Functional Compartmentalization of HSP60-Survivin Interaction between Mitochondria and Cytosol in Cancer Cells

Potential of Natural Products in the Treatment of Glioma: Focus on Molecular Mechanisms

Despite the waning of traditional treatments for glioma due to possible long-term issues, the healing possibilities of substances derived from nature have been reignited in the scientific community. These natural substances, commonly found in fruits and vegetables, are considered potential alternatives to pharmaceuticals, as they have been shown in prior research to impact pathways surrounding cancer progression, metastases, invasion, and resistance. This review will explore the supposed molecular mechanisms of different natural components, such as berberine, curcumin, coffee, resveratrol, epigallocatechin-3-gallate, quercetin, tanshinone, silymarin, coumarin, and lycopene, concerning glioma treatment. While the benefits of a balanced diet containing these compounds are widely recognized, there is considerable scope for investigating the efficacy of these natural products in treating glioma.

Molecular Chaperonin HSP60: Current Understanding and Future Prospects

Molecular chaperones are highly conserved across evolution and play a crucial role in preserving protein homeostasis. The 60 kDa heat shock protein (HSP60), also referred to as chaperonin 60 (Cpn60), resides within mitochondria and is involved in maintaining the organelle's proteome integrity and homeostasis. The HSP60 family, encompassing Cpn60, plays diverse roles in cellular processes, including protein folding, cell signaling, and managing high-temperature stress. In prokaryotes, HSP60 is well understood as a GroEL/GroES complex, which forms a double-ring cavity and aids in protein folding. In eukaryotes, HSP60 is implicated in numerous biological functions, like facilitating the folding of native proteins and influencing disease and development processes. Notably, research highlights its critical involvement in sustaining oxidative stress and preserving mitochondrial integrity. HSP60 perturbation results in the loss of the mitochondria integrity and activates apoptosis. Currently, numerous clinical investigations are in progress to explore targeting HSP60 both in vivo and in vitro across various disease models. These studies aim to enhance our comprehension of disease mechanisms and potentially harness HSP60 as a therapeutic target for various conditions, including cancer, inflammatory disorders, and neurodegenerative diseases. This review delves into the diverse functions of HSP60 in regulating proteo-homeostasis, oxidative stress, ROS, apoptosis, and its implications in diseases like cancer and neurodegeneration.

Fatal attractions that trigger inflammation and drive atherosclerotic disease

BACKGROUND

Atherosclerosis is the salient, underlying cause of cardiovascular diseases, such as arrhythmia, coronary artery disease, cardiomyopathy, pulmonary embolism and myocardial infarction. In recent years, atherosclerosis pathophysiology has evolved from a lipid-based to an inflammation-centric ideology.

METHODS

This narrative review is comprised of review and original articles that were found through the PubMed search engine. The following search terms or amalgamation of terms were used: "cardiovascular disease," "atherosclerosis," "inflammation," "GRP78," "Hsp60," "oxidative low-density lipoproteins," "aldehyde dehydrogenase," "β2-glycoprotein," "lipoprotein lipase A," "human cytomegalovirus." "SARS-CoV-2," "chlamydia pneumonia," "autophagy," "thrombosis" and "therapeutics."

RESULTS

Emerging evidence supports the concept that atherosclerosis is associated with the interaction between cell surface expression of stress response chaperones, including GRP78 and Hsp60, and their respective autoantibodies. Moreover, various other autoantigens and their autoantibodies have displayed a compelling connection with the development of atherosclerosis, including oxidative low-density lipoproteins, aldehyde dehydrogenase, β2-glycoprotein and lipoprotein lipase A. Atherosclerosis progression is also concurrent with viral and bacterial activators of various diseases. This narrative review will focus on the contributions of human cytomegalovirus as well as SARS-CoV-2 and chlamydia pneumonia in atherosclerosis development. Notably, the interaction of an autoantigen with their respective autoantibodies or the presence of a foreign antigen can enhance inflammation development, which leads to atherosclerotic lesion progression.

CONCLUSION

We will highlight and discuss the complex role of the interaction between autoantigens and autoantibodies, and the presence of foreign antigens in the development of atherosclerotic lesions in relationship to pro-inflammatory responses.

Heat Shock Proteins, a Double-Edged Sword: Significance in Cancer Progression, Chemotherapy Resistance and Novel Therapeutic Perspectives

Heat shock proteins (Hsps) are involved in one of the adaptive mechanisms protecting cells against environmental and metabolic stress. Moreover, the large role of these proteins in the carcinogenesis process, as well as in chemoresistance, was noticed. This review aims to draw attention to the possibilities of using Hsps in developing new cancer therapy methods, as well as to indicate directions for future research on this topic. In order to discuss this matter, a thorough review of the latest scientific literature was carried out, taking into account the importance of selected proteins from the Hsp family, including Hsp27, Hsp40, Hsp60, Hsp70, Hsp90 and Hsp110. One of the more characteristic features of all Hsps is that they play a multifaceted role in cancer progression, which makes them an obvious target for modern anticancer therapy. Some researchers emphasize the importance of directly inhibiting the action of these proteins. In turn, others point to their possible use in the design of cancer vaccines, which would work by inducing an immune response in various types of cancer. Due to these possibilities, it is believed that the use of Hsps may contribute to the progress of oncoimmunology, and thus help in the development of modern anticancer therapies, which would be characterized by higher effectiveness and lower toxicity to the patients.

The Interplay between Heat Shock Proteins and Cancer Pathogenesis: A Novel Strategy for Cancer Therapeutics

Heat shock proteins (HSPs) are developmentally conserved families of protein found in both prokaryotic and eukaryotic organisms. HSPs are engaged in a diverse range of physiological processes, including molecular chaperone activity to assist the initial protein folding or promote the unfolding and refolding of misfolded intermediates to acquire the normal or native conformation and its translocation and prevent protein aggregation as well as in immunity, apoptosis, and autophagy. These molecular chaperonins are classified into various families according to their molecular size or weight, encompassing small HSPs (e.g., HSP10 and HSP27), HSP40, HSP60, HSP70, HSP90, and the category of large HSPs that include HSP100 and ClpB proteins. The overexpression of HSPs is induced to counteract cell stress at elevated levels in a variety of solid tumors, including anticancer chemotherapy, and is closely related to a worse prognosis and therapeutic resistance to cancer cells. HSPs are also involved in anti-apoptotic properties and are associated with processes of cancer progression and development, such as metastasis, invasion, and cell proliferation. This review outlines the previously mentioned HSPs and their significant involvement in diverse mechanisms of tumor advancement and metastasis, as well as their contribution to identifying potential targets for therapeutic interventions.

The proteomics analysis of extracellular vesicles revealed the possible function of heat shock protein 60 in Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric diseases, including gastritis and gastric cancer. Heat shock protein 60 (HSP60) is a chaperone protein involved in various cellular processes and has been implicated in the immune response to bacterial infections. Extracellular vesicles (EVs) containing various protein components play important roles in cell communication. In the present study, a systematic proteomic analysis of EVs obtained from H. pylori infected cells was performed and the EV-derived HSP60 function was studied.

METHODS

EVs were evaluated by nanoparticle tracking analysis, transmission electron microscopy and western blotting. The recognized protein components were quantified by label-free proteomics and subjected to bioinformatics assays. The expression of HSP60 in EVs, host cells and gastric cancers infected by H. pylori was determined by western blotting and immunohistochemical, respectively. In addition, the apoptotic regulation mechanisms of HSP60 in H. pylori infection were analyzed by western blotting and flow cytometry.

