Silmitasertib (CX-4945) Disrupts ERα/HSP90 Interaction and Drives Proteolysis through the Disruption of CK2ß Function in Breast Cancer Cells.

Aberrant estrogen receptor (ERα) signaling mediates detrimental effects of tamoxifen including drug resistance and endometrial hyperplasia. ERα36, an alternative isoform of ERα, contributes to these effects. We have demonstrated that CK2 modulates ERα expression and function in breast cancer (BCa). Here, we assess if CX-4945 (CX), a clinical stage CK2 inhibitor, can disrupt ERα66 and ERα36 signaling in BCa. Using live cell imaging, we assessed the antiproliferative effects of CX in tamoxifen-sensitive and tamoxifen-resistant BCa cells in monolayer and/or spheroid cultures. CX-induced alterations in ERα66 and ERα36 mRNA and protein expression were assessed by RT-PCR and immunoblot. Co-immunoprecipitation was performed to determine the differential interaction of ERα isoforms with HSP90 and CK2 upon CX exposure. CX caused concentration-dependent decreases in proliferation in tamoxifen-sensitive MCF-7 and tamoxifen-resistant MCF-7 Tam1 cells and significantly repressed spheroid growth in 3D models. Additionally, CX caused dramatic decreases in endogenous or exogenously expressed ERα66 and ERα36 protein. Silencing of CK2ß, the regulatory subunit of CK2, resulted in destabilization and decreased proliferation, similar to CX. Co-immunoprecipitation demonstrated that ERα66/36 show CK2 dependance for interaction with molecular chaperone HSP90. Our findings show that CK2 functions regulate the protein stability of ERα66 and ERα36 through a mechanism that is dependent on CK2ß subunit and HSP90 chaperone function. CX may be a component of a novel therapeutic strategy that targets both tamoxifen-sensitive and tamoxifen-resistant BCa, providing an additional tool to treat ERα-positive BCa.

Molecular pathway of anticancer effect of next-generation HSP90 inhibitors XL-888 and Debio0932 in neuroblastoma cell line.

Neuroblastoma is a common nervous system tumor in childhood, and current treatments are not adequate. HSP90 is a molecular chaperone protein that plays a critical role in the regulation of cancer-related proteins. HSP90 inhibition may exert anticancer effects by targeting cancer-related processes such as tumor growth, cell proliferation, metastasis, and apoptosis. Therefore, HSP90 inhibition is a promising strategy in the treatment of various types of cancer, and the development of next-generation inhibitors could potentially lead to more effective and safer treatments. XL-888 and Debio0932 is a next-generation HSP90 inhibitor and can inhibit the correct folding and stabilization of client proteins that cancer-associated HSP90 helps to fold correctly. In this study, we aimed to investigate the comprehensive molecular pathways of the anticancer activity of XL-888 and Debio0932 in human neuroblastoma cells SH-SY5Y. The cytotoxic effects of XL-888 and Debio0932 on the neuroblastoma cell line SH-SY5Y cells were evaluated by MTT assay. Then, the effect of these HSP90 inhibitors on the expression of important genes in cancer was revealed by Quantitative Real Time Polymerase Chain Reaction (qRT-PCR) method. The qRT-PCR data were evaluated using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) biological process tools. Finally, the effect of HSP90 inhibitors on HSP27, HSP70 and HSP90 protein expression was investigated by Western blotting analysis. The results revealed that XL-888 and Debio0932 had a role in regulating many cancer-related pathways such as migration, invasion, metastasis, angiogenesis, and apoptosis in SH-SY5Y cells. In conclusion, it shows that HSP90 inhibitors can be considered as a promising candidate in the treatment of neuroblastoma and resistance to chemotherapy.

Maturation and Assembly of mTOR Complexes by the HSP90-R2TP-TTT Chaperone System: Molecular Insights and Mechanisms.

