HSP90 N-terminal inhibition promotes mitochondria-derived vesicles related metastasis by reducing TFEB transcription via decreased HSP90AA1-HCFC1 interaction in liver cancer.

Cancer cells compensate with increasing mitochondria-derived vesicles (MDVs) to maintain mitochondrial homeostasis, when canonical MAP1LC3B/LC3B (microtubule associated protein 1 light chain 3 beta)-mediated mitophagy is lacking. MDVs promote the transport of mitochondrial components into extracellular vesicles (EVs) and induce tumor metastasis. Although HSP90 (heat shock protein 90) chaperones hundreds of client proteins and its inhibitors suppress tumors, HSP90 inhibitors-related chemotherapy is associated with unexpected metastasis. Herein, we find that HSP90 inhibitor causes mitochondrial damage but stimulates the low LC3-induced MDVs and the release of MDVs-derived EVs. However, why LC3 decreases and what is the transcriptional regulatory mechanism of MDVs formation under HSP90 inhibition remain unknown. Because TFEB (transcription factor EB) is the most important mitophagy transcription factor, and the HSP90 client HCFC1 (host cell factor C1) regulates TFEB transcription, there should be a hidden connection between TFEB, HCFC1 and HSP90 in MDVs formation. Our results support the idea that HSP90 N-terminal inhibition reduces TFEB transcription via decreased HSP90AA1-HCFC1 interaction, which prevents HCFC1 from binding to the TFEB proximal promoter region. Decreased TFEB transcription and consequently reduced LC3, ultimately promoted MDVs formation. Blocking MDVs formation with the microtubule inhibitor nocodazole (NOC) activates the HCFC1-TFEB-LC3 axis, weakens HSP90 inhibitors-induced MDVs and the release of MDVs-derived EVs, inhibits the growth of tumor cell spheres and primary liver tumors, and reduces the extravasation of cancer cells to secondary metastatic sites. Taken together, these data suggest that combination therapy should be used to reduce the metastatic risk of low TFEB-triggered-MDVs formation caused by HSP90 inhibitors.

Endothelial Unfolded Protein Response-Mediated Cytoskeletal Effects.

The endothelial semipermeable monolayers ensure tissue homeostasis, are subjected to a plethora of stimuli, and their function depends on cytoskeletal integrity and remodeling. The permeability of those membranes can fluctuate to maintain organ homeostasis. In cases of severe injury, inflammation or disease, barrier hyperpermeability can cause irreparable damage of endothelium-dependent issues, and eventually death. Elucidation of the signaling regulating cytoskeletal structure and barrier integrity promotes the development of targeted pharmacotherapies towards disorders related to the impaired endothelium (e.g., acute respiratory distress syndrome, sepsis). Recent reports investigate the role of unfolded protein response in barrier function. Herein we review the cytoskeletal components, the unfolded protein response function; and their interrelations on health and disorder. Moreover, we emphasize on unfolded protein response modulators, since they ameliorate illness related to endothelial leak.

Pharmacological upregulation of macrophage-derived itaconic acid by pubescenoside C attenuated myocardial ischemia-reperfusion injury.

