Association of circulating PLA2G7 levels with cancer cachexia and assessment of darapladib as a therapy

Phospholipase PLA2G7 is complementary to GPX4 in mitigating punicic-acid-induced ferroptosis in prostate cancer cells

Ferroptosis is a cell death pathway that can be promoted by peroxidizable polyunsaturated fatty acids in cancer cells. Here, we investigated the mechanisms underlying the toxicity of punicic acid (PunA), an isomer of conjugated linolenic acids (CLnAs) bearing three conjugated double bonds highly prone to peroxidation, on prostate cancer (PCa) cells. PunA induced ferroptosis in PCa cells and triggered massive lipidome remodeling, more strongly in PC3 androgen-negative cells than in androgen-positive cells. The greater sensitivity of androgen-negative cells to PunA was associated with lower expression of glutathione peroxidase 4 (GPX4). We then identified the phospholipase PLA2G7 as a PunA-induced ferroptosis suppressor in PCa cells. Overexpressing PLA2G7 decreased lipid peroxidation levels, suggesting that PLA2G7 hydrolyzes hydroperoxide-containing phospholipids, thus preventing ferroptosis. Importantly, overexpressing both PLA2G7 and GPX4 strongly prevented PunA-induced ferroptosis in androgen-negative PCa cells. This study shows that PLA2G7 acts complementary to GPX4 to protect PCa cells from CLnA-induced ferroptosis.

Virtual reality-empowered deep-learning analysis of brain cells

Automated detection of specific cells in three-dimensional datasets such as whole-brain light-sheet image stacks is challenging. Here, we present DELiVR, a virtual reality-trained deep-learning pipeline for detecting c-Fos+ cells as markers for neuronal activity in cleared mouse brains. Virtual reality annotation substantially accelerated training data generation, enabling DELiVR to outperform state-of-the-art cell-segmenting approaches. Our pipeline is available in a user-friendly Docker container that runs with a standalone Fiji plugin. DELiVR features a comprehensive toolkit for data visualization and can be customized to other cell types of interest, as we did here for microglia somata, using Fiji for dataset-specific training. We applied DELiVR to investigate cancer-related brain activity, unveiling an activation pattern that distinguishes weight-stable cancer from cancers associated with weight loss. Overall, DELiVR is a robust deep-learning tool that does not require advanced coding skills to analyze whole-brain imaging data in health and disease.

Combination of theoretical analysis and experiments: Exploring the role of PLA2G7 in human cancers, including renal cancer

Background

The pivotal role of phospholipase A2 group VII (PLA2G7) has been identified in specific human cancers, such as prostate cancer, diffuse large B cell lymphoma, and melanoma. Given PLA2G7's significant involvement in established tumors, exploring its role in other cancers is highly relevant.

Methods

In this study, we acquired and analyzed data from The Cancer Genome Atlas database, the UCSC XENA website, and other online platforms including Gene Set Cancer Analysis, cBioPortal, Tumor Immune Estimation Resource, and TISIDB to investigate PLA2G7's role in human cancers, including renal cancer. Furthermore, in vitro experiments, including immunofluorescence, western blotting, and CCK-8 assays, were conducted to elucidate PLA2G7's role in renal cancer. Finally, the relationship between PLA2G7 and various drug sensitivity was explored.

Results

Our findings demonstrate that PLA2G7 is highly expressed and may serve as a valuable candidate biomarker in pan-cancer. PLA2G7 exhibits distinct alteration frequencies across human cancers and is correlated with tumor mutation burden, tumor microenvironment, DNA stemness score, RNA stemness score, tumorigenesis, tumor immunity, and microsatellite instability in pan-cancer. Immunofluorescence and western blotting revealed a relative high level of PLA2G7 protein in renal cancer cell lines (ACHN and 786-O), predominantly localized in the cytoplasm. Treatment with a PLA2G7 gene inhibitor (darapladib) significantly decreased the viability of ACHN and 786-O cell lines. Additionally, we observed an association between PLA2G7 mRNA levels and various drug sensitivity.

Conclusions

Our study suggests that PLA2G7 has the potential to serve as a valuable biomarker and therapeutic target for cancer, particularly in the context of renal cancer.

