Inhibition Of Heat Shock Protein Research Articles

Inhibiting AGS Cancer Cell Proliferation through the Combined Application of Aucklandiae Radix and Hyperthermia: Investigating the Roles of Heat Shock Proteins and Reactive Oxygen Species

Cancer is a major global health concern. To address this, the combination of traditional medicine and newly appreciated therapeutic modalities has been gaining considerable attention. This study explores the combined effects of Aucklandiae Radix (AR) and 43 °C hyperthermia (HT) on human gastric adenocarcinoma (AGS) cell proliferation and apoptosis. We investigated the synergistic effects of AR and HT on cell viability, apoptosis, cell cycle progression, and reactive oxygen species (ROS)-dependent mechanisms. Our findings suggest that the combined treatment led to a notable decrease in AGS cell viability and increased apoptosis. Furthermore, cell cycle arrest at the G2/M phase contributed to the inhibition of cancer cell proliferation. Notably, the roles of heat shock proteins (HSPs) were highlighted, particularly in the context of ROS regulation and the induction of apoptosis. Overexpression of HSPs was observed in cells subjected to HT, whereas their levels were markedly reduced following AR treatment. The suppression of HSPs and the subsequent increase in ROS levels appeared to contribute to the activation of apoptosis, suggesting a potential role for HSPs in the combined therapy’s anti-cancer mechanisms. These findings provide valuable insights into the potential of integrating AR and HT in cancer and HSPs.

Cancer Cell-Mimicking Prussian Blue Nanoplatform for Synergistic Mild Photothermal/Chemotherapy via Heat Shock Protein Inhibition.

Combined mild-temperature photothermal/chemotherapy has emerged as a highly promising modality for tumor therapy. However, its therapeutic efficacy is drastically compromised by the heat-induced overexpression of heat shock proteins (HSPs) by the cells, which resist heat stress and apoptosis. The purpose of this study was to downregulate HSPs and enhance the mild-temperature photothermal/chemotherapy effect. In detail, the colon cancer cell membrane (CT26M)-camouflaged HSP90 inhibitor ganetespib and the chemotherapeutic agent doxorubicin (DOX)-coloaded hollow mesoporous Prussian blue (HMPB) nanoplatform (named PGDM) were designed for synergistic mild photothermal/chemotherapy via HSP inhibition. In addition to being a photothermal agent with a high efficiency of photothermal conversion (24.13%), HMPB offers a hollow hole that can be filled with drugs. Concurrently, the cancer cell membrane camouflaging enhances tumor accumulation through a homologous targeting mechanism and gives the nanoplatform the potential to evade the immune system. When exposed to NIR radiation, HMPB's photothermal action (44 °C) not only causes tumor cells to undergo apoptosis but also causes ganetespib to be released on demand. This inhibits the formation of HSP90, which enhances the mild photothermal/chemotherapy effect. The results confirmed that the combined treatment regimen of mild photothermal therapy (PTT) and chemotherapy showed a better therapeutic efficacy than the individual treatment methods. Therefore, this multimodal nanoparticle can advance the development of drugs for the treatment of malignancies, such as colon cancer, and has prospects for clinical application.

Discovery of Disubstituted Carboranes as Inhibitors of Heat Shock Protein 90–Heat Shock Factor 1 Interaction

Discovery of Disubstituted Carboranes as Inhibitors of Heat Shock Protein 90–Heat Shock Factor 1 Interaction

Ti2C3 MXene-based nanocomposite as an intelligent nanoplatform for efficient mild hyperthermia treatment

Photothermal therapy (PTT) has attracted much attention due to its less invasive, controllable and highly effective nature. However, PTT also suffers from intrinsic cancer resistance mediated by cell survival pathways. These survival pathways are regulated by a variety of proteins, among which heat shock protein (HSP) triggers thermotolerance and protects tumor cells from hyperthermia-induced apoptosis. Confronted by this challenge, we propose and validate here a novel MXene-based HSP-inhibited mild photothermal platform, which significantly enhances the sensitivity of tumor cells to heat-induced stress and thus improves the PPT efficacy. The Ti3C2@Qu nanocomposites are constructed by utilizing the high photothermal conversion ability of Ti3C2 nanosheets in combination with quercetin (Qu) as an inhibitor of HSP70. Qu molecules are loaded onto the nanoplatform in a pH-sensitive controlled release manner. The acidic environment of the tumor causes the burst-release of Qu molecules, which deplete the level of heat shock protein 70 (HSP70) in tumor cells and leave the tumor cells out from the protection of the heat-resistant survival pathway in advance, thus sensitizing the hyperthermia efficacy. The nanostructure, photothermal properties, pH-responsive controlled release, synergistic photothermal ablation of tumor cells in vitro and in vivo, and hyperthermia effect on subcellular structures of the Ti3C2@Qu nanocomposites were systematically investigated.

