The Role of Mitochondrial Dynamics and Mitophagy in Carcinogenesis, Metastasis and Therapy

The Warburg effect: The hacked mitochondrial-nuclear communication in cancer

Mitochondrial-nuclear communication is vital for maintaining cellular homeostasis. This communication begins with mitochondria sensing environmental cues and transmitting signals to the nucleus through the retrograde cascade, involving metabolic signals such as substrates for epigenetic modifications, ATP and AMP levels, calcium flux, etc. These signals inform the nucleus about the cell's metabolic state, remodel epigenome and regulate gene expression, and modulate mitochondrial function and dynamics through the anterograde feedback cascade to control cell fate and physiology. Disruption of this communication can lead to cellular dysfunction and disease progression, particularly in cancer. The Warburg effect is the metabolic hallmark of cancer, characterized by disruption of mitochondrial respiration and increased lactate generation from glycolysis. This metabolic reprogramming rewires retrograde signaling, leading to epigenetic changes and dedifferentiation, further reprogramming mitochondrial function and promoting carcinogenesis. Understanding these processes and their link to tumorigenesis is crucial for uncovering tumorigenesis mechanisms. Therapeutic strategies targeting these disrupted pathways, including metabolic and epigenetic components, provide promising avenues for cancer treatment.

Tertiary amine modification enables triterpene nanoparticles to target the mitochondria and treat glioblastoma via pyroptosis induction

Glioblastoma (GBM), the most common primary brain tumor, lacks effective treatments. Emerging evidence suggests mitochondria as a promising therapeutic target, albeit successfully targeting represents a major challenge. Recently, we discovered a group of triterpenes that can self-assemble into nanoparticles (NPs) for cancer treatment. However, unmodified triterpene NPs lack affinity for mitochondria. In this study, using oleanolic acid (OA) as an example, we demonstrated that tertiary amine modification enabled triterpene NPs to selectively target the mitochondria through interaction with translocase of outer mitochondrial membrane 70 (TOM70) leading to effective killing of GBM cells via pyroptosis. We showed that the NPs could be engineered for preferentially penetrating brain tumors through surface conjugation of iRGD, and treatment with the resulting NPs significantly prolonged the survival of tumor-bearing mice. We found that the efficacy could be further improved by encapsulating lonidamine, a mitochondrial hexokinase inhibitor. Furthermore, the observed mitochondria targeting effect through tertiary amine modification could be extended to other triterpenes, including lupeol and glycyrrhetinic acid. Collectively, this study reveals a novel strategy for targeting the mitochondria through tertiary amine modification of triterpenes, offering a promising avenue for the effective treatment of GBM.

Targeting mitophagy using isoliensinine as a therapeutic strategy for renal cell carcinoma treatment

Renal cell carcinoma (RCC) is a formidable and lethal form of kidney cancer, necessitating the exploration of novel therapeutic options. Isoliensinine, an alkaloid derived from lotus seed embryos, has shown promising anti-cancer properties. However, its mechanistic actions and impact on mitochondrial dynamics remain poorly understood. This research has aimed to investigate the effects of isoliensinine on RCC, as well as its potential involvement in mitophagy and mitochondrial function. In vitro experiments utilizing RCC cell lines (786-O and ACHN) have demonstrated that isoliensinine treatment significantly reduced cell viability. Moreover, isoliensinine induced an increase in cellular and mitochondrial reactive oxygen species (ROS) levels, accompanied by reduced mitochondria membrane potential, indicating an influence on mitochondrial function. Furthermore, MitoTracker staining revealed distinct mitochondrial morphologies, with isoliensinine promoting mitochondrial fission, thus supporting its role in mitochondrial dynamics. Notably, isoliensinine led to a time-dependent upregulation of mitophagy-related proteins, indicative of mitophagy activation. Of particular interest, the addition of MitoTEMPO, a potent mitochondrial ROS scavenger, effectively reversed the isoliensinine-induced upregulation of mitophagy-related protein expression and mitochondrial ROS levels. These combined results provide novel insight into the impact of isoliensinine-induced mitophagy on mitochondrial dynamics in renal carcinoma cells. Overall, the findings from this study highlight isoliensinine as a promising candidate with significant potential for further investigation and eventual clinical application in RCC therapy. Moreover, the modulation of mitochondrial dynamics, mitophagy and ROS levels through the use of isoliensinine further adds to its appeal as a potential therapeutic agent.

Keratin: A potential driver of tumor metastasis

Keratins, as essential components of intermediate filaments in epithelial cells, play a crucial role in maintaining cell structure and function. In various malignant epithelial tumors, abnormal keratin expression is frequently observed and serves not only as a diagnostic marker but also closely correlates with tumor progression. Extensive research has demonstrated that keratins are pivotal in multiple stages of tumor metastasis, including responding to mechanical forces, evading the immune system, reprogramming metabolism, promoting angiogenesis, and resisting apoptosis. Here we emphasize that keratins significantly enhance the migratory and invasive capabilities of tumor cells, making them critical drivers of tumor metastasis. These findings highlight the importance of targeting keratins as a strategic approach to combat tumor metastasis, thereby advancing our understanding of their role in cancer progression and offering new therapeutic opportunities.

Autophagy: a double-edged sword in ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury describes the pathological process wherein tissue damage, initially caused by insufficient blood supply (ischemia), is exacerbated upon the restoration of blood flow (reperfusion). This phenomenon can lead to irreversible tissue damage and is commonly observed in contexts such as cardiac surgery and stroke, where blood supply is temporarily obstructed. During ischemic conditions, the anaerobic metabolism of tissues and organs results in compromised enzyme activity. Subsequent reperfusion exacerbates mitochondrial dysfunction, leading to increased oxidative stress and the accumulation of reactive oxygen species (ROS). This cascade ultimately triggers cell death through mechanisms such as autophagy and mitophagy. Autophagy constitutes a crucial catabolic mechanism within eukaryotic cells, facilitating the degradation and recycling of damaged, aged, or superfluous organelles and proteins via the lysosomal pathway. This process is essential for maintaining cellular homeostasis and adapting to diverse stress conditions. As a cellular self-degradation and clearance mechanism, autophagy exhibits a dualistic function: it can confer protection during the initial phases of cellular injury, yet potentially exacerbate damage in the later stages. This paper aims to elucidate the fundamental mechanisms of autophagy in I/R injury, highlighting its dual role in regulation and its effects on both organ-specific and systemic responses. By comprehending the dual mechanisms of autophagy and their implications for organ function, this study seeks to explore the potential for therapeutic interventions through the modulation of autophagy within clinical settings.

Icarisid Ⅱ modulates mitochondrial dynamics for anti-HBV activity

Introduction

To investigate the potential anti-hepatitis B virus (HBV) activity of Icariside Ⅱ (ICS Ⅱ), and elucidate its underlying mitochondrial dynamics mechanisms.

Methods

The study employed in vivo and in vitro assays to evaluate anti-HBV effects of ICS Ⅱ. An HBV replicating mouse model was established through hydrodynamic injection of pAAV/HBV1.2, the impact of ICS Ⅱ on HBV replication and liver toxicity was assessed. In vitro cell-based assays used HBV-positive HepG2.2.15 cells. Cytotoxicity was determined with CCK-8 assay, while ELISA and qPCR were employed to measure HBsAg, HBeAg, and HBV DNA levels. The livers of ICS II-treated HBV-infected mice were taken for transcriptome sequencing to screen for different genes, and the results were verified by Western Blot. Mitochondrial morphology and dynamics were visualized using confocal imaging and transmission electron microscopy. Key protein expressions related to mitochondrial fission and fusion were analyzed via WB. Intracellular ROS generation was assessed using fluorescence staining.

Results

The study found that ICS Ⅱ exhibited significant anti-HBV effects both in vivo and in vitro. The results of RNA-Seq indicated that ICS Ⅱ modulated the mRNA levels of Fisl, a protein associated with mitochondrial dynamics, during the anti-HBV response. It induced mitochondrial fragmentation and enhanced mitochondrial motility in HBV-positive cells. Notably, key proteins associated with mitochondrial fission and fusion demonstrated alterations favoring fission. Furthermore, ICS Ⅱ effectively reduced ROS production in HBV-positive cells.

Conclusion

ICS Ⅱ exhibits significant anti-HBV potential through its regulation of mitochondrial dynamics and ROS production.

