Expression Of Catalytic Subunit Research Articles

Differential Activity and Expression of Proteasome in Seminiferous Epithelium During Mouse Spermatogenesis.

Proteasome-mediated protein degradation is essential for maintaining cellular homeostasis, particularly during spermatogenesis, where extensive cellular transformations, such as spermatid differentiation, require precise protein turnover. A key player in this process is the ubiquitin-proteasome system (UPS). This study aimed to investigate proteasome enzymatic activity at different stages of the spermatogenic cycle within the seminiferous tubules of mice and explore the regulatory mechanisms that influence its proteolytic function. Specifically, we assessed the trypsin-like, chymotrypsin-like, and peptidyl-glutamyl-peptide-hydrolyzing (PGPH) activities of the proteasome. Additionally, we examined the expression of catalytic and structural subunits of the 20S core, the assembly of the 20S core with regulatory complexes, and the phosphorylation status of proteasome subunits in various segments of the seminiferous tubules. Our findings demonstrated distinct patterns of proteasomal enzymatic activity in the analyzed segments. While the expression levels of structural and catalytic subunits of the 20S core remained consistent, significant differences were detected in the assembly of the 20S core, the expression of regulatory complexes, and the phosphorylation of proteasome subunits mediated by protein kinase A. These results indicate that proteasomal activity is finely regulated through multiple mechanisms depending on the specific stage of the seminiferous epithelial cycle, highlighting the complexity of proteostasis during spermatogenesis.

Arsenic inducible islet β-cell dysfunction and ferroptosis through m6A-YTHDF2-dependent CHAC1 enhancement.

Arsenic, recognized as an environmental and food contaminant, has been linked to the dysfunction of islet β-cells, the primary lesions in type 2 diabetes (T2D). Ferroptosis, a regulated cell death pathway dependent on GPX4, has been implicated in arsenic-induced β-cell dysfunction. However, the underlying molecular mechanisms remain unclear. GPX4 activity is significantly modulated by glutathione levels. In this study, we demonstrate that arsenic inhibits GPX4 expression by upregulating the expression of glutathione-specific γ-glutamylcyclotransferase 1 (CHAC1) (>2-fold in vivo and 1.5-fold in vitro). Conversely, arsenic does not affect the expression of the glutathione-cysteine ligase catalytic subunit (GCLC), which is crucial for glutathione synthesis. Notably, CHAC1 knockdown significantly ameliorated arsenic-induced β-cell dysfunction and ferroptosis. N6-methyladenosine (m6A) plays a crucial role in the post-transcriptional modification of mRNA. Arsenic treatment downregulated the expression of methyltransferases METTL3/14 (approximately 0.5-fold), and overexpression of METTL3 alleviated arsenic-induced β-cell dysfunction and ferroptosis. The m6A modification site on CHAC1 was identified, and RIP assays confirmed that arsenic treatment inhibited the interaction between METTL3/YTHDF2 and CHAC1. Furthermore, METTL3 overexpression reduced the half-life of CHAC1 mRNA (almost 0.5-fold). This study uncovers a novel mechanism by which arsenic modulates CHAC1 and ferroptosis through m6A in β-cell dysfunction, highlighting potential therapeutic targets for arsenic-related T2D.

Deregulation of Casein Kinase-2 in non-small-cell lung cancer: A subunit-specific analysis

Casein kinase-2 (CK2) is a constitutively active kinase that supports neoplastic properties. Although there is an extensive body of preclinical research on CK2, translational and clinical information remains limited and sparse. In this study, we interrogated clinical multiomics databases to examine CK2 deregulation across various cancers. Specifically, we analyzed the mutational frequency, copy-number alterations (CNA), and mRNA expression of CK2 catalytic (CSNK2A1 and CSNK2A2) and regulatory (CSNK2B) subunits across two major cancer genomic repositories (The Cancer Genome Atlas/International Cancer Genome Consortium). These genomic and transcriptomic analyses were further focused on lung cancer and complemented by in situ assessments of CK2 protein subunits and enzymatic activity in biopsies from non-small-cell lung cancer (NSCLC). Our findings indicate that gene mutations and CNA do not account for the elevated mRNA levels and enzymatic activity of CK2 subunits in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). Particularly, the upregulation of CSNK2A1 and CSNK2B mRNA was associated with a worse prognosis and showed a direct correlation with the infiltration of myeloid-derived suppressor cells in LUAD. At the protein levels, all CK2 subunits and enzymatic activity were markedly elevated in LUAD (n = 103) and LUSC (n = 31) biopsies; however, only CSNK2A1 expression correlated positively with tumor size and disease stage. Finally, CSNK2A1 appeared to be more tumor-specific than CSNK2A2, suggesting that targeted therapies against this catalytic subunit or its homotetramer may offer a more favorable therapeutic window in NSCLC.