RESULTS

A total of 120 important differential proteins were identified in the EVs from H. pylori-infected cells and subjected to Gene Ontology analysis. Among them, CD63, HSP-70 and TSG101 were verified via western blotting. Moreover, HSP60 expression was significantly increased in the EVs from H. pylori-infected GES-1 cells. H. pylori infection promoted an abnormal increase in HSP60 expression in GES-1 cells, AGS cells, gastric mucosa and gastric cancer. In addition, knockdown of HSP60 suppressed the apoptosis of infected cells and the expression of Bcl2, and promoted the upregulation of Bax.

CONCLUSION

This study provides a comprehensive proteomic profile of EVs from H. pylori-infected cells, shedding light on the potential role of HSP60 in H. pylori infection. The findings underscore the significance of EV-derived HSP60 in the pathophysiology of H. pylori-associated diseases.

High expression of HSP60 and survivin predicts poor prognosis for oral squamous cell carcinoma patients

BACKGROUND

HSP60 is a heat shock proteins (HSPs) family member and help mitochondrial protein to fold correctly. Survivin is one of the inhibitors of apoptosis protein family member, which plays a significant part in cancer progression. They were capable of forming HSP60-survivin complexes and involved in the development of various tumors.

METHODS

The Cancer Genome Atlas (TCGA) database demonstrated that HSP60 and survivin and their correlation on mRNA expression level with OSCC patients. Besides, expression of HSP60 and survivin proteins was studied utilizing immunohistochemistry in tissue microarrays (TMA) in OSCC and in adjacent non-cancerous squamous epithelium (Non-CCSE) tissues.

RESULTS

Significantly increased levels of HSP60 and survivin in most cancers compared to normal tissue by pan-cancer analysis. HSP60 and survivin proved a significantly increased expression in OSCC samples compared to Non-CCSE both on mRNA and protein (both P < 0.05). Additionally, elevated HSP60 displayed a positive correlation with survivin in terms of mRNA and protein expression levels (all P < 0.001). Patients with OSCC who had advanced clinical stage or lymph node metastasis (LNM) showed higher HSP60 expression (P = 0.004, P = 0.006, respectively). Higher levels of the proteins HSP60 and survivin were significantly inversely correlated relationship with OSCC patients' overall survival rates in multivariate survival analysis (P = 0.018, P = 0.040). From the above results, overexpression of HSP60 and survivin protein may serve as independent biomarkers predicting poor prognosis in OSCC.

CONCLUSIONS

Elevated HSP60 and survivin might be served as novel poor prognosis biomarkers for surgically resected OSCC patients.

PRM-based quantitative proteomics analysis of altered HSP abundance in villi and decidua of patients with early missed abortion

OBJECTIVE

In this study, we aimed to identify differentially expressed heat shock protein (HSP) profiles in the villi and decidua from patients with early missed abortion (EMA).

METHODS

By using high-throughput and high-precision parallel reaction monitoring (PRM)-based targeted proteomics techniques, this study examined the abundance of HSPs in the villi and decidua of 10 patients with EMA and 10 controls. Moreover, the abundance of 3 HSPs in the villi of another 22 patients with EMA and 22 controls was verified with Western blotting and immunohistochemistry (IHC).

RESULTS

There were potential differences in the abundance of 16 HSPs and 42 polypeptides in human villi and decidua compared with those of the control group. Among them, HSP90AB1, HSPD1 and HSPA13 were downregulated in abundance in villi of patients with EMA, with a statistically significant difference, which was consistent with the verification results of Western blots and IHC.

CONCLUSION

Using a PRM-based targeted proteomics technique, this study is the first to screen and quantitatively analyze the expression profile of HSPs in the villi and decidua of patients with EMA. The significant downregulation of HSP90AB1, HSPD1 and HSPA13 was found to have a potentially intimate association with the occurrence of EMA. The findings in our study may provide novel potential research targets related to HSPs for the pathogenesis, prevention and treatment of EMA.

Clinicopathologic Significance of Heat Shock Protein 60 as a Survival Predictor in Colorectal Cancer

The role of heat shock protein 60 (HSP60), a mitochondrial chaperone, in tumor progression or its anti-tumor effects remains controversial. This study aimed to confirm the possibility of using HSP60 as a prognostic marker in patients with colorectal cancer (CRC), considering TNM classification for precise prediction. HSP60 expression increased with differentiation and p53 mutations in patients. However, compared to patients with high HSP60 expression, patients with low HSP60 expression had event-free survival and disease-specific survival hazard ratios (HRs) of 1.42 and 1.69, respectively. Moreover, when the survival rate was analyzed by combining TNM classification and HSP60 expression, the prognosis was poor, particularly when HSP60 expression was low in the late/advanced stage. This pattern was also observed with HSP family D member 1, HSPD1, the gene that encodes HSP60. Low HSPD1 expression was linked to lower overall survival and relapse-free survival rates, with HRs of 1.80 and 1.87, respectively. When TNM classification and HSPD1 expression were considered, CRC patients with low HSPD1 expression and advanced malignancy had a poorer prognosis than those with high HSPD1 expression. Thus, HSPD1/HSP60 can be a useful biomarker for a sophisticated survival prediction in late- and advanced-stage CRC, allowing the design of individualized treatment strategies.

Exploring the Role of Hsp60 in Alzheimer's Disease and Type 2 Diabetes: Suggestion for Common Drug Targeting

Heat shock protein 60 (Hsp60) is a member of the chaperonin family of heat shock proteins (HSPs), primarily found in the mitochondrial matrix. As a molecular chaperone, Hsp60 plays an essential role in mediating protein folding and assembly, and together with the co-chaperon Hsp10, it is thought to maintain protein homeostasis. Recently, it has been found to localize in non-canonical, extra-mitochondrial sites such as cell membranes or extracellular fluids, particularly in pathological conditions. Starting from its biological function, this review aims to provide a comprehensive understanding of the potential involvement of Hsp60 in Alzheimer's disease (AD) and Type II Diabetes Mellitus (T2DM), which are known to share impaired key pathways and molecular dysfunctions. Fragmentary data reported in the literature reveal interesting links between the altered expression level or localization of this chaperonin and several disease conditions. The present work offers an overview of the past and more recent knowledge about Hsp60 and its role in the most important cellular processes to shed light on neuronal Hsp60 as a potential common target for both pathologies. The absence of any effective cure for AD patients makes the identification of a new molecular target a promising path by which to move forward in the development of new drugs and/or repositioning of therapies already used for T2DM.

The boundary of life and death: changes in mitochondrial and cytosolic proteomes associated with programmed cell death of Arabidopsis thaliana suspension culture cells

Introduction

Despite the critical role of programmed cell death (PCD) in plant development and defense responses, its regulation is not fully understood. It has been proposed that mitochondria may be important in the control of the early stages of plant PCD, but the details of this regulation are currently unknown.

Methods

We used Arabidopsis thaliana cell suspension culture, a model system that enables induction and precise monitoring of PCD rates, as well as chemical manipulation of this process to generate a quantitative profile of the alterations in mitochondrial and cytosolic proteomes associated with early stages of plant PCD induced by heat stress. The cells were subjected to PCD-inducing heat levels (10 min, 54°C), with/without the calcium channel inhibitor and PCD blocker LaCl3. The stress treatment was followed by separation of cytosolic and mitochondrial fractions and mass spectrometry-based proteome analysis.

Results

Heat stress induced rapid and extensive changes in protein abundance in both fractions, with release of mitochondrial proteins into the cytosol upon PCD induction. In our system, LaCl3 appeared to act downstream of cell death initiation signal, as it did not affect the release of mitochondrial proteins, but instead partially inhibited changes occurring in the cytosolic fraction, including upregulation of proteins with hydrolytic activity.

