PRMT6 promotes tumorigenicity and cisplatin response of lung cancer through triggering 6PGD/ENO1 mediated cell metabolism

Warburg effect and lactylation in cancer: mechanisms for chemoresistance

In the clinical management of cancers, the emergence of chemoresistance represents a profound and imperative "pain point" that requires immediate attention. Understanding the mechanisms of chemoresistance is essential for developing effective therapeutic strategies. Importantly, existing studies have demonstrated that glucose metabolic reprogramming, commonly referred to as the Warburg effect or aerobic glycolysis, is a major contributor to chemoresistance. Additionally, lactate, a byproduct of aerobic glycolysis, functions as a signaling molecule that supports lysine lactylation modification of proteins, which also plays a critical role in chemoresistance. However, it is insufficient to discuss the role of glycolysis or lactylation in chemoresistance from a single perspective. The intricate relationship between aerobic glycolysis and lactylation plays a crucial role in promoting chemoresistance. Thus, a thorough elucidation of the mechanisms underlying chemoresistance mediated by aerobic glycolysis and lactylation is essential. This review provides a comprehensive overview of these mechanisms and further outlines that glycolysis and lactylation exert synergistic effects, promoting the development of chemoresistance and creating a positive feedback loop that continues to mediate this resistance. The close link between aerobic glycolysis and lactylation suggests that the application of glycolysis-related drugs or inhibitors in cancer therapy may represent a promising anticancer strategy. Furthermore, the targeted application of lactylation, either alone or in combination with other treatments, may offer new therapeutic avenues for overcoming chemoresistance.

SIX1 enhances aerobic glycolysis and progression in cervical cancer through ENO1

Cervical cancer is a significant threat to women's health, and its incidence in China has been increasing in recent years. Treating advanced and recurrent cervical cancer has become increasingly challenging, highlighting the urgent need to identify new therapeutic targets for this disease. SIX1 is associated with cell proliferation, metastasis, and chemoresistance in various human malignancies. SIX1 overexpression in cervical cancer tissues has been linked to increased clinical stage and lymph node metastasis; however, the regulatory function of SIX1 in cervical cancer remains largely unexplored. In this study, we found that SIX1 promotes cervical cancer cell proliferation, invasion, and migration by enhancing glucose metabolism. Additionally, SIX1 was shown to influence the glycolytic process in cervical cancer by upregulating GLUT1, PFK1, PGK1, ENO1, and PKM2 expression. Furthermore, we identified a binding site for SIX1 in the ENO1 promoter region, demonstrating that SIX1 has a regulatory effect. These results suggest that SIX1 regulates proliferation and glucose metabolism in cervical cancer cells by promoting the transcription of key glycolytic enzymes, such as ENO1. Understanding this regulatory mechanism is crucial for identifying potential therapeutic targets for cervical cancer.

IGF-Binding Protein 7 and Cadmium-Induced Hepatorenal Fibrosis

Key Points

Background

Chronic cadmium exposure can induce the onset and progression of hepatorenal fibrosis; however, its molecular basis is unclear. IGF-binding protein 7 (IGFBP7) is not only a biomarker of AKI but also plays a functional role in promoting kidney injury and inflammation. Abnormal repair of AKI causes kidney fibrosis and CKD. IGFBP7 has also been reported as a more sensitive biomarker for liver fibrosis. However, its role in hepatorenal fibrosis requires further investigation.

Methods

IGFBP7 global and conditional knockout mice were used to determine the role of IGFBP7 in cadmium-induced hepatorenal fibrosis. Then, liquid chromatography–mass spectrometry, truncated mutants, coimmunoprecipitation, and microscale thermophoresis were used to unravel the downstream mechanisms.

Results

IGFBP7 expression was significantly elevated in kidney and liver tissues of mice subjected to chronic cadmium exposure. IGFBP7 deficiency attenuated cadmium-induced hepatorenal dysfunction and fibrosis, whereas restoration of IGFBP7 expression in IGFBP7-deficient mice reproduced hepatorenal fibrosis. Mechanistically, IGFBP7 interacted with α-enolase (ENO1) and inhibited its ubiquitination and degradation. Upregulated ENO1 further promoted glucose metabolic reprogramming and lactate accumulation. Conversely, lactate accumulation enhanced IGFBP7 transcription and expression through histone H3K18 lactylation. Importantly, therapy targeting IGFBP7 significantly ameliorated cadmium-induced hepatorenal fibrosis.

Conclusions

IGFBP7 promoted cadmium-induced hepatorenal fibrosis by enhancing ENO1-driven abnormal glycolysis and lactate accumulation.

