Heat Shock Protein 90 Inhibitor Research Articles

354 Heat Shock Protein 90 Inhibitor Attenuates Inflammation Induced by 12-O-tetradecanoylphorbol-13-acetate in Primary Human Keratinocytes and Mice

Heat shock protein 90 (HSP90) is a molecular chaperone that folds and promotes the activity of a wide range of client proteins, including key signaling proinflammatory molecules involved in aberrant inflammation. RGRN-305 is a novel HSP90 inhibitor that has been reported to exhibit antiinflammatory properties in autoimmune skin diseases. Here, the antiinflammatory effects of RGRN-305 were investigated in vitro and in a mouse model in vivo. In primary human keratinocytes stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA; inducer of inflammation), the mRNA expression of the proinflammatory cytokines TNFα, IL-1β, IL-6 and IL-8 were significantly reduced by preincubation with RGRN-305, when measured by quantitative real-time PCR.

Calycosin ameliorates spinal cord injury by targeting Hsp90 to inhibit oxidative stress and apoptosis of nerve cells

BackgroundZhenbao pill is effective in protecting against spinal cord injury (SCI). We attempt to explore the characteristics of calycosin (a main monomer of Zhenbao pill) in SCI and its relative mechanism. MethodsThe target of calycosin was screened using pharmacological network analysis. The SCI cell model was constructed using hydrogen peroxide (H2O2), and the animal model was developed by compressing spinal cord with a vascular clamp. Flow cytometry was conducted to test reactive oxygen species (ROS) levels and cell apoptosis. Detection of malondialdehyde (MDA) activity and Superoxide dismutase (SOD) activity were performed using relative kits. Heat shock protein 90 (HSP90) was examined using western blot and quantitative real-time PCR. Motor function tests were carried out. The hematoxylin-eosin and Nissl staining were conducted. ResultsIn SCI models, ROS, MDA, and cell apoptosis were elevated, SOD and HSP90 levels were restrained, while calycosin addition reversed the above results. Besides, calycosin application or HSP90 overexpression enhanced phosphorylation of protein kinase B (Akt) but weakened that of apoptosis signal-regulating kinase 1 (ASK1) and p38, while HSP90 inhibitor 17-AAG treatment restrained the above results. Meanwhile, the injection of calycosin improved the motor function in SCI model rats. Furthermore, the pathologic results also clarified the positive effect of calycosin on SCI. ConclusionHSP90 was lowly expressed in SCI models. Calycosin alleviated SCI by promoting HSP90 up-regulation and inhibiting oxidative stress and apoptosis of nerve cells.

HSP90β chaperoning SMURF1-mediated LATS proteasomal degradation in the regulation of bone formation

Heat shock protein 90 (HSP90) molecular chaperone is responsible for the stabilization and biological activity of a diverse set of client proteins. We have previously demonstrated that inhibition of HSP90 by 17-Demethoxy-17-allyaminogeldanmycin (17-AAG) not only reverses the glucocorticoid-induced bone loss but also enhances the basal level of bone mass in mice. Here, we investigate the potential mechanism underlying HSP90-associated osteoblast differentiation and bone formation. Knockdown of HSP90β but not HSP90α or inhibition of HSP90 by 17-AAG or NVP-BEP800 negates the protein levels of large tumor suppressor (LATS), the core kinases of Hippo signaling, resulting in the inactivation of LATS and activation of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), in the enhancement of osteoblastic differentiation. In contrast, genetic ablation of Lats1 in mesenchymal stem cells is sufficient to abolish the HSP90 inhibition-induced osteoblastic differentiation and bone formation. Mechanistically, HSP90β but not HSP90α chaperones and prevents the SMAD specific E3 ubiquitin protein ligase 1 (SMURF1)-mediated and ubiquitination-dependent LATS protein proteasomal degradation, whereas 17-AAG abolishes these effects of HSP90β. Thus, these results uncover the HSP90β chaperoning SMURF1-mediated LATS protein proteasomal degradation and the subsequent YAP/TAZ activation as a hitherto uncharacterized mechanism controlling osteoblastic differentiation and bone formation.

Mechanism of HSP90 Inhibitor in the Treatment of DSS-induced Colitis in Mice by Inhibiting MAPK Pathway and Synergistic Effect of Compound Sophorae Decoction.

