PRMT7 contributes to the metastasis phenotype in human non-small-cell lung cancer cells possibly through the interaction with HSPA5 and EEF2

Development of Novel PRMT7 Inhibitors for the Treatment of Prostate Cancer

Prostate cancer (PCa) remains a prevalent malignancy in men and warrants novel and efficacious therapy. Protein arginine methyltransferase 7 (PRMT7) has been recently identified as a promising target for PCa treatment, however, the development of efficacious PRMT7 inhibitors is limited. Herein, we reported an effective and selective PRMT7 inhibitor, A33, which was obtained through structural optimization and exhibited potent anti-PCa efficacy in vitro and in vivo. A33 significantly inhibited the proliferation, colony formation, migration, and invasion of PCa cells and induced substantial cell cycle arrest and apoptosis. Mechanistically, A33 decreased the monomethylarginine level in PCa cells, regulated tumor metastasis-, proliferation-, and apoptosis-associated proteins, and enhanced antitumor innate immunity by targeting PRMT7. More importantly, A33 exhibited low toxicity and effectively suppressed PCa tumor growth in the DU-145 xenograft tumor model. Collectively, this study provides a novel potent PRMT7 inhibitor for further anti-PCa drug discovery.

PRMT7 Inhibitor SGC3027 Enhances Radiotherapy Efficacy via Activating ATM Kinase in Non-Small Cell Lung Carcinoma

Non-small-cell lung cancer (NSCLC) is the leading cause of tumor-related death in humans. Radiotherapy is a crucial strategy for NSCLC treatment, although its effectiveness is limited by the radio-resistance of tumor cells. Our current research finds that the protein arginine methyltransferase 7 (PRMT7) is upregulated in NSCLC and correlates with poor prognosis. Pharmacological inhibition of PRMT7 by SGC3027, a specific small-molecule PRMT7 inhibitor, suppresses the proliferation, migration and invasion of NSCLC. Combining irradiation with SGC3027 strengthens the impact of irradiation on the biological behaviors of NSCLC cells. We also find that SGC3027 specifically activates ATM kinase and its downstream cell cycle checkpoint kinases to enhance radiobiological response in NSCLC. These findings underscore the promising therapeutic potential of PRMT7 inhibitors as well as combining PRMT7 inhibition with irradiation exposure for effective NSCLC therapies.

METTL3/IGF2BP1 promotes the development of triple-negative breast cancer by mediating m6A methylation modification of PRMT7

BACKGROUND

PRMT7 is upregulated in breast cancer and promotes tumor metastasis. Here we aimed to explore the function and mechanism of PRMT7 in triple-negative breast cancer (TNBC).

METHODS

The expression of PRMT7, METTL3 and IGF2BP1 was detected by immunohistochemistry (IHC), qRT-PCR and western blot. Cell viability and proliferation were measured using MTT and EdU assay. Flow cytometry and TUNEL assays were used to evaluate apoptosis. Invasion and migration were assessed by transwell and wound healing assays, respectively. Glucose consumption and lactate production were measured to assess glycolysis. In addition, the interaction between METTL3 and PRMT was verified by methylated RNA immunoprecipitation. The roles of METTL3 and PRMT in vivo were investigated through a xenograft model.

RESULTS

PRMT7 was upregulated in TNBC tissues and cells, and the knockdown of PRMT7 inhibited cell proliferation, invasion, migration and glycolysis, but induced apoptosis in TNBC cells. METTL3/IGF2BP1 enhanced PRMT7 expression by mediating the m6A methylation modification of PRMT7. Besides, METTL3 knockdown suppressed the progression of TNBC cells and regulated the WNT/β-catenin pathway via PRMT7. Moreover, silencing METTL3 restrained TNBC tumor growth in vivo through regulating PRMT7.

CONCLUSION

METTL3/IGF2BP1 facilitates the progression of TNBC by mediating m6A methylation modification of PRMT7.

Biomedical effects of protein arginine methyltransferase inhibitors

Protein arginine methyltransferases (PRMTs) are enzymes that catalyze the methylation of arginine residues in eukaryotic proteins, playing critical roles in modulating diverse cellular processes. The importance of PRMTs in the incidence and progression of a wide range of diseases, particularly cancers, such as breast, liver, lung, colorectal cancer, lymphoma, leukemia, and acute myeloid leukemia is increasingly recognized. This underscores the critical need for the development of effective PRMT inhibitors as therapeutic intervention. The field of PRMT inhibitors is in the rapidly growing phase and it is necessary to conduct a summative review of how the so-far developed inhibitors impact PRMT functions and cellular physiology. Our review aims to summarize molecular action mechanisms of these PRMT inhibitors and particularly elaborate their triggered biomedical effects. We describe the cellular phenotype consequences of select PRMT inhibitors across various disease models, thereby providing an understanding of the pharmacological mechanisms underpinning PRMT inhibition. The promising effects of PRMT5 inhibitors in targeted therapy of methylthioadenosine phosphorylase-deleted cancers are particularly highlighted. At last, we provide a perspective on the challenges and further opportunities of developing and applying novel PRMT inhibitors for clinical advancement.

PRMT7 in cancer: Structure, effects, and therapeutic potentials

Protein arginine methyltransferase 7 (PRMT7), a type III methyltransferase responsible solely for arginine mono-methylation, plays a critical role in numerous physiological and pathological processes. Recent studies have highlighted its aberrant expression or mutation in various cancers, implicating it in tumorigenesis, cancer progression, and drug resistance. Consequently, PRMT7 has emerged as a promising target for cancer diagnosis and therapeutic intervention. In this review, we present an overview of the molecular structure of PRMT7, discuss its roles and mechanisms in different cancer types, and analyze the binding modes and structure-activity relationships of reported PRMT7 inhibitors. Furthermore, we identify the challenges encountered in functional exploration and drug development targeting PRMT7, propose potential solutions to these challenges, and outline future directions for the development of PRMT7 inhibitors to inform future drug discovery efforts.