The mechanistic target of rapamycin (mTOR) is a master regulator of cell growth and metabolism, integrating environmental signals to regulate anabolic and catabolic processes, regulating lipid synthesis, growth factor-induced cell proliferation, cell survival, and migration. These activities are performed as part of two distinct complexes, mTORC1 and mTORC2, each with specific roles. mTORC1 and mTORC2 are elaborated dimeric structures formed by the interaction of mTOR with specific partners. mTOR functions only as part of these large complexes, but their assembly and activation require a dedicated and sophisticated chaperone system. mTOR folding and assembly are temporarily separated with the TELO2-TTI1-TTI2 (TTT) complex assisting the cotranslational folding of mTOR into a native conformation. Matured mTOR is then transferred to the R2TP complex for assembly of active mTORC1 and mTORC2 complexes. R2TP works in concert with the HSP90 chaperone to promote the incorporation of additional subunits to mTOR and dimerization. This review summarizes our current knowledge on how the HSP90-R2TP-TTT chaperone system facilitates the maturation and assembly of active mTORC1 and mTORC2 complexes, discussing interactions, structures, and mechanisms.

Elucidating molecular mechanism and chemical space of chalcones through biological networks and machine learning approaches.

We developed a bio-cheminformatics method, exploring disease inhibition mechanisms using machine learning-enhanced quantitative structure-activity relationship (ML-QSAR) models and knowledge-driven neural networks. ML-QSAR models were developed using molecular fingerprint descriptors and the Random Forest algorithm to explore the chemical spaces of Chalcones inhibitors against diverse disease properties, including antifungal, anti-inflammatory, anticancer, antimicrobial, and antiviral effects. We generated and validated robust machine learning-based bioactivity prediction models (https://github.com/RatulChemoinformatics/QSAR) for the top genes. These models underwent ROC and applicability domain analysis, followed by molecular docking studies to elucidate the molecular mechanisms of the molecules. Through comprehensive neural network analysis, crucial genes such as AKT1, HSP90AA1, SRC, and STAT3 were identified. The PubChem fingerprint-based model revealed key descriptors: PubchemFP521 for AKT1, PubchemFP180 for SRC, PubchemFP633 for HSP90AA1, and PubchemFP145 and PubchemFP338 for STAT3, consistently contributing to bioactivity across targets. Notably, chalcone derivatives demonstrated significant bioactivity against target genes, with compound RA1 displaying a predictive pIC50 value of 5.76 against HSP90AA1 and strong binding affinities across other targets. Compounds RA5 to RA7 also exhibited high binding affinity scores comparable to or exceeding existing drugs. These findings emphasize the importance of knowledge-based neural network-based research for developing effective drugs against diverse disease properties. These interactions warrant further in vitro and in vivo investigations to elucidate their potential in rational drug design. The presented models provide valuable insights for inhibitor design and hold promise for drug development. Future research will prioritize investigating these molecules for mycobacterium tuberculosis, enhancing the comprehension of effectiveness in addressing infectious diseases.

HOP stabilizes the HSFA1a and plays a main role in the onset of thermomorphogenesis.

Living organisms have the capacity to respond to environmental stimuli, including warm conditions. Upon sensing mild temperature, plants launch a transcriptional response that promotes morphological changes, globally known as thermomorphogenesis. This response is orchestrated by different hormonal networks and by the activity of different transcription factors, including the heat shock factor A1 (HSFA1) family. Members of this family interact with heat shock protein 70 (HSP70) and heat shock protein 90 (HSP90); however, the effect of this binding on the regulation of HSFA1 activity or of the role of cochaperones, such as the HSP70-HSP90 organizing protein (HOP) on HSFA1 regulation, remains unknown. Here, we show that AtHOPs are involved in the folding and stabilization of the HSFA1a and are required for the onset of the transcriptional response associated to thermomorphogenesis. Our results demonstrate that the three members of the AtHOP family bind in vivo to the HSFA1a and that the expression of multiple HSFA1a-responsive-responsive genes is altered in the hop1 hop2 hop3 mutant under warm temperature. Interestingly, HSFA1a is accumulated at lower levels in the hop1 hop2 hop3 mutant, while control levels are recovered in the presence of the proteasome inhibitor MG132 or the synthetic chaperone tauroursodeoxycholic acid (TUDCA). This uncovers the HSFA1a as a client of HOP complexes in plants and reveals the participation of HOPs in HSFA1a stability.

Miconazole induces aneuploidy-mediated tolerance in Candida albicans that is dependent on Hsp90 and calcineurin.