RFWD3 Reprograms Nucleotide Metabolism Through PHGDH to Induce Chemoresistance In Osteosarcoma

Chemoresistance represents a major challenge for osteosarcoma treatment. Despite the improved knowledge of cancer biology, the core determinants of cisplatin (DDP) resistance in osteosarcoma remain unclear and deserve further exploration. Here, RFWD3 is identified as a key regulator of DDP sensitivity in osteosarcoma using a genome-wide CRISPR screen. It is demonstrated that RFWD3 is overexpressed in post-chemotherapy osteosarcoma tissues compared to pre-chemotherapy tissues. Knocking out RFWD3 increased the sensitivity of osteosarcoma cells to DDP treatment. Mechanistically, RFWD3 bound to and ubiquitinated PHGDH at the Lys137 residue, promoting its degradation and conserving cellular oxidized nicotinamide adenine dinucleotide (NAD+). The resulting surplus of NAD+ enhanced the TCA cycle, leading to increased production of aspartic acid and glutamic acid for de novo nucleotide biosynthesis. In addition, virtual screening techniques are employed to identify Lomitapide as a specific inhibitor of the RFWD3-PHGDH interaction, capable of disrupting the binding between RFWD3 and PHGDH. It is found that Lomitapide exhibits a significant synergistic anti-osteosarcoma effect when combined with DDP. In conclusion, a specific role of RFWD3 in regulating nucleotide metabolism is revealed and comprised of targetable candidates for overcoming chemoresistance in osteosarcoma.

Inhibition of 6-phosphogluconate dehydrogenase suppresses esophageal squamous cell carcinoma growth and enhances the anti-tumor effects of metformin via the AMPK/mTOR pathway

Metabolic reprogramming plays a pivotal role in the development and progression of tumors. Tumor cells rely on glycolysis as their primary energy production pathway and effectively utilize biomolecules generated by the pentose phosphate pathway (PPP) for efficient biosynthesis. However, the role of 6-phosphogluconate dehydrogenase (6PGD), a crucial enzyme in the PPP, remains unexplored in esophageal squamous cell carcinoma (ESCC). In this study, we observed a significant upregulation of 6PGD expression in ESCC tissues, which correlated with an unfavorable prognosis among patients. The experiments demonstrated that knockdown of 6PGD induces oxidative stress and suppresses ESCC cell proliferation. Mechanistically, this is achieved through AMPK activation and subsequent inhibition of downstream mTOR phosphorylation. Moreover, physcion has been found to inhibit 6PGD activity and exert its anti-ESCC effect via the AMPK/mTOR pathway. Subsequently, we conducted both in vitro and in vivo experiments to validate the anticancer efficacy of combining metformin, an AMPK activator, with physcion. The results demonstrated a significantly enhanced inhibition of ESCC growth. This study elucidates the impact of 6PGD on ESCC cell proliferation along with its underlying molecular mechanisms, highlighting its potential as a therapeutic target for ESCC. Furthermore, we investigated a novel approach for improved anti-tumor therapy involving physcion and metformin. These findings will contribute new insights to clinical treatment strategies for ESCC while providing a theoretical foundation for developing molecular targeted therapies.

EMC2 promotes breast cancer progression and enhances sensitivity to PDK1/AKT inhibition by deubiquitinating ENO1

Breast cancer is the most common malignant tumor worldwide, causing 685,000 deaths in 2020, and this number continues to rise. Identifying the molecular mechanisms driving breast cancer progression and potential therapeutic targets are currently urgent issues. Our previous work and bioinformatics analysis shows that the expression of Endoplasmic Reticulum Membrane Protein Complex Subunit 2 (EMC2) is up-regulated in breast cancer and is correlated with shortened overall survival of patients. However, the mechanism of EMC2 in breast cancer is yet to be elucidated. In this study, we identified that EMC2 promotes breast cancer proliferation and metastasis by activating the PDK1/AKT (T308)/mTOR (S2448) signaling pathway and can serve as a candidate target for PDK1/AKT inhibition. Mechanistically, EMC2 serves as a "scaffold" protein to recruit the deubiquitinating enzyme (DUB) USP7 for ENO1 deubiquitylation to stabilize its expression, thereby initiating downstream B-MYB/PDK1/AKT (T308)/mTOR (S2448) signal cascade. Silencing EMC2 significantly weaken the proliferation/metastasis potential of breast cancer in vitro and in vivo, but made tumor cell sensitive to PDK1/AKT inhibition. Overexpression of EMC2 leads to exactly the opposite result. This study reveals the EMC2/USP7/ENO1/B-MYB protumorigenic axis in breast cancer and identifies EMC2 as a candidate target for PDK1/AKT inhibitory therapy.

Chaetocin, a Natural Inhibitor of Transketolase, Suppresses the Non-Oxidative Pentose Phosphate Pathway and Inhibits the Growth of Drug-Resistant Non-Small Cell Lung Cancer