INTRODUCTION: Myocardial ischemia-reperfusion injury (MIRI) remains a prevalent clinical challenge globally, lacking an ideal therapeutic strategy. Macrophages play a pivotal role in MIRI pathophysiology, exhibiting dynamic inflammatory and resolutive functions. Macrophage polarization and metabolism are intricately linked to MIRI, presenting potential therapeutic targets. Pubescenoside C (PBC) from Ilex pubescens showed significantly anti-inflammatory effects, however, the effect of PBC on MIRI is unknown. OBJECTIVES: This study aimed to assess the cardioprotective effects of PBC against MIRI and elucidate the underlying mechanisms. METHODS: Sprague-Dawley rats, H9c2 and RAW264.7 macrophages were used to establish the in vitro and in vivo models of MIRI. TTC/Evans blue staining, immunohistochemical staining, metabonomics analysis, chemical probe, surface plasmon resonance (SPR), co-immunoprecipitation (CO-IP) assays were used for pharmacodynamic and mechanism study. RESULTS: PBC administration effectively reduced myocardial infarct size, decreased ST-segment elevation, and lowered CK-MB levels, concurrently promoting macrophage M2 polarization in MIRI. Furthermore, PBC-treated macrophages and their conditioned culture medium attenuated the apoptosis of H9c2 cells induced by oxygen-glucose deprivation/reoxygenation (OGD/R). Metabonomics analysis revealed that PBC increased the production of itaconic acid (ITA) and malic acid (MA) in macrophages, which conferred protection against OGD/R injury in H9c2 cells. Mechanistic investigations indicated that ITA exerted its effects by covalently modifying pyruvate kinase M2 (PKM2) at Cys474, Cys424, and Lys151, thereby facilitating PKM2's mitochondrial translocation and enhancing the PKM2/Bcl2 interaction, subsequently leading to decreased degradation of Bcl2. SPR assays further revealed that PBC bound to HSP90, facilitating the interaction between HSP90 and GSK3ß and resulting in the inactivation of GSK3ß activity and upregulation of key metabolic enzymes for ITA and MA production (Acod1 and Mdh2). CONCLUSION: PBC alleviates MIRI-induced cardiomyocyte apoptosis by modulating the HSP90/ITA/PKM2 axis. Furthermore, pharmacological upregulation of ITA emerges as a promising therapeutic approach for MIRI, hinting at PBC's potential as a candidate drug for MIRI therapy.

Polo-like kinase 2 promotes microglial activation via regulation of the HSP90α/IKKß pathway.

Polo-like kinase 2 (PLK2) is a serine/threonine protein kinase associated with the regulation of synaptic plasticity and centriole duplication. We identify PLK2 as a crucial early-response gene in lipopolysaccharide (LPS)-stimulated microglial cells. Knockdown or inhibition of PLK2 remarkably attenuates LPS-induced expression of proinflammatory factors in microglial cells by suppressing the inhibitor of nuclear factor kappa B kinase subunit beta (IKKß)-nuclear factor (NF)-κB signaling pathway. We identify heat shock protein 90 alpha (HSP90α), a regulator of IKKß activity, as a novel PLK2 substrate. Knockdown or pharmacological inhibition of HSP90α abolishes PLK2-mediated activation of NF-κB transcriptional activity and microglial inflammatory activation. Furthermore, phosphoproteomic analysis pinpoints Ser252 and Ser263 on HSP90α as novel phosphorylation targets of PLK2. Lastly, conditional knockout of PLK2 in microglial cells dramatically ameliorates neuroinflammation and subsequent dopaminergic neuron loss in an intracranial LPS-induced mouse Parkinson's disease (PD) model. The present study reveals that PLK2 promotes microglial activation through the phosphorylation of HSP90α and subsequent activation of the IKKß-NF-κB signaling pathway.

Schwann cell-secreted frizzled-related protein 1 dictates neuroinflammation and peripheral nerve degeneration after neurotrauma.

Neurotrauma in limbs can induce sustained neuroinflammation, resulting in persistent disruption of nerve tissue architecture and retardation of axon regrowth. Despite macrophage-mediated inflammation promoting the removal of necrotic neural components and stimulating neo-vessel ingrowth, detrimental shifts in macrophage phenotype exacerbate nerve degeneration. Herein, we find that peripheral nerve injuries (PNIs) result in abundant secreted frizzled-related protein 1 (sFRP1) expression, particularly by Schwann cells (SCs). Heat shock protein 90 (HSP90) in macrophages recognizes sFRP1 and triggers a dysregulated secretion of inflammatory mediators. Single-cell atlas of human injured peripheral nerves reveals the appearance of sFRP1-expressing SCs with mesenchymal traits and macrophages with a proinflammatory genetic profile. Deletion of either SC-specific sFRP1 or macrophage-specific HSP90 alleviates neuroinflammation and prevents the progression of nerve degeneration. Together, our findings implicate the response of macrophages to SC-derived sFRP1 in exacerbating nerve damage following PNIs.

