Heat shock protein expression and autophagy after incomplete thermal ablation and their correlation

Roles of HSP70 in autophagic protection of cardiomyocytes induced by heat acclimation: A review

In conditions of extreme high temperature, the heart is susceptible to injury induced by heat stress, which can manifest as myocardial ischemia and hypoxia, cardiomyocyte apoptosis, oxidative damage, and inflammatory responses. The normal function of cardiomyocytes is contingent upon the maintenance of protein homeostasis, and dysregulation of protein homeostasis is the underlying cause of myocardial structural damage. Autophagy and Heat Shock Protein 70 (Hsp70) play pivotal roles in regulating cellular protein quality and mitigating stress injury. Heat acclimation has been shown to induce Hsp70 expression and provide cardiomyocyte protection. However, the mechanism by which Hsp70 mediates cardiomyocyte autophagy to exert protective effects has not been fully elucidated. The objective of this review is to synthesize the existing literature on the effects of Hsp70 on autophagy during heat exposure, to explore the potential mechanisms by which Hsp70 regulates myocardial autophagy and the molecular pathways it involves, and to provide a theoretical basis for future therapeutic strategies for cardiac diseases.

Prognostic Comparison of Complete vs. Incomplete Radiofrequency Ablation for Colorectal Liver Metastases: A Multicenter Prospective Study

BACKGROUND

Radiofrequency ablation (RFA) is a curative treatment for colorectal liver metastases (CLMs) in selected patients. NCCN guidelines recommend RFA for both unresectable and select resectable CLMs when complete ablation with adequate margins is feasible. While RFA can achieve oncologic outcomes comparable to surgery in well-selected patients, residual tumors are associated with a poorer prognosis.

OBJECTIVES

To identify predictors of residual tumor after percutaneous RFA for CLMs and evaluate their impact on overall survival (OS) and new intrahepatic metastases (NIHM).

METHODS

We prospectively included patients with CLMs who underwent percutaneous RFA from November 2019 to November 2022. Dynamic contrast-enhanced computed tomography assessed CLMs before and after RFA. Residual tumor was defined as active tumor visible immediately post-ablation or within 4-8 weeks, within 1 cm of the ablation zone. Data from three centers formed a developmental cohort, validated with patients from a fourth center. Cox regression and Kaplan-Meier analysis assessed local tumor progression-free survival (LTPFS), NIHM, and OS.

RESULTS

Among 200 patients (mean age 61 years, 126 men) with 410 tumors, independent predictors of residual tumors included perivascular tumor location (odds ratio [OR] = 6.673), tumor size ≥ 20 mm (OR = 3.925), and minimal ablative margin (OR = 0.599). These factors also predicted LTPFS. NIHM was more frequent in the residual tumor group than in the complete RFA (cRFA) group (p = 0.002). Median OS was 45 months, shorter in the residual tumor group (30 vs. 48 months, p = 0.009). Patients with NIHM who received transarterial chemoembolization combined with hepatic arterial infusion chemotherapy had a median OS of 43 months, compared to 34 months with RFA alone (p = 0.039).

CONCLUSIONS

A non-perivascular tumor location, tumor size < 20 mm, and a sufficient ablation margin are essential for achieving complete RFA. Residual tumors are associated with increased NIHM and shorter OS.

Ac-HSP20 regulates autophagy and promotes the encystation of Acanthamoeba castellanii by inhibiting the PI3K/AKT/mTOR signaling pathway

BACKGROUND

The encystation of Acanthamoeba castellanii has important ecological and medical significance. Blocking encystation is the key to preventing transmission and curing infections caused by A. castellanii. The formation of autophagosomes is one of the most important changes that occur during the encystation of Acanthamoeba. Our previous studies have shown that the heat shock protein 20 of A. castellanii (Ac-HSP20) is involved in its encystation. This study aimed to determine the role and mechanism of Ac-HSP20 in regulating autophagy involved in the encystation of A. castellanii.