Antifungal resistance and antifungal tolerance are two distinct terms that describe different cellular responses to drugs. Antifungal resistance describes the ability of a fungus to grow above the minimal inhibitory concentration (MIC) of a drug. Antifungal tolerance describes the ability of drug susceptible strains to grow slowly at inhibitory drug concentrations. Recent studies indicate antifungal resistance and tolerance have distinct evolutionary trajectories. Superficial candidiasis bothers millions of people yearly. Miconazole has been used for topical treatment of yeast infections for over 40 years. Yet, fungal resistance to miconazole remains relatively low. Here we found different clinical isolates of Candida albicans had different profile of tolerance to miconazole, and the tolerance was modulated by physiological factors including temperature and medium composition. Exposure of non-tolerant strains with different genetic backgrounds to miconazole mainly induced development of tolerance, not resistance, and the tolerance was mainly due to whole chromosomal or segmental amplification of chromosome R. The efflux gene CDR1 was required for maintenance of tolerance in wild type strains but not required for gain of aneuploidy-mediated tolerance. Heat shock protein Hsp90 and calcineurin were essential for maintenance as well as gain of tolerance. Our study indicates development of aneuploidy-mediated tolerance, not resistance, is the predominant mechanism of rapid adaptation to miconazole in C. albicans, and the clinical relevance of tolerance deserves further investigations.

Cardiovascular safety of pimitespib in patients with advanced solid tumors: An open-label, nonrandomized, phase 1 study.

BACKGROUND: Pimitespib (TAS-116), a first-in-class, oral, selective heat-shock protein 90 inhibitor, is approved as fourth-line treatment for gastrointestinal stromal tumors in Japan. This phase 1 study evaluated the cardiac safety of pimitespib. METHODS: In this open-label, nonrandomized, multicenter study, Japanese patients (aged ≥20 years) with refractory, advanced solid tumors received placebo on day -1, then pimitespib 160 mg daily on days 1-5 of the cardiac safety evaluation period. Electrocardiograms were conducted at baseline, and on days -2, -1, 1, and 5; and blood samples were collected on days 1 and 5. Patients then received once-daily pimitespib for 5 days every 3 weeks. The primary end point was the time-matched difference in QT interval corrected for heart rate using the Fridericia correction (QTcF) between pimitespib and placebo. Pharmacokinetics, safety, and preliminary efficacy were also assessed. RESULTS: Of the 22 patients in the cardiac safety-evaluable population, no clinically relevant QTc prolongation was observed; the upper bound of the one-sided 95% confidence interval for the time-matched difference in change from baseline in QTcF was <20 msec at all time points on days 1 and 5. Pimitespib pharmacokinetic parameters were consistent with previous data, and the time-matched difference in change from baseline in QTcF showed no marked increase as plasma concentrations increased. The safety profile was acceptable; 40% of patients experienced grade 3 or greater adverse drug reactions, mostly diarrhea (20%). The median progression-free survival was 3.1 months. CONCLUSIONS: In Japanese patients with refractory, advanced solid tumors, pimitespib was not associated with clinically relevant QTc prolongation, and there were no cardiovascular safety concerns. PLAIN LANGUAGE SUMMARY: Pimitespib is a new anticancer drug that is being used to treat cancer in the stomach or intestines (gastrointestinal stromal tumors). This study demonstrated that pimitespib had no marked effect on heart rhythm or negative effects on the heart or blood vessels and had promising anticancer effects in Japanese patients with advanced solid tumors who were unable to tolerate or benefit from standard treatment.

Development of a Humanized Antibody Targeting Extracellular HSP90α to Suppress Endothelial-Mesenchymal Transition-Enhanced Tumor Growth of Pancreatic Adenocarcinoma Cells.

