Autophagy as a modulator of cell death machinery

The interplay between probiotics and host autophagy: mechanisms of action and emerging insights

Autophagy, a lysosome-dependent protein degradation mechanism, is a highly conserved catabolic process seen in all eukaryotes. This cell protection system, which is present in all tissues and functions at a basic level, can be up- or downregulated in response to various stresses. A disruption in the natural route of the autophagy process is frequently followed by an interruption in the inherent operation of the body's cells and organs. Probiotics are live bacteria that protect the host through various mechanisms. One of the processes through which probiotics exert their beneficial effects on various cells and tissues is autophagy. Autophagy can assist in maintaining host homeostasis by stimulating the immune system and affecting numerous physiological and pathological responses. In this review, we particularly focus on autophagy impairments occurring in several human illnesses and investigate how probiotics affect the autophagy process under various circumstances.Abbreviation: AD: Alzheimer disease; AKT: AKT serine/threonine kinase; AMPK: 5'AMP-activated protein kinase; ATG: autophagy related; CCl4: carbon tetrachloride; CFS: cell-free supernatant; CMA: chaperone-mediated autophagy; CRC: colorectal cancer; EPS: L. plantarum H31 exopolysaccharide; HD: Huntington disease; HFD: high-fat diet; HPV: human papillomavirus; IFNG/IFN-γ: interferon gamma; IL6: interleukin 6; LGG: L. rhamnosus GG; LPS: lipopolysaccharide; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; PD: Parkinson disease; Pg3G: pelargonidin-3-O-glucoside; PI3K: phosphoinositide 3-kinase; PolyQ: polyglutamine; ROS: reactive oxygen species; SCFAs: short-chain fatty acids; SLAB51: a novel formulation of lactic acid bacteria and bifidobacteria; Slp: surface layer protein (of acidophilus NCFM); SNCA: synuclein alpha; ULK1: unc-51 like autophagy-activating kinase 1; YB: B. longum subsp. infantis YB0411; YFP: yeast fermentate prebiotic.

Gboxin Induced Apoptosis and Ferroptosis of Cervical Cancer Cells by Promoting Autophagy-Mediated Inhibition of Nrf2 Signaling Under Low-Glucose Conditions

Cervical cancer poses a substantial threat to women's health, underscoring the necessity for effective therapeutic agents with low toxicity that specifically target cancer cells. As cancer progresses, increased glucose consumption causes glucose scarcity in the tumor microenvironment (TME). Consequently, it is imperative to identify pharmacological agents capable of effectively killing cancer cells under conditions of low glucose availability within the TME. Previous studies showed that Gboxin, a small molecule, inhibited glioblastoma (GBM) growth by targeting ATP synthase without harming normal cells. However, its effects and mechanisms in cervical cancer cells in low-glucose environments are not clear. This study indicates that Gboxin notably enhanced autophagy, apoptosis, and ferroptosis in cervical cells under low-glucose conditions without significantly affecting cell survival under normal conditions. Further analysis revealed that Gboxin inhibited the activity of complex V and the production of ATP, concurrently leading to a reduction in mitochondrial membrane potential and the mtDNA copy number under low-glucose culture conditions. Moreover, Gboxin inhibited tumor growth under nutrient deprivation conditions in vivo. A mechanistic analysis revealed that Gboxin activated the AMPK signaling pathway by targeting mitochondrial complex V. Furthermore, increased AMPK activation subsequently promoted autophagy and reduced p62 protein levels. The decreased levels of p62 protein facilitated the degradation of Nrf2 by regulating the p62-Keap1-Nrf2 axis, thereby diminishing the antioxidant capacity of cervical cancer cells, ultimately leading to the induction of apoptosis and ferroptosis. This study provides a better theoretical basis for exploring Gboxin as a potential drug for cervical cancer treatment.

Dysregulation of pancreatic β-cell autophagy and the risk of type 2 diabetes

Macroautophagy/autophagy is an essential degradation process that removes abnormal cellular components, maintains homeostasis within cells, and provides nutrition during starvation. Activated autophagy enhances cell survival during stressful conditions, although overactivation of autophagy triggers induction of autophagic cell death. Therefore, early-onset autophagy promotes cell survival whereas late-onset autophagy provokes programmed cell death, which can prevent disease progression. Moreover, autophagy regulates pancreatic β-cell functions by different mechanisms, although the precise role of autophagy in type 2 diabetes (T2D) is not completely understood. Consequently, this mini-review discusses the protective and harmful roles of autophagy in the pancreatic β cell and in the pathophysiology of T2D.

circCUL3 drives malignant progression of cervical cancer by activating autophagy through sponge miR-223-3p upregulation of ATG7

Circular RNA (circRNA) has emerged as a pivotal regulatory factor in cancer biology, yet its exact role in cervical cancer remains incompletely understood. In this study, we investigated the functional role of circCUL3 in cervical cancer and explored its potential as a therapeutic target. Functional gain and loss experiments were conducted in Hela and Siha cell lines to elucidate the biological functions of circCUL3 in cervical cancer. The results revealed that circCUL3 overexpression significantly enhanced cell viability, migration, and invasion while suppressing apoptosis, while circCUL3 knockout displayed the opposite effects. Mechanistically, we identified hsa-miR-223-3p as a target of circCUL3, with its expression being negatively regulated by circCUL3. Furthermore, we discovered that circCUL3 could sequester miR-223-3p, leading to the upregulation of ATG7 expression, and this was linked to the regulation of autophagy in cervical cancer cells. In vivo validation using a xenograft mouse model further supported our in vitro findings. Notably, we found that chloroquine (CQ), an autophagy inhibitor, restored miR-223-3p expression and counteracted the oncogenic effect of circCUL3 overexpression. In conclusion, circCUL3 potentially contributes to the malignant progression of cervical cancer by acting as a sponge for miR-223-3p, resulting in the upregulation of ATG7 and the activation of autophagy.

Comprehensive analysis of the expression level, prognostic value, and immune infiltration of cuproptosis-related genes in human breast cancer

BACKGROUND

As a novel cell death form, cuproptosis results from copper combining with lipidated proteins in the tricarboxylic acid cycle. To the best of our knowledge no study has yet comprehensively analyzed the relationship between cuproptosis-related genes and breast cancer.

METHODS

The expression, prognostic value, mutations, chemosensitivity, and immune infiltration of cuproptosis-related genes in breast carcinoma patients were analyzed, PPI networks were constructed, and enrichment analyses were performed based on these genes. TIMER, UALCAN, Kaplan-Meier plotter, Human Protein Atlas, cBioPortal, STRING, GeneMANIA, DAVID, and R program v4.0.3 were used to accomplish the analyses above.

RESULTS

Compared to normal breast tissues, FDX1, LIAS, LIPT1, DLD, DLAT, PDHA1, MTF1, and GLS were down-regulated in breast cancer tissues, while CDKN2A was up-regulated. High expression of FDX1, LIAS, DLD, DLAT, MTF1, GLS, and CDKN2A were associated with favorable overall survival. Cuproptosis-related genes showed a high alteration rate (51.3%) in breast cancer, contributing to worse clinical outcomes. The expression levels of FDX1, LIPT1, DLD, DLAT, PDHA1, PDHB, MTF1, GLS, and CDKN2A were associated positively with 1 or more immune cell infiltrations in breast cancer. Patients with high levels of B cell, CD4+ T cell, CD8+ T cell, and dendritic cell infiltration had a higher survival rate at 10 years.

CONCLUSION

This study comprehensively investigated relationships between cuproptosis and breast cancer by bioinformatic analyses. We found that cuproptosis-related genes were generally lowly expressed in breast carcinoma tissue. As the critical gene of cuproptosis, high expression of FDX1 was related to favorable prognoses in breast cancer patients; thus, it might be a potential prognostic marker. Moreover, genes associated with cuproptosis were linked to immune infiltration in breast cancer and this relationship affected the prognosis of breast cancer.

Novel neuroprotective 5,6-dihydropyrido[2',1':2,3]imidazo[4,5-c]quinoline derivatives acting through cholinesterase inhibition and CB2 signaling modulation

A novel group of 5,6-dihydropyrido [2',1':2,3]imidazo [4,5-c]quinolines was prepared via a microwave assisted one-pot telescopic approach. The synthetic sequence involves the formation of an amine precursor of imidazo [1,2-a]pyridine via condensation and reduction under microwave irradiation. Subsequently, the Pictet-Spengler cyclisation reaction occurs with ketones (cyclic or acyclic) to obtain substituted 5,6-dihydropyrido [2',1':2,3]imidazo [4,5-c]quinolines in excellent yields. The compounds were tested as neuroprotective agents. Observed protection of neuron-like cells, SH-SY5Y differentiated with ATRA, in Parkinson's and Huntington's disease models inspired further mechanistic studies of protective activity against damage induced by 1-methyl-4-phenylpyridinium (MPP+), a compound causing Parkinson's disease. The novel compounds exhibit similar or higher potency than ebselen, an established drug with antioxidant activity, in the cells against MPP + -induced total cellular superoxide production and cell death. However, they exhibit a significantly higher capacity to reduce mitochondrial superoxide and preserve mitochondrial membrane potential. We also observed marked differences between a selected derivative and ebselen in terms of normalizing MPP + -induced phosphorylation of Akt and ERK1/2. The cytoprotective activity was abrogated when signaling through cannabinoid receptor CB2 was blocked. The compounds also inhibit both acetylcholine and butyrylcholine esterases. Overall the data show that novel 5,6-dihydropyrido [2',1':2,3]imidazo [4,5-c]quinoline have a broad cytoprotective activity which is mediated by several mechanisms including mitoprotection.