METHODS

Immunofluorescence assay, western blotting and transmission electron microscopy were used to analyze the dynamic changes in autophagy during the initiation and continuation of encystation. The knockdown of Ac-HSP20 was performed to clarify its regulation of encystation and autophagy and to elucidate the molecular mechanism by which Ac-HSP20 participates in autophagy to promote cyst maturation.

RESULTS

The encystation rates and autophagosomes were significantly decreased by treatment with the autophagy inhibitor 3-MA. The autophagy marker LC3B and autophagic lysosomes increased with the induced duration of encystation and reached the maximum at 48 h. The encystation rate, LC3B expression and autophagosomes decreased when Ac-HSP20 was knocked down by siRNA transfection. In addition, the expression levels of Ac-HSP20 and LC3B increased and the expressions of p-AKT and p-mTOR decreased after 48 h of encystation without knockdown. However, the expressions of p-AKT and p-mTOR increased while the expression of LC3B decreased under the knockdown of Ac-HSP20. Furthermore, the protein expression of LC3B increased when the PI3K/AKT/mTOR signaling pathway was inhibited but decreased when the pathway was activated.

CONCLUSIONS

The results demonstrated that autophagy is positively correlated with the encystation of A. castellanii, and Ac-HSP20 regulates autophagy to maintain the homeostasis of A. castellanii by inhibiting the PI3K /AKT /mTOR signaling pathway, thus promoting the maturation and stability of encystation.

Camrelizumab, apatinib and hepatic artery infusion chemotherapy combined with microwave ablation for advanced hepatocellular carcinoma

BACKGROUND

Hepatic arterial infusion chemotherapy and camrelizumab plus apatinib (TRIPLET protocol) is promising for advanced hepatocellular carcinoma (Ad-HCC). However, the usefulness of microwave ablation (MWA) after TRIPLET is still controversial.

AIM

To compare the efficacy and safety of TRIPLET alone (T-A) vs TRIPLET-MWA (T-M) for Ad-HCC.

METHODS

From January 2018 to March 2022, 217 Ad-HCC patients were retrospectively enrolled. Among them, 122 were included in the T-A group, and 95 were included in the T-M group. A propensity score matching (PSM) was applied to balance bias. Overall survival (OS) was compared using the Kaplan-Meier curve with the log-rank test. The overall objective response rate (ORR) and major complications were also assessed.

RESULTS

After PSM, 82 patients were included both the T-A group and the T-M group. The ORR (85.4%) in the T-M group was significantly higher than that (65.9%) in the T-A group (P < 0.001). The cumulative 1-, 2-, and 3-year OS rates were 98.7%, 93.4%, and 82.0% in the T-M group and 85.1%, 63.1%, and 55.0% in the T-A group (hazard ratio = 0.22; 95% confidence interval: 0.10-0.49; P < 0.001). The incidence of major complications was 4.9% (6/122) in the T-A group and 5.3% (5/95) in the T-M group, which were not significantly different (P = 1.000).

CONCLUSION

T-M can provide better survival outcomes and comparable safety for Ad-HCC than T-A.

Hsp90α and cell death in cancers: a review

Heat shock protein 90α (Hsp90α), an important molecular chaperone, plays a crucial role in regulating the activity of various intracellular signaling pathways and maintaining the stability of various signaling transduction proteins. In cancer, the expression level of Hsp90α is often significantly upregulated and is recognized as one of the key factors in cancer cell survival and proliferation. Cell death can help achieve numerous purposes, such as preventing aging, removing damaged or infected cells, facilitating embryonic development and tissue repair, and modulating immune response. The expression of Hsp90α is closely associated with specific modes of cell death including apoptosis, necrotic apoptosis, and autophagy-dependent cell death, etc. This review discusses the new results on the relationship between expression of Hsp90α and cell death in cancer. Hsp90α is frequently overexpressed in cancer and promotes cancer cell growth, survival, and resistance to treatment by regulating cell death, rendering it a promising target for cancer therapy.

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.

