Alternol eliminates excessive ATP production by disturbing Krebs cycle in prostate cancer

Mechanisms associated with cuproptosis and implications for ovarian cancer

Ovarian cancer, a profoundly fatal gynecologic neoplasm, exerts a substantial economic strain on nations globally. The formidable challenge of its frequent relapse necessitates the exploration of novel cytotoxic agents, efficacious antineoplastic medications with minimal adverse effects, and strategies to surmount resistance to primary chemotherapeutic agents. These endeavors aim to supplement extant pharmacological interventions and elucidate molecular mechanisms underlying induced cytotoxicity, distinct from conventional therapeutic modalities. Recent scientific research has unveiled a novel form of cellular demise, known as copper-death, which is contingent upon the intracellular concentration of copper. Diverging from conventional mechanisms of cellular demise, copper-death exhibits a pronounced reliance on mitochondrial respiration, particularly the tricarboxylic acid (TCA) cycle. Tumor cells manifest distinctive metabolic profiles and elevated copper levels in comparison to their normal counterparts. The advent of copper-death presents alluring possibilities for targeted therapeutic interventions within the realm of cancer treatment. Hence, the primary objective of this review is to present an overview of the proteins and intricate mechanisms associated with copper-induced cell death, while providing a comprehensive summary of the knowledge acquired regarding potential therapeutic approaches for ovarian cancer. These findings will serve as valuable references to facilitate the advancement of customized therapeutic interventions for ovarian cancer.

Natural compound Alternol exerts a broad anti-cancer spectrum and a superior therapeutic safety index in vivo

Introduction

Alternol is a natural compound isolated from the fermentation of a mutated fungus. We have demonstrated its potent anti-cancer effect via the accumulation of radical oxygen species (ROS) in prostate cancer cells in vitro and in vivo. In this study, we tested its anti-cancer spectrum in multiple platforms.

Methods

We first tested its anti-cancer spectrum using the National Cancer Institute-60 (NCI-60) screening, a protein quantitation-based assay. CellTiter-Glo screening was utilized for ovarian cancer cell lines. Cell cycle distribution was analyzed using flow cytometry. Xenograft models in nude mice were used to assess anti-cancer effect. Healthy mice were tested for the acuate systemic toxicity.

Results

Our results showed that Alternol exerted a potent anti-cancer effect on 50 (83%) cancer cell lines with a GI50 less than 5 µM and induced a lethal response in 12 (24%) of those 50 responding cell lines at 10 µM concentration. Consistently, Alternol displayed a similar anti-cancer effect on 14 ovarian cancer cell lines in an ATP quantitation-based assay. Most interestingly, Alternol showed an excellent safety profile with a maximum tolerance dose (MTD) at 665 mg/kg bodyweight in mice. Its therapeutic index was calculated as 13.3 based on the effective tumor-suppressing doses from HeLa and PC-3 cell-derived xenograft models.

Conclusion

Taken together, Alternol has a broad anti-cancer spectrum with a safe therapeutic index in vivo.

Natural compound Alternol actives multiple endoplasmic reticulum stress-responding pathways contributing to cell death

Background: Alternol is a small molecular compound isolated from the fermentation of a mutant fungus obtained from Taxus brevifolia bark. Our previous studies showed that Alternol treatment induced reactive oxygen species (ROS)-dependent immunogenic cell death. This study conducted a comprehensive investigation to explore the mechanisms involved in Alternol-induced immunogenic cell death. Methods: Prostate cancer PC-3, C4-2, and 22RV1 were used in this study. Alternol interaction with heat shock proteins (HSP) was determined using CETSA assay. Alternol-regulated ER stress proteins were assessed with Western blot assay. Extracellular adenosine triphosphate (ATP) was measured using ATPlite Luminescence Assay System. Results: Our results showed that Alternol interacted with multiple cellular chaperone proteins and increased their expression levels, including endoplasmic reticulum (ER) chaperone hypoxia up-regulated 1 (HYOU1) and heat shock protein 90 alpha family class B member 1 (HSP90AB1), as well as cytosolic chaperone heat shock protein family A member 8 (HSPA8). These data represented a potential cause of unfolded protein response (UPR) after Alternol treatment. Further investigation revealed that Alternol treatment triggered ROS-dependent (ER) stress responses via R-like ER kinase (PERK), inositol-requiring enzyme 1α (IRE1α). The double-stranded RNA-dependent protein kinase (PKR) but not activating transcription factor 6 (ATF6) cascades, leading to ATF-3/ATF-4 activation, C/EBP-homologous protein (CHOP) overexpression, and X-box binding protein XBP1 splicing induction. In addition, inhibition of these ER stress responses cascades blunted Alternol-induced extracellular adenosine triphosphate (ATP) release, one of the classical hallmarks of immunogenic cell death. Conclusion: Taken together, our data demonstrate that Alternol treatment triggered multiple ER stress cascades, leading to immunogenic cell death.