Metformin instigates cellular autophagy to ameliorate high-fat diet-induced pancreatic inflammation and fibrosis/EMT in mice

BACKGROUND

Chronic pancreatic dysfunction is frequently observed as a consequence of prolonged high-fat diet consumption and is a serious public health concern. This pro-diabetic insult aggravates inflammation-influenced fibrotic lesions and is associated with deregulated autophagy. Metformin, a conventional anti-hyperglycemic drug, might be beneficial for pancreatic health, but the complex molecular regulations are not clarified. Considering the worldwide prevalence of chronic pancreatic dysfunction in obese individuals, we aimed to unwind the molecular intricacies explaining the involvement of oxidative stress, inflammation and fibrosis and to approbate metformin as a plausible intervention in this crossroad.

MAIN METHODS

Age-matched Swiss Albino mice were exposed to high-fat diet (60 kcal%) against control diet (10 kcal%) to establish diet-induced stress model. Metformin treatment was introduced after 4 weeks to metformin-control and HFD-exposed metformin groups. After 8 weeks, metabolic and molecular outcomes were assessed to establish the impact of metformin on chronic consequences of HFD-mediated injury.

KEY FINDINGS

High-fat diet administration to healthy mice primes oxidative stress-mediated chronic inflammation through Nrf2/Keap1/NF-κB interplay. Besides, pro-inflammatory cytokine bias leading to fibrotic (increased TGF-β, α-SMA, and MMP9) and pro-EMT (Twist1, Slug, Vimentin, E-cadherin) repercussions in pancreatic lobules were evident. Metformin distinctly rescues high-fat diet-induced remodeling of pancreatic pro-diabetic alterations and cellular survival/death switch. Further, metformin abrogates the p62-Twist1 crosstalk in an autophagy-dependent manner (elevated beclin1, LC3-II/I, Lamp2) to restore pancreatic homeostasis.

CONCLUSION

Our research validates the therapeutic potential of metformin in the inflammation-fibrosis nexus to ameliorate high-fat diet-induced pancreatic dysfunction and related metabolic alterations.

Plant‐Derived Phytochemicals and Their Nanoformulations for Inducing Programed Cell Death in Cancer

Phytochemicals are a diverse class of compounds found in various plant‐based foods and beverages that have displayed the capacity to exert powerful anticancer effects through the induction of programed cell death (PCD) in malignancies. PCD is a sophisticated process that maintains in upholding tissue homeostasis and eliminating injured or neoplastic cells. Phytochemicals have shown the potential to induce PCD in malignant cells through various mechanisms, including modulation of cell signaling pathways, regulation of reactive oxygen species (ROS), and interaction with critical targets in cells such as DNA. Moreover, recent studies have suggested that nanomaterials loaded with phytochemicals may enhance cell death in tumors, which can also stimulate antitumor immunity. In this review, a comprehensive overview of the current understanding of the anticancer effects of phytochemicals and their potential as a promising approach to cancer therapy, is provided. The impacts of phytochemicals such as resveratrol, curcumin, apigenin, quercetin, and some approved plant‐derived drugs, such as taxanes on the regulation of some types of PCD, including apoptosis, pyroptosis, anoikis, autophagic cell death, ferroptosis, and necroptosis, are discussed. The underlying mechanisms and the potential of nanomaterials loaded with phytochemicals to enhance PCD in tumors are also explained.

GABA(A) Receptor Activation Drives GABARAP-Nix Mediated Autophagy to Radiation-Sensitize Primary and Brain-Metastatic Lung Adenocarcinoma Tumors

In non-small cell lung cancer (NSCLC) treatment, radiotherapy responses are not durable and toxicity limits therapy. We find that AM-101, a synthetic benzodiazepine activator of GABA(A) receptor, impairs the viability and clonogenicity of both primary and brain-metastatic NSCLC cells. Employing a human-relevant ex vivo 'chip', AM-101 is as efficacious as docetaxel, a chemotherapeutic used with radiotherapy for advanced-stage NSCLC. In vivo, AM-101 potentiates radiation, including conferring a significant survival benefit to mice bearing NSCLC intracranial tumors generated using a patient-derived metastatic line. GABA(A) receptor activation stimulates a selective-autophagic response via the multimerization of GABA(A) receptor-associated protein, GABARAP, the stabilization of mitochondrial receptor Nix, and the utilization of ubiquitin-binding protein p62. A high-affinity peptide disrupting Nix binding to GABARAP inhibits AM-101 cytotoxicity. This supports a model of GABA(A) receptor activation driving a GABARAP-Nix multimerization axis that triggers autophagy. In patients receiving radiotherapy, GABA(A) receptor activation may improve tumor control while allowing radiation dose de-intensification to reduce toxicity.

Heat shock proteins as hallmarks of cancer: insights from molecular mechanisms to therapeutic strategies

Heat shock proteins are essential molecular chaperones that play crucial roles in stabilizing protein structures, facilitating the repair or degradation of damaged proteins, and maintaining proteostasis and cellular functions. Extensive research has demonstrated that heat shock proteins are highly expressed in cancers and closely associated with tumorigenesis and progression. The "Hallmarks of Cancer" are the core features of cancer biology that collectively define a series of functional characteristics acquired by cells as they transition from a normal state to a state of tumor growth, including sustained proliferative signaling, evasion of growth suppressors, resistance to cell death, enabled replicative immortality, the induction of angiogenesis, and the activation of invasion and metastasis. The pivotal roles of heat shock proteins in modulating the hallmarks of cancer through the activation or inhibition of various signaling pathways has been well documented. Therefore, this review provides an overview of the roles of heat shock proteins in vital biological processes from the perspective of the hallmarks of cancer and summarizes the small-molecule inhibitors that target heat shock proteins to regulate various cancer hallmarks. Moreover, we further discuss combination therapy strategies involving heat shock proteins and promising dual-target inhibitors to highlight the potential of targeting heat shock proteins for cancer treatment. In summary, this review highlights how targeting heat shock proteins could regulate the hallmarks of cancer, which will provide valuable information to better elucidate and understand the roles of heat shock proteins in oncology and the mechanisms of cancer occurrence and development and aid in the development of more efficacious and less toxic novel anticancer agents.

The Interplay between Autophagy and Mitochondria in Cancer

Besides producing cellular energy, mitochondria are crucial in controlling oxidative stress and modulating cellular metabolism, particularly under stressful conditions. A key aspect of this regulatory role involves the recycling process of autophagy, which helps to sustain energy homeostasis. Autophagy, a lysosome-dependent degradation pathway, plays a fundamental role in maintaining cellular homeostasis by degrading damaged organelles and misfolded proteins. In the context of tumor formation, autophagy significantly influences cancer metabolism and chemotherapy resistance, contributing to both tumor suppression and surveillance. This review focuses on the relationship between mitochondria and autophagy, specifically in the context of cancer progression. Investigating the interaction between autophagy and mitochondria reveals new possibilities for cancer treatments and may result in the development of more effective therapies targeting mitochondria, which could have significant implications for cancer treatment. Additionally, this review highlights the increasing understanding of autophagy's role in tumor development, with a focus on modulating mitochondrial function and autophagy in both pre-clinical and clinical cancer research. It also explores the potential for developing more-targeted and personalized therapies by investigating autophagy-related biomarkers.

Exercise-activated hepatic autophagy combined with silymarin is associated with suppression of apoptosis in rats subjected to dexamethasone induced- fatty liver damage

AIM

There is a need for effective treatments for non-alcoholic fatty liver disease (NAFLD) that are economically inexpensive, and have few side effects. The present study aimed to investigate exercise training and silymarin on hepatocyte death factors in rats with liver damage.

METHODS

Forty-nine male Wistar rats were assigned to seven groups: sedentary control, fatty liver control (DEX), fatty liver + high-intensity interval training (HIIT), fatty liver + HIIT + silymarin (HIIT + SILY), fatty liver + continuous training (CT), fatty liver + CT + silymarin (CT + SILY), and fatty liver + silymarin (SILY). A subcutaneous injection of dexamethasone for 7 days was used to induce fatty liver in rats. Masson's trichrome and hematoxylin-eosin staining were done to evaluate hepatic injury. The hepatocyte apoptosis was determined by TUNEL assay. Real-Time PCR was conducted to evaluate the gene expressions of caspase-9, adenosine monophosphate-activated protein kinase (AMPKα1), mitofusin 2 (Mfn2), and damage-regulated autophagy modulator (DRAM). Liver tissue changes and serum levels of liver enzymes were also evaluated.

