PRMT3-mediated arginine methylation of IGF2BP1 promotes oxaliplatin resistance in liver cancer

NEIL3 Deficiency Enhances HCC Cell Sensitivity to Oxaliplatin by Inhibiting the Fanconi Anaemia Pathway

Despite some achievements in oxaliplatin-based chemotherapy for the treatment of advanced hepatocellular carcinoma (HCC), the abnormal activation of DNA damage repair pathways in HCC cells remains a major problem, limiting the efficacy of oxaliplatin-based chemotherapy. In a previous study, we found that endonuclease VIII-like protein 3 (NEIL3) is expressed in a high proportion of patients with HCC and associated with an unfavourable prognosis. However, the role of NEIL3 in chemoresistance is still unclear. The aim of this study was to evaluate whether and how NEIL3 regulates oxaliplatin anti-tumour efficacy. Gene expression after oxaliplatin treatment in HCC cell lines was assessed by real-time quantitative PCR, western blot analysis and bioinformatics analysis. The effect of NEIL3 on regulating oxaliplatin efficacy was assessed using cell counting kit-8 assays, colony formation assays, flow cytometry and an in vivo nude mice study. Mechanistic insights into the sensitivity to oxaliplatin mediated by the inhibition of NEIL3 were obtained through immunofluorescence and RNA sequencing analyses. Our findings demonstrated that NEIL3 expression was markedly downregulated after oxaliplatin administration. NEIL3 knockdown impaired cell viability and colony formation and increased apoptosis in HCC cells exposed to oxaliplatin. In addition, NEIL3 inhibition reduced tumour progression and enhanced oxaliplatin efficacy in xenograft nude mice models. Furthermore, knocking down NEIL3 significantly increased the oxaliplatin-mediated inhibition of the Fanconi anaemia pathway. Our results revealed that NEIL3 may be a promising therapeutic target for improving oxaliplatin efficacy in the treatment of HCC.

[High expression of DTX2 promotes proliferation, invasion and epithelial-mesenchymal transition of oxaliplatin-resistant colorectal cancer cells]

OBJECTIVES

To investigate the role of DTX2 in regulating biological behaviors of oxaliplatin-resistant colorectal cancer cells (CRC/OXA cells).

METHODS

CCK8 assay was used to determine the inhibition rate of oxaliplatin-treated CRC cells. A CRC/OXA cell line was constructed, in which DTX2 expression level was detected. The cells were transfected with a DTX2-shRNA plasmid or co-transfected with DTX2-shRNA and pcDNA-Notch2, and the changes in cell proliferation, migration and invasion ability were evaluated using plate cloning assay, scratch assay and Transwell invasion assay. The expression levels of Notch2, NICD and epithelial-mesenchymal transition (EMT) proteins of the transfected cells were detected with Western blotting. In a nude mouse model bearing SW620/OXA cell xenografts, the effects of DTX2 knockdown and Notch2 overexpression in the implanted cells on tumor growth and protein expressions were tested.

RESULTS

The IC50 of oxaliplatin was 6.00 μmol/L in SW620 cells and 8.00 μmol/L in LoVo cells. CRC/OXA cells showed a significantly increased expression of DTX2. DTX2 knockdown in CRC/OXA cells significantly inhibited cell proliferation, migration and invasion, and these effects were reversed by co-transfection of the cells with pcDNA-Notch2. DTX2 knockdown significantly reduced the expression levels of Notch2, NICD and vimentin proteins and increased E-cadherin expression in CRC/OXA cells, and co-transfection with pcDNA-Notch2 potently attenuated the changes in these proteins. In the tumor-bearing mice, DTX2 overexpression obviously promoted the growth of SW620/OXA cell xenograft, enhanced the protein expressions of Notch2, NICD and vimentin, and lowered the expression of E-cadherin.

CONCLUSIONS

High expression of DTX2 promotes proliferation, migration, invasion and EMT of CRC/OXA cells through the Notch2 signaling pathway, suggesting the potential of DTX2 as a target to improve the efficacy of oxaliplatin.