The mechanism of Heat Shock Protein 90 (HSP90) in Ulcerative Colitis (UC) has been studied, and mitogenic-activated protein kinases (MAPK) also contribute to the pathogenesis of UC. However, the effect of the HSP90/MAPK pathway in UC is still unclear. Therefore, the mainstay of this research is to explore the mechanism of action of this pathway in UC. Compound sophorae decoction (CSD), as a Chinese herbal decoction, can synergistically affect the above process. This study aimed to uncover the synergistic effects of HSP90 inhibitors regulating the MAPK pathway for treating DSS-induced colitis in mice and the synergistic effects of CSD. This experiment used oral administration of standard diets containing 3% dextran sodium sulfate (DSS) to establish an experimental colitis model in mice. The model was treated with HSP90 inhibitor, CSD, or dexamethasone. Mouse feces, mobility, body weight, colon length, and colon histopathology scores were recorded daily to assess the degree of colitis inflammation. Expression levels of HSP90 and MAPK pathway-related genes and proteins were evaluated by Western blot and qPCR. The evaluation of intestinal mucosal permeability was measured by enzyme-linked immunosorbent assay (ELISA), which could detect the protein level of D-Amino Acid Oxidase (DAO) and D-lactic acid (D-LA). The same went for downstream molecules AFT-2, p53, and apoptosis-related proteins BAX, BCL-2, Caspase3, and survivin in the MAPK pathway. Immunohistochemical measured p-38, p-JNK, and p-ERK expressions. JAM-A and claudin-1 connexin were tested by immunofluorescence staining. The TUNEL method was for measuring the apoptosis rate of colonic epithelial cells. CBA kit determined the level of inflammatory factors of colons. HSP90 inhibitor can improve the degree of pathological damage in the colon of mice treated with DSS, increase the mice's weight and the length of the colon, and significantly reduce the disease activity index (DAI) score. Intraperitoneal injection of HSP90 inhibitor can reduce the expression of MAPK pathway markers P38, JNK, ERK, and their phosphorylation and decrease the content of AFT-2 and p53, which is downstream of the MAPK pathway. In addition, treatment of the HSP90 inhibitor up-regulated the expression of anti-apoptotic proteins BCL-2 and survivin, as well as down-regulated apoptotic protein caspase3, BAX in the colon of mice with colitis. Lower levels of inflammatory factors such as IL-6, MCP-1, IFN-γ, TNF, IL-12p70, and increased IL-10 were observed after HSP90 inhibitor therapy. Furthermore, the combination treatment of CSD can enhance the effect of the single HSP90 inhibitor treatment and play a synergistic effect. These data suggest that an HSP90 inhibitor is available to treat UC by inhibiting the MAPK signaling pathway. This axis can restore the intestinal mucosa barrier's function by reducing intestinal mucosa's permeability and inhibiting apoptosis of intestinal epithelial cells. The specific mechanism is that HSP90 inhibitor can reduce the pathological damage and inflammation levels of colitis mice, and reduce the apoptosis rate of colonic epithelial cells and the mucosal permeability, thereby restoring the mucosal barrier function. During this process, CSD works synergistically to improve the therapeutic effect of the HSP90 inhibitor.

RF07 | PSUN356 Synergistic Combination of HSP90 and PI3K inhibitors in Adrenocortical Cancer