Copper homeostasis and copper-induced cell death： Novel targeting for intervention in the pathogenesis of vascular aging

Copper-induced cell death, also known as cuproptosis, is distinct from other types of cell death such as apoptosis, necrosis, and ferroptosis. It can trigger the accumulation of lethal reactive oxygen species, leading to the onset and progression of aging. The significant increases in copper ion levels in the aging populations confirm a close relationship between copper homeostasis and vascular aging. On the other hand, vascular aging is also closely related to the occurrence of various cardiovascular diseases throughout the aging process. However, the specific causes of vascular aging are not clear, and different living environments and stress patterns can lead to individualized vascular aging. By exploring the correlations between copper-induced cell death and vascular aging, we can gain a novel perspective on the pathogenesis of vascular aging and enhance the prognosis of atherosclerosis. This article aims to provide a comprehensive review of the impacts of copper homeostasis on vascular aging, including their effects on endothelial cells, smooth muscle cells, oxidative stress, ferroptosis, intestinal flora, and other related factors. Furthermore, we intend to discuss potential strategies involving cuproptosis and provide new insights for copper-related vascular aging.

Progress in the research of cuproptosis and possible targets for cancer therapy

Developing novel cancer therapies that exploit programmed cell death pathways holds promise for advancing cancer treatment. According to a recently published study in Science, copper death (cuproptosis) occurs when intracellular copper is overloaded, triggering aggregation of lipidated mitochondrial proteins and Fe-S cluster proteins. This intriguing phenomenon is triggered by the instability of copper ions. Understanding the molecular mechanisms behind cuproptosis and its associated genes, as identified by Tsvetkov, including ferredoxin 1, lipoic acid synthase, lipoyltransferase 1, dihydrolipid amide dehydrogenase, dihydrolipoamide transacetylase, pyruvate dehydrogenase α1, pyruvate dehydrogenase β, metallothionein, glutaminase, and cyclin-dependent kinase inhibitor 2A, may open new avenues for cancer therapy. Here, we provide a new understanding of the role of copper death and related genes in cancer.

Unraveling the Peculiar Features of Mitochondrial Metabolism and Dynamics in Prostate Cancer

Prostate cancer (PCa) is the second leading cause of cancer deaths among men in Western countries. Mitochondria, the "powerhouse" of cells, undergo distinctive metabolic and structural dynamics in different types of cancer. PCa cells experience peculiar metabolic changes during their progression from normal epithelial cells to early-stage and, progressively, to late-stage cancer cells. Specifically, healthy cells display a truncated tricarboxylic acid (TCA) cycle and inefficient oxidative phosphorylation (OXPHOS) due to the high accumulation of zinc that impairs the activity of m-aconitase, the enzyme of the TCA cycle responsible for the oxidation of citrate. During the early phase of cancer development, intracellular zinc levels decrease leading to the reactivation of m-aconitase, TCA cycle and OXPHOS. PCa cells change their metabolic features again when progressing to the late stage of cancer. In particular, the Warburg effect was consistently shown to be the main metabolic feature of late-stage PCa cells. However, accumulating evidence sustains that both the TCA cycle and the OXPHOS pathway are still present and active in these cells. The androgen receptor axis as well as mutations in mitochondrial genes involved in metabolic rewiring were shown to play a key role in PCa cell metabolic reprogramming. Mitochondrial structural dynamics, such as biogenesis, fusion/fission and mitophagy, were also observed in PCa cells. In this review, we focus on the mitochondrial metabolic and structural dynamics occurring in PCa during tumor development and progression; their role as effective molecular targets for novel therapeutic strategies in PCa patients is also discussed.

Roles of cuproptosis-related gene DLAT in various cancers: a bioinformatic analysis and preliminary verification on pro-survival autophagy

Background

Studies have shown that the expressions and working mechanisms of Dihydrolipoamide S-acetyltransferase (DLAT) in different cancers vary. It is necessary to analyze the expressions and regulatory roles of DLAT in tumors systematically.