Protein arginine methyltransferase 7 modulators in disease therapy: Current progress and emerged opportunity

Protein arginine methyltransferase 7 (PRMT7) is an essential epigenetic and post-translational regulator in eukaryotic organisms. Dysregulation of PRMT7 is intimately related to multiple types of human diseases, particularly cancer. In addition, PRMT7 exerts multiple effects on cellular processes such as growth, migration, invasion, apoptosis, and drug resistance in various cancers, making it as a promising target for anti-tumor therapeutics. In this review, we initially provide an overview of the structure and biological functions of PRMT7, along with its association with diseases. Subsequently, we summarized the PRMT inhibitors in clinical trials and the co-crystal structural of PRMT7 inhibitors. Moreover, we also focus on recent progress in the design and development of modulators targeting PRMT7, including isoform-selective and non-selective PRMT7 inhibitors, and the dual-target inhibitors based on PRMT7, 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 PRMT7 targeting drug discovery in cancer therapy.

Elongation factor 2 in cancer: a promising therapeutic target in protein translation

Aberrant elongation of proteins can lead to the activation of oncogenic signaling pathways, resulting in the dysregulation of oncogenic signaling pathways. Eukaryotic elongation factor 2 (eEF2) is an essential regulator of protein synthesis that precisely elongates nascent peptides in the protein elongation process. Although studies have linked aberrant eEF2 expression to various cancers, research has primarily focused on its structure, highlighting a need for deeper exploration into its molecular functions. In this review, recent advancements in the structure, guanosine triphosphatase (GTPase) activity, posttranslational modifications, regulatory factors, and inhibitors of eEF2 are summarized. These findings provide a comprehensive cognition on the critical role of eEF2 and its potential as a therapeutic target in cancer. Furthermore, this review highlights important unanswered questions that warrant investigation in future research.

The role of histone post-translational modifications in cancer and cancer immunity: functions, mechanisms and therapeutic implications

Histones play crucial roles in both promoting and repressing gene expression, primarily regulated through post-translational modifications (PTMs) at specific amino acid residues. Histone PTMs, including methylation, acetylation, ubiquitination, phosphorylation, lactylation, butyrylation, and propionylation, act as important epigenetic markers. These modifications influence not only chromatin compaction but also gene expression. Their importance extends to the treatment and prevention of various human diseases, particularly cancer, due to their involvement in key cellular processes. Abnormal histone modifications and the enzymes responsible for these alterations often serve as critical drivers in tumor cell proliferation, invasion, apoptosis, and stemness. This review introduces key histone PTMs and the enzymes responsible for these modifications, examining their impact on tumorigenesis and cancer progression. Furthermore, it explores therapeutic strategies targeting histone PTMs and offers recommendations for identifying new potential therapeutic targets.

Multi-omics with dynamic network biomarker algorithm prefigures organ-specific metastasis of lung adenocarcinoma

Efficacious strategies for early detection of lung cancer metastasis are of significance for improving the survival of lung cancer patients. Here we show the marker genes and serum secretome foreshadowing the lung cancer site-specific metastasis through dynamic network biomarker (DNB) algorithm, utilizing two clinical cohorts of four major types of lung cancer distant metastases, with single-cell RNA sequencing (scRNA-seq) of primary lesions and liquid chromatography-mass spectrometry data of sera. Also, we locate the intermediate status of cancer cells, along with its gene signatures, in each metastatic state trajectory that cancer cells at this stage still have no specific organotropism. Furthermore, an integrated neural network model based on the filtered scRNA-seq data is successfully constructed and validated to predict the metastatic state trajectory of cancer cells. Overall, our study provides an insight to locate the pre-metastasis status of lung cancer and primarily examines its clinical application value, contributing to the early detection of lung cancer metastasis in a more feasible and efficacious way.

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.

Energy metabolism as the hub of advanced non-small cell lung cancer management: a comprehensive view in the framework of predictive, preventive, and personalized medicine

Energy metabolism is a hub of governing all processes at cellular and organismal levels such as, on one hand, reparable vs. irreparable cell damage, cell fate (proliferation, survival, apoptosis, malignant transformation etc.), and, on the other hand, carcinogenesis, tumor development, progression and metastazing versus anti-cancer protection and cure. The orchestrator is the mitochondria who produce, store and invest energy, conduct intracellular and systemically relevant signals decisive for internal and environmental stress adaptation, and coordinate corresponding processes at cellular and organismal levels. Consequently, the quality of mitochondrial health and homeostasis is a reliable target for health risk assessment at the stage of reversible damage to the health followed by cost-effective personalized protection against health-to-disease transition as well as for targeted protection against the disease progression (secondary care of cancer patients against growing primary tumors and metastatic disease). The energy reprogramming of non-small cell lung cancer (NSCLC) attracts particular attention as clinically relevant and instrumental for the paradigm change from reactive medical services to predictive, preventive and personalized medicine (3PM). This article provides a detailed overview towards mechanisms and biological pathways involving metabolic reprogramming (MR) with respect to inhibiting the synthesis of biomolecules and blocking common NSCLC metabolic pathways as anti-NSCLC therapeutic strategies. For instance, mitophagy recycles macromolecules to yield mitochondrial substrates for energy homeostasis and nucleotide synthesis. Histone modification and DNA methylation can predict the onset of diseases, and plasma C7 analysis is an efficient medical service potentially resulting in an optimized healthcare economy in corresponding areas. The MEMP scoring provides the guidance for immunotherapy, prognostic assessment, and anti-cancer drug development. Metabolite sensing mechanisms of nutrients and their derivatives are potential MR-related therapy in NSCLC. Moreover, miR-495-3p reprogramming of sphingolipid rheostat by targeting Sphk1, 22/FOXM1 axis regulation, and A2 receptor antagonist are highly promising therapy strategies. TFEB as a biomarker in predicting immune checkpoint blockade and redox-related lncRNA prognostic signature (redox-LPS) are considered reliable predictive approaches. Finally, exemplified in this article metabolic phenotyping is instrumental for innovative population screening, health risk assessment, predictive multi-level diagnostics, targeted prevention, and treatment algorithms tailored to personalized patient profiles-all are essential pillars in the paradigm change from reactive medical services to 3PM approach in overall management of lung cancers. This article highlights the 3PM relevant innovation focused on energy metabolism as the hub to advance NSCLC management benefiting vulnerable subpopulations, affected patients, and healthcare at large.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00357-5.