Abstract 3353: The emerging role of extracellular HSP90 in prostate cancer progression to a metastatic phenotype

Abstract Background: Metastasis is the central cause of lethal prostate cancer (PCa). Mechanisms regulating metastasis represent high-potential therapeutic targets for preventing development of lethal PCa. Inhibitors of extracellular heat shock protein 90 (eHSP90) have been shown to inhibit prostate cell motility. In contrast to the intracellular HSP90 (iHSP90), whose biology has been extensively studied, and whose therapeutic targeting is associated with systemic toxicity, the biology of extracellular HSP90 is not well understood. We undertook a series of investigations to better understand eHSP90 biology in PCa. Methods: Human PCa cells were subjected to cellular stress by heat shock combined with serum starvation. Resultant conditioned media was probed for matrix metalloproteinase 2 (MMP-2) by zymography and subject to scratch-wound and Boyden chamber invasion assays. Expression of HSP90 and CDC37 was measured by Western blot. Plasma from patients with PCa and healthy controls was probed for eHSP90 by ELISA. Results: We have examined expression of iHSP90 and eHSP90 after cellular stress, induced by heat shock and serum starvation, in human PC3, LNCaP, C4-2B, 1532NPTX and 1532CPTX PCa cell lines. Cell stress induces increased eHSP90 in all PCa cell lines examined. This is associated with a decrease in MMP-2 activity in conditioned media. Conditioned media from stressed cells was also shown to decrease invasion of PC3 cells, consistent with changes in MMP-2. Of high interest, the addition of protease inhibitors to conditioned media led to a complete reversal of the MMP-2 response: its activity increased with cellular stress. When measuring HSP90α in plasma from healthy controls (N = 20) and patients with PCa (N = 40, 20 localized and 20 metastatic), we demonstrated a significant (p=.001) >2 fold increase in PCa compared to control. Further, a significant increase in HSP90α was observed when low versus high T stage lesions were compared. There was no statistically significant difference in HSP90α for those with metastasis to regional lymph nodes, non-regional lymph nodes, bone, or liver. Conclusion: We demonstrate that increased eHSP90 due to cellular stress is a response observed across all PCa cell lines examined and should be considered typical. Its association with extracellular MMP-2 activity is dependent on the presence of other proteases and indicates a complex regulatory mechanism. Examination of eHSP90 in humans supports its association with aggressive disease. These factors support further investigation of underlying biology and therapeutic opportunities. Citation Format: Katelyn O'Neill, Johnny Zigmond, Raymond Bergan. The emerging role of extracellular HSP90 in prostate cancer progression to a metastatic phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3353.

Light-activated NIR-II imaging-guided tumor therapy with enhanced HPTT/starvation cycle

Establishing a phototheranostic platform constructed by the second near-infrared (NIR-II) region has proved a revolutionary and promising strategy for cancer treatment. However, the antitumor effectiveness is severely limited by the monotonicity of the NIR-photothermal therapy (HPTT) modality and tumor thermotolerance caused by the production of heat shock proteins (HSPs). Here, a minimalistic approach is used to construct an organic nanoplatform (IFT@PEG-GOX NPs) with the reciprocal cyclic promotion of hypothermia and starvation treatments for NIR-II imaging-guided tumor therapy. After the enhanced permeability and retention (EPR) effect causes IFT@PEG-GOX NPs to accumulate in tumors, glucose oxidase (GOx)-mediated tumor starvation may obstruct the production of adenosine triphosphate (ATP) and downregulation heat shock proteins (HSPs), thereby reducing the thermotolerance of cells. After that, sensitized HPTT was activated and GOx's catalytic activity was increased by NIR laser irradiation. Then, there would be a subsequent, intensified inhibition of HSP along with an additional amplification of the GOx-mediated tumor starvation. As a consequence, the HPTT/Starvation therapy (ST) bidirectional cycle method is initiated, leading to a bidirectional cyclic enhancing impact of HPTT and ST and significantly better tumor suppression.