Unveiling the future of cancer stem cell therapy: a narrative exploration of emerging innovations

Cancer stem cells (CSCs), are a critical subpopulation within tumours, and are defined by their capacity for self-renewal, differentiation, and tumour initiation. These unique traits contribute to tumour progression, metastasis, and resistance to conventional treatments like chemotherapy and radiotherapy, often resulting in cancer recurrence and poor patient outcomes. As such, CSCs have become focal points in developing advanced cancer therapies. This review highlights progress in CSC-targeted treatments, including chimeric antigen receptor T-cell (CAR-T) therapy, immunotherapy, molecular targeting, and nanoparticle-based drug delivery systems. Plant-derived compounds and gene-editing technologies, such as clustered regularly interspaced short palindromic repeats (CRISPR), are explored for their potential to enhance precision and minimize side effects. Metabolic pathways integral to CSC survival, such as mitochondrial dynamics, mitophagy (regulated by dynamin-related protein 1 [DRP1] and the PINK1/Parkin pathway), one-carbon metabolism, amino acid metabolism (involving enzymes like glutaminase (GLS) and glutamate dehydrogenase (GDH]), lipid metabolism, and hypoxia-induced metabolic reprogramming mediated by hypoxia-inducible factors (HIF-1α and HIF-2α), are examined as therapeutic targets. The adaptability of CSCs through autophagy, metabolic flexibility, and epigenetic regulation by metabolites like α-ketoglutarate, succinate, and fumarate is discussed. Additionally, extracellular vesicles and nicotinamide adenine dinucleotide (NAD⁺) metabolism are identified as pivotal in redox balance, DNA repair, and epigenetic modifications. Addressing challenges such as tumour heterogeneity, immune evasion, and treatment durability requires interdisciplinary collaboration. Advancing CSC-targeted therapies is essential for overcoming drug resistance and preventing cancer relapse, paving the way for transformative cancer treatments. This review underscores the importance of leveraging innovative technologies and fostering collaboration to revolutionize cancer treatment.

Hypoxia induced mitophagy generates reversible metabolic and redox heterogeneity with transient cell death switch driving tumorigenesis

Tumor hypoxia determines tumor growth, metastasis, drug resistance, and tumor heterogeneity through multiple mechanisms, largely dependent on the extent of hypoxia, further modulated by re-oxygenation events. In order to track the cell fates under hypoxia and re-oxygenation, we have developed a sensor cell for real-time tracking of apoptotic, necrotic, and surviving mitophagy cells under hypoxia and re-oxygenation. The study using this sensor revealed a cell death switch from apoptosis to necrosis by hypoxia-exposed cells under re-oxygenation, where mitophagy plays a key role in acquiring temporally evolving functional phenotypes, including metabolic heterogeneity and mitochondrial redox heterogeneity. RNA transcriptomics also revealed a temporally evolving genomic landscape supporting the complex transcriptional plasticity of cells as a non-genetic adaptive event. Interestingly, cells regained from these distinct stages retained their metastatic potential despite slow growth in animal models. Overall, the study demonstrated that cells acquire distinct functions by tumor hypoxia and re-oxygenation, secondarily acquiring transient functional traits and metabolic heterogeneity governed by cell inherent mitochondrial dynamics. Such cell autonomous temporal alterations in cell states governed by organelle integrity with distinct cell proliferation and apoptosis-necrosis switch may be advantageous for the growing tumor to evolve under complex microenvironmental stress, further contributing to tumorigenesis.

Impact of celastrol on mitochondrial dynamics and proliferation in glioblastoma

BACKGROUND

Targeting mitochondrial dynamics offers promising strategies for treating glioblastoma multiforme. Celastrol has demonstrated therapeutic effects on various cancers, but its impact on mitochondrial dynamics in glioblastoma multiforme remains largely unknown. We studied the effects of Celastrol on mitochondrial dynamics, redox homeostasis, and the proliferation.

METHODS

Mito-Tracker Green staining was conducted on U251, LN229, and U87-MG cells to evaluate the effects of Celastrol on mitochondrial dynamics. The Western blot analysis quantified the expression levels of mitochondrial dynamin, antioxidant enzymes, and cell cycle-related proteins. JC-1 staining was performed to discern mitochondrial membrane potential. Mitochondrial reactive oxygen species were identified using MitoSOX. The proliferative capacity of cells was assessed using Cell Counting Kit-8 analysis, and colony formation assays. Survival analysis was employed to evaluate the therapeutic efficacy of Celastrol in C57BL/6J mice with glioblastoma.

RESULTS

Our findings suggest that Celastrol (1 and 1.5 µM) promotes mitochondrial fission by downregulating the expression of mitofusin-1. A decrease in mitochondrial membrane potential at 1 and 1.5 µM indicates that Celastrol impaired mitochondrial function. Concurrently, an increase in mitochondrial reactive oxygen species and impaired upregulation of antioxidant enzymes were noted at 1.5 µM, indicating that Celastrol led to an imbalance in mitochondrial redox homeostasis. At both 1 and 1.5 µM, cell proliferation was inhibited, which may be related to the decreased expression levels of Cyclin-dependent kinase 1 and Cyclin B1. Celastrol extended the survival of GBM-afflicted mice.

CONCLUSION

Celastrol promotes mitochondrial fission in glioblastoma multiforme cells by reducing mitofusin-1 expression, accompanying mitochondrial dysfunction, lower mitochondrial membrane potential, heightened oxidative stress, and decreased Cyclin-dependent kinase 1 and Cyclin B1 levels. This indicates that Celastrol possesses potential for repurposing as an agent targeting mitochondrial dynamics in glioblastoma multiforme, warranting further investigation.

Mitochondrial dysfunction route as a possible biomarker and therapy target for human cancer

Mitochondria are vital organelles found within living cells and have signalling, biosynthetic, and bioenergetic functions. Mitochondria play a crucial role in metabolic reprogramming, which is a characteristic of cancer cells and allows them to ensure a steady supply of proteins, nucleotides, and lipids to enable rapid proliferation and development. Their dysregulated activities have been associated with the growth and metastasis of different kinds of human cancer, particularly ovarian carcinoma. In this review, we briefly demonstrated the modified mitochondrial function in cancer, including mutations in mitochondrial DNA (mtDNA), reactive oxygen species (ROS) production, dynamics, apoptosis of cells, autophagy, and calcium excess to maintain cancer genesis, progression, and metastasis. Furthermore, the mitochondrial dysfunction pathway for some genomic, proteomic, and metabolomics modifications in ovarian cancer has been studied. Additionally, ovarian cancer has been linked to targeted therapies and biomarkers found through various alteration processes underlying mitochondrial dysfunction, notably targeting (ROS), metabolites, rewind metabolic pathways, and chemo-resistant ovarian carcinoma cells.

Research progress of mitochondria and cytoskeleton crosstalk in tumour development

During tumour progression, organelle function undergoes dramatic changes, and crosstalk among organelles plays a significant role. Crosstalk between mitochondria and other organelles such as the endoplasmic reticulum and cytoskeleton has focussed attention on the mechanisms of tumourigenesis. This review demonstrates an overview of the molecular structure of the mitochondrial-cytoskeletal junction and its biological interactions. It also presents a detailed and comprehensive description of mitochondrial-cytoskeletal crosstalk in tumour occurrence and development, including tumour cell proliferation, apoptosis, autophagy, metabolic rearrangement, and metastasis. Finally, the application of crosstalk in tumour therapy, including drug combinations and chemoresistance, is discussed. This review offers a theoretical basis for establishing mitochondrial-cytoskeletal junctions as therapeutic targets, and offers novel insights into the future management of malignant tumours.

Transcriptome profiling and metabolic pathway analysis towards reliable biomarker discovery in early-stage lung cancer

Earlier diagnosis of lung cancer is crucial for reducing mortality and morbidity in high-risk patients. Liquid biopsy is a critical technique for detecting the cancer earlier and tracking the treatment outcomes. However, noninvasive biomarkers are desperately needed due to the lack of therapeutic sensitivity and early-stage diagnosis. Therefore, we have utilized transcriptomic profiling of early-stage lung cancer patients to discover promising biomarkers and their associated metabolic functions. Initially, PCA highlights the diversity level of gene expression in three stages of lung cancer samples. We have identified two major clusters consisting of highly variant genes among the three stages. Further, a total of 7742, 6611, and 643 genes were identified as DGE for stages I-III respectively. Topological analysis of the protein-protein interaction network resulted in seven candidate biomarkers such as JUN, LYN, PTK2, UBC, HSP90AA1, TP53, and UBB cumulatively for the three stages of lung cancers. Gene enrichment and KEGG pathway analyses aid in the comprehension of pathway mechanisms and regulation of identified hub genes in lung cancer. Importantly, the medial survival rates up to ~ 70 months were identified for hub genes during the Kaplan-Meier survival analysis. Moreover, the hub genes displayed the significance of risk factors during gene expression analysis using TIMER2.0 analysis. Therefore, we have reason that these biomarkers may serve as a prospective targeting candidate with higher treatment efficacy in early-stage lung cancer patients.

DARS2 Promotes Bladder Cancer Progression by Enhancing PINK1-Mediated Mitophagy

Globally, bladder cancer is the tenth most common cancer. Mitophagy, a critical process regulating mitochondrial quantity and quality, has attracted increasing attention for its pivotal function in cancer. Nonetheless, its roles and underlying mechanisms in bladder cancer are yet to be elucidated. Therefore, in this study, 16 mitophagy-related genes were screened to construct a robust prognostic model with exceptional predictive accuracy for the outcomes of patients with bladder cancer. Of these genes, DARS2 was identified as a key regulator that significantly affected cancer progression. The findings established that DARS2 promoted the G1-to-S phase transition by upregulating CDK4 expression, thereby suppressing cellular senescence and driving cell proliferation. In addition, DARS2 augmented PINK1 expression, leading to increased PINK1-mediated mitophagy. Both in vitro and in vivo experiments confirmed that DARS2 inhibited cellular senescence and facilitated tumor progression by enhancing PINK1-mediated mitophagy. The observations from this study have provided novel insights into the multifaceted roles of DARS2-mediated mitophagy in bladder cancer. Targeting DARS2 and its regulation of mitophagy is a promising therapeutic strategy to improve the outcomes for patients with bladder cancer.