CRISPR/Cas9 screenings unearth protein arginine methyltransferase 7 as a novel essential gene in prostate cancer metastasis

Due to the limited effectiveness of current treatments, the survival rate of patients with metastatic castration-resistant prostate cancer (mCRPC) is significantly reduced. Consequently, it is imperative to identify novel therapeutic targets for managing these patients. Since the invasive ability of cells is crucial for establishing and maintaining metastasis, the aim of this study was to identify the essential regulators of invasive abilities of mCRPC cells by conducting two independent high-throughput CRISPR/Cas9 screenings. Furthermore, some of the top hits were validated using siRNA technology, with protein arginine methyltransferase 7 (PRMT7) emerging as the most promising candidate. We demonstrated that its inhibition or depletion via genetic or pharmacological approaches significantly reduces invasive, migratory and proliferative abilities of mCRPC cells in vitro. Moreover, we confirmed that PRMT7 ablation reduces cell dissemination in chicken chorioallantoic membrane and mouse xenograft assays. Molecularly, PRMT7 reprograms the expression of several adhesion molecules by methylating various transcription factors, such as FoxK1, resulting in the loss of adhesion from the primary tumor and increased motility of mCRPC cells. Furthermore, PRMT7 higher expression correlates with tumor aggressivity and poor overall survival in prostate cancer patients. Thus, this study demonstrates that PRMT7 is a potential therapeutic target and potential biomarker for mPCa.

PRMT7-Dependent Transcriptional Activation of Hmgb2 Aggravates Severe Acute Pancreatitis by Promoting Acsl1-Induced Ferroptosis

Severe acute pancreatitis (SAP) is a highly fatal abdominal emergency, and its association with protein arginine methyltransferase 7 (PRMT7), the sole known type III enzyme responsible for the monomethylation of arginine residue, remains unexplored. In this study, we observe an increase in the PRMT7 levels in the pancreas of SAP mice and Cerulein-LPS-stimulated AR42J cells. Overexpression of Prmt7 exacerbated pancreatic damage in SAP, while the inhibition of PRMT7 improved SAP-induced pancreatic damage. Furthermore, PRMT7 overexpression promoted inflammation, oxidative stress, and ferroptosis during SAP. Mechanically, PRMT7 catalyzed monomethylation at histone H4 arginine 3 (H4R3me1) at the promoter region of high mobility group proteins 2 (HMGB2), thereby enhancing its transcriptional activity. Subsequently, HMGB2 facilitated Acyl CoA synthase long-chain family member 1 (ACSL1) transcription by binding to its promoter region, resulting in the activation of ferroptosis. Inhibition of PRMT7 effectively alleviated ferroptosis in Cerulein-LPS-induced AR42J cells by suppressing the HMGB2-ACSL1 pathway. Overall, our study reveals that PRMT7 plays a crucial role in promoting SAP through its regulation of the HMGB2-ACSL1 pathway to accelerate ferroptosis.

Fasting regulates mitochondrial function through lncRNA PRKCQ-AS1-mediated IGF2BPs in papillary thyroid carcinoma

Recurring evidence suggests that fasting has extensive antitumor effects in various cancers, including papillary thyroid carcinoma (PTC). However, the underlying mechanism of this relationship with PTC is unknown. In this study, we study the effect of fasting on glycolysis and mitochondrial function in PTC. We find that fasting impairs glycolysis and reduces mitochondrial dysfunction in vitro and in vivo and also fasting in vitro and fasting mimicking diets (FMD) in vivo significantly increase the expression of lncRNA-protein kinase C theta antisense RNA 1 (PRKCQ-AS1), during the inhibition of TPC cell glycolysis and mitochondrial function. Moreover, lncRNA PRKCQ-AS1 was significantly lower in PTC tissues and cells. In addition, PRKCQ-AS1 overexpression increased PTC cell glycolysis and mitochondrial function; PRKCQ-AS1 knockdown has the opposite effect. On further mechanistic analysis, we identified that PRKCQ-AS1 physically interacts with IGF2BPs and enhances protein arginine methyltransferases 7 (PRMT7) mRNA, which is the key player in regulating glycolysis and mitochondrial function in PTC. Hence, PRKCQ-AS1 inhibits tumor growth while regulating glycolysis and mitochondrial functions via IGF2BPs/PRMT7 signaling. These results indicate that lncRNA PRKCQ-AS1 is a key downstream target of fasting and is involved in PTC metabolic reprogramming. Further, the PRKCQ-AS1/IGF2BPs/PRMT7 axis is an ideal therapeutic target for PTC diagnosis and treatment.

The protein arginine methyltransferase family (PRMTs) regulates metastases in various tumors: From experimental study to clinical application

Tumor metastasis is the leading cause of mortality among advanced cancer patients. Understanding its mechanisms and treatment strategies is vital for clinical application. Arginine methylation, a post-translational modification catalyzed by protein arginine methyltransferases (PRMTs), is implicated in diverse physiological processes and disease progressions. Previous research has demonstrated PRMTs' involvement in tumor occurrence, progression, and metastasis. This review offers a comprehensive summary of the relationship between PRMTs, prognosis, and metastasis in various cancers. Our focus centers on elucidating the molecular mechanisms through which PRMTs regulate tumor metastasis. We also discuss relevant clinical trials and effective PRMT inhibitors, including chemical compounds, long non-coding RNA (lncRNA), micro-RNA (miRNA), and nanomaterials, for treating tumor metastasis. While a few studies present conflicting results, the overall trajectory suggests that inhibiting arginine methylation exhibits promise in curtailing tumor metastasis across various cancers. Nonetheless, the underlying mechanisms and molecular interactions are diverse. The development of inhibitors targeting arginine methylation, along with the progression of clinical trials, holds substantial potential in the field of tumor metastasis, meriting sustained attention.