GbHSP90 act as a dual functional role regulated in telomere stability in Ginkgo biloba.

The heat shock protein 90 (HSP90) family members are not only widely involved in animal cellular immune response and signal transduction pathway regulation, but also play an important role in plant development and environmental stress response. Here,we identified a HSP90 family member in Ginkgo biloba, designated as GbHSP90, which performs a dual functional role to regulate telomere stability. GbHSP90 was screened by a yeast one-hybrid library using the Ginkgo biloba telomeric DNA (TTTAGGG)5. Fluorescence polarization, surface plasmon resonance(SPR) and EMSA technologyies revealed a specific interaction between GbHSP90 and the double-stranded telomeric DNA via its N-CR region, with no affinity for the single-stranded telomeric DNA or human double-stranded telomeric DNA. Furthermore, yeast two-hybrid system and Split-LUC assay demonstrated that GbHSP90 can interacts with two telomere end-binding proteins:the ginkgo telomerase reverse transcriptase (GbTERT) and the ginkgo Structural Maintenance of Chromosomes protein 1 (GbSMC1). Overexpression of GbHSP90 in human 293 T and HeLa cells increased cell growth rate, the content of telomerase reverse transcriptase (TERT), and promote cell division and inhibit cell apoptosis. Our results indicated GbHSP90 have dually functions: as a telomere-binding protein that binds specifically to double-stranded telomeric DNA and as a molecular chaperone that modulates cell differentiation and apoptosis by binding to telomere protein complexes in Ginkgo biloba. This study contributes to a significantly understanding of the unique telomere complex structure and regulatory mechanisms in Ginkgo biloba, a long-lived tree species.

Development and Preclinical Evaluation of 18F-Labeled PEGylated Sansalvamide A Decapeptide for Noninvasive Evaluation of Hsp90 Status in Pancreas Cancer.

Heat shock protein 90 (Hsp90) is a promising target for cancer therapy and imaging. Accurate detection of Hsp90 levels in tumors via noninvasive PET imaging might be beneficial for management. To achieve this, the precursor compound Dimer-Sansalvamide A (Dimer-San A) was PEGylated and modified by conjugating it with the bifunctional chelator 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). The 18F-labeled PEGylated Dimer-SanA decapeptide (18F-PEGylated San A) was completed within 30 min using a two-step process. In vitro stability and specificity were assessed, including competition studies with the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG). MicroPET imaging was performed on PL45 tumor-bearing mice to evaluate probe accumulation and tumor-to-muscle ratios. Biodistribution studies determined the route of excretion. The probe resulted in a radiochemical yield of 23.11% with a purity exceeding 95%. In vitro, 18F-PEGylated San A exhibited high stability and selectively accumulated in Hsp90-positive PL45 cells, with binding effectively blocked by the Hsp90 inhibitor 17AAG, confirming its specificity. MicroPET imaging of PL45 tumor-bearing mice showed significant probe accumulation in tumor tissues at 1 and 2 h postinjection (4.06 ± 0.30 and 3.72 ± 0.61%ID/g, respectively), with optimal tumor-to-muscle ratios observed at 2 h postinjection (6.09 ± 1.92). While 18F-PEGylated San A demonstrates enhanced water solubility, as indicated by increased kidney uptake relative to liver accumulation. The study successfully incorporated PEG units to create the novel probe 18F-PEGylated San A targeting to Hsp90 without affecting its targeting capability, aimed at improving the pharmacokinetics and PET imaging of Hsp90 expression noninvasively.

EP4 receptor agonist CAY10598 upregulates ROS-dependent Hsp90 cleavage in colorectal cancer cells.