NFE2L2 and SLC25A39 drive cuproptosis resistance through GSH metabolism

Cuproptosis is a recently discovered form of regulated cell death triggered by mitochondrial copper accumulation and proteotoxic stress. Here, we provide the first evidence that glutathione (GSH), a major non-protein thiol in cells, acts as a cuproptosis inhibitor in pancreatic ductal adenocarcinoma (PDAC) cells. Mechanistically, GSH inhibits cuproptosis by chelating copper, contrasting its role in blocking ferroptosis by inhibiting lipid peroxidation. The classical cuproptosis inducer, ES-Cu (elesclomol plus copper), increases the protein stability of the transcription factor NFE2L2 (also known as NRF2), leading to the upregulation of gene expression of glutamate-cysteine ligase modifier subunit (GCLM) and glutamate-cysteine ligase catalytic subunit (GCLC). GCLM and GCLC are rate-limiting enzymes in GSH synthesis, and increased GSH is transported into mitochondria via the solute carrier family 25 member 39 (SLC25A39) transporter. Consequently, genetic inhibition of the NFE2L2-GSH-SLC25A39 pathway enhances cuproptosis-mediated tumor suppression in cell culture and in mouse tumor models. These findings not only reveal distinct mechanisms of GSH in inhibiting cuproptosis and ferroptosis, but also suggest a potential combination strategy to suppress PDAC tumor growth.

Natural variation in age-related dopamine neuron degeneration is glutathione dependent and linked to life span

Aging is the biggest risk factor for Parkinson's disease (PD), suggesting that age-related changes in the brain promote dopamine neuron vulnerability. It is unclear, however, whether aging alone is sufficient to cause significant dopamine neuron loss, and if so, how this intersects with PD-related neurodegeneration. Here, through examining a large collection of naturally varying Drosophila strains, we find a strong relationship between life span and age-related dopamine neuron loss. Strains with naturally short-lived animals exhibit a loss of dopamine neurons without generalized neurodegeneration, while animals from long-lived strains retain dopamine neurons across age. Metabolomic profiling reveals lower glutathione levels in short-lived strains which is associated with elevated levels of reactive oxygen species (ROS), sensitivity to oxidative stress, and vulnerability to silencing the familial PD gene parkin. Strikingly, boosting neuronal glutathione levels via glutamate-cysteine ligase (Gcl) overexpression is sufficient to normalize ROS levels, extend life span, and block dopamine neurons loss in short-lived backgrounds, demonstrating that glutathione deficiencies are central to neurodegenerative phenotypes associated with short longevity. These findings may be relevant to human PD pathogenesis, where glutathione depletion is reported to occur in the idiopathic PD patient brain through unknown mechanisms. Building on this, we find reduced expression of the Gcl catalytic subunit in both Drosophila strains vulnerable to age-related dopamine neuron loss and in the human brain from familial PD patients harboring the common LRRK2 G2019S mutation. Our study across Drosophila and human PD systems suggests that glutathione synthesis and levels play a conserved role in regulating age-related dopamine neuron health.