PDZK1 inhibits MRP2-mediated oxaliplatin chemosensitivity in hepatocellular carcinoma

Recurrence after oxaliplatin chemotherapy is a major challenge in the treatment of advanced hepatocellular carcinoma patients. Differential expression gene analysis and Kaplan-Meier curves were screened biomarkers associated with OXA-treated recurrence in GSE51951, TCGA-LIHC, and Chinese Liver Cancer Atlas databases. We retrospectively collected 39 cases of HCC treated with platinum based drugs at the First Hospital of Shanxi Medical University. Immunohistochemistry was used to analyze the relationship between PDZK1 expression and patient recurrence of HCC. Cell model and subcutaneous transplant tumor model of HCC were established to detect the cell growth ability treated with OXA. Gene Set Enrichment Analysis analysis identified signaling pathways associated with high PDZK1. Co-Immunoprecipitation and immunofluorescence experiments were used to explore the potential interaction between PDZK1 and MRP2. We identified that high expression of PDZK1 was associated with OXA resistance and poor prognosis in HCC. PDZK1 promoted the cell viability, migration, and invasion of HCC after OXA treatment in vitro and vivo. MRP2-mediated ABC transporters pathway and bile acid metabolism were significantly activated in the PDZK1 overexpression group of HCC. PDZK1 interacted and co-localized with the carboxyl terminal PDZ binding motif of MRP2. Clinical specimen analysis have shown a positive correlation between the protein levels of PDZK1 and MRP2. Our study identified PDZK1 as a novel biomarker significantly associated with OXA chemosensitivity in HCC. Mechanistically, PDZK1 promoted the OXA sensitivity of HCC by activating the MRP2-mediated signaling pathway.

Histone lactylation drives liver cancer metastasis by facilitating NSF1-mediated ferroptosis resistance after microwave ablation

Insufficient microwave ablation (IMWA) is linked to aggressive hepatocellular carcinoma (HCC) progression. An increase in lactate levels after sublethal heat stress (HS) has been confirmed in HCC. However, the role of lactate-related histone lactylation in the progression of HCC caused by sublethal HS remains unclear. Here, we found that the metastatic potential of HCC increased in a lactate-dependent manner after IMWA. Moreover, sublethal HS triggered an increase in H3K18la modification, as validated in a cell-derived xenograft mouse model and human HCC samples. By performing an integrated analysis of proteomic and transcriptomic profiles, we revealed that HCC cells exhibited increased intracellular iron ion homeostasis and developed resistance to platinum-based drugs after exposure to sublethal HS. We subsequently integrated proteomic and transcriptomic data with H3K18la-specific chromatin immunoprecipitation (ChIP) sequencing to identify candidate genes involved in sublethal heat treatment-induced HCC cell metastasis. Mechanically, an increase in H3K18la modification enhanced the transcriptional activity of NFS1 cysteine desulfurase (NFS1), a key player in iron‒sulfur cluster biosynthesis, thereby reducing the susceptibility of HCC to ferroptosis after IMWA. Knocking down NFS1 diminished the metastatic potential of sublethally heat-treated HCC cells. Additionally, NFS1 deficiency exhibited a synergistic effect with oxaliplatin, leading to the significant inhibition of the metastatic capability of HCC cells both in vitro and in vivo, regardless of sublethal HS treatment. In conclusion, our study revealed the oncogenic role of histone lactylation in HCC after IMVA. We also bridged histone lactylation with ferroptosis, providing novel therapeutic targets for HCC following microwave ablation, particularly when combined with oxaliplatin-based chemotherapy.

Increased keratin 80 expression predicts poor prognosis and promotes oxaliplatin resistance in gastric cancer

BACKGROUND

Keratin 80 (KRT80), a type I intermediate filament protein, is a member of the keratin family with specialized functions in epithelial tissues. While KRT80 has been implicated in both normal physiological processes and various diseases, its role in gastric cancer (GC), particularly its expression and prognostic significance, remains poorly understood. In this study, we investigated the role and underlying molecular mechanisms of KRT80 in oxaliplatin resistance in GC. Our analysis revealed that KRT80 is significantly upregulated in GC tissues and is associated with poor clinical prognosis. The role of KRT80 in GC cell proliferation was assessed through in vitro and in vivo assays.

AIM

To explore the expression of KRT80 in GC and its impact on the prognosis of patients.

