Characterization of MUDENG, a novel anti-apoptotic protein

Gintonin-Enriched Panax ginseng Extract Fraction Sensitizes Renal Carcinoma Cells to TRAIL-Induced Apoptosis through DR4/5 Upregulation

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising chemotherapeutic agent because of its selective apoptotic action on cancer cells. However, resistance to TRAIL-induced apoptosis remains a challenge in many cancers. The gintonin-enriched Panax ginseng extract fraction (GEF) has diverse pharmacological benefits. We explored the combined efficacy of GEF and TRAIL in inducing apoptosis in human renal cell carcinoma (RCC) cells. The effect of GEF treatment on the viability, clonogenic potential, wound healing, and TRAIL-induced apoptotic signaling of RCC cells was studied in vitro. Our investigation revealed that GEF pre-treatment sensitized RCC cells to TRAIL-induced apoptosis, as evidenced by DNA fragmentation and cell proliferation, colony formation, and migration inhibition. This sensitization was linked to the upregulation of death receptors 4 and 5 and alterations in apoptotic protein expression, notably, the decreased expression of the Mu-2-related death-inducing gene, a novel anti-apoptotic protein. Our findings underscore the necessity of caspase activation for GEF/TRAIL-induced apoptosis using the pan-caspase inhibitor Z-VAD-FMK. This study demonstrates that GEF sensitizes human RCC cells to TRAIL-induced apoptosis by upregulating DR4/5 and modulating apoptotic protein expression. These findings suggest a promising strategy for overcoming TRAIL resistance in cancer therapy and highlight the potential of GEF as a valuable adjunct to TRAIL-based treatments.

Cinnamaldehyde-Rich Cinnamon Extract Induces Cell Death in Colon Cancer Cell Lines HCT 116 and HT-29

Cinnamon is a natural spice with a wide range of pharmacological functions, including anti-microbial, antioxidant, and anti-tumor activities. The aim of this study is to investigate the effects of cinnamaldehyde-rich cinnamon extract (CRCE) on the colorectal cancer cell lines HCT 116 and HT-29. The gas chromatography mass spectrometry analysis of a lipophilic extract of cinnamon revealed the dominance of trans-cinnamaldehyde. Cells treated with CRCE (10-60 µg/mL) showed significantly decreased cell viability in a time- and dose-dependent manner. We also observed that cell proliferation and migration capacity were inhibited in CRCE-treated cells. In addition, a remarkable increase in the number of sub-G₁-phase cells was observed with arrest at the G₂ phase by CRCE treatment. CRCE also induced mitochondrial stress, and finally, CRCE treatment resulted in activation of apoptotic proteins Caspase-3, -9, and PARP and decreased levels of mu-2-related death-inducing gene protein expression with BH3-interacting domain death agonist (BID) activation.

Role of adaptin protein complexes in intracellular trafficking and their impact on diseases

Adaptin proteins (APs) play a crucial role in intracellular cell trafficking. The 'classical' role of APs is carried out by AP1‒3, which bind to clathrin, cargo, and accessory proteins. Accordingly, AP1-3 are crucial for both vesicle formation and sorting. All APs consist of four subunits that are indispensable for their functions. In fact, based on studies using cells, model organism knockdown/knock-out, and human variants, each subunit plays crucial roles and contributes to the specificity of each AP. These studies also revealed that the sorting and intracellular trafficking function of AP can exert varying effects on pathology by controlling features such as cell development, signal transduction related to the apoptosis and proliferation pathways in cancer cells, organelle integrity, receptor presentation, and viral infection. Although the roles and functions of AP1‒3 are relatively well studied, the functions of the less abundant and more recently identified APs, AP4 and AP5, are still to be investigated. Further studies on these APs may enable a better understanding and targeting of specific diseases.APs known or suggested locations and functions.