Abstract Adrenocortical cancer (ACC) is a rare and aggressive cancer (0.5-2 cases/ million/ year) with a poor 5-year survival (<40%). Most patients inevitably succumb to the wide-spread metastasis because of the lack of effective systemic treatment options or to complications from uncontrolled hypercortisolism. Therefore, it is critically important to identify new effective treatments that can be readily used in a clinical trial. In this direction, we identified a potent synergistic combination of Heat Shock Protein 90 (HSP90) and PI3K inhibitors via quantitative high-throughput drug screening (qHTS) for ACC, using a pharmaceutical library comprised of ∼5000 drugs (FDA approved or investigational), and evaluation of drug synergy by a computerized drug combination matrix analysis. The synergistic efficacy of HSP90 inhibitor STA9090 and PI3K inhibitor, PIK75 was validated in vitro, in ACC cell lines H295R and SW13, by proliferation assay, which also determined the most efficacious doses of individual and combinatorial drugs. The drug combination significantly induced apoptosis and disintegrated the 3D-ACC spheroids as compared to the individual drugs, with a simultaneous upregulation of apoptotic protein markers (cleaved-Caspase3, cleaved-PARP), inhibition of the phosphorylation of PI3K pathway members (AKT1, mTOR, S6K, 4EB1 and GSK3α/β), and alteration in the G2/M phase of the cell cycle, in ACC cells. The synergetic effect of the drug combination was also effective in reducing the metastatic potential as revealed by invasion/migration assay, which was confirmed by the downregulation of the mesenchymal protein (Vimentin, N-cadherin, SNAIL and Zeb1) markers. Consistent with our data, observations from the gene expression data from The Cancer Genome Analysis (TCGA) & Gene Expression Omnibus (GEO) databases, revealed significant mRNA overexpression of HSP90AA1, HSP90AB1 HSP90B1 and its clients AKT2, CDK1, CDK4, NR3C1 indicating both HSP90 and PI3K/AKT pathways are highly activated in ACC cohorts. Overexpression and a positive correlation of mesenchymal markers TWIST1, ZEB1, VIM with HSP90AB1 and PI3KCA, in GEO and TCGA respectively, was consistent with the invasive potential of the ACC cells. In conclusion, our studies on the combination of HSP90 and PI3K inhibitors demonstrated a promising preliminary synergistic efficacy by inhibiting proliferation and epithelial-to-mesenchymal transition of ACC. Our findings can lead to development of an efficient mechanism-specific novel combination therapy that can be expedited to clinical trial in advanced ACC patients. Presentation: Saturday, June 11, 2022 1:12 p.m. - 1:17 p.m., Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

The Role of HSP90 Inhibitors in the Treatment of Cardiovascular Diseases.

Cardiovascular disease is the result of complicated pathophysiological processes in the tissues that make up the blood vessels and heart. Heat shock protein 90 (HSP90) can interact with 10% of the proteome and is the most widely studied molecular chaperone in recent years. HSP90 is extensively involved in the regulation of protein folding and intracellular protein stability, making HSP90 a hopeful target for the treatment of multiple cardiovascular diseases. Numerous client proteins of HSP90 have been identified in known cardiac disease pathways, including MAPK signaling, PI3K/AKT (PKB)/mTOR, and TNF-α signaling. Therefore, these pathways can be controlled by regulating HSP90. Among them, the activity of HSP90 can be regulated via numerous inhibitors. In this review, first, we will discuss the function of HSP90 and its role in pathological pathways. In addition, HSP90 plays a significant role in most cardiovascular diseases, including hypertension, pulmonary venous hypertension, atherosclerosis, and heart failure; next we will focus on this part. Finally, we will summarize the currently known HSP90 inhibitors and their potential in the treatment of heart disease.

Advances in research related to heat shock protein 90 and autoimmune dermatoses

Autoimmune dermatoses result from immune imbalances due to aberrant immune responses to self-antigens. Heat shock protein 90 (HSP90), as a member of a highly conserved family of stress proteins, plays an important role in inflammation and immune responses. It has been suggested that HSP90 is related to the occurrence and development of autoimmune dermatoses, but the exact mechanisms involved remain unclear. In this report, we review the evidence indicating a potential link between HSP90 and three common autoimmune dermatoses, bullous dermatoses, psoriasis and lupus erythematosus. In addition, the progress of research involving HSP90 inhibitors as potential therapeutic targets is assessed.

1 Cellular protein TTC4 and its cofactor HSP90 are pro-viral for bovine herpesvirus 1

Bovine Herpesvirus Type 1 (BoHV-1) infection causes infectious bovine rhinotracheitis and genital disease in cattle, with significant economic and welfare impacts. However, the role of cellular host factors during viral replication remains poorly characterised. A previously performed genome-wide CRISPR knockout screen identified pro- and antiviral host factors acting during BoHV-1 replication. Herein we validate a pro-viral role for a candidate from this screen: the cellular protein tetracopeptide repeat protein 4 (TTC4). We show that TTC4 transcript production is upregulated during BoHV-1 infection. Depletion of TTC4 protein impairs BoHV-1 protein production but does not reduce production of infectious virions, whereas overexpression of exogenous TTC4 results in a significant increase in production of infectious BoHV-1 virions. TTC4 itself is poorly characterized (especially in the context of virus infection), but is a known co-chaperone of heat shock protein 90 (HSP90). HSP90 has a well-characterized pro-viral role during the replication of diverse herpesviruses, and we therefore hypothesized that HSP90 is also pro-viral for BoHV-1. Drug-mediated inhibition of HSP90 using geldanamycin at sub-cytotoxic concentrations inhibited both BoHV-1 protein production and viral genome replication, indicating a pro-viral role for HSP90 during BoHV-1 infection. Our data demonstrates pro-viral roles for both TTC4 and HSP90 during BoHV-1 replication; possibly, interactions between these two proteins are required for optimal BoHV-1 replication, or the two proteins may have independent pro-viral roles.