Enhancing Photothermal/Photodynamic Therapy for Glioblastoma by Tumor Hypoxia Alleviation and Heat Shock Protein Inhibition Using IR820-Conjugated Reduced Graphene Oxide Quantum Dots.

We use low-molecular-weight branched polyethylenimine (PEI) to produce cytocompatible reduced graphene oxide quantum dots (rGOQD) as a photothermal agent and covalently bind it with the photosensitizer IR-820. The rGOQD/IR820 shows high photothermal conversion efficiency and produces reactive oxygen species (ROS) after irradiation with near-infrared (NIR) light for photothermal/photodynamic therapy (PTT/PDT). To improve suspension stability, rGOQD/IR820 was PEGylated by anchoring with the DSPE hydrophobic tails in DSPE-PEG-Mal, leaving the maleimide (Mal) end group for covalent binding with manganese dioxide/bovine serum albumin (MnO2/BSA) and targeting ligand cell-penetrating peptide (CPP) to synthesize rGOQD/IR820/MnO2/CPP. As MnO2 can react with intracellular hydrogen peroxide to produce oxygen for alleviating the hypoxia condition in the acidic tumor microenvironment, the efficacy of PDT could be enhanced by generating more cytotoxic ROS with NIR light. Furthermore, quercetin (Q) was loaded to rGOQD through π-π interaction, which can be released in the endosomes and act as an inhibitor of heat shock protein 70 (HSP70). This sensitizes tumor cells to thermal stress and increases the efficacy of mild-temperature PTT with NIR irradiation. By simultaneously incorporating the HSP70 inhibitor (Q) and the in situ hypoxia alleviating agent (MnO2), the rGOQD/IR820/MnO2/Q/CPP can overcome the limitation of PTT/PDT and enhance the efficacy of targeted phototherapy in vitro. From in vivo study with an orthotopic brain tumor model, rGOQD/IR820/MnO2/Q/CPP administered through tail vein injection can cross the blood-brain barrier and accumulate in the intracranial tumor, after which NIR laser light irradiation can shrink the tumor and prolong the survival times of animals by simultaneously enhancing the efficacy of PTT/PDT to treat glioblastoma.

Astragalus membranaceus Extract Induces Apoptosis via Generation of Reactive Oxygen Species and Inhibition of Heat Shock Protein 27 and Androgen Receptor in Prostate Cancers.

Although Astragalus membranaceus is known to have anti-inflammatory, anti-obesity, and anti-oxidant properties, the underlying apoptotic mechanism of Astragalus membranaceus extract has never been elucidated in prostate cancer. In this paper, the apoptotic mechanism of a water extract from the dried root of Astragalus membranaceus (WAM) was investigated in prostate cancer cells in association with heat shock protein 27 (HSP27)/androgen receptor (AR) signaling. WAM increased cytotoxicity and the sub-G1 population, cleaved poly (ADP-ribose) polymerase (PARP) and cysteine aspartyl-specific protease 3 (caspase 3), and attenuated the expression of B-cell lymphoma 2 (Bcl-2) in LNCaP cells after 24 h of exposure. Consistently, WAM significantly increased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive LNCaP cells. WAM decreased the phosphorylation of HSP27 on Ser82 and inhibited the expression of the AR and prostate-specific antigen (PSA), along with reducing the nuclear translocation of p-HSP27 and the AR via the disturbed binding of p-HSP27 with the AR in LNCaP cells. WAM consistently inhibited the expression of the AR and PSA in dihydrotestosterone (DHT)-treated LNCaP cells. WAM also suppressed AR stability, both in the presence and absence of cycloheximide, in LNCaP cells. Taken together, these findings provide evidence that WAM induces apoptosis via the inhibition of HSP27/AR signaling in prostate cancer cells and is a potent anticancer candidate for prostate cancer treatment.

