group, statistical difference also exists in 150 (0.770±0.059) and 200 nmol/L (0.790±0.027)groups (P <0.05). Although there is no obvious increase in the mRNA expression of HSP-90β from the chart, statistical difference existed in the whole data (P <0.05). Conclusion Bortezomib can increase the level expression of HSP-90 mRNA, and especially increase the level expression of HSP-90α mRNA.

Heat shock protein 90 regulates IkappaB kinase complex and NF-kappaB activation in angiotensin II-induced cardiac cell hypertrophy

Heat shock protein 90 (HSP90), one of the most abundant proteins in the cardiac cells is essential for cell survival. Previous studies have shown that angiotensin II induces cardiac cell hypertrophy. However, the role of HSP90 in the angiotensin II-induced cardiac hypertrophy is unclear. In this study, we showed that HSP90 regulated angiotensin II-induced hypertrophy via maintenance of the IkappaB kinase (IKK) complex stability in cardiac cells. An HSP90 inhibitor, geldanamycin (GA), significantly suppressed angiotensin II-induced [3H]leucine incorporation and atrial natriuretic factor expression in cardiac cells. GA also inhibited the NF-kappaB activation induced by angiotensin II. Importantly, treatment with GA caused a degradation of IKKalpha/beta; on the other hand, a proteasome-specific inhibitor restored the level of IKKalpha/beta. We also found that GA prevented HSP90-IKKs complex induced by angiotensin II in cardiac cells. The small interfering RNA (siRNA)-mediated knockdown of HSP90 expression significantly inhibited angiotensin II-induced cell hypertrophy and NF-kappaB activation. These results suggest that angiotensin II-induced cardiac hypertrophy requires HSP90 that regulates the stability and complex of IKK.

Isoflavone-deprived soy peptide suppresses mammary tumorigenesis by inducing apoptosis

During carcinogenesis, NF-kappaB mediates processes associated with deregulation of the normal control of proliferation, angiogenesis, and metastasis. Thus, suppression of NF-kappaB has been linked with chemoprevention of cancer. Accumulating findings reveal that heat shock protein 90 (HSP90) is a molecular chaperone and a component of the IkappaB kinase (IKK) complex that plays a central role in NF-kappaB activation. HSP90 also stabilizes key proteins involved in cell cycle control and apoptosis signaling. We have determined whether the exogenous administration of isoflavone-deprived soy peptide prevents 7,12-dimethylbenz[alpha]anthracene (DMBA)-induced rat mammary tumorigenesis and investigated the mechanism of action. Dietary administration of soy peptide (3.3 g/rat/day) significantly reduced the incidence of ductal carcinomas (50%), the number of tumors per multiple tumor-bearing rats (49%; P < 0.05), and extended the latency period of tumor development (8.07 +/- 0.92 weeks) compared to control diet animals (10.80 +/- 1.30; P < 0.05). Our results have further demonstrated that soy peptide (1) dramatically inhibits the expression of HSP90, thereby suppressing signaling pathway leading to NF-kappaB activation; (2) induces expression of p21, p53, and caspase-3 proteins; and (3) inhibits expression of VEGF. In agreement with our in vivo data, soy peptide treatment inhibited the growth of human breast MCF-7 tumor cells in a dose-dependent manner and induced apoptosis. Taken together, our in vivo and in vitro results suggest chemopreventive and tumor suppressive functions of isoflavone-deprived soy peptide by inducing growth arrest and apoptosis.