RESULTS

Liver apoptosis was decreased in the CT, HIIT, HIIT + SILY and CT + SILY groups compared to the DEX group. Both continuous and high-intensity training models produced beneficial alterations in liver morphology and hepatic injuries that were significant in exercise training + silymarin group. This impact was accompanied by increased AMPKα1 and DRAM gene expression and decreased caspase-9 and Mfn2 gene expression. Liver enzyme levels were high in the DEX group and treatment with silymarin significantly reduced it.

CONCLUSION

Silymarin supplementation combined with interval or continuous training substantially improves DEX-induced hepatic steatosis and hepatocyte injury mostly through suppressing liver apoptosis and upregulating autophagy, which may provide a novel perspective for NAFLD treatment.

Whole-body replacement of larval myofibers generates permanent adult myofibers in zebrafish

Drastic increases in myofiber number and size are essential to support vertebrate post-embryonic growth. However, the collective cellular behaviors that enable these increases have remained elusive. Here, we created the palmuscle myofiber tagging and tracking system for in toto monitoring of the growth and fates of ~5000 fast myofibers in developing zebrafish larvae. Through live tracking of individual myofibers within the same individuals over extended periods, we found that many larval myofibers readily dissolved during development, enabling the on-site addition of new and more myofibers. Remarkably, whole-body surveillance of multicolor-barcoded myofibers further unveiled a gradual yet extensive elimination of larval myofiber populations, resulting in near-total replacement by late juvenile stages. The subsequently emerging adult myofibers are not only long-lasting, but also morphologically and functionally distinct from the larval populations. Furthermore, we determined that the elimination-replacement process is dependent on and driven by the autophagy pathway. Altogether, we propose that the whole-body replacement of larval myofibers is an inherent yet previously unnoticed process driving organismic muscle growth during vertebrate post-embryonic development.

Longitudinal analysis of the lung proteome reveals persistent repair months after mild to moderate COVID-19

In order to assess homeostatic mechanisms in the lung after COVID-19, changes in the protein signature of bronchoalveolar lavage from 45 patients with mild to moderate disease at three phases (acute, recovery, and convalescent) are evaluated over a year. During the acute phase, inflamed and uninflamed phenotypes are characterized by the expression of tissue repair and host defense response molecules. With recovery, inflammatory and fibrogenic mediators decline and clinical symptoms abate. However, at 9 months, quantified radiographic abnormalities resolve in the majority of patients, and yet compared to healthy persons, all showed ongoing activation of cellular repair processes and depression of the renin-kallikrein-kinin, coagulation, and complement systems. This dissociation of prolonged reparative processes from symptom and radiographic resolution suggests that occult ongoing disruption of the lung proteome is underrecognized and may be relevant to recovery from other serious viral pneumonias.

Cuproptosis and Cu: a new paradigm in cellular death and their role in non-cancerous diseases

Cuproptosis, a newly characterized form of regulated cell death driven by copper accumulation, has emerged as a significant mechanism underlying various non-cancerous diseases. This review delves into the complex interplay between copper metabolism and the pathogenesis of conditions such as Wilson's disease (WD), neurodegenerative disorders, and cardiovascular pathologies. We examine the molecular mechanisms by which copper dysregulation induces cuproptosis, highlighting the pivotal roles of key copper transporters and enzymes. Additionally, we evaluate the therapeutic potential of copper chelation strategies, which have shown promise in experimental models by mitigating copper-induced cellular damage and restoring physiological homeostasis. Through a comprehensive synthesis of recent advancements and current knowledge, this review underscores the necessity of further research to translate these findings into clinical applications. The ultimate goal is to harness the therapeutic potential of targeting cuproptosis, thereby improving disease management and patient outcomes in non-cancerous conditions associated with copper dysregulation.

Mitigation of benzyl butyl phthalate toxicity in male germ cells with combined treatment of parthenolide, N-acetylcysteine, and 3-methyladenine

Benzyl butyl phthalate (BBP) is a widely used plasticizer that poses various potential health hazards. Although BBP has been extensively studied, the direct mechanism underlying its toxicity in male germ cells remains unclear. Therefore, we investigated BBP-mediated male germ cell toxicity in GC-1 spermatogonia (spg), a differentiated mouse male germ cell line. This study investigated the impact of BBP on reactive oxygen species (ROS) generation, apoptosis, and autophagy regulation, as well as potential protective measures against BBP-induced toxicity. A marked dose-dependent decrease in GC-1 spg cell proliferation was observed following treatment with BBP at 12.5 μM. Exposure to 50 μM BBP, approximating the IC50 of 53.9 μM, markedly increased cellular ROS generation and instigated apoptosis, as evidenced by augmented protein levels of both intrinsic and extrinsic apoptosis-related markers. An amount of 50 μM BBP induced marked upregulation of autophagy regulator proteins, p38 MAPK, and extracellular signal-regulated kinase and substantially downregulated the phosphorylation of key kinases involved in regulating cell proliferation, including phosphoinositide 3-kinase, protein kinase B, mammalian target of rapamycin (mTOR), c-Jun N-terminal kinase. The triple combination of N-acetylcysteine, parthenolide, and 3-methyladenine markedly restored cell proliferation, decreased BBP-induced apoptosis and autophagy, and restored mTOR phosphorylation. This study provides new insights into BBP-induced male germ cell toxicity and highlights the therapeutic potential of the triple inhibitors in mitigating BBP toxicity.

Mechanism of motoneuronal and pyramidal cell death in amyotrophic lateral sclerosis and its potential therapeutic modulation

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder clinically characterized by muscle atrophy and progressive paralysis. Loss of motoneurons and pyramidal cells is thought to be the center piece of the complex and multifaceted ALS pathology, however, the exact mechanisms laying behind motoneuronal cell death in the spinal cord and motor cortex are still unknown. It was originally proposed that apoptosis plays a fundamental role in motoneuronal demise, nonetheless, later it became clear that other forms of regulated cell death, including necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death, may also contribute to motoneuron loss. Over the past years, multiple studies aimed to improve our understanding of the contributory role of these mechanisms as well as to offer novel targets for potential therapeutic interventions. The pharmacological inhibition of the ferroptotic pathway and the modulation of the autophagic machinery seem to have particularly promising effects, reducing motoneuron loss and slowing disease progression in transgenic models of ALS. Nevertheless, the potential beneficial effects of necroptosis-targeting interventions were mostly disproven in the latest studies. In this review we aim to summarize the current view on regulated cell death mechanisms that lead to motoneuronal and pyramidal cell degeneration in ALS and showcase their applicability as future drug targets.

Biosensors; a novel concept in real-time detection of autophagy

Autophagy is an early-stage response with self-degradation properties against several insulting conditions. To date, the critical role of autophagy has been well-documented in physiological and pathological conditions. This process involves various signaling and functional biomolecules, which are involved in different steps of the autophagic response. During recent decades, a range of biochemical analyses, chemical assays, and varied imaging techniques have been used for monitoring this pathway. Due to the complexity and dynamic aspects of autophagy, the application of the conventional methodology for following autophagic progression is frequently associated with a mistake in discrimination between a complete and incomplete autophagic response. Biosensors provide a de novo platform for precise and accurate analysis of target molecules in different biological settings. It has been suggested that these devices are applicable for real-time monitoring and highly sensitive detection of autophagy effectors. In this review article, we focus on cutting-edge biosensing technologies associated with autophagy detection.

Nanomaterials-based advanced systems for photothermal / photodynamic therapy of oral cancer

The traditional clinical approaches for oral cancer consist of surgery, chemotherapy, radiotherapy, immunotherapy, and so on. However, these treatments often induce side effects and exhibit limited efficacy. Photothermal therapy (PTT) emerges as a promising adjuvant treatment, utilizing photothermal agents (PTAs) to convert light energy into heat for tumor ablation. Another innovative approach, photodynamic therapy (PDT), leverages photosensitizers (PSs) and specific wavelength laser irradiation to generate reactive oxygen species (ROS), offering an effective and non-toxic alternative. The relevant combination therapies have been reported in the field of oral cancer. Simultaneously, the advancement of nanomaterials has propelled the clinical application of PTT and PDT. Therefore, a comprehensive understanding of PTT and PDT is required for better application in oral cancer treatment. Here, we review the use of PTT and PDT in oral cancer, including noble metal materials (e.g., Au nanoparticles), carbon materials (e.g., graphene oxide), organic dye molecules (e.g., indocyanine green), organic molecule-based agents (e.g., porphyrin-analog phthalocyanine) and other inorganic materials (e.g., MXenes), exemplify the advantages and disadvantages of common PTAs and PSs, and summarize the combination therapies of PTT with PDT, PTT/PDT with chemotherapy, PTT with radiotherapy, PTT/PDT with immunotherapy, and PTT/PDT with gene therapy in the treatment of oral cancer. The challenges related to the PTT/PDT combination therapy and potential solutions are also discussed.