Nanomedicine‐Enabled Mild Photothermal Therapy Strategies for Enhanced Antitumor Treatment

Photothermal therapy (PTT) has emerged as a promising approach for tumor ablation utilizing hyperthermia offers several advantages, including non‐invasiveness, spatiotemporal controllability, and notable therapeutic efficacy. However, the clinical application of PTT is challenged by the heat diffusion. To address this, mild PTT (mPTT) has gained attention as an alternative strategy, operating at temperatures below 45 °C, with remarkable antitumor effects and minimal thermal damage to nearby normal tissues. Despite these benefits, the expression of heat shock proteins (HSPs) induces thermal resistance, which limits the therapeutic potential and practical implementation of mPTT. Nanomedicines have emerged as a solution to overcome these challenges, offering improved solubility, prolonged circulation time, enhanced tumor accumulation, and controlled cargo release, surpassing the capabilities of small molecular HSP inhibitors. Herein, it has been aimed to discuss the current landscape of photothermal agents, elucidate the underlying mechanisms of mPTT, highlight the benefits of mPTT in combination therapy, and explore the potential of nanomedicines to enhance mPTT efficacy. Additionally, future directions for the development of mPTT are presented and the challenges that are needed to be addressed are identified, with the aim of encouraging further research contributions to advance mPTT toward clinical applications.

Molecular mechanism of anticancer effect of heat shock protein 90 inhibitor BIIB021 in human bladder cancer cell line.

Bladder cancer is a type of urologic malignancy that exhibits significant morbidity, mortality, and treatment costs. Inhibition of heat shock protein 90 (HSP90) activity has been a promising pharmacological strategy for blocking of bladder cancer pathogenesis. BIIB021 is a next-generation HSP90 inhibitor which interrupts ATP hydrolysis process of HSP90 and inhibits the stabilization and correct folding of client proteins. In current study, we aimed to investigate the molecular mechanism of the anticancer activity of BIIB021 in human bladder cancer T24 cells. Our results revealed that nanomolar concentration of BIIB021 decreased viability of T24 cell. BIIB021 downregulated HSP90 expression in T24 cells and inhibited the refolding activity of luciferase in the presence of T24 cell lysate. PCR array data indicated a significant alteration in transcript levels of cancer-related genes involved in metastases, apoptotic cell death, cell cycle, cellular senescence, DNA damage and repair mechanisms, epithelial-to-mesenchymal transition, hypoxia, telomeres and telomerase, and cancer metabolism pathways in T24 cells. All findings hypothesize that BIIB021 could exhibit as effective HSP90 inhibitor in the future for treatment of bladder cancer patients.

Functionalized Nanomaterials for Inhibiting ATP-Dependent Heat Shock Proteins in Cancer Photothermal/Photodynamic Therapy and Combination Therapy.

Phototherapies induced by photoactive nanomaterials have inspired and accentuated the importance of nanomedicine in cancer therapy in recent years. During these light-activated cancer therapies, a nanoagent can produce heat and cytotoxic reactive oxygen species by absorption of light energy for photothermal therapy (PTT) and photodynamic therapy (PDT). However, PTT is limited by the self-protective nature of cells, with upregulated production of heat shock proteins (HSP) under mild hyperthermia, which also influences PDT. To reduce HSP production in cancer cells and to enhance PTT/PDT, small HSP inhibitors that can competitively bind at the ATP-binding site of an HSP could be employed. Alternatively, reducing intracellular glucose concentration can also decrease ATP production from the metabolic pathways and downregulate HSP production from glucose deprivation. Other than reversing the thermal resistance of cancer cells for mild-temperature PTT, an HSP inhibitor can also be integrated into functionalized nanomaterials to alleviate tumor hypoxia and enhance the efficacy of PDT. Furthermore, the co-delivery of a small-molecule drug for direct HSP inhibition and a chemotherapeutic drug can integrate enhanced PTT/PDT with chemotherapy (CT). On the other hand, delivering a glucose-deprivation agent like glucose oxidase (GOx) can indirectly inhibit HSP and boost the efficacy of PTT/PDT while combining these therapies with cancer starvation therapy (ST). In this review, we intend to discuss different nanomaterial-based approaches that can inhibit HSP production via ATP regulation and their uses in PTT/PDT and cancer combination therapy such as CT and ST.

A Paramagnetic Metal-Organic Framework Enhances Mild Magnetic Hyperthermia Therapy by Downregulating Heat Shock Proteins and Promoting Ferroptosis via Aggravation of Two-Way Regulated Redox Dyshomeostasis.