PRMT7 Inhibits the Proliferation and Migration of Gastric Cancer Cells by Suppressing the PI3K/AKT Pathway via PTEN

Protein arginine methyltransferase 7 (PRMT7) plays a crucial role in tumor occurrence and development; however, its expression pattern, biological function, and specific mechanism in gastric cancer (GC) remain poorly defined. The present study aimed to investigate the role of PRMT7 during GC carcinogenesis and its underlying mechanism. We found that PRMT7 is expressed at low levels in GC tissues, and this low expression is associated with tumor size, differentiation degree, lymph node metastasis, and TNM stage. Functionally, PRMT7 inhibits GC cell proliferation and migration. Mechanistically, PRMT7 induces PTEN expression and suppresses the downstream PI3K/AKT signaling cascade. Finally, we confirmed that PRMT7 interacts with PTEN protein and promotes PTEN arginine methylation. Taken together, our findings suggest that PRMT7 can inhibit PI3K/AKT signaling pathway activation by regulating PTEN, thereby inhibiting GC cell proliferation and migration. PRMT7 may be a promising therapeutic target for the prevention of GC.

Toosendanin targeting eEF2 impedes Topoisomerase I & II protein translation to suppress esophageal squamous cell carcinoma growth

BACKGROUND

Although molecular targets such as HER2, TP53 and PIK3CA have been widely studied in esophageal cancer, few of them were successfully applied for clinical treatment. Therefore, it is urgent to discover novel actionable targets and inhibitors. Eukaryotic translational elongation factor 2 (eEF2) is reported to be highly expressed in various cancers. However, its contribution to the maintenance and progression of cancer has not been fully clarified.

METHODS

In the present study, we utilized tissue array to evaluate eEF2 protein expression and clinical significance in esophageal squamous cell carcinoma (ESCC). Next, we performed knockdown, overexpression, RNA-binding protein immunoprecipitation (RIP) sequence, and nascent protein synthesis assays to explore the molecular function of eEF2. Furthermore, we utilized compound screening, Surface Plasmon Resonance (SPR), Isothermal Titration Calorimetry (ITC) assay, cell proliferation and Patient derived xenograft (PDX) mouse model assays to discover an eEF2 inhibitor and assess its effects on ESCC growth.

RESULTS

We found that eEF2 were highly expressed in ESCC and negatively associated with the prognosis of ESCC patients. Knocking down of eEF2 suppressed the cell proliferation and colony formation of ESCC. eEF2 bond with the mRNA of Topoisomerase II (TOP1) and Topoisomerase II (TOP2) and enhanced the protein biosynthesis of TOP1 and TOP2. We also identified Toosendanin was a novel inhibitor of eEF2 and Toosendanin inhibited the growth of ESCC in vitro and in vivo.

CONCLUSIONS

Our findings show that Toosendanin treatment suppresses ESCC growth through targeting eEF2 and regulating downstream TOP1 and TOP2 biosynthesis. eEF2 could be supplied as a potential therapeutic target in the further clinical studies.

Elucidating the role of PRMTs in prostate cancer using open access databases and a patient cohort dataset

Protein arginine methylation is an understudied epigenetic mechanism catalyzed by enzymes known as Protein Methyltransferases of Arginine (PRMTs), while the opposite reaction is performed by Jumonji domain- containing protein 6 (JMJD6). There is increasing evidence that PRMTs are deregulated in prostate cancer (PCa). In this study, the expression of two PRMT members, PRMT2 and PRMT7 as well as JMJD6, a demethylase, was analyzed in PCa. Initially, we retrieved data from The Cancer Genome Atlas (TCGA) project and the Gene Expression Omnibus (GEO) database to explore the differential expression of various PRMT family members in patients with PCa and then applied immunohistochemistry in a patient cohort across the spectrum of PCa, including non-neoplastic prostate tissue and lymph node metastatic foci. The results from the TCGA analysis revealed that PRMT7, PRMT6 and PRMT3 expression increased while PRMT2, PRMT9 and JMJD6 levels decreased in the tumor compared to non-neoplastic prostate. Results from the GEO datasets were similar, albeit not identical with the TCGA results, with PRMT7 and PRMT3 being upregulated and PRMT2 and JMJD6 being downregulated in the tumor compared to non-neoplastic tissue in some of them. In addition, PRMT7 levels decreased with stage and grade progression in the TCGA analysis. In the patient cohort, both PRMTs and JMJD6 were overexpressed in PCa compared to non-neoplastic tissue, and nuclear PRMT2 and JMJD6 were upregulated in lymph node metastasis, too. PRMT7 and JMJD6 expression were upregulated with the progression of stage and JMJD6 was also increased with the elevation of grade. After androgen ablation therapy, nuclear expression of PRMT7 and JMJD6 were elevated compared to untreated tumors. PRMT2, PRMT7 and JMD6 were also correlated with markers of EMT and cell cycle regulators. Finally, our findings indicate that PRMTs and JMJD6 are involved in prostate cancer progression and revealed a potential interplay of PRMTs with EMT mediators, underscoring the need for therapeutic targeting of arginine methylation in prostate cancer.

Protein arginine methyltransferases in renal development, injury, repair, and fibrosis

Protein arginine methyltransferases (PRMTs) methylate a range of histone and non-histone substrates and participate in multiple biological processes by regulating gene transcription and post-translational modifications. To date, most studies on PRMTs have focused on their roles in tumors and in the physiological and pathological conditions of other organs. Emerging evidence indicates that PRMTs are expressed in the kidney and contribute to renal development, injury, repair, and fibrosis. In this review, we summarize the role and the mechanisms of PRMTs in regulating these renal processes and provide a perspective for future clinical applications.

A pan-cancer-bioinformatic-based literature review of TRPM7 in cancers

TRPM7, a divalent cation-selective channel with kinase domains, has been widely reported to potentially affect cancers. In this study, we conducted multiple bioinformatic analyses based on open databases and reviewed articles that provided evidence for the effects of TRPM7 on cancers. The purposes of this paper are 1) to provide a pan-cancer overview of TRPM7 in cancers; 2) to summarize evidence of TRPM7 effects on cancers; 3) to identify potential future studies of TRPM7 in cancer. Bioinformatics analysis revealed that no cancer-related TRPM7 mutation was found. TRPM7 is aberrantly expressed in most cancer types but the cancer-noncancer expression pattern varies across cancer types. TRPM7 was not associated with survival, TMB, or cancer stemness in most cancer types. TRPM7 affected drug sensitivity and tumor immunity in some cancer types. The in vitro evidence, preclinical in vivo evidence, and clinical evidence for TRPM7 effects on cancers as well as TRPM7 kinase substrate and TRPM7-targeting drugs associated with cancers were summarized to facilitate comparison. We matched the bioinformatics evidence to literature evidence, thereby unveiling potential avenues for future investigation of TRPM7 in cancers. We believe that this paper will help orient research toward important and relevant aspects of the role of TRPM7 in cancers.