Discussion

We characterized changes in protein abundance and localization associated with the early stages of heat stress-induced PCD. Collectively, the generated data provide new insights into the regulation of cell death and survival decisions in plant cells.

The Effects of a Curcumin Derivative and Osimertinib on Fatty Acyl Metabolism and Mitochondrial Functions in HCC827 Cells and Tumors

Drug combination therapy is a key approach in cancer treatments, aiming to improve therapeutic efficacy and overcome drug resistance. Evaluation of intracellular response in cancer cells to drug treatment may disclose the underlying mechanism of drug resistance. In this study, we aimed to investigate the effect of osimertinib, a tyrosine kinase inhibitor (TKI), and a curcumin derivative, 35d, on HCC827 cells and tumors by analyzing alterations in metabolome and related regulations. HCC827 tumor-bearing SCID mice and cultured HCC827 cells were separately examined. The treatment comprised four conditions: vehicle-only, 35d-only, osimertinib-only, and a combination of 35d and osimertinib. The treated tumors/cells were subsequently subjected to metabolomics profiling, fatty acyl analysis, mitochondrial potential measurement, and cell viability assay. Osimertinib induced changes in the ratio of short-chain (SC) to long-chain (LC) fatty acyls, particularly acylcarnitines (ACs), in both tumors and cells. Furthermore, 35d enhanced this effect by further lowering the SC/LC ratio of most ACs. Osimertinib and 35d also exerted detrimental effects on mitochondria through distinct mechanisms. Osimertinib upregulated the expression of carnitine palmitoyltransferase I (CPTI), while 35d induced the expression of heat shock protein 60 (HSP60). The alterations in ACs and CPTI were correlated with mitochondrial dysfunction and inhibited cell growth. Our results suggest that osimertinib and 35d disrupted the fatty acyl metabolism and induced mitochondrial stress in cancer cells. This study provides insights into the potential application of fatty acyl metabolism inhibitors, such as osimertinib or other TKIs, and mitochondrial stress inducers, such as curcumin derivatives, as combination therapy for cancer.

Impact of Non-Invasive Physical Plasma on Heat Shock Protein Functionality in Eukaryotic Cells

Recently, biomedical research has increasingly investigated physical plasma as an innovative therapeutic approach with a number of therapeutic biomedical effects. It is known from radiation and chemotherapy that these applications can lead to the induction and activation of primarily cytoprotective heat shock proteins (HSP). HSP protect cells and tissues from physical, (bio)chemical, and physiological stress and, ultimately, along with other mechanisms, govern resistance and treatment failure. These mechanisms are well known and comparatively well studied in drug therapy. For therapies in the field of physical plasma medicine, however, extremely little data are available to date. In this review article, we provide an overview of the current studies on the interaction of physical plasma with the cellular HSP system.

Alvespimycin Inhibits Heat Shock Protein 90 and Overcomes Imatinib Resistance in Chronic Myeloid Leukemia Cell Lines

Heat shock protein 90 (HSP90) facilitates folding and stability and prevents the degradation of multiple client proteins. One of these HSP90 clients is BCR-ABL, the oncoprotein characteristic of chronic myeloid leukemia (CML) and the target of tyrosine kinase inhibitors, such as imatinib. Alvespimycin is an HSP90 inhibitor with better pharmacokinetic properties and fewer side effects than other similar drugs, but its role in overcoming imatinib resistance is not yet clarified. This work studied the therapeutic potential of alvespimycin in imatinib-sensitive (K562) and imatinib-resistant (K562-RC and K562-RD) CML cell lines. Metabolic activity was determined by the resazurin assay. Cell death, caspase activity, mitochondrial membrane potential, and cell cycle were evaluated by means of flow cytometry. Cell death was also analyzed by optical microscopy. HSPs expression levels were assessed by western blotting. Alvespimycin reduced metabolic activity in a time-, dose-, and cell line-dependent manner. Resistant cells were more sensitive to alvespimycin with an IC₅₀ of 31 nM for K562-RC and 44 nM for K562-RD, compared to 50 nM for K562. This drug induced apoptosis via the mitochondrial pathway. In K562 cells, alvespimycin induced cell cycle arrest in G₀/G₁. As a marker of HSP90 inhibition, a significant increase in HSP70 expression was observed. Our results suggest that alvespimycin might be a new therapeutic approach to CML treatment, even in cases of resistance to imatinib.

Butein promotes ubiquitination-mediated survivin degradation inhibits tumor growth and overcomes chemoresistance

Overexpression of survivin is frequently observed in human malignancies and is associated with poor prognosis. The present study found that survivin is highly expressed in nasopharyngeal carcinoma (NPC) tumor tissues. Depleting survivin with shRNA inhibited cell viability, colony formation, and in vivo tumorigenesis of NPC cells. With a natural product screening, we identified Butein as a potential anti-tumor compound for NPC by reducing survivin protein level. Butein shortened the half-life of survivin and enhanced ubiquitination-mediated degradation. The mechanism study showed that Butein promoted the interaction between survivin and E3 ligase Fbxl7, and the knockdown of Fbxl7 compromised Butein-induced survivin ubiquitination. Butein suppressed the Akt-Wee1-CDK1 signaling and decreased survivin Thr34 phosphorylation, facilitating E3 ligase Fbxl7-mediated survivin ubiquitination and degradation. Moreover, Butein exhibited a strong in vivo anti-tumor activity, as the tumor volume of Butein-treated xenografts was reduced significantly. Butein alone or combined with cisplatin (CDDP) overcame chemoresistance in NPC xenograft tumors. Overall, our data indicate that Butein is a promising anti-tumor agent for NPC treatment.

KBTBD11, encoding a novel PPARγ target gene, is involved in NFATc1 proteolysis by interacting with HSC70 and HSP60

We previously revealed that Kbtbd11 mRNA levels increase during 3T3-L1 differentiation and Kbtbd11 knockdown suppresses whereas its overexpression promotes adipogenesis. However, how Kbtbd11 mRNA is regulated during adipocyte differentiation and how the KBTBD11 protein functions in adipocytes remain elusive. This study aimed to examine the transcriptional regulatory mechanism of Kbtbd11 during adipocyte differentiation, KBTBD11-interacting protein functions, and elucidate the role of KBTBD11 in adipocytes. First, we identified the PPRE consensus sequences in the Kbtbd11 exon 1- and intron 1-containing region and demonstrated that PPARγ acts on this region to regulate Kbtbd11 expression. Next, we purified the KBTBD11 protein complex from 3T3-L1 adipocytes and identified heat shock proteins HSC70 and HSP60 as novel KBTBD11-interacting proteins. HSC70 and HSP60 inhibition increased KBTBD11 protein levels that promoted NFATc1 ubiquitination. These data suggest that HSC70 and HSP60 are involved in KBTBD11 stabilization and are responsible for NFATc1 regulation on the protein level. In summary, this study describes first the protein regulatory mechanism of NFATc1 through the HSC70/HSP60-KBTBD11 interaction that could provide a potential new target for the differentiation and proliferation of various cells, including adipocytes and tumors.

6-Shogaol Exhibits a Promoting Effect with Tax via Binding HSP60 in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) is a prevalent malignant tumor with high morbidity and mortality rates worldwide. Although surgical resection, adjuvant radiotherapy/chemotherapy, and targeted molecular therapy are the cornerstones of NSCLC treatment, NSCLC is associated with high recurrence rates and drug resistance. This study analyzed the potential targets and pathways of 6-Shogaol (6-SH) in NSCLC, showing that 6-SH binds to heat-shock 60 kDa protein (HSP60) in A549 cells, induces cell apoptosis, and arrests the cell cycle possibly by disrupting the mitochondrial function. HSP60 was identified as the target of 6-SH and 6-SH-induced HSP60 degradation which was mediated by the proteasome. The binding of 6-SH with HSP60 altered its stability, inhibited the ERK, Stat3, PI3K, Akt, and mTOR signaling pathways, and Tax acted synergistically with 6-SH, indicating that 6-SH could be developed as a potential therapeutic agent for an NSCLC treatment.