Cancer cachexia: biomarkers and the influence of age

Cancer cachexia (Ccx) is a complex metabolic condition characterized by pronounced muscle and fat wasting, systemic inflammation, weakness and fatigue. Up to 30% of cancer patients succumb directly to Ccx, yet therapies that effectively address this perturbed metabolic state are rare. In recent decades, several characteristics of Ccx have been established in mice and humans, of which we here highlight adipose tissue dysfunction, muscle wasting and systemic inflammation, as they are directly linked to biomarker discovery. To counteract cachexia pathogenesis as early as possible and mitigate its detrimental impact on anti-cancer treatments, identification and validation of clinically endorsed biomarkers assume paramount importance. Ageing was recently shown to affect both the validity of Ccx biomarkers and Ccx development, but the underlying mechanisms are still unknown. Thus, unravelling the intricate interplay between ageing and Ccx can help to counteract Ccx pathogenesis and tailor diagnostic and treatment strategies to individual needs.

Inhibiting PLA2G7 reverses the immunosuppressive function of intratumoral macrophages and augments immunotherapy response in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is an exceptionally immunosuppressive malignancy characterized by limited treatment options and a dismal prognosis. Macrophages constitute the primary and heterogeneous immune cell population within the HCC microenvironment. Our objective is to identify distinct subsets of macrophages implicated in the progression of HCC and their resistance to immunotherapy.

METHODS

Intratumoral macrophage-specific marker genes were identified via single-cell RNA sequencing analyses. The clinical relevance of phospholipase A2 Group VII (PLA2G7), a pivotal enzyme in phospholipid metabolism, was assessed in patients with HCC through immunohistochemistry and immunofluorescence. Flow cytometry and an in vitro co-culture system were used to elucidate the specific role of PLA2G7 in macrophages. Orthotopic and subcutaneous HCC mouse models were employed to evaluate the potential of the PLA2G7 inhibitor in complementing immune checkpoint blockade (ICB) therapy.

RESULTS

Single-cell RNA sequencing analyses disclosed predominant PLA2G7 expression in intratumoral macrophages within the HCC microenvironment. The macrophage-specific PLA2G7 was significantly correlated with poorer prognosis and immunotherapy resistance in patients with HCC. PLA2G7high macrophages represent a highly immunosuppressive subset and impede CD8 T-cell activation. Pharmacological inhibition of PLA2G7 by darapladib improved the therapeutic efficacy of anti-programmed cell death protein 1 antibodies in the HCC mouse models.

CONCLUSIONS

Macrophage-specific PLA2G7 serves as a novel biomarker capable of prognosticating immunotherapy responsiveness and inhibiting PLA2G7 has the potential to enhance the efficacy of ICB therapy for HCC.

Dissecting the tumour immune microenvironment in merkel cell carcinoma based on a machine learning framework

Merkel cell carcinoma (MCC) is a primary cutaneous neoplasm of neuroendocrine carcinoma of the skin, which is characterized by molecular heterogeneity with diverse tumour microenvironment (TME). However, we are still lack knowledge of the cellular states and ecosystems in MCC. Here, we systematically identified and characterized the landscape of cellular states and ecotypes in MCC based on a machine learning framework. We obtained 30 distinct cellular states from 9 immune cell types and investigated the B cell, CD8 T cell, fibroblast, and monocytes/macrophage cellular states in detail. The functional profiling of cellular states were investigated and found the genes highly expressed in cellular states were significantly enriched in immune- and cancer hallmark-related pathways. In addition, four ecotypes were further identified which were with different patient compositions. Transcriptional regulation analysis revealed the critical transcription factors (i.e. E2F1, E2F3 and E2F7), which play important roles in regulating the TME of MCC. In summary, the findings of this study may provide rich knowledge to understand the intrinsic subtypes of MCCs and the pathways involved in distinct subtype oncogenesis, and will further advance the knowledge in developing a specific therapeutic strategy for these MCC subtypes.

Associations of phase angle with platelet-activating factor metabolism and related dietary factors in healthy volunteers

Introduction

Phase angle (PA) is derived from bioelectrical impedance analysis (BIA). It reflects cell membrane function and decreases in disease. It is affected by inflammation, oxidative stress, and diet. Platelet-activating factor (PAF) is a potent inflammatory lipid mediator. Its levels, along with the activity of its metabolic enzymes, including CDP-choline:1-alkyl-2-acetyl-sn-glycerol-cholinephosphotransferase, acetyl-CoA:lyso-PAF-acetyltransferases, and PAF-AH/Lp-PLA2 are also related to dietary factors, such as the dietary antioxidant capacity (DAC). The aim of the study was to estimate whether the PAF metabolic circuit and related dietary factors are associated with PA in healthy volunteers.