METHODS

KRT80 expression in GC tissues was analyzed using Western blotting, quantitative reverse transcription PCR, multiple immunofluorescence staining, and immunohistochemistry. Survival analysis was conducted using the Kaplan-Meier method with the log-rank test. The role of KRT80 in GC cell proliferation was assessed through in vitro and in vivo assays. Immunoprecipitation and mass spectrometry analyses identified elongation factor 1-alpha 1 (EEF1A1) as a binding protein of KRT80.

RESULTS

Integrating our experimental findings with multiple published studies, we found that increased KRT80 expression is associated with poor prognosis in GC and promotes resistance to oxaliplatin. Moreover, we have preliminarily verified the interaction between KRT80 and EEF1A1. Therefore, this study provides a novel perspective on overcoming oxaliplatin resistance in GC.

CONCLUSION

Increased KRT80 expression predicts poor prognosis and promotes oxaliplatin resistance in GC, suggesting its potential as a novel prognostic biomarker.

KLX ameliorates liver cancer progression by mediating ZBP1 transcription and ubiquitination and increasing ZBP1-induced PANoptosis

Liver cancer is a highly aggressive malignancy with poor survival rates. Current treatments, including liver transplantation, immunotherapy, and gene therapy, are often limited by late-stage diagnosis and significant side effects, highlighting the urgent need for novel therapeutic agents. In this study, we evaluated the therapeutic potential of Kanglexin (KLX), a novel anthraquinone derivative, in the treatment of liver cancer. In vitro, KLX inhibited the proliferation and migration of HepG2 and Hep3B cells in a dose-dependent manner. Mechanistically, KLX upregulated Z-DNA binding protein 1 (ZBP1) expression, inducing PANoptosis by directly binding to ZBP1, altering its conformation, and reducing its affinity for the E3 ubiquitin ligase ring finger protein 180 (RNF180). This interaction decreased ZBP1 ubiquitination, thereby increasing its stability. Additionally, KLX upregulated the expression of the transcription factor homeobox D10 (HOXD10), which further increased ZBP1 expression. Elevated ZBP1 levels significantly suppressed liver cancer cell proliferation and migration, whereas the inhibitory effects of KLX were reversed upon ZBP1 knockdown. In a xenograft model, KLX significantly inhibited tumor growth with a lower toxicity than oxaliplatin (OXA). In conclusion, KLX promoted PANoptosis in liver cancer cells by upregulating ZBP1 and preventing its degradation, thereby inhibiting liver cancer progression and migration. These findings suggest that KLX is a promising therapeutic agent for liver cancer.

Doxorubicin prodrug for γ-glutamyl transpeptidase imaging and on-demand cancer therapy

The γ-glutamyl transpeptidase (γ-GGT) is an important tumor marker, which has been reported to be firmly associated with the developmental stage of liver cancer. Therefore, it makes sense to image and monitor γ-GGT level and design γ-GGT-responsive prodrug for integrated diagnosis and treatment of liver cancer. Herein, we prepare a doxorubicin (Dox) prodrug for imaging γ-GGT and on-demand treating liver cancer. When γ-GGT exists, the γ-glutamyl group will be cut off to liberate free Dox for monitoring cancer progression and killing tumor cells. Fortunately, little Dox is released due to the low level of γ-GGT in normal cells, which improves the safety and efficiency of chemotherapy. To further improve the tumor targeted ability, Dox prodrug is loaded in hyaluronic acid modified liposome nanoparticles to form the nano-prodrug. Then nano-prodrug is enriched in the tumor by binding to the high expressed CD44 on cancer cells. With the assistance of anti-PD-L1, nano-prodrug effectively inhibits the growth of proximal and distal tumors.

Emerging importance of m6A modification in liver cancer and its potential therapeutic role

Liver cancer refers to malignant tumors that form in the liver and is usually divided into several types, the most common of which is hepatocellular carcinoma (HCC), which originates in liver cells. Other rare types of liver cancer include intrahepatic cholangiocarcinoma (iCCA). m6A modification is a chemical modification of RNA that usually manifests as the addition of a methyl group to adenine in the RNA molecule to form N6-methyladenosine. This modification exerts a critical role in various biological processes by regulating the metabolism of RNA, affecting gene expression. Recent studies have shown that m6A modification is closely related to the occurrence and development of liver cancer, and m6A regulators can further participate in the pathogenesis of liver cancer by regulating the expression of key genes and the function of specific cells. In this review, we provided an overview of the latest advances in m6A modification in liver cancer research and explored in detail the specific functions of different m6A regulators. Meanwhile, we deeply analyzed the mechanisms and roles of m6A modification in liver cancer, aiming to provide novel insights and references for the search for potential therapeutic targets. Finally, we discussed the prospects and challenges of targeting m6A regulators in liver cancer therapy.