Methods

Online public-platform literature on the relationships between DLAT expression levels and tumor prognosis, methylation status, genetic alteration, drug sensitivity, and immune infiltration has been reviewed. The literature includes such documents as The Cancer Genome Atlas (TCGA), Human Protein Atlas (HPA), Tumor Immune Estimation Resource 2.0 (TIMER2.0), Gene Expression Profiling Interactive Analysis 2 (GEPIA2) and Receiver Operating Characteristic plotter (ROC plotter). The molecular mechanisms of DLAT were explored with the Gene Set Enrichment Analysis (GSEA). The relationship between down-regulated DLAT and autophagy in two liver hepatocellular carcinoma (LIHC) cell lines was confirmed with the western blot method, colony formation assay, and transmission electron microscopy. Tissue microarrays were validated through the immunohistochemical staining of DLAT.

Results

DLAT is upregulated in the LIHC, lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and stomach adenocarcinoma (STAD) tumors but is down-regulated in the head and neck squamous cell carcinoma (HNSC) and kidney renal clear cell carcinoma (KIRC) tumors in comparison with normal tissues. For LIHC patients treated with 5-Fluorouracil and Lenvatinib, the DLAT levels of those in the drug-resistant group are significantly high. In LIHC cells, autophagy will be inhibited, and cell death will be induced when DLAT breaks down. Moreover, there exist positive correlations between DLAT expression levels and infiltration of B cells, DC cells, Tregs, and CD8+ T cells in kidney chromophobe (KICH), breast invasive carcinoma (BRCA), prostate adenocarcinoma (PRAD), LIHC and HPV+ HNSC. In LIHC, markers of Tregs are positively correlated with DLAT. Compared with those of normal tissues, the staining intensity of DLAT and the amount of Tregs marker CD49d in LIHC increase.

Conclusions

Through this study, the expressions of DLAT in various cancer types can be understood comprehensively. It suggests that DLAT may be a prognostic marker for LIHC, LUAD, LUSC, STAD and KIRC. A high DLAT expression in LIHC may promote tumorigenesis by stimulating autophagy and inhibiting anti-tumor immunity.

Idarubicin combats abiraterone and enzalutamide resistance in prostate cells via targeting XPA protein

Although second-generation therapies like abiraterone (ABI) and enzalutamide (ENZ) benefit patients with castration-resistant prostate cancer (CRPC), drug resistance frequently occurs, eventually resulting in therapy failure. In this study, we used two libraries, FDA-approved drug library and CRISP/Cas9 knockout (GeCKO) library to screen for drugs that overcome treatment resistance and to identify the potential drug-resistant genes involved in treatment resistance. Our screening results showed that the DNA-damaging agent idarubicin (IDA) overcame abiraterone and enzalutamide resistance in prostate cancer cells. IDA treatment inhibited the DNA repair protein XPA expression in a transcription-independent manner. Consistently, XPA knockout sensitized prostate cancer cells to abiraterone and enzalutamide treatment. In conclusion, IDA combats abiraterone and enzalutamide resistance by reducing XPA protein level in prostate cancer.

Aberrant gene expression pattern in the glycolysis-cholesterol synthesis axis is linked with immune infiltration and prognosis in prostate cancer: A bioinformatics analysis

Aberrant lipid metabolism is an early event in tumorigenesis and has been found in a variety of tumor types, especially prostate cancer (PCa). Therefore, We hypothesize that PCa can be stratified into metabolic subgroups based on glycolytic and cholesterogenic related genes, and the different subgroups are closely related to the immune microenvironment. Bioinformatics analysis of genomic, transcriptomic, and clinical data from a comprehensive cohort of PCa patients was performed. Datasets included the Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) dataset, GSE70768, our previously published PCa cohort. The unsupervised cluster analysis was employed to stratify PCa samples based on the expression of metabolic-related genes. Four molecular subtypes were identified, named Glycolytic, Cholesterogenic, Mixed, and Quiescent. Each metabolic subtype has specific features. Among the 4 subtypes, the cholesterogenic subtype exhibited better median survival, whereas patients with high expression of glycolytic genes showed the shortest survival. The mitochondrial pyruvate carriers (MPC) 1 exhibited expression difference between PCa metabolic subgroups, but not for MPCs 2. Glycolytic subtypes had lower immune cell scores, while Cholesterogenic subgroups had higher immune cell scores. Our results demonstrated that metabolic classifications based on specific glycolytic and cholesterol-producing pathways provide new biological insights into previously established subtypes and may guide develop personalized therapies for unique tumor metabolism characteristics.