Mitochondrial ROS driven by NOX4 upregulation promotes hepatocellular carcinoma cell survival after incomplete radiofrequency ablation by inducing of mitophagy via Nrf2/PINK1

BACKGROUND

The recurrence of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) remains a major clinical problem. Cells that survive the sublethal heat stress that is induced by incomplete RFA are the main source of HCC relapse. Heat stress has long been reported to increase intracellular reactive oxygen species (ROS) generation. Although ROS can induce apoptosis, a pro-survival effect of ROS has also been demonstrated. However, the role of ROS in HCC cells exposed to sublethal heat stress remains unclear.

METHODS

HepG2 and HuH7 cells were used for this experiment. Insufficient RFA was performed in cells and in a xenograft model. ROS and antioxidant levels were measured. Apoptosis was analyed by Annexin-V/PI staining and flow cytometry. Protein expression was measured using western blotting. Colocalization of lysosomes and mitochondria was analyzed to assess mitophagy. Corresponding activators or inhibitors were applied to verify the function of specific objectives.

RESULTS

Here,we showed that sublethal heat stress induced a ROS burst, which caused acute oxidative stress. This ROS burst was generated by mitochondria, and it was initiated by upregulated NOX4 expression in the mitochondria. N-acetylcysteine (NAC) decreased HCC cell survival under sublethal heat stress conditions in vivo and in vitro. NOX4 triggers the production of mitochondrial ROS (mtROS), and NOX4 inhibitors or siNOX4 also decreased HCC cell survival under sublethal heat stress conditions in vitro. Increased mtROS trigger PINK1-dependent mitophagy to eliminate the mitochondria that are damaged by sublethal heat stress and to protect cells from apoptosis. Nrf2 expression was elevated in response to this ROS burst and mediated the ROS burst-induced increase in PINK1 expression after sublethal heat stress.

CONCLUSION

These data confirmed that the ROS burst that occurs after iRFA exerted a pro-survival effect. NOX4 increased the generation of ROS by mitochondria. This short-term ROS burst induced PINK1-dependent mitophagy to eliminate damaged mitochondria by increasing Nrf2 expression.

The alteration of N6-methyladenosine (m6A) modification at the transcriptome-wide level in response of heat stress in bovine mammary epithelial cells

Background

Heat stress has a substantial negative economic impact on the dairy industry. N6-methyladenosine (m6A) is the most common internal RNA modification in eukaryotes and plays a key role in regulating heat stress response in animals. In dairy cows, however, this modification remains largely unexplored. Therefore, we examined the effects of heat stress on the m6A modification and gene expression in bovine mammary epithelial cells to elucidate the mechanism of heat stress response. In this study, Mammary alveolar cells-large T antigen (MAC-T) cells were incubated at 37 °C (non-heat stress group, NH) and 40 °C (heat stress group, H) for 2 hours, respectively. HSP70, HSF1, BAX and CASP3 were up regulated in H group compared with those in the NH group.

Results

Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were conducted to identify m6A peaks and to produce gene expression data of MAC-T cells in the H and NH groups. In total, we identified 17,927 m6A peaks within 9355 genes in the H group, and 18,974 peaks within 9660 genes in the NH groups using MeRIP-seq. Compared with the NH group, 3005 significantly differentially enriched m6A peaks were identified, among which 1131 were up-regulated and 1874 were down-regulated. In addition, 1502 significantly differentially expressed genes were identified using RNA-seq, among which 796 were up-regulated and 706 were down-regulated in the H group compared to the NH group. Furthermore, 199 differentially expressed and synchronously differentially methylated genes were identified by conjoint analysis of the MeRIP-seq and RNA-seq data, which were subsequently divided into four groups: 47 hyper-up, 53 hyper-down, 59 hypo-up and 40 hypo-down genes. In addition, GO enrichment and KEGG analyses were used to analyzed the potential functions of the genes in each section.

Conclusion

The comparisons of m6A modification patterns and conjoint analyses of m6A modification and gene expression profiles suggest that m6A modification plays a critical role in the heat stress response by regulating gene expression.