The relation between autophagy modulation by intermittent fasting and aquaporin 2 expression in experimentally induced diabetic nephropathy in albino rat

Polyuria is an early sign of diabetic nephropathy (DN) that produces dehydration in diabetic patients. This could be caused by alteration of renal aquaporin 2 (AQP2) expression. This study aimed to describe the relation between autophagy modulation via intermittent fasting (IF) and renal AQP2 expression and polyuria in case of DN. We divided the rats into control, DN and IF groups. After 2 and 4 weeks of diabetes induction, blood glucose (BG), serum creatinine (Scr), urine volume, and 24 hours urine protein (UP) were examined. Diabetic nephropathy histopathological index (DNHI) was calculated to evaluate histopathological changes. Immunohistochemistry and real-time PCR were performed to measure the levels of AQP2 and the autophagy marker; LC3 in kidney tissue. DNHI was correlated to the PCR and immunoexpression of AQP2 and LC3. Intermittent fasting significantly decreased the BG, Scr, urine volume, 24 hours UP, and DNHI as compared diabetes. Diabetes significantly elevated the immunoreactivity and mRNA expression levels of AQP2 and LC3 as compared to the control. However, the IF decreased AQP2 and stimulated autophagy in cyclic fashion. Our data revealed significant positive correlations between AQP2 and LC3 at the level of immunoexpression and mRNA at 2nd weeks. Taken together, these data showed that autophagy stimulation didn't regulate AQP2 expression in case of diabetic nephropathy, however IF decreased polyuria through improvement of glycemic state.

Nobiletin targets SREBP1/ACLY to induce autophagy-dependent cell death of gastric cancer cells through PI3K/Akt/mTOR signaling pathway

BACKGROUND

Autophagy could sense metabolic conditions and safeguard cells against nutrient deprivation, ultimately supporting the survival of cancer cells. Nobiletin (NOB) is a kind of bioactive component of the traditional Chinese medicine Citri Reticulatae Pericarpium and has been proven to induce GC cell death by reducing de novo fatty acid synthesis in our previous study. Nevertheless, the precise mechanisms by which NOB induces cell death in GC cells still need further elucidation.

OBJECTIVES

To examine the mechanism by which NOB inhibits gastric cancer progression through the regulation of autophagy under the condition of lipid metabolism inhibition.

METHODS/ STUDY DESIGN

Proliferation was detected by the CCK-8 assay. RNA sequencing (RNA-seq) was used to examine signaling pathway changes. Electron microscopy and mRFP-GFP-LC3 lentiviral transfection were performed to observe autophagy in vitro. Western blot, plasmid transfection, immunofluorescence staining, and CUT & Tag-qPCR techniques were utilized to explore the mechanisms by which NOB affects GC cells. Molecular docking and molecular dynamics simulations were conducted to predict the binding mode of NOB and SREBP1. CETSA was adopted to verify the predicted of binding model. A patient-derived xenograft (PDX) model was employed to verify the therapeutic efficacy of NOB in vivo.

RESULTS

We conducted functional studies and discovered that NOB inhibited the protective effect of autophagy via the PI3K/Akt/mTOR axis in GC cells. Based on previous research, we found that the overexpression of ACLY abrogated the NOB-induced autophagy-dependent cell death. In silico analysis predicted the formation of a stable complex between NOB and SREBP1. In vitro assays confirmed that NOB treatment increased the thermal stability of SREBP1 at the same temperature conditions. Moreover, CUT&TAG-qPCR analysis revealed that NOB could inhibit SREBP1 binding to the ACLY promoter. In the PDX model, NOB suppressed tumor growth, causing SREBP1 nuclear translocation inhibition, PI3K/Akt/mTOR inactivation, and autophagy-dependent cell death.

CONCLUSION

NOB demonstrated the ability to directly bind to SREBP1, inhibiting its nuclear translocation and binding to the ACLY promoter, thereby inducing autophagy-dependent cell death via PI3K/Akt/mTOR pathway.

Analysis of Gingival Fibroblasts Behaviour in the Presence of 3D-Printed versus Milled Methacrylate-Based Dental Resins-Do We Have a Winner?

Computer-aided design and computer-aided manufacturing (CAD/CAM) techniques are based on either subtractive (milling prefabricated blocks) or additive (3D printing) methods, and both are used for obtaining dentistry materials. Our in vitro study aimed to investigate the behavior of human gingival fibroblasts exposed to methacrylate (MA)-based CAD/CAM milled samples in comparison with that of MA-based 3D-printed samples to better elucidate the mechanisms of cell adaptability and survival. The proliferation of human gingival fibroblasts was measured after 2 and 24 h of incubation in the presence of these samples using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the membrane integrity was assessed through the lactate dehydrogenase release. The level of reactive oxygen species, expression of autophagy-related protein LC3B-I, and detection of GSH and caspase 3/7 were evaluated by fluorescence staining. The MMP-2 levels were measured using a Milliplex MAP kit. The incubation with MA-based 3D-printed samples significantly reduced the viability, by 16% and 28% from control after 2 and 24 h, respectively. There was a 25% and 55% decrease in the GSH level from control after 24 h of incubation with the CAD/CAM milled and 3D-printed samples, respectively. In addition, higher levels of LC3B-I and MMP-2 were obtained after 24 h of incubation with the MA-based 3D samples compared to the CAD/CAM milled ones. Therefore, our results outline that the MA-CAD/CAM milled samples displayed good biocompatibility during 24-h exposure, while MA-3D resins are proper for short-term utilization (less than 24 h).

Structural variety and pharmacological potential of naphthylisoquinoline alkaloids

Naphthylisoquinoline alkaloids are a fascinating class of natural biaryl compounds. They show characteristic mono- and dimeric scaffolds, with chiral axes and stereogenic centers. Since the appearance of the last comprehensive overview on these secondary plant metabolites in this series in 1995, the number of discovered representatives has tremendously increased to more than 280 examples known today. Many novel-type compounds have meanwhile been discovered, among them naphthylisoquinoline-related follow-up products like e.g., the first seco-type (i.e., ring-opened) and ring-contracted analogues. As highlighted in this review, the knowledge on the broad structural chemodiversity of naphthylisoquinoline alkaloids has been decisively driven forward by extensive phytochemical studies on the metabolite pattern of Ancistrocladus abbreviatus from Coastal West Africa, which is a particularly "creative" plant. These investigations furnished a considerable number of more than 80-mostly new-natural products from this single species, with promising antiplasmodial activities and with pronounced cytotoxic effects against human leukemia, pancreatic, cervical, and breast cancer cells. Another unique feature of naphthylisoquinoline alkaloids is their unprecedented biosynthetic origin from polyketidic precursors and not, as usual for isoquinoline alkaloids, from aromatic amino acids-a striking example of biosynthetic convergence in nature. Furthermore, remarkable botanical results are presented on the natural producers of naphthylisoquinoline alkaloids, the paleotropical Dioncophyllaceae and Ancistrocladaceae lianas, including first investigations on the chemoecological role of these plant metabolites and their storage and accumulation in particular plant organs.

Finding a Direct Method for a Dynamic Process: The DD (Direct and Dynamic) Cell-Tox Method

The main focus of in vitro toxicity assessment methods is to assess the viability of the cells, which is usually based on metabolism changes. Yet, when exposed to toxic substances, the cell triggers multiple signals in response. With this in mind, we have developed a promising cell-based toxicity method that observes various cell responses when exposed to toxic substances (either death, division, or remain viable). Based on the collective cell response, we observed and predicted the dynamics of the cell population to determine the toxicity of the toxicant. The method was tested with two different conformations: In the first conformation, we exposed a monoculture model of blood macrophages to UV light, hydrogen peroxide, nutrient deprivation, tetrabromobisphenol A, fatty acids, and 5-fluorouracil. In the second, we exposed a coculture liver model consisting of hepatocytes, hepatic stellate cells, Kupffer cells, and liver sinusoidal endothelial cells to rifampicin, ibuprofen, and 5-fluorouracil. The method showed good accuracy compared to established toxicity assessment methods. In addition, this approach provided more representative information on the toxic effects of the compounds, as it considers the different cellular responses induced by toxic agents.

USP24-i-101 targeting of USP24 activates autophagy to inhibit drug resistance acquired during cancer therapy

Drug resistance in cancer therapy is the major reason for poor prognosis. Addressing this clinically unmet issue is important and urgent. In this study, we found that targeting USP24 by the specific USP24 inhibitors, USP24-i and its analogues, dramatically activated autophagy in the interphase and mitotic periods of lung cancer cells by inhibiting E2F4 and TRAF6, respectively. USP24 functional knockout, USP24C1695A, or targeting USP24 by USP24-i-101 inhibited drug resistance and activated autophagy in gefitinib-induced drug-resistant mice with doxycycline-induced EGFRL858R lung cancer, but this effect was abolished after inhibition of autophagy, indicating that targeting USP24-mediated induction of autophagy is required for inhibition of drug resistance. Genomic instability and PD-L1 levels were increased in drug resistant lung cancer cells and were inhibited by USP24-i-101 treatment or knockdown of USP24. In addition, inhibition of autophagy by bafilomycin-A1 significantly abolished the effect of USP24-i-101 on maintaining genomic integrity, decreasing PD-L1 and inhibiting drug resistance acquired in chemotherapy or targeted therapy. In summary, an increase in the expression of USP24 in cancer cells is beneficial for the induction of drug resistance and targeting USP24 by USP24-i-101 optimized from USP24-i inhibits drug resistance acquired during cancer therapy by increasing PD-L1 protein degradation and genomic stability in an autophagy induction-dependent manner.