Worldwide, lung cancer is the most common cause of cancer-related death, which is made worse by the development of drug resistance during treatment. It is urgent to develop new therapeutic methods and small molecule drugs for tumor resistance. Chaetocin, extracted from Chaetomium minutum, is a natural compound with good antitumor activity. However, there are few studies on its tumor resistance. In this paper, firstly, chaetotocin significantly inhibited the viability and migration of cisplatin-resistant non-small cell lung cancer (NSCLC) cells and inhibited the xenograft growth of nude mice. Chaetocin at 4 mg/kg significantly inhibited A549/DDP xenograft growth with an inhibition rate of 70.43%. Subsequently, the underlying mechanism behind the actions of chaetocin was explored. It was discovered that chaetocin can inhibit transketolase (TKT), thereby inhibiting the growth of NSCLC cells and inducing cell death. Compared with cisplatin-sensitive cells, a lower concentration of chaetocin can inhibit cisplatin-resistance cell viability and migration. Mechanistically, TKT was identified as a potential target for chaetocin. The KD value of the interaction between chaetocin and TKT was 63.2 μM. An amount of 0.2 μM chaetocin may suppress the enzyme activity and expression level of TKT. We found the TKT expression is higher in cisplatin-resistant cells, which further explains why these cells were more vulnerable to chaetocin in terms of cell phenotype. Additionally, the muti-omics analysis and RNA interference suggested that chaetocin can inhibit the PI3K/Akt signaling pathway through TKT. In conclusion, chaetocin could directly bind to TKT, inhibiting its enzyme activity and expression, which interfered with intracellular metabolism and oxidation-reduction balance, and then regulated the PI3K/Akt signaling pathway to inhibit the growth of NSCLC and induce apoptosis.

Opto-Epigenetic Regulation of Histone Arginine Asymmetric Dimethylation via Type I Protein Arginine Methyltransferase Inhibition

Histone arginine asymmetric dimethylation, which is mainly catalyzed by type I protein arginine methyltransferases (PRMTs), is involved in broad biological and pathological processes. Recently, several type I PRMT inhibitors, such as MS023, have been developed to reverse the histone arginine dimethylation status in tumor cells, but extensive inhibition of type I PRMTs may cause side effects in normal tissues. Herein, we designed a photoactivatable MS023 prodrug (C-MS023) to achieve spatiotemporal inhibition of histone arginine asymmetric dimethylation. In vitro studies showed that C-MS023 exhibited reduced potency in inhibiting type I PRMTs. Importantly, visible light irradiation at 420 nm could trigger the photolysis of the prodrug, thereby liberating MS023 for effective downregulation of histone arginine asymmetric dimethylation and DNA replication-related transcriptomic activities. This opto-epigenetic small-molecule prodrug potentially aids in further research into the pathophysiological functions of type I PRMTs and the development of targeted epigenetic therapeutics.

PRMT6 promotes colorectal cancer progress via activating MYC signaling

Colorectal cancer (CRC) remains a major global health challenge, with high rates of incidence and mortality. This study investigates the role of protein arginine methyltransferase 6 (PRMT6) as an oncogene in CRC and its mechanistic involvement in tumor progression. We found that PRMT6 is significantly overexpressed in CRC tissues compared to adjacent normal tissues and is associated with poorer patient survival. Functional assays demonstrated that PRMT6 promotes CRC cell proliferation, migration, and invasion. Mechanistically, PRMT6 enhances MYC signaling by stabilizing c-MYC through mono-methylation at arginine 371, which inhibits c-MYC poly-ubiquitination and subsequent degradation. This post-translational modification is crucial for PRMT6-induced cancer cell proliferation. Xenograft models further validated that PRMT6 knockdown results in reduced tumor growth and decreased c-MYC levels. Our findings highlight PRMT6 as a key regulator of c-MYC stability and CRC progression, suggesting that targeting PRMT6 or its effects on c-MYC could offer a promising strategy for CRC treatment.

Overview of the PRMT6 modulators in cancer treatment: Current progress and emerged opportunity

Protein Arginine Methyltransferase 6 (PRMT6) is a Type I PRMT enzyme that plays a role in the epigenetic regulation of gene expression by methylating histone and non-histone proteins. It is also involved in various cellular processes, including alternative splicing, DNA repair, and cell signaling. Furthermore, PRMT6 exerts multiple effects on cellular processes such as growth, migration, invasion, apoptosis, and drug resistance in various cancers, positioning it as a promising target for anti-tumor therapeutics. In this review, we initially provide an overview of the structure and biological functions of PRMT6, along with its association with cancer. Subsequently, we focus on recent progress in the design and development of modulators targeting PRMT6. This includes a comprehensive review of PRMT6 inhibitors (isoform-selective and non-selective), dual-target inhibitors based on PRMT6, PRMT6 covalent inhibitors, and PRMT6-targeting hydrophobic tagging (HyT) degraders, from the perspectives of rational design, pharmacodynamics, pharmacokinetics, and the clinical status of these modulators. Finally, we also provided the challenges and prospective directions for PRMT6 targeting drug discovery in cancer therapy.

Role of ENO1 and its targeted therapy in tumors

ENO1, also called 2-phospho-D-glycerate hydrolase in cellular glycolysis, is an enzyme that converts 2-phosphoglycerate to phosphoenolpyruvate and plays an important role in the Warburg effect. In various tumors, ENO1 overexpression correlates with poor prognosis. ENO1 is a multifunctional oncoprotein that, when located on the cell surface, acts as a "moonlighting protein" to promote tumor invasion and metastasis. When located intracellularly, ENO1 facilitates glycolysis to dysregulate cellular energy and sustain tumor proliferation. Additionally, it promotes tumor progression by activating oncogenic signaling pathways. ENO1 is a tumor biomarker and represents a promising target for tumor therapy. This review summarizes recent advances from 2020 to 2024 in understanding the relationship between ENO1 and tumors and explores the latest targeted therapeutic strategies involving ENO1.