Progression of hepatocellular carcinoma after radiofrequency ablation: Current status of research

Hepatocellular carcinoma (HCC) remains an important disease for health care systems in view of its high morbidity, mortality, and increasing incidence worldwide. Radiofrequency ablation (RFA) is preferred to surgery as a local treatment for HCC because it is safer, less traumatic, less painful, better tolerated, causes fewer adverse reactions, and allows more rapid postoperative recovery. The biggest shortcoming of RFA when used to treat HCC is the high incidence of residual tumor, which is often attributed to the vascular thermal deposition effect, the wide infiltration zone of peripheral venules, and the distance between satellite foci and the main focus of the cancer. Recurrence and progression of the residual tumor is the most important determinant of the prognosis. Therefore, it is important to be aware of the risk of recurrence and to improve the efficacy of RFA. This review summarizes the relevant literature and the possible mechanisms involved in progression of HCC after RFA. Current studies have demonstrated that multimodal treatments which RFA combined with other anti-cancer approaches can prevent progression of HCC after RFA.

An Overview of Hepatocellular Carcinoma After Insufficient Radiofrequency Ablation

Radiofrequency ablation (RFA) is a commonly used treatment for hepatocellular carcinoma (HCC), however, various complex conditions in clinical practice may lead to insufficient radiofrequency ablation (IRFA), allowing residual HCC to survive. In clinical practice and laboratory models, IRFA plays an important role in rapid tumor progression. Therefore, targeting the residual HCC and avoiding IRFA were worthwhile methods. A deeper understanding of IRFA is required; IRFA contributes to the improvement of proliferative activity, migration rates, and invasive capacity, and this may be due to the involvement of multiple complex processes or proteins, including epithelial mesenchymal transitions (EMTs), cancer stem cells (CSCs), autophagy, heat shock proteins (HSPs), changes of non-tumor cells and extracellular matrix, altered immune microenvironment, hypoxia-inducible factors (HIFs), growth factors, epigenetic alterations, and metabolic reprogramming. We focus on the processes of the above mechanisms and possible therapeutic approach, with a review of the literature. Additionally, we recapitulated the construction methods of various experimental models of IRFA (in vivo and in vitro).

The Disassociation of the A20/HSP90 Complex via Downregulation of HSP90 Restores the Effect of A20 Enhancing the Sensitivity of Hepatocellular Carcinoma Cells to Molecular Targeted Agents

NF-κB (nuclear factor κB) is a regulator of hepatocellular cancer (HCC)-related inflammation and enhances HCC cells' resistance to antitumor therapies by promoting cell survival and anti-apoptosis processes. In the present work, we demonstrate that A20, a dominant-negative regulator of NF-κB, forms a complex with HSP90 (heat-shock protein 90) and causes the disassociation of the A20/HSP90 complex via downregulation of HSP90. This process restores the antitumor activation of A20. In clinical specimens, the expression level of A20 did not relate with the outcome in patients receiving sorafenib; however, high levels of HSP90 were associated with poor outcomes in these patients. A20 interacted with and formed complexes with HSP90. Knockdown of HSP90 and treatment with an HSP90 inhibitor disassociated the A20/HSP90 complex. Overexpression of A20 alone did not affect HCC cells. Downregulation of HSP90 combined with A20 overexpression restored the effect of A20. Overexpression of A20 repressed the expression of pro-survival and anti-apoptosis-related factors and enhanced HCC cells' sensitivity to sorafenib. These results suggest that interactions with HSP90 could be potential mechanisms of A20 inactivation and disassociation of the A20/HSP90 complex and could serve as a novel strategy for HCC treatment.