Epigallocatechin gallate triggers apoptosis by suppressing de novo lipogenesis in colorectal carcinoma cells

The de novo lipogenesis (DNL) pathway has been identified as a regulator of cancer progression and aggressiveness. Downregulation of key lipogenesis enzymes has been shown to activate apoptosis in cancerous cells. Epigallocatechin gallate (EGCG) inhibits cancer cell proliferation without causing cytotoxicity in healthy cells. The aim of the present study is to investigate the effects of EGCG on the promotion of apoptosis associated with the DNL pathway inhibition in cancer cells, both in vitro and in vivo. We observed that two colorectal cancer (CRC) cell lines (HCT116 and HT-29) had a higher cytotoxic response to EGCG treatment than hepatocellular carcinoma cells, including HepG2 and HuH-7. EGCG treatment decreased cell viability and increased mitochondrial damage-triggered apoptosis in both HCT116 and HT-29 cancer cells. Additionally, we treated mice transplanted with HCT116 cells with 30 or 50 mg/kg EGCG for 7 days to evaluate the apoptotic effects of EGCN treatment in a xenograft mouse model of cancer. We observed a decrease in intracellular fatty acid levels, which suggested that EGCG-induced apoptosis was associated with a decrease in fatty acid levels in cancer. Suppression of adenosine triphosphate synthesis by EGCG indicated that cell death induction in cancer cells could be mediated by shared components of the DNL and energy metabolism pathways. In addition, EGCG-induced apoptosis suppressed the expression of the phosphorylation protein kinase B and extracellular signal-regulated kinase 1/2 signaling proteins in tumors from xenografted mice. Cytotoxic effects in unaffected organs and tissues of the mouse xenograft model were absent upon EGCG treatment.

Bortezomib potentiates antitumor activity of mitoxantrone through dampening Wnt/β-catenin signal pathway in prostate cancer cells

BACKGROUND

Bortezomib (BZM), alone or in combination with other chemotherapies, has displayed strong anticancer effects in several cancers. The efficacy of the combination of BZM and mitoxantrone (MTX) in treating prostate cancer remains unknown.

METHODS

Anticancer effects of combination of BZM and MTX were determined by apoptosis and proliferation assay in vivo and in vitro. Expression of β-Catenin and its target genes were characterized by western blot and Real-time PCR.

RESULTS

BZM significantly enhanced MTX-induced antiproliferation in vivo and in vitro. Mice administered a combination of BZM and MTX displayed attenuated tumor growth and prolonged survival. BZM significantly attenuated MTX-induced apoptosis. Moreover, the combination of BZM and MTX contributed to inhibition of the Wnt/β-Catenin signaling pathway compared to monotherapy.

CONCLUSIONS

This study demonstrates that BZM enhances MTX-induced anti-tumor effects by inhibiting the Wnt/β-Catenin signaling pathway in prostate cancer cells.

The therapeutic potential of mitochondrial toxins

When screening active compounds by phenotypic assays, we often encounter mitochondrial toxins, which are compounds that can affect mitochondrial functions. In normal cells, these toxins may have relatively low toxicity but can nonetheless show measurable effects even at low concentrations. On the other hand, in animals, mitochondrial toxins can exert severe toxicity. Mitochondrial toxins that act as inhibitors of respiratory chain complexes in oxidative phosphorylation (OXPHOS) are typically avoided during drug discovery efforts, as such compounds can directly promote lethal inhibition of pulmonary respiration. However, mitochondrial toxins could in fact have beneficial therapeutic effects. Anti-cancer strategies that target mitochondrial functions, particularly OXPHOS, have received increasing attention in recent years. In this review article we examine the significance of OXPHOS inhibitors as anti-cancer drug candidates and discuss compounds having microbial origins.

Molecular Basis of Prostate Cancer and Natural Products as Potential Chemotherapeutic and Chemopreventive Agents

Prostate cancer is the second most common malignant cancer in males. It involves a complex process driven by diverse molecular pathways that closely related to the survival, apoptosis, metabolic and metastatic characteristics of aggressive cancer. Prostate cancer can be categorized into androgen dependent prostate cancer and castration-resistant prostate cancer and cure remains elusive due to the developed resistance of the disease. Natural compounds represent an extraordinary resource of structural scaffolds with high diversity that can offer promising chemical agents for making prostate cancer less devastating and curable. Herein, those natural compounds of different origins and structures with potential cytotoxicity and/or in vivo anti-tumor activities against prostate cancer are critically reviewed and summarized according to the cellular signaling pathways they interfere. Moreover, the anti-prostate cancer efficacy of many nutrients, medicinal plant extracts and Chinese medical formulations were presented, and the future prospects for the application of these compounds and extracts were discussed. Although the failure of conventional chemotherapy as well as involved serious side effects makes natural products ideal candidates for the treatment of prostate cancer, more investigations of preclinical and even clinical studies are necessary to make use of these medical substances reasonably. Therefore, the elucidation of structure-activity relationship and precise mechanism of action, identification of novel potential molecular targets, and optimization of drug combination are essential in natural medicine research and development.