LINC00894 Regulates Cerebral Ischemia/Reperfusion Injury by Stabilizing EIF5 and Facilitating ATF4-Mediated Induction of FGF21 and ACOD1 Expression

The non-coding RNA LINC00894 modulates tumor proliferation and drug resistance. However, its role in brain is still unclear. Using RNA-pull down combined with mass spectrometry and RNA binding protein immunoprecipitation, EIF5 was identified to interact with LINC00894. Furthermore, LINC00894 knockdown decreased EIF5 protein expression, whereas LINC00894 overexpression increased EIF5 protein expression in SH-SY5Y and BE(2)-M17 (M17) neuroblastoma cells. Additionally, LINC00894 affected the ubiquitination modification of EIF5. Adeno-associated virus (AAV) mediated LINC00894 overexpression in the brain inhibited the expression of activated Caspase-3, while increased EIF5 protein level in rats and mice subjected to transient middle cerebral artery occlusion reperfusion (MCAO/R). Meanwhile, LINC00894 knockdown increased the number of apoptotic cells and expression of activated Caspase-3, and its overexpression decreased them in the oxygen–glucose deprivation and reoxygenation (OGD/R) in vitro models. Further, LINC00894 was revealed to regulated ATF4 protein expression in condition of OGD/R and normoxia. LINC00894 knockdown also decreased the expression of glutamate-cysteine ligase catalytic subunit (GCLC) and ATF4, downregulated glutathione (GSH), and the ratio of GSH to oxidized GSH (GSH: GSSG) in vitro. By using RNA-seq combined with qRT-PCR and immunoblot, we identified that fibroblast growth factor 21 (FGF21) and aconitate decarboxylase 1 (ACOD1), as the ATF4 target genes were regulated by LINC00894 in the MCAO/R model. Finally, we revealed that ATF4 transcriptionally regulated FGF21 and ACOD1 expression; ectopic overexpression of FGF21 or ACOD1 in LINC00894 knockdown cells decreased activated Caspase-3 expression in the OGD/R model. Our results demonstrated that LINC00894 regulated cerebral ischemia injury by stabilizing EIF5 and facilitating EIF5-ATF4-dependent induction of FGF21 and ACOD1.

Targeting PAX8 sensitizes ovarian cancer cells to ferroptosis by inhibiting glutathione synthesis.

Ovarian cancer is a malignant tumor originating from the ovary, characterized by its high mortality rate and propensity for recurrence. In some patients, especially those with recurrent cancer, conventional treatments such as surgical resection or standard chemotherapy yield suboptimal results. Consequently, there is an urgent need for novel anti-cancer therapeutic strategies. Ferroptosis is a distinct form of cell death separate from apoptosis. Ferroptosis inducers have demonstrated promising potential in the treatment of ovarian cancer, with evidence indicating their ability to enhance ovarian cancer cell sensitivity to cisplatin. However, resistance of cancer cells to ferroptosis still remains an inevitable challenge. Here, we analyzed genome-scale CRISPR-Cas9 loss-of function screens and identified PAX8 as a ferroptosis resistance protein in ovarian cancer. We identified PAX8 as a susceptibility gene in GPX4-dependent ovarian cancer. Depletion of PAX8 rendered GPX4-dependent ovarian cancer cells significantly more sensitive to GPX4 inhibitors. Additionally, we found that PAX8 inhibited ferroptosis in ovarian cancer cells. Combined treatment with a PAX8 inhibitor and RSL3 suppressed ovarian cancer cell growth, induced ferroptosis, and was validated in a xenograft mouse model. Further exploration of the molecular mechanisms underlying PAX8 inhibition of ferroptosis mutations revealed upregulation of glutamate-cysteine ligase catalytic subunit (GCLC) expression. GCLC mediated the ferroptosis resistance induced by PAX8 in ovarian cancer. In conclusion, our study underscores the pivotal role of PAX8 as a therapeutic target in GPX4-dependent ovarian cancer. The combination of PAX8 inhibitors such as losartan and captopril with ferroptosis inducers represents a promising new approach for ovarian cancer therapy.

Abstract LB096: Telomere length as a predictor of therapy response and survival in patients diagnosed with ovarian carcinoma