PRMT3 drives PD-L1-mediated immune escape through activating PDHK1-regulated glycolysis in hepatocellular carcinoma

Aberrant expression of programmed death ligand-1 (PD-L1) facilitates tumor immune evasion. Protein arginine methyltransferase 3 (PRMT3), a member of type I PRMT family, mediates asymmetric dimethylarginine (ADMA) modification of various substrate proteins. This study investigates the role of PRMT3 in PD-L1-associated tumor immunosuppression in hepatocellular carcinoma (HCC). Hepatocyte-specific knockout of Prmt3 significantly suppressed HCC progression in DEN-CCL4-treated mice. Knockout of Prmt3 in HCC cells markedly increased CD8+ T cell infiltration, and reduced lactate production in tumors. PRMT3 interacted with pyruvate dehydrogenase kinase 1 (PDHK1), asymmetric dimethylation of PDHK1 at arginine 363 and 368 residues and increased its kinase activity. The R363/368 K mutant or inhibition of PDHK1 by JX06 blocked the effect of PRMT3 on lactate production. JX06 treatment also attenuated the tumor-promoting role of PRMT3 in HCC in vitro and in vivo. Furthermore, RNA-seq analysis revealed that knockout of PRMT3 downregulates the tumor-associated immune checkpoint, PD-L1, in tumor tissues. Chromatin immunoprecipitation (ChIP) assay demonstrated that PRMT3 promotes lactate-induced PD-L1 expression by enhancing the direct binding of histone H3 lysine 18 lactylation (H3K18la) to the PD-L1 promoter. Tissue microarray analysis showed a positive correlation between PRMT3 and PD-L1 expression in HCC patients. Anti-PD-L1 treatment reversed PRMT3-induced tumor growth and restored CD8+ T cell infiltration. Our research links PRMT3-mediated metabolic reprogramming and immune evasion, revealing that the PRMT3-PDHK1-lactate-PD-L1 axis may be a potential target for improving the efficacy of immunotherapy in HCC.

PADI4 facilitates stem-like properties and cisplatin resistance through upregulating PRMT2/IDs family in oesophageal squamous cell carcinoma

BACKGROUND

Oesophageal squamous cell carcinoma (OSCC) is a highly lethal cancer characterized by its aggressive nature and chemotherapy resistance. Peptidylarginine deiminase 4 (PADI4) regulates protein citrullination and is associated with various cancer developments. The role of PADI4 in OSCC progression and chemoresistance remains unexplored.

METHODS

The protein interactions were conducted by immunoprecipitation assays. Quantitative real-time PCR and western blotting were utilized to quantifyexpression levels in cancer cells. The stem-like properties were assessed through spheroid growth assays and Cancer Stem Cells (CSCs) markers. Additionally, the resistance of cancer cells to cisplatin was evaluated using CCK8 assay.

RESULTS

This study shows that PADI4 promotes cellular stemness, contributing to the progression and chemoresistance of OSCC. Mechanistically, PADI4 facilitates the citrullination of protein arginine methyltransferase 2 (PRMT2), a process essential for the stabilization of PRMT2 expression and the enhancement of its function in promoting the transcription of IDs family (ID1 and ID2) via histone arginine methylation. This mechanism subsequently increases tumour stemness and contributes to the cisplatin resistance observed in OSCC. Mutations at the R312 site or inhibition by GSK484 can attenuate tumour stemness in OSCC, thereby reducing cisplatin resistance.

CONCLUSION

PADI4 promotes citrullination and stabilization of PRMT2, enhancing its function in upregulating ID1 and ID2 expression via histone arginine methylation, which increases stemness and contributes to cisplatin resistance in OSCC; this effect can be mitigated by R312 mutations or GSK484 inhibition, reducing stemness and cisplatin resistance.