Harm of circadian misalignment to the hearts of the adolescent wistar rats

PURPOSE

The purpose of this study was to observe the harm of circadian misalignment (CM), caused by an inverted photoperiod (IP), on the hearts of the adolescent Wistar rats, and to explore the mechanisms leading to harm.

METHODS

An IP was used to create a CM model. A total of 174 Wistar rats were randomly divided into circadian alignment (CA) and CM groups (87 rats per group). The different activity rhythms of the two groups of rats were adjusted through different light/dark cycles for 90 days. We recorded the rhythmic activity trajectory and sleep time of the rats. After 90 days of modeling, we performed various analyses (i.e., blood pressure, weight, cardiac ultrasound tests, serological tests, cardiac tissue immunofluorescence, immunohistochemistry, transmission electron microscopy on myocardial mitochondria, western blotting, and quantitative polymerase chain reactions).

RESULTS

(1) The IP protocol caused CM in rats. (2) CM rats showed significantly higher blood pressure during the day (resting phase). They also showed significantly higher serum levels of angiotensin II and epinephrine during the day compared to the CA rats. (3) CM caused up-regulation of gene expression of adrenergic receptors α1 (α1-AR) and β1 (β1-AR) and down-regulation of the glucocorticoid receptor (Gr) gene expression in rat hearts. It also caused downregulation of Bmal1 expression. In addition, the changes in Bmal1 and Per2 correlated with the changes in β1-AR and α1-AR. (4) CM had adverse effects on multiple molecular proteins of the heart. (5) CM increased the collagen fibers in the rat heart and increased the destruction of mitochondria. (6) Eventually, CM caused a decrease in the pumping function of the heart and decreased the coronary blood flow rate.

CONCLUSIONS

(1) CM significantly affected the cardiac structure and function in the adolescent rats through a variety of mechanisms. (2) CM can regulate the expression of myocardial clock genes, and it is likely to have an impact on the heart through this pathway.

Perfluorooctanoic acid induces hepatocellular endoplasmic reticulum stress and mitochondrial-mediated apoptosis in vitro via endoplasmic reticulum-mitochondria communication

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant that is widely distributed in the natural environment. Cohort study showed that PFOA-producing workers displayed a significant increase for mortality of liver cancer and liver cirrhosis. However, the underlying mechanism of PFOA-induced hepatotoxicity is far from clear. In this research, cell viability, apoptosis rate, reactive oxygen species, mitochondrial membrane potential (ΔΨm), calcium ion levels, and protein expressions of human liver L02 cells in response to PFOA were determined. Results indicated that a 24 h-treatment with 64 and 256 μM PFOA could remarkably induce mitochondrial-mediated apoptosis via initiating the vicious cycle between endoplasmic reticulum stress and oxidative stress, thereby increasing the level of calcium ion and decreasing the level of ΔΨm, simultaneously elevating the protein expressions of Cyclophilin D (CYPD), Bcl-2 homologous antagonist/killer (Bak), Bcl-2-associated X protein (Bax), Bcl-2-like protein 11 (Bim), cytochrome C (Cyt-C), 78 kDa glucose-regulated protein (GRP78), CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP), and thioredoxin-interacting protein (TXNIP), while inhibiting the protein expression of tumor necrosis factor receptor-associated protein 1 (TRAP1), Lon protease 1 (Lonp1), Pro-caspase-9, B-cell lymphoma-2 (Bcl-2), and Sigma 1-type opioid receptor (Sig-1R) (p < 0.05). To sum up, PFOA-induced hepatocellular endoplasmic reticulum stress and mitochondrial-mediated apoptosis in vitro was regulated by endoplasmic reticulum (ER)-mitochondria communication via mitochondria-associated ER membranes (MAMs).

Mitochondrial chaperones in human health and disease

Molecular chaperones are a family of proteins that maintain cellular protein homeostasis through non-covalent peptide folding and quality control mechanisms. The chaperone proteins found within mitochondria play significant protective roles in mitochondrial biogenesis, quality control, and stress response mechanisms. Defective mitochondrial chaperones have been implicated in aging, neurodegeneration, and cancer. In this review, we focus on the two most prominent mitochondrial chaperones: mtHsp60 and mtHsp70. These proteins demonstrate different cellular localization patterns, interact with different targets, and have different functional activities. We discuss the structure and function of these prominent mitochondrial chaperone proteins and give an update on newly discovered regulatory mechanisms and disease implications.

Deduction of CDC42EP3 suppress development and progression of osteosarcoma

BACKGROUND

Osteosarcoma is a disease with high mortality of malignant tumors in children and adolescents. CDC42 effector protein 3 (CDC42EP3) has been reported to be associated with human cancer cell progression. This study aimed to investigate the biological function and preliminary molecular mechanism of CDC42EP3 in osteosarcoma.

METHODS

CDC42EP3 expression in osteosarcoma was analyzed by immunohistochemical (IHC) staining. Secondly, the biological effects of CDC42EP3 in osteosarcoma cells was determined by loss/gain-of-function assays in vitro and in vivo.

RESULTS

CDC42EP3 expression was higher in osteosarcoma tissue than in noncancerous tissue. The expression of CDC42EP3 was positively correlated with age, pathological stage and grade of patients with osteosarcoma. Furthermore, downregulation of CDC42EP3 suppressed tumor progression by inhibiting proliferation, migration and inducing apoptosis in vivo. Importantly, knockdown of CDC42EP3 reduced the expression of interstitial markers (N-cadherin, Vimentin and Snail) and increased the expression of epithelial markers (E-cadherin). In addition, CDC42EP3 knockdown downregulated PI3K and reduced the phosphorylation levels of AKT and mTOR. The mice xenograft model further confirmed that CDC42EP3 knockdown inhibited osteosarcoma growth in vitro.

CONCLUSIONS

In summary, these findings highlighted the significance of CDC42EP3 in tumor progression, which implicated CDC42EP3 as a promising candidate molecular target for osteosarcoma therapy.

Stress-induced inflammation evoked by immunogenic cell death is blunted by the IRE1α kinase inhibitor KIRA6 through HSP60 targeting

Mounting evidence indicates that immunogenic therapies engaging the unfolded protein response (UPR) following endoplasmic reticulum (ER) stress favor proficient cancer cell-immune interactions, by stimulating the release of immunomodulatory/proinflammatory factors by stressed or dying cancer cells. UPR-driven transcription of proinflammatory cytokines/chemokines exert beneficial or detrimental effects on tumor growth and antitumor immunity, but the cell-autonomous machinery governing the cancer cell inflammatory output in response to immunogenic therapies remains poorly defined. Here, we profiled the transcriptome of cancer cells responding to immunogenic or weakly immunogenic treatments. Bioinformatics-driven pathway analysis indicated that immunogenic treatments instigated a NF-κB/AP-1-inflammatory stress response, which dissociated from both cell death and UPR. This stress-induced inflammation was specifically abolished by the IRE1α-kinase inhibitor KIRA6. Supernatants from immunogenic chemotherapy and KIRA6 co-treated cancer cells were deprived of proinflammatory/chemoattractant factors and failed to mobilize neutrophils and induce dendritic cell maturation. Furthermore, KIRA6 significantly reduced the in vivo vaccination potential of dying cancer cells responding to immunogenic chemotherapy. Mechanistically, we found that the anti-inflammatory effect of KIRA6 was still effective in IRE1α-deficient cells, indicating a hitherto unknown off-target effector of this IRE1α-kinase inhibitor. Generation of a KIRA6-clickable photoaffinity probe, mass spectrometry, and co-immunoprecipitation analysis identified cytosolic HSP60 as a KIRA6 off-target in the IKK-driven NF-κB pathway. In sum, our study unravels that HSP60 is a KIRA6-inhibitable upstream regulator of the NF-κB/AP-1-inflammatory stress responses evoked by immunogenic treatments. It also urges caution when interpreting the anti-inflammatory action of IRE1α chemical inhibitors.