Extracellular HSP90α (eHSP90α) is a promoter of tumor development and malignant progression. Patients with malignancies, including pancreatic ductal adenocarcinoma (PDAC), have generally shown 5~10-fold increases in serum/plasma eHSP90α levels. In this study, we developed a humanized antibody HH01 to target eHSP90α and evaluated its anticancer efficacy. HH01, with novel complementarity-determining regions, exhibits high binding affinity toward HSP90α. It recognizes HSP90α epitope sites 235AEEKEDKEEE244 and 251ESEDKPEIED260, with critical amino acid residues E237, E239, D240, K241, E253, and K255. HH01 effectively suppressed eHSP90α-induced invasive and spheroid-forming activities of colorectal cancer and PDAC cell lines by blocking eHSP90α's ligation with the cell-surface receptor CD91. In mouse models, HH01 potently inhibited the tumor growth of PDAC cell grafts/xenografts promoted by endothelial-mesenchymal transition-derived cancer-associated fibroblasts while also reducing serum eHSP90α levels, reflecting its anticancer efficacy. HH01 also modulated tumor immunity by reducing M2 macrophages and reinvigorating immune T-cells. Additionally, HH01 showed low aggregation propensity, high water solubility, and a half-life time of >18 days in mouse blood. It was not cytotoxic to retinal pigmented epithelial cells and showed no obvious toxicity in mouse organs. Our data suggest that targeting eHSP90α with HH01 antibody can be a promising novel strategy for PDAC therapy.

Plastid HSP90C C-terminal extension region plays a regulatory role in chaperone activity and client binding.

HSP90Cs are essential molecular chaperones localized in the plastid stroma that maintain protein homeostasis and assist the import and thylakoid transport of chloroplast proteins. While HSP90C contains all conserved domains as an HSP90 family protein, it also possesses a unique feature in its variable C-terminal extension (CTE) region. This study elucidated the specific function of this HSP90C CTE region. Our phylogenetic analyses revealed that this intrinsically disordered region contains a highly conserved DPW motif in the green lineages. With biochemical assays, we showed that the CTE is required for the chaperone to effectively interact with client proteins PsbO1 and LHCB2 to regulate ATP-independent chaperone activity and to effectuate its ATP hydrolysis. The CTE truncation mutants could support plant growth and development reminiscing the wild type under normal conditions except for a minor phenotype in cotyledon when expressed at a level comparable to wild type. However, higher HSP90C expression was observed to correlate with a stronger response to specific photosystem II inhibitor DCMU, and CTE truncations dampened the response. Additionally, when treated with lincomycin to inhibit chloroplast protein translation, CTE truncation mutants showed a delayed response to PsbO1 expression repression, suggesting its role in chloroplast retrograde signaling. Our study therefore provides insights into the mechanism of HSP90C in client protein binding and the regulation of green chloroplast maturation and function, especially under stress conditions.

Discovery of indazole inhibitors for heat shock protein 90 as anti-cancer agents.

A series of indazole analogs, derived from the B,C-ring-truncated scaffold of deguelin, were designed to function as C-terminal inhibitors of heat shock protein 90 (HSP90) and investigated as novel antitumor agents against HER2-positive breast cancer. Among the synthesized compounds, compound 12d exhibited substantial inhibitory effects in trastuzumab-sensitive (BT474) and trastuzumab-resistant (JIMT-1) breast cancer cells, with IC50 values of 6.86 and 4.42 µM, respectively. Notably, compound 12d exhibited no cytotoxicity in normal cells. Compound 12d markedly downregulated the expression of the major HSP90 client proteins in both cell types, attributing its cytotoxicity to the destabilization and inactivation of HSP90 client proteins. Molecular docking studies using the homology model of an HSP90 homodimer demonstrated that inhibitor 12d fit nicely into the C-terminal domain, boasting a higher electrostatic complementary score than ATP. In vivo pharmacokinetic study indicated the high oral bioavailability of compound 12 d at F = 66.9 %, while toxicological studies indicated its negligible impact on hERG channels and CYP isozymes. Genotoxicity tests further confirmed its safety profile. The findings collectively position compound 12d as a promising candidate for further development as an antitumor agent against HER2-positive breast cancer.

Identification and biological evaluation of fused tetrahydroisoquinoline derivatives as Wnt/ß-catenin signaling inhibitors to suppress colorectal cancer.