Abstract Impaired telomere length (TL) maintenance in ovarian tissue may play a pivotal role in epithelial ovarian carcinoma (OvC) onset. TL in either target or surrogate tissue (blood) is currently being investigated as a predictor in anti-OvC therapy or as a biomarker of the disease progression, respectively. There is presently an urgent need for an appropriate approach to chemotherapy response prediction. We performed a monochrome multiplex qPCR measurement of TL in peripheral blood and tumor tissues of 209 OvC patients. Methylation status and gene expression of shelterin complex and telomerase catalytic subunit (hTERT) were determined within tumor tissues by High-Throughput DNA methylation profiling and RNA sequencing (RNA-Seq) analysis, respectively. The patients sensitive to cancer treatment (n=46) had shorter telomeres in peripheral blood cells compared to those treatment-resistant (n=93; P=0.037). Cancer tissue TL lower than the median predisposed to better overall survival (P=0.002). Gene expression of TPP1, which recruits telomerase to telomeres, was positively associated with TL in tumor tissue (P=0.026). TL measured in peripheral blood cells could serve as a marker of platinum therapy response in OvC patients. Additionally, TL determined in tumor tissue provides information on OvC patients' overall survival. The study was financed by the project NPO (LX22NPO05102), the Czech Health Research Council (NU21-03-00145), and the Czech Science Foundation (21-27902S). Citation Format: Kristyna Tomasova, Karolina Seborova, Michal Kroupa, Josef Horak, Ludmila Vodickova, Lukas Rob, Martin Hruda, Marcela Mrhalova, Alena Bartakova, Jiri Bouda, Thomas Fleischer, Vessela Kristensen, Pavel Vodicka, Radka Vaclavikova. Telomere length as a predictor of therapy response and survival in patients diagnosed with ovarian carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB096.

Protective Mechanisms of Juncus effusus and Carbonized Juncus effusus against D-Galactosamine-Induced Acute Liver Injury in Mice.

This study investigated the hepatoprotective effects of Juncus effusus (J. effusus) and Carbonized J. effusus against liver injury caused by D-galactosamine (D-GalN) in mice. J. effusus and Carbonized J. effusus were administered by gavage once daily starting seven days before the D-GalN treatment. The results of the study indicated that J. effusus and Carbonized J. effusus suppressed the D-GalN-induced generation of serum alanine transaminase (ALT), aspartate aminotransferase (AST), hepatic malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) was observed. The values of superoxide dismutase (SOD) exhibited an increase. In addition, J. effusus and Carbonized J. effusus promoted the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2), NADPH quinone oxidoreductase-1 (NQO-1), heme oxygenase-1 (HO-1) as well as the mRNA expression of Nrf2, HO-1, NQO-1 and Glutamate cysteine ligase catalytic subunit (GCLC). The compressed Carbonized J. effusus demonstrated the optimum impact. These results suggest that J. effusus and Carbonized J. effusus protect against D-GalN-induced acute liver injury through the activation of the Nrf2 pathway.

Cystine deprivation triggers CD36-mediated ferroptosis and dysfunction of tumor infiltrating CD8+ T cells

Cancer cells develop multiple strategies to evade T cell-mediated killing. On one hand, cancer cells may preferentially rely on certain amino acids for rapid growth and metastasis. On the other hand, sufficient nutrient availability and uptake are necessary for mounting an effective T cell anti-tumor response in the tumor microenvironment (TME). Here we demonstrate that tumor cells outcompete T cells for cystine uptake due to high Slc7a11 expression. This competition induces T-cell exhaustion and ferroptosis, characterized by diminished memory formation and cytokine secretion, increased PD-1 and TIM-3 expression, as well as intracellular oxidative stress and lipid-peroxide accumulation. Importantly, either Slc7a11 deletion in tumor cells or intratumoral cystine supplementation improves T cell anti-tumor immunity. Mechanistically, cystine deprivation in T cells disrupts glutathione synthesis, but promotes CD36 mediated lipid uptake due to dysregulated cystine/glutamate exchange. Moreover, enforced expression of glutamate-cysteine ligase catalytic subunit (Gclc) promotes glutathione synthesis and prevents CD36 upregulation, thus boosting T cell anti-tumor immunity. Our findings reveal cystine as an intracellular metabolic checkpoint that orchestrates T-cell survival and differentiation, and highlight Gclc as a potential therapeutic target for enhancing T cell anti-tumor function.