KEY POINTS

The role of citrullinization in cisplatin resistance of OSCC. PADI4 citrullinate of PRMT2 and stabilize PRMT2. PADI4 citrullinate of PRMT2 promoting the transcription of IDs family (ID1, ID2 and ID3) via histone arginine methylation. PADI4 citrullinated PRMT2 affected the combination of PRMT2 and USP7. PADI4 citrullinate of PRMT2 at R312 site. PADI4 inhibitor GSK484 can affect the stemness of OSCC and cisplatin resistance.

METTL3 confers oxaliplatin resistance through the activation of G6PD-enhanced pentose phosphate pathway in hepatocellular carcinoma

Oxaliplatin-based therapeutics is a widely used treatment approach for hepatocellular carcinoma (HCC) patients; however, drug resistance poses a significant clinical challenge. Epigenetic modifications have been implicated in the development of drug resistance. In our study, employing siRNA library screening, we identified that silencing the m6A writer METTL3 significantly enhanced the sensitivity to oxaliplatin in both in vivo and in vitro HCC models. Further investigations through combined RNA-seq and non-targeted metabolomics analysis revealed that silencing METTL3 impeded the pentose phosphate pathway (PPP), leading to a reduction in NADPH and nucleotide precursors. This disruption induced DNA damage, decreased DNA synthesis, and ultimately resulted in cell cycle arrest. Mechanistically, METTL3 was found to modify E3 ligase TRIM21 near the 3'UTR with N6-methyladenosine, leading to reduced RNA stability upon recognition by YTHDF2. TRIM21, in turn, facilitated the degradation of the rate-limiting enzyme of PPP, G6PD, through the ubiquitination-proteasome pathway. Importantly, high expression of METTL3 was significantly associated with adverse prognosis and oxaliplatin resistance in HCC patients. Notably, treatment with the specific METTL3 inhibitor, STM2457, significantly improved the efficacy of oxaliplatin. These findings underscore the critical role of the METTL3/TRIM21/G6PD axis in driving oxaliplatin resistance and present a promising strategy to overcome chemoresistance in HCC.

Targeting Wnt signaling in cancer drug resistance: Insights from pre-clinical and clinical research

Cancer drug resistance, encompassing both acquired and intrinsic chemoresistance, remains a significant challenge in the clinical management of tumors. While advancements in drug discovery and the development of various small molecules and anti-cancer compounds have improved patient responses to chemotherapy, the frequent and prolonged use of these drugs continues to pose a high risk of developing chemoresistance. Therefore, understanding the primary mechanisms underlying drug resistance is crucial. Wnt proteins, as secreted signaling molecules, play a pivotal role in transmitting signals from the cell surface to the nucleus. Aberrant expression of Wnt proteins has been observed in a variety of solid and hematological tumors, where they contribute to key processes such as proliferation, metastasis, stemness, and immune evasion, often acting in an oncogenic manner. Notably, the role of the Wnt signaling pathway in modulating chemotherapy response in human cancers has garnered significant attention. This review focuses on the involvement of Wnt signaling and its related molecular pathways in drug resistance, highlighting their associations with cancer hallmarks, stemness, and tumorigenesis linked to chemoresistance. Additionally, the overexpression of Wnt proteins has been shown to accelerate cancer drug resistance, with regulation mediated by non-coding RNAs. Elevated Wnt activity reduces cell death in cancers, particularly by affecting mechanisms like apoptosis, autophagy, and ferroptosis. Furthermore, pharmacological compounds and small molecules have demonstrated the potential to modulate Wnt signaling in cancer therapy. Given its impact, Wnt expression can also serve as a prognostic marker and a factor influencing survival outcomes in human cancers.

Development of Cytolytic Iridium-Complexed Octaarginine Peptide Albumin Nanomedicine for Hepatocellular Carcinoma Treatment

Objective

Hepatocellular carcinoma is one of the most challenging malignancies and has high incidence and mortality rates worldwide. Digital subtraction angiography (DSA)-guided hepatic arterial infusion of the standard chemotherapeutic agent oxaliplatin (OXA) has the advantages of both precision and efficacy, making it an important therapeutic strategy for advanced-stage liver cancer. However, patients receiving this treatment still face severe systemic toxicity and poor tolerability of oxaliplatin.