Combination of AURKA inhibitor and HSP90 inhibitor to treat breast cancer with AURKA overexpression and TP53 mutations.

Breast cancer is the most common cancer among women worldwide. Researches show that Aurora kinase A (AURKA) is highly expressed in approximately 73% of breast cancer patients, which induces drug resistance in breast cancer patients and decreases the median survival time. AURKA regulates spindle assembly, centrosome maturation, and chromosome alignment. AURKA overexpression affects the occurrence and development of breast cancer. Besides AURKA overexpression, heat shock protein 90 (HSP90) maintains the survival and proliferation of tumor cells by stabilizing the structure of oncoproteins, including P53 mutants (mtP53). TP53 mutations accounted for approximately 13%, 40%, 80%, 33%, 71%, and 82% of luminal A, Luminal B, Luminal C, normal basal-like, HER2-amplified, and basal-like breast cancers, respectively. TP53 mutation can aggravate cell genome instability and enhance the invasion, migration, and resistance of cancer cell. This review describes the research status of AURKA and HSP90 in breast cancer, summarizes the structure, function, and the chaperone cycle of HSP90, elaborates the interrelation between HSP90, mtP53, P53, and AURKA, and proposes the combination of HSP90 inhibitor and AURKA inhibitor to treat breast cancer. Targeting AURKA and HSP90 to treat cancer with AURKA overexpression and TP53 mutations will help improve the specificity and efficiency of breast cancer treatment and solve the problem of drug resistance.

Targeting Heat-Shock Protein 90 in Cancer: An Update on Combination Therapy.

Heat-shock protein 90 (HSP90) is an important molecule chaperone associated with tumorigenesis and malignancy. HSP90 is involved in the folding and maturation of a wide range of oncogenic clients, including diverse kinases, transcription factors and oncogenic fusion proteins. Therefore, it could be argued that HSP90 facilitates the malignant behaviors of cancer cells, such as uncontrolled proliferation, chemo/radiotherapy resistance and immune evasion. The extensive associations between HSP90 and tumorigenesis indicate substantial therapeutic potential, and many HSP90 inhibitors have been developed. However, due to HSP90 inhibitor toxicity and limited efficiency, none have been approved for clinical use as single agents. Recent results suggest that combining HSP90 inhibitors with other anticancer therapies might be a more advisable strategy. This review illustrates the role of HSP90 in cancer biology and discusses the therapeutic value of Hsp90 inhibitors as complements to current anticancer therapies.

Allosteric HSP70 inhibitors perturb mitochondrial proteostasis and overcome proteasome inhibitor resistance in multiple myeloma

Proteasome inhibitor (PI) resistance remains a central challenge in multiple myeloma. To identify pathways mediating resistance, we first mapped proteasome-associated genetic co-dependencies. We identified heat shock protein 70 (HSP70) chaperones as potential targets, consistent with proposed mechanisms of myeloma cells overcoming PI-induced stress. We therefore explored allosteric HSP70 inhibitors (JG compounds) as myeloma therapeutics. JG compounds exhibited increased efficacy against acquired and intrinsic PI-resistant myeloma models, unlike HSP90 inhibition. Shotgun and pulsed SILAC mass spectrometry demonstrated that JGs unexpectedly impact myeloma proteostasis by destabilizing the 55S mitoribosome. Our data suggest JGs have the most pronounced anti-myeloma effect not through inhibiting cytosolic HSP70 proteins but instead through mitochondrial-localized HSP70, HSPA9/mortalin. Analysis of myeloma patient data further supports strong effects of global proteostasis capacity, and particularly HSPA9 expression, on PI response. Our results characterize myeloma proteostasis networks under therapeutic pressure while motivating further investigation of HSPA9 as a specific vulnerability in PI-resistant disease.

