- Open Access
Geldanamycin-mediated inhibition of heat shock protein 90 partially activates dendritic cells, but interferes with their full maturation, accompanied by impaired upregulation of RelB
© Trojandt et al.; licensee BioMed Central Ltd. 2014
- Received: 12 December 2013
- Accepted: 10 February 2014
- Published: 13 February 2014
The chaperon heat shock protein 90 (HSP90) constitutes an important target for anti-tumor therapy due to its essential role in the stabilization of oncogenes. However, HSP90 is ubiquitously active to orchestrate protein turnover, chemotherapeutics that target HSP90 may affect immune cells as a significant side effect. Therefore, we asked for potential effects of pharmacological HSP90 inhibition at a therapeutically relevant concentration on human dendritic cells (DCs) as main inducers of both cellular and humoral immune responses, and on human CD4+ T cells as directly activated by DCs and essential to confer B cell help.
Unstimulated human monocyte-derived DCs (MO-DCs) were treated with the prototypical HSP90 inhibitor geldanamycin (GA). Based on dose titration studies performed to assess cytotoxic effects, GA was applied at a rather low concentration, comparable to serum levels of clinically used HSP90 inhibitors. The immuno-phenotype (surface markers, cytokines), migratory capacity, allo T cell stimulatory and polarizing properties (proliferation, cytokine pattern) of GA-treated MO-DCs were assessed. Moreover, effects of GA on resting and differentially stimulated CD4+ T cells in terms of cytotoxicity and proliferation were analysed.
GA induced partial activation of unstimulated MO-DCs. In contrast, when coapplied in the course of MO-DC stimulation, GA prevented the acquisition of a fully mature DC phenotype. Consequently, this MO-DC population exerted lower allo CD4+ T cell stimulation and cytokine production. Furthermore, GA exerted no cytotoxic effect on resting T cells, but abrogated proliferation of T cells stimulated by MO-DCs at either state of activation or by stimulatory antibodies.
HSP90 inhibitors at clinically relevant concentrations may modulate adaptive immune responses both on the level of DC activation and T cell proliferation. Surprisingly, unstimulated DCs may be partially activated by that agent. However, due to the potent detrimental effects of HSP90 inhibitors on stimulated CD4+ T cells, as an outcome a patients T cell responses might be impaired. Therefore, HSP90 inhibitors most probably are not suitable for treatment in combination with immunotherapeutic approaches aimed to induce DC/T cell activation.
- Heat shock protein 90
- Dendritic cell
- T cell
The ubiquitously expressed chaperon heat shock protein 90 (HSP90), often acting together with other chaperons like HSP70, binds to a variety of newly synthesized proteins to support their proper folding and to prevent aggregation and interaction with third party proteins . By now, several hundreds of HSP90 client proteins have been identified, including a number of protooncogenes . Based on the vital role of HSP90 to stabilize mutated oncogenic proteins and to promote accumulation of over-expressed oncogenes , and its high level expression in tumor cells , this chaperone has gained long-standing interest as a molecular target for cancer therapy . In this regard, the prototypic HSP90 inhibitor geldanamycin (GA) exerted strong proapoptotic effects on tumor cells in vitro. Derivatives of GA , and other HSP90 inhibitors , which are optimized in terms of metabolic stability and reduced hepato-toxicity, are being tested in several clinical trials .
In light of the essential role of HSP90 in protein homeostasis in all cell types , it is of vital importance to elucidate consequences of drug-mediated inhibition of HSP90 on the patients’ immune system as required to eradicate drug-resistant tumor cells . In this respect, dendritic cells (DCs) as the main inducers of primary immune responses play an essential role . Stimulation of DCs by pathogen-derived molecular patterns and endogenous danger signals as well as by activated T cells results in the activation and upregulated expression of NF-κB transcription factors like RelB , which in turn orchestrate expression of genes required for functional DC maturation . Inhibition of HSP90 by GA was shown to result in diminished NF-κB activity in tumor cells due to impaired functional activity of NF-κB signaling molecules [15–17]. This suggests a modulatory role of HSP90 for the DC activation state.
Here we show that treatment of MO-DCs with GA at low concentration (0.1 μm) resulted in their partial activation. In contrast, GA interfered with stimulation of MO-DCs. In addition, GA prevented the proliferation of stimulated T cells. These findings suggest that inhibition of HSP90 may differentially affect the DC activation state as well as T cell responses in individuals treated with HSP90-inhibiting chemotherapeutics.
Peripheral blood mononuclear cells (PBMCs) were derived from buffy coats of healthy donors by Ficoll density gradient centrifugation, and monocytes were isolated by plastic adherence for 1 h in 6-well tissue culture plates (Starlab, Hamburg, Germany) as described . Monocytes were differentiated in culture medium (Gibco, Houston, TX), containing 2% (v/v) heat-inactivated (56°C, 30 min) autologous plasma, penicillin (100 U/ml)/streptomycin (100 μg/ml) (both PAA, Pasching, Austria), supplemented with recombinant human (rh) GM-CSF (200 U/ml, Berlex, Seattle, WA), IL-4 (1,000 U/ml; ImmunoTools, Friesoythe, Germany). Cells were fed with fresh medium every other day. On 6 of culture, part of the differentiated MO-DCs was treated with GA (Alexis Biochemicals, Lausen, Switzerland) at the concentrations indicated, and aliquots were stimulated with a cocktail of proinflammatory mediators (each 10 ng/ml of rh IL-1β and rh TNF-α (PeproTech, Hamburg, Germany, and 1 μg/ml prostaglandin E2 (PGE2, Alexis Biochemicals) for two days [18, 19]. Cell lines HEK293T  and IGROV1  were cultured as described.