Selenium-Alleviated Testicular Toxicity by Modulating Inflammation, Heat Shock Response, and Autophagy Under Oxidative Stress in Lead-Treated Chickens

Lead (Pb), a toxic pollutant, is toxic to the testis. However, biological events during testicular Pb poisoning were not well understood. Selenium (Se) has the ability to antagonize Pb toxicity. The purpose of this research was to clarify the relief mechanism of Se on testicular toxicity of Pb from the perspective of oxidative stress, inflammation, heat shock response, and autophagy in a chicken model. Sixty male Hyline chickens (7-day-old) were randomly assigned into four groups. The feeding program consisted of a commercial diet, a Se-supplemented diet (1 mg kg^-1 Se), a Pb-supplemented diet (350 mg L^-1 Pb), and a Se- and Pb-supplemented diet, respectively. On the 12th week, serums were collected to measure testosterone level and testes were removed to determine testis weight, histological structure, Pb and Se concentrations, oxidative stress indicators, and mRNA and protein expression of inflammatory cytokines, heat shock proteins, and autophagy-related genes. The results showed that Pb poisoning changed the histological structure of testes; decreased serum testosterone level, testis weight, catalase, glutathione-s-transferase, and total antioxidative capacity activities; increased hydrogen peroxide content; inhibited interleukin (IL)-2 and mammalian target of rapamycin expression; and promoted IL-4, IL-12β, heat shock proteins, Beclin 1, Dynein, autophagy-related proteins 5, light chain 3 (LC3)-I, and LC3-II expression in the testes of chickens. Se intervention mitigated the aforementioned alterations induced by Pb. In conclusion, Pb led to oxidative stress, which triggered inflammation, heat shock response, and autophagy. Se administration mitigated testicular toxicity of Pb mainly by mitigating oxidative stress in male chickens.

Interventional Radiology Image-Guided Locoregional Therapies (LRTs) and Immunotherapy for the Treatment of HCC

Image-guided locoregional therapies (LRTs) are a crucial asset in the treatment of hepatocellular carcinoma (HCC), which has proven to be characterized by an impaired antitumor immune status. LRTs not only directly destroy tumor cells but also have an immunomodulating role, altering the tumor microenvironment with potential systemic effects. Nevertheless, the immune activation against HCC induced by LRTs is not strong enough on its own to generate a systemic significant antitumor response, and it is incapable of preventing tumor recurrence. Currently, there is great interest in the possibility of combining LRTs with immunotherapy for HCC, as this combination may result in a mutually beneficial and synergistic relationship. On the one hand, immunotherapy could amplify and prolong the antitumoral immune response of LRTs, reducing recurrence cases and improving outcome. On the other hand, LTRs counteract the typical immunosuppressive HCC microenvironment and status and could therefore enhance the efficacy of immunotherapy. Here, after reviewing the current therapeutic options for HCC, we focus on LRTs, describing for each of them the technique and data on its effect on the immune system. Then, we describe the current status of immunotherapy and finally report the recently published and ongoing clinical studies testing this combination.

CEUS-Based Radiomics Can Show Changes in Protein Levels in Liver Metastases After Incomplete Thermal Ablation

Objective

To investigate the ability of contrast-enhanced ultrasound (CEUS)-based radiomics combined with machine learning to detect early protein changes after incomplete thermal ablation.

Methods

HCT-26 colorectal adenoma cells were engrafted into the livers of 80 mice, which were randomly divided into 4 groups for palliative laser ablation. Changes in heat shock protein (HSP) and apoptosis-related protein expression in the tumors were assessed. SCID mice subjected to CEUS and ultrasonography were divided into training (n=56) and test (n=24) datasets. Then, 102 features from seven feature groups were extracted. We use the least absolute shrinkage and selection operator (LASSO) feature selection method to fit the machine learning classifiers. The feature selection methods and four classifiers were combined to determine the best prediction model.

Results

The areas under the receiver-operating characteristic curves (AUCs) of the classifiers in the test dataset ranged from 0.450 to 0.932 (median: 0.721). The best score was obtained from the model in which the omics data of CEUS was analyzed in the arterial phase by random forest (RF) classification.

Conclusions

A machine learning model, in which radiomics characteristics are extracted by multimodal ultrasonography, can accurately, rapidly and noninvasively identify protein changes after ablation.