Prmt7 Downregulation in Mouse Spermatogonia Functions through miR-877-3p/Col6a3

Protein arginine methyltransferases 7 (Prmt7) is expressed in male germ cells, including primordial germ cells, gonocytes, and spermatogonia. Our previous study demonstrated that Prmt7 downregulation reduced the proliferation of GC-1 cells (a cell line of mouse immortalized spermatogonia). However, how Prmt7 regulates spermatogonial proliferation through miRNA and the target gene remains elusive. Here, we experimentally reduced the Prmt7 expression in the GC-1 cells and subjected them to miRNA sequencing to explore the miRNA profile and its Prmt7-responsive members. In total, 48 differentially expressed miRNAs (DEmiRNAs), including 36 upregulated and 12 downregulated miRNAs, were identified. After verifying the validity of sequencing results through qRT-PCR assays in randomly selected DEmiRNAs, we predicted the target genes of these DEmiRNAs. Next, we combined DEmiRNA target genes and previously identified differentially expressed genes between Prmt7 knockdown and control groups of GC-1 cells, which resulted in seven miRNA/target gene pairs. Among these miRNA/target gene pairs, we further detected the expression of Col6a3 (collagen type VI alpha 3) as the target gene of mmu-miR-877-3p. The results suggested that Prmt7 downregulation in mouse spermatogonia might function through miR-877-3p/Col6a3. Overall, these findings provide new insights into the role of Prmt7 in male germ cell development through miRNA and target genes.

Circ_0039960 regulates growth and Warburg effect of breast cancer cells via modulating miR-1178/PRMT7 axis

BACKGROUND

Breast cancer (BC) is a serious threat to women's life and healthy. Increasing evidence indicated that blocking Warburg effect could attenuate the development of BC. Circular RNAs (circRNAs) has been found to be dysregulated in various carcinomas, including BC. Our study aims to illustrate the role and regulatory mechanism of circ_0039960 in BC development.

METHODS

RT-qPCR and western blotting were utilized to evaluate the expression of circ_0039960 in tissues recruited from 32 cases of BC patients and also BC cell lines. Circ_0039960 shRNA was transfected into cells to explore its function on cell processes. CCK-8, flow cytometry and ELISA were used to measure cell viability, cell cycle and apoptosis. Warburg effect was detected by using commercial kits. Besides, bioinformatic prediction, RIP and luciferase reporter assays were performed to validate the interactions between circ_0039960, miR-1178 and PRMT7.

RESULTS

The results showed that circ_0039960 and PRMT7 were both up-regulated, while miR-1178 was down-regulated, in BC tissues and cells. Silencing circ_0039960 effectively inhibited cell viability and Warburg effect of BC cells, also, induced cell cycle arrest and apoptosis. Moreover, we validated that circ_0039960 positively mediated PRMT7 expression via directly targeting to miR-1178. The inhibition of miR-1178 and overexpression of PRMT7 reversed the effect of circ_0039960 knockdown on BC cell growth and Warburg effect.

CONCLUSION

In general, our research demonstrated that circ_0039960 regulates cell growth and Warburg effect in BC cells via miR-1178/PRMT7 axis. This may provide new evidence for the exploration of BC diagnostic and therapeutic targets.

Arginine Methyltransferase PRMT7 Deregulates Expression of RUNX1 Target Genes in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with no well-established prognostic biomarkers. We examined the expression of protein arginine methyltransferases across hematological malignancies and discovered high levels of PRMT7 mRNA in T-ALL, particularly in the mature subtypes of T-ALL. The genetic deletion of PRMT7 by CRISPR-Cas9 reduced the colony formation of T-ALL cells and changed arginine monomethylation patterns in protein complexes associated with the RNA and DNA processing and the T-ALL pathogenesis. Among them was RUNX1, whose target gene expression was consequently deregulated. These results suggest that PRMT7 plays an active role in the pathogenesis of T-ALL.

Exploring Methods of Targeting Histone Methyltransferases and Their Applications in Cancer Therapeutics

Histone methyltransferases (HMTs) are enzymes that catalyze the methylation of lysine or arginine residues of histone proteins, a key post-translational modification (PTM). Aberrant expression or activity of these enzymes can lead to abnormal histone methylation of cancer-related genes and thus promote tumorigenesis. Histone methyltransferases have been implicated in chemotherapeutic resistance and immune stimulation, making these enzymes potential therapeutic targets of interest, and chemically targeting these proteins provides an avenue for novel drug development in cancer therapy. This Review aims to discuss the evolution of chemical approaches that have emerged in the past five years to design probes targeting these enzymes, including inhibition through noncovalent inhibitors, covalent inhibitors, and targeted protein degradation through proteolysis targeting chimeras (PROTACs). This Review also highlights how these compounds have been used to study the myriad of HMT functions in cancer progression and treatment response. The recent advancement of some of these drugs into human clinical investigation and even to regulatory approval highlights HMTs as a promising class of targets for chemical intervention and novel therapy development.

An enhancer variant at 16q22.1 predisposes to hepatocellular carcinoma via regulating PRMT7 expression

Most cancer causal variants are found in gene regulatory elements, e.g., enhancers. However, enhancer variants predisposing to hepatocellular carcinoma (HCC) remain unreported. Here we conduct a genome-wide survey of HCC-susceptible enhancer variants through a three-stage association study in 11,958 individuals and identify rs73613962 (T > G) within the intronic region of PRMT7 at 16q22.1 as a susceptibility locus of HCC (OR = 1.41, P = 6.02 × 10-10). An enhancer dual-luciferase assay indicates that the rs73613962-harboring region has allele-specific enhancer activity. CRISPR-Cas9/dCas9 experiments further support the enhancer activity of this region to regulate PRMT7 expression. Mechanistically, transcription factor HNF4A binds to this enhancer region, with preference to the risk allele G, to promote PRMT7 expression. PRMT7 upregulation contributes to in vitro, in vivo, and clinical HCC-associated phenotypes, possibly by affecting the p53 signaling pathway. This concept of HCC pathogenesis may open a promising window for HCC prevention/treatment.