Quercetin-3-Glucoside Extracted from Apple Pomace Induces Cell Cycle Arrest and Apoptosis by Increasing Intracellular ROS Levels

Cervical cancer is a life-threatening disease and the fourth most common cancer among women worldwide. Apple pomace is a multifunctional phenolic compound possessing effective biological activity against cervical cancer cells. This study aimed to investigate the anticancer effects of quercetin-3-glucoside (Q3G) extracted from apple pomace in HeLa cell lines and analyze its molecular mechanisms. High-performance liquid chromatography revealed that Q3G, coumaric acid, phloridzin, quercetin, and phloretin are the major polyphenolic compounds constituting apple pomace. Among them, Q3G possessed the greatest antioxidant and anti-inflammatory effects in vitro and exhibited significant cytotoxic effects in HeLa cells in a dose-and time-dependent manner. Flow cytometric analysis indicated that Q3G induced cell cycle arrest at the S phase in a time-dependent manner by altering cyclin-dependent kinase 2. Moreover, it induced apoptosis via chromosomal DNA degradation and increased reactive oxygen species generation. Furthermore, Q3G treatment altered the apoptosis-associated protein expression in the cells by activating caspase-9/-3, downregulating anti-apoptosis protein B-cell lymphoma (Bcl)-2 expressions and up regulating the pro-apoptotic Bcl-2-associated X protein. BH3-interacting domain death agonist cleavage occurred prior to the degradation of an anti-apoptotic Mu-2-related death-inducing gene involved in cell death signaling. Consequently, apple pomace Q3G holds promise as an anti-inflammatory and anticancer agent for treating cervical cancer.

Spiraeoside extracted from red onion skin ameliorates apoptosis and exerts potent antitumor, antioxidant and enzyme inhibitory effects

Red onion skin waste (ROSW) was analyzed for extraction of naturally occurring 4'-O-glucoside of quercetin, spiraeoside (SPI) with promising biological activities. Reversed-phase high-performance liquid chromatography was used to determine the SPI content in three different solvent extracts of ROSW: water (12.2 mg/g), methanol (27.6 mg/g), and ethanol (32.5 mg/g). The ethanol extract and SPI showed significant radical-scavenging and anti-inflammatory activities. In addition, the anti-cancer effects of SPI on a HeLa cells was investigated. The results indicated that SPI treatment significantly inhibited cell growth, and the dose of 50 μg/mL exhibited the highest anti-cancer activity. SPI inhibited the expression of B-cell lymphoma 2 and BH3-interacting domain-death agonist and promoted apoptosis by activating caspase-9/-3 expression. Notably, SPI inhibited the expression of mu-2-related death-inducing gene, a molecule involved in death receptor-mediated apoptotic signaling. Cyclin-dependent kinase 2-cyclin-E expression was also inhibited after SPI treatment, particularly at the G₂/M checkpoint. Our findings provide novel insights into the apoptotic potential with promising anticancer and enzyme inhibitory effects of ROSW SPI.

The MUDENG Augmentation: A Genesis in Anti-Cancer Therapy?

Despite multitudes of reports on cancer remedies available, we are far from being able to declare that we have arrived at that defining anti-cancer therapy. In recent decades, researchers have been looking into the possibility of enhancing cell death-related signaling pathways in cancer cells using pro-apoptotic proteins. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and Mu-2/AP1M2 domain containing, death-inducing (MUDENG, MuD) have been established for their ability to bring about cell death specifically in cancer cells. Targeted cell death is a very attractive term when it comes to cancer, since most therapies also affect normal cells. In this direction TRAIL has made noteworthy progress. This review briefly sums up what has been done using TRAIL in cancer therapeutics. The importance of MuD and what has been achieved thus far through MuD and the need to widen and concentrate on applicational aspects of MuD has been highlighted. This has been suggested as the future perspective of MuD towards prospective progress in cancer research.