Methods

In healthy subjects, PAF, its metabolic enzyme activity, and erythrocyte fatty acids were measured, while desaturases were estimated. Food-frequency questionnaires and recalls were used, and food groups, macronutrient intake, MedDietScore, and DAC were assessed. Lifestyle and biochemical variables were collected. DXA and BIA measurements were performed.

Results

Lp-PLA2 activity was positively associated with PA (rho = 0.651, p < 0.001, total population; rho = 0.780, p < 0.001, women), while PAF levels were negatively associated with PA only in men (partial rho = -0.627, p = 0.012) and inversely related to DAC. Estimated desaturase 6 was inversely associated with PA (rho = -0.404, p = 0.01, total sample). Moreover, the DAC correlated positively with PA (rho = 0.513, p = 0.03, women). All correlations were adjusted for age, body mass index, and sex (if applicable).

Conclusion

PA is associated with PAF levels and Lp-PLA2 activity in a gender-dependent fashion, indicating the involvement of PAF in cell membrane impairment. The relationship of PA with DAC suggests a protective effect of antioxidants on cellular health, considering that antioxidants may inhibit PAF generation.

Investigating the potential mechanism of quercetin against cervical cancer

BACKGROUND

Cervical cancer is emerging as a potential target of increased susceptibility to coronavirus disease-2019 (COVID-19), leading to compromised survival rates. Despite this critical link, efficacious anti-cervical cancer/COVID-19 interventions remain limited. Quercetin, known for its efficacy against both cancer and viral infections, holds promise as a therapeutic agent. This study aims to elucidate quercetin's anti-cervical cancer/COVID-19 mechanisms and potential targets.

METHODS

We initiated our investigation with differential gene expression analysis using cervical cancer transcriptome data from The Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx), focusing on intersections with COVID-19-related genes. Network pharmacology was employed to identify the shared targets between cervical cancer/COVID-19 DEGs and quercetin's targets. Subsequently, Cox proportional hazards analyses were employed to establish a risk score based on these genes. Molecular docking techniques were applied to predict quercetin's therapeutic targets and mechanisms for mitigating cervical cancer and COVID-19.

RESULTS

Our findings unveiled 45 potential quercetin targets with anti-cervical cancer/COVID-19 actions. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses highlighted significant enrichment in immune pathways and COVID-19-related pathways. A refined risk score model, comprising PLA2G7, TNF, TYK2, F2, and NRP1, effectively stratified cervical cancer patients into distinct risk groups. Importantly, molecular docking analyses illuminated quercetin's remarkable binding affinity to the primary protease of the coronavirus.

CONCLUSIONS

In summation, our study suggests that quercetin holds promise as a potential therapeutic agent for mitigating coronavirus function, specifically through its interaction with the primary protease. This research offers novel insights into exploring COVID-19 susceptibility and enhancing survival in cervical cancer patients.

Nutritional Risk and Sarcopenia Features in Patients with Crohn's Disease: Relation to Body Composition, Physical Performance, Nutritional Questionnaires and Biomarkers

Patients with Crohn's disease (CD) face malnutrition risk, which, combined with inflammation, can lead to sarcopenia, associated with a worse prognosis. The purpose of the present study was to assess malnutrition and sarcopenia in patients with CD. Fifty-three patients (26 women) participated (38.1 ± 10.9 years, 79% in remission). Body composition, physical performance, nutritional questionnaires, and biomarkers were performed. Malnutrition was screened with the Mini Nutritional Assessment (MNA) and the Malnutrition Inflammation Risk Tool (MIRT) and was assessed with the Global Leadership Initiative on Malnutrition (GLIM) tool using etiologic along with three different phenotypic criteria: low Body Mass Index (BMI), low Calf Circumference (CC), and low Fat-Free Mass Index (FFMI). To find cases and evaluate sarcopenia, the Sarcopenia Questionnaire (SARC-F) and European Working Group on Sarcopenia2 (EWGSOP2) criteria were used. Malnutrition rates were 11.3% (n = 6), 7.5% (n = 4), and 5.6% (n = 3) based on low FFMI, CC, and BMI, correspondingly. Four (7%) patients had low Hand-Grip Strength (HGS), n = 8 (14.8%) had low Appendicular Lean Mass (ALM), and n = 3 (5.6%) had low gait speed. No-one had sarcopenia. A high albumin and triceps skinfold pattern, identified by principal component analysis, was related to reduced C-Reactive Protein (CRP) levels (B = -0.180, SE = 0.085, p = 0.045). In conclusion, based on the studied anthropometric, nutritional, and functional variables, CD patients were not diagnosed with sarcopenia in the present study. Body composition patterns were related to the inflammatory burden, underlying the interplay of inflammation and malnutrition, even in remission states. Further studies on older populations and during disease exacerbation are necessary to explore the potential link between CD, inflammation, and sarcopenia.