Cells (MO-DCs: 2×105, HEK293T and IGROV1: 5×104, CD4+ T cells, prepared as outlined below: 5 × 105) were seeded into wells of 96-well cell culture plates (Starlab) in a volume of 100 μl of their respective culture medium, and GA was added at various concentrations as indicated. Aliquots of MO-DCs were supplemented with stimulation cocktail in addition. Two days later, an MTT assay was performed as recommended by the supplier (Promega, Madison, WI).
CD4+ T cells were enriched from PBMCs by positive immunomagnetic separation (MACS, Miltenyi Biotec). CD4+ T cells (105) were cocultured with titrated numbers of allogenic MO-DCs in 96-well plates (Greiner Bio-One, Frickenhausen, Germany) in triplicates in 200 μl of culture medium for 5 days. In some experiments, CD4+ T cells were stimulated with anti-CD3 (1 μg/ml) plus anti-CD28 (0.5 μg/ml) antibodies (both from BioLegend, San Diego, CA) for 5 days, in the absence or presence of GA (0.1 μM). T cell proliferation was assessed by genomic incorporation of [3H] thymidine (0.25 μCi/well) added for the last 16 h of culture, measured in a liquid scintillation counter (1205 Betaplate, LKB Wallac, Turcu, Finnland).
Supernatants of DC cultures were harvested on day 8, and of DC/T cell cocultures on day 5, and contents of IL-5, IL-6, IL-12p40, and INF-γ were measured by ELISA as recommended (all ELISA Kits from eBioscience, San Diego, CA).
Harvested cells (5×105) were incubated for 20 min at 4°C with antibodies: fluorescein isothiocyanate (FITC)-conjugated anti-HLA-DR (L243), phycoerythrin (PE)-cyanine 5-conjugated anti-CD80 (2D10), allophycocyanin-conjugated anti-CD86 (IT2.2) (all from BioLegend), PE-conjugated anti-CD83 (HB15e; BD Pharmingen, San Diego, CA), and corresponding isotype controls, respectively. Afterwards, washed DCs were analysed in a FACSCalibur (BD Biosciences, Franklin Lakes, NJ) equipped with CELLQUEST software (BD). For intracellular detection of Fascin 1 (Fscn1), MO-DCs were permeabilized with methanol (10 min on ice), washed with pre-cooled PBS, and incubated with FITC-conjugated anti-Fscn1 (55 K-2; Dako, Glostrup, Denmark) or isotype control antibody. All samples were analysed at the same fluorescence detector settings in order to allow for direct comparison of mean fluorescence intensities (MFIs).
To prepare 100 μl of DC-loaded collagen matrices, first 5 μl of 7.5% (w/v) Na2CO3 and 10 μl of 10× MEM (Invitrogen) were mixed, and then added to 75 μl of PureCol ® bovine collagen I (Invitrogen). Afterwards, 67 μl of this mixture was further mixed with 33 μl of cell suspension containing 3 × 105 DCs, loaded onto a glass slide covered with a cover slip, and incubated at 37°C for 45 min to allow for gelation. IMDM supplemented with penicillin/streptomycin was then added on top of the collagen gel. Spontaneous migration of MO-DC populations was monitored for about 6 h in 2 min intervals by time-lapse microscopy with a BX61 microscope (UAPO lens 20×/340, NA 0.75), equipped with a FView camera (all Olympus, Hamburg, Germany) using CellP software (SIS, Münster, Germany).
Promoter reporter assays
HEK293T cells were seeded in wells of a 6 well cluster plate (Greiner), and were transfected at a confluence of about 90%. Cells were transfected in parallel with transcription factor (TF) responsive luciferase reporter vectors (pAP1-luc, pCRE-luc, pISRE-luc, pNFAT-luc, pNF-κB-luc, and promoterless negative control; all from Agilent, Palo Alto, CA). For transfection, plasmid DNA (4 μg) was complexed with Fugene HD (2 μl; Promega) for 20 min as recommended by the manufacturer. 5 hr after transfection, cells were harvested and were equally split into wells of a 24 well cluster plate (Greiner). On the following day, triplicates were treated with GA and/or the MO-DC maturation cocktail. One day later, cells were harvested, lysed in passive lysis buffer (Promega), and assayed for luciferase detection in a Turner Designs TD-20/20 luminometer (Promega). Luciferase activities were normalized by the activity of the promoterless reporter.
