PARK2 promotes mitochondrial pathway of apoptosis and antimicrotubule drugs chemosensitivity via degradation of phospho-BCL-2

Microtubules and cardiovascular diseases: insights into pathology and therapeutic strategies

Microtubules, complex cytoskeletal structures composed of tubulin proteins in eukaryotic cells, have garnered recent attention in cardiovascular research. Investigations have focused on the post-translational modifications of tubulin, including acetylation and detyrosination. Perturbations in microtubule homeostasis have been implicated in various pathological processes associated with cardiovascular diseases such as heart failure, ischemic heart disease, and arrhythmias. Thus, elucidating the intricate interplay between microtubule dynamics and cardiovascular pathophysiology is imperative for advancing preventive and therapeutic strategies. Several natural compounds have been identified to potentially modulate microtubules, thereby exerting regulatory effects on cardiovascular diseases. This review synthesizes current literature to delineate the roles of microtubules in cardiovascular diseases and assesses the potential of natural compounds in microtubule-targeted therapies.

Increased CCT5 expression is a potential unfavourable factor promoting the growth of nasopharyngeal carcinoma

OBJECTIVE

Chaperonin containing TCP1 subunit 5 (CCT5) encodes the CCT5 protein subunit of chaperonin-containing TCP-1 (CCT/TRiC) complex, and is shown to be upregulated in tumour pathogenesis. The study aim was to investigate the differential expression of CCT5 between nasopharyngeal carcinoma (NPC) and noncancerous nasopharyngeal tissues, and the correlation between CCT5 expression and clinicopathological parameters/prognosis in patients with NPC.

METHODS

Microarray assay data were evaluated for differential expression between NPC and noncancerous nasopharyngeal tissues. CCT5 expression in NPC and noncancerous nasopharyngeal tissues was determined at mRNA and protein levels by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. Relationships between CCT5 expression in NPC, clinical parameters, and prognosis were statistically analysed. CCT5-mediated cell proliferation was assessed using EdU and cell counting kit-8. Western blot and co-immunoprecipitation were utilized to explore E3 ubiquitin-protein ligase parkin (PARK2)-induced degradation of CCT5.

RESULTS

Microarray data showed CCT5 levels to be significantly increased in NPC versus noncancerous nasopharyngeal tissues, which was confirmed by qRT-PCR and immunohistochemical assays. Increased CCT5 protein levels positively correlated with tumour size, tumour recurrence, and clinical stage, and inversely correlated with patient's overall survival. Multivariate Cox regression analysis showed that enhanced CCT5 protein expression is an independent prognostic factor for patients with NPC. Overexpression of CCT5 markedly induced NPC cell proliferation. Finally, PARK2, as a suppressive E3 ubiquitin-ligase enzyme, was shown to bind CCT5 and induce degradation in NPC.

CONCLUSIONS

Increased CCT5 may be an unfavourable factor promoting NPC growth. Binding of PARK2 to CCT5 was associated with CCT5 degradation, suggesting that PARK2 is an upstream negative modulator in NPC.

Decoding cell death signalling: Impact on the response of breast cancer cells to approved therapies

Breast cancer is a principal cause of cancer-related mortality in female worldwide. While many approved therapies have shown promising outcomes in treating breast cancer, understanding the intricate signalling pathways controlling cell death is crucial for optimizing the treatment outcome. A growing body of evidence has unveiled the aberrations in multiple cell death pathways across diverse cancer types, highlighting these pathways as appealing targets for therapeutic interventions. In this review, we provide a comprehensive overview of the current state of knowledge on the cell death signalling mechanisms with a particular focus on their impact on the response of breast cancer cells to approved therapies. Additionally, we discuss the potentials of combination therapies that exploit the synergy between approved drugs and therapeutic agents targeting modulators of cell death pathways.