Cachexia: A systemic consequence of progressive, unresolved disease

Cachexia, a systemic wasting condition, is considered a late consequence of diseases, including cancer, organ failure, or infections, and contributes to significant morbidity and mortality. The induction process and mechanistic progression of cachexia are incompletely understood. Refocusing academic efforts away from advanced cachexia to the etiology of cachexia may enable discoveries of new therapeutic approaches. Here, we review drivers, mechanisms, organismal predispositions, evidence for multi-organ interaction, model systems, clinical research, trials, and care provision from early onset to late cachexia. Evidence is emerging that distinct inflammatory, metabolic, and neuro-modulatory drivers can initiate processes that ultimately converge on advanced cachexia.

Promotion of colorectal cancer cell death by ezetimibe via mTOR signaling-dependent mitochondrial dysfunction

Introduction: Colorectal cancer (CRC) is the fourth most common cancer worldwide, with high morbidity and mortality rates. In recent years, high-fat diet has been shown to increase CRC morbidity, highlighting the possibility of the application of hypolipidemic drugs for CRC treatment. In this study, we preliminarily evaluated the effects and mechnisms of ezetimibe against CRC through the blockage of lipid absorption in small intesine. Methods: In this study, CRC cell proliferation, invasion, apoptosis, and autophagy were evaluated using cellular and molecular assays. Fluorescent microscopy, and a flow cytometric assay were used to assess mitochondrial activity in vitro. A subcutaneous xenograft mouse model was used to evaluate the effects of ezetimibe in vivo. Results: We found that ezetimibe inhibited CRC cell proliferation, and migration, and facilitated autophage-associated apoptosis in HCT116 and Caco2 cells. Ezetimibe-induced mitochondrial dysfunction in CRC cells was found to be correlated with mTOR signaling activity. Discussion: Ezetimibe exhibits effects against CRC through the promotion of cancer cell death via mTOR signaling-dependent mitochondrial dysfunction, highlighting its potential value in CRC therapy.

Integrated analysis of Dendrobium nobile extract Dendrobin A against pancreatic ductal adenocarcinoma based on network pharmacology, bioinformatics, and validation experiments

Background: Dendrobium nobile (D. nobile), a traditional Chinese medicine, has received attention as an anti-tumor drug, but its mechanism is still unclear. In this study, we applied network pharmacology, bioinformatics, and in vitro experiments to explore the effect and mechanism of Dendrobin A, the active ingredient of D. nobile, against pancreatic ductal adenocarcinoma (PDAC). Methods: The databases of SwissTargetPrediction and PharmMapper were used to obtain the potential targets of Dendrobin A, and the differentially expressed genes (DEGs) between PDAC and normal pancreatic tissues were obtained from The Cancer Genome Atlas and Genotype-Tissue Expression databases. The protein-protein interaction (PPI) network for Dendrobin A anti-PDAC targets was constructed based on the STRING database. Molecular docking was used to assess Dendrobin A anti-PDAC targets. PLAU, one of the key targets of Dendrobin A anti-PDAC, was immunohistochemically stained in clinical tissue arrays. Finally, in vitro experiments were used to validate the effects of Dendrobin A on PLAU expression and the proliferation, apoptosis, cell cycle, migration, and invasion of PDAC cells. Results: A total of 90 genes for Dendrobin A anti-PDAC were screened, and a PPI network for Dendrobin A anti-PDAC targets was constructed. Notably, a scale-free module with 19 genes in the PPI indicated that the PPI is highly credible. Among these 19 genes, PLAU was positively correlated with the cachexia status while negatively correlated with the overall survival of PDAC patients. Through molecular docking, Dendrobin A was found to bind to PLAU, and the Dendrobin A treatment led to an attenuated PLAU expression in PDAC cells. Based on clinical tissue arrays, PLAU protein was highly expressed in PDAC cells compared to normal controls, and PLAU protein levels were associated with the differentiation and lymph node metastatic status of PDAC. In vitro experiments further showed that Dendrobin A treatment significantly inhibited the proliferation, migration, and invasion, inducing apoptosis and arresting the cell cycle of PDAC cells at the G2/M phase. Conclusion: Dendrobin A, a representative active ingredient of D. nobile, can effectively fight against PDAC by targeting PLAU. Our results provide the foundation for future PDAC treatment based on D. nobile.