Cytotoxic and apoptotic potential of Phyllodium elegans extracts on human cancer cell lines

The extract of Phyllodium (P.) elegans was investigated for its anti-cancer properties on brain astroglioma cells (U251-MG), colorectal carcinoma cells (HCT116), and malignant melanoma cells (A375). P. elegans methanolic extract (PeME) showed cytotoxicity on all three cancer cell lines tested. The cell viability assay revealed that PeME significantly reduced the viability of these cells. Clear apoptotic features such as cellular morphology, cell shrinkage, and augmentation of dead cells were observed. Flow cytometry and fluorescence staining techniques confirmed the apoptotic property of PeME. In vitro scratch invasion assay showed that cell migration rate was significantly reduced. Fluorescence microscopic studies using 4',6-diamidino-2-phenylindole staining showed early and late signs of apoptosis after PeME treatment. Upon PeME stimulation, activation of caspase-3/-9 and Mu-2-related death-inducing gene (MUDENG, MuD) was observed by western blot analysis. JC-1 staining analysis by flow cytometry showed that PeME depolarized the mitochondria membrane potential (MMP). Collectively, these findings, for the first time, point to the fact that PeME has anti-cancer properties against brain, colon, and skin cancer cell lines by depolarizing the MMP and activating apoptotic signaling through the activation of caspase-3/-9 as well as MuD. This is the first report reporting the anticancer activity of this specific plant extract.[Figure: see text].

BAX is an essential key mediator of AP5M1-induced apoptosis in cervical carcinoma cells

The adaptor-related protein complex 5 subunit mu 1 (AP5M1) is an evolutionally conserved protein with ubiquitous expression in human tissues. However, the major function of AP5M1 in living organisms is unclear owing to few published studies. Here, we demonstrate that AP5M1 is a potent apoptosis-inducing molecule in cervical cancer cells. We also found that AP5M1 upregulated the level of BAX protein, a key pro-apoptotic B cell lymphoma (BCL)-2 family member regulating mitochondrial apoptotic cell death pathway. Moreover, AP5M1 completely lost its apoptotic activity in BAX-knockout or -knockdown cells, indicative of its functional dependence on BAX. Comparative analysis of cervical tissues from patients with cervical carcinoma and non-cancer control revealed a prominent downregulation in AP5M1 expression with a concomitant downregulation in BAX expression; AP5M1 and BAX mRNA expression levels in cervical tissues exhibited a strong positive correlation (r = 0.97). Thus, we identified AP5M1 as a previously unrecognized apoptotic protein that governs BAX expression and revealed the association between AP5M1 and malignancy.

MUDENG Expression Profiling in Cohorts and Brain Tumor Biospecimens to Evaluate Its Role in Cancer

Mu-2-related death-inducing gene (MUDENG, MuD) has been reported to be involved in the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-associated apoptotic pathway of glioblastoma multiforme (GBM) cells; however, its expression level, interactors, and role in tumors are yet to be discovered. To investigate whether MuD expression correlates with cancer progression, we analyzed The Cancer Genome Atlas (TCGA) database using UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA). Differential expression of MuD was detected in 6 and 10 cancer types, respectively. Validation performed using data from the Gene Expression Omnibus database showed that MuD expression is downregulated in KIRC tumor and correlate with higher chance of survival. Upregulation of MuD expression in GBM tumors was detected through GEPIA and high MuD expression correlated with higher survival in proneural GBM, whereas the opposite was observed in classical GBM subtype. GBM biospecimens analysis shows that MuD protein level was upregulated in three of six specimens, whereas mRNA level remained relatively unaltered. Therefore, MuD may exert differential effects according to subtypes, and/or be subjected to post-translational regulation in GBM. Correlation analysis between GBM cohort database and experiments using GBM cell lines revealed its positive effect on regulation of protein phosphatase 2 regulatory subunit B’Epsilon (PPP2R5E) and son of sevenless homolog 2 (SOS2). STRING database analysis indicated that the components of adaptor protein complexes putatively interacted with MuD but showed no correlation in terms of survival of patients with different GBM subtypes. In summary, we analyzed the expression of MuD in publicly available cancer patient data sets, GBM cell lines, and biospecimens to demonstrate its potential role as a biomarker for cancer prognosis and identified its candidate interacting molecules.