Parkin inhibits proliferation and migration of bladder cancer via ubiquitinating Catalase

PRKN is a key gene involved in mitophagy in Parkinson's disease. However, recent studies have demonstrated that it also plays a role in the development and metastasis of several types of cancers, both in a mitophagy-dependent and mitophagy-independent manner. Despite this, the potential effects and underlying mechanisms of Parkin on bladder cancer (BLCA) remain unknown. Therefore, in this study, we investigated the expression of Parkin in various BLCA cohorts derived from human. Here we show that PRKN expression was low and that PRKN acts as a tumor suppressor by inhibiting the proliferation and migration of BLCA cells in a mitophagy-independent manner. We further identified Catalase as a binding partner and substrate of Parkin, which is an important antioxidant enzyme that regulates intracellular ROS levels during cancer progression. Our data showed that knockdown of CAT led to increased intracellular ROS levels, which suppressed cell proliferation and migration. Conversely, upregulation of Catalase decreased intracellular ROS levels, promoting cell growth and migration. Importantly, we found that Parkin upregulation partially restored these effects. Moreover, we discovered that USP30, a known Parkin substrate, could deubiquitinate and stabilize Catalase. Overall, our study reveals a novel function of Parkin and identifies a potential therapeutic target in BLCA.

Contribution and therapeutic value of mitophagy in cerebral ischemia-reperfusion injury after cardiac arrest

Cardiopulmonary resuscitation and related life support technologies have improved substantially in recent years; however, mortality and disability rates from cardiac arrest (CA) remain high and are closely associated with the high incidence of cerebral ischemia-reperfusion injury (CIRI), which is explained by a "double-hit" model (i.e., resulting from both ischemia and reperfusion). Mitochondria are important power plants in the cell and participate in various biochemical processes, such as cell differentiation and signaling in eukaryotes. Various mitochondrial processes, including energy metabolism, calcium homeostasis, free radical production, and apoptosis, are involved in several important stages of the progression and development of CIRI. Mitophagy is a key mechanism of the endogenous removal of damaged mitochondria to maintain organelle function and is a critical target for CIRI treatment after CA. Mitophagy also plays an essential role in attenuating ischemia-reperfusion in other organs, particularly during post-cardiac arrest myocardial dysfunction. Regulation of mitophagy may influence necroptosis (a programmed cell death pathway), which is the main endpoint of organ ischemia-reperfusion injury. In this review, we summarize the main signaling pathways related to mitophagy and their associated regulatory proteins. New therapeutic methods and drugs targeting mitophagy in ischemia-reperfusion animal models are also discussed. In-depth studies of the mechanisms underlying the regulation of mitophagy will enhance our understanding of the damage and repair processes in CIRI after CA, thereby contributing to the development of new therapeutic strategies.

Use of Enzymatically Activated Carbon Monoxide Donors for Sensitizing Drug-Resistant Tumor Cells

The application of gaseous signaling molecules like NO, H₂S or CO to overcome the multidrug resistance in cancer treatment has proven to be a viable therapeutic strategy. The development of CO-releasing molecules (CORMs) in a controlled manner and in targeted tissues remains a challenge in medicinal chemistry. In this paper, we describe the design, synthesis and chemical and enzymatic stability of a novel non-metal CORM (1) able to release intracellularly CO and, simultaneously, facilitate fluorescent degradation of products under the action of esterase. The toxicity of 1 against different human cancer cell lines and their drug-resistant counterparts, as well as the putative mechanism of toxicity were investigated. The drug-resistant cancer cell lines efficiently absorbed 1 and 1 was able to restore their sensitivity vs. chemotherapeutic drugs by causing a CO-dependent mitochondrial oxidative stress that culminated in mitochondrial-dependent apoptosis. These results demonstrate the importance of CORMs in cases where conventional chemotherapy fails and thus open the horizons towards new combinatorial strategies to overcome multidrug resistance.