Prostaglandin E2 (PGE2) interacts with four specific G protein-coupled receptors, namely EP1, EP2, EP3, and EP4, playing a pivotal role in determining the fate of cells. Our previous findings highlighted that stimulating the EP4 receptor with its agonist, CAY10598, triggers apoptosis in colon cancer HCT116 cells via the production of reactive oxygen species (ROS). This process also reduces the phosphorylation of the oncogenic protein JAK2 and leads to its degradation in these cells. In this study, our goal was to explore the pathways through which CAY10598 leads to JAK2 degradation. We focused on Hsp90, a heat shock protein family member known for its role as a molecular chaperone maintaining the stability of several key proteins including EGFR, MET, Akt, and JAK2. Our results show that CAY10598 decreases the levels of client proteins of Hsp90 in HCT116 cells, an effect reversible by pretreatment with the ROS scavenger N-acetyl cysteine (NAC) or the proteasome inhibitor MG132, indicating that the degradation is likely driven by ROS. Furthermore, we observed that CAY10598 cleaves both α and ß isoforms of Hsp90, the process inhibited by NAC. Inhibition of EP4 with the antagonist GW627368x not only prevented the degradation of Hsp90 client proteins but also the cleavage of Hsp90 itself in CAY10598-treated HCT116 cells. Additionally, CAY10598 suppressed the growth of HCT116 cells implanted in mice. Our findings reveal that CAY10598 induces apoptosis in cancer cells by a novel mechanism involving the ROS-dependent cleavage of Hsp90, thereby inhibiting the function of crucial Hsp90 client proteins.

Safe concentration, unsafe effects: Impact of BPA on antioxidant function in the hepatopancreas and ovarian gene expression in oriental river prawns (Macrobrachium nipponense).

This study investigated the effects of Bisphenol A (BPA), a common endocrine-disrupting chemical, on the antioxidant enzyme activities in the hepatopancreas and the expression of genes related to ovarian development in oriental river prawns (Macrobrachium nipponense). The 24hLC50 and 48hLC50 values for BPA were 80.59 mg/L and 63.90 mg/L, respectively, with a safe concentration of 12.06 mg/L. Prawns were exposed to low (4.85 mg/L), safe (12.06 mg/L), and high (30.00 mg/L) concentrations of BPA for 10 days to measure enzyme activities, and for 20 days followed by 7 days in BPA-free water to measure gene expression. Short-term exposure (12 h, 1d, 3d) to low concentration BPA did not significantly affect superoxide dismutase (SOD) activity in the hepatopancreas (P > 0.05), but long-term exposure (6d, 10d) significantly reduced SOD activity (P < 0.05). Catalase (CAT) activity showed no significant changes throughout the low concentration exposure period (P > 0.05). At safe and high concentrations, SOD and CAT activities significantly decreased after 12 h of exposure (P < 0.05). BPA affected heat shock protein 90 (HSP90) expression in the ovary, with low concentration BPA significantly upregulating HSP90 after 1 day (P < 0.05), but returning to normal levels after 10 and 20 days. At the safe concentration, HSP90 was significantly upregulated at all three sampling points (1d, 10d, 20d) (P < 0.05), while high concentration exposure led to significant upregulation only on day 10 (P < 0.05). Low concentration BPA had no significant effect on Cathepsin B (CB) and Cathepsin L (CL) gene expression in the ovaries (P > 0.05). However, safe concentration exposure promoted CB expression on days 1, 10, and 20 (P < 0.05), while high concentration exposure significantly increased CB expression on day 1 (P < 0.05), with levels returning to normal on days 10 and 20. CL expression significantly increased after 20 days of exposure to both safe and high concentrations (P < 0.05). Gene expression levels in the ovaries returned to normal after transfer to BPA-free water, with HSP90 and CB normalizing by day 1, and CL by day 7. These results indicate that even safe concentrations of BPA impose stress on the hepatopancreas and increase the expression of HSP90, CB, and CL genes in the ovaries, affecting ovarian development. And, these effects are reversible within a certain period after the removal of BPA.