Methods

In this study, we compared oxaliplatin with novel albumin-formulated oncolytic peptide nanoparticles, Ir-cR8 (abbreviated as iPep), in the treatment of orthotopic liver cancer in a mouse model by intravenous injection and in a rabbit model via DSA-guided hepatic arterial infusion.

Results

The results showed that intravenous Ir-cR8-BSA-NPs had enhanced inhibitory effects to the growth of H22 ectopic liver tumors in mice and also with reduced toxicity in animals compared to OXA treatment. Specifically, Ir-cR8-BSA-NPs-treated mice showed approximately 92% tumor growth inhibition compared to approximately 88% for OXA. In the rabbit VX2 ectopic hepatocellular carcinoma model, Ir-cR8-BSA-NPs demonstrated significantly stronger inhibition (P<0.01) of tumor size compared to OXA, as assessed by PET/CT imaging, with SUV values decreasing from 5.15±0.46 to 2.52±0.57, compared to OXA-treated group, which decreased from 5.44±0.43 to 3.90±0.24. Furthermore, Ir-cR8- BSA-NPs significantly improved stability by albumin encapsulation and reduced hemolytic toxicity (P<0.001), resulting in improved therapeutic efficacy.

Conclusion

This study demonstrated the combined advantages of a novel membrane-active oncolytic peptide nanomedicine and precise drug delivery enabled by arterial infusion technology for the interventional treatment of liver cancer.

Ursolic acid in colorectal cancer: mechanisms, current status, challenges, and future research directions

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally, contributing to approximately 10% of all cancer cases and representing the second leading cause of cancer-related mortality worldwide. Ursolic acid (UA), a widely studied pentacyclic triterpenoid, has attracted substantial attention from researchers and clinicians due to its potential therapeutic effects against malignant tumors. Multiple studies have confirmed that UA inhibits tumor cell proliferation, induces differentiation and apoptosis, suppresses invasion, and impedes tumor angiogenesis via diverse mechanisms. However, research specifically addressing UA's anti-CRC effects remains limited, and systematic reviews of its underlying mechanisms in CRC are scarce. This study seeks to provide a comprehensive review of UA's mechanisms of action against CRC, offering valuable insights and references for researchers and clinicians.

PRMT3 and CARM1: Emerging Epigenetic Targets in Cancer

The family of protein arginine methyltransferases (PRMTs) occupies an important position in biology, especially during the initiation and development of cancer. PRMT3 and CARM1(also known as PRMT4), being type I protein arginine methyltransferases, are key in controlling tumour progression by catalysing the mono-methylation and asymmetric di-methylation of both histone and non-histone substrates. This paper reviews the functions and potential therapeutic target value of PRMT3 and CARM1 in a variety of cancers. Studies have identified abnormal expressions of PRMT3 and CARM1 in several malignancies, closely linked to cancer progression, advancement, and resistance to treatment. Such as hepatocellular carcinoma, colorectal cancer, ovarian cancer, and endometrial cancer. These findings offer new strategies and directions for cancer treatment, especially in enhancing the effectiveness of conventional treatment methods.

Citrullinated IGF2BP1 promotes rheumatoid synovial aggression via increasing the mRNA stability of SEMA3D

Protein citrullination modification plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA), and anti-citrullinated protein antibodies (ACPAs) are extensively employed for clinical diagnosis of RA. However, there remains limited understanding regarding specific citrullinated proteins and their implications in the progression of RA. In this study, we screen and verify insulin-like growth factor-2 mRNA binding protein 1 (IGF2BP1) as a novel citrullinated protein with significantly elevated citrullinated level in RA. Autoantibodies against citrullinated IGF2BP1 are further detected in serum and synovial fluid samples from RA patients, which are positively correlated with erythrocyte sedimentation rate (ESR) and disease activity score 28 (DAS28). Transcriptomic sequencing and functional verification show that citrullination at the R167 site of IGF2BP1 promotes the proliferation, migration, and invasion of RA fibroblast-like synoviocytes (RA-FLSs) by improving the mRNA stability of Semaphorin 3D (SEMA3D). Experiments in collagen-induced arthritis (CIA) mice, the classical animal model of RA, show that IGF2BP1 R176K point mutation (Igf2bp1R167K/R167K) mice exert reduced inflammatory response, clinical scores, and joint destruction. At a molecular level, citrullination of IGF2BP1 promotes the stability of SEMA3D mRNA by promoting the interaction between IGF2BP1 and its cofactor ELAV-like protein 1 (ELAVL1), thereby promoting the invasiveness of RA-FLSs. In this study, a new citrullinated protein of IGF2BP1 is discovered, and the molecular mechanism of its citrullinated modification promoting the progression of RA disease is elucidated, which provides theoretical basis for the diagnosis and treatment of RA.