Identification of mitophagy-related key genes and their correlation with immune cell infiltration in acute myocardial infarction via bioinformatics analysis

Background

Acute myocardial infarction (AMI), a subset of acute coronary syndrome, remains the major cause of mortality worldwide. Mitochondrial dysfunction is critically involved in AMI progression, and mitophagy plays a vital role in eliminating damaged mitochondria. This study aimed to explore mitophagy-related biomarkers and their potential molecular basis in AMI.

Methods

AMI datasets (GSE24519 and GSE34198) from the Gene Expression Omnibus database were combined and the batch effects were removed. Differentially expressed genes (DEGs) in AMI were selected, intersected with mitophagy-related genes for mitophagy-related DEGs (MRDEGs), and then subjected to enrichment analyses. Next, the MRDEGs were screened using machine learning methods (logistic regression analysis, RandomForest, least absolute shrinkage and selection operator) to construct a diagnostic risk model and select the key genes in AMI. The diagnostic efficacy of the model was evaluated using a nomogram. Moreover, the infiltration patterns of different immune cells in two risk groups were compared. We also explored the interactions between the key genes themselves or with miRNAs/transcription factors (TFs) and drug compounds and visualized the protein structure of the key genes. Finally, we explored and validated the expression of key genes in plasma samples of patients with an AMI and healthy individuals.

Results

We screened 28 MRDEGs in AMI. Based on machine learning methods, 12 key genes were screened for the diagnostic risk model, including AGPS, CA2, CAT, LTA4H, MYO9B, PRDX6, PYGB, SIRT3, TFEB, TOM1, UBA52, and UBB. The nomogram further revealed the accuracy of the model for AMI diagnosis. Moreover, we found a lower abundance of immune cells such as gamma delta T and natural killer cells in the high-risk group, and the expression of key genes showed a significant correlation with immune infiltration levels in both groups. Finally, 64 miRNA-mRNA pairs, 75 TF-mRNA pairs, 119 RNA-binding protein-mRNA pairs, and 32 drug-mRNA pairs were obtained in the interaction networks.

Conclusions

In total, 12 key MRDEGs were identified and a risk model was constructed for AMI diagnosis. The findings of this study might provide novel biomarkers for improving the detection of AMI.

Mitochondria's Role in the Maintenance of Cancer Stem Cells in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the predominant form of liver cancer and is recognized as a major contributor to cancer-related mortality worldwide. Cancer stem cells (CSCs) are a tiny group of cancer cells that possess a significant ability to regenerate themselves, form tumors, and undergo differentiation. CSCs have a pivotal role in the initiation, spread, recurrence, and resistance to treatment of cancer. As a result, they are very susceptible to being targeted for therapeutic intervention. The potential to cure HCC may be achieved by efficiently targeting drugs that eradicate cancer stem cells. Mitochondria have a crucial function in granting drug resistance to cancer stem cells by means of mitochondrial metabolism, biogenesis, and dynamics. Dysfunction in mitochondrial metabolic processes, such as mitochondrial oxidative phosphorylation (OXPHOS), calcium signaling, and reactive oxygen species (ROS) generation, contributes to the initiation and progression of human malignancies, including HCC. ROS have both beneficial and detrimental effects depending on their concentration. Consequently, ROS have become a prominent subject in the study of the fundamental mechanisms of HCC. Furthermore, an imbalance in the process of creating new mitochondria is a characteristic feature of CSCs, and an increase in mitochondrial biogenesis is associated with the heightened resistance observed in CSCs. This article provides a detailed examination of the involvement of mitochondria in the preservation of CSCs, as well as the spread of HCC. A deeper understanding of how mitochondria participate in tumorigenesis and drug resistance could result in the discovery of novel cancer treatments.

Facts, Dogmas, and Unknowns About Mitochondrial Reactive Oxygen Species in Cancer

Cancer metabolism is sustained both by enhanced aerobic glycolysis, characteristic of the Warburg phenotype, and oxidative metabolism. Cell survival and proliferation depends on a dynamic equilibrium between mitochondrial function and glycolysis, which is heterogeneous between tumors and even within the same tumor. During oxidative phosphorylation, electrons from NADH and FADH2 originated in the tricarboxylic acid cycle flow through complexes of the electron transport chain. Single electron leaks at specific complexes of the electron transport chain generate reactive oxygen species (ROS). ROS are a concentration-dependent double-edged sword that plays multifaceted roles in cancer metabolism. ROS serve either as signaling molecules favoring cellular homeostasis and proliferation or damage DNA, protein and lipids, causing cell death. Several aspects of ROS biology still remain unsolved. Among the unknowns are the actual levels at which ROS become cytotoxic and if toxicity depends on specific ROS species or if it is caused by a cumulative effect of all of them. In this review, we describe mechanisms of mitochondrial ROS production, detoxification, ROS-induced cytotoxicity, and the use of antioxidants in cancer treatment. We also provide updated information about critical questions on the biology of ROS on cancer metabolism and discuss dogmas that lack adequate experimental demonstration. Overall, this review brings a comprehensive perspective of ROS as drivers of cancer progression, inducers of cell death, and the potential use of antioxidants as anticancer therapy.

The role of mitochondria in tumor metastasis and advances in mitochondria-targeted cancer therapy

Mitochondria are central actors in diverse physiological phenomena ranging from energy metabolism to stress signaling and immune modulation. Accumulating scientific evidence points to the critical involvement of specific mitochondrial-associated events, including mitochondrial quality control, intercellular mitochondrial transfer, and mitochondrial genetics, in potentiating the metastatic cascade of neoplastic cells. Furthermore, numerous recent studies have consistently emphasized the highly significant role mitochondria play in coordinating the regulation of tumor-infiltrating immune cells and immunotherapeutic interventions. This review provides a comprehensive and rigorous scholarly investigation of this subject matter, exploring the intricate mechanisms by which mitochondria contribute to tumor metastasis and examining the progress of mitochondria-targeted cancer therapies.

Spautin-1 promotes PINK1-PRKN-dependent mitophagy and improves associative learning capability in an alzheimer disease animal model

Spautin-1 is a well-known macroautophagy/autophagy inhibitor via suppressing the deubiquitinases USP10 and USP13 and promoting the degradation of the PIK3C3/VPS34-BECN1 complex, while its effect on selective autophagy remains poorly understood. Mitophagy is a selective form of autophagy for removal of damaged and superfluous mitochondria via the autophagy-lysosome pathway. Here, we report a surprising discovery that, while spautin-1 remains as an effective autophagy inhibitor, it promotes PINK1-PRKN-dependent mitophagy induced by mitochondrial damage agents. Mechanistically, spautin-1 facilitates the stabilization and activation of the full-length PINK1 at the outer mitochondrial membrane (OMM) via binding to components of the TOMM complex (TOMM70 and TOMM20), leading to the disruption of the mitochondrial import of PINK1 and prevention of PARL-mediated PINK1 cleavage. Moreover, spautin-1 induces neuronal mitophagy in Caenorhabditis elegans (C. elegans) in a PINK-1-PDR-1-dependent manner. Functionally, spautin-1 is capable of improving associative learning capability in an Alzheimer disease (AD) C. elegans model. In summary, we report a novel function of spautin-1 in promoting mitophagy via the PINK1-PRKN pathway. As deficiency of mitophagy is closely implicated in the pathogenesis of neurodegenerative disorders, the pro-mitophagy function of spautin-1 might suggest its therapeutic potential in neurodegenerative disorders such as AD.Abbreviations: AD, Alzheimer disease; ATG, autophagy related; BafA1, bafilomycin A1; CALCOCO2/NDP52, calcium binding and coiled-coil domain 2; CCCP, carbonyl cyanide m-chlorophenyl hydrazone; COX4/COX IV, cytochrome c oxidase subunit 4; EBSS, Earle's balanced salt; ECAR, extracellular acidification rate; GFP, green fluorescent protein; IA, isoamyl alcohol; IMM, inner mitochondrial membrane; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; MMP, mitochondrial membrane potential; mtDNA, mitochondrial DNA; nDNA, nuclear DNA; O/A, oligomycin-antimycin; OCR, oxygen consumption rate; OMM, outer mitochondrial membrane; OPTN, optineurin; PARL, presenilin associated rhomboid like; PINK1, PTEN induced kinase 1; PRKN, parkin RBR E3 ubiquitin protein ligase; p-Ser65-Ub, phosphorylation of Ub at Ser65; TIMM23, translocase of inner mitochondrial membrane 23; TOMM, translocase of outer mitochondrial membrane; USP10, ubiquitin specific peptidase 10; USP13, ubiquitin specific peptidase 13; VAL, valinomycin; YFP, yellow fluorescent protein.