The Emerging Role of PRMT6 in Cancer

Protein arginine methyltransferase 6 (PRMT6) is a type I PRMT that is involved in epigenetic regulation of gene expression through methylating histone or non-histone proteins, and other processes such as alternative splicing, DNA repair, cell proliferation and senescence, and cell signaling. In addition, PRMT6 also plays different roles in various cancers via influencing cell growth, migration, invasion, apoptosis, and drug resistant, which make PRMT6 an anti-tumor therapeutic target for a variety of cancers. As a result, many PRMT6 inhibitors are being utilized to explore their efficacy as potential drugs for various cancers. In this review, we summarize the current knowledge on the function and structure of PRMT6. At the same time, we highlight the role of PRMT6 in different cancers, including the differentiation of its promotive or inhibitory effects and the underlying mechanisms. Apart from the above, current research progress and the potential mechanisms of PRMT6 behind them were also summarized.

PRMT7: A Pivotal Arginine Methyltransferase in Stem Cells and Development

Protein arginine methylation is a posttranslational modification catalyzed by protein arginine methyltransferases (PRMTs), which play critical roles in many biological processes. To date, nine PRMT family members, namely, PRMT1, 2, 3, 4, 5, 6, 7, 8, and 9, have been identified in mammals. Among them, PRMT7 is a type III PRMT that can only catalyze the formation of monomethylarginine and plays pivotal roles in several kinds of stem cells. It has been reported that PRMT7 is closely associated with embryonic stem cells, induced pluripotent stem cells, muscle stem cells, and human cancer stem cells. PRMT7 deficiency or mutation led to severe developmental delay in mice and humans, which is possibly due to its crucial functions in stem cells. Here, we surveyed and summarized the studies on PRMT7 in stem cells and development in mice and humans and herein provide a discussion of the underlying molecular mechanisms. Furthermore, we also discuss the roles of PRMT7 in cancer, adipogenesis, male reproduction, cellular stress, and cellular senescence, as well as the future perspectives of PRMT7-related studies. Overall, PRMT7 mediates the proliferation and differentiation of stem cells. Deficiency or mutation of PRMT7 causes developmental delay, including defects in skeletal muscle, bone, adipose tissues, neuron, and male reproduction. A better understanding of the roles of PRMT7 in stem cells and development as well as the underlying mechanisms will provide information for the development of strategies for in-depth research of PRMT7 and stem cells as well as their applications in life sciences and medicine.

PRMT7 targets of Foxm1 controls alveolar myofibroblast proliferation and differentiation during alveologenesis

Although aberrant alveolar myofibroblasts (AMYFs) proliferation and differentiation are often associated with abnormal lung development and diseases, such as bronchopulmonary dysplasia (BPD), chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF), epigenetic mechanisms regulating proliferation and differentiation of AMYFs remain poorly understood. Protein arginine methyltransferase 7 (PRMT7) is the only reported type III enzyme responsible for monomethylation of arginine residue on both histone and nonhistone substrates. Here we provide evidence for PRMT7's function in regulating AMYFs proliferation and differentiation during lung alveologenesis. In PRMT7-deficient mice, we found reduced AMYFs proliferation and differentiation, abnormal elastin deposition, and failure of alveolar septum formation. We further shown that oncogene forkhead box M1 (Foxm1) is a direct target of PRMT7 and that PRMT7-catalyzed monomethylation at histone H4 arginine 3 (H4R3me1) directly associate with chromatin of Foxm1 to activate its transcription, and thereby regulate of cell cycle-related genes to inhibit AMYFs proliferation and differentiation. Overexpression of Foxm1 in isolated myofibroblasts (MYFs) significantly rescued PRMT7-deficiency-induced cell proliferation and differentiation defects. Thus, our results reveal a novel epigenetic mechanism through which PRMT7-mediated histone arginine monomethylation activates Foxm1 transcriptional expression to regulate AMYFs proliferation and differentiation during lung alveologenesis and may represent a potential target for intervention in pulmonary diseases.

Phosphoproteomics Identifies Significant Biomarkers Associated with the Proliferation and Metastasis of Prostate Cancer

The spider peptide toxins HNTX-III and JZTX-I are a specific inhibitor and activator of TTX-S VGSCs, respectively. They play important roles in regulating MAT-LyLu cell metastasis in prostate cancer. In order to identify key biomarkers involved in the regulation of MAT-LyLu cell metastasis, iTRAQ-based quantitative phosphoproteomics analysis was performed on cells treated with HNTX-III, JZTX-I and blank. A total of 554 unique phosphorylated proteins and 1779 distinct phosphorylated proteins were identified, while 55 and 36 phosphorylated proteins were identified as differentially expressed proteins in HNTX-III and JZTX-I treated groups compared with control groups. Multiple bioinformatics analysis based on quantitative phosphoproteomics data suggested that the differentially expressed phosphorylated proteins and peptides were significantly associated with the migration and invasion of prostate tumors. Specifically, the toxins HNTX-III and JZTX-I have opposite effects on tumor formation and metastasis by regulating the expression and phosphorylation level of causal proteins. Herein, we highlighted three key proteins EEF2, U2AF2 and FLNC which were down-regulated in HNTX-III treated cells and up-regulated in JZTX-I treated cells. They played significant roles in cancer related physiological and pathological processes. The differentially expressed phosphorylated proteins identified in this study may serve as potential biomarkers for precision medicine for prostate cancer in the near future.