O-GlcNAcylation of enolase 1 serves as a dual regulator of aerobic glycolysis and immune evasion in colorectal cancer

Aerobic glycolysis and immune evasion are two key hallmarks of cancer. However, how these two features are mechanistically linked to promote tumor growth is not well understood. Here, we show that the glycolytic enzyme enolase-1 (ENO1) is dynamically modified with an O-linked β-N-acetylglucosamine (O-GlcNAcylation), and simultaneously regulates aerobic glycolysis and immune evasion via differential glycosylation. Glycosylation of threonine 19 (T19) on ENO1 promotes its glycolytic activity via the formation of active dimers. On the other hand, glycosylation of serine 249 (S249) on ENO1 inhibits its interaction with PD-L1, decreases association of PD-L1 with the E3 ligase STUB1, resulting in stabilization of PD-L1. Consequently, blockade of T19 glycosylation on ENO1 inhibits glycolysis, and decreases cell proliferation and tumor growth. Blockade of S249 glycosylation on ENO1 reduces PD-L1 expression and enhances T cell-mediated immunity against tumor cells. Notably, elimination of glycosylation at both sites synergizes with PD-L1 monoclonal antibody therapy to promote antitumor immune response. Clinically, ENO1 glycosylation levels are up-regulated and show a positive correlation with PD-L1 levels in human colorectal cancers. Thus, our findings provide a mechanistic understanding of how O-GlcNAcylation bridges aerobic glycolysis and immune evasion to promote tumor growth, suggesting effective therapeutic opportunities.

Regulation of bacterial stringent response by an evolutionarily conserved ribosomal protein L11 methylation

Lysine and arginine methylation is an important regulator of enzyme activity and transcription in eukaryotes. However, little is known about this covalent modification in bacteria. In this work, we investigated the role of methylation in bacteria. By reanalyzing a large phyloproteomics data set from 48 bacterial strains representing six phyla, we found that almost a quarter of the bacterial proteome is methylated. Many of these methylated proteins are conserved across diverse bacterial lineages, including those involved in central carbon metabolism and translation. Among the proteins with the most conserved methylation sites is ribosomal protein L11 (bL11). bL11 methylation has been a mystery for five decades, as the deletion of its methyltransferase PrmA causes no cell growth defects. Comparative proteomics analysis combined with inorganic polyphosphate and guanosine tetra/pentaphosphate assays of the ΔprmA mutant in Escherichia coli revealed that bL11 methylation is important for stringent response signaling. In the stationary phase, we found that the ΔprmA mutant has impaired guanosine tetra/pentaphosphate production. This leads to a reduction in inorganic polyphosphate levels, accumulation of RNA and ribosomal proteins, and an abnormal polysome profile. Overall, our investigation demonstrates that the evolutionarily conserved bL11 methylation is important for stringent response signaling and ribosomal activity regulation and turnover.

IMPORTANCE

Protein methylation in bacteria was first identified over 60 years ago. Since then, its functional role has been identified for only a few proteins. To better understand the functional role of methylation in bacteria, we analyzed a large phyloproteomics data set encompassing 48 diverse bacteria. Our analysis revealed that ribosomal proteins are often methylated at conserved residues, suggesting that methylation of these sites may have a functional role in translation. Further analysis revealed that methylation of ribosomal protein L11 is important for stringent response signaling and ribosomal homeostasis.

Arginine methylation and respiratory disease

Arginine methylation, a vital post-translational modification, plays a pivotal role in numerous cellular functions such as signal transduction, DNA damage response and repair, regulation of gene transcription, mRNA splicing, and protein interactions. Central to this modification is the role of protein arginine methyltransferases (PRMTs), which have been increasingly recognized for their involvement in the pathogenesis of various respiratory diseases. This review begins with an exploration of the biochemical underpinnings of arginine methylation, shedding light on the intricate molecular regulatory mechanisms governed by PRMTs. It then delves into the impact of arginine methylation and the dysregulation of arginine methyltransferases in diverse pulmonary disorders. Concluding with a focus on the therapeutic potential and recent advancements in PRMT inhibitors, this article aims to offer novel perspectives and therapeutic avenues for the management and treatment of respiratory diseases.