Targeting mitochondrial dynamics: an in-silico approach for repurposing antifungal drugs in OSCC treatment

Drug repurposing for cancer treatment is a valuable strategy to identify existing drugs with known safety profiles that could combat the neoplasm, by reducing costs. Oral squamous cell carcinoma, an ulcer-proliferative lesion on the mucosal epithelium, is the most common oral malignancy. About 10% of cancer patients within the Indian subcontinent suffer from OSCC, primarily due to chewing of betel plant derivatives. Concomitant administration of the chemotherapeutic agent (Cisplatin/Paclitaxel) is the treatment of choice. Analysis of the oral mycobiome of OSCC patients has projected the role of Candida albicans in potentiating OSCC. Hence, repurposing antifungal drugs emerges as a promising approach, as these drugs could target both the cancer cells and the infection. Cancer cells often have heightened energy requirements, and targeting mitochondrial proteins to disrupt mitochondrial division and induce dysfunction contributing to cell death, offers a method for treating OSCC. We identified 18 mitochondrial targets playing a crucial role in the maintenance of mitochondrial homeostasis. They were docked against 125 antifungal ligand molecules sourced from PUBCHEM. Ligand profiling was performed using Lipinski's rule of 5, SwissADME and ProTox. Also, molecular dynamics and MM-PBSA were performed to validate our results. Among all protein ligand interactions, we observed that targeting DRP1 with itraconazole yielded superior binding and stability. Overall, lower toxicity and thumping ADME properties solidified the choice of ligand. We hope this experimental approach will enable us to provide a basis for selecting a lead molecule for a possible novel nano-formulation and validate our finding through in-vitro cell line-based testing.

Investigating the role of prognostic mitophagy-related genes in non-small cell cancer pathogenesis via multiomics and network-based approach

As one of the most prevalent malignancies, lung cancer displays considerable biological variability in both molecular and clinical characteristics. Lung cancer is broadly categorized into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) with the latter being most prevalent. The primary histological subtypes of NSCLC are lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). In the present work, we primarily extracted mRNA count data from a publicly accessible database followed by differentially expressed genes (DEGs) and differentially expressed mitophagy-related genes (DEMRGs) identification in case of both LUAD and LUSC cohorts. Next, we identified important DEMRGs via clustering approach followed by enrichment, survival, and mutational analyses. Lastly, the finalized prognostic biomarker was validated using wet-lab experimentations. Primarily, we obtained 986 and 1714 DEGs across LUAD and LUSC cohorts. Only 7 DEMRGs from both cohorts had significant membership values as indicated by the clustering analysis. Most significant pathway, Gene Ontology (GO)-biological process (BP), GO-molecular function (MF), GO-cellular compartment (CC) terms were macroautophagy, GTP metabolic process, magnesium ion binding, mitochondrial outer membrane. Among all, only TDRKH reported significant overall survival (OS) and 14% amplification across LUAD patients. Lastly, we validated TDRKH via immunohistochemistry (IHC) and semi-quantitative polymerase chain reaction (PCR). In conclusion, our findings advocate for the exploration of TDRKH and their genetic alterations in precision oncology therapeutic approaches for LUAD, emphasizing the potential for target-driven therapy and early diagnostics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04127-y.

The dual role of autophagy in suppressing and promoting hepatocellular carcinoma

The 5-year survival rate for hepatocellular carcinoma (HCC), a deadly form of liver cancer, is quite low. Although drug therapy is successful, patients with advanced liver cancer frequently develop resistance because of the significant phenotypic and genetic heterogeneity of these cells. The overexpression of drug efflux transporters, downstream adaptive responses, malfunctioning DNA damage repair, epigenetic modification, the tumor microenvironment, and the extracellular matrix can all be linked to drug resistance. The evolutionary process of autophagy, which is in charge of intracellular breakdown, is intimately linked to medication resistance in HCC. Autophagy is involved in both the promotion and suppression of cancer by influencing treatment resistance, metastasis, carcinogenesis, and the viability of stem cells. Certain autophagy regulators are employed in anticancer treatment; however, because of the dual functions of autophagy, their use is restricted, and therapeutic failure is increased. By focusing on autophagy, it is possible to reduce HCC expansion and metastasis, and enhance tumor cell reactivity to treatment. Macroautophagy, the best-characterized type of autophagy, involves the formation of a sequestering compartment termed a phagophore, which surrounds and encloses aberrant or superfluous components. The phagophore matures into a double-membrane autophagosome that delivers the cargo to the lysosome; lysosomes and autophagosomes fuse to degrade and recycle the cargo. Macroautophagy plays dual functions in both promoting and suppressing cancer in a variety of cancer types.

Characterizing mitochondrial features in osteoarthritis through integrative multi-omics and machine learning analysis

Purpose

Osteoarthritis (OA) stands as the most prevalent joint disorder. Mitochondrial dysfunction has been linked to the pathogenesis of OA. The main goal of this study is to uncover the pivotal role of mitochondria in the mechanisms driving OA development.

Materials and methods

We acquired seven bulk RNA-seq datasets from the Gene Expression Omnibus (GEO) database and examined the expression levels of differentially expressed genes related to mitochondria in OA. We utilized single-sample gene set enrichment analysis (ssGSEA), gene set enrichment analysis (GSEA), and weighted gene co-expression network analysis (WGCNA) analyses to explore the functional mechanisms associated with these genes. Seven machine learning algorithms were utilized to identify hub mitochondria-related genes and develop a predictive model. Further analyses included pathway enrichment, immune infiltration, gene-disease relationships, and mRNA-miRNA network construction based on these hub mitochondria-related genes. genome-wide association studies (GWAS) analysis was performed using the Gene Atlas database. GSEA, gene set variation analysis (GSVA), protein pathway analysis, and WGCNA were employed to investigate relevant pathways in subtypes. The Harmonizome database was employed to analyze the expression of hub mitochondria-related genes across various human tissues. Single-cell data analysis was conducted to examine patterns of gene expression distribution and pseudo-temporal changes. Additionally, The real-time polymerase chain reaction (RT-PCR) was used to validate the expression of these hub mitochondria-related genes.

Results

In OA, the mitochondria-related pathway was significantly activated. Nine hub mitochondria-related genes (SIRT4, DNAJC15, NFS1, FKBP8, SLC25A37, CARS2, MTHFD2, ETFDH, and PDK4) were identified. They constructed predictive models with good ability to predict OA. These genes are primarily associated with macrophages. Unsupervised consensus clustering identified two mitochondria-associated isoforms that are primarily associated with metabolism. Single-cell analysis showed that they were all expressed in single cells and varied with cell differentiation. RT-PCR showed that they were all significantly expressed in OA.

Conclusion

SIRT4, DNAJC15, NFS1, FKBP8, SLC25A37, CARS2, MTHFD2, ETFDH, and PDK4 are potential mitochondrial target genes for studying OA. The classification of mitochondria-associated isoforms could help to personalize treatment for OA patients.

Mitochondrial dysfunction significantly contributes to the sensitivity of tumor cells to anoikis and their metastatic potential

It is well-known that the survival of metastatic cells during their dissemination plays an important role in metastasis. However, does this mean that the final result of the metastatic cascade (the volume of metastatic damage to distant organs and tissues) depends on, or at least correlates with, the degree of resistance to anoikis (distinctive hallmarks of metastatic cells)? This question remains open.The aim of the work was to study in vitro the changes in the survival rates, proliferative activity, oxidative stress, and glycolysis intensity during three days of anchorage-dependent and anchorage-independent growth of two Lewis lung carcinoma cell lines (LLC and LLC/R9) and compare these changes with the status of mitochondria and metastatic potential of the cells in vivo.

Methods

The number and volume of lung metastases were estimated for each cell line after intramuscular inoculation of the cells in C57Bl/6 mice. For the in vitro study, the cells were seeded on Petri dishes pretreated with poly-HEMA or untreated dishes and then allowed to grow for 3 days. Cell viability, cell cycle progression, the level of reactive oxygen species (ROS), glucose consumption and lactate production rates were investigated daily in both growth conditions. An electron microscopy study of intracellular structures was carried out.

Results

The study showed (as far as we know for the first time) a correlation between the metastatic potential of cells (determined in vivo) and their sensitivity to anoikis (assessed in vitro). The transition of LLC/R9 cells with an inherently defective mitochondrial system to the conditions of anchorage-independent growth was characterized by a decrease in survival, a slowdown in growth rates, an increase in both glucose consumption rate and intracellular ROS levels and manyfold lower metastatic potential, compared to highly metastatic LLC cells with the normal mitochondrial system.