PINK1-Mediated Mitophagy Promotes Oxidative Phosphorylation and Redox Homeostasis to Induce Drug-Tolerant Persister Cancer Cells

The drug-tolerant persister (DTP) state enables cancer cells to evade cytotoxic stress from anticancer therapy. However, the mechanisms governing DTP generation remain poorly understood. Here, we observed that lung adenocarcinoma (LUAD) cells and organoids entered a quiescent DTP state to survive MAPK inhibitor treatment. DTP cells following MAPK inhibition underwent a metabolic switch from glycolysis to oxidative phosphorylation (OXPHOS). PTEN-induced kinase 1 (PINK1), a serine/threonine kinase that initiates mitophagy, was upregulated to maintain mitochondrial homeostasis during DTP generation. PINK1-mediated mitophagy supported DTP cell survival and contributed to poor prognosis. Mechanistically, MAPK pathway inhibition resulted in MYC-dependent transcriptional upregulation of PINK1, leading to mitophagy activation. Mitophagy inhibition using either clinically applicable chloroquine or depletion of PINK1 eradicated drug tolerance and allowed complete response to MAPK inhibitors. This study uncovers PINK1-mediated mitophagy as a novel tumor protective mechanism for DTP generation, providing a therapeutic opportunity to eradicate DTP and achieve complete responses.

SIGNIFICANCE

DTP cancer cells that cause relapse after anticancer therapy critically depend on PINK1-mediated mitophagy and metabolic reprogramming, providing a therapeutic opportunity to eradicate persister cells to prolong treatment efficacy.

Aspiletrein A Induces Apoptosis Cell Death via Increasing Reactive Oxygen Species Generation and AMPK Activation in Non-Small-Cell Lung Cancer Cells

Lung cancer remains a leading cause of death in cancer patients, and deregulation of apoptosis is a serious concern in clinical practice, even though therapeutic intervention has been greatly improved. Plants are a versatile source of biologically active compounds for anticancer drug discovery, and aspiletrein A (AA) is a steroidal saponin isolated from Aspidistra letreae that has a potent cytotoxic effect on various cancer cell lines. In this study, we investigated and determined the underlying molecular mechanism by which AA induces apoptosis. AA strongly induced apoptosis in NSCLC cells by mediating ROS generation and thereby activating AMP-activated protein kinase (AMPK) signaling. Consequently, downstream signaling and levels of phosphorylated mTOR and Bcl-2 were significantly decreased. Pretreatment with either an antioxidant, N-acetylcysteine, or an AMPK inhibitor, compound C, could reverse the apoptosis-inducing effect and counteract the effect of AA on the AMPK signaling pathway. Decreased levels of Bcl-2 were due to AA-mediating Bcl-2 degradation via a ROS/AMPK/mTOR axis-dependent proteasomal mechanism. Consistently, the apoptotic-inducing effect of AA was also observed in patient-derived malignant lung cancer cells, and it suppressed an in vitro 3D-tumorigenesis. This study identified the underlying mechanism of AA on lung cancer apoptosis, thereby facilitating potential research and development of this compound for further clinical implications.

Copper induces microglia-mediated neuroinflammation through ROS/NF-κB pathway and mitophagy disorder

The epidemiological correlation between copper exposure and higher risk of Parkinson disease (PD) has been recognized for a long time, and microglia-mediated neuroinflammation has reported to be an important component of the pathogenesis of PD. The present study aimed to investigate the role of microglial activation and neuroinflammation in copper neurotoxicity and the underlying mechanism of copper-induced activation of microglia. Based on the inflammatory changes in mouse brain tissues, the activation of microglia, the loss of dopaminergic neurons and the aggregation of α-syn were found in the substantia nigra. In this study we found that copper significantly caused inflammatory activation of BV2 cells. Importantly, copper increased the level of reactive oxygen species (ROS) in BV2 cells, and then activated the NF-κB pathway which acted as an early survival signal. Further study indicated that sustained copper accumulation in BV2 cells led to the decrease of mitochondrial membrane potential, reduction of Parkin and PINK1 expression, increase of P62 expression and LC3BⅡ/I ratio, as well as upregulation of NLRP3/caspase1/GSDMD axis proteins. In addition, the increased release of inflammatory factors was rescued by redox agent, NF-κB pathway inhibitor and mitophagy inducer. This work illustrated that copper exposure activates microglia to secrete inflammatory products, resulting in the pyroptosis of dopaminergic neurons, which was related to the early activation of ROS/NF-κB pathway and subsequent mitophagy disorder in BV2 cells.