METTL3-mediated m6A modification of LINC00520 confers glycolysis and chemoresistance in osteosarcoma via suppressing ubiquitination of ENO1

Chemoresistance remains the main obstacle limiting the treatment of osteosarcoma, seriously affecting the prognosis of adolescent patients with osteosarcoma. Recently, long non-coding RNAs (lncRNAs) were reported to be involved in chemoresistance, while the mechanisms of lncRNAs underlying osteosarcoma resistance to chemotherapy remain elusive. Here, LINC00520 was identified as a novel cisplatin resistance-related lncRNA in osteosarcoma, and its high expression was associated with poor prognosis of osteosarcoma patients. Functionally, LINC00520 could potentiate osteosarcoma resistance to cisplatin in vitro and in vivo. Mechanistically, LINC00520 bound to ENO1 and upregulated ENO1 protein expression by blocking FBXW7-mediated ENO1 ubiquitination and proteasomal degradation, thereby promoting glycolysis and ultimately inducing cisplatin resistance in osteosarcoma. Furthermore, METTL3 could stabilize and upregulate LINC00520 in an m6A-YTHDF2-dependent manner in osteosarcoma. This study proposes a novel lncRNA-driven mechanism for cisplatin resistance in osteosarcoma, and offers a promising therapeutic strategy for reversing chemoresistance in osteosarcoma by targeting the METTL3/LINC00520/ENO1/glycolysis axis.

Algicidal bacteria-derived membrane vesicles as shuttles mediating cross-kingdom interactions between bacteria and algae

Bacterial membrane vesicles (BMVs) are crucial biological vehicles for facilitating interspecies and interkingdom interactions. However, the extent and mechanisms of BMV involvement in bacterial-algal communication remain elusive. This study provides evidence of BMVs delivering cargos to targeted microalgae. Membrane vesicles (MVs) from Chitinimonas prasina LY03 demonstrated an algicidal profile similar to strain LY03. Further investigation revealed Tambjamine LY2, an effective algicidal compound, selectively packaged into LY03-MVs. Microscopic imaging demonstrated efficient delivery of Tambjamine LY2 to microalgae Heterosigma akashiwo and Thalassiosira pseudonana through membrane fusion. In addition, the study demonstrated the versatile cargo delivery capabilities of BMVs to algae, including the transfer of MV-carried nucleic acids into algal cells and the revival of growth in iron-depleted microalgae by MVs. Collectively, our findings reveal a previously unknown mechanism by which algicidal bacteria store hydrophobic algicidal compounds in MVs to trigger target microalgae death and highlight BMV potency in understanding and engineering bacterial-algae cross-talk.

Transcriptional regulation and post-translational modifications in the glycolytic pathway for targeted cancer therapy

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

HSV-1 reactivation results in post-herpetic neuralgia by upregulating Prmt6 and inhibiting cGAS-STING

Chronic varicella zoster virus (VZV) infection induced neuroinflammatory condition is the critical pathology of post-herpetic neuralgia (PHN). The immune escape mechanism of VZV remains elusive. As to mice have no VZV infection receptor, herpes simplex virus type 1 (HSV-1) infection is a well established PHN mice model. Transcriptional expression analysis identified that the protein arginine methyltransferases 6 (Prmt6) was upregulated upon HSV-1 infection, which was further confirmed by immunofluorescence staining in spinal dorsal horn. Prmt6 deficiency decreased HSV-1-induced neuroinflammation and PHN by enhancing antiviral innate immunity and decreasing HSV-1 load in vivo and in vitro. Overexpression of Prmt6 in microglia dampened antiviral innate immunity and increased HSV-1 load. Mechanistically, Prmt6 methylated and inactivated STING, resulting in reduced phosphorylation of TANK binding kinase-1 (TBK1) and interferon regulatory factor 3 (IRF3), diminished production of type I interferon (IFN-I) and antiviral innate immunity. Furthermore, intrathecal or intraperitoneal administration of the Prmt6 inhibitor EPZ020411 decreased HSV-1-induced neuroinflammation and PHN by enhancing antiviral innate immunity and decreasing HSV-1 load. Our findings revealed that HSV-1 escapes antiviral innate immunity and results in PHN by upregulating Prmt6 expression and inhibiting the cGAS-STING pathway, providing novel insights and a potential therapeutic target for PHN.

Dysregulation of arginine methylation in tumorigenesis

Protein methylation, similar to DNA methylation, primarily involves post-translational modification (PTM) targeting residues of nitrogen-containing side-chains and other residues. Protein arginine methylation, occurred on arginine residue, is mainly mediated by protein arginine methyltransferases (PRMTs), which are ubiquitously present in a multitude of organisms and are intricately involved in the regulation of numerous biological processes. Specifically, PRMTs are pivotal in the process of gene transcription regulation, and protein function modulation. Abnormal arginine methylation, particularly in histones, can induce dysregulation of gene expression, thereby leading to the development of cancer. The recent advancements in modification mediated by PRMTs and cancer research have had a profound impact on our understanding of the abnormal modification involved in carcinogenesis and progression. This review will provide a defined overview of these recent progression, with the aim of augmenting our knowledge on the role of PRMTs in progression and their potential application in cancer therapy.