Colorectal cancer (CRC) has been becoming one of the most common causes of cancer mortality worldwide. Accumulating studies suggest that the progressive up-regulation of Wnt/ß-catenin signaling is a crucial hallmark of CRC, and suppressing it is a promising strategy to treat CRC. Herein, we reported our latest efforts in the discovery of novel fused tetrahydroisoquinoline derivatives with good anti-CRC activities by screening our in-house berberine-like library and further structure-activity relationship (SAR) studies, in which we identified compound 10 is a potent lead compound with significant antiproliferation potencies. By the biotinylated probe and LC-MS/MS study, Hsp90 was identified as its molecular target, which is a fully different mechanism of action from what we reported before. Further studies showed compound 10 directly engaged the N-terminal site of Hsp90 and promoted the degradation of ß-catenin, thereby suppressing the Wnt/ß-catenin signaling. More importantly, compound 10 exhibits favorable pharmacokinetic parameters and significant anti-tumor efficacies in the HCT116 xenograft model. Taken together, this study furnished the discovery of candidate drug compound 10 possessing a novel fused tetrahydroisoquinoline scaffold with excellent in vitro and in vivo anti-CRC activities by targeting Hsp90 to disturb Wnt/ß-catenin signaling pathway, which lay a foundation for discovering more effective CRC-targeted therapies.

Unleashing the Neurotherapeutic Potential: The Crucial Role of miR-206-3p in Facilitating Hsp90aa1-Mediated Central Nervous System Injuries During Heat Stroke.

This study aims to explore the molecular mechanisms of miR-206-3p in regulating Hsp90aa1 and its involvement in the central nervous system (CNS) injury in heat stroke. Weighted gene co-expression network analysis (WGCNA) was performed on the GSE64778 dataset of heat stroke to identify module genes most closely associated with disease characteristics. Through the selection of key genes and predicting upstream miRNAs using RNAInter and miRWalk databases, the regulatory relationship between miR-206-3p and Hsp90aa1 was determined. Through in vitro experiments, various methods, including bioinformatics analysis, dual-luciferase reporter gene assay, RIP experiment, and RNA pull-down experiment, were utilized to validate this regulatory relationship. Furthermore, functional experiments, including CCK-8 assay to test neuron cell viability and flow cytometry to assess neuron apoptosis levels, confirmed the role of miR-206-3p. Transmission electron microscopy, real-time quantitative PCR, DCFH-DA staining, and ATP assay were employed to verify neuronal mitochondrial damage. Heat stroke rat models were constructed, and mNSS scoring and cresyl violet staining were utilized to assess neural functional impairment. Biochemical experiments were conducted to evaluate inflammation, brain water content, and histopathological changes in brain tissue using H&E staining. TUNEL staining was applied to detect neuronal apoptosis in brain tissue. RT-qPCR and Western blot were performed to measure gene and protein expression levels, further validating the regulatory relationship in vivo. Bioinformatics analysis indicated that miR-206-3p regulation of Hsp90aa1 may be involved in CNS injury in heat stroke. In vivo, animal experiments demonstrated that miR-206-3p and Hsp90aa1 co-localized in neurons of the rat hippocampal CA3 region, and with prolonged heat stress, the expression of miR-206-3p gradually increased while the expression of Hsp90aa1 gradually decreased. Further in vitro cellular mechanism validation and functional experiments confirmed that miR-206-3p could inhibit neuronal cell viability and promote apoptosis and mitochondrial damage by targeting Hsp90aa1. In vivo, experiments confirmed that miR-206-3p promotes CNS injury in heat stroke. This study revealed the regulatory relationship between miR-206-3p and Hsp90aa1, suggesting that miR-206-3p could regulate the expression of Hsp90aa1, inhibit neuronal cell viability, and promote apoptosis, thereby contributing to CNS injury in heat stroke.

Investigation of the site 2 pocket of Grp94 with KUNG65 benzamide derivatives.

Glucose-regulated protein 94 (Grp94) is an isoform of the heat shock protein 90 kDa (Hsp90) family of molecular chaperones. Inhibiting Grp94 has been implicated for many diseases. Co-crystal structures of two generations of Grp94 inhibitors revealed the importance of investigating the ester group, which is projected into the site 2 pocket unique to Grp94. Therefore, a series of KUNG65 benzamide analogs was designed and synthesized to evaluate their impact on the affinity and selectivity for Grp94. The data demonstrated that substituents with small and saturated ring systems that contain hydrogen bond acceptors exhibited increased affinity for Grp94, whereas larger saturated ring system manifested increased selectivity for Grp94 over Hsp90α.