Generation of single-chain Fv antibody fragments against Mu-2-related death-inducing gene in Escherichia coli

Mu-2-related death-inducing (MuD) gene is involved in apoptosis in tumor cells. Although we have previously produced mouse monoclonal antibodies (MAbs) that specifically recognize human MuD, the application scope of MuD MAbs was restricted due to their mouse origin. Therefore, we attempted the generation of single-chain variable fragment (scFv) against MuD. The heavy- and light-chain variable region genes from two MuD hybridomas were isolated by PCR and joined by DNA encoding a (Gly₄Ser₁)₃ linker. These scFv fragments were cloned into a phagemid vector and expressed as E-tagged fusion proteins in Escherichia coli HB2151. The reactivity of selected Abs was evaluated using ELISA. Selected MuDscFv Abs specifically recognized human MuD, retaining ~ 50% potency of the parent MAbs. MuDscFv-M3H9 recognized the middle region of MuD, while MuDscFv-C22B3 recognized a broad region. Intracellular expression of MuDscFvs-C22B3 protected cells from TRAIL-induced apoptosis. These MuDscFv Abs may help in the study of intracellular signaling pathway centered on MuD and of drug use target and points.

The graviola impact on human astroglioma cells: functional significance of MUDENG

Graviola (Annona muricate) is a coveted tropical plant that has been found to be effective against many human cancers. Malignant glioblastoma multiformes are the most common and aggressive malignant forms of astrocytoma in the central nervous system. MUDENG (Mu-2-related death-inducing gene, MuD) is involved in cell death signaling. In this study, we investigated the impact of extracts from graviola leaves (from Korea and Africa), fruits and seeds against human astroglioma cells. Interestingly, graviola leaf extract-Korea (GLE-K), graviola leaf extract-Africa (GLE-A) and graviola fruit extract-Africa (GFE-A) exhibited significant cytotoxic effects on the cell proliferation in a dose-dependent manner and altered the MuD expression pattern. Cell cycle analyses revealed that GLE-A and GLE-K triggered no significant induction of apoptosis at concentrations up to 5% in U251-MG cells, while in GLE-K treated cells at 10% concentrations, there were much fewer apoptotic cells (33.64%) compared to those in GLE-A (73.55%) treated cells. In the case of GFE-A treated cells, 5% graviola extract (GE) concentration resulted in predominant cells entering the apoptotic phase (59.31%), whereas almost no significant increase in apoptotic cells was observed in GSE-A treated cells (1.38%) even up to 25% of graviola extract (GE) concentration. While using stable transfectants knock-out (KO)(-)-and overexpressing (OE)-MuD(+), significant and consistent differences in the cell viability (enhanced anti-astroglioma effect of GEs) were observed in KO-MuD(-) cells. This validated the functional consequence of MuD in the anti-astroglioma activity of GEs. Our results confirmed that GFE-A possesses the highest anti-astroglioma activity followed by the leaf extracts (GLE-A/K). This is the first report that highlights the MuD aspect of GEs.

Silver nanoparticle-induced hormesis of astroglioma cells: A Mu-2-related death-inducing protein-orchestrated modus operandi

Hormesis is a dose-response phenomenon that, when applied to nanomaterial-biological interactions, refers to growth stimulation at low doses and growth inhibition at high doses. MUDENG (Mu-2-related death-inducing gene, MuD) is involved in cell death signaling. Astrocytes, the major glial cell type in the central nervous system, are a major source of brain tumors. In this study, we investigated whether silver nanoparticles (AgNPs) induce hormesis in astroglioma cells and the possible involvement of MuD in AgNP-induced hormesis. AgNPs exhibited cytotoxic effects on cell proliferation in a dose-dependent manner and increased MuD expression was observed during AgNP-induced astroglioma hormesis. Studies using MuD-knockout cells and MuD siRNA transfection showed that MuD might influence cell viability upon AgNP treatment. In addition, apoptotic cell population and production of reactive oxygen species in the absence of MuD were significantly increased. The phosphorylation of two mitogen-activated protein kinases, p38 and extracellular signal-regulated kinase (ERK), but not c-Jun N-terminal kinases (JNK), was observed upon AgNP stimulation. In summary, AgNPs at low doses induced hormesis of human astroglioma cells, and MuD and p38/ERK mediators are involved in AgNP-induced astroglioma hormesis, resulting in beneficial effects from the cellular point of view.