STAMBPL1/TRIM21 Balances AXL Stability Impacting Mesenchymal Phenotype and Immune Response in KIRC

Kidney renal clear cell carcinoma (KIRC) is recognized as an immunogenic tumor, and immunotherapy is incorporated into its treatment landscape for decades. The acquisition of a tumor mesenchymal phenotype through epithelial-to-mesenchymal transition (EMT) is associated with immune evasion and can contribute to immunotherapy resistance. Here, the involvement of STAM Binding Protein Like 1 (STAMBPL1) is reported in the development of mesenchymal and immune evasion phenotypes in KIRC cells. Mechanistically, STAMBPL1 elevated protein abundance and surface accumulation of TAM Receptor AXL through diminishing the TRIM21-mediated K63-linked ubiquitination and subsequent lysosomal degradation of AXL, thereby enhancing the expression of mesenchymal genes while suppressing chemokines CXCL9/10 and HLA/B/C. In addition, STAMBPL1 enhanced PD-L1 transcription via facilitating nuclear translocation of p65, and knockdown (KD) of STAMBPL1 augmented antitumor effects of PD-1 blockade. Furthermore, STAMBPL1 silencing and the tyrosine kinase inhibitor (TKI) sunitinib also exhibited a synergistic effect on the suppression of KIRC. Collectively, targeting the STAMBPL1/TRIM21/AXL axis can decrease mesenchymal phenotype and potentiate anti-tumor efficacy of cancer therapy.

Novel insights into the interaction between IGF2BPs and ncRNAs in cancers

Insulin-like growth factor II mRNA-binding proteins (IGF2BPs), a family of RNA-binding proteins, are pivotal in regulating RNA dynamics, encompassing processes such as localization, metabolism, stability, and translation through the formation of ribonucleoprotein complexes. First identified in 1999 for their affinity to insulin-like growth factor II mRNA, IGF2BPs have been implicated in promoting tumor malignancy behaviors, including proliferation, metastasis, and the maintenance of stemness, which are associated with unfavorable outcomes in various cancers. Additionally, non-coding RNAs (ncRNAs), particularly long non-coding RNAs, circular RNAs, and microRNAs, play critical roles in cancer progression through intricate protein-RNA interactions. Recent studies, predominantly from 2018 onward, indicate that IGF2BPs can recognize and modulate ncRNAs via N6-methyladenosine (m6A) modifications, enriching the regulatory landscape of RNA-protein interactions in the context of cancer. This review explores the latest insights into the interplay between IGF2BPs and ncRNAs, emphasizing their potential influence on cancer biology.

N6-methyladenosine-modified long non-coding RNA KIF9-AS1 promotes stemness and sorafenib resistance in hepatocellular carcinoma by upregulating SHOX2 expression

BACKGROUND

Hepatocellular carcinoma (HCC) is a prevalent and aggressive tumor. Sorafenib is the first-line treatment for patients with advanced HCC, but resistance to sorafenib has become a significant challenge in this therapy. Cancer stem cells play a crucial role in sorafenib resistance in HCC. Our previous study revealed that the long non-coding RNA (lncRNA) KIF9-AS1 is an oncogenic gene in HCC. However, the role of KIF9-AS1 in drug resistance and cancer stemness in HCC remains unclear. Herein, we aimed to investigate the function and mechanism of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC.

AIM

To describe the role of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC and elucidate the underlying mechanism.