Combining a glycolysis‑related prognostic model based on scRNA‑Seq with experimental verification identifies ZFP41 as a potential prognostic biomarker for HCC

Hepatocellular carcinoma (HCC) is a common malignancy with a poor prognosis, and its heterogeneity affects the response to clinical treatments. Glycolysis is highly associated with HCC therapy and prognosis. The present study aimed to identify a novel biomarker for HCC by exploring the heterogeneity of glycolysis in HCC. The intersection of both marker genes of glycolysis‑related cell clusters from single‑cell RNA sequencing analysis and mRNA data of liver HCC from The Cancer Genome Atlas were used to construct a prognostic model through Cox proportional hazard regression and the least absolute shrinkage and selection operator Cox regression. Data from the International Cancer Genome Consortium were used to validate the results of the analysis. Immune status analysis was then conducted. A significant gene in the prognostic model was identified as a potential biomarker and was verified through in vitro experiments. The results revealed that the glycolysis‑related prognostic model divided patients with HCC into high‑ and low‑risk groups. A nomogram combining the model and clinical features exhibited accurate predictive ability, with an area under the curve of 0.763 at 3 years. The high‑risk group exhibited a higher expression of checkpoint genes and lower tumor immune dysfunction and exclusion scores, suggesting that this group may be more likely to benefit from immunotherapy. The tumor tissues had a higher zinc finger protein (ZFP)41 mRNA and protein expression compared with the adjacent tissues. In vitro analyses revealed that ZFP41 played a crucial role in cell viability, proliferation, migration, invasion and glycolysis. On the whole, the present study demonstrates that the glycolysis‑related prognostic gene, ZFP41, is a potential prognostic biomarker and therapeutic target, and may play a crucial role in glycolysis and malignancy in HCC.

Autophagy-driven regulation of cisplatin response in human cancers: Exploring molecular and cell death dynamics

Despite the challenges posed by drug resistance and side effects, chemotherapy remains a pivotal strategy in cancer treatment. A key issue in this context is macroautophagy (commonly known as autophagy), a dysregulated cell death mechanism often observed during chemotherapy. Autophagy plays a cytoprotective role by maintaining cellular homeostasis and recycling organelles, and emerging evidence points to its significant role in promoting cancer progression. Cisplatin, a DNA-intercalating agent known for inducing cell death and cell cycle arrest, often encounters resistance in chemotherapy treatments. Recent studies have shown that autophagy can contribute to cisplatin resistance or insensitivity in tumor cells through various mechanisms. This resistance can be mediated by protective autophagy, which suppresses apoptosis. Additionally, autophagy-related changes in tumor cell metastasis, particularly the induction of Epithelial-Mesenchymal Transition (EMT), can also lead to cisplatin resistance. Nevertheless, pharmacological strategies targeting the regulation of autophagy and apoptosis offer promising avenues to enhance cisplatin sensitivity in cancer therapy. Notably, numerous non-coding RNAs have been identified as regulators of autophagy in the context of cisplatin chemotherapy. Thus, therapeutic targeting of autophagy or its associated pathways holds potential for restoring cisplatin sensitivity, highlighting an important direction for future clinical research.

Malate, a natural inhibitor of 6PGD, improves the efficacy of chemotherapy in lung cancer

OBJECTIVE

Metabolic reprogramming is an important coordinator of tumor development and resistance to therapy, such as the tendency of tumor cells to utilize glycolytic energy rather than oxidative phosphorylation, even under conditions of sufficient oxygen. Therefore, targeting metabolic enzymes is an effective strategy to overcome therapeutic resistance.

MATERIALS AND METHODS

We explored the differential expression and growth-promoting function of MDH2 by immunohistochemistry and immunoblotting experiments in lung cancer patients and lung cancer cells. Pentose phosphate pathway-related phenotypes (including ROS levels, NADPH levels, and DNA synthesis) were detected intracellularly, and the interaction of malate and proteinase 6PGD was detected in vitro. In vivo experiments using implanted xenograft mouse models to explore the growth inhibitory effect and pro-chemotherapeutic function of dimethyl malate (DMM) on lung cancer.

RESULTS

We found that the expression of malate dehydrogenase (MDH2) in the tricarboxylic acid cycle (TCA cycle) was increased in lung cancer. Biological function enrichment analysis revealed that MDH2 not only promoted oxidative phosphorylation, but also promoted the pentose phosphate pathway (PPP pathway). Mechanistically, it was found that malate, the substrate of MDH2, can bind to the PPP pathway metabolic enzyme 6PGD, inhibit its activity, reduce the generation of NADPH, and block DNA synthesis. More importantly, DMM can improve the sensitivity of lung cancer to the clinical drug cisplatin.

CONCLUSION

We have identified malate as a natural inhibitor of 6PGD, which will provide new leads for the development of 6PGD inhibitors. In addition, the metabolic enzyme MDH2 and the metabolite malate may provide a backup option for cells to inhibit their own carcinogenesis, as the accumulated malate targets 6PGD to block the PPP pathway and inhibit cell cycle progression.