Activating astrocytic α2A adrenoceptors in hippocampus reduces glutamate toxicity to attenuate sepsis-associated encephalopathy in mice

BackgroundGlutamate metabolism disorder is an important mechanism of sepsis-associated encephalopathy (SAE). Astrocytes regulate glutamate metabolism. In septic mice, α2A adrenoceptor (α2A-AR) activation in the central nervous system provides neuroprotection. α2A-ARs are expressed abundantly in hippocampal astrocytes. This study was performed to determine whether hippocampal astrocytic α2A-AR activation confers neuroprotection against SAE and whether this protective effect is astrocyte specific and achieved by the modulation of glutamate metabolism. MethodsMale C57BL/6 mice with and without α2A-AR knockdown were subjected to cecal ligation and puncture (CLP). They were treated with intrahippocampal guanfacine (an α2A-AR agonist) or intraperitoneal dexmedetomidine in the presence or absence of dihydrokainic acid [DHK; a glutamate transporter 1 (GLT-1) antagonist] and/or UCPH-101 [a glutamate/aspartate transporter (GLAST) antagonist]. Hippocampal tissue was collected for the measurement of astrocyte reactivity, GLT-1 and GLAST expression, and glutamate receptor subunit 2B (GluN2B) phosphorylation. In vivo real-time extracellular glutamate concentrations in the hippocampus were measured by ultra-performance liquid chromatography tandem mass spectrometry combined with microdialysis, and in vivo real-time hippocampal glutamatergic neuron excitability was assessed by calcium imaging. The mice were subjected to the Barnes maze and fear conditioning tests to assess their learning and memory. Golgi staining was performed to assess changes in the hippocampal synaptic structure. In vitro, primary astrocytes with and without α2A-AR knockdown were stimulated with lipopolysaccharide (LPS) and treated with guanfacine or dexmedetomidine in the presence or absence of 8-bromo- cyclic adenosine monophosphate (8-Br-cAMP, a cAMP analog). LPS-treated primary and BV2 microglia were also treated with guanfacine or dexmedetomidine. Astrocyte reactivity, PKA catalytic subunit, GLT-1 an GLAST expression were determined in primary astrocytes. Interleukin-1β, interleukin-6 and tumor necrosis factor-alpha in the medium of microglia culture were measured. ResultsCLP induced synaptic injury, impaired neurocognitive function, increased astrocyte reactivity and reduced GLT-1 and GLAST expression in the hippocampus of mice. The extracellular glutamate concentration, phosphorylation of GluN2B at Tyr-1472 and glutamatergic neuron excitability in the hippocampus were increased in the hippocampus of septic mice. Intraperitoneal dexmedetomidine or intrahippocampal guanfacine administration attenuated these effects. Hippocampal astrocytes expressed abundant α2A-ARs; expression was also detected in neurons but not microglia. Specific knockdown of α2A-ARs in hippocampal astrocytes and simultaneous intrahippocampal DHK and UCPH-101 administration blocked the neuroprotective effects of dexmedetomidine and guanfacine. Intrahippocampal administration of DHK or UCPH-101 alone had no such effect. In vitro, guanfacine or dexmedetomidine inhibited astrocyte reactivity, reduced PKA catalytic subunit expression, and increased GLT-1 and GLAST expression in primary astrocytes but not in primary astrocytes that received α2A-AR knockdown or were treated with 8-Br-cAMP. Guanfacine or dexmedetomidine inhibited microglial reactivity in BV2 but not primary microglia. ConclusionsOur results suggest that neurocognitive protection against SAE after hippocampal α2A-AR activation is astrocyte specific. This protection may involve the inhibition of astrocyte reactivity and alleviation of glutamate neurotoxicity, thereby reducing synaptic injury. The cAMP/protein kinase A (PKA) signaling pathway is a potential cellular mechanism by which activating α2A-AR modulates astrocytic function.

Epithelial-Mesenchymal Transition Induced by a Metal Mixture in Liver Cells With Antioxidant Barrier Decreased.

Occupational exposure to arsenic (As), cadmium (Cd), and lead (Pb) affects many sectors, necessitating research to understand their transformation mechanisms. In this study, we characterized the process of epithelial-mesenchymal transition (EMT) in a rat hepatic epithelial cell line with decreased expression of catalase and glutamate cysteine ligase catalytic (GCLC) subunit that was exposed to a mixture of As, Cd, and Pb at equimolar occupational exposure concentrations. We evaluated the expression of genes and proteins involved in EMT. Our findings revealed that cells with a decreased antioxidant barrier showed a decreased expression and abundance of epithelial genes when exposed to a mixture of metals. Additionally, we observed alterations in the expression of transcription factors (TFs) associated with EMT and an increase in the expression and abundance of mesenchymal genes. Specifically, we found that E-cadherin expression decreased by ~50% at both the gene and protein levels. In contrast, the expression of vimentin, α-smooth muscle actin, and N-cadherin genes increased by ~70%, whereas their corresponding protein levels increased by nearly 100%. Furthermore, the TFs zinc finger e-box binding homeobox 1 and snail family transcriptional repressor 1 showed a 30% increase in gene expression and an ~80% increase in protein expression. These changes enable the cells to acquire migratory capabilities. Our results confirmed that exposure to this mixture of As, Cd, and Pb can induce EMT in cells with a decreased antioxidant barrier.