Alternol triggers immunogenic cell death via reactive oxygen species generation

Alternol is a naturally occurring compound that exerts antitumor activity in several cancers. However, whether Alternol induces antitumor immune response remains unknown. In this study, we investigated whether Alternol induced immunogenic cell death (ICD) in prostate cancer cells. Alternol triggered ICD in prostate cancer cells, as evidenced by the release of damage-associated molecular patterns (DAMPs) (i.e., calreticulin, CALR; high mobility group protein B1, HMGB1; and adenosine triphosphate, ATP) and pro-inflammatory cytokine (i.e., interleukin [IL]-1α, IL-1β, IL-6, and IL-8) expression. Alternol facilitated tumor-associated antigen uptake and cross-presentation, CD8 + T-cell priming, and T-cell infiltration in tumor-draining lymph nodes (LNs) and tumors. The presence of Alternol fostered antitumor immune response in vivo, resulting in delayed tumor growth and prolonged survival. Moreover, inhibition of reactive oxygen species (ROS) generation blocked Alternol-induced upregulation of pre-inflammation cytokines, endoplasmic reticulum (ER) stress, and consequent antitumor immune response. Overall, our data indicate that Alternol triggers ICD in prostate cancer cells, which is mediated by ROS generation.

A Prognostic Model for Brain Glioma Patients Based on 9 Signature Glycolytic Genes

Objective

To screen glycolytic genes linked to the glioma prognosis and construct the prognostic model.

Methods

The relevant data of glioma were downloaded from TCGA and GTEx databases. GSEA of glycolysis-related pathways was carried out, and enriched differential genes were extracted. Screening out prognostic-related genes with conspicuous significance and construction of the prognostic model were conducted by multivariate Cox regression analysis and Lasso regression analysis. The model was evaluated, and cBioPortal was used to analyze the mutation of the model gene. The expression of the model gene in tumor and normal colon tissue was analyzed. The model was used to evaluate the prognosis of patients in different groups to verify the applicability of the model.

Results

339 differentially glycolytic-related genes were enriched in REACTOME_GLYCOLYSIS, GLYCOLYTIC_PROCESS, HALLMARK_GLYCOLYSIS, and other pathways. We obtained 9 key prognostic genes and constructed the prognostic evaluation model. The 3-year AUC values of the ROC curve display model are greater than 0.75, which indicates that the accuracy of the model is good. The relation of age and risk score to prognosis is shown by univariate and multivariate Cox analysis. The expression of SRD5A3, MDH2, and B3GAT3 genes was significantly upregulated in the tumor tissues, while the HDAC4 and G6PC2 genes were downregulated. The mutation rate of MDH2 and HDAC4 genes was the highest. This model could effectively distinguish the risk of poor prognosis of patients in any age stage.

Conclusion

The prognostic assessment models based on glycolysis-related nine-gene signature could accurately predict the prognosis of patients with GBM.

Signaling, metabolism, and cancer: An important relationship for therapeutic intervention

In cancerous cells, significant changes occur in the activity of signaling pathways affecting a wide range of cellular activities ranging from growth and proliferation to apoptosis, invasiveness, and metastasis. Extensive changes also happen with respect to the metabolism of a cancerous cell encompassing a wide range of functions that include: nutrient acquisition, biosynthesis of macromolecules, and energy generation. These changes are important and some therapeutic approaches for treating cancers have focused on targeting the metabolism of cancerous cells. Oncogenes and tumor suppressor genes have a significant effect on the metabolism of cells. There appears to be a close interaction between metabolism and the signaling pathways in a cancerous cell, in which the interaction provides the metabolic needs of a cancerous cell for uncontrolled proliferation, resistance to apoptosis, and metastasis. In this review, we have reviewed the latest findings in this regard and briefly review the most recent research findings regarding targeting the metabolism of cancer cells as a therapeutic approach for treatment of cancer.