SENP1-Mediated HSP90ab1 DeSUMOylation in Cardiomyocytes Prevents Myocardial Fibrosis by Paracrine Signaling.

Myocardial infarction (MI) triggers a poor ventricular remodeling response, but the underlying mechanisms remain unclear. Here, the authors show that sentrin-specific protease 1 (SENP1) is downregulated in post-MI mice and in patients with severe heart failure. By generating cardiomyocyte-specific SENP1 knockout and overexpression mice to assess cardiac function and ventricular remodeling responses under physiological and pathological conditions. Increased cardiac fibrosis in the cardiomyocyte-specific SENP1 deletion mice, associated with increased fibronectin (Fn) expression and secretion in cardiomyocytes, promotes fibroblast activation in response to myocardial injury. Mechanistically, SENP1 deletion in mouse cardiomyocytes increases heat shock protein 90 alpha family class B member 1 (HSP90ab1) SUMOylation with (STAT3) activation and Fn secretion after ventricular remodeling initiated. Overexpression of SENP1 or mutation of the HSP90ab1 Lys72 ameliorates adverse ventricular remodeling and dysfunction after MI. Taken together, this study identifies SENP1 as a positive regulator of cardiac repair and a potential drug target for the treatment of MI. Inhibition of HSP90ab1 SUMOylation stabilizes STAT3 to inhibit the adverse ventricular remodeling response.

Arsenite treatment induces Hsp90 aggregatesdistinct from conventional stress granules in fission yeast.

Various stress conditions, such as heat stress (HS) and oxidative stress, can cause biomolecular condensates represented by stress granules (SGs) via liquid-liquid phase separation. We have previously shown that Hsp90 forms aggregates in response to HS and that Hsp90 aggregates transiently co-localize with SGs as visualized by Pabp. Here, we showed that arsenite, one of the well-described SG-inducing stimuli, induces Hsp90 aggregates distinct from conventional SGs in fission yeast. Arsenite induced Hsp90 granules in a dose-dependent manner, and these granules were significantly diminished by the co-treatment with a ROS scavenger N-acetyl cysteine (NAC), indicating that ROS are required for the formation of Hsp90 granules upon arsenite stress. Notably, Hsp90 granules induced by arsenite do not overlap with conventional SGs as represented by eIF4G or Pabp, while HS-induced Hsp90 granules co-localize with SGs. Nrd1, an RNA-binding protein known as a HS-induced SG component, was recruited into Hsp90 aggregates but not to the conventional SGs upon arsenite stress. The non-phosphorylatable eIF2α mutants significantly delayed the Hsp90 granule formation upon arsenite treatment. Importantly, inhibition of Hsp90 by geldanamycin impaired the Hsp90 granule formation and reduced the arsenite tolerance. Collectively, arsenite stimulates two types of distinct aggregates, namely conventional SGs and a novel type of aggregates containing Hsp90 and Nrd1, wherein Hsp90 plays a role as a center for aggregation, and stress-specific compartmentalization of biomolecular condensates.

Inhibition of Hsp90 K284 Acetylation Aalleviates Cardiac Injury After Ischemia-Reperfusion Injury.

Our objective was to determine the role of acetyl-Hsp90 and its relationship with the NF-κB p65 signaling pathway in CVDs. We investigated the effect of acetyl-Hsp90 on cardiac inflammation and apoptosis after ischemia-reperfusion injury (I/RI). The results showed that the induction of acetyl-Hsp90 occurred in the heart during I/R and in primary cardiomyocytes during oxygen-glucose deprivation/reoxygenation (OGD/R). Moreover, the nonacetylated mutant of Hsp90 (Hsp90-K284R), through the regulation of ATPase activities within its N-terminal domain (NTD), indirectly or directly increases its interaction with NF-κB p65. This led to a reduction in the activation of the NF-κB p65 pathway, thereby attenuating inflammation, apoptosis, and fibrosis, ultimately leading to an improvement in cardiac function. Furthermore, we demonstrated that recombinant human interleukin-37 (rIL-37) exerts a similar cardioprotective effect by reducing acetylation at K284 of Hsp90 after inhibiting the expression of KAT2A.