Antiproliferative Impact of Linagliptin on the Cervical Cancer Cell Line.

OBJECTIVE: This study aimed to assess linagliptin's inhibitory effects on the proliferation of cervical cancer cell lines and investigate its potential for targeting human heat shock protein 90. METHODS: Linagliptin's cytotoxicity was assessed on a cervical cancer cell line (Hela cancer cell line) at two different incubation periods, 24 and 72 hours. The molecular docking between linagliptin and the receptor protein human Hsp 90 (PDB code: 5XRE) was performed using the Biovia Discovery Studio and AutoDock tool software. The Discovery Studio visualizer generated three-dimensional (3D) and two-dimensional (2D) interactive images. RESULTS: The study's cytotoxicity results demonstrated that linagliptin can inhibit the proliferation of cervical cancer cells. The cytotoxicity exhibited a time-dependent pattern (cell cycle specific). The molecular docking study was conducted to investigate the interaction between linagliptin and human Hsp90. The study identified 11 sites where linagliptin can bind to Hsp90 amino acid residues. The total docking score for this interaction was -10.3 kcal/mol. The most potent binding occurred through conventional hydrogen bonds with the ASP:54 amino acid residues at a distance of 2.93 Å. The docking scores for linagliptin were comparable to those of the reference drug geldanamycin, indicating a strong interaction between linagliptin and Hsp90. CONCLUSION: The study has found that linagliptin successfully reduces the growth of cervical cancer cells with a time-dependent cytotoxic pattern. The potential anticancer mechanism of linagliptin can be inferred by analyzing the docking score and docking pattern between linagliptin and Hsp90, suggesting that linagliptin targets human Hsp 90.

Enzymatic Hydrolysis of Resorcylic Acid Lactones by an Aeromicrobium sp.

Zearalenone and radicicol are resorcylic acid lactones produced by numerous plant pathogenic fungi. Zearalenone is a non-steroidal estrogen mimic that can cause serious reproductive issues in livestock that consume contaminated feed. Radicicol is a potent inhibitor of the molecular chaperone Hsp90, which, in plants, has an important role in coordinating the host's immune response during infection. Here, we describe the identification and characterization of a soil-borne strain of the Gram-positive bacterium Aeromicrobium sp. capable of hydrolyzing the macrolide ring of resorcylic acid lactones, including zearalenone and radicicol. Proteomic analysis of biochemically enriched fractions from the isolated and cultured bacterium identified an α/ß-hydrolase responsible for this activity. A recombinantly expressed and purified form of the hydrolase (termed RALH) was active against both zearalenone and radicicol. Interpretation of high-resolution mass spectrometry and NMR data confirmed the structures of the enzymatic products as the previously reported non-toxic metabolite hydrolyzed zearalenone and hydrolyzed radicicol. Hydrolyzed radicicol was demonstrated to no longer inhibit the ATPase activity of the Saccharomyces cerevisiae Hsp90 homolog in vitro. Enzymatic degradation of resorcylic acid lactones will enable insight into their biological functions.

SUMOylation of protein phosphatase 5 regulates phosphatase activity and substrate release.

The serine/threonine protein phosphatase 5 (PP5) regulates hormone and stress-induced signaling networks. Unlike other phosphoprotein phosphatases, PP5 contains both regulatory and catalytic domains and is further regulated through post-translational modifications (PTMs). Here we identify that SUMOylation of K430 in the catalytic domain of PP5 regulates phosphatase activity. Additionally, phosphorylation of PP5-T362 is pre-requisite for SUMOylation, suggesting the ordered addition of PTMs regulates PP5 function in cells. Using the glucocorticoid receptor, a well known substrate for PP5, we demonstrate that SUMOylation results in substrate release from PP5. We harness this information to create a non-SUMOylatable K430R mutant as a 'substrate trap' and globally identified novel PP5 substrate candidates. Lastly, we generated a consensus dephosphorylation motif using known substrates, and verified its presence in the new candidate substrates. This study unravels the impact of cross talk of SUMOylation and phosphorylation on PP5 phosphatase activity and substrate release in cells.