Rosmarinic Acid Inhibits Ultraviolet B-Mediated Oxidative Damage via the AKT/ERK-NRF2-GSH Pathway In Vitro and In Vivo.

Rosmarinic acid (RA) is a phenolic ester that protects human keratinocytes against oxidative damage induced by ultraviolet B (UVB) exposure, however, the mechanisms underlying its effects remain unclear. This study aimed to elucidate the cell signaling mechanisms that regulate the antioxidant activity of RA and confirm its cyto-protective role. To explore the signaling mechanisms, we used the human keratinocyte cell line HaCaT and SKH1 hairless mouse skin. RA enhanced glutamate-cysteine ligase catalytic subunit (GCLC) and glutathione synthetase (GSS) expression in HaCaT cells in a dose- and time-dependent manner. Moreover, RA induced nuclear factor erythroid-2-related factor 2 (NRF2) nuclear translocation and activated the signaling kinases protein kinase B (AKT) and extracellular signal-regulated kinase (ERK). Treatment with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, the ERK inhibitor U0126, and small interfering RNA (siRNA) gene silencing suppressed RA-enhanced GCLC, GSS, and NRF2 expression, respectively. Cell viability tests showed that RA significantly prevented UVB-induced cell viability decrease, whereas the glutathione (GSH) inhibitors buthionine sulfoximine, LY294002, and U0126 significantly reduced this effect. Moreover, RA protected against DNA damage and protein carbonylation, lipid peroxidation, and apoptosis caused by UVB-induced oxidative stress in a concentration-dependent manner in SKH1 hairless mouse skin tissues. These results suggest that RA protects against UVB-induced oxidative damage by activating AKT and ERK signaling to regulate NRF2 signaling and enhance GSH biosynthesis. Thus, RA treatment may be a promising approach to protect the skin from UVB-induced oxidative damage.

Eicosapentaenoic acid enhances the sensitivity of osteosarcoma to cisplatin by inducing ferroptosis through the DNA-PKcs/AKT/NRF2 pathway and reducing PD-L1 expression to attenuate immune evasion

Acquired drug resistance poses a significant challenge in osteosarcoma therapy. Therefore, it is necessary for us to discover and develop an alternative anti-cancer strategy. Previous studies have shown that eicosapentaenoic acid (EPA) significantly increases chemosensitivity in cancer cells. In this study, we discovered that EPA enhances the sensitivity of osteosarcoma to cisplatin (DDP). Interestingly, in addition to inhibiting growth and inducing apoptosis, EPA also enhances DDP-induced ferroptosis. Western blot analysis confirmed that EPA treatment significantly decreases the expression of DNA-dependent protein kinase catalytic subunit (DNA-PKcs), p-AKT, nuclear factor erythroid 2-related factor 2 (NRF2), and glutathione peroxidase 4 (GPX4) in cells. Knockdown of DNA-PKcs by siRNA further enhances the level of ferroptosis induced by EPA. Importantly, EPA can reverse the high expression level of programmed death ligand 1 (PD-L1) induced by DDP. ELISA and western blotting analysis revealed that EPA treatment decreases the levels of IL-6 and p-STAT3, which are increased by DDP treatment. Furthermore, a co-immunoprecipitation (co-IP) assay confirmed the interaction between DNA-PKcs and PD-L1, and knockdown of DNA-PKcs further reduces the expression of PD-L1. This data provides the first evidence that EPA suppresses the DNA-PKcs/AKT/NRF2/GPX4 pathway to enhance ferroptosis, and inhibits IL-6/STAT3 and DNA-PKcs to decrease PD-L1 expression, thereby sensitizing osteosarcoma to DDP. The combination of EPA and DDP presents an encouraging and promising anti-tumor strategy.