FOXM1 regulates glycolysis and energy production in multiple myeloma

The transcription factor, forkhead box M1 (FOXM1), has been implicated in the natural history and outcome of newly diagnosed high-risk myeloma (HRMM) and relapsed/refractory myeloma (RRMM), but the mechanism with which FOXM1 promotes the growth of neoplastic plasma cells is poorly understood. Here we show that FOXM1 is a positive regulator of myeloma metabolism that greatly impacts the bioenergetic pathways of glycolysis and oxidative phosphorylation (OxPhos). Using FOXM1-deficient myeloma cells as principal experimental model system, we find that FOXM1 increases glucose uptake, lactate output, and oxygen consumption in myeloma. We demonstrate that the novel 1,1-diarylethylene small-compound FOXM1 inhibitor, NB73, suppresses myeloma in cell culture and human-in-mouse xenografts using a mechanism that includes enhanced proteasomal FOXM1 degradation. Consistent with the FOXM1-stabilizing chaperone function of heat shock protein 90 (HSP90), the HSP90 inhibitor, geldanamycin, collaborates with NB73 in slowing down myeloma. These findings define FOXM1 as a key driver of myeloma metabolism and underscore the feasibility of targeting FOXM1 for new approaches to myeloma therapy and prevention.

Therapeutic Response Monitoring with 89Zr-DFO-Pertuzumab in HER2-Positive and Trastuzumab-Resistant Breast Cancer Models.

Immuno-positron emission tomography (PET) has great potential to evaluate the target expression level and therapeutic response for targeted cancer therapy. Immuno-PET imaging with pertuzumab, due to specific recognition in different binding sites of HER2, could be useful for the determination of the therapeutic efficacy of HER2-targeted therapy, trastuzumab, and heat shock protein 90 (HSP90) inhibitor, in HER2-expressing breast cancer. The aim of this study is to evaluate the feasibility of monitoring therapeutic response with 89Zr-DFO-pertuzumab for the treatment of HER2-targeted therapeutics, trastuzumab, or the HSP90 inhibitor 17-DMAG, in trastuzumab-resistant JIMT-1 breast cancer models. We prepared an immuno-PET imaging agent using desferoxamine (DFO)-pertuzumab labeled with 89Zr and performed the biodistribution and PET imaging in breast cancer xenograft models for monitoring therapeutic response to HER2-targeted therapy. 89Zr-DFO-pertuzumab was successfully prepared and showed specific binding to HER2 in vitro and clearly visualized HER2 expressing JIMT-1 tumors. 89Zr-DFO-pertuzumab had prominent tumor uptake in HER2 expressing JIMT-1 tumors. JIMT-1 tumors showed trastuzumab-resistant and HSP90 inhibitor sensitive characterization. In immuno-PET imaging, isotype antibody-treated JIMT-1 tumors had similar uptake in trastuzumab-treated JIMT-1 tumors, but 17-DMAG-treated JIMT-1 tumors showed greatly reduced uptake compared to vehicle-treated tumors. Additionally, HER2 downregulation evaluated by immuno-PET imaging was verified by western blot analysis and immunofluorescence staining which resulted in a significant reduction in the tumor’s HER2 level in 17-DMAG-treated JIMT-1 tumors. 89Zr-DFO-pertuzumab immuno-PET may be clinically translated to select pertinent patients for HER2-targeted therapy and to monitor the therapeutic response in HER2-positive cancer patients under various HER2-targeted therapeutics treatments.