Structure and Function of Protein Arginine Methyltransferase PRMT7

PRMT7 is a member of the protein arginine methyltransferase (PRMT) family, which methylates a diverse set of substrates. Arginine methylation as a posttranslational modification regulates protein-protein and protein-nucleic acid interactions, and as such, has been implicated in various biological functions. PRMT7 is a unique, evolutionarily conserved PRMT family member that catalyzes the mono-methylation of arginine. The structural features, functional aspects, and compounds that inhibit PRMT7 are discussed here. Several studies have identified physiological substrates of PRMT7 and investigated the substrate methylation outcomes which link PRMT7 activity to the stress response and RNA biology. PRMT7-driven substrate methylation further leads to the biological outcomes of gene expression regulation, cell stemness, stress response, and cancer-associated phenotypes such as cell migration. Furthermore, organismal level phenotypes of PRMT7 deficiency have uncovered roles in muscle cell physiology, B cell biology, immunity, and brain function. This rapidly growing information on PRMT7 function indicates the critical nature of context-dependent functions of PRMT7 and necessitates further investigation of the PRMT7 interaction partners and factors that control PRMT7 expression and levels. Thus, PRMT7 is an important cellular regulator of arginine methylation in health and disease.

The role of protein arginine methyltransferase 7 in human developmentally arrested embryos cultured in vitro

Human embryos of in vitro fertilization (IVF) are often susceptible to developmental arrest, which greatly reduces the efficiency of IVF treatment. In recent years, it has been found that protein arginine methyltransferase 7 (PRMT7) plays an important role in the process of early embryonic development. However, not much is known about the relationship between PRMT7 and developmentally arrested embryos. The role of PRMT7 in developmentally arrested embryos was thus investigated in this study. Discarded human embryos from IVF were collected for experimental materials. Quantitative real-time polymerase chain reaction (qRT-PCR) and confocal analyses were used to identify PRMT7 mRNA and protein levels in early embryos at different developmental stages, as well as changes in the methylation levels of H4R3me2s. Additionally, PRMT7 was knocked down in the developmentally arrested embryos to observe the further development of these embryos. Our results demonstrated that PRMT7 mRNA and protein levels in arrested embryos were significantly increased compared with those in control embryos; meanwhile, the methylation levels of H4R3me2s in arrested embryos were also increased significantly. Knockdown of PRMT7 could rescue partially developmentally arrested embryos, and even individual developmentally arrested embryos could develop into blastocysts. In conclusion, over-expression of PRMT7 disrupts the early embryo development process, leading to early embryos developmental arrest, but these developmentally arrested defects could be partially rescued by knockdown of the PRMT7 protein.

Protein arginine methylation: from enigmatic functions to therapeutic targeting

Protein arginine methyltransferases (PRMTs) are emerging as attractive therapeutic targets. PRMTs regulate transcription, splicing, RNA biology, the DNA damage response and cell metabolism; these fundamental processes are altered in many diseases. Mechanistically understanding how these enzymes fuel and sustain cancer cells, especially in specific metabolic contexts or in the presence of certain mutations, has provided the rationale for targeting them in oncology. Ongoing inhibitor development, facilitated by structural biology, has generated tool compounds for the majority of PRMTs and enabled clinical programmes for the most advanced oncology targets, PRMT1 and PRMT5. In-depth mechanistic investigations using genetic and chemical tools continue to delineate the roles of PRMTs in regulating immune cells and cancer cells, and cardiovascular and neuronal function, and determine which pathways involving PRMTs could be synergistically targeted in combination therapies for cancer. This research is enhancing our knowledge of the complex functions of arginine methylation, will guide future clinical development and could identify new clinical indications.

Protein arginine methyltransferases: promising targets for cancer therapy

Protein methylation, a post-translational modification (PTM), is observed in a wide variety of cell types from prokaryotes to eukaryotes. With recent and rapid advancements in epigenetic research, the importance of protein methylation has been highlighted. The methylation of histone proteins that contributes to the epigenetic histone code is not only dynamic but is also finely controlled by histone methyltransferases and demethylases, which are essential for the transcriptional regulation of genes. In addition, many nonhistone proteins are methylated, and these modifications govern a variety of cellular functions, including RNA processing, translation, signal transduction, DNA damage response, and the cell cycle. Recently, the importance of protein arginine methylation, especially in cell cycle regulation and DNA repair processes, has been noted. Since the dysregulation of protein arginine methylation is closely associated with cancer development, protein arginine methyltransferases (PRMTs) have garnered significant interest as novel targets for anticancer drug development. Indeed, several PRMT inhibitors are in phase 1/2 clinical trials. In this review, we discuss the biological functions of PRMTs in cancer and the current development status of PRMT inhibitors in cancer therapy.

MALAT1 Promotes Cell Tumorigenicity Through Regulating miR-515-5p/EEF2 Axis in Non-Small Cell Lung Cancer

Background

Previous studies suggested long noncoding RNA metastasis associated with lung adenocarcinoma transcript 1 (lncRNA MALAT1) acted as a tumor promoter to promote cell carcinogenesis in non-small cell lung cancer (NSCLC). MALAT1 was found to exist in serum exosomes of several cancers. However, the role of exosomal-derived MALAT1 in NSCLC remains poorly understood.

Materials and Methods

Exosomes were isolated using the ExoQuick precipitation kit. Western blot was used to detect the protein expression of CD3, CD63, apoptosis- and metastasis-related protein. The expression of MALAT1, microRNA (miR)-515-5p and eukaryotic elongation factor 2 (EEF2) mRNA was detected using quantitative real-time polymerase chain reaction. Cell viability, apoptosis, or invasion were measured using 3-(4, 5)-dimethylthiahiazo (-z-y1)-3, 5-di-phenytetrazoliumromide (MTT) assay, flow cytometry or transwell assay, respectively. The interaction between miR-515-5p and MALAT1 or EEF2 was confirmed by dual-luciferase reporter assay. In vivo experiments were conducted through the murine xenograft model.

Results

MALAT1 was highly expressed in serum and cell exosomes from NSCLC patients. MALAT1 knockdown repressed cell proliferation, invasion and induced cell apoptosis in vitro as well as inhibited tumor growth in vivo in NSCLC. Subsequently, we confirmed that MALAT1 was a sponge of miR-515-5p, and EEF2 was a target of miR-515-5p. Furthermore, MALAT1 served as a sponge of miR-515-5p to regulate EEF2 expression in NSCLC cells. More importantly, MALAT1 deletion  performed anti-tumor effects by interacting with miR-515-5p/EEF2 axis in vitro and in vivo in NSCLC.