The Role of HSP90 Molecular Chaperones in Depression: Potential Mechanisms.

Major depressive disorder (MDD) is characterized by high rates of disability and death and has become a public health problem that threatens human life and health worldwide. HPA axis disorder and neuroinflammation are two common biological abnormalities in MDD patients. Hsp90 is an important molecular chaperone that is widely distributed in the organism. Hsp90 binds to the co-chaperone and goes through a molecular chaperone cycle to complete its regulation of the client protein. Numerous studies have demonstrated that Hsp90 regulates how the HPA axis reacts to stress and how GR, the HPA axis' responsive substrate, matures. In addition, Hsp90 exhibits pro-inflammatory effects that are closely related to neuroinflammation in MDD. Currently, Hsp90 inhibitors have made some progress in the treatment of a variety of human diseases, but they still need to be improved. Further insight into the role of Hsp90 in MDD provides new ideas for the development of new antidepressant drugs targeting Hsp90.

Genome-Wide Identification, Molecular Characterization, and Expression Analysis of the HSP70 and HSP90 Gene Families in Thamnaconus septentrionalis.

Heat shock proteins (HSPs) are a class of highly conserved proteins that play an important role in biological responses to various environmental stresses. The mariculture of Thamnaconus septentrionalis, a burgeoning aquaculture species in China, frequently encounters stressors such as extreme temperatures, salinity variations, and elevated ammonia levels. However, systematic identification and analysis of the HSP70 and HSP90 gene families in T. septentrionalis remain unexplored. This study conducted the first genome-wide identification of 12 HSP70 and 4 HSP90 genes in T. septentrionalis, followed by a comprehensive analysis including phylogenetics, gene structure, conserved domains, chromosomal localization, and expression profiling. Expression analysis from RNA-seq data across various tissues and developmental stages revealed predominant expression in muscle, spleen, and liver, with the highest expression found during the tailbud stage, followed by the gastrula, neurula, and juvenile stages. Under abiotic stress, most HSP70 and HSP90 genes were upregulated in response to high temperature, high salinity, and low salinity, notably hspa5 during thermal stress, hspa14 in high salinity, and hsp90ab1 under low salinity conditions. Ammonia stress led to a predominance of downregulated HSP genes in the liver, particularly hspa2, while upregulation was observed in the gills, especially for hsp90b1. Quantitative real-time PCR analysis corroborated the expression levels under environmental stresses, validating their involvement in stress responses. This investigation provides insights into the molecular mechanisms of HSP70 and HSP90 in T. septentrionalis under stress, offering valuable information for future functional studies of HSPs in teleost evolution, optimizing aquaculture techniques, and developing stress-resistant strains.

Hsp90 Promotes Gastric Cancer Cell Metastasis and Stemness by Regulating the Regional Distribution of Glycolysis-Related Metabolic Enzymes in the Cytoplasm.

Heat-shock protein 90 (Hsp90) plays a crucial role in tumorigenesis and tumor progression; however, its mechanism of action in gastric cancer (GC) remains unclear. Here, the role of Hsp90 in GC metabolism is the focus of this research. High expression of Hsp90 in GC tissues can interact with glycolysis, collectively affecting prognosis in clinical samples. Both in vitro and in vivo experiments demonstrate that Hsp90 is able to regulate the migration and stemness properties of GC cells. Metabolic phenotype analyses indicate that Hsp90 influences glycolytic metabolism. Mechanistically, Hsp90 interacts with glycolysis-related enzymes, forming multienzyme complexes to enhance glycolysis efficiency and yield. Additionally, Hsp90 binds to cytoskeleton-related proteins, regulating the regional distribution of glycolytic enzymes at the cell margin and lamellar pseudopods. This effect could lead to a local increase in efficient energy supply from glycolysis, further promoting epithelial-mesenchymal transition (EMT) and metastasis. In summary, Hsp90, through its interaction with metabolic enzymes related to glycolysis, forms multi-enzyme complexes and regulates regional distribution of glycolysis by dynamic cytoskeletal adjustments, thereby promoting the migration and stemness of GC cells. These conclusions also support the potential for a combined targeted approach involving Hsp90, glycolysis, and the cytoskeleton in clinical therapy.