Protein interaction networks in neurodegenerative diseases: from physiological function to aggregation

The accumulation of protein inclusions is linked to many neurodegenerative diseases that typically develop in older individuals, due to a combination of genetic and environmental factors. In rare familial neurodegenerative disorders, genes encoding for aggregation-prone proteins are often mutated. While the underlying mechanism leading to these diseases still remains to be fully elucidated, efforts in the past 20 years revealed a vast network of protein–protein interactions that play a major role in regulating the aggregation of key proteins associated with neurodegeneration. Misfolded proteins that can oligomerize and form insoluble aggregates associate with molecular chaperones and other elements of the proteolytic machineries that are the frontline workers attempting to protect the cells by promoting clearance and preventing aggregation. Proteins that are normally bound to aggregation-prone proteins can become sequestered and mislocalized in protein inclusions, leading to their loss of function. In contrast, mutations, posttranslational modifications, or misfolding of aggregation-prone proteins can lead to gain of function by inducing novel or altered protein interactions, which in turn can impact numerous essential cellular processes and organelles, such as vesicle trafficking and the mitochondria. This review examines our current knowledge of protein–protein interactions involving several key aggregation-prone proteins that are associated with Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, or amyotrophic lateral sclerosis. We aim to provide an overview of the protein interaction networks that play a central role in driving or mitigating inclusion formation, while highlighting some of the key proteomic studies that helped to uncover the extent of these networks.

X-Box Binding Protein 1 (XBP1): A Potential Role in Chemotherapy Response, Clinical Pathologic Features, Non-Inflamed Tumour Microenvironment for Breast Cancer

X-box binding protein 1 (XBP1) is mainly expressed in breast cancer (BC) in human cancers. Its tumorigenesis and favourable prognosis are contradictory, and its essential role in chemotherapeutic response and immunosuppression is unknown in BC. The study firstly identified XBP1 who received neoadjuvant chemotherapy (NAC) from GSE25055 and GSE24460. Associations between XBP1 expression and clinicopathological characteristics was investigated using Oncomine, TCGA, UALCAN and bc-GenExMiner. The prognostic value of XBP1 was assessed using the Kaplan–Meier Plotter, bc-GenExMiner, GSE25055, and GSE25056. Furthermore, we systematically correlated XBP1 and immunological characteristics in the BC tumour microenvironment (TME) using TISIDB, TIMER, GSE25055, GSE25056 and TCGA dataset. Finally, an essential role of XBP1 in chemotherapy response was evaluated based on GSE25055, GSE25065, GSE24460, GSE5846, ROC Plotter and CELL databases. Furthermore, XBP1 mRNA expression levels were obviously highest in BC among human cancers and were significantly related to a good prognosis. In addition, XBP1 mRNA and protein levels were higher in the luminal subtype than in normal tissues and basal-like subtype, which might be attributed to membrane transport-related processes. Apart from BC, negative immunological correlations of XBP1 were not observed in other malignancies. XBP1 might shape the non-inflamed TME in BC. Finally, XBP1 expression was higher in chemo-resistive than chemo-sensitive cases, it had a predictive value and could independently predict chemotherapy response in BC patients receiving NAC. Our study suggests that the essential role of XBP1 in clinical pathologic features, non-inflamed TME, chemotherapy response in BC.

Parkin: A targetable linchpin in human malignancies

Parkin, an E3 ubiquitin ligase has been found to be deregulated in a variety of human cancers. Our current understanding is endowed with strong evidences that Parkin plays crucial role in the pathogenesis of cancer by controlling/interfering with major hallmarks of cancer delineated till today. Consistent with the idea of mitophagy, the existing studies imitates the tumor suppressive potential of Parkin, resolved by its capacity to regulate cell proliferation, cell migration, angiogenesis, apoptosis and overall cellular survival. Dysfunction of Parkin has resulted in the loss of ubiquitination of cell cycle components followed by their accumulation leading to genomic instability, perturbed cell cycle and eventually tumor progression. In this review, we provide an overview of current knowledge about the critical role of Parkin in cancer development and progression and have focussed on its therapeutic implications highlighting the diagnostic and prognostic value of Parkin as a biomarker. We earnestly hope that an in-depth knowledge of Parkin will provide a linchpin to target in various cancers that will open a new door of clinical applications and therapeutics.