Manuka honey in combination with 5-Fluorouracil decreases physical parameters of colonspheres enriched with cancer stem-like cells and reduces their resistance to apoptosis

The aim of the present work was to evaluate the in vitro effect of Manuka honey and its combination with 5-Fu, the most common drug used in the treatment of colon cancer, on the morphological and physical parameters of colonspheres enriched with cancer stem-like cells deriving from HCT-116 colon adenocarcinoma cell line and on the apoptosis rate. Manuka honey, alone and more in combination with 5-Fu, reduced the weight, the diameter and mass density of the spheroids and induced apoptosis through the downregulation of many apoptosis inhibitors, including IAPs (Livin, Survivin, XIAP), IGFs (IGF-I, IGF-II and IGF-IR) and HSPs (HSP-27, HSP-60 and HSP-70). These results led to a reduction in the survival ability of cancer stem-like cells, as well as to a chemosensitizing effect of honey towards 5-Fu, considering that apoptosis resistance is one of the main causes of cancer stem-like cells chemoresistance.

Cimicifuga dahurica extract inhibits the proliferation, migration and invasion of breast cancer cells MDA-MB-231 and MCF-7 in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Cimicifuga dahurica (Turcz.) Maxim (C. dahurica) has a long history of treating breast cancer. From the Qing Dynasty to the Tang Dynasty and even earlier, C. dahurica has been documented in the treatment of breast carbuncle (Breast cancer is classified as breast carbuncle in Chinese medicine). In traditional prescriptions such as "Sheng Ge Decoction", "Sheng Ma Powder" and "Breast Carbuncle Pill", as the main medicine, C. dahurica plays an important role. At present, the systematic studies on the in vitro and in vivo effects of Cimicifuga against breast cancer are rare, especially the C. dahurica.

AIM OF THE STUDY

In this article, we evaluated the in vitro activity and in vivo effects of CREE (extract of the root of C. dahurica) against breast cancer, and discussed the possible mechanism of CREE in promoting breast cancer cell apoptosis.

MATERIALS AND METHODS

The main component in the CREE was analyzed by HPLC. The effects of CREE on the proliferation, migration and invasion of human breast cancer cells were evaluated through SRB, colony assay, LDH release, wound healing and transwell assay. The pro-apoptotic effect of CREE was investigated in Hochest33342 and Annexin V-FITC/PI assay. To verify the results of CREE in vivo effects, we applied nude mice subcutaneous xenograft experiments. The possible mechanism of CREE treating breast cancer was investigated through mitochondrial membrane potential and western blot experiments.

RESULTS

CREE contains cycloartane triterpene saponins. CREE can significantly inhibit the proliferation, migration and invasion of human breast cancer MCF-7 and MDA-MB-231 cells in vitro and it can effectively inhibit the growth of MDA-MB-231 cell subcutaneous tumors in vivo. Besides, we also found that CREE up-regulated the expression levels of Bax, caspase-9/3 and cytochrome C, and down-regulated the expression of Bcl-2. Therefore, regulation of the mitochondrial pathway may be one of the mechanisms by which CREE promotes breast cancer cell apoptosis.

CONCLUSIONS

CREE exhibits sufficient anti-breast cancer activity in vivo and in vitro, this study provides persuasive evidence for the further research and development of C. dahurica.

Metabolomic Identification of Anticancer Metabolites of Australian Propolis and Proteomic Elucidation of Its Synergistic Mechanisms with Doxorubicin in the MCF7 Cells

The combination of natural products with standard chemotherapeutic agents offers a promising strategy to enhance the efficacy or reduce the side effects of standard chemotherapy. Doxorubicin (DOX), a standard drug for breast cancer, has several disadvantages, including severe side effects and the development of drug resistance. Recently, we reported the potential bioactive markers of Australian propolis extract (AP-1) and their broad spectrum of pharmacological activities. In the present study, we explored the synergistic interactions between AP-1 and DOX in the MCF7 breast adenocarcinoma cells using different synergy quantitation models. Biochemometric and metabolomics-driven analysis was performed to identify the potential anticancer metabolites in AP-1. The molecular mechanisms of synergy were studied by analysing the apoptotic profile via flow cytometry, apoptotic proteome array and measuring the oxidative status of the MCF7 cells treated with the most synergistic combination. Furthermore, label-free quantification proteomics analysis was performed to decipher the underlying synergistic mechanisms. Five prenylated stilbenes were identified as the key metabolites in the most active AP-1 fraction. Strong synergy was observed when AP-1 was combined with DOX in the ratio of 100:0.29 (w/w) as validated by different synergy quantitation models implemented. AP-1 significantly enhanced the inhibitory effect of DOX against MCF7 cell proliferation in a dose-dependent manner with significant inhibition of the reactive oxygen species (p < 0.0001) compared to DOX alone. AP-1 enabled the reversal of DOX-mediated necrosis to programmed cell death, which may be advantageous to decline DOX-related side effects. AP-1 also significantly enhanced the apoptotic effect of DOX after 24 h of treatment with significant upregulation of catalase, HTRA2/Omi, FADD together with DR5 and DR4 TRAIL-mediated apoptosis (p < 0.05), contributing to the antiproliferative activity of AP-1. Significant upregulation of pro-apoptotic p27, PON2 and catalase with downregulated anti-apoptotic XIAP, HSP60 and HIF-1α, and increased antioxidant proteins (catalase and PON2) may be associated with the improved apoptosis and oxidative status of the synergistic combination-treated MCF7 cells compared to the mono treatments. Shotgun proteomics identified 21 significantly dysregulated proteins in the synergistic combination-treated cells versus the mono treatments. These proteins were involved in the TP53/ATM-regulated non-homologous end-joining pathway and double-strand breaks repairs, recruiting the overexpressed BRCA1 and suppressed RIF1 encoded proteins. The overexpression of UPF2 was noticed in the synergistic combination treatment, which could assist in overcoming doxorubicin resistance-associated long non-coding RNA and metastasis of the MCF7 cells. In conclusion, we identified the significant synergy and highlighted the key molecular pathways in the interaction between AP-1 and DOX in the MCF7 cells together with the AP-1 anticancer metabolites. Further in vivo and clinical studies are warranted on this synergistic combination.

HSPA4 Knockdown Retarded Progression and Development of Colorectal Cancer

Purpose

Colorectal cancer (CRC) is a common malignancy associated with high morbidity and mortality. Heat shock 70 kDa protein 4 (HSPA4) has been shown to exert regulatory roles during tumor progression in different cancer types. Here, we investigated the expression and cellular functions of HSPA4 in CRC.

Materials and Methods

Expression of HSPA4 in CRC tissues and paracancerous tissues was analyzed by RT-qPCR and immunohistochemistry IHC staining. The functional roles of HSPA4 were explored using shRNA-mediated knockdown in HCT116 and RKO CRC cell lines, both in vitro and in tumor xenograft studies.