S153: DECRYPTING THE ROLE OF HSP90Α AND Β ISOFORMS TO OVERCOME RESISTANCE IN BCR-ABL1 LEUKEMIA

Background: The BCR-ABL1 fusion protein, which results from the chromosomal translocation t(9;22)(q34;q11) is detected in over 95% of CML, 25% of adult BCP-ALL and 3-5% of childhood BCP-ALL patients. The development of tyrosine kinase inhibitors (TKi) has enabled targeted treatment, however development of resistance is common and the BCR-ABL1 leukemia subtype is still associated with poor prognosis. Among the chaperone proteins involved in maintaining the homeostasis of cancerous cells, heat shock protein 90 (HSP90) have been widely studied, due to its crucial involvement in stabilizing a variety of oncogenic proteins, including BCR-ABL1 and STAT3/5. Therefore, inhibition of HSP90 can be an effective alternative approach to target TKi resistant and BCR-ABL1T315I mutant expressing cells. In the past, over 17 HSP90 inhibitors (HSP90i) have been evaluated in clinical trials, however associated resistances (e.g. HSR) and dose limited toxicity have thus far precluded their clinical approval. Aims: In mammalian cells, there are two predominant cytosolic isoforms of HSP90, a stress-inducible HSP90α and a constitutively expressed HSP90β isoform. In the past, the distinct roles of the isoforms were studied by applying pan- and isoform-targeted HSP90i. We aimed to decrypt the role of cytosolic HSP90 isoforms using genetically edited models and to identify novel therapeutic vulnerabilities to target therapy refractory BCR-ABL1+ leukemia. Methods: To study the kinetic implications of the resistance mechanism associated with pharmacological targeting of HSP90, we generated a transient knockdown (Kd) and a stable CRISPR-Cas9 based knockout (KO) model of HSP90α/β in BCR-ABL1+ cells. The edited cells were analyzed in ex vivo functional assays (e.g. IF staining and WB) and their transplantation efficiency was determined in NSG mice. Global transcriptomic and proteomic profiling was performed in conjunction with high throughput drug screening (HTDS) to identify therapeutic vulnerabilities upon loss of HSP90α/β. Results: HSP90α/β-KO or -Kd did not affect the expression of other HSP90 paralogues (TRAP1 and GRP94). Only HSP90β-KO cells displayed hyperactive pro-survival HSR. Other reported HSP90 isoform-dependent clients, such as Survivin, CDK4 and CDK6 were also not affected upon KO or Kd of HSP90α/β. As HSP90 is involved in stabilizing, proper folding and subcellular localization of BCR-ABL1 protein, immunofluorescence imaging demonstrated two fold higher abundance of BCR-ABL1 foci (cytoplasmic/nucleocytoplasmic region) in HSP90α KO cells, with hyperactive BCR-ABL1 and downstream signaling (pBCR-ABL and pSTAT5a). When KO cells were transplanted into NSG mice (n=5 mice per arm) the engraftment of the HSP90α-KO cells was significantly reduced with a prolonged overall survival of the animals (19 days, p=0.0083) as compared to HSP90β-KO and control group. To find possible target (s) in order to circumvent resistance associated with the use HSP90i, we performed HTDS with HSP90α/β KO cells, which revealed distinct sensitivities toward certain classes of inhibitors. One of these classes was CDK7i, which was differentially active in HSP90α KO cells. These results can be explained by our global transcriptomic results, which revealed hyperactive androgen receptor signaling in HSP90α KO cells (GSEA), which is known to be a prognostic marker for CDK7 inhibition. Summary/Conclusion: In vivo targeting of HSP90α is a promising approach to target BCR-ABL1+ leukemia cells. Moreover, the combination with CDK7i may help to overcome the resistance associated with clinical use of pan HSP90i.

HSP90 and Aha1 modulate microRNA maturation through promoting the folding of Dicer1.

Aha1 is a co-chaperone of heat shock protein 90 (HSP90), and it stimulates the ATPase activity of HSP90 to promote the folding of its client proteins. By employing ascorbate peroxidase (APEX)-based proximity labeling and proteomic analysis, we identified over 30 proteins exhibiting diminished abundances in the proximity proteome of HSP90 in HEK293T cells upon genetic depletion of Aha1. Dicer1 is a top-ranked protein, and we confirmed its interactions with HSP90 and Aha1 by immunoprecipitation followed by western blot analysis. Genetic depletion of Aha1 and pharmacological inhibition of HSP90 both led to reduced levels of Dicer1 protein. Additionally, HSP90 and Aha1 bind preferentially to newly translated Dicer1. Reconstitution of Aha1-depleted cells with wild-type Aha1 substantially rescued Dicer1 protein level, and a lower level of restoration was observed for complementation with the HSP90-binding-defective Aha1-E67K, whereas an Aha1 mutant lacking the first 20 amino acids—which abolishes its chaperone activity—failed to rescue Dicer1 protein level. Moreover, knockdown of Aha1 and inhibition of HSP90 led to diminished levels of mature microRNAs (miRNAs), but not their corresponding primary miRNAs. Together, we uncovered a novel mechanism of HSP90 and Aha1 in regulating the miRNA pathway through promoting the folding of Dicer1 protein, and we also demonstrated that Aha1 modulates this process by acting as an autonomous chaperone and a co-chaperone for HSP90.

Novel Drugs with High Efficacy against Tumor Angiogenesis.