Tumor cell anabolism and host tissue catabolism-energetic inefficiency during cancer cachexia

Cancer-associated cachexia (CC) is a pathological condition characterized by sarcopenia, adipose tissue depletion, and progressive weight loss. CC is driven by multiple factors such as anorexia, excessive catabolism, elevated energy expenditure by growing tumor mass, and inflammatory mediators released by cancer cells and surrounding tissues. In addition, endocrine system, systemic metabolism, and central nervous system (CNS) perturbations in combination with cachexia mediators elicit exponential elevation in catabolism and reduced anabolism in skeletal muscle, adipose tissue, and cardiac muscle. At the molecular level, mechanisms of CC include inflammation, reduced protein synthesis, and lipogenesis, elevated proteolysis and lipolysis along with aggravated toxicity and complications of chemotherapy. Furthermore, CC is remarkably associated with intolerance to anti-neoplastic therapy, poor prognosis, and increased mortality with no established standard therapy. In this context, we discuss the spatio-temporal changes occurring in the various stages of CC and highlight the imbalance of host metabolism. We provide how multiple factors such as proteasomal pathways, inflammatory mediators, lipid and protein catabolism, glucocorticoids, and in-depth mechanisms of interplay between inflammatory molecules and CNS can trigger and amplify the cachectic processes. Finally, we highlight current diagnostic approaches and promising therapeutic interventions for CC.

Association of circulating PLA2G7 levels with cancer cachexia and assessment of darapladib as a therapy

BACKGROUND

Cancer cachexia (CCx) is a multifactorial wasting disorder characterized by involuntary loss of body weight that affects many cancer patients and implies a poor prognosis, reducing both tolerance to and efficiency of anticancer therapies. Actual challenges in management of CCx remain in the identification of tumour-derived and host-derived mediators involved in systemic inflammation and tissue wasting and in the discovery of biomarkers that would allow for an earlier and personalized care of cancer patients. The aim of this study was to identify new markers of CCx across different species and tumour entities.

METHODS

Quantitative secretome analysis was performed to identify specific factors characteristic of cachexia-inducing cancer cell lines. To establish the subsequently identified phospholipase PLA2G7 as a marker of CCx, plasma PLA2G7 activity and/or protein levels were measured in well-established mouse models of CCx and in different cohorts of weight-stable and weight-losing cancer patients with different tumour entities. Genetic PLA2G7 knock-down in tumours and pharmacological treatment using the well-studied PLA2G7 inhibitor darapladib were performed to assess its implication in the pathogenesis of CCx in C26 tumour-bearing mice.

RESULTS

High expression and secretion of PLA2G7 were hallmarks of cachexia-inducing cancer cell lines. Circulating PLA2G7 activity was increased in different mouse models of CCx with various tumour entities and was associated with the severity of body wasting. Circulating PLA2G7 levels gradually rose during cachexia development. Genetic PLA2G7 knock-down in C26 tumours only partially reduced plasma PLA2G7 levels, suggesting that the host is also an important contributor. Chronic treatment with darapladib was not sufficient to counteract inflammation and tissue wasting despite a strong inhibition of the circulating PLA2G7 activity. Importantly, PLA2G7 levels were also increased in colorectal and pancreatic cancer patients with CCx.

CONCLUSIONS

Overall, our data show that despite no immediate pathogenic role, at least when targeted as a single entity, PLA2G7 is a consistent marker of CCx in both mice and humans. The early increase in circulating PLA2G7 levels in pre-cachectic mice supports future prospective studies to assess its potential as biomarker for cancer patients.