ACTL6A protects gastric cancer cells against ferroptosis through induction of glutathione synthesis

Gastric cancer (GC), one of the most common malignant tumors in the world, exhibits a rapid metastasis rate and causes high mortality. Diagnostic markers and potential therapeutic targets for GCs are urgently needed. Here we show that Actin-like protein 6 A (ACTL6A), encoding an SWI/SNF subunit, is highly expressed in GCs. ACTL6A is found to be critical for regulating the glutathione (GSH) metabolism pathway because it upregulates γ-glutamyl-cysteine ligase catalytic subunit (GCLC) expression, thereby reducing reactive oxygen species (ROS) levels and inhibiting ferroptosis, a regulated form of cell death driven by the accumulation of lipid-based ROS. Mechanistic studies show that ACTL6A upregulates GCLC as a cotranscription factor with Nuclear factor (erythroid-derived 2)-like 2 (NRF2) and that the hydrophobic region of ACTL6A plays an important role. Our data highlight the oncogenic role of ACTL6A in GCs and indicate that inhibition of ACTL6A or GCLC could be a potential treatment strategy for GCs.

Mechanisms of Yajieshaba in the treatment of liver fibrosis through the Keap1-Nrf2 signaling pathway.

Yajieshaba (YJSB), a traditional Dai medicine formula containing botanical drugs, is commonly employed in Yunnan due to its significant therapeutic effects on liver protection. Consequently, to determine the efficacy of YJSB and the mechanism of action of Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway against liver fibrosis. We wanted to see if YJSB could treat CCl4-induced liver fibrosis by regulating the Keap1-Nrf2 signaling pathway. YJSB significantly improved liver function biochemical indices, liver fibrosis quadruple, hydroxyproline (Hyp), and transforming growth factor-β1 (TGF-β1) levels. The staining results demonstrated that the degree of liver fibrosis was significantly reduced. YJSB reduced the content of malondialdehyde (MDA) and elevated the content of superoxide dismutase (SOD) in the liver, exhibiting antioxidant effects; meanwhile, it regulated the expression of Keap1-Nrf2 pathway protein, increased the expression of NAD(P)H: Quinone oxidoreductase (NQO1), Heme Oxygenase 1 (HO-1), Glutamate cysteine ligase modifier subunit (GCLM), and Glutamate cysteine ligase catalytic subunit (GCLC) expression in the liver decreased while Nrf2 expression increased. Fluorescence immunoassay studies demonstrated that YJSB promoted the trans-nuclearization of Nrf2. YJSB possesses anti-liver fibrosis pharmacological effects that improve liver function and effectively counteract CCl4-induced liver fibrosis damage. The mechanism of action might be related to the regulation of protein expression of the Keap1-Nrf2 pathway, increasing the ability of the body to resist oxidative stress and reduce oxidative stress injury.

Effects of Exhaustive Exercise on Inflammatory, Apoptotic, and Antioxidative Signaling Pathways in Human Peripheral Blood Mononuclear Cells.

In the present study, we investigated the effects of exhaustive exercise and recovery on inflammatory, pro-apoptotic, and anti-oxidative responses in human peripheral blood mononuclear cells (PBMCs). Sixteen volunteers participated in a guided physical activity program in which they were subjected to progressive exercise on the treadmill until they were exhausted followed by an 1-hour recovery period. Isolated human PBMCs were collected before exercise, immediately after exercise, and after 1-hour recovery. Exhaustive exercise induced expression of heme oxygenase-1 and glutamate cysteine ligase catalytic subunit and activation of NF-κB and NF-E2 related factor 2 (Nrf2). Apoptosis, as measured by activity and cleavage of caspase-3 and its substrate PARP also significantly increased. However, induction of redox signaling and the pro-apoptotic response fully returned to the baseline level during the 1-hour recovery period. On the other hand, COX-2 expression was continuously elevated after exercise cessation throughout the 1-hour recovery period. Taking all these findings into account, we conclude that exhaustive exercise transiently induces Nrf2-mediated antioxidant gene expression and eliminates damaged cells through apoptosis as part of an adaptive cytoprotective response against oxidative and inflammatory stress.