Results

HSPA4 expression was significantly increased at the RNA and protein levels in CRC tissues compared with noncancerous tissues. Moreover, HSPA4 expression was positively associated with tumor stage and its high expression of HSPA4 indicated poor patient prognosis. In vitro studies established that HSPA4 knockdown inhibited proliferation and migration, causing arrest in the G2-phase of the cell cycle along with increased levels of apoptosis. This phenotype was recapitulated in vivo where HSPA4 knockdown suppressed xenograft growth. Mechanistic investigations showed silencing of HSPA4 reduced activation of the PI3K, Akt signaling axis while also downregulating the cell cycle progression markers, CCND1 and CDK6. Similarly, there was altered expression of apoptosis-related proteins consistent with the increase in apoptosis.

Conclusion

Our findings demonstrate clinical significance for HSPA4 in CRC, further showing that HSPA4 contributes to CRC tumorigenesis through effects on proliferation, migration and survival. Thus, HSPA4 represents a novel prognostic indicator as well as a promising therapeutic target in CRC.

DPP3/CDK1 contributes to the progression of colorectal cancer through regulating cell proliferation, cell apoptosis, and cell migration

At present, colorectal cancer (CRC) has become a serious threat to human health in the world. Dipeptidyl peptidase 3 (DPP3) is a zinc-dependent hydrolase that may be involved in several physiological processes. However, whether DPP3 affects the development and progression of CRC remains a mystery. This study is the first to demonstrate the role of DPP3 in CRC. Firstly, the results of immunohistochemistry analysis showed the upregulation of DPP3 in CRC tissues compared with normal tissues, which is statistically analyzed to be positively correlated with lymphatic metastasis, pathological stage, positive number of lymph nodes. Moreover, the high expression of DPP3 predicts poor prognosis in CRC patients. In addition, the results of cell dysfunction experiments clarified that the downregulation of DPP3 significantly inhibited cell proliferation, colony formation, cell migration, and promoted apoptosis in vitro. DPP3 depletion could induce cell apoptosis by upregulating the expression of BID, BIM, Caspase3, Caspase8, HSP60, p21, p27, p53, and SMAC. In addition, downregulation of DPP3 can reduce tumorigenicity of CRC cells in vivo. Furthermore, CDK1 is determined to be a downstream target of DPP3-mediated regulation of CRC by RNA-seq, qPCR, and WB. The interaction between DPP3 and CDK1 shows mutual regulation. Specifically, downregulation of DPP3 can accentuate the effects of CDK1 knockdown on the function of CRC cells. Overexpression of CDK1 alleviates the inhibitory effects of DPP3 knockdown in CRC cells. In summary, DPP3 has oncogene-like functions in the development and progression of CRC by targeting CDK1, which may be an effective molecular target for the prognosis and treatment of CRC.

Exploiting the HSP60/10 chaperonin system as a chemotherapeutic target for colorectal cancer

Over the past few decades, an increasing variety of molecular chaperones have been investigated for their role in tumorigenesis and as potential chemotherapeutic targets; however, the 60 kDa Heat Shock Protein (HSP60), along with its HSP10 co-chaperone, have received little attention in this regard. In the present study, we investigated two series of our previously developed inhibitors of the bacterial homolog of HSP60/10, called GroEL/ES, for their selective cytotoxicity to cancerous over non-cancerous colorectal cells. We further developed a third "hybrid" series of analogs to identify new candidates with superior properties than the two parent scaffolds. Using a series of well-established HSP60/10 biochemical screens and cell-viability assays, we identified 24 inhibitors (14%) that exhibited > 3-fold selectivity for targeting colorectal cancer over non-cancerous cells. Notably, cell viability EC₅₀ results correlated with the relative expression of HSP60 in the mitochondria, suggesting a potential for this HSP60-targeting chemotherapeutic strategy as emerging evidence indicates that HSP60 is up-regulated in colorectal cancer tumors. Further examination of five lead candidates indicated their ability to inhibit the clonogenicity and migration of colorectal cancer cells. These promising results are the most thorough analysis and first reported instance of HSP60/10 inhibitors being able to selectively target colorectal cancer cells and highlight the potential of the HSP60/10 chaperonin system as a viable chemotherapeutic target.

JNK pathway and heat shock response mediate the survival of C26 colon carcinoma bearing mice fed with the mushroom Pleurotus eryngii var. eryngii without affecting tumor growth or cachexia

In the last few years, there has been emerging interest in developing treatments against human diseases using natural bioactive content. Here, the powder of the edible mushroom Pleurotus eryngii var. eryngii was mixed with the normal diet of mice bearing C26 colon carcinoma. Interestingly, it was evidenced by a significant increase in the survival rate of C26 tumor-bearing mice accompanied by a significant increase in Hsp90 and Hsp27 protein levels in the tumors. These data were paralleled by a decrease in Hsp60 levels. The mushroom introduced in the diet induced the inhibition of the transcription of the pro-inflammatory cytokines IL-6 and IL-1 exerting an anti-inflammatory action. The effects of the mushroom were mediated by the activation of c-Jun NH₂-terminal kinases as a result of metabolic stress induced by the micronutrients introduced in the diet. In the tumors of C26 bearing mice fed with Pleurotus eryngii there was also a decreased expression of the mitotic regulator survivin and the anti-apoptotic factor Bcl-xL as well as an increase in the expression levels of Atg7, a protein that drives autophagy. In our hypothesis the interplay of these molecules favored the survival of the mice fed with the mushroom. These data are promising for the introduction of Pleurotus eryngii as a dietary supplement or as an adjuvant in anti-cancer therapy.

Tiliacora racemosa leaves induce oxidative stress mediated DNA damage leading to G2/M phase arrest and apoptosis in cervical cancer cells SiHa

ETHNOPHARMACOLOGICAL RELEVANCE

The Menispermaceae plant Tiliacora racemosa is immensely popular in Indian traditional Ayurvedic medicine as "Krishnavetra" for its remarkable anti-cancerous property, and is commonly used by tribal population for the treatment of skin infections, snake bites and filariasis.

AIM OF THE STUDY

This present study intends to identify the modus operandi behind the cytotoxic activity of Tiliacora racemosa leaves in cervical cancer cells SiHa. Focus has been instilled in the ability of the plant extract to target multiple signaling pathways leading to cell cycle arrest and cell death in SiHa cells, followed by a pharmacological characterization to identify the bioactive principle.

MATERIALS AND METHODS

T. racemosa leaves extracted in methanol, ethyl acetate, hexane and aqueous solvent were screened for cytotoxicity in HeLa, SiHa, C33A (cervical cancer cells) and HEK cells by MTT assay. SiHa cells were treated with the most potent extract (TRM). Cellular morphology, clonogenic and wound healing potential, presence of intracellular ROS and NO, lipid peroxidation, activity of cellular antioxidants (SOD, CAT, GSH), DNA damage detection by comet assay and localisation of γ-H2AX foci, intracellular expression of PARP-1, Bax/Bcl2 and caspase-3, loss in mitochondrial membrane potential by JC1 (flow cytometry) and Rh123 (microscopy), cell cycle analysis, Annexin-FITC assay, AO/EtBr microscopy and apoptotic proteome profiling were undertaken in the treated cells. All the related proteins were studied by immunoblots. Effect of NAC (ROS-scavenger) on cell viability, DNA damage and apoptosis were studied. Phytochemical characterization of all TR extracts was followed by LC-MS analysis of TRM and isolated alkaloid of TR was assessed for cytotoxicity.