Oleuropein activates autophagy to circumvent anti-plasmodial defense

Antimalarial drug resistance and unavailability of effective vaccine warrant for newer drugs and drug targets. Hence, anti-inflammatory activity of phyto-compound (oleuropein; OLP) was determined in antigen (LPS)-stimulated human THP-1 macrophages (macrophage model of inflammation; MMI). Reduction in the inflammation was controlled by the PI3K-Akt1 signaling to establish the "immune-homeostasis." Also, OLP treatment influenced the cell death/autophagy axis leading to the modulated inflammation for extended cell survival. The findings with MII prompted us to detect the antimalarial activity of OLP in the wild type (3D7), D10-expressing GFP-Atg18 parasite, and chloroquine-resistant (Dd2) parasite. OLP did not show the parasite inhibition in the routine in vitro culture of P. falciparum whereas OLP increased the antimalarial activity of artesunate. The molecular docking of autophagy-related proteins, investigations with MMI, and parasite inhibition assays indicated that the host activated the autophagy to survive OLP pressure. The challenge model of P. berghei infection showed to induce autophagy for circumventing anti-plasmodial defenses.

Identification and In Vivo Validation of Unique Anti-Oncogenic Mechanisms Involving Protein Kinase Signaling and Autophagy Mediated by the Investigational Agent PV-10

PV-10 is a 10% formulation of rose bengal sodium that has potent immunotherapeutic and anti-cancer activity against various tumors, including metastatic melanoma and refractory neuroblastoma. Currently, PV-10 is undergoing clinical testing for refractory metastatic neuroendocrine cancer and melanomas. However, preclinical investigation of PV-10 activity and its mechanisms against phenotypically and molecularly diverse adult solid tumors had not been conducted. In a panel of human cell lines derived from breast, colorectal, head and neck, and testicular cancers, we demonstrated that PV-10 induces cytotoxicity by apoptotic and autophagic pathways involving caspase-mediated PARP cleavage, downregulation of SQSTM1/p62, and upregulation of beclin-1. Treatment with PV-10 also consistently reduced phosphorylation of WNK1, which has been implicated in cancer cell migration and autophagy inhibition. By wound healing assay, PV-10 treatment inhibited the migration of cancer cells. Finally, significant inhibition of tumor growth was also noted in tumor-bearing mice treated with PV-10 by intralesional or systemic administration. In addition to known PV-10-mediated tumor-specific cytotoxic effects, we identified the mechanisms of PV-10 and provide new insights into its effect on autophagy and metastasis. Our data provide essential mechanism-based evidence and biomarkers of activity to formulate clinical studies of PV-10 in the future.

Association of G protein-coupled receptor 78 with salivary dysfunction in male Sjögren's patients

OBJECTIVE

Sjögren's disease (SjD) has a strong sex bias, suggesting an association with sex hormones. Male SjD represents a distinct subset of the disease, but the pathogenic mechanisms of male SjD is poorly characterized. The aim of this study is to identify initiating events related to the development of gland hypofunction and autoimmunity in male SjD patients.

MATERIALS AND METHODS

Human minor salivary glands were transcriptomically analyzed with microarrays to detect differentially expressed genes in male SjD patients. Identified genes were tested on their involvement in the disease using conditional transgenic mice and gene-overexpressing cells.

RESULTS

GPR78, an orphan G protein-coupled receptor, was overexpressed in the salivary glands of male SjD patients compared with male healthy controls and female SjD patients. Male GPR78 transgenic mice developed salivary gland hypofunction with increased epithelial apoptosis, which was not seen in control or female transgenic mice. In cell culture, GPR78 overexpression decreased lysosomal integrity, leading to caspase-dependent apoptotic cell death. GPR78-induced cell death in vitro was inhibited by treatment with estradiol.

CONCLUSION

GPR78 overexpression can induce apoptosis and salivary gland hypofunction in male mice through lysosomal dysfunction and increased caspase-dependent apoptosis in salivary gland epithelium, which may drive disease in humans.

Bisphenol A induces placental ferroptosis and fetal growth restriction via the YAP/TAZ-ferritinophagy axis

Exposure to bisphenol A (BPA) during gestation leads to fetal growth restriction (FGR), whereby the underlying mechanisms remain unknown. Here, we found that FGR patients showed higher levels of BPA in the urine, serum, and placenta; meanwhile, trophoblast ferroptosis was observed in FGR placentas, as indicated by accumulated intracellular iron, impaired antioxidant molecules, and increased lipid peroxidation products. To investigate the role of ferroptosis in placental and fetal growth, BPA stimulation was performed both in vivo and in vitro. BPA exposure during gestation was associated with FGR in mice; also, it induces ferroptosis in mouse placentas and human placental trophoblast. Pretreatment with ferroptosis inhibitor ferritin-1 (Fer-1) alleviated BPA-induced oxidative damage and cell death. Notably, BPA reduced the trophoblastic expression of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), which regulated tissue growth and organ size. YAP or TAZ siRNA enhanced BPA-induced ferroptosis, suggesting that trophoblast ferroptosis is dependent on YAP/TAZ downregulation after BPA stimulation. Consistently, the protein levels of YAP/TAZ were also reduced in FGR placentas. Further results revealed that silencing YAP/TAZ promoted BPA-induced ferroptosis through autophagy. Pretreatment with autophagy inhibitor chloroquine (CQ) attenuated BPA-induced trophoblast ferroptosis. Ferritinophagy, an autophagic degradation of ferritin (FTH1), was observed in FGR placentas. Similarly, BPA reduced the protein level of FTH1 in placental trophoblast. Pretreatment with iron chelator desferrioxamine (DFO) and NCOA4 (an autophagy cargo receptor) siRNA weakened the ferroptosis of trophoblast after exposure to BPA, indicating that autophagy mediates ferroptosis in BPA-stimulated trophoblast by degrading ferritin. In summary, ferroptosis was featured in BPA-associated FGR and trophoblast injury; the regulation of ferroptosis involved the YAP/TAZ-autophagy-ferritin axis.

Bisphenol A induces placental ferroptosis and fetal growth restriction via the YAP/TAZ-ferritinophagy axis

Exposure to bisphenol A (BPA) during gestation leads to fetal growth restriction (FGR), whereby the underlying mechanisms remain unknown. Here, we found that FGR patients showed higher levels of BPA in the urine, serum, and placenta; meanwhile, trophoblast ferroptosis was observed in FGR placentas, as indicated by accumulated intracellular iron, impaired antioxidant molecules, and increased lipid peroxidation products. To investigate the role of ferroptosis in placental and fetal growth, BPA stimulation was performed both in vivo and in vitro. BPA exposure during gestation was associated with FGR in mice; also, it induces ferroptosis in mouse placentas and human placental trophoblast. Pretreatment with ferroptosis inhibitor ferritin-1 (Fer-1) alleviated BPA-induced oxidative damage and cell death. Notably, BPA reduced the trophoblastic expression of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), which regulated tissue growth and organ size. YAP or TAZ siRNA enhanced BPA-induced ferroptosis, suggesting that trophoblast ferroptosis is dependent on YAP/TAZ downregulation after BPA stimulation. Consistently, the protein levels of YAP/TAZ were also reduced in FGR placentas. Further results revealed that silencing YAP/TAZ promoted BPA-induced ferroptosis through autophagy. Pretreatment with autophagy inhibitor chloroquine (CQ) attenuated BPA-induced trophoblast ferroptosis. Ferritinophagy, an autophagic degradation of ferritin (FTH1), was observed in FGR placentas. Similarly, BPA reduced the protein level of FTH1 in placental trophoblast. Pretreatment with iron chelator desferrioxamine (DFO) and NCOA4 (an autophagy cargo receptor) siRNA weakened the ferroptosis of trophoblast after exposure to BPA, indicating that autophagy mediates ferroptosis in BPA-stimulated trophoblast by degrading ferritin. In summary, ferroptosis was featured in BPA-associated FGR and trophoblast injury; the regulation of ferroptosis involved the YAP/TAZ-autophagy-ferritin axis.