TRIM21-mediated ubiquitylation of TAT suppresses liver metastasis in gallbladder cancer

Liver metastasis is common in patients with gallbladder cancer (GBC), imposing a significant challenge in clinical management and serving as a poor prognostic indicator. However, the mechanisms underlying liver metastasis remain largely unknown. Here, we report a crucial role of tyrosine aminotransferase (TAT) in liver metastasis of GBC. TAT is frequently up-regulated in GBC tissues. Increased TAT expression is associated with frequent liver metastasis and poor prognosis of GBC patients. Overexpression of TAT promotes GBC cell migration and invasion in vitro, as well as liver metastasis in vivo. TAT knockdown has the opposite effects. Intriguingly, TAT promotes liver metastasis of GBC by potentiating cardiolipin-dependent mitophagy. Mechanistically, TAT directly binds to cardiolipin and leads to cardiolipin externalization and subsequent mitophagy. Moreover, TRIM21 (Tripartite Motif Containing 21), an E3 ubiquitin ligase, interacts with TAT. The histine residues 336 and 338 at TRIM21 are essential for this binding. TRIM21 preferentially adds the lysine 63 (K63)-linked ubiquitin chains on TAT principally at K136. TRIM21-mediated TAT ubiquitination impairs its dimerization and mitochondrial location, subsequently inhibiting tumor invasion and migration of GBC cells. Therefore, our study identifies TAT as a novel driver of GBC liver metastasis, emphasizing its potential as a therapeutic target.

Exploring Importance and Regulation of Autophagy in Cancer Stem Cells and Stem Cell-Based Therapies

Autophagy is a globally conserved cellular activity that plays a critical role in maintaining cellular homeostasis through the breakdown and recycling of cellular constituents. In recent years, there has been much emphasis given to its complex role in cancer stem cells (CSCs) and stem cell treatment. This study examines the molecular processes that support autophagy and how it is regulated in the context of CSCs and stem cell treatment. Although autophagy plays a dual role in the management of CSCs, affecting their removal as well as their maintenance, the intricate interaction between the several signaling channels that control cellular survival and death as part of the molecular mechanism of autophagy has not been well elucidated. Given that CSCs have a role in the development, progression, and resistance to treatment of tumors, it is imperative to comprehend their biological activities. CSCs are important for cancer biology because they also show a tissue regeneration model that helps with organoid regeneration. In other words, the manipulation of autophagy is a viable therapeutic approach in the treatment of cancer and stem cell therapy. Both synthetic and natural substances that target autophagy pathways have demonstrated promise in improving stem cell-based therapies and eliminating CSCs. Nevertheless, there are difficulties associated with the limitations of autophagy in CSC regulation, including resistance mechanisms and off-target effects. Thus, the regulation of autophagy offers a versatile strategy for focusing on CSCs and enhancing the results of stem cell therapy. Therefore, understanding the complex interactions between autophagy and CSC biology would be essential for creating therapeutic treatments that work in both regenerative medicine and cancer treatment.

P53/NANOG balance; the leading switch between poorly to well differentiated status in liver cancer cells

Enforcing a well-differentiated state on cells requires tumor suppressor p53 activation as a key player in apoptosis induction and well differentiation. In addition, recent investigations showed a significant correlation between poorly differentiated status and higher expression of NANOG. Inducing the expression of NANOG and decreasing p53 level switch the status of liver cancer cells from well differentiated to poorly status. In this review, we highlighted p53 and NANOG cross-talk in hepatocellular carcinoma (HCC) which is regulated through mitophagy and makes it a novel molecular target to attenuate cancerous phenotype in the management of this tumor.

Chinese botanical drugs targeting mitophagy to alleviate diabetic kidney disease, a comprehensive review

Diabetic kidney disease (DKD) is one of the chronic microvascular complications caused by diabetes, which is characterized by persistent albuminuria and/or progressive decline of estimated glomerular filtration rate (eGFR), and has been the major cause of dialysis around the world. At present, although the treatments for DKD including lifestyle modification, glycemic control and even using of Sodium-glucose cotransporter 2 (SGLT2) inhibitors can relieve kidney damage caused to a certain extent, there is still a lack of effective treatment schemes that can prevent DKD progressing to ESRD. It is urgent to find new complementary and effective therapeutic agents. Growing animal researches have shown that mitophagy makes a great difference to the pathogenesis of DKD, therefore, exploration of new drugs that target the restoration of mitophagy maybe a potential perspective treatment for DKD. The use of Chinese botanical drugs (CBD) has been identified to be an effective treatment option for DKD. There is growing concern on the molecular mechanism of CBD for treatment of DKD by regulating mitophagy. In this review, we highlight the current findings regarding the function of mitophagy in the pathological damages and progression of DKD and summarize the contributions of CBD that ameliorate renal injuries in DKD by interfering with mitophagy, which will help us further explain the mechanism of CBD in treatment for DKD and explore potential therapeutic strategies for DKD.

OMA1 competitively binds to HSPA9 to promote mitophagy and activate the cGAS-STING pathway to mediate GBM immune escape

BACKGROUND

Immunotherapy with checkpoint inhibitors, especially those targeting programmed death receptor 1 (PD-1)/PD-1 ligand (PD-L1), is increasingly recognized as a highly promising therapeutic modality for malignancies. Nevertheless, the efficiency of immune checkpoint blockade therapy in treating glioblastoma (GBM) is constrained. Hence, it is imperative to expand our comprehension of the molecular mechanisms behind GBM immune escape (IE).

METHODS

Protein chip analysis was performed to screen aberrantly expressed OMA1 protein in PD-1 inhibitor sensitive or resistant GBM. Herein, public databases and bioinformatics analysis were employed to investigate the OMA1 and PD-L1 relation. Then, this predicted relation was verified in primary GBM cell lines through distinct experimental methods. To investigate the molecular mechanism behind OMA1 in immunosuppression, a series of experimental methods were employed, including Western blotting, co-immunoprecipitation (Co-IP), mass spectrometry (MS), immunofluorescence, immunohistochemistry, and qRT-PCR.

RESULTS

Our findings revealed that OMA1 competitively binds to HSPA9 to induce mitophagy and mediates the IE of GBM. Data from TCGA indicated a significant correlation between OMA1 and immunosuppression. OMA1 promoted PD-L1 levels in primary cells from patients with GBM. Next, the results of Co-IP and MS conducted on GBM primary cells revealed that OMA1 interacts with HSPA9 and induces mitophagy. OMA1 promoted not only cGAS-STING activity by increasing mitochondrial DNA release but also PD-L1 transcription by activating cGAS-STING. Eventually, OMA1 has been found to induce immune evasion in GBM through its regulation of PD-1 binding and PD-L1 mediated T cell cytotoxicity.

CONCLUSIONS

The OMA1/HSPA9/cGAS/PD-L1 axis is elucidated in our study as a newly identified immune therapeutic target in GBM.

Mitochondrial Mechanisms in Temozolomide Resistance: Unraveling the Complex Interplay and Therapeutic Strategies in Glioblastoma

Glioblastoma (GBM) is a highly aggressive and lethal brain tumor, with temozolomide (TMZ) being the standard chemotherapeutic agent for its treatment. However, TMZ resistance often develops, limiting its therapeutic efficacy and contributing to poor patient outcomes. Recent evidence highlights the crucial role of mitochondria in the development of TMZ resistance through various mechanisms, including alterations in reactive oxygen species (ROS) production, metabolic reprogramming, apoptosis regulation, biogenesis, dynamics, stress response, and mtDNA mutations. This review article aims to provide a comprehensive overview of the mitochondrial mechanisms involved in TMZ resistance and discuss potential therapeutic strategies targeting these mechanisms to overcome resistance in GBM. We explore the current state of clinical trials targeting mitochondria or related pathways in primary GBM or recurrent GBM, as well as the challenges and future perspectives in this field. Understanding the complex interplay between mitochondria and TMZ resistance will facilitate the development of more effective therapeutic strategies and ultimately improve the prognosis for GBM patients.

Mitochondrion: Main organelle in orchestrating cancer escape from chemotherapy

BACKGROUND

Chemoresistance is a challenging barrier to cancer therapy, and in this context, the role of mitochondria is significant. We put emphasis on key biological characteristics of mitochondria, contributing to tumor escape from various therapies, to find the "Achilles' Heel" of cancer cells for future drug design.

RECENT FINDINGS

The mitochondrion is a dynamic organelle, and its existence is important for tumor growth. Its metabolites also cooperate with cell signaling in tumor proliferation and drug resistance.

CONCLUSION

Biological characteristics of this organelle, such as redox balance, DNA depletion, and metabolic reprogramming, provide flexibility to cancer cells to cope with therapy-induced stress.

Mitochondria act as a key regulatory factor in cancer progression: Current concepts on mutations, mitochondrial dynamics, and therapeutic approach

The diversified impacts of mitochondrial function vs. dysfunction have been observed in almost all disease conditions including cancers. Mitochondria play crucial roles in cellular homeostasis and integrity, however, mitochondrial dysfunctions influenced by alterations in the mtDNA can disrupt cellular balance. Many external stimuli or cellular defects that cause cellular integrity abnormalities, also impact mitochondrial functions. Imbalances in mitochondrial activity can initiate and lead to accumulations of genetic mutations and can promote the processes of tumorigenesis, progression, and survival. This comprehensive review summarizes epigenetic and genetic alterations that affect the functionality of the mitochondria, with considerations of cellular metabolism, and as influenced by ethnicity. We have also reviewed recent insights regarding mitochondrial dynamics, miRNAs, exosomes that play pivotal roles in cancer promotion, and the impact of mitochondrial dynamics on immune cell mechanisms. The review also summarizes recent therapeutic approaches targeting mitochondria in anti-cancer treatment strategies.