RESULTS

The methanol extract of T. racemosa (TRM) rich in bisbenzylisoquinoline and other alkaloids impeded the proliferation of cervical cancer cells SiHa in vitro through disruption of cellular redox homeostasis caused by increase in cellular ROS and NO with concomitant decrease in the cellular antioxidants. Double-stranded DNA damage was noted from γH2AX foci accumulation and Parp-1 activation leading to ATM-Chk2-p53 pathway arresting the cells at G2/M-phase through cyclin B1 inhibition. The mitochondrial membrane potential was also disturbed leading to caspase-3 dependent apoptotic induction by both extrinsic and intrinsic pathway. Immunoblots show TRM also inhibited PI3K/Akt and NFκB pathway. NAC pre-treatment rescued the cell viability proving DNA damage and apoptosis to be direct consequences of ROS overproduction. Lastly, the therapeutic potential of T. racemosa is was hypothesized to be possibly derived from its alkaloid content.

CONCLUSION

This study proves the age old ethnnopharmacological anticancer role of T. racemosa. The leaf extracts inhibited the anomalous proliferation of SiHa cells by virtue of G2/M-phase cell cycle arrest and apoptotic cell death. Oxidative stress mediated double stranded DNA damage paved the way towards apoptotic cell death through multiple routes, including PI3K/Akt/NFκB pathway. The abundant alkaloid content of T. racemosa was denoted as the probable responsible cytotoxic principle.

Prognostic and Functional Significant of Heat Shock Proteins (HSPs) in Breast Cancer Unveiled by Multi-Omics Approaches

Simple Summary

In this study, we investigated the expression pattern and prognostic significance of the heat shock proteins (HSPs) family members in breast cancer (BC) by using several bioinformatics tools and proteomics investigations. Our results demonstrated that, collectively, HSPs were deregulated in BC, acting as both oncogene and onco-suppressor genes. In particular, two different HSP-clusters were significantly associated with a poor or good prognosis. Interestingly, the HSPs deregulation impacted gene expression and miRNAs regulation that, in turn, affected important biological pathways involved in cell cycle, DNA replication, and receptors-mediated signaling. Finally, the proteomic identification of several HSPs members and isoforms revealed much more complexity of HSPs roles in BC and showed that their expression is quite variable among patients. In conclusion, we elaborated two panels of HSPs that could be further explored as potential biomarkers for BC progression and prognosis.

Abstract

Heat shock proteins (HSPs) are a well-characterized molecular chaperones protein family, classified into six major families, according to their molecular size. A wide range of tumors have been shown to express atypical levels of one or more HSPs, suggesting that they could be used as biomarkers. However, the collective role and the possible coordination of HSP members, as well as the prognostic significance and the functional implications of their deregulated expression in breast cancer (BC) are poorly investigated. Here, we used a systematic multi-omics approach to assess the HSPs expression, the prognostic value, and the underlying mechanisms of tumorigenesis in BC. By using data mining, we showed that several HSPs were deregulated in BC and significantly correlated with a poor or good prognosis. Functional network analysis of HSPs co-expressed genes and miRNAs highlighted their regulatory effects on several biological pathways involved in cancer progression. In particular, these pathways concerned cell cycle and DNA replication for the HSPs co-expressed genes, and miRNAs up-regulated in poor prognosis and Epithelial to Mesenchymal Transition (ETM), as well as receptors-mediated signaling for the HSPs co-expressed genes up-regulated in good prognosis. Furthermore, the proteomic expression of HSPs in a large sample-set of breast cancer tissues revealed much more complexity in their roles in BC and showed that their expression is quite variable among patients and confined into different cellular compartments. In conclusion, integrative analysis of multi-omics data revealed the distinct impact of several HSPs members in BC progression and indicate that collectively they could be useful as biomarkers and therapeutic targets for BC management.

Foeniculum vulgare seed extract exerts anti-cancer effects on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. The prognosis of HCC is very poor due to the absence of symptoms and a lack of effective treatments. Studies have shown that various Foeniculum vulgare (fennel) extracts exhibit anti-cancer effects on malignant tumors such as skin cancer and prostate cancer. However, the anti-tumor activity of Foeniculum vulgare and its underlying molecular mechanisms towards HCC are unknown. Here, we provide fundamental evidence to show that the 75% ethanol extract of Foeniculum vulgare seeds (FVE) reduced cell viability, induced apoptosis, and effectively inhibited cell migration in HCC cells in vitro. HCC xenograft studies in nude mice showed that FVE significantly inhibited HCC growth in vivo. Mechanistic analyses showed that FVE reduced survivin protein levels and triggered mitochondrial toxicity, subsequently inducing caspase-3 activation and apoptosis. Survivin inhibition effectively sensitized HCC cells to FVE-induced apoptosis. Moreover, FVE did not induce a decrease in survivin or apoptotic toxicity in normal liver cells. Collectively, in vivo and in vitro results suggest that FVE exerts inhibitory effects in HCC by targeting the oncoprotein survivin, suggesting FVE may be a potential anti-cancer agent that may benefit patients with HCC.

PKCδ mediates mitochondrial ROS generation and oxidation of HSP60 to relieve RKIP inhibition on MAPK pathway for HCC progression

Both protein kinase C (PKC) and reactive oxygen species (ROS) are well-known signaling messengers cross-talking with each other to activate mitogen-activated protein kinases (MAPKs) for progression of hepatocellular carcinoma (HCC). However, the underlying mechanisms are not well elucidated. Especially, whether mitochondrial ROS (mtROS) is involved and how it triggers MAPK signaling are intriguing. In this study, we found mtROS generation and phosphorylation of MAPKs were mediated by PKCδ in HCCs treated with the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Heat shock protein 60 (HSP60), one of the chaperones in mitochondria was the major protein oxidized in TPA-treated HCCs. Moreover, depletion of HSP60 or expression of HSP60 cysteine mutant prevented TPA-induced phosphorylation of MAPKs. To delineate how HSP60 mediated MAPK activation, the role of Raf kinase inhibitor protein (RKIP), a negative regulator of MAPK, was investigated. TPA dissociated RKIP from HSP60 in both mitochondria and cytosol, concurrently with translocation of HSP60 and MAPK from mitochondria to cytosol, which was associated with robust phosphorylation of MAPKs in the cytosol. Moreover, TPA induced opposite phenotypical changes of HCCs, G1 cell cycle arrest, and cell migration, which were prevented by mtROS scavengers and depletion of PKCδ and HSP60. Consistently, TPA increased the migration-related genes, hydrogen peroxide inducible clone5, matrix metalloproteinase-1/3, lamininγ2, and suppressed the cell cycle regulator cyclin E1 (CCNE1) via PKCδ/mtROS/HSP60/MAPK-axis. Finally, c-jun and c-fos were required for TPA-induced expression of the migration-related genes and a novel microRNA, miR-6134, was responsible for TPA-induced suppression of CCNE1. In conclusion, PKCδ cross-talked with mtROS to trigger HSP60 oxidation for release of RKIP to activate MAPK, regulating gene expression for migration, and G1 cell cycle arrest in HCC. Targeted therapy aiming at key players like PKCδ, RKIP, and HSP60 is promising for preventing HCC progression.