Echinacoside from Cistanche tubulosa ameliorates alcohol-induced liver injury and oxidative stress by targeting Nrf2.

Cistanche tubulosa (Schrenk) Wight, named Guan hua Rou Cong-Rong in Chinese, is a traditional plant with liver, kidney, and intestine protective effects. Echinacoside (ECH) is its active constituent and has been found to have various biological effects, including antioxidative stress and anti-inflammatory effects. Liver injury caused by acetaminophen or CCL4 has been proven to benefit from ECH; however, the effects of ECH against alcoholic liver disease (ALD) remain unclear. This study was used to estimate the effect of echinacoside on nuclear factor erythroid 2-related factor 2 (Nrf2), which ameliorates ALD by inhibiting oxidative stress and cell apoptosis through affecting Nrf2.A mouse model of ALD was established with ethanol using hematoxylin and eosin (HE) staining, oiled staining, and biochemical indices. Alpha Mouse Liver 12 (AML-12) cells were induced with ethanol in vitro and analyzed using western blotting, flow cytometry, and biochemical assays. In the animal model of ALD, ECH dramatically reduced liver damage, as proven by the downregulation of aspartate aminotransferase (AST) and HE staining. In vitro, ECH distinctly reduced the damage caused by ethanol through the decreased expression of cleaved caspase-3 measured by western blotting. ECH significantly increased the activity of Nrf2 in vivo and in vitro. Nrf2 knockout may diminish the influence of ECH on ALD. Meanwhile, ECH also increased the expression of haem oxygenase-1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC), while it inhibited levels of oxidative stress and cell apoptosis. Our findings suggest that ECH protects against ethanol-induced liver injuries by alleviating oxidative stress and cell apoptosis by increasing the activity of Nrf2. Therefore, ECH is promising for the treatment of ALD.

Impact of AMPK on cervical carcinoma progression and metastasis

Cervical cancer (CC) is the fourth most common malignant neoplasm among women. Late diagnosis is directly associated with the incidence of metastatic disease and remarkably limits the effectiveness of conventional anticancer therapies at the advanced tumor stage. In this study, we investigated the role of 5’AMP-activated kinase (AMPK) in the metastatic progression of cervical cancer. Since the epithelial mesenchymal transition (EMT) is known as major mechanism enabling cancer cell metastasis, cell lines, which accurately represent this process, have been used as a research model. We used C-4I and HTB-35 cervical cancer cell lines representing distant stages of the disease, in which we genetically modified the expression of the AMPK catalytic subunit α. We have shown that tumor progression leads to metabolic deregulation which results in reduced expression and activity of AMPK. We also demonstrated that AMPK is related to the ability of cells to acquire invasive phenotype and potential for in vivo metastases, and its activity may inhibit these processes. Our findings support the hypothesis that AMPK is a promising therapeutic target and modulation of its expression and activity may improve the efficacy of cervical cancer treatment.

ALKBH1-mediated m1 A demethylation of METTL3 mRNA promotes the metastasis of colorectal cancer by downregulating SMAD7 expression.

Colorectal cancer (CRC) is one of the most common malignancies, and the main cause of death from CRC is tumor metastasis. m1 A RNA modification plays critical role in many biological processes. However, the role of m1 A modification in CRC remains unclear. Here, we find that the m1 A demethylase alkB homolog 1, histone H2A dioxygenase (ALKBH1) is overexpressed in CRC and is associated with metastasis and poor prognosis. Upregulation of ALKBH1 expression promotes CRC metastasis in vitro and in vivo. Mechanistically, knockdown of ALKBH1 results in a decrease in methyltransferase 3, N6-adenosine-methyltransferase complex catalytic subunit (METTL3) expression, probably due to m1 A modification of METTL3 mRNA, followed by m6 A demethylation of SMAD family member 7 (SMAD7) mRNA. In addition, downregulation of SMAD7 establishes an aggressive phenotype. More importantly, the cell migration and invasion defects caused by ALKBH1 depletion or METTL3 depletion are significantly reversed by SMAD7 silencing. Considering these results collectively, we propose that ALKBH1 promotes CRC metastasis by destabilizing SMAD7 through METTL3.