Western blot analysis
MO-DCs (≥ 1 × 106) were lysed with RIPA buffer (1% (v/v) NP-40, 1% (v/v) sodium deoxycholate, 0.1% (w/v) SDS, 0.15 M NaCl, 0.01 M Na3PO4, 2 mM EDTA, 1 mM dichlorodiphenyltrichloroethane, 0.2 mM Na3VO4, 50 mM NaF, 100 U/ml aprotinin, 1 mM phenylmethylsulfonyl fluoride, and 1% (v/v) of Complete Protease inhibitor cocktail (Roche Diagnostics, Mannheim, Germany). Protein concentrations were quantified by Bradford protein assay (Bio-Rad, Munich, Germany), and 30 μg of protein per sample were assayed. Protein samples were separated on a 10% (w/v) sodium dodecyl sulphate-polyacrylamide gel, and transferred to a nitrocellulose membrane (GE Healthcare Europe, Freiburg, Germany). Western blots were probed with rabbit polyclonal antibodies specific for human p65 NF-κB (C22B4), phospho-p65 NF-κB (Ser536; 93H1), both from Cell Signaling Technology (Boston, MA), RelB (C-19; Santa Cruz Biotechnology, CA), ß-actin (Abcam, Cambridge, UK), and with mouse anti human monoclonal antibody specific for IκB-α (L35A5), followed by incubation with a secondary goat antibody (anti-rabbit or anti-mouse IgG), conjugated with horseradish peroxidase (all from Cell Signaling Technology). ECL plus staining (PerkinElmer, Waltham, MA) served as substrate for horseradish peroxidase.
Data are given as mean ± SEM. Statistically significant differences were analysed by applying the Student’s two-tailed t test.
GA promotes expression of activation markers by unstimulated MO-DCs, but interferes with their stimulation-induced upregulation
MO-DCs at an unstimulated state expressed the proinflammatory cytokines IL-6 and IL-12 at low levels, but at high extent after stimulation (Figure 2b). GA treatment alone exerted no effect on the production of either mediator by MO-DCs under basal conditions. However, when coapplied during stimulation, GA attenuated the otherwise activation-associated increase of either cytokine. Taken together, these findings suggest that GA differentially affects the immuno-phenotype of MO-DCs, depending on their state of activation.
GA impairs the migratory capacity of MO-DCs
The endocytotic capacity, which is characteristic of unstimulated DCs, is downregulated upon activation. Unstimulated MO-DCs pretreated with GA showed lower endocytotic uptake of FITC-labeled dextran than untreated MO-DCs, albeit not significant (Additional file 2: Figure S1). This finding is in line with the notion that GA affects the activation state of unstimulated MO-DCs to a moderate extent.
GA diminishes the T cell activation capacity of stimulated MO-DCs
Cocultures that containd untreated MO-DCs were characterized by low contents of the Th1 marker IFN-γ and of the Th2 cytokine IL-5, and both cytokines were present at strongly enhanced levels in DC/T cell cocultures which contained stimulated MO-DCs (Additional file 3: Figure S2b). Pretreatment of unstimulated and stimulated MO-DCs with GA resulted in reduced production of IFN-γ and IL-5 in DC/T cell cocultures as compared with the corresponding controls (Figure 4b).
Taken together, so far these results show that GA interferes with the stimulation-induced activation of MO-DCs in terms of immuno-phenotype, migration, and T cell stimulatory capacity. In contrast, unstimulated MO-DCs are partially activated in response to treatment with GA.
GA affects distinct signalling pathways, and inhibits stimulation-induced upregulation of RelB in stimulated MO-DCs
Next we analysed the outcome of GA-mediated inhibition of HSP90 on the level of transcription factor (TF) activities as the downstream effectors of cellular signalling. Due to the ubiquitous activity of HSP90, and since MO-DCs are rather refractory towards non-viral transfection and may be partially activated in response to transfection , we used HEK293T cells for these analysis. HEK293T cells were transfected with several TF-responsive luciferase reporter vectors, and rested prior to treatment with GA and/or the MO-DC stimulation cocktail, whose components have been shown to stimulate this cell line (IL-1ß, and TNF-α ; PGE2).
These findings indicate that HSP90 affects the activities of distinct TFs at basal conditions, and in response to stimulation. In light of the well acknowledged importance of NF-κB activity for the DC activation process, and the finding that GA evoked slightly elevated NF-κB activation under basal conditions, we asked for effects of GA on NF-κB regulation in MO-DCs. The ubiquitous NF-κB family member p65 is upregulated in stimulated DCs [13, 28], and its transient activation is reflected by phosphorylation of Ser536 . GA treatment exerted no major effect on the expression level of p65 and the fraction of phosphorylated protein in unstimulated MO-DCs (Figure 5b, left panel). Stimulation of MO-DCs resulted in an increase of p65, as reflected by the arisal of a second band, to a similar extent in both untreated and GA-treated cells. The fraction of Ser536-phosphorylated p65 was unaltered, most probably due to the rather long period of stimulation. We also monitored expression of the ubiquitously expressed endogenous NF-κB inhibitor IκB-α, which is degraded immediately after stimulation of DCs, but strongly upregulated at later time points to limit NF-κB activation . In line, MO-DCs stimulated for 48 h, displayed higher IκB-α levels than unstimulated MO-DCs (Figure 5b, right panel). GA treatment mediated no alterations of IκB-α levels in MO-DCs at either state of activation. While both p65 and IκB-α are expressed in a ubiquitous manner, the NF-κB family member RelB is confined to professional antigen presenting cells (APCs), upregulated in response to stimulation . RelB has proven essential for the acquisition of a mature DC activation state , which prompted us to monitor its expression. As expected, unstimulated MO-DCs expressed RelB at low level, which was increased following stimulation (Figure 5b, right panel). GA treatment of unstimulated MO-DCs yielded a reduced RelB content as compared with untreated MO-DCs. When applied in the course of stimulation, GA prevented the otherwise stimulation-associated increase in RelB expression.