The Investigation of Hsp90C-Terminal Inhibitors Containing Amide Bioisosteres.

Heat Shock Protein 90 (Hsp90) is responsible for the proper folding and maturation of ~400 client protein substrates, many of which are directly associated with the ten hallmarks of cancer. Hsp90 is a great target for cancer therapy including melanoma, since Hsp90 inhibition can disrupt multiple oncogenic pathways simultaneously. In this study, we report the synthesis and anti-proliferative activity manifested by a series of Hsp90 C-terminal inhibitors against mutant BRAF and wild-type BRAF melanoma cells. Furthermore, we explored structure-activity relationships (SAR) for the amide moiety of 6 (B1), a novel Hsp90C-terminal inhibitor via introduction of amide bioisosteres. Compound 6 displayed an IC50 of 1.01 µM, 0.782 µM, 0.607 µM and 1.413 µM against SKMel173, SKMel103, SKMel19 and A375 cells, respectively.

The expression of miR-21, HSP90a and gGASP-1 in serum of patients with lung cancer and their correlation with pathological subtypes.

Background: To investigate the expression of miR-21, heat shock protein-90a (HSP90a) and G protein-coupled receptorrelated sorting protein 1(GASP-1) in the serum of lung cancer patients and their correlation with pathological subtypes. Methods: Eighty patients with lung cancer were included in the lung cancer group from May 2020 to May 2022, and 40 volunteers who underwent physical examination were randomly included in the control group according to the group ratio of 2:1. This ratio balances the need for a sufficiently large experimental group to detect significant effects with the practicality of recruiting a manageable control group. To ensure the validity of our findings, we meticulously calculated the sample size to achieve adequate statistical power, thus enabling us to draw reliable conclusions. Serum miR-21, HSP90a and GASP-1 levels of patients in the two groups were detected. We quantitatively assessed the serum levels of miR-21, HSP90a, and GASP1 in lung cancer patients and healthy volunteers. We employed enzyme-linked immunosorbent assay (ELISA) for HSP90a and GASP-1, and reverse transcription-polymerase chain reaction (RT-PCR) for miR-21, ensuring precise quantification. To explore the correlation between it and pathological subtypes, TNM stage and lymph node metastasis of lung cancer patients. TNM stands for Tumor, Node, and Metastasis. This system is widely used for staging cancer and describes the size and extent of the primary tumor (T), the absence or presence of cancer in nearby lymph nodes (N), and whether the cancer has spread to other parts of the body (M). Results: The serum levels of miR-21, HSP90a and GASP1 in lung cancer group were higher than those in control group (P < 0.05). ROC curve analysis showed that serum miR-21, HSP90a and GASP-1 levels had certain value in the diagnosis of lung cancer, and their AUC values were 0.901, 0.874 and 0.865, respectively (P < 0.05). There was no difference in the relative expression level of serum miR-21 between squamous cell carcinoma group and adenocarcinoma group (P>0.05), but the levels of HSP90a and GASP-1 in adenocarcinoma group were higher than those in squamous cell carcinoma group (P < 0.05). There was no difference in the levels of serum miR-21, HSP90a and GASP-1 between stage I and stage II groups (P>0.05). The levels of serum miR-21, HSP90a and GASP-1 in stage III and stage IV groups were higher than those in stage I and stage II groups, and those in stage IV were higher than those in stage III group (P < 0.05). The serum levels of miR-21, HSP90a and GASP-1 in patients with metastasis were higher than those in patients without metastasis (P < 0.05). Conclusions: Our study concludes that there is a notable association between elevated serum levels of miR-21, HSP90a, and GASP-1 and lung cancer. However, it is crucial to acknowledge that these findings are preliminary and further statistical analysis is needed to strengthen these associations. Future studies with comprehensive statistical evaluation will be vital to validate these potential biomarkers for lung cancer diagnosis and prognosis.