Angiogenesis is involved in physiological and pathological processes in the body. Tumor angiogenesis is a key factor associated with tumor growth, progression, and metastasis. Therefore, there is great interest in developing antiangiogenic strategies. Hypoxia is the basic initiating factor of tumor angiogenesis, which leads to the increase of vascular endothelial growth factor (VEGF), angiopoietin (Ang), hypoxia-inducible factor (HIF-1), etc. in hypoxic cells. The pathways of VEGF and Ang are considered to be critical steps in tumor angiogenesis. A number of antiangiogenic drugs targeting VEGF/VEGFR (VEGF receptor) or ANG/Tie2, or both, are currently being used for cancer treatment, or are still in various stages of clinical development or preclinical evaluation. This article aims to review the mechanisms of angiogenesis and tumor angiogenesis and to focus on new drugs and strategies for the treatment of antiangiogenesis. However, antitumor angiogenic drugs alone may not be sufficient to eradicate tumors. The molecular chaperone heat shock protein 90 (HSP90) is considered a promising molecular target. The VEGFR system and its downstream signaling molecules depend on the function of HSP90. This article also briefly introduces the role of HSP90 in angiogenesis and some HSP90 inhibitors.

Abstract 3712: The C-terminal HSP90 inhibitor, a novel deguelin derivative, exerts anti-metastatic effects in triple-negative breast cancer by targeting cancer stem-like properties

Abstract Purpose: Triple-negative breast cancer (TNBC) still relies on non-selective cytotoxic anticancer agents due to the absence of established molecular targets for the phenotype. The heat shock protein 90 (HSP90) is a promising therapeutic target because it affects the overall progression of cancer, including cell proliferation, angiogenesis and metastasis. A variety of N-terminal HSP90 inhibitors have been tried several times in clinical trials, but none have been approved for clinical use to date due to issues including heat shock response (HSR) induction, undesirable effects, and clinical toxicity. In this study, we sought to investigate whether a novel C-terminal HSP90 inhibitor SL-145 could resolve metastasis in TNBC through inhibition of cancer stem-like properties. Experimental Design: The effects of SL-145 on TNBC cell lines in vitro were evaluated in terms of cell proliferation, apoptosis, caspase-3 activity, breast cancer stem cell (BCSC)-like properties and heat shock response. An orthotopic allograft model with 4T1 mammospheres was used to examine the effect of SL-145 on tumor growth and metastasis in vivo. Results: SL-145 induces apoptosis without triggering the HSR and simultaneously inhibits several oncogenic signaling pathways including AKT, MEK/ERK and JAK2/STAT3. SL-145 effectively targets BCSC-like properties with significant reductions in CD44, CD49f and ALDH1 expression as well as impairment of mammosphere-forming ability. To confirm the physiological relevance of our in vitro observations, we investigated the effects of SL-145 on tumor growth, angiogenesis and metastasis in mammosphere-derived allograft tumors with self-renewal capacity. SL-145 administration reduced tumor burden and angiogenesis, which were enriched in BCSCs, and it resulted in significant reductions in lung and liver metastases. In addition, no toxic effects of inhibitors on markers of liver or renal function were observed. Conclusion: Our findings suggest that SL-145 may represent an effective therapeutic approach for targeting cancer stem cells and simultaneous inhibition of the HSP90 client oncoprotein to treat TNBC with a heterogeneous and aggressive nature. Citation Format: Minsu Park, Tae-Min Cho, Soeun Park, Jung Min Park, Juyeon Seo, Dongmi Ko, Seongjae Kim, So Ra Seuk, Yong Gu Kang, Kee Dal Nam, Yoon-Jae Kim, Ji Young Kim, Jae Hong Seo. The C-terminal HSP90 inhibitor, a novel deguelin derivative, exerts anti-metastatic effects in triple-negative breast cancer by targeting cancer stem-like properties [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3712.

Heat Shock Protein 90's Mechanistic Role in Contact Hypersensitivity.

Despite the known dangers of contact allergens and their long-lasting use as models in immunology, their molecular mode of action largely remains unknown. In this study, we report that a contact allergen, 1-chloro-2,4-dinitrobenzene (DNCB), elicits contact hypersensitivity through binding the protein we identify. Starting from an unbiased sampling of proteomics, we found nine candidate proteins with unique DNCB-modified peptide fragments. More than half of these fragments belonged to heat shock protein 90 (HSP90), a common stress-response protein and a damage-associated molecular pattern, and showed the highest probability of incidence. Inhibition and short hairpin RNA knockdown of HSP90 in human monocyte cell line THP-1 suppressed the potency of DNCB by >80%. Next, we successfully reduced DNCB-induced contact hypersensitivity in HSP90-knockout mice, which confirmed our findings. Finally, we hypothesized that DNCB-modified HSP90 activates the immune cells through HSP90's receptor, CD91. Pretreatment of CD91 in THP-1 cell lines and BALB/c mice attenuated the potency of DNCB, consistent with the result of HSP90-knockout mice. Altogether, our data show that DNCB-HSP90 binding plays a role in mediating DNCB-induced contact hypersensitivity, and the activation of CD91 by DNCB-modified HSP90 proteins could mediate this process.