These findings indicate that GA may affect the activities of a number of TFs. These TFs are known to contribute to determine the state of activity of DCs. In this context, NF-κB may play an important role as highlighted by impaired RelB expression in MO-DCs treated with GA in the course of stimulation.
GA does not exert cytotoxic effects on resting T cells, but abrogates their stimulation-induced proliferation
These results indicate that GA may hamper the induction of adaptive immune responses both on the level of DC activation as well as T cell stimulation and/or proliferation.
Here we show that the prototypic HSP90 inhibitor GA exerted cytotoxic effects on human MO-DCs both at unstimulated state as well during stimulation in a dose-dependent manner. We chose a concentration of GA (0.1 μM) devoid of detrimental effects on the viability of MO-DCs to analyze the influence of this agent on the immuno-phenotype and functions of MO-DCs. Of note, this concentration broadly corresponds to plasma levels of GA-derived HSP90 inhibitors used in the course of treatment of patients in clinical trials [32, 33].
Unstimulated MO-DCs treated with GA were characterized by differential regulation of DC surface markers: While CD80 expression levels were reduced, HLA-DR, CD83, and CD86 were upregulated. In accordance with the elevated expression of the latter markers, whose expression is controlled in part by NF-κB , we noted moderately enhanced NF-κB activity in GA-treated HEK293T cells, which may explain in part the enhanced state of activation of likewise treated MO-DCs. However, neither the expression level of the endogenous NF-κB inhibitor IκB-α , nor the level and activation state of the ubiquitously expressed NF-κB family member p65  were altered in GA-treated MO-DCs. Moreover, expression of the largely APC-restricted NF-κB family member RelB  was actually reduced in this MO-DC population. Therefore, further analysis is required to elucidate whether GA treatment results in activation of NF-κB in unstimulated MO-DCs, and which of the other members of this TF family  may be involved. Besides, the partial activation of GA-treated MO-DCs may also result at least in part from reduced activity of signaling pathways and TFs that serve to maintain a low state of activation in DCs. For example, agents that activate the cAMP/PKA signaling axis also induce a largely maturation-resistant DC activation state . In this regard, we observed moderate down-regulation of CREB activity in GA-treated HEK293T cells, and it remains to be analyzed whether impaired CREB activity in turn may favour DC activation.
In striking contrast to our findings of enhanced expression of some DC activation markers in GA-treated MO-DCs, Bae and coworkers  observed profound down-regulation of HLA molecules as well as of all costimulators monitored in MO-DCs subjected to treatment with GA. This discrepancy may be due to GA dose effects, since Bae and coworkers used a tenfold higher dose of GA (1 μM)  than employed by us, which in their study was the only dose tested on MO-DCs to assess apoptosis-inducing effects.
Unstimulated DCs are specialized in the uptake of antigen by various means, including receptor-mediated endocytosis, but cease to engulf antigen upon stimulation . Both in our study and in the report of Bae and coworkers  GA-treated MO-DCs were characterized by slightly decreased endocytotic activity. The finding of a GA-dependent decrease in antigen uptake by MO-DCs supports the notion of a partially activated state. Alternatively, it is possible that proteins involved in receptor-mediated endocytosis may constitute genuine HSP90 client proteins, affected by GA-mediated HSP90 inhibition. Interestingly, HSP90 is required for transfer of internalized antigen from the endosome to the cytosol for subsequent cross-presentation .
In our study, unstimulated GA-treated DCs displayed a slightly enhanced allo CD4+ T cell stimulatory capacity. This finding may be explained in part by the moderately upregulated expression of HLA-DR and of CD83 as well as by the tendency of elevated CD86 surface levels in GA-treated MO-DCs. This may may compensate for the impaired expression of CD80, in order to facilitate elevated antigen presentation and T cell stimulation.
In marked contrast to the partially stimulatory effects of GA on unstimulated MO-DCs, this agent interfered with the stimulation-associated increase in surface expression of all DC activation markers monitored, as well as proinflammatory mediators, while HLA-DR remained largely unaffected. In case of CD80, the only molecule diminished in expression by GA treatment in unstimulated MO-DCs, GA completely abrogated the otherwise stimulation-associated increase in surface expression. This finding suggests that CD80 may be regulated in a qualitatively distinct manner as compared with the other markers assessed. Similarly, Bae and coworkers reported on lower expression of all DC markers monitored for MO-DCs treated with GA (1 μM) during stimulation . However, in that study, effects of GA on DC surface marker expression were not assessed side-by-side in unstimulated and stimulated MO-DCs, given that expression levels of most activation markers shown were lower in stimulated than in unstimulated control MO-DCs. Therefore, it remains unclear whether treatment of MO-DCs with GA at that high dose abolished stimulation-dependent upregulation of surface markers, or only partially inhibited upregulation, as was observed for most molecules in our work for a ten-fold lower dose of GA applied.
In agreement with impaired upregulation of the cytoskeletal protein Fscn1, required for dendrite formation  and migration , MO-DCs cotreated with GA in the course of stimulation were characterized by a lower migratory activity than the corresponding control group. This functional defect may reflect in part impaired actin polymerization, shown to require HSP90 activity .
MO-DCs treated with GA during stimulation, in accordance with reduced upregulation of DC activation markers and proinflammatory cytokines, exhibited lower allo CD4+ T cell activation capacity as compared with stimulated control MO-DCs. Consequently, the corresponding DC/T cell cocultures contained lower levels of the Th1/Th2 effector cytokines  IFN-γ, and IL-5.