Exploration of anti‑osteosarcoma activity of asiatic acid based on network pharmacology and in vitro experiments

Osteosarcomas are malignant bone tumors that typically originate in the epiphyses of the long bones of the extremities in adolescents. Asiatic acid has been reported to possess anti‑inflammatory, neuroprotective, antidiabetic, antitumor and antimicrobial activities. The present study used a combination of network pharmacological prediction and in vitro experimental validation to explore the potential pharmacological mechanism of asiatic acid against osteosarcoma. A total of 78 potential asiatic acid targets in osteosarcoma were identified using databases. Kyoto Encyclopedia of Genes and Genomes analysis indicated that the PI3K/AKT and MAPK signaling pathways are essential in the treatment of osteosarcoma with asiatic acid. Molecular docking revealed binding of asiatic acid to EGFR, Caspase‑3, ESR1, HSP90AA1, IL‑6 and SRC proteins. asiatic acid inhibited proliferation through G2/M cell cycle arrest in osteosarcoma cells. In addition, asiatic acid induced mitochondria‑dependent apoptosis as demonstrated by increases in Bax and VDAC1 expression, and a decrease in Bcl‑2 protein expression. The increased autophagosomes, increased LC3‑II/I ratios and decreased p62 expression in the treatment group indicated that asiatic acid triggered autophagy. In addition, asiatic acid decreased the levels of phosphorylated (p‑)PI3K/PI3K and p‑AKT/AKT, increased reactive oxygen species (ROS) and upregulated the levels of p‑ERK1/2/ERK1/2, p‑p38/p38 and p‑JNK/JNK in osteosarcoma cells. These results demonstrated that asiatic acid inhibited osteosarcoma cells proliferation by inhibiting PI3K/AKT and activating ROS/MAPK signaling pathways, suggesting asiatic acid is a potential agent against osteosarcoma.

Chloroquine and Chemotherapeutic Compounds in Experimental Cancer Treatment

Chloroquine (CQ) and its derivate hydroxychloroquine (HCQ), the compounds with recognized ability to suppress autophagy, have been tested in experimental works and in clinical trials as adjuvant therapy for the treatment of tumors of different origin to increase the efficacy of cytotoxic agents. Such a strategy can be effective in overcoming the resistance of cancer cells to standard chemotherapy or anti-angiogenic therapy. This review presents the results of the combined application of CQ/HCQ with conventional chemotherapy drugs (doxorubicin, paclitaxel, platinum-based compounds, gemcitabine, tyrosine kinases and PI3K/Akt/mTOR inhibitors, and other agents) for the treatment of different malignancies obtained in experiments on cultured cancer cells, animal xenografts models, and in a few clinical trials. The effects of such an approach on the viability of cancer cells or tumor growth, as well as autophagy-dependent and -independent molecular mechanisms underlying cellular responses of cancer cells to CQ/HCQ, are summarized. Although the majority of experimental in vitro and in vivo studies have shown that CQ/HCQ can effectively sensitize cancer cells to cytotoxic agents and increase the potential of chemotherapy, the results of clinical trials are often inconsistent. Nevertheless, the pharmacological suppression of autophagy remains a promising tool for increasing the efficacy of standard chemotherapy, and the development of more specific inhibitors is required.

Effect of ATG8 or SAC1 deficiency on the cell proliferation and lifespan of the long-lived PMT1 deficiency yeast cells

Autophagy is pivotal in maintaining intracellular homeostasis, which involves various biological processes, including cellular senescence and lifespan modulation. Being an important member of the protein O-mannosyltransferase (PMT) family of enzymes, Pmt1p deficiency can significantly extend the replicative lifespan (RLS) of yeast cells through an endoplasmic reticulum (ER) unfolded protein response (UPR) pathway, which is participated in protein homeostasis. Nevertheless, the mechanisms that Pmt1p regulates the lifespan of yeast cells still need to be explored. In this study, we found that the long-lived PMT1 deficiency strain (pmt1Δ) elevated the expression levels of most autophagy-related genes, the expression levels of total GFP-Atg8 fusion protein and free GFP protein compared with wild-type yeast strain (BY4742). Moreover, the long-lived pmt1Δ strain showed the greater dot-signal accumulation from GFP-Atg8 fusion protein in the vacuole lumen through a confocal microscope. However, deficiency of SAC1 or ATG8, two essential components of the autophagy process, decreased the cell proliferation ability of the long-lived pmt1Δ yeast cells, and prevented the lifespan extension. In addition, our findings demonstrated that overexpression of ATG8 had no potential effect on the RLS of the pmt1Δ yeast cells, and the maintained incubation of minimal synthetic medium lacking nitrogen (SD-N medium as starvation-induced autophagy) inhibited the cell proliferation ability of the pmt1Δ yeast cells with the culture time, and blocked the lifespan extension, especially in the SD-N medium cultured for 15 days. Our results suggest that the long-lived pmt1Δ strain enhances the basal autophagy activity, while deficiency of SAC1 or ATG8 decreases the cell proliferation ability and shortens the RLS of the long-lived pmt1Δ yeast cells. Moreover, the maintained starvation-induced autophagy impairs extension of the long-lived pmt1Δ yeast cells, and even leads to the cell death.

Upregulation of ATG9b by propranolol promotes autophagic cell death of hepatic stellate cells to improve liver fibrosis

Proranolol has long been recommended to prevent variceal bleeding in patients with cirrhosis. However, the mechanisms of propranolol in liver fibrosis have not yet been thoroughly elucidated. Autophagic cell death (ACD) of activated hepatic stellate cells (HSCs) is important in the alleviation of liver fibrosis. Our study aims to assess the mechanisms of propranolol regulating HSC ACD and liver fibrosis. ACD of HSCs was investigated using lentivirus transfection. The molecular mechanism was determined using a PCR profiler array. The role of autophagy-related protein 9b (ATG9b) in HSC ACD was detected using co-immunoprecipitation and co-localization of immunofluorescence. Changes in the signalling pathway were detected by the Phospho Explorer antibody microarray. Propranolol induces ACD and apoptosis in HSCs. ATG9b upregulation was detected in propranolol-treated HSCs. ATG9b upregulation promoted ACD of HSCs and alleviated liver fibrosis in vivo. ATG9b enhanced the P62 recruitment to ATG5-ATG12-LC3 compartments and increased the co-localization of P62 with ubiquitinated proteins. The PI3K/AKT/mTOR pathway is responsible for ATG9b-induced ACD in activated HSCs, whereas the p38/JNK pathway is involved in apoptosis. This study provides evidence for ATG9b as a new target gene and propranolol as an agent to alleviate liver fibrosis by regulating ACD of activated HSCs.

Fructose-Induced mTORC1 Activation Promotes Pancreatic Cancer Progression through Inhibition of Autophagy

Excessive fructose intake is associated with the occurrence, progression, and poor prognosis of various tumors. A better understanding of the mechanisms underlying the functions of fructose in cancer could facilitate the development of better treatment and prevention strategies. In this study, we investigated the functional association between fructose utilization and pancreatic ductal adenocarcinoma (PDAC) progression. Fructose could be taken up and metabolized by PDAC cells and provided an adaptive survival mechanism for PDAC cells under glucose-deficient conditions. GLUT5-mediated fructose metabolism maintained the survival, proliferation, and invasion capacities of PDAC cells in vivo and in vitro. Fructose metabolism not only provided ATP and biomass to PDAC cells but also conferred metabolic plasticity to the cells, making them more adaptable to the tumor microenvironment. Mechanistically, fructose activated the AMP-activated protein kinase (AMPK)-mTORC1 signaling pathway to inhibit glucose deficiency-induced autophagic cell death. Moreover, the fructose-specific transporter GLUT5 was highly expressed in PDAC tissues and was an independent marker of disease progression in patients with PDAC. These findings provide mechanistic insights into the role of fructose in promoting PDAC progression and offer potential strategies for targeting metabolism to treat PDAC.

SIGNIFICANCE

Fructose activates AMPK-mTORC1 signaling to inhibit autophagy-mediated cell death in pancreatic cancer cells caused by glucose deficiency, facilitating metabolic adaptation to the tumor microenvironment and supporting tumor growth.

Cytotoxic effect of Ziziphus Spina-Christi extract alone and in combination with doxorubicin on breast cancer cells

Ziziphus Spina-Christi (L.) (ZSC) is a traditional Arabian medicinal plant used to treat inflammatory symptoms, swellings and pain since long. Triple negative breast cancer (TNBC) is a form of cancer with a poor prognosis owing to the paucity of therapy alternatives. Two of the most critical pathways of TNBC development are Wnt/β-catenin signaling and autophagy. In the present study, we intended to identify the possible mechanisms of the cytotoxic effects mediated by ZSC extract on MDA-MB-231 breast cancer cells and to improve the efficacy of DOX in combination with ZSC. The MTT test was used to estimate cell viability and IC50 values. Apoptosis was detected using AnnexinV-FITC detection kit. ELISA was used to measure caspase-3 levels. Cell cycle and the level of autophagosome marker LC3-II were analysed using flow cytometry. Acidic vesicular organelle (AVOs) formation was observed by fluorescence microscopy. Real-time PCR was used to monitor changes in gene expression of β-catenin and autophagic adapter NBR1. It was shown that ZSC treatment dose-dependently inhibited MDA-MB-231 cell viability and induced apoptosis with accompanying elevation of caspase-3 level. Besides ZSC caused a significant elevation in LC3II level and downregulation of NBR1 gene expression with subsequent downregulation of β-catenin gene expression, indicating the inhibition of the oncogenic Wnt pathway. ZSC and DOX combination had synergistic cytotoxic effect by more effective suppression of Wnt pathway and induction of apoptosis and autosis. Keywords: apoptosis, autophagic adapter NBR1, autophagosome marker LC3-II, breast cancer cells, DOX, Wnt/β-catenin signaling, Ziziphus Spina-Christi

GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiation-sensitize primary and brain-metastatic lung adenocarcinoma tumors

In non-small cell lung cancer (NSCLC) treatment, targeted therapies benefit only a subset of NSCLC, while radiotherapy responses are not durable and toxicity limits therapy. We find that a GABA(A) receptor activator, AM-101, impairs viability and clonogenicity of NSCLC primary and brain metastatic cells. Employing an ex vivo 'chip', AM-101 is as efficacious as the chemotherapeutic docetaxel, which is used with radiotherapy for advanced-stage NSCLC. In vivo , AM-101 potentiates radiation, including conferring a survival benefit to mice bearing NSCLC intracranial tumors. GABA(A) receptor activation stimulates a selective-autophagic response via multimerization of GABA(A) Receptor-Associated Protein (GABARAP), stabilization of mitochondrial receptor Nix, and utilization of ubiquitin-binding protein p62. A targeted-peptide disrupting Nix binding to GABARAP inhibits AM-101 cytotoxicity. This supports a model of GABA(A) receptor activation driving a GABARAP-Nix multimerization axis triggering autophagy. In patients receiving radiotherapy, GABA(A) receptor activation may improve tumor control while allowing radiation dose de-intensification to reduce toxicity.

Highlights

Activating GABA(A) receptors intrinsic to lung primary and metastatic brain cancer cells triggers a cytotoxic response. GABA(A) receptor activation works as well as chemotherapeutic docetaxel in impairing lung cancer viability ex vivo . GABA(A) receptor activation increases survival of mice bearing lung metastatic brain tumors.A selective-autophagic response is stimulated by GABA(A) receptor activation that includes multimerization of GABARAP and Nix.Employing a new nanomolar affinity peptide that abrogates autophagosome formation inhibits cytotoxicity elicited by GABA(A) receptor activation.

Insights into DNMT1 and programmed cell death in diseases

DNMT1 (DNA methyltransferase 1) is the predominant member of the DNMT family and the most abundant DNMT in various cell types. It functions as a maintenance DNMT and is involved in various diseases, including cancer and nervous system diseases. Programmed cell death (PCD) is a fundamental mechanism that regulates cell proliferation and maintains the development and homeostasis of multicellular organisms. DNMT1 plays a regulatory role in various types of PCD, including apoptosis, autophagy, necroptosis, ferroptosis, and others. DNMT1 is closely associated with the development of various diseases by regulating key genes and pathways involved in PCD, including caspase 3/7 activities in apoptosis, Beclin 1, LC3, and some autophagy-related proteins in autophagy, glutathione peroxidase 4 (GPX4) and nuclear receptor coactivator 4 (NCOA4) in ferroptosis, and receptor-interacting protein kinase 1-receptor-interacting protein kinase 3-mixed lineage kinase domain-like protein (RIPK1-RIPK3-MLKL) in necroptosis. Our study summarizes the regulatory relationship between DNMT1 and different types of PCD in various diseases and discusses the potential of DNMT1 as a common regulatory hub in multiple types of PCD, offering a perspective for therapeutic approaches in disease.

Combinatorial Treatment with PARP and MAPK Inhibitors Overcomes Phenotype Switch-Driven Drug Resistance in Advanced Melanoma

Metastatic melanoma is either intrinsically resistant or rapidly acquires resistance to targeted therapy treatments, such as MAPK inhibitors (MAPKi). A leading cause of resistance to targeted therapy is a dynamic transition of melanoma cells from a proliferative to a highly invasive state, a phenomenon called phenotype switching. Mechanisms regulating phenotype switching represent potential targets for improving treatment of patients with melanoma. Using a drug screen targeting chromatin regulators in patient-derived three-dimensional MAPKi-resistant melanoma cell cultures, we discovered that PARP inhibitors (PARPi) restore sensitivity to MAPKis, independent of DNA damage repair pathways. Integrated transcriptomic, proteomic, and epigenomic analyses demonstrated that PARPis induce lysosomal autophagic cell death, accompanied by enhanced mitochondrial lipid metabolism that ultimately increases antigen presentation and sensitivity to T-cell cytotoxicity. Moreover, transcriptomic and epigenetic rearrangements induced by PARP inhibition reversed epithelial-mesenchymal transition-like phenotype switching, which redirected melanoma cells toward a proliferative and MAPKi-sensitive state. The combination of PARP and MAPKis synergistically induced cancer cell death both in vitro and in vivo in patient-derived xenograft models. Therefore, this study provides a scientific rationale for treating patients with melanoma with PARPis in combination with MAPKis to abrogate acquired therapy resistance.

SIGNIFICANCE

PARP inhibitors can overcome resistance to MAPK inhibitors by activating autophagic cell death and reversing phenotype switching, suggesting that this synergistic combination could help improve the prognosis of patients with melanoma.

Curcumin induces mitophagy by promoting mitochondrial succinate dehydrogenase activity and sensitizes human papillary thyroid carcinoma BCPAP cells to radioiodine treatment

Thyroid cancer is one of the most common endocrine malignancies. Differentiated thyroid cancer (DTC) treatment is based on the ability of thyroid follicular cells to accumulate radioactive iodide (RAI). DTC generally has a good prognosis. However, tumor dedifferentiation or defect in certain cell death mechanism occurs in a subset of DTC patients, leading to RAI resistance. Therefore, developing novel therapeutic approaches that enhance RAI sensitivity are still warranted. We found that curcumin, an active ingredient in turmeric with anti-cancer properties, rapidly accumulated in the mitochondria of thyroid cancer cells but not normal epithelial cells. Curcumin treatment triggered mitochondrial membrane depolarization, engulfment of mitochondria within autophagosomes and a robust decrease in mitochondrial mass and proteins, indicating that curcumin selectively induced mitophagy in thyroid cancer cells. In addition, curcumin-induced mitophagic cell death and its synergistic cytotoxic effect with radioiodine could be attenuated by autophagy inhibitor, 3-methyladenine (3-MA). Interestingly, the mechanism of mitophagy-inducing potential of curcumin was its unique mitochondria-targeting property, which induced a burst of SDH activity and excessive ROS production. Our data suggest that curcumin induces mitochondrial dysfunction and triggers lethal mitophagy, which synergizes with radioiodine to kill thyroid cancer cells.

A Non-Coding Variant in SLC15A4 Modulates Enhancer Activity and Lysosomal Deacidification Linked to Lupus Susceptibility

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with a strong genetic basis. Despite the identification of several single nucleotide polymorphisms (SNPs) near the SLC15A4 gene that are significantly associated with SLE across multiple populations, specific causal SNP(s) and molecular mechanisms responsible for disease susceptibility are unknown. To address this gap, we employed bioinformatics, expression quantitative trait loci (eQTLs), and 3D chromatin interaction analysis to nominate a likely functional variant, rs35907548, in an active intronic enhancer of SLC15A4. Through luciferase reporter assays followed by chromatin immunoprecipitation (ChIP)-qPCR, we observed significant allele-specific enhancer effects of rs35907548 in diverse cell lines. The rs35907548 risk allele T is associated with increased regulatory activity and target gene expression, as shown by eQTLs and chromosome conformation capture (3C)-qPCR. The latter revealed long-range chromatin interactions between the rs35907548 enhancer and the promoters of SLC15A4, GLTLD1, and an uncharacterized lncRNA. The enhancer-promoter interactions and expression effects were validated by CRISPR/Cas9 knock-out (KO) of the locus in HL60 promyeloblast cells. KO cells also displayed dramatically dysregulated endolysosomal pH regulation. Together, our data show that the rs35907548 risk allele affects multiple aspects of cellular physiology and may directly contribute to SLE.

New Perspectives on Circulating Ferritin: Its Role in Health and Disease

The diagnosis of iron disturbances usually includes the evaluation of serum parameters. Serum iron is assumed to be entirely bound to transferrin, and transferrin saturation-the ratio between the serum iron concentration and serum transferrin-usually reflects iron availability. Additionally, serum ferritin is commonly used as a surrogate of tissue iron levels. Low serum ferritin values are interpreted as a sign of iron deficiency, and high values are the main indicator of pathological iron overload. However, in situations of inflammation, serum ferritin levels may be very high, independently of tissue iron levels. This presents a particularly puzzling challenge for the clinician evaluating the overall iron status of the patient in the presence of an inflammatory condition. The increase in serum ferritin during inflammation is one of the enigmas regarding iron metabolism. Neither the origin, the mechanism of release, nor the effects of serum ferritin are known. The use of serum ferritin as a biomarker of disease has been rising, and it has become increasingly diverse, but whether or not it contributes to controlling the disease or host pathology, and how it would do it, are important, open questions. These will be discussed here, where we spotlight circulating ferritin and revise the recent clinical and preclinical data regarding its role in health and disease.