Natural Products Targeting the Mitochondria in Cancers

There are abundant sources of anticancer drugs in nature that have a broad prospect in anticancer drug discovery. Natural compounds, with biological activities extracted from plants and marine and microbial metabolites, have significant antitumor effects, but their mechanisms are various. In addition to providing energy to cells, mitochondria are involved in processes, such as cell differentiation, cell signaling, and cell apoptosis, and they have the ability to regulate cell growth and cell cycle. Summing up recent data on how natural products regulate mitochondria is valuable for the development of anticancer drugs. This review focuses on natural products that have shown antitumor effects via regulating mitochondria. The search was done in PubMed, Web of Science, and Google Scholar databases, over a 5-year period, between 2015 and 2020, with a keyword search that focused on natural products, natural compounds, phytomedicine, Chinese medicine, antitumor, and mitochondria. Many natural products have been studied to have antitumor effects on different cells and can be further processed into useful drugs to treat cancer. In the process of searching for valuable new drugs, natural products such as terpenoids, flavonoids, saponins, alkaloids, coumarins, and quinones cover the broad space.

Mechanisms of enzalutamide resistance in castration-resistant prostate cancer and therapeutic strategies to overcome it

Prostate cancer is the second most common malignancy in men and androgen deprivation therapy is the first-line therapy. However, most cases will eventually develop castration-resistant prostate cancer after androgen deprivation therapy treatment. Enzalutamide is a second-generation androgen receptor antagonist approved by the Food and Drug Administration to treat patients with castration-resistant prostate cancer. Unfortunately, patients receiving enzalutamide treatment will ultimately develop resistance via various complicated mechanisms. This review examines the emerging information on these resistance mechanisms, including androgen receptor-related signalling pathways, glucocorticoid receptor-related pathways and metabolic effects. Notably, lineage plasticity and phenotype switching, gene polymorphisms and the relationship between microRNAs and drug resistance are addressed. Furthermore, potential therapeutic strategies for enzalutamide-resistant castration-resistant prostate cancer treatment are suggested, which can help discover more effective and specific regimens to overcome enzalutamide resistance.

Metabolic regulation of prostate cancer heterogeneity and plasticity

Metabolic reprogramming is one of the main hallmarks of cancer cells. It refers to the metabolic adaptations of tumor cells in response to nutrient deficiency, microenvironmental insults, and anti-cancer therapies. Metabolic transformation during tumor development plays a critical role in the continued tumor growth and progression and is driven by a complex interplay between the tumor mutational landscape, epigenetic modifications, and microenvironmental influences. Understanding the tumor metabolic vulnerabilities might open novel diagnostic and therapeutic approaches with the potential to improve the efficacy of current tumor treatments. Prostate cancer is a highly heterogeneous disease harboring different mutations and tumor cell phenotypes. While the increase of intra-tumor genetic and epigenetic heterogeneity is associated with tumor progression, less is known about metabolic regulation of prostate cancer cell heterogeneity and plasticity. This review summarizes the central metabolic adaptations in prostate tumors, state-of-the-art technologies for metabolic analysis, and the perspectives for metabolic targeting and diagnostic implications.

Mitoxantrone triggers immunogenic prostate cancer cell death via p53-dependent PERK expression

BACKGROUND

Mitoxantrone (MTX) is a synthetic compound used as a second line chemotherapeutic drug for prostate cancer. It has been reported to trigger immunogenic cell death (ICD) in animal model studies, but the underlying mechanism is not fully understood yet, especially not in prostate cancer cells.

METHODS

ICD was determined by assessing the release of damage-associated molecular patterns (DAMPs) in the prostate cancer-derived cell lines LNCaP, 22RV1 and PC-3. Short hairpin RNAs (shRNAs) were used to knock down target gene expression. Phagocytosis was assessed using a dual labeling technology in dendric cells co-cultured with cancer cells. The PERK gene promoter was cloned for dual luciferase assays. Chromatin immunoprecipitation (ChIP) was used to determine p53 protein-DNA binding activity. Immunocompetent mice and murine RM-1 prostate cancer cells were used for vaccination experiments.

RESULTS

MTX treatment induced typical characteristics of DAMP release, including increased cell surface exposure of calreticulin (CALR), and extracellular release of ATP and high mobility group box-1 (HMGB1) protein. MTX also enhanced phagocytosis by dendritic cells. Moreover, MTX treatment increased eukaryotic initiation factor 2α (eIF2α) S51 phosphorylation, which was reduced when PERK and GCN2 were silenced using shRNAs. In addition, PERK or GCN2 silencing significantly reduced MTX-induced release of DAMPs in vitro and anti-tumor immunity in vivo. MTX treatment also resulted in dendritic cell activation in mice, which was attenuated when PERK or GCN2 were silenced in cancer cells used for vaccination. Further analysis revealed that PERK and GCN2 expression was enhanced by MTX treatment, of which PERK, but not GCN2, was enhanced via a p53-dependent mechanism.