Comprehensive analysis of mitophagy-related genes in NSCLC diagnosis and immune scenery: based on bulk and single-cell RNA sequencing data

Lung cancer is the main cause of cancer-related deaths, and non-small cell lung cancer (NSCLC) is the most common type. Understanding the potential mechanisms, prognosis, and treatment aspects of NSCLC is essential. This study systematically analyzed the correlation between mitophagy and NSCLC. Six mitophagy-related feature genes (SRC, UBB, PINK1, FUNDC1, MAP1LC3B, and CSNK2A1) were selected through machine learning and used to construct a diagnostic model for NSCLC. These feature genes are closely associated with the occurrence and development of NSCLC. Additionally, NSCLC was divided into two subtypes using unsupervised consensus clustering, and their differences in clinical characteristics, immune infiltration, and immunotherapy were systematically analyzed. Furthermore, the interaction between mitophagy-related genes (MRGs) and immune cells was analyzed using single-cell sequencing data. The findings of this study will contribute to the development of potential diagnostic biomarkers for NSCLC and the advancement of personalized treatment strategies.

DRP1: At the Crossroads of Dysregulated Mitochondrial Dynamics and Altered Cell Signaling in Cancer Cells

In the past decade, compelling evidence has accumulated that highlights the role of various subcellular structures in human disease conditions. Dysregulation of these structures greatly impacts cellular function and, thereby, disease conditions. One such organelle extensively studied for its role in several human diseases, especially cancer, is the mitochondrion. DRP1 is a GTPase that is considered the master regulator of mitochondrial fission and thereby also affects the proper functioning of the organelle. Altered signaling pathways are a distinguished characteristic of cancer cells. In this review, we aim to summarize our current understanding of the interesting crosstalk between the mitochondrial structure-function maintained by DRP1 and the signaling pathways that are affected in cancer cells. We highlight the structural aspects of DRP1, its regulation by various modifications, and the association of the protein with various cellular pathways altered in cancer. A better understanding of this association may help in identifying potential pharmacological targets for novel therapies in cancer.

Prognostic and immune correlation analysis of mitochondrial autophagy and aging-related genes in lung adenocarcinoma

PURPOSE

Mitophagy and aging (MiAg) are very important pathophysiological mechanisms contributing to tumorigenesis. MiAg-related genes have prognostic value in lung adenocarcinoma (LUAD). However, prognostic, and immune correlation studies of MiAg-related genes in LUAD are lacking.

METHODS

MiAg differentially expressed genes (DEGs) in LUAD were obtained from public sequencing datasets. A prognostic model including MiAg DEGs was constructed according to patients divided into low- and high-risk groups. Gene Ontology, gene set enrichment analysis, gene set variation analysis, CIBERSORT immune infiltration analysis, and clinical characteristic correlation analyses were performed for functional annotation and correlation of MiAgs with prognosis in patients with LUAD.

RESULTS

Seven MiAg DEGs of LUAD were identified: CAV1, DSG2, DSP, MYH11, NME1, PAICS, PLOD2, and the expression levels of these genes were significantly correlated (P < 0.05). The RiskScore of the MiAg DEG prognostic model demonstrated high predictive ability of overall survival of patients diagnosed with LUAD. Patients with high and low MiAg phenotypic scores exhibited significant differences in the infiltration levels of eight types of immune cells (P < 0.05). The multi-factor DEG regression model showed higher efficacy in predicting 5-year survival than 3- and 1-year survival of patients with LUAD.

CONCLUSIONS

Seven MiAg-related genes were identified to be significantly associated with the prognosis of patients diagnosed with LUAD. Moreover, the identified MiAg DEGs might affect the immunotherapy strategy of patients with LUAD.

PTEN-induced kinase 1 gene single-nucleotide variants as biomarkers in adjuvant chemotherapy for colorectal cancer: a retrospective study

BACKGROUND

Fluoropyrimidine-based postoperative adjuvant chemotherapy is globally recommended for high-risk stage II and stage III colon cancer. However, adjuvant chemotherapy is often associated with severe adverse events and is not highly effective in preventing recurrence. Therefore, discovery of novel molecular biomarkers of postoperative adjuvant chemotherapy to identify patients at increased risk of recurrent colorectal cancer is warranted. Autophagy (including mitophagy) is activated under chemotherapy-induced stress and contributes to chemotherapy resistance. Expression of autophagy-related genes and their single-nucleotide polymorphisms are reported to be effective predictors of chemotherapy response in some cancers. Our goal was to evaluate the relationship between single-nucleotide variants of autophagy-related genes and recurrence rates in order to identify novel biomarkers that predict the effect of adjuvant chemotherapy in colorectal cancer.

METHODS

We analyzed surgical or biopsy specimens from 84 patients who underwent radical surgery followed by fluoropyrimidine-based adjuvant chemotherapy at Saitama Medical University International Medical Center between January and December 2016. Using targeted enrichment sequencing, we identified single-nucleotide variants and insertions/deletions in 50 genes, including autophagy-related genes, and examined their association with colorectal cancer recurrence rates.

RESULTS

We detected 560 single-nucleotide variants and insertions/deletions in the target region. The results of Fisher's exact test indicated that the recurrence rate of colorectal cancer after adjuvant chemotherapy was significantly lower in patients with the single-nucleotide variants (c.1018G > A [p < 0.005] or c.1562A > C [p < 0.01]) of the mitophagy-related gene PTEN-induced kinase 1.

CONCLUSIONS

The two single-nucleotide variants of PINK1 gene may be biomarkers of non-recurrence in colorectal cancer patients who received postoperative adjuvant chemotherapy.

Mitochondrial dysfunction at the crossroad of cardiovascular diseases and cancer

A large body of evidence indicates the existence of a complex pathophysiological relationship between cardiovascular diseases and cancer. Mitochondria are crucial organelles whose optimal activity is determined by quality control systems, which regulate critical cellular events, ranging from intermediary metabolism and calcium signaling to mitochondrial dynamics, cell death and mitophagy. Emerging data indicate that impaired mitochondrial quality control drives myocardial dysfunction occurring in several heart diseases, including cardiac hypertrophy, myocardial infarction, ischaemia/reperfusion damage and metabolic cardiomyopathies. On the other hand, diverse human cancers also dysregulate mitochondrial quality control to promote their initiation and progression, suggesting that modulating mitochondrial homeostasis may represent a promising therapeutic strategy both in cardiology and oncology. In this review, first we briefly introduce the physiological mechanisms underlying the mitochondrial quality control system, and then summarize the current understanding about the impact of dysregulated mitochondrial functions in cardiovascular diseases and cancer. We also discuss key mitochondrial mechanisms underlying the increased risk of cardiovascular complications secondary to the main current anticancer strategies, highlighting the potential of strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction and tumorigenesis. It is hoped that this summary can provide novel insights into precision medicine approaches to reduce cardiovascular and cancer morbidities and mortalities.

Identifying mitophagy-related genes as prognostic biomarkers and therapeutic targets of gastric carcinoma by integrated analysis of single-cell and bulk-RNA sequencing data

Gastric carcinoma (GC) is the fourth leading cause of cancer-related mortality worldwide. Patients with advanced GC tend to have poor prognoses and shortened survival. Finding novel predictive biomarkers for GC prognosis is an urgent need. Mitophagy is the selection degradation of damaged mitochondria to maintain cellular homeostasis, which has been shown to play both pro- and anti-tumor effects. This study combined single-cell sequencing data and transcriptomics to screen mitophagy-related genes (MRGs) associated with GC progression and analyze their clinical values. Reverse transcription-quantitative PCR (RT-qPCR) and immunochemistry (IHC) further verified gene expression profiles. A total of 18 DE-MRGs were identified after taking an intersection of single-cell sequencing data and MRGs. Cells with a higher MRG score were mainly distributed in the epithelial cell cluster. Cell-to-cell communications among epithelial cells with other cell types were significantly upregulated. We established and validated a reliable nomogram model based on DE-MRGs (GABARAPL2 and CDC37) and traditional clinicopathological parameters. GABARAPL2 and CDC37 displayed different immune infiltration states. Given the significant correlation between hub genes and immune checkpoints, targeting MRGs in GC may supplement more benefits to patients who received immunotherapy. In conclusion, GABARAPL2 and CDC37 may be prognostic biomarkers and candidate therapeutic targets of GC.

Investigation of PRKN Mutations in Levodopa-Induced Dyskinesia in Parkinson's Disease Treatment

Mitophagy is an important process that participates in mitochondrial quality control. Dysfunctions in this process can be caused by mutations in genes like PRKN and are associated with the development and progression of Parkinson's Disease (PD). The most used drug in the treatment of PD is levodopa (LD), but it can cause adverse effects, such as dyskinesia. Currently, few studies are searching for biomarkers for an effective use of lLD for this disease, especially regarding mitophagy genetics. Thus, this work investigates the association of 14 variants of the PRKN gene with LD in the treatment of PD. We recruited 70 patients with PD undergoing treatment with LD (39 without dyskinesia and 31 with dyskinesia). Genotyping was based on Sanger sequencing. Our results reinforce that age at onset of symptoms, duration of PD, and treatment and dosage of LD can influence the occurrence of dyskinesia but not the investigated PRKN variants. The perspective presented here of variants of mitophagy-related genes in the context of treatment with LD is still underexplored, although an association has been indicated in previous studies. We suggest that other variants in PRKN or in other mitophagy genes may participate in the development of levodopa-induced dyskinesia in PD treatment.