Immunological Effects of Histotripsy for Cancer Therapy

Cancer is the second leading cause of death worldwide despite major advancements in diagnosis and therapy over the past century. One of the most debilitating aspects of cancer is the burden brought on by metastatic disease. Therefore, an ideal treatment protocol would address not only debulking larger primary tumors but also circulating tumor cells and distant metastases. To address this need, the use of immune modulating therapies has become a pillar in the oncology armamentarium. A therapeutic option that has recently emerged is the use of focal ablation therapies that can destroy a tumor through various physical or mechanical mechanisms and release a cellular lysate with the potential to stimulate an immune response. Histotripsy is a non-invasive, non-ionizing, non-thermal, ultrasound guided ablation technology that has shown promise over the past decade as a debulking therapy. As histotripsy therapies have developed, the full picture of the accompanying immune response has revealed a wide range of immunogenic mechanisms that include DAMP and anti-tumor mediator release, changes in local cellular immune populations, development of a systemic immune response, and therapeutic synergism with the inclusion of checkpoint inhibitor therapies. These studies also suggest that there is an immune effect from histotripsy therapies across multiple murine tumor types that may be reproducible. Overall, the effects of histotripsy on tumors show a positive effect on immunomodulation.

A potential mechanism associated with lead-induced spermatogonia and Leydig cell toxicity and mitigative effect of selenium in chicken

Lead (Pb) is a toxic heavy metal pollutants and can damage male reproductive function. Selenium (Se) possesses an ability of antagonizing Pb toxicity. However, biological events in the process of Pb toxicity and mitigative effect of Se are not well understood. The aim of present research was to investigate potential mechanism of Se against Pb toxicity from the perspective of oxidative stress, heat shock response and autophagy in the spermatogonia and Leydig cell of chicken. The cells from one-day-old male Hyline chickens were treated with Se (0.5 μmol/L) and/or Pb (20 μmol/L) for 24 h, respectively. Cell viability, cell ultrastucture, Pb and Se concentrations, testosterone level, oxidative stress indicators and relative expression of heat shock proteins (HSPs) and autophagy-related genes were measured. The results showed that spermatogonia was more tolerant to Pb than Leydig cell; cell injury was confirmed via histological assessment, cell viability and testosterone level; oxidative stress was further indicated by the decrease of catalase, glutathione peroxidase, glutathione-s-transferase and superoxide dismutase activities and the increase of malondialdehyde and reactive oxygen species contents. Pb increased expression of HSPs (27, 40, 60, 70 and 90). Meanwhile Pb induced autophagy through up-regulation of autophagy-related proteins 5, Beclin 1, Dynein, light chain 3 (LC3)-I and LC3-II and down-regulation of mammalian target of rapamycin in two type cells of chicken. However, Se intervention mitigated the aforementioned alterations caused by Pb. In conclusion, Pb led to oxidative stress, which triggered heat shock response and autophagy; Se administration mitigated reproductive toxicity of Pb through strengthening antioxidant defense in the spermatogonia and Leydig cell of chicken.

Impaired autophagy following ex vivo heating at physiologically relevant temperatures in peripheral blood mononuclear cells from elderly adults

With the increasing threat of climate change and the accompanying rise in the frequency and severity of extreme heat events, there are growing health concerns for heat-vulnerable elderly adults. Elderly adults are at increased risk of developing heat-related injuries, in part due to age-related declines in thermoregulatory and cellular function. Regarding the latter, the process of autophagy is activated as a cellular protective mechanism to counter heat-induced stress, but the extent that heat stress activates autophagy in elderly adults is not known. Further, the interplay between autophagy, the heat shock response (HSR), the acute inflammatory response, and apoptosis remains poorly understood in elderly adults. Therefore, the purpose of this study was to examine changes in autophagy, the HSR, inflammation, and apoptosis following increasing levels of ex vivo heat stress representative of physiologically relevant increases in body core temperatures (37-41 °C). Whole blood from 20 elderly adults (72 ± 4 years; 14 men, 6 women) was heated (via water immersion) to temperatures representative of normal resting conditions (normothermia; 37 °C), in addition to moderate and severe heat stress conditions (39, and 41 °C, respectively) for 90 min. Peripheral blood mononuclear cells (PBMC) were isolated and protein markers of autophagy, the HSR, acute inflammation, and apoptosis were examined. No significant increases in markers of autophagy or the HSR were observed following any temperature condition. However, an increase in acute inflammation was observed above baseline following moderate heat stress (39 °C), with further increases in inflammation and apoptosis observed during severe heat stress (41 °C). Our findings indicate that PBMCs from elderly adults do not exhibit increases in autophagy or the HSR following severe heat stress, potentially contributing to the elevated risk of cellular dysfunction seen in elderly adults during heat stress.