CONCLUSION

MTX triggers ICD by activating eIF2α via PERK/GCN2 upregulation in prostate cancer cells. MTX-induced PERK expression upregulation depends on the p53 pathway, while that of GCN2 requires further investigation.

Proteasome inhibitors attenuates mitoxantrone-triggered immunogenic cell death in prostate cancer cells

Both mitoxantrone (MTX) and proteasome inhibitors efficiently trigger immunogenic cell death (ICD) in cancer cells. However, whether the combination of MTX and proteasome inhibitors can synergistically enhance ICD remains unknown. In this study, we showed that the proteasome inhibitors bortezomib (BZM) and carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG132) impaired MTX-induced ICD in prostate cancer cells, as measured using ICD biomarkers and dendritic cell activation in vitro. Mice vaccinated with RM-1 mouse prostate cancer cell line treated with BZM or MG132 in combination with MTX showed enhanced tumor growth, and shortened tumor-free, and worse overall survival compared with those treated with MTX alone. In conclusion, we demonstrated that proteasome inhibitors (BZM or MG132) attenuated MTX-induced ICD, suggesting that proteasome activation was required for MTX-induced ICD.

Alternol/Alteronol: Potent Anti-cancer Compounds With Multiple Mechanistic Actions

Alternol and its oxidate isomer Alteronol are small compounds isolated from the fermentation of a mutant fungus obtained from Taxus brevifolia bark. Preclinical studies showed their potent anti-cancer activities, including attenuating cellular survival pathways, altering protein levels of cell cycle regulators, activating xanthine dehydrogenase to cause accumulation of cellular reactive oxygen species and disrupting cell metabolism by disturbing four Krebs cycle enzymes specifically in malignant cells while having no significant effect on benign cells. In cancer cell culture models, Alternol or Alteronol exert their anti-cancer effect by inducing cell cycle arrest and triggering apoptotic cell death. In mice xenograft models, Alternol or Alteronol potently suppresses tumor growth with no obvious toxicity to the host with a wide therapeutic index over 30-fold. In conclusion, Alternol or Alteronol possess a great potential and feasibility to be developed as an effective anti-tumor therapeutic.

Natural compound Alternol as a novel therapeutic for prostate cancer treatment

Alternol is a monomeric compound purified from the fermentation of a microbial strain obtained from the bark of the yew tree. Recent studies have confirmed that it has specific anti-prostate cancer efficacy in vitro and in vivo. In in vitro cell culture experiments Alternol inhibits prostate cancer cell proliferation by causing cell cycle arrest, reduces the expression of Bcl-2 and other pro-survival proteins, increases the level of radical oxygen species by activating xanthine dehydrogenase, blunts mitochondrial aerobic respiration and ATP production, and triggers autophagy flux. However, there is no significant adverse effect on benign prostatic cells. Animal experiments demonstrated that Alternol significantly inhibits the growth of prostate cancer xenografts without obvious adverse effect on normal tissues and organs. Therefore, Alternol is expected to be developed as a new anti-prostate cancer therapy.

Alterations in glycolytic/cholesterogenic gene expression in hepatocellular carcinoma

Metabolic reprogramming is a hallmark of tumors, including hepatocellular carcinoma (HCC). We used data from The Cancer Genome Atlas and the International Cancer Genome Consortium to assess the alterations in glycolytic and cholesterogenic genes in HCC and to determine their association with clinical features in HCC patients. Based on the gene expression profiles from these databases, we established four subtypes of HCC: cholesterogenic, glycolytic, mixed, and quiescent. The prognosis of the cholesterogenic subgroup was poorer than that of the glycolytic group. Tumors in the glycolytic group were more sensitive to chemotherapy. We also explored the relationships between these metabolic subtypes and previously established HCC subgroups. Glycolytic gene expression correlated strongly with poorer prognostic gene expression in the Hoshida classification of HCC. Whole-genome analyses indicated that aberrant amplification of TP53 and MYC in HCC were associated with abnormal anabolic cholesterol metabolism. The mRNA levels of mitochondrial pyruvate carriers 1 and 2 differed among the HCC metabolic subtypes. In a bioinformatics analysis we identified genomic characteristics of tumor metabolism that varied among different cancer types. These findings demonstrate that metabolic subtypes may be valuable prognostic indicators in HCC patients.