Heat Shock Protein 90 (HSP90) Inhibitors as Anticancer Medicines: A Review on the Computer-Aided Drug Discovery Approaches over the Past Five Years.

Cancer is a disease caused by the uncontrolled, abnormal growth of cells in different anatomic sites. In 2018, it was predicted that the worldwide cancer burden would rise to 18.1 million new cases and 9.6 million deaths. Anticancer compounds, often known as chemotherapeutic medicines, have gained much interest in recent cancer research. These medicines work through various biological processes in targeting cells at various stages of the cell's life cycle. One of the most significant roadblocks to developing anticancer drugs is that traditional chemotherapy affects normal cells and cancer cells, resulting in substantial side effects. Recently, advancements in new drug development methodologies and the prediction of the targeted interatomic and intermolecular ligand interaction sites have been beneficial. This has prompted further research into developing and discovering novel chemical species as preferred therapeutic compounds against specific cancer types. Identifying new drug molecules with high selectivity and specificity for cancer is a prerequisite in the treatment and management of the disease. The overexpression of HSP90 occurs in patients with cancer, and the HSP90 triggers unstable harmful kinase functions, which enhance carcinogenesis. Therefore, the development of potent HSP90 inhibitors with high selectivity and specificity becomes very imperative. The activities of HSP90 as chaperones and cochaperones are complex due to the conformational dynamism, and this could be one of the reasons why no HSP90 drugs have made it beyond the clinical trials. Nevertheless, HSP90 modulations appear to be preferred due to the competitive inhibition of the targeted N-terminal adenosine triphosphate pocket. This study, therefore, presents an overview of the various computational models implored in the development of HSP90 inhibitors as anticancer medicines. We hereby suggest an extensive investigation of advanced computational modelling of the three different domains of HSP90 for potent, effective inhibitor design with minimal off-target effects.

Investigation of the Role of Wnt/Delta‐Catenin Signaling in Regulating Opioid Pain Relief After Heat Shock Protein 90 Inhibition

Opioid receptors are important regulators of pain, and opioid drugs like morphine are used in a wide variety of clinical settings throughout the world. In spite of their clear utility and efficacy concerning the treatment of pain, the addictive nature of opioids limits their use as an option for the treatment of chronic pain. This illustrates the great medical and social need to improve opioid therapy, both enhancing analgesia and reducing side effects like addiction. More recently, we showed that Heat shock protein 90 (HSP90), a molecular chaperone that participates in a vast array of critical molecular processes in the cell, has been implicated as an important modulator of opioid‐induced pain relief within the spinal cord. We found that inhibition of HSP90 improved the therapeutic index of opioids, boosting pain relief and reducing side effects. In an effort to elucidate the molecular pathways responsible for these benefits, we performed proteomic analysis of spinal cord tissue from male and female CD‐1 mice treated with intrathecal Vehicle or 17‐AAG (0.5 nmol, 24 hrs), an HSP90 inhibitor. We found that the signaling molecule delta‐catenin2 was reduced by 27.6% by 17‐AAG treatment in spinal tissue. Since delta‐catenin2 stabilizes and enables Wnt signaling, this suggests that Wnt signaling is also reduced by HSP90 inhibition. As Wnt has been shown to promote pain, this fits with our model that suppressed Wnt/Catenin signaling could enhance opioid pain relief after HSP90 inhibition. We thus report here our efforts to test this hypothesis by using a Wnt activator (AMBMP) and Wnt inhibitor (JW74) combined with 17‐AAG and morphine in a mouse tail flick pain model; we also report our efforts to confirm molecular Wnt signaling changes in spinal cord by Western Blot and qPCR for Wnt itself along with established Wnt signaling targets VEGF‐A and LEF1. Together these studies will establish a new mechanistic node linking HSP90 to the regulation of opioid pain relief in the spinal cord. This will enhance our basic science understanding of this system and could lead to novel therapeutic targets.