Central role of TRAP1 in the ameliorative effect of oleanolic acid on the mitochondrial-mediated and endoplasmic reticulum stress-excitated apoptosis induced by ochratoxin A

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is widely distributed in foodstuffs and feeds, meanwhile oleanolic acid (OA) is ubiquitous in various fruit skins, food materials, and medicinal herbs. Due to that OA has a nephroprotective effect, it has the poteintial to counteract OTA-induced nephrotoxicity by nutritional intervention of OA. Furthermore, tumor necrosis factor receptor-associated protein 1 (TRAP1) acts as the core of endoplasmic reticulum (ER)-mitochondria crosstalk, becoming our focus in the mechanism investigation. In this study, the cell viability, apoptosis rate, and protein expressions of human proximal tubule epithelial-originated kidney-2 (HK-2) cells in response to OTA and/or OA were determined. Results indicated that a 24 h-treatment of 1-5 μM OTA could notably induce mitochondrial-mediated and ER stress (ERS)-excitated apoptosis via inhibiting TRAP1, thereby activating CypD, Bax, Cyt-C, Cleaved Caspase-9, Cleaved Caspase-3, GRP78, p-PERK, p-eIF2α, ATF4, and CHOP and inhibiting Bcl-2 (P < 0.05). Results of the RNA interference of TRAP1 further ascertained its anti-apoptotic function via inhibiting CypD, Bax, GRP78, and CHOP and enhancing Bcl-2 (P < 0.05). The pre-treatment of 2 μM OA for 2 h could remarkably relieve OTA-induced suppression of TRAP1 (P < 0.05). In conclusion, TRAP1 played a central role in the ameliorative effect of OA on the mitochondrial-mediated and ERS-excitated apoptosis induced by OTA.

HSP60 knockdown exerts differential response in endothelial cells and monocyte derived macrophages during atherogenic transformation

Ectopic expression of HSP60 in vascular cells is known to activate auto-immune response that is critical to atherogenic initiation. However, the pathogenic relevance of the aberrant HSP60 upregulation in intracellular signaling pathways associated with atherogenic consequences in vascular cells remains unclear. The aim of the present study was to determine the role of endogenous HSP60 in atherogenic transformation of endothelial cells and macrophages. After generating primary evidence of oxidized low density lipoprotein (OxLDL) induced HSP60 upregulation in human umbilical vein endothelial cells (HUVEC), its physiological relevance in high fat high fructose (HFHF) induced early atherogenic remodelling was investigated in C57BL/6J mice. Prominent HSP60 expression was recorded in tunica intima and media of thoracic aorta that showed hypertrophy, lumen dilation, elastin fragmentation and collagen deposition. Further, HSP60 overexpression was found to be prerequisite for its surface localization and secretion in HUVEC. eNOS downregulation and MCP-1, VCAM-1 and ICAM-1 upregulation with subsequent macrophage accumulation provided compelling evidences on HFHF induced endothelial dysfunction and activation that were also observed in OxLDL treated- and HSP60 overexpressing-HUVEC. OxLDL induced concomitant reduction in NO production and monocyte adhesion were prevented by HSP60 knockdown, implying towards HSP60 mediated possible regulation of the said genes. OxLDL induced HSP60 upregulation and secretion was also recorded in THP-1 derived macrophages (TDMs). HSP60 knockdown in TDMs accounted for higher OxLDL accumulation that correlated with altered scavenger receptors (SR-A1, CD36 and SR-B1) expression further culminating in M1 polarization. Collectively, the results highlight HSP60 upregulation as a critical vascular alteration that exerts differential regulatory role in atherogenic transformation of endothelial cells and macrophages.

HSP60 participates in the anti-glioma effects of curcumin

The chaperone protein heat shock protein 60 (HSP60) is considered a tumor promoter in several types of primary human tumors, where it orchestrates a broad range of survival programs. Curcumin (CCM) is well-established to exhibit several anticancer properties with an excellent safety profile. Our previous study showed that CCM suppresses extracellular HSP60 expression, which is typically released by activated microglia, and acts as an inflammatory factor by binding to Toll-like receptor 4 (TLR-4) on the cell membrane. The present study assessed whether CCM exerted its anti-neuroglioma effects on U87 cells via inhibition of HSP60/TLR-4 signaling, similar to that in microglia. The results demonstrated that CCM significantly inhibited the viability and invasive capacity of neuroglioma U87 cells as evidenced by a Cell Counting Kit-8 assay. Western blotting and ELISA results showed that CCM decreased the expression of HSP60 and its transcriptional factor, heat shock factor 1, and reduced HSP60 release. Accordingly, TLR-4, as the target of HSP60, and its downstream signaling proteins myeloid differentiation primary response 88 (MYD88), NF-κB, inducible nitric oxide synthase and cytokines IL-1β and IL-6 were downregulated by CCM. The expression levels of apoptotic factors associated with NF-κB activation, including TNF-α and caspase-3 were increased in U87 cells by CCM treatment, while p53 expression, a tumor suppressor, was shown to be decreased. Based on the results of the present study, CCM may exert its anti-tumor effects in U87 cells by inhibiting the HSP60/TLR-4/MYD88/NF-κB pathway and inducing tumor cell apoptosis. Thus, CCM may be used as a potential therapy for the clinical treatment of neuroglioma.

MiR-302a-3p aggravates myocardial ischemia-reperfusion injury by suppressing mitophagy via targeting FOXO3

OBJECTIVE

This study aimed to investigate whether the protection of miR-302a-3p in myocardial ischemia-reperfusion injury (MIRI) is mediated through the suppression of mitophagy.

METHODS

We constructed a mouse I/R model in vivo by the ligation of left anterior descending coronary artery for 45 min followed by 2 h reperfusion, and an in vitro model by treating mouse cardiomyocytes with hypoxia-reoxygenation (H/R). Knockdown experiments were then performed in vivo and in vitro to determine the effects of miR-302a-3p knockdown on the mitophagy, mitochondrial dysfunction and oxidative stress and apoptosis. The potential targets of miR-302a-3p were further studied by bioinformatics analysis, luciferase assays, quantitative real-time PCR and western blotting.

RESULTS

MiR-302a-3p expression was significantly upregulated in mice subjected to MIRI and in H/R-treated mouse cardiomyocytes. Functional analyses demonstrated that inhibition of miR-302a-3p protected cardiac tissues against I/R-induced apoptosis and mitophagy, mitochondrial damage and mitochondrial oxidative stress. Furthermore, FOXO3 was identified as the direct target of miR-302a-3p. Mechanistically, knockdown of FOXO3 partially reversed the cardioprotective effects of miR-302a-3p inhibitor.

CONCLUSION

Our study suggested that inhibition of miR-302a-3p promoted mitochondrial autophagy and inhibited oxidative stress by targeting FOXO3 to suppress myocardial apoptosis, representing a potential target for MIRI treatment.

Promotion of ubiquitination-dependent survivin destruction contributes to xanthohumol-mediated tumor suppression and overcomes radioresistance in human oral squamous cell carcinoma

Background

Overexpression of survivin plays a crucial role in tumorigenesis and correlates with poor prognosis in human malignancies. Thus, survivin has been proposed as an attractive target for new anti-tumor interventions.

Methods

A natural product library was used for natural compound screening through MTS assay. The expression of survivin in oral squamous cell carcinoma (OSCC) and the inhibitory effect of xanthohumol (XN) on OSCC were examined by anchorage-dependent and -independent growth assays, immunoblot, immunofluorescence, immunohistochemical staining, ubiquitination analysis, co-immunoprecipitation assay, CRISPR-Cas9-based gene knockout, and xenograft experiment.

Results

Survivin is highly expressed in OSCC patient-derived tissues and cell lines. Knockout of survivin reduced the tumorigenic properties of OSCC cells in vitro and in vivo. With a natural compound screening, we identified that xanthohumol inhibited OSCC cells by reducing survivin protein level and activating mitochondrial apoptotic signaling. Xanthohumol inhibited the Akt-Wee1-CDK1 signaling, which in turn decreased survivin phosphorylation on Thr34, and facilitated E3 ligase Fbxl7-mediated survivin ubiquitination and degradation. Xanthohumol alone or in combination with radiation overcame radioresistance in OSCC xenograft tumors.

Conclusion

Our findings indicate that targeting survivin for degradation might a promising strategy for OSCC treatment.