Trametenolic Acid B Triggers HSP90AA4P and Autophagy in HepG2/2.2.15 Cells by Proteomic Analysis

Our previous studies have demonstrated that trametenolic acid B (TAB) extracted from the Laetiporus sulphureus (Fr.) Murrill owned effective anti-proliferation of HepG2/2.215 cells and induced autophagy activity. The present aim was to further investigate its mechanisms involved by proteomic analysis. The iTRAQ of TAB on HepG2/2.215 was carried out and the western blot was used to verify the results of the proteomics analysis. According to the peptide segment quantitative standard (FDR ≤ 1%), a total of 5324 proteins were identified in HepG2/2.215 by proteomic analysis. The results identified that the major up-regulated proteins were HSP90AA4P, MYB, SERPINE1, and down-regulated proteins were Rho C, SERPINA1, and PIK3R4, which were related to PI3K/Akt signaling pathway, cell metastasis, and autophagy. HSP90AA4P and Rho C's proteomics analysis were further confirmed by the western blot. The proteomic results demonstrated that the anti-hematoma effect of TAB was closely related to the increase of HSP90AA4P protein expressions and autophagy, which may be a critical target of TAB, which was expected to be a candidate drug for the treatment liver cancer.

The role of HSP90 molecular chaperones in hepatocellular carcinoma

Misfolded proteins have enhanced formation of toxic oligomers and nonfunctional protein copies lead to recruiting wild-type protein types. Heat shock protein 90 (HSP90) is a molecular chaperone generated by cells that are involved in many cellular functions through regulation of folding and/or localization of large multi-protein complexes as well as client proteins. HSP90 can regulate a number of different cellular processes including cell proliferation, motility, angiogenesis, signal transduction, and adaptation to stress. HSP90 makes the mutated oncoproteins able to avoid misfolding and degradation and permits the malignant transformation. As a result, HSP90 is an important factor in several signaling pathways associated with tumorigenicity, therapy resistance, and inhibiting apoptosis. Clinically, the upregulation of HSP90 expression in hepatocellular carcinoma (HCC) is linked with advanced stages and inappropriate survival in cases suffering from this kind of cancer. The present review comprehensively assesses HSP90 functions and its possible usefulness as a potential diagnostic biomarker and therapeutic option for HCC.

Combination of HSP90 and autophagy inhibitors promotes hepatocellular carcinoma apoptosis following incomplete thermal ablation

The present study evaluated the effect of combining inhibitors (17-AAG) of heat shock protein 90 (HSP90) and autophagy (3-MA) on apoptosis using an incomplete thermal ablation animal model. A total of 28 orthotopic mice with hepatocellular carcinoma were randomly divided into 4 groups to receive different drug interventions. Following palliative laser ablation, changes in autophagy, apoptosis and Akt/mTOR expression levels were assessed in tumors. Compared with the controls, the 17-AAG-treated mice exhibited significantly decreased expression levels of phosphorylated (p)-Akt and p-mTOR with enhanced autophagy and apoptosis; no marked increases in the expression levels of p-Akt and p-mTOR were observed in the 3-MA-treated mice, with no significant changes in autophagy; however, apoptosis was enhanced. No significant decreases in p-Akt and p-mTOR or any increase in autophagy were observed in the mice receiving a combination of 17-AAG and 3-MA, but they did exhibit a marked increase in apoptosis. Compared with 17-AAG alone, the combination of 17-AAG and 3-MA resulted in a marked increase in apoptosis without enhanced autophagy. In the incomplete ablation model, the effects of autophagy and apoptosis are antagonistic. The combined use of 17-AAG and 3-MA can significantly promote apoptosis and is worthy of further study.