In general, stimulation of MO-DCs results in the activation of a number of signaling pathways, and a number of key regulators have been reported to constitute client proteins of HSP90. In this regard, STAT1 has been identified as a genuine HSP90 target . Here we show that GA-treated HEK293T cells displayed impaired STAT1/2 activity under basal conditions, and impaired upregulation in response to stimulation. In stimulated DCs, STAT1 has been demonstrated to mediate increased expression of activation markers like CD40 , and its inhibition may contribute to impaired DC maturation.
Moreover, MAPK members JNK , and p38  have been shown to positively regulate DC activation, and both kinases interact with HSP90 (JNK , p38 ). Both MAPK are known to activate PKC, which in turn mediates phosphorylation-dependent activation of TFs of the AP-1 family that are important i.e. for expression of MMP-9 in stimulated DCs as a prerequisite for emigration from the periphery . In line with the relevance of HSP90-mediated protein maturation of either MAPK, we observed impaired upregulation of AP-1 activity in HEK293T cells cotreated with GA and the maturation cocktail. Besides, stimulation-dependent MAPK activation is known increase of NF-κB activity , based on transient degradation of the endogenous inhibitor IκB-α , and in case of APCs also on elevated expression and activity of the NF-κB family member RelB . In case of DCs, RelB is essential for stimulation-dependent increases of activation marker expression and consequently the T cell stimulatory capacity . Therefore, our finding of GA-dependently impaired RelB expression in stimulated Mo-DCs may explain in part the detrimental effects of this agent on the phenotype and function of stimulated Mo-DCs. In HEK293T cells, GA-treatment mediated no detrimental effect on the stimulation-associated increase in NF-κB activity, which may be explained by the APC-specific character of RelB expression . However, in previous studies inhibition of HSP90 by GA was shown to diminish NF-κB activity in tumor cells due to impaired expression of the NK-κB signaling regulators IKK , NIK , and RIP1 . Limited activity of either regulator may contribute to attenuated RelB expression in stimulated MO-DCs cotreated with GA.
In T cells GA may inhibit the expression of the tyrosine kinase lck, and impair its stimulation-induced phosphorylation as evidenced in a human T cell line (Jurkat) [52, 53]. Due to this early block in T cell activation, IL-2 production of stimulated T cells was largely abrogated. Most recently, GA was demonstrated to affect as well the expression of several T cell receptor-associated molecules, namely TCRαß, CD4 and CD28 . In accordance, GA prevented the proliferation of lymphocytes treated with stimulatory antibodies  and of T cells stimulated by either MO-DCs or mitogen . In line, we observed largely abrogated proliferation of CD4+ T cells stimulated by unstimulated or stimulated MO-DCs or by application of stimulatory antibodies.
Our study has shown that GA-mediated inhibition of HSP90 in unstimulated MO-DCs may result in partial activation of the cells by yet unknown mechanisms. On the other hand, GA treatment impaired MO-DC stimulation and largely abrogated both polyclonal and DC-mediated T cell proliferation. Chemotherapeutics that act to inhibit HSP90 may therefore exert rather inhibitory effects on the patients’ immune system, and most likely are not preferable for combination with immunotherapy that targets the DC/T cell axis to mount potent anti-tumor responses.
We thank Claudia Eider and Dr. Dirk Prawitt (both Center for Pediatrics and Adolescent Medicine, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany) for providing us with the cell line IGROV1. This study was supported by grants of the University Medical Center Mainz (MAIFOR program), and of the Deutsche Forschungsgemeinschaft (grant number RE 617/1-1).
Stefanie Trojandt did partial fulfillment of the requirements of the doctoral thesis.
- da Silva VC, Ramos CH: The network interaction of the human cytosolic 90 kDa heat shock protein Hsp90: a target for cancer therapeutics. J Proteomics. 2012, 75: 2790-2802. 10.1016/j.jprot.2011.12.028.View ArticlePubMedGoogle Scholar
- Echeverría PC, Bernthaler A, Dupuis P, Mayer B, Picard D: An interaction network predicted from public data as a discovery tool: application to the Hsp90 molecular chaperone machine. PLoS One. 2011, 6: e26044-10.1371/journal.pone.0026044.PubMed CentralView ArticlePubMedGoogle Scholar