Mild magnetic hyperthermia therapy (MMHT) holds great potential in treating deep-seated tumors, but its efficacy is impaired by the upregulation of heat shock proteins (HSPs) during the treatment process. Herein, Lac-FcMOF, a lactose derivative (Lac-NH2 ) modified paramagnetic metal-organic framework (FcMOF) with magnetic hyperthermia property and thermal stability, has been developed to enhance MMHT therapeutic efficacy. In vitro studies showed that Lac-FcMOF aggravates two-way regulated redox dyshomeostasis (RDH) via magnetothermal-accelerated ferricenium ions-mediated consumption of glutathione and ferrocene-catalyzed generation of ∙OH to induce oxidative damage and inhibit heat shock protein 70 (HSP70) synthesis, thus significantly enhancing the anti-cancer efficacy of MMHT. Aggravated RDH promotes glutathione peroxidase 4 inactivation and lipid peroxidation to promote ferroptosis, which further synergizes with MMHT. H22-tumor-bearing mice treated with Lac-FcMOF under alternating magnetic field (AMF) demonstrated a 90.4% inhibition of tumor growth. This work therefore provides a new strategy for the simple construction of a magnetic hyperthermia agent that enables efficient MMHT by downregulating HSPs and promoting ferroptosis through the aggravation of two-way regulated RDH.

Ex vivo photothermal treatment-induced immunogenic cell death for anticancer vaccine development

Photothermal therapy is an anti-cancer strategy that induce cell death by converting light energy into heat energy. During photothermal therapy, cancer cells were treated with photothermal agents, such as indocyanine green, and irradiated with a laser. Heat stress in cancer cells results in cellular death and inflammatory responses. In the present study, we demonstrated how ex vivo photothermal (PT)-treated cells underwent immunogenic cell death. PT treatment caused significant expression of heat shock protein (HSP) 27, HSP70, and HSP90 in murine tumor cells. To evaluate the immunogenicity of heat-stressed cells, lysate from PT-treated tumor cells or water-based heated cells was pulsed to syngeneic bone-marrow-derived dendritic cells (DCs) to generate a DC-based vaccine. Administration with PT-treated tumor lysates-pulsed DC vaccine resulted in significant inhibition of tumor growth in BALB/c and C57BL/6 syngeneic tumor-bearing mice. The immunogenicity of PT-treated cancer cells was reduced in the presence of HSP inhibitors, J2, VER-155008 or 17-AAG. Our study elucidates how PT techniques have distinct mechanisms from water-based heating and might be a potentially robust and efficient solution to developing an anti-cancer vaccine.

Precise Synergistic Photothermal Therapy Guided by Accurate Temperature‐Dependent NIR‐II Fluorescence Imaging

AbstractPhotothermal therapy (PTT) is considered a promising treatment strategy for solid tumors. However, local hyperthermia (over 45°C) during PTT can cause severe side effects in neighboring healthy tissues. PTT with accurate temperature feedback is a compelling strategy to ablate tumors and reduce side effects, but it still faces challenges. Here, a new kind of phototheranostic nanoparticle, namely 17‐RF@Ag2Se is developed, enabling in vivo NIR‐II fluorescence tracking, PTT and fluorescence nanothermometry as well as synergistic heat‐shock protein (HSP) inhibition. Precise PTT with high spatiotemporal resolution is achieved with the help of the designed NIR‐II fluorescence imaging‐photothermal therapy linkage apparatus. Upon intravenous injection, 17‐RF@Ag2Se is specifically accumulated in tumors targeted by the overexpressed integrin αvβ3, which is monitored by NIR‐II fluorescence imaging of Ag2Se QDs. Further, the release of HSP inhibitor, tanespimycin (17‐AAG), enhances the thermosensitivity of tumor cells. Subsequently, the internal temperature of the tumor is precisely monitored and adjusted during PTT via the temperature‐dependent NIR‐II fluorescence feedback of Ag2Se QDs and the linkage apparatus calibration, thereby achieving efficient and safe tumor PTT. Also, the results present a new method for accurate temperature monitoring and control in vivo, which can be applied to other biomedical studies.

Mint3-depletion-induced energy stress sensitizes triple-negative breast cancer to chemotherapy via HSF1 inactivation