KAT2A changes the function of endometrial stromal cells via regulating the succinylation of ENO1

Endometriosis is increasingly affecting women worldwide and research is focusing on identifying key targets in its pathogenesis. Changes in succinylation genes regulate the function of this protein and further influence the development of the disease. However, the role of succinylation genes in endometriosis is not clear from current studies. The expression of succinylation genes was determined in ectopic endometrium (EC) and ectopic patients with uterine fibroids (EN) by real-time quantitative PCR (qRT-PCR) and Western blot. Cell Counting Kit-8, transwell assays, and flow cytometry were used to assess endometrial stromal cells (ESCs) proliferation, apoptosis, migration, and invasion. KAT2A and ENO1 association was detected by qRT-PCR, immunofluorescence, and CoIP. We found that gene and protein levels of KAT2A were significantly increased in the EC group compared to EN group tissues. KAT2A silencing inhibited cell proliferation, migration, and invasion and promoted apoptosis. Western blot results showed that the expression of ENO1 and its succinylation was significantly upregulated in ECSc after KAT2A overexpression. CoIP results showed that KAT2A is positively bound to ENO1. Immunofluorescence also showed co-localized expression of KAT2A with ENO1. Furthermore, ENO1 overexpression reversed the effects of KAT2A silencing on the malignant behavior of ESCs. In summary, we found that succinylation of ENO1 mediated by KAT2A played a role in promoting the progression of endometriosis.

Overview of the development of protein arginine methyltransferase modulators: Achievements and future directions

Protein methylation is a post-translational modification (PTM) that organisms undergo. This process is considered a part of epigenetics research. In recent years, there has been an increasing interest in protein methylation, particularly histone methylation, as research has advanced. Methylation of histones is a dynamic process that is subject to fine control by histone methyltransferases and demethylases. In addition, many non-histone proteins also undergo methylation, and these modifications collectively regulate physiological phenomena, including RNA transcription, translation, signal transduction, DNA damage response, and cell cycle. Protein arginine methylation is a crucial aspect of protein methylation, which plays a significant role in regulating the cell cycle and repairing DNA. It is also linked to various diseases. Therefore, protein arginine methyltransferases (PRMTs) that are involved in this process have gained considerable attention as a potential therapeutic target for treating diseases. Several PRMT inhibitors are in phase I/II clinical trials. This paper aims to introduce the structure, biochemical functions, and bioactivity assays of PRMTs. Additionally, we will review the structure-function of currently popular PRMT inhibitors. Through the analysis of various data on known PRMT inhibitors, we hope to provide valuable assistance for future drug design and development.

Protein arginine methyltransferases (PRMTs): Orchestrators of cancer pathogenesis, immunotherapy dynamics, and drug resistance

Protein Arginine Methyltransferases (PRMTs) are a family of enzymes regulating protein arginine methylation, which is a post-translational modification crucial for various cellular processes. Recent studies have highlighted the mechanistic role of PRMTs in cancer pathogenesis, immunotherapy, and drug resistance. PRMTs are involved in diverse oncogenic processes, including cell proliferation, apoptosis, and metastasis. They exert their effects by methylation of histones, transcription factors, and other regulatory proteins, resulting in altered gene expression patterns. PRMT-mediated histone methylation can lead to aberrant chromatin remodeling and epigenetic changes that drive oncogenesis. Additionally, PRMTs can directly interact with key signaling pathways involved in cancer progression, such as the PI3K/Akt and MAPK pathways, thereby modulating cell survival and proliferation. In the context of cancer immunotherapy, PRMTs have emerged as critical regulators of immune responses. They modulate immune checkpoint molecules, including programmed cell death protein 1 (PD-1), through arginine methylation. Drug resistance is a significant challenge in cancer treatment, and PRMTs have been implicated in this phenomenon. PRMTs can contribute to drug resistance through multiple mechanisms, including the epigenetic regulation of drug efflux pumps, altered DNA damage repair, and modulation of cell survival pathways. In conclusion, PRMTs play critical roles in cancer pathogenesis, immunotherapy, and drug resistance. In this overview, we have endeavored to illuminate the mechanistic intricacies of PRMT-mediated processes. Shedding light on these aspects will offer valuable insights into the fundamental biology of cancer and establish PRMTs as promising therapeutic targets.

Small molecules targeting selected histone methyltransferases (HMTs) for cancer treatment: Current progress and novel strategies

Histone methyltransferases (HMTs) play a critical role in gene post-translational regulation and diverse physiological processes, and are implicated in a plethora of human diseases, especially cancer. Increasing evidences demonstrate that HMTs may serve as a potential therapeutic target for cancer treatment. Thus, the development of HMTs inhibitor have been pursued with steadily increasing interest over the past decade. However, the disadvantages such as insufficient clinical efficacy, moderate selectivity, and propensity for acquired resistance have hindered the development of conventional HMT inhibitors. New technologies and methods are imperative to enhance the anticancer activity of HMT inhibitors. In this review, we first review the structure and biological functions of the several essential HMTs, such as EZH2, G9a, PRMT5, and DOT1L. The internal relationship between these HMTs and cancer is also expounded. Next, we mainly focus on the latest progress in the development of HMT modulators encompassing dual-target inhibitors, targeted protein degraders and covalent inhibitors from perspectives such as rational design, pharmacodynamics, pharmacokinetics, and clinical status. Lastly, we also discuss the challenges and future directions for HMT-based drug discovery for cancer therapy.