GPD1L inhibits renal cell carcinoma progression by regulating PINK1/Parkin-mediated mitophagy

Few approaches have been conducted in the treatment of renal cell carcinoma (RCC) after nephrectomy, resulting in a high mortality rate in urological tumours. Mitophagy is a mechanism of mitochondrial quality control that enables selective degradation of damaged and unnecessary mitochondria. Previous studies have found that glycerol-3-phosphate dehydrogenase 1-like (GPD1L) is associated with the progression of tumours such as lung cancer, colorectal cancer and oropharyngeal cancer, but the potential mechanism in RCC is still unclear. In this study, microarrays from tumour databases were analysed. The expression of GPD1L was confirmed by RT-qPCR and western blotting. The effect and mechanism of GPD1L were explored using cell counting kit 8, wound healing, invasion, flow cytometry and mitophagy-related experiments. The role of GPD1L was further confirmed in vivo. The results showed that GPD1L expression was downregulated and positively correlated with prognosis in RCC. Functional experiments revealed that GPD1L prevented proliferation, migration and invasion while promoting apoptosis and mitochondrial injury in vitro. The mechanistic results indicated that GPD1L interacted with PINK1, promoting PINK1/Parkin-mediated mitophagy. However, inhibition of PINK1 reversed GPD1L-mediated mitochondrial injury and mitophagy. Moreover, GPD1L prevented tumour growth and promoted mitophagy by activating the PINK1/Parkin pathway in vivo. Our study shows that GPD1L has a positive correlation with the prognosis of RCC. The potential mechanism involves interacting with PINK1 and regulating the PINK1/Parkin pathway. In conclusion, these results reveal that GPD1L can act as a biomarker and target for RCC diagnosis and therapy.

Integrating Multi-Omics Analysis for Enhanced Diagnosis and Treatment of Glioblastoma: A Comprehensive Data-Driven Approach

The most aggressive primary malignant brain tumor in adults is glioblastoma (GBM), which has poor overall survival (OS). There is a high relapse rate among patients with GBM despite maximally safe surgery, radiation therapy, temozolomide (TMZ), and aggressive treatment. Hence, there is an urgent and unmet clinical need for new approaches to managing GBM. The current study identified modules (MYC, EGFR, PIK3CA, SUZ12, and SPRK2) involved in GBM disease through the NeDRex plugin. Furthermore, hub genes were identified in a comprehensive interaction network containing 7560 proteins related to GBM disease and 3860 proteins associated with signaling pathways involved in GBM. By integrating the results of the analyses mentioned above and again performing centrality analysis, eleven key genes involved in GBM disease were identified. ProteomicsDB and Gliovis databases were used for determining the gene expression in normal and tumor brain tissue. The NetworkAnalyst and the mGWAS-Explorer tools identified miRNAs, SNPs, and metabolites associated with these 11 genes. Moreover, a literature review of recent studies revealed other lists of metabolites related to GBM disease. The enrichment analysis of identified genes, miRNAs, and metabolites associated with GBM disease was performed using ExpressAnalyst, miEAA, and MetaboAnalyst tools. Further investigation of metabolite roles in GBM was performed using pathway, joint pathway, and network analyses. The results of this study allowed us to identify 11 genes (UBC, HDAC1, CTNNB1, TRIM28, CSNK2A1, RBBP4, TP53, APP, DAB1, PINK1, and RELN), five miRNAs (hsa-mir-221-3p, hsa-mir-30a-5p, hsa-mir-15a-5p, hsa-mir-130a-3p, and hsa-let-7b-5p), six metabolites (HDL, N6-acetyl-L-lysine, cholesterol, formate, N, N-dimethylglycine/xylose, and X2. piperidinone) and 15 distinct signaling pathways that play an indispensable role in GBM disease development. The identified top genes, miRNAs, and metabolite signatures can be targeted to establish early diagnostic methods and plan personalized GBM treatment strategies.

Aryl hydrocarbon receptor maintains hepatic mitochondrial homeostasis in mice

OBJECTIVE

Mitophagy removes damaged mitochondria to maintain cellular homeostasis. Aryl hydrocarbon receptor (AhR) expression in the liver plays a crucial role in supporting normal liver functions, but its impact on mitochondrial function is unclear. Here, we identified a new role of AhR in the regulation of mitophagy to control hepatic energy homeostasis.

METHODS

In this study, we utilized primary hepatocytes from AhR knockout (KO) mice and AhR knockdown AML12 hepatocytes. An endogenous AhR ligand, kynurenine (Kyn), was used to activate AhR in AML12 hepatocytes. Mitochondrial function and mitophagy process were comprehensively assessed by MitoSOX and mt-Keima fluorescence imaging, Seahorse XF-based oxygen consumption rate measurement, and Mitoplate S-1 mitochondrial substrate utilization analysis.

RESULTS

Transcriptomic analysis indicated that mitochondria-related gene sets were dysregulated in AhR KO liver. In both primary mouse hepatocytes and AML12 hepatocyte cell lines, AhR inhibition strongly suppressed mitochondrial respiration rate and substrate utilization. AhR inhibition also blunted the fasting response of several essential autophagy genes and the mitophagy process. We further identified BCL2 interacting protein 3 (BNIP3), a mitophagy receptor that senses nutrient stress, as an AhR target gene. AhR is directly recruited to the Bnip3 genomic locus, and Bnip3 transcription was enhanced by AhR endogenous ligand treatment in wild-type liver and abolished entirely in AhR KO liver. Mechanistically, overexpression of Bnip3 in AhR knockdown cells mitigated the production of mitochondrial reactive oxygen species (ROS) and restored functional mitophagy.

CONCLUSIONS

AhR regulation of the mitophagy receptor BNIP3 coordinates hepatic mitochondrial function. Loss of AhR induces mitochondrial ROS production and impairs mitochondrial respiration. These findings provide new insight into how endogenous AhR governs hepatic mitochondrial homeostasis.

Role of Macroautophagy in Mammalian Male Reproductive Physiology

Physiologically, autophagy is an evolutionarily conserved and self-degradative process in cells. Autophagy carries out normal physiological roles throughout mammalian life. Accumulating evidence shows autophagy as a mechanism for cellular growth, development, differentiation, survival, and homeostasis. In male reproductive systems, normal spermatogenesis and steroidogenesis need a balance between degradation and energy supply to preserve cellular metabolic homeostasis. The main process of autophagy includes the formation and maturation of the phagophore, autophagosome, and autolysosome. Autophagy is controlled by a group of autophagy-related genes that form the core machinery of autophagy. Three types of autophagy mechanisms have been discovered in mammalian cells: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy is classified as non-selective or selective. Non-selective macroautophagy randomly engulfs the cytoplasmic components in autophagosomes that are degraded by lysosomal enzymes. While selective macroautophagy precisely identifies and degrades a specific element, current findings have shown the novel functional roles of autophagy in male reproduction. It has been recognized that dysfunction in the autophagy process can be associated with male infertility. Overall, this review provides an overview of the cellular and molecular basics of autophagy and summarizes the latest findings on the key role of autophagy in mammalian male reproductive physiology.

MitoTNT: Mitochondrial Temporal Network Tracking for 4D live-cell fluorescence microscopy data

Mitochondria form a network in the cell that rapidly changes through fission, fusion, and motility. Dysregulation of this four-dimensional (4D: x,y,z,time) network is implicated in numerous diseases ranging from cancer to neurodegeneration. While lattice light-sheet microscopy has recently made it possible to image mitochondria in 4D, quantitative analysis methods for the resulting datasets have been lacking. Here we present MitoTNT, the first-in-class software for Mitochondrial Temporal Network Tracking in 4D live-cell fluorescence microscopy data. MitoTNT uses spatial proximity and network topology to compute an optimal tracking assignment. To validate the accuracy of tracking, we created a reaction-diffusion simulation to model mitochondrial network motion and remodeling events. We found that our tracking is >90% accurate for ground-truth simulations and agrees well with published motility results for experimental data. We used MitoTNT to quantify 4D mitochondrial networks from human induced pluripotent stem cells. First, we characterized sub-fragment motility and analyzed network branch motion patterns. We revealed that the skeleton node motion is correlated along branch nodes and is uncorrelated in time. Second, we identified fission and fusion events with high spatiotemporal resolution. We found that mitochondrial skeleton nodes near the fission/fusion sites move nearly twice as fast as random skeleton nodes and that microtubules play a role in mediating selective fission/fusion. Finally, we developed graph-based transport simulations that model how material would distribute on experimentally measured mitochondrial temporal networks. We showed that pharmacological perturbations increase network reachability but decrease network resilience through a combination of altered mitochondrial fission/fusion dynamics and motility. MitoTNT's easy-to-use tracking module, interactive 4D visualization capability, and powerful post-tracking analyses aim at making temporal network tracking accessible to the wider mitochondria research community.