Emodin derivative E35 and its combination with autophagy inhibitor against acute myeloid leukemia cells in vitro and in vivo

Acute myeloid leukemia (AML) is an aggressive hematopoietic malignancy with poor prognosis and high recurrence rate. The discovery of more effective therapeutic strategies for AML plays a crucial role. The present work showed that E35, a novel derivative of emodin, significantly inhibited cell proliferation and induced autophagy and apoptosis in AML cells. Treatment with E35 markedly induced Beclin-1, LC3-II, cleaved Caspase-9 and PARP, and suppressed mitogen-activated protein kinase (MAPK) pathway. E35 exposure evoked autophagic activity prior to apoptosis induction, and autophagy inhibition by 3-methyladenine (3-MA) dramatically increased E35-induced apoptosis in both AML cell lines and patient-derived AML cells. Nevertheless, study on AML xenograft model showed that the combination E35 with 3-MA exhibited much more inhibitory effects on leukemia cell growth in vivo. No obvious adverse reactions occurred in the xenograft animals administered E35 alone or its cotreatment with 3-MA. These findings suggest that E35 could exert anti-leukemia effects, and that the combination of E35 and autophagy inhibitor might prove a more highly efficient strategy for AML treatment.

Comprehensive evaluation of cell death-related genes as novel diagnostic biomarkers for breast cancer

Background

Breast cancer (BRCA) ranks first among cancers in terms of incidence and mortality rates in women, primarily owing to metastasis, chemo-resistance, and heterogeneity. To predict long-term prognosis and design novel therapies for BRCA, more sensitive markers need to be explored.

Methods

Data from 1089 BRCA patients were downloaded from TCGA database. Pearson's correlation analysis and univariate and multivariate Cox regression analyses were performed to assess the role of cell death-related genes (CDGs) in predicting BRCA prognosis. Kaplan-Meier survival curves were generated to compare the overall survival in the two subgroups. A nomogram was constructed using risk scores based on the five CDGs and other clinicopathological features. CCK-8, EdU incorporation, and colony formation assays were performed to verify the inhibitory effect of NFKBIA on BRCA cell proliferation. Transwell assay, flow cytometry, and immunohistochemistry analyses were performed to ascertain the biological function of NFKBIA.

Results

Five differentially expressed CDGs were detected among 156 CDGs. The risk score for each patient was then calculated based on the expression levels of the five CDGs. Distinct differences in immune infiltration, expression of immune-oncological targets, mutation status, and half-maximal inhibitory concentration values of some targeted drugs were observed between the high- and low-risk groups. Finally, in vitro cell experiments verified that NFKBIA overexpression suppresses the proliferation and migration of BRCA cells.

Conclusions

Our study revealed that some CDGs, especially NFKBIA, could serve as sensitive markers for predicting the prognosis of patients with BRCA and designing more personalized clinical therapies.

Genetic assessment of pathogenic germline alterations in lysosomal genes among Asian patients with pancreatic ductal adenocarcinoma

BACKGROUND

Lysosomes are closely linked to autophagic activity, which plays a vital role in pancreatic ductal adenocarcinoma (PDAC) biology. The survival of PDAC patients is still poor, and the identification of novel genetic factors for prognosis and treatment is highly required to prevent PDAC-related deaths. This study investigated the germline variants related to lysosomal dysfunction in patients with PDAC and to analyze whether they contribute to the development of PDAC.

METHODS

The germline putative pathogenic variants (PPV) in genes involved in lysosomal storage disease (LSD) was compared between patients with PDAC (n = 418) and healthy controls (n = 845) using targeted panel and whole-exome sequencing. Furthermore, pancreatic organoids from wild-type and KrasG12D mice were used to evaluate the effect of lysosomal dysfunction on PDAC development. RNA sequencing (RNA-seq) analysis was performed with established PDAC patient-derived organoids (PDOs) according to the PPV status.

RESULTS

The PPV in LSD-related genes was higher in patients with PDAC than in healthy controls (8.13 vs. 4.26%, Log2 OR = 1.65, P = 3.08 × 10-3). The PPV carriers of LSD-related genes with PDAC were significantly younger than the non-carriers (mean age 61.5 vs. 65.3 years, P = 0.031). We further studied a variant of the lysosomal enzyme, galactosylceramidase (GALC), which was the most frequently detected LSD variant in our cohort. Autophagolysosomal activity was hampered when GALC was downregulated, which was accompanied by paradoxically elevated autophagic flux. Furthermore, the number of proliferating Ki-67+ cells increased significantly in pancreatic organoids derived from Galc knockout KrasG12D mice. Moreover, GALC PPV carriers tended to show drug resistance in both PDAC cell line and PDAC PDO, and RNA-seq analysis revealed that various metabolism and gene repair pathways were upregulated in PDAC PDOs harboring a GALC variant.

CONCLUSIONS

Genetically defined lysosomal dysfunction is frequently observed in patients with young-onset PDAC. This might contribute to PDAC development by altering metabolism and impairing autophagolysosomal activity, which could be potentially implicated in therapeutic applications for PDAC.

HIF-1α-PPARγ-mTORC1 signaling pathway-mediated autophagy induces inflammatory response in pancreatic cells in rats with hyperlipidemic acute pancreatitis

OBJECTIVE

The incidence of hyperlipidemic acute pancreatitis (HLAP) has rapidly increased in recent years in China. Autophagy has been implicated in the inflammatory response of pancreatic cells in HLAP, but the molecular mechanisms remain unclear.

METHODS

In this study, the role of HIF-1α-PPARγ-mTORC1 pathway-mediated autophagy in the inflammatory response of pancreatic cells and the underlying molecular mechanism were investigated in a rat model of HLAP using immunohistochemistry, ELISA, electron microscopy, and western blot analysis.

RESULTS

The results revealed that autophagy was significantly increased and pancreatic injury was exacerbated in HLAP rats, and the inflammatory response was further exacerbated by treatment with rapamycin but relieved by treatment with 3-MA. Hyperlipidemia induced upregulation of HIF-1α and downregulation of PPARγ, which in turn led to an increase in autophagy and consequently exacerbation of the inflammatory response of pancreatic cells.

CONCLUSIONS

HIF-1α-PPARγ-mTORC1 pathway-mediated autophagy plays a critical role in the inflammatory response of pancreatic cells in HLAP, and interference with the HIF-1α-PPARγ-mTOR pathway can serve as a new strategy for the prevention and treatment of HLAP.

The interaction between autophagy, Helicobacter pylori, and gut microbiota in gastric carcinogenesis

Chronic infection with Helicobacter pylori is the primary risk factor for the development of gastric cancer. Hindering our ability to comprehend the precise role of autophagy during H. pylori infection is the complexity of context-dependent autophagy signaling pathways. Recent and ongoing progress in understanding H. pylori virulence allows new frontiers of research for the crosstalk between autophagy and H. pylori. Novel approaches toward discovering autophagy signaling networks have further revealed their critical influence on the structure of gut microbiota and the metabolome. Here we intend to present a holistic view of the perplexing role of autophagy in H. pylori pathogenesis and carcinogenesis. We also discuss the intermediate role of autophagy in H. pylori-mediated modification of gut inflammatory responses and microbiota structure.

Effect of differential deprivation of nutrients on cellular proliferation, oxidative stress, mitochondrial function, and cell migration in MDA-MB-231, HepG2, and HeLa cells

Cancerous cells display metabolic engineering through enhanced utilization of nutrients to support their increased requirements for proliferation, bioenergetics, biosynthesis, redox homeostasis, and cell signaling. To investigate the extent to which malignant cells rely on glycolysis and glutaminolysis, the effects of differential deprivation of nutrients such as d-glucose, l-glutamine, and pyruvate on proliferation, morphology, cell cycle, oxidative stress, mitochondrial function, autophagic vacuole formation, and migration in MDA-MB-231, HepG2, and HeLa cells were investigated in this study. Cell viability assay,  cell morphology, and ATP assay showed higher dependence of MDA-MB-231 and HepG2 cells on glucose and glutamine, respectively, for cell survival, growth, ATP production, and proliferation, while HeLa cells were equally dependent on both. However, the combination of all three nutrients displayed maximum proliferation. Differential deprivation of glucose in the absence of glutamine resulted in G0/G1 plus G2/M arrest in MDA-MB-231, whereas G0/G1 arrest in HepG2 and S-phase arrest in HeLa cells occurred at 48 h. Although the differential withdrawal of nutrients revealed a varying degree of effect dependent on cell type, nutrient type, nutrient concentrations, and deprivation time, a general trend of increased oxidative stress, loss of mitochondrial membrane potential, and ATP and antioxidant (GSH) depletion led to mitochondrial dysfunction in all three cell lines and inhibition of cell migration in MDA-MB-231 and HeLa cells at 48 h. Extreme deprivation of nutrients formed autophagic vacuoles. Importantly, normal cells (HEK293) remained unaffected under most of the nutrient-deprived conditions examined. This study enhances our understanding of the impact of differential nutrient deprivation on critical characteristics of cancer cells, contributing to the development of metabolism-based effective anticancer strategies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03759-w.