PRMT6 Promotes the Immune Evasion of Gastric Cancer by Upregulating ANXA1

Gastric cancer is a most malignancy in digestive tract worldwide. This study aimed to investigate the roles of protein arginine methyltransferase 6 (PRMT6) in gastric cancer. Immunohistochemistry was performed to detect PRMT6 expression in gastric tumors. Real-time transcriptase-quantitative polymerase chain reaction (RT-qPCR) was used to detected mRNA levels. Protein expression was determined using western blot. Gastric cancer cells were co-cultured with CD8+ T cells. Colony formation assay was performed to detect cell proliferation. Flow cytometry was performed to determine CD8+ T cell function and tumor cell apoptosis. PRMT6 was overexpressed in gastric tumors. High level of PRMT6 predicted poor outcomes of gastric cancer patients and inhibition of CD8+ T cell infiltration. PRMT6 promoted proliferation of CD8+ T cells and enhanced its tumor killing ability. Moreover, PRMT6 upregulated annexin A1 (ANXA1) and promoted ANXA1 protein stability. ANXA1 overexpression suppressed the proliferation of CD8+ T cells and promoted tumor cell survival. PRMT6 functions as an oncogene in gastric cancer. PRMT6-mediated protein stability inhibits the infiltration of CD8+ T cells, resulting in immune evasion of gastric cancer. The PRMT6-ANXA1 may be a promising strategy for gastric cancer.

A state-of-art of underlying molecular mechanisms and pharmacological interventions/nanotherapeutics for cisplatin resistance in gastric cancer

The fourth common reason of death among patients is gastric cancer (GC) and it is a dominant tumor type in Ease Asia. One of the problems in GC therapy is chemoresistance. Cisplatin (CP) is a platinum compound that causes DNA damage in reducing tumor progression and viability of cancer cells. However, due to hyperactivation of drug efflux pumps, dysregulation of genes and interactions in tumor microenvironment, tumor cells can develop resistance to CP chemotherapy. The current review focuses on the CP resistance emergence in GC cells with emphasizing on molecular pathways, pharmacological compounds for reversing chemoresistance and the role of nanostructures. Changes in cell death mechanisms such as upregulation of pro-survival autophagy can prevent CP-mediated apoptosis that results in drug resistance. Moreover, increase in metastasis via EMT induction induces CP resistance. Dysregulation of molecular pathways such as PTEN, PI3K/Akt, Nrf2 and others result in changes in CP response of GC cells. Non-coding RNAs determine CP response of GC cells and application of pharmacological compounds with activity distinct of CP can result in sensitivity in tumor cells. Due to efficacy of exosomes in transferring bioactive molecules such as RNA and DNA molecules among GC cells, exosomes can also result in CP resistance. One of the newest progresses in overcoming CP resistance in GC is application of nanoplatforms for delivery of CP in GC therapy that they can increase accumulation of CP at tumor site and by suppressing carcinogenic factors and overcoming biological barriers, they increase CP toxicity on cancer cells.

HOXA1 promotes aerobic glycolysis and cancer progression in cervical cancer

As a hallmark for cancer, aerobic glycolysis, also known as the Warburg effect contributes to tumor progression. However, the roles of aerobic glycolysis on cervical cancer remain elusive. In this work, we identified transcription factor HOXA1 as a novel regulator of aerobic glycolysis. High expression of HOXA1 is closely associated with poor outcome of patients. And, altered HOXA1 expression enhance or reduce aerobic glycolysis and progression in cervical cancer. Mechanistically, HOXA1 directly regulates the transcriptional activity of ENO1 and PGK1, thus induce glycolysis and promote cancer progression. Moreover, therapeutic knockdown of HOXA1 results in reduce aerobic glycolysis and inhibits cervical cancer progression in vivo and in vitro. In conclusion, these data indicate a therapeutic role of HOXA1 inhibits aerobic glycolysis and cervical cancer progression.

γ-enolase (ENO2) is methylated at the Nτ position of His-190 among enolase isozymes

Protein methylation is mainly observed in lysine, arginine and histidine residues. Histidine methylation occurs at one of two different nitrogen atoms of the imidazole ring, producing Nτ-methylhistidine and Nπ-methylhistidine, and it has recently attracted attention with the identification of SETD3, METTL18 and METTL9 as catalytic enzymes in mammals. Although accumulating evidence had suggested the presence of more than 100 proteins containing methylated histidine residues in cells, much less information has been known regarding histidine-methylated proteins than lysine- and arginine-methylated ones, because no method has been developed to identify substrates for histidine methylation. Here, we established a method to screen novel target proteins for histidine methylation, using biochemical protein fractionation combined with the quantification of methylhistidine by LC-MS/MS. Interestingly, the differential distribution pattern of Nτ-methylated proteins was found between the brain and skeletal muscle, and identified γ-enolase where the His-190 at the Nτ position is methylated in mouse brain. Finally, in silico structural prediction and biochemical analysis showed that the His-190 in γ-enolase is involved in the intermolecular homodimeric formation and enzymatic activity. In the present study, we provide a new methodology to find histidine-methylated proteins in vivo and suggest an insight into the importance of histidine methylation.