Extracellular heat shock protein 90 alpha (eHsp90α)'s role in cancer progression and the development of therapeutic strategies.

Heat shock protein 90 alpha (Hsp90α) is an abundantly expressed and evolutionarily conserved molecular chaperone. Hsp90α is the inducible Hsp90 isoform, and its expression and secretion extracellularly (eHsp90α) can be triggered in response to a variety of cellular stresses to protect/activate client proteins and to facilitate cellular adjustment to the stress. As a result, cancers often have high expression levels of intracellular and extracellular (plasma) Hsp90α, allowing them to support their oncogenesis and progression. In fact, (e)Hsp90α has been implicated in regulating processes such as cell signaling transduction, DNA repair, promotion of the Epithelial-to-Mesenchymal Transition (EMT), promotion of angiogenesis, immune response, and cell migration. Hsp90α levels have been correlated with cancer progression and severity in several cancers, indicating that it may be a useful biomarker or drug-target for cancer. To date, the development of intracellular Hsp90α-targeted therapies include standard N-terminal ATP-competitive inhibitors and allosteric regulators that bind to Hsp90α's middle or C-terminal domain. On-target toxicities and dosing complications as a result of Hsp90α inhibition has driven the development of eHsp90α-targeted therapies. Examples include anti-Hsp90α monoclonal antibodies and cell-impermeable Hsp90α small molecule inhibitors. This review aims to discuss the many roles Hsp90α plays in cancer progression with a focus on the current development of Hsp90α-targeted therapies.

Possible mechanisms underlying the regulation of postmenopausal osteoporosis by follicle-stimulating hormone.

Objective: To explore the possible mechanisms by which follicle-stimulating hormone (FSH) regulates postmenopausal osteoporosis through the FSH/FSH receptor (FSHr)/G protein/C/EBPß/heat shock protein 90 alpha (HSP90α) signalling pathways. Methods: We measured serum FSH, luteinising hormone (LH), and HSP90α levels in the serum and adipose tissue of women of childbearing age and menopausal status. In the in vivo studies, 12 B57CL female mice were divided equally into Sham, OVX, and OVX + FSHr Blocker groups. Serum levels of alkaline phosphatase, FSH, and HSP90α, along with StRACP vitality, were determined, and femur micro-computed tomography was performed. Additionally, FSH, FSHr, G protein, C/EBPß, and HSP90α levels were assessed using quantitative polymerase chain reaction. Finally, we divided the human multiple myeloma cell line U266 into three groups. The activity of tartrate-resistant acid phosphatase (TRAP) in the supernatant at different stages was detected, and myeloma cells were stained with TRAP. Results: HSP90α levels in adipose tissue supernatant and serum were lower in women of childbearing age than in menopausal women (P < 0.05). Serum FSH and HSP90α levels demonstrated a strong correlation. Treatment with FSHr blockers resulted in decreased FSH, FSHr, G protein, C/EBPß, and HSP90α levels in mice. TRAP staining of osteoclast-like cells exhibited a significantly higher intensity in the M-CSF + RANKL + recombinant HSP90α group than in the M-CSF + RANKL and blank control groups (P < 0.05). Conclusions: Our results indicate that FSH promotes HSP90α secretion by adipocytes via the FSHr/G protein/C/EBPß pathway. This mechanism affects osteoclast activity and exacerbates osteoporosis.

Hsp90α promotes chemoresistance in pancreatic cancer by regulating Keap1-Nrf2 axis and inhibiting ferroptosis.