- Whitesell L, Lindquist SL: HSP90 and the chaperoning of cancer. Nat Rev Cancer. 2005, 5: 761-772. 10.1038/nrc1716.View ArticlePubMedGoogle Scholar
- Cheng Q, Chang JT, Geradts J, Neckers LM, Haystead T, Spector NL, Lyerly HK: Amplification and high-level expression of heat shock protein 90 marks aggressive phenotypes of human epidermal growth factor receptor 2 negative breast cancer. Breast Cancer Res. 2012, 14: R62-10.1186/bcr3168.PubMed CentralView ArticlePubMedGoogle Scholar
- Whitesell L, Lin NU: HSP90 as a platform for the assembly of more effective cancer chemotherapy. Biochim Biophys Acta. 1823, 2012: 756-766.Google Scholar
- Whitesell L, Mimnaugh EG, De Costa B, Myers CE, Neckers LM: Inhibition of heat shock protein HSP90-pp60v-src heteroprotein complex formation by benzoquinone ansamycins: essential role for stress proteins in oncogenic transformation. Proc Natl Acad Sci USA. 1994, 91: 8324-8328. 10.1073/pnas.91.18.8324.PubMed CentralView ArticlePubMedGoogle Scholar
- Taldone T, Gozman A, Maharaj R, Chiosis G: Targeting Hsp90: small-molecule inhibitors and their clinical development. Curr Opin Pharmacol. 2008, 8: 370-374. 10.1016/j.coph.2008.06.015.PubMed CentralView ArticlePubMedGoogle Scholar
- Jhaveri K, Taldone T, Modi S, Chiosis G: Advances in the clinical development of heat shock protein 90 (Hsp90) inhibitors in cancers. Biochim Biophys Acta. 1823, 2012: 742-755.Google Scholar
- Travers J, Sharp S, Workman P: HSP90 inhibition: two-pronged exploitation of cancer dependencies. Drug Discov Today. 2012, 17: 242-252. 10.1016/j.drudis.2011.12.021.View ArticlePubMedGoogle Scholar
- Taipale M, Jarosz DF, Lindquist S: HSP90 at the hub of protein homeostasis: emerging mechanistic insights. Nat Rev Mol Cell Biol. 2010, 11: 515-528. 10.1038/nrm2918.View ArticlePubMedGoogle Scholar
- Mellman I, Coukos G, Dranoff G: Cancer immunotherapy comes of age. Nature. 2011, 480: 480-489. 10.1038/nature10673.PubMed CentralView ArticlePubMedGoogle Scholar
- Steinman RM, Banchereau J: Taking dendritic cells into medicine. Nature. 2007, 449: 419-426. 10.1038/nature06175.View ArticlePubMedGoogle Scholar
- Hofer S, Rescigno M, Granucci F, Citterio S, Francolini M, Ricciardi-Castagnoli P: Differential activation of NF-kappa B subunits in dendritic cells in response to Gram-negative bacteria and to lipopolysaccharide. Microbes Infect. 2001, 3: 259-265. 10.1016/S1286-4579(01)01378-8.View ArticlePubMedGoogle Scholar
- Kaisho T, Tanaka T: Turning NF-kappaB and IRFs on and off in DC. Trends Immunol. 2008, 29: 329-336. 10.1016/j.it.2008.03.005.View ArticlePubMedGoogle Scholar
- Qing G, Yan P, Xiao G: Hsp90 inhibition results in autophagy-mediated proteasome-independent degradation of IkappaB kinase (IKK). Cell Res. 2006, 16: 895-901. 10.1038/sj.cr.7310109.View ArticlePubMedGoogle Scholar
- Qing G, Yan P, Qu Z, Liu H, Xiao G: Hsp90 regulates processing of NF-kappa B2 p100 involving protection of NF-kappa B-inducing kinase (NIK) from autophagy-mediated degradation. Cell Res. 2007, 17: 520-530. 10.1038/cr.2007.47.View ArticlePubMedGoogle Scholar
- Bai L, Xu S, Chen W, Li Z, Wang X, Tang H, Lin Y: Blocking NF-κB and Akt by Hsp90 inhibition sensitizes Smac mimetic compound 3-induced extrinsic apoptosis pathway and results in synergistic cancer cell death. Apoptosis. 2011, 16: 45-54. 10.1007/s10495-010-0542-4.PubMed CentralView ArticlePubMedGoogle Scholar
- Jonuleit H, Kühn U, Müller G, Steinbrink K, Paragnik L, Schmitt E, Knop J, Enk AH: Pro-inflammatory cytokines and prostaglandins induce maturation of potent immunostimulatory dendritic cells under fetal calf serum-free conditions. Eur J Immunol. 1997, 27: 3135-3142. 10.1002/eji.1830271209.View ArticlePubMedGoogle Scholar
- Bellinghausen I, Brand U, Knop J, Saloga J: Comparison of allergen-stimulated dendritic cells from atopic and nonatopic donors dissecting their effect on autologous naive and memory T helper cells of such donors. J Allergy Clin Immunol. 2000, 105: 988-996. 10.1067/mai.2000.105526.View ArticlePubMedGoogle Scholar
- Graham FL, Smiley J, Russell WC, Nairn R: Characteristics of a human cell line transformed by DNA from human adenovirus type 5. J Gen Virol. 1977, 36: 59-74. 10.1099/0022-1317-36-1-59.View ArticlePubMedGoogle Scholar
- Bénard J, da Silva J, de Blois MC, Boyer P, Duvillard P, Chiric E, Riou G: Characterization of a human ovarian adenocarcinoma line, IGROV1, in tissue culture and in nude mice. Cancer Res. 1985, 45: 4970-4979.PubMedGoogle Scholar