Emerging mechanistic insights of selective autophagy in hepatic diseases

Macroautophagy (hereafter referred to as autophagy), a highly conserved metabolic process, regulates cellular homeostasis by degrading dysfunctional cytosolic constituents and invading pathogens via the lysosomal system. In addition, autophagy selectively recycles specific organelles such as damaged mitochondria (via mitophagy), and lipid droplets (LDs; via lipophagy) or eliminates specialized intracellular pathogenic microorganisms such as hepatitis B virus (HBV) and coronaviruses (via virophagy). Selective autophagy, particularly mitophagy, plays a key role in the preservation of healthy liver physiology, and its dysfunction is connected to the pathogenesis of a wide variety of liver diseases. For example, lipophagy has emerged as a defensive mechanism against chronic liver diseases. There is a prominent role for mitophagy and lipophagy in hepatic pathologies including non-alcoholic fatty liver disease (NAFLD), hepatocellular carcinoma (HCC), and drug-induced liver injury. Moreover, these selective autophagy pathways including virophagy are being investigated in the context of viral hepatitis and, more recently, the coronavirus disease 2019 (COVID-19)-associated hepatic pathologies. The interplay between diverse types of selective autophagy and its impact on liver diseases is briefly addressed. Thus, modulating selective autophagy (e.g., mitophagy) would seem to be effective in improving liver diseases. Considering the prominence of selective autophagy in liver physiology, this review summarizes the current understanding of the molecular mechanisms and functions of selective autophagy (mainly mitophagy and lipophagy) in liver physiology and pathophysiology. This may help in finding therapeutic interventions targeting hepatic diseases via manipulation of selective autophagy.

The FDX1 methylation regulatory mechanism in the malignant phenotype of glioma

To explore FDX1 methylation as a regulatory mechanism in the malignant phenotype of glioma, we screened for pathways involved through bioinformatic analysis, then proceeded with RIP and cell models to verify the regulation of RNAs and mitophagy. We chose Clone and Transwell assays to evaluate the malignant phenotype of glioma cells. MMP was detected by flow cytometry and mitochondrial morphology was observed by TEM. We also constructed animal models to study the sensitivity of glioma cells to cuproptosis. We successfully identified the signalling pathway: our cell model showed that C-MYC could upregulate FDX1 through YTHDF1 and inhibit mitophagy in glioma cells. Functional experiments revealed C-MYC could also enhance glioma cell proliferation and invasion via YTHDF1 and FDX1. In vivo experiments showed glioma cells were highly sensitive to cuproptosis. We concluded that C-MYC could upregulate FDX1 by m6A methylation, thus promoting the malignant phenotype in glioma cells.

Non-Coding RNA-Dependent Regulation of Mitochondrial Dynamics in Cancer Pathophysiology

Mitochondria are essential organelles which dynamically change their shape and number to adapt to various environmental signals in diverse physio-pathological contexts. Mitochondrial dynamics refers to the delicate balance between mitochondrial fission (or fragmentation) and fusion, that plays a pivotal role in maintaining mitochondrial homeostasis and quality control, impinging on other mitochondrial processes such as metabolism, apoptosis, mitophagy, and autophagy. In this review, we will discuss how dysregulated mitochondrial dynamics can affect different cancer hallmarks, significantly impacting tumor growth, survival, invasion, and chemoresistance. Special emphasis will be given to emerging non-coding RNA molecules targeting the main fusion/fission effectors, acting as novel relevant upstream regulators of the mitochondrial dynamics rheostat in a wide range of tumors.

Autophagy/Mitophagy Regulated by Ubiquitination: A Promising Pathway in Cancer Therapeutics

Autophagy is essential for organismal development, maintenance of energy homeostasis, and quality control of organelles and proteins. As a selective form of autophagy, mitophagy is necessary for effectively eliminating dysfunctional mitochondria. Both autophagy and mitophagy are linked with tumor progression and inhibition. The regulation of mitophagy and autophagy depend upon tumor type and stage. In tumors, mitophagy has dual roles: it removes damaged mitochondria to maintain healthy mitochondria and energy production, which are necessary for tumor growth. In contrast, mitophagy has been shown to inhibit tumor growth by mitigating excessive ROS production, thus preventing mutation and chromosomal instability. Ubiquitination and deubiquitination are important modifications that regulate autophagy. Multiple E3 ubiquitin ligases and DUBs modulate the activity of the autophagy and mitophagy machinery, thereby influencing cancer progression. In this review, we summarize the mechanistic association between cancer development and autophagy/mitophagy activities regulated by the ubiquitin modification of autophagic proteins. In addition, we discuss the function of multiple proteins involved in autophagy/mitophagy in tumors that may represent potential therapeutic targets.

TRIM27 is an autophagy substrate facilitating mitochondria clustering and mitophagy via phosphorylated TBK1

Tripartite motif-containing protein 27 (TRIM27/also called RFP) is a multifunctional ubiquitin E3 ligase involved in numerous cellular functions, such as proliferation, apoptosis, regulation of the NF-kB pathway, endosomal recycling and the innate immune response. TRIM27 interacts directly with TANK-binding kinase 1 (TBK1) and regulates its stability. TBK1 in complex with autophagy receptors is recruited to ubiquitin chains assembled on the mitochondrial outer membrane promoting mitophagy. Here, we identify TRIM27 as an autophagy substrate, depending on ATG7, ATG9 and autophagy receptors for its lysosomal degradation. We show that TRIM27 forms ubiquitylated cytoplasmic bodies that co-localize with autophagy receptors. Surprisingly, we observed that induced expression of EGFP-TRIM27 in HEK293 FlpIn TRIM27 knockout cells mediates mitochondrial clustering. TRIM27 interacts with autophagy receptor SQSTM1/p62, and the TRIM27-mediated mitochondrial clustering is facilitated by SQSTM/p62. We show that phosphorylated TBK1 is recruited to the clustered mitochondria. Moreover, induced mitophagy activity is reduced in HEK293 FlpIn TRIM27 knockout cells, while re-introduction of EGFP-TRIM27 completely restores the mitophagy activity. Inhibition of TBK1 reduces mitophagy in HEK293 FlpIn cells and in the reconstituted EGFP-TRIM27-expressing cells, but not in HEK293 FlpIn TRIM27 knockout cells. Altogether, these data reveal novel roles for TRIM27 in mitophagy, facilitating mitochondrial clustering via SQSTM1/p62 and mitophagy via stabilization of phosphorylated TBK1 on mitochondria.

The role of metabolic reprogramming in pancreatic cancer chemoresistance

Pancreatic cancer is characterized by hidden onset, high malignancy, and early metastasis. Although a few cases meet the surgical indications, chemotherapy remains the primary treatment, and the resulting chemoresistance has become an urgent clinical problem that needs to be solved. In recent years, the importance of metabolic reprogramming as one of the hallmarks of cancers in tumorigenesis has been validated. Metabolic reprogramming involves glucose, lipid, and amino acid metabolism and interacts with oncogenes to affect the expression of key enzymes and signaling pathways, modifying the tumor microenvironment and contributing to the occurrence of drug tolerance. Meanwhile, the mitochondria are hubs of the three major nutrients and energy metabolisms, which are also involved in the development of drug resistance. In this review, we summarized the characteristic changes in metabolism during the progression of pancreatic cancer and their impact on chemoresistance, outlined the role of the mitochondria, and summarized current studies on metabolic inhibitors.

A Comprehensive Analysis of the Effects of Key Mitophagy Genes on the Progression and Prognosis of Lung Adenocarcinoma

The aim of our study was to perform a comprehensive analysis of the gene expression, copy number variation (CNV) and mutation of key mitophagy genes in the progression and prognosis of lung adenocarcinoma (LUAD). We obtained the data from The Cancer Genome Atlas (TCGA). Clustering analysis was performed to stratify the mitophagy related groups. The least absolute shrinkage and selection operator (LASSO) based cox model was used to select hub survival genes. An independent validation cohort was retrieved from Gene Expression Omnibus database. We found 24 out of 27 mitophagy genes were aberrantly expressed between tumor and normal samples. CNV gains were associated with higher expression of mitophagy genes in 23 of 27 mitophagy genes. The clustering analysis identified high and low risk mitophagy groups with distinct survival differences. The high risk mitophagy groups had higher tumor mutation burden, stemness phenotype, total CNVs and lower CD4+ T cells infiltration. Drugs targeted to high risk mitophagy groups were identified including the PI3K/AKT/mTOR inhibitor, HDAC inhibitor and chemotherapy agents such as cisplatin and gemcitabine. In addition, the differentially expressed genes (DEGs) were identified between mitophagy groups. Further univariate Cox analysis of each DEG and subsequent LASSO-based Cox model revealed a mitophagy-related prognostic signature. The risk score model of this signature showed a strong ability to predict the overall survival of LUAD patients in training and validation datasets. In conclusion, the mitophagy genes played an important role in the progression and prognosis of LUAD, which might provide useful information for the treatment of LUAD.