Given the lack of therapeutic targets, the conventional approach for managing triple-negative breast cancer (TNBC) involves the utilization of cytotoxic chemotherapeutic agents. However, most TNBCs acquire resistance to chemotherapy, thereby lowering the therapeutic outcome. In addition to oncogenic mutations in TNBC, microenvironment-induced mechanisms render chemoresistance more complex and robust in vivo. Here, we aimed to analyze whether depletion of Munc18-1 interacting protein 3 (Mint3), which activates hypoxia-inducible factor 1 (HIF-1) during normoxia, sensitizes TNBC to chemotherapy. We found that Mint3 promotes the chemoresistance of TNBC in vivo. Mint3 depletion did not affect the sensitivity of human TNBC cell lines to doxorubicin and paclitaxel in vitro but sensitized tumors of these cells to chemotherapy in vivo. Transcriptome analyses revealed that the Mint3–HIF-1 axis enhanced heat shock protein 70 (HSP70) expression in tumors of TNBC cells. Administering an HSP70 inhibitor enhanced the antitumor activity of doxorubicin in TNBC tumors, similar to Mint3 depletion. Mint3 expression was also correlated with HSP70 expression in human TNBC specimens. Mechanistically, Mint3 depletion induces glycolytic maladaptation to the tumor microenvironment in TNBC tumors, resulting in energy stress. This energy stress by Mint3 depletion inactivated heat shock factor 1 (HSF-1), the master regulator of HSP expression, via the AMP-activated protein kinase/mechanistic target of the rapamycin pathway following attenuated HSP70 expression. In conclusion, Mint3 is a unique regulator of TNBC chemoresistance in vivo via metabolic adaptation to the tumor microenvironment, and a combination of Mint3 inhibition and chemotherapy may be a good strategy for TNBC treatment.

Niacin alleviates extracellular matrix deposition in ethanol + CCl4-induced liver fibrosis through the HSP90/JAK1/STAT3 axis

Alcoholic liver fibrosis (ALF) is a reversible pathological change in the liver caused by chronic alcohol consumption and is associated with the activation of hepatic stellate cells. Recent findings suggest that niacin can lower triglyceride levels and exert potent antioxidant effects in liver damage. However, the therapeutic effects and molecular mechanisms of niacin in liver fibrosis remain unclear. Therefore, this study aimed to investigate the effects and mechanisms of niacin in ALF using in vivo and in vitro experiments. To establish a murine model of ALF, male C57BL/6N mice were fed a Lieber–DeCarli liquid diet containing 4 % (vol/vol) ethanol and injected with carbon tetrachloride twice weekly (2 mL/kg) for 8 weeks. L-02 and LX2 cells were treated with 400 μM acetaldehyde for 24 h to establish an in vitro ALF model. Serum parameters were examined to investigate the protective effects of niacin against ALF, and network pharmacology was used to identify potential targets and pathways of niacin. Niacin protects against ALF by suppressing the serum levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and alkaline phosphatase. Additionally, niacin treatment ameliorated liver fibrosis by improving the antioxidant system, inhibiting heat shock protein 90 (HSP90) activation, promoting signal transducer and activator of transcription 3 (STAT3) ubiquitination, and suppressing the JAK1/STAT3 signaling pathway. Collectively, this study provides experimental evidence that niacin protects against ALF by downregulating the HSP90/JAK1/STAT3 signaling pathway.

Synthesis and evaluation of the antitumor activity of 2-amino-4-tetrahydroindazole-substituted benzamide derivatives as HSP90 inhibitors

A new series of 2-cycloalkylamino-4–3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indazol-1-yl benzamide analogs was synthesized and evaluated for their in vitro antineoplastic activity. These compounds are analogs of 2-(4-hydroxy-cyclohexylamino)-4-(3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indazol-1-yl) benzamide (AT533), which has been previously identified as a potent inhibitor of heat shock protein 90 (HSP90). These newly synthesized analogs showed moderate-to-excellent anti-cancer activity against Eca109, A549, and MDA-MB-231 human carcinoma cells. In particular, JD-10, JD-13, and JD-14 demonstrated more potent antineoplastic effects than AT533 in tumor cells. Molecular docking studies indicated that these novel derivatives bind to the ATP-binding pocket of HSP90.

Manganese Dioxide/Gold-based Active Tumor Targeting Nanoprobes for Enhancing Photodynamic and Low-Temperature-Photothermal Combination Therapy in Lung Cancer.

Tumor drug resistance caused by the tumor microenvironment is an extremely difficult problem for researchers to solve. Nanoplatforms that integrate diagnosis and treatment have great advantages in tumor treatment, but the design and synthesis of simple and efficient nanoplatforms still face tremendous challenges. In this study, a novel Mn/Au@ir820/GA-CD133 nanoprobe was developed. The manganese dioxide/gold particles were prepared by coprecipitation/assembly, chemically coupled with CD133 antibody, and finally loaded with the photosensitive drug IR820 and the heat shock protein inhibitor Ganetespib. The nanoprobe demonstrated good tumor-targeting ability, increased the level of singlet oxygen produced from laser irradiation by effectively alleviating tumor hypoxia, and decreased the threshold of heat tolerance by downregulating the expression of HSP90 in tumor tissues. This nanoprobe successfully inhibited the growth and progression of tumor tissues in a tumor-bearing mouse model by improving the effectiveness of photodynamic and low-temperature photothermal combination therapy.