- Ross R, Ross XL, Schwing J, Längin T, Reske-Kunz AB: The actin-bundling protein fascin is involved in the formation of dendritic processes in maturing epidermal Langerhans cells. J Immunol. 1998, 160: 3776-3782.PubMedGoogle Scholar
- Al-Alwan MM, Rowden G, Lee TD, West KA: Fascin is involved in the antigen presentation activity of mature dendritic cells. J Immunol. 2001, 166: 338-345.View ArticlePubMedGoogle Scholar
- Gunzer M, Schäfer A, Borgmann S, Grabbe S, Zänker KS, Bröcker EB, Kämpgen E, Friedl P: Antigen presentation in extracellular matrix: interactions of T cells with dendritic cells are dynamic, short lived, and sequential. Immunity. 2000, 13: 323-332. 10.1016/S1074-7613(00)00032-7.View ArticlePubMedGoogle Scholar
- Breckpot K, Heirman C, Neyns B, Thielemans K: Exploiting dendritic cells for cancer immunotherapy: genetic modification of dendritic cells. J Gene Med. 2004, 6: 1175-1188. 10.1002/jgm.615.View ArticlePubMedGoogle Scholar
- Fiorentino L, Stehlik C, Oliveira V, Ariza ME, Godzik A, Reed JC: A novel PAAD-containing protein that modulates NF-kappa B induction by cytokines tumor necrosis factor-alpha and interleukin-1beta. J Biol Chem. 2002, 277: 35333-35340. 10.1074/jbc.M200446200.View ArticlePubMedGoogle Scholar
- Li R, Mouillesseaux KP, Montoya D, Cruz D, Gharavi N, Dun M, Koroniak L, Berliner JA: Identification of prostaglandin E2 receptor subtype 2 as a receptor activated by OxPAPC. Circ Res. 2006, 98: 642-650. 10.1161/01.RES.0000207394.39249.fc.View ArticlePubMedGoogle Scholar
- Neumann M, Fries HW, Scheicher C, Keikavoussi P, Kolb-Mäurer A, Bröcker EB, Serfling E, Kämpgen E: Differential expression of Rel/NF-κB and octamer factors is a hallmark of the generation and maturation of dendritic cells. Blood. 2000, 95: 277-285.PubMedGoogle Scholar
- Doyle SL, Jefferies CA, O’Neill LA: Bruton’s tyrosine kinase is involved in p65-mediated transactivation and phosphorylation of p65 on serine 536 during NFkappaB activation by lipopolysaccharide. J Biol Chem. 2005, 280: 23496-23501. 10.1074/jbc.C500053200.View ArticlePubMedGoogle Scholar
- Scott ML, Fujita T, Liou HC, Nolan GP, Baltimore D: The p65 subunit of NF-kappa B regulates I kappa B by two distinct mechanisms. Gen Dev. 1993, 7: 1266-1276. 10.1101/gad.7.7a.1266.View ArticleGoogle Scholar
- Li M, Zhang X, Zheng X, Lian D, Zhang ZX, Ge W, Yang J, Vladau C, Suzuki M, Chen D, Zhong R, Garcia B, Jevnikar AM, Min WP: Immune modulation and tolerance induction by RelB-silenced dendritic cells through RNA interference. J Immunol. 2007, 178: 480-487.View ArticleGoogle Scholar
- Gartner EM, Silverman P, Simon M, Flaherty L, Abrams J, Ivy P, Lorusso PM: A phase II study of 17-allylamino-17-demethoxygeldanamycin in metastatic or locally advanced, unresectable breast cancer. Breast Cancer Res Treat. 2012, 131: 933-937. 10.1007/s10549-011-1866-7.View ArticlePubMedGoogle Scholar
- Pacey S, Gore M, Chao D, Banerji U, Larkin J, Sarker S, Owen K, Asad Y, Raynaud F, Walton M, Judson I, Workman P, Eisen T: A Phase II trial of 17-allylamino, 17-demethoxygeldanamycin (17-AAG, tanespimycin) in patients with metastatic melanoma. Invest New Drugs. 2012, 30: 341-349. 10.1007/s10637-010-9493-4.View ArticlePubMedGoogle Scholar
- Baeuerle PA, Baltimore D: I kappa B: a specific inhibitor of the NF-kappa B transcription factor. Science. 1988, 242: 540-546. 10.1126/science.3140380.View ArticlePubMedGoogle Scholar
- Hayden MS, West AP, Ghosh S: NF-kappaB and the immune response. Oncogene. 2006, 25: 6758-6780. 10.1038/sj.onc.1209943.View ArticlePubMedGoogle Scholar
- Burkly L, Hession C, Ogata L, Reilly C, Marconi LA, Olson D, Tizard R, Cate R, Lo D: Expression of relB is required for the development of thymic medulla and dendritic cells. Nature. 1995, 373: 531-536. 10.1038/373531a0.View ArticlePubMedGoogle Scholar
- Fujita S, Seino K, Sato K, Sato Y, Eizumi K, Yamashita N, Taniguchi M, Sato K: Regulatory dendritic cells act as regulators of acute lethal systemic inflammatory response. Blood. 2006, 107: 3656-3664. 10.1182/blood-2005-10-4190.View ArticlePubMedGoogle Scholar
- Bae J, Mitsiades C, Tai YT, Bertheau R, Shammas M, Batchu RB, Li C, Catley L, Prabhala R, Anderson KC, Munshi NC: Phenotypic and functional effects of heat shock protein 90 inhibition on dendritic cell. J Immunol. 2007, 178: 7730-7737.View ArticlePubMedGoogle Scholar