Conclusion

MALAT1 knockdown repressed NSCLC tumorigenicity by inhibiting cell proliferation, invasion and promoting apoptosis through regulating miR-515-5p/EEF2, besides, MALAT1 was highly enriched in exosomes of NSCLC, suggesting a possible molecular-targeted therapy for NSCLC patients.

Identification, expression and functional analysis of prmt7 in medaka Oryzias latipes

Arginine methylation is an important posttranslational modification and catalyzed by a family of protein arginine methyltransferases (PRMTs). PRMT7 is the type III PRMT and produces solely monomethylarginine products. PRMT7 has been found to play important roles in multiple biological processes in mammals. However, the expression pattern and function of Prmt7 remain largely unknown in fish. In this study, we characterized the medaka prmt7 gene and determined its expression pattern and function during embryogenesis and germ cell development. The results showed that the chromosomal location and gene structure of medaka prmt7 were similar to its mammalian orthologs. Comparisons of deduced amino acid sequences indicated that medaka Prmt7 was a homolog of human PRMT7 with two methyltransferase domains. Reverse transcription-polymerase chain reaction (RT-PCR) and real time RT-PCR revealed that medaka prmt7 had maternal origin with continuous and dynamical expression during embryonic development. Whole-mount in situ hybridization analysis observed that the transcripts of prmt7 were ubiquitous at morula and gastrula stage, and were later riched in the brain and otic vesicles during embryogenesis. In the adult stage, prmt7 messenger RNA was detected in all examined tissues with the high levels in the ovary and testis. The expression of prmt7 in the gonads was restricted to oocytes of the ovary and spermatids/sperm of the testis. Functional analysis showed that knockdown of medaka prmt7 did not reduce the total number of primordial germ cells (PGCs) in vivo but significantly affected PGCs distribution during embryonic development. These results indicate that prmt7 may be involved in germ cell development in medaka.

PRMT7 promotes the growth of renal cell carcinoma through modulating the β-catenin/C-MYC axis

Arginine methylation is mainly catalyzed by protein arginine methyltransferases (PRMTs) and is one of the most common posttranslational modifications closely related to the development of cancer. PRMT7 is overexpressed in various tumors and promotes the malignant progression of tumors, but the expression and role of PRMT7 in renal cell carcinoma (RCC) remains unclear. Here, we report for the first time that the expression of PRMT7 is increased in clear cell renal cell carcinoma (ccRCC) tissues and that it may act as an independent predictor for the poor prognosis of ccRCC patients. We found that PRMT7 promotes RCC cell proliferation both in vitro and in vivo. Moreover, the methyltransferase inhibitor adenosine dialdehyde (Adox) blocks the action of PRMT7 in ccRCC cells. Furthermore, PRMT7 regulates the expression of C-MYC, which plays an important role in promoting ccRCC cell proliferation, and it accelerates the tumor development of RCC in a C-MYC-dependent manner. Mechanistically, PRMT7 upregulates the expression of C-MYC via methylating β-catenin and inhibiting the ubiquitin-mediated degradation of β-catenin. In conclusion, our study demonstrates that overexpressed PRMT7 in ccRCC cells acts as an oncogene to promote the growth of renal cell carcinoma through regulating the β-catenin/C-MYC axis, thereby providing new strategies and targets for the treatment of ccRCC patients.

Targeting epigenetic regulators for cancer therapy: mechanisms and advances in clinical trials

Epigenetic alternations concern heritable yet reversible changes in histone or DNA modifications that regulate gene activity beyond the underlying sequence. Epigenetic dysregulation is often linked to human disease, notably cancer. With the development of various drugs targeting epigenetic regulators, epigenetic-targeted therapy has been applied in the treatment of hematological malignancies and has exhibited viable therapeutic potential for solid tumors in preclinical and clinical trials. In this review, we summarize the aberrant functions of enzymes in DNA methylation, histone acetylation and histone methylation during tumor progression and highlight the development of inhibitors of or drugs targeted at epigenetic enzymes.

Chemical probes for protein arginine methyltransferases

Protein arginine methyltransferases (PRMTs) catalyze the transfer of methyl groups to specific arginine residues of their substrates using S-adenosylmethionine as a methyl donor, contributing to regulation of many biological processes including transcription, and DNA damage repair. Dysregulation of PRMT expression is often associated with various diseases including cancers. Different methods have been used to characterize the activities of PRMTs and determine their kinetic parameters including mass spectrometry, radiometric, and antibody-based assays. Here, we present kinetic characterization of PRMTs using a radioactivity-based assay for better comparison along with previously reported values. We also report on full characterization of PRMT9 activity with SAP145 peptide as substrate. We further review the potent, selective and cell-active PRMT inhibitors discovered in recent years to provide a better understanding of available tools to investigate the roles these proteins play in health and disease.

Zebrafish prmt7 negatively regulates antiviral responses by suppressing the retinoic acid-inducible gene-I-like receptor signaling

Arginine methylation is a post-translational modification in histone and nonhistone proteins that can affect numerous cellular activities. Protein arginine methyltransferase 7 (Prmt7), a type III arginine methyltransferase, catalyzes the formation of stable monomethylarginines of histones. The role of PRMT7 in virus-induced innate immunity signaling, however, remains largely unknown. We demonstrate that zebrafish prmt7 could be inhibited by spring viremia of carp virus (SVCV) and grass carp reovirus (GCRV) infection. The overexpression of prmt7 suppresses cellular antiviral responses that are partially dependent on the arginine methyltransferase activity of prmt7. Consistently, prmt7-null zebrafish were more resistant to SVCV or GCRV infection, exhibiting enhanced expression of key antiviral genes and fewer necrotic cells in the liver and kidney upon viral infection. Furthermore, we established a zebrafish model to investigate grass carp hemorrhagic disease. Our findings suggest that by suppressing the RIG-I-like receptors signaling, zebrafish prmt7 negatively regulates antiviral responses, indicating the vital role of prmt7 and its arginine methyltransferase activity in innate immunity.