Potentially Critical Roles of NDUFB5, TIMMDC1, and VDAC3 in the Progression of Septic Cardiomyopathy Through Integrated Bioinformatics Analysis

Septic cardiomyopathy (SC) is a rare and harmful cardiovascular disease with decreased left ventricular (LV) output and multiple organ failure, which poses a serious threat to human life. Despite the advances in SC, its diagnostic basis and treatment methods are limited, and the specific diagnostic biomarkers and its candidate regulatory targets have not yet been fully established. In this study, the GSE79962 gene expression profile was retrieved, with 20 patients with SC and 11 healthy donors as control. Weighted gene coexpression network analysis (WGCNA) was employed to investigate gene modules that were strongly correlated with clinical phenotypes. Blue module was found to be most significantly related to SC. Moreover, Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on the coexpression genes in blue module and showed that it was associated with metabolic pathways, oxidative phosphorylation, and cardiac muscle contraction. Furthermore, a total of 10 hub genes NDUFB5, TIMMDC1, VDAC3, COQ10A, MRPL16 (mitochondrial ribosomal protein L16), C3orf43, TMEM182, DLAT, NDUFA8, and PDHB (pyruvate dehydrogenase E1 beta subunit) in the blue module were identified at transcriptional level and further validated at translational level in myocardium of an lipopolysaccharide-induced septic cardiac dysfunction mouse model. Overall, the results of quantitative real-time polymerase chain reaction were consistent with most of the microarray analysis results. Intriguingly, we observed that the highest change was NDUFB5, TIMMDC1, and VDAC3. These identified and validated genes provided references that would advance the understanding of molecular mechanisms of SC. Taken together, using WGCNA, the hub genes NDUFB5, TIMMDC1, and VDAC3 might serve as potential biomarkers for diagnosis and/or therapeutic targets for precise treatment of SC in the future.

Characterization of HMGB1/2 Interactome in Prostate Cancer by Yeast Two Hybrid Approach: Potential Pathobiological Implications

High mobility group box B (HMGB) proteins are pivotal in the development of cancer. Although the proteomics of prostate cancer (PCa) cells has been reported, the involvement of HMGB proteins and their interactome in PCa is an unexplored field of considerable interest. We describe herein the results of the first HMGB1/HMGB2 interactome approach to PCa. Libraries constructed from the PCa cell line, PC-3, and from patients’ PCa primary tumor have been screened by the yeast 2-hybrid approach (Y2H) using HMGB1 and HMGB2 baits. Functional significance of this PCa HMGB interactome has been validated through expression and prognosis data available on public databases. Copy number alterations (CNA) affecting these newly described HMGB interactome components are more frequent in the most aggressive forms of PCa: those of neuroendocrine origin or castration-resistant PCa. Concordantly, adenocarcinoma PCa samples showing CNA in these genes are also associated with the worse prognosis. These findings open the way to their potential use as discriminatory biomarkers between high and low risk patients. Gene expression of a selected set of these interactome components has been analyzed by qPCR after HMGB1 and HMGB2 silencing. The data show that HMGB1 and HMGB2 control the expression of several of their interactome partners, which might contribute to the orchestrated action of these proteins in PCa

Xanthine oxidase-mediated oxidative stress promotes cancer cell-specific apoptosis

The natural compound Alternol was shown to induce profound oxidative stress and apoptotic cell death preferentially in cancer cells. In this study, a comprehensive investigation was conducted to understand the mechanism for Alternol-induced ROS accumulation responsible for apoptotic cell death. Our data revealed that Alternol treatment moderately increased mitochondrial superoxide formation rate, but it was significantly lower than the total ROS positive cell population. Pre-treatment with mitochondria-specific anti-oxidant MitoQ, NOX or NOS specific inhibitors had no protective effect on Alternol-induced ROS accumulation and cell death. However, XDH/XO inhibition by specific small chemical inhibitors or gene silencing reduced total ROS levels and protected cells from apoptosis induced by Alternol. Further analysis revealed that Alternol treatment significantly enhanced XDH oxidative activity and induced a strong protein oxidation-related damage in malignant but not benign cells. Interestingly, benign cells exerted a strong spike in anti-oxidant SOD and catalase activities compared to malignant cells after Alternol treatment. Cell-based protein-ligand engagement and in-silicon docking analysis showed that Alternol interacts with XDH protein on the catalytic domain with two amino acid residues away from its substrate binding sites. Taken together, our data demonstrate that Alternol treatment enhances XDH oxidative activity, leading to ROS-dependent apoptotic cell death.