- Hopkins RA, Connolly JE: The specialized roles of immature and mature dendritic cells in antigen cross-presentation. Immunol Res. 2012, 53: 91-107. 10.1007/s12026-012-8300-z.View ArticlePubMedGoogle Scholar
- Imai T, Kato Y, Kajiwara C, Mizukami S, Ishige I, Ichiyanagi T, Hikida M, Wang JY, Udono H: Heat shock protein 90 (HSP90) contributes to cytosolic translocation of extracellular antigen for cross-presentation by dendritic cells. Proc Natl Acad Sci USA. 2011, 108: 16363-16368. 10.1073/pnas.1108372108.PubMed CentralView ArticlePubMedGoogle Scholar
- Ross R, Jonuleit H, Bros M, Ross XL, Yamashiro S, Matsumura F, Enk AH, Knop J, Reske-Kunz AB: Expression of the actin-bundling protein fascin in cultured human dendritic cells correlates with dendritic morphology and cell differentiation. J Invest Dermatol. 2000, 115: 658-663. 10.1046/j.1523-1747.2000.00112.x.View ArticlePubMedGoogle Scholar
- Taiyab A, Rao CHM: HSP90 modulates actin dynamics: inhibition of HSP90 leads to decreased cell motility and impairs invasion. Biochim Biophys Acta. 1813, 2011: 213-221.Google Scholar
- Shurin MR, Lu L, Kalinski P, Stewart-Akers AM, Lotze MT: Th1/Th2 balance in cancer, transplantation and pregnancy. Springer Semin Immunopathol. 1999, 21: 339-359. 10.1007/BF00812261.View ArticlePubMedGoogle Scholar
- Howard M, Roux J, Lee H, Miyazawa B, Lee JW, Gartland B, Howard AJ, Matthay MA, Carles M, Pittet JF: Activation of the stress protein response inhibits the STAT1 signalling pathway and iNOS function in alveolar macrophages: role of Hsp90 and Hsp70. Thorax. 2010, 65: 346-353. 10.1136/thx.2008.101139.PubMed CentralView ArticlePubMedGoogle Scholar
- Jackson SH, Yu CR, Mahdi RM, Ebong S, Egwuagu CE: Dendritic cell maturation requires STAT1 and is under feedback regulation by suppressors of cytokine signaling. J Immunol. 2004, 172: 2307-2315.View ArticlePubMedGoogle Scholar
- Nakahara T, Uchi H, Urabe K, Chen Q, Furue M, Moroi Y: Role of c-Jun N-terminal kinase on lipopolysaccharide induced maturation of human monocyte-derived dendritic cells. Int Immunol. 2004, 16: 1701-1709. 10.1093/intimm/dxh171.View ArticlePubMedGoogle Scholar
- Arrighi JF, Rebsamen M, Rousset F, Kindler V, Hauser C: A critical role for p38 mitogen-activated protein kinase in the maturation of human blood-derived dendritic cells induced by lipopolysaccharide, TNF-alpha, and contact sensitizers. J Immunol. 2001, 166: 3837-3845.View ArticlePubMedGoogle Scholar
- Nieto-Miguel T, Gajate C, González-Camacho F, Mollinedo F: Proapoptotic role of Hsp90 by its interaction with c-Jun N-terminal kinase in lipid rafts in edelfosine-mediated antileukemic therapy. Oncogene. 2008, 27: 1779-1787. 10.1038/sj.onc.1210816.View ArticlePubMedGoogle Scholar
- Ota A, Zhang J, Ping P, Han J, Wang Y: Specific regulation of noncanonical p38alpha activation by Hsp90-Cdc37 chaperone complex in cardiomyocyte. Circ Res. 2010, 106: 1404-1412. 10.1161/CIRCRESAHA.109.213769.PubMed CentralView ArticlePubMedGoogle Scholar
- Yen JH, Kocieda VP, Jing H, Ganea D: Prostaglandin E2 induces matrix metalloproteinase 9 expression in dendritic cells through two independent signaling pathways leading to activator protein 1 (AP-1) activation. J Biol Chem. 2011, 286: 38913-38923. 10.1074/jbc.M111.252932.PubMed CentralView ArticlePubMedGoogle Scholar
- Shih VF, Davis-Turak J, Macal M, Huang JQ, Ponomarenko J, Kearns JD, Yu T, Fagerlund R, Asagiri M, Zuniga EI, Hoffmann A: Control of RelB during dendritic cell activation integrates canonical and noncanonical NF-κB pathways. Nat Immunol. 2012, 13: 1162-1170. 10.1038/ni.2446.PubMed CentralView ArticlePubMedGoogle Scholar
- Yorgin PD, Hartson SD, Fellah AM, Scroggins BT, Huang W, Katsanis E, Couchman JM, Matts RL, Whitesell L: Effects of geldanamycin, a heat-shock protein 90-binding agent, on T cell function and T cell nonreceptor protein tyrosine kinases. J Immunol. 2000, 164: 2915-2923.View ArticlePubMedGoogle Scholar
- Schnaider T, Somogyi J, Csermely P, Szamel M: The Hsp90-specific inhibitor geldanamycin selectively disrupts kinase-mediated signaling events of T-lymphocyte activation. Cell Stress Chaperones. 2000, 5: 52-61. 10.1379/1466-1268(2000)005<0052:THSIGS>2.0.CO;2.PubMed CentralView ArticlePubMedGoogle Scholar
- Bae J, Munshi A, Li C, Samur M, Prabhala R, Mitsiades C, Anderson KC, Munshi NC: Heat shock protein 90 is critical for regulation of phenotype and functional activity of human T lymphocytes and NK cells. J Immunol. 2013, 190: 1360-1371. 10.4049/jimmunol.1200593.View ArticlePubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.