Tacrolimus reverses pemphigus vulgaris serum-induced depletion of desmoglein in HaCaT cells via inhibition of heat shock protein 27 phosphorylation

BackgroundGlucocorticoids are the first-line treatment for Pemphigus vulgaris (PV), but its serious side effects can be life-threatening for PV patients. Tacrolimus (FK506) has been reported to have an adjuvant treatment effect against PV. However, the mechanism underlying the inhibitory effect of FK506 on PV-IgG-induced acantholysis is unclear.ObjectiveThe objective of this study was to explore the effect of FK506 on desmoglein (Dsg) expression and cell adhesion in an immortalized human keratinocyte cell line (HaCaT cells) stimulated with PV sera.MethodsA cell culture model of PV was established by stimulating HaCaT cells with 5% PV sera with or without FK506 and clobetasol propionate (CP) treatment. The effects of PV sera on intercellular junctions and protein levels of p38 mitogen-activated protein kinase (p38MAPK), heat shock protein 27 (HSP27), and Dsg were assayed using western blot analysis, immunofluorescence staining, and a keratinocyte dissociation assay.ResultsPV sera-induced downregulation of Dsg3 was observed in HaCaT cells and was blocked by FK506 and/or CP. Immunofluorescence staining revealed that linear deposits of Dsg3 on the surface of HaCaT cells in the PV sera group disappeared and were replaced by granular and agglomerated fluorescent particles on the cell surface; however, this effect was reversed by FK506 and/or CP treatment. Furthermore, cell dissociation assays showed that FK506 alone or in combination with CP increased cell adhesion in HaCaT cells and ameliorated loss of cell adhesion induced by PV sera. Additionally, FK506 noticeably decreased the PV serum-induced phosphorylation of HSP 27, but had no effect on p38MAPK phosphorylation.ConclusionFK506 reverses PV-IgG induced-Dsg depletion and desmosomal dissociation in HaCaT cells, and this effect may be obtained by inhibiting HSP27 phosphorylation.

HSP70 inhibitor amplifies the bFGF‑induced release of IL‑6 in osteoblasts.

Heat shock protein 70 (HSP70) functions as an ATP‑dependent molecular chaperone under stress and is involved in protein homeostasis, folding and degradation. HSP70 inhibitors amplify TGF‑β‑stimulated VEGF synthesis in the mouse osteoblastic MC3T3‑E1 cell line. Basic fibroblast growth factor (bFGF) stimulates IL‑6 release via p38 MAPK in MC3T3‑E1 osteoblast‑like cells. In the present study, the effects of HSP70 on the bFGF‑stimulated release of IL‑6 was evaluated using MC3T3‑E1 osteoblast‑like cells. IL‑6 release and mRNA expression levels were analyzed using ELISA and reverse transcription‑quantitative PCR, respectively. Phosphorylation of p38 MAPK and HSP70 was assessed using western blotting. HSP70 inhibitor VER‑155008 significantly increased the bFGF‑stimulated release of IL‑6 in both MC3T3‑E1 osteoblastic cells and normal human osteoblasts. Furthermore, VER‑155008 significantly enhanced the mRNA expression levels of IL‑6 stimulated by bFGF. Western blotting demonstrated a significant increase in the bFGF‑stimulated phosphorylation of p38 MAPK in VER‑155008‑treated MC3T3‑E1 cells. A significant increase in the bFGF‑stimulated phosphorylation of p38 MAPK was also demonstrated in MC3T3‑E1 cells treated with YM‑08, another HSP70 inhibitor. VER‑155008 or YM‑08 did not significantly affect the expression of HSP70 with or without bFGF stimulation. Finally, the specific p38 MAPK inhibitor SB203580 markedly suppressed the enhancing effects of VER‑155008 on bFGF‑stimulated release of IL‑6. Taken together, these results indicated that HSP70 inhibitor amplified bFGF‑stimulated release of IL‑6 through p38 MAPK activation in the osteoblastic MC3T3‑E1 cell line.