Chemoresistance is the primary reason for poor prognosis in patients with pancreatic cancer (PC). Recent studies have indicated that ferroptosis may improve chemoresistance, but the underlying mechanisms remain unclear. In this study, significant upregulation of heat shock protein 90α (Hsp90α) expression is detected in the peripheral blood and tissue samples of patients with chemoresistant PC. Further studies reveal that Hsp90α promotes the proliferation, migration, and invasion of a chemoresistant pancreatic cell line (Panc-1-gem) by suppressing ferroptosis. Hsp90α competitively binds to Kelch-like ECH-associated protein 1 (Keap1), liberating nuclear factor erythroid 2-related factor 2 (Nrf2) from Keap1 sequestration. Nrf2 subsequently translocates into the nucleus and activates the glutathione peroxidase 4 (GPX4) pathway, thereby suppressing ferroptosis. This process further worsens the chemoresistance of PC cells. This study provides valuable insight into potential molecular targets to overcome chemoresistance in PC. It sheds light on the intricate mechanisms linking Hsp90α and ferroptosis to chemoresistance in PC and provides a theoretical foundation for the development of novel therapeutic strategies.

ClassIIb histone deacetylase participates in perioperative neurocognitive disorders in elderly mice via HSP90/GR signaling pathway.

OBJECTIVE: Multiple factors contribute to the development of perioperative neurocognitive disorders (PND). This study was designed to investigate whether Histone Deacetylase 6 (HDAC6) was involved in the formation of postoperative cognitive dysfunction in elderly mice by regulating the degree of acetylation of heat shock protein (HSP90) and related protein functions and quantities. METHODS: C57BL/6 J male mice were randomly divided into six groups: control naive (group Control), anesthesia (group Anesthesia), splenectomy surgery (group Surgery), splenectomy surgery plus dissolvent (group Vehicles), splenectomy surgery plus the inhibitor ACY-1215 (group Ricolinostat), and splenectomy surgery plus the inhibitor RU-486(group Mifepristone). After the mice were trained for Morris Water Maze (MWM) test for five days, anesthesia and operational surgery were carried out the following day. Cognitive function was assessed on the 1st, 3rd and 7th days post-surgery. The hippocampi were harvested on days 1, 3, and 7 post-surgeries for Western blots and ELISA assays. RESULTS: Mice with the splenectomy surgery displayed the activation of the hypothalamic-pituitary-adrenal axis (HPA-axis), marked an increase in adrenocorticotropic hormone (ACTH), glucocorticoid, mineralocorticoid at the molecular level and impaired spatial memory in the MWM test. The hippocampus of surgical groups showed a decrease in acetylated HSP90, a rise in glucocorticoid receptor (GR)-HSP90 association, and an increase in GR phosphorylation and translocation. HDAC6 was increased after the surgical treated. Using two specific inhibitors, HDAC6 inhibitor Ricolinostat (ACY-1215) and GR inhibitor Mifepristone (RU-486), can partially mitigate the effects caused by surgical operation. CONCLUSIONS: Abdominal surgery may impair hippocampal spatial memory, possibly through the HDAC6-triggered increase in the function of HSP90, consequently strengthening the negative role of steroids in cognitive function. Targeting HDAC6- HSP90/GR signaling may provide a potential avenue for the treatment of the impairment of cognitive function after surgery.

Role of HSP90 in Type 2 Diabetes Mellitus and Its Association with Liver Diseases.

Non-alcoholic fatty acid liver disease (NAFLD), non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) are the fatal liver diseases which encompass a spectrum of disease severity associated with increased risk of type 2 diabetes mellitus (T2DM), a metabolic disorder. Heat shock proteins serve as markers in early prognosis and diagnosis of early stages of liver diseases associated with metabolic disorder. This review aims to comprehensively investigate the significance of HSP90 isoforms in T2DM and liver diseases. Additionally, we explore the collective knowledge on plant-based drug compounds that regulate HSP90 isoform targets, highlighting their potential in treating T2DM-associated liver diseases. Furthermore, this review focuses on the computational systems' biology and next-generation sequencing technology approaches that are used to unravel the potential medicine for the treatment of pleiotropy of these 2 diseases and to further elucidate the mechanism.

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.