METHODS

Tumor tissue and adjacent non-cancerous tissue samples were collected from HCC patients. Sphere formation was quantified via a tumor sphere assay. Cell viability, proliferation, and apoptosis were evaluated via Cell Counting Kit-8, flow cytometry, and colony formation assays, respectively. The interactions between the lncRNA KIF9-AS1 and its downstream targets were confirmed via RNA immunoprecipitation and coimmunoprecipitation. The tumorigenic role of KIF9-AS1 was validated in a mouse model.

RESULTS

Compared with that in normal controls, the expression of the lncRNA KIF9-AS1 was upregulated in HCC tissues. Knockdown of KIF9-AS1 inhibited stemness and attenuated sorafenib resistance in HCC cells. Mechanistically, N6-methyladenosine modification mediated by methyltransferase-like 3/insulin-like growth factor 2 mRNA-binding protein 1 stabilized and increased the expression of KIF9-AS1. Additionally, KIF9-AS1 increased the stability and expression of short stature homeobox 2 by promoting ubiquitin-specific peptidase 1-induced deubiquitination. Furthermore, depletion of KIF9-AS1 alleviated sorafenib resistance in a xenograft mouse model of HCC.

CONCLUSION

The N6-methyladenosine-modified lncRNA KIF9-AS1 promoted stemness and sorafenib resistance in HCC by upregulating short stature homeobox 2 expression.

GSDMB interacts with IGF2BP1 to suppress colorectal cancer progression by modulating DUSP6-ERK pathway

There is growing evidence that the protein family of Gasdermins (GSDMs) play an essential role during the progression of colorectal cancer (CRC). However, it is not completely clear that how GSDMB, abundantly expressed in epithelial cells of gastrointestinal tract, regulates the tumorigenesis of CRC. A wealth of evidence linking GSDMB to the pathogenesis of cancer has come from genome-wide association studies. Here, we provide evidence that aberrantly upregulated GSDMB is responsible for suppressing the CRC progression by using in vitro cell and intestinal organoid, as well as in vivo GSDMB transgenic mice models. Mechanistically, GSDMB interacts with insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), which directly binds to and recognizes the 3'-UTR of dual specificity phosphatase 6 (DUSP6) mRNA, enhances the translation of DUSP6 protein and inhibits downstream ERK phosphorylation, thereby facilitating cell death and restraining cell proliferation. Our results suggest that GSDMB has potential as a novel therapeutic target for CRC treatment.

Therapeutic targeting potential of the protein lysine and arginine methyltransferases to reverse cancer chemoresistance

Cancer treatments have continued to improve tremendously over the past decade, but therapy resistance is still a common, major factor encountered by patients diagnosed with cancer. Chemoresistance arises due to various circumstances and among these causes, increasing evidence has shown that enzymes referred to as protein methyltransferases (PMTs) play a significant role in the development of chemoresistance in various cancers. These enzymes are responsible for the methylation of different amino acids, particularly lysine and arginine, via protein lysine methyltransferases (PKMTs) and protein arginine methyltransferases (PRMTs), respectively. Various PMTs have been identified to be dysregulated in the development of cancer and chemoresistance. Nonetheless, the functional role of these PMTs in the development of chemoresistance is poorly characterised. This advocates the need for innovative approaches and technologies suitable for better characterisation of these PMTs and their potential clinical inhibitors. In the case of a handful of PMTs, inhibitory small molecules which can function as anticancer drugs have been developed and have also entered clinical trials. Considering all this, PMTs have become a promising and valuable target in cancer chemoresistance related research. This review will give a small introduction on the different PKMTs and PRMTs families which are dysregulated in different cancers and the known proteins targeted by the respective enzymes. The focus will then shift towards PMTs known to be involved in chemoresistance development and the inhibitors developed against these, together with their mode of action. Lastly, the current obstacles and future perspectives of PMT inhibitors in cancer chemoresistance will be discussed.

The uncharacterized protein ZNF200 interacts with PRMT3 and aids its stability and nuclear translocation

Protein arginine methyltransferase 3 (PRMT3), a type I arginine methyltransferase is localized predominantly in the cytoplasm and regulates different cellular functions. Nevertheless, PRMT3 also exhibits regulatory functions in the nucleus by interacting with the liver X receptor alpha (LXRα) and catalyzes asymmetric dimethylation modifications at arginine 3 of histone 4 (H4R3me2a). However, very little is known about the regulation of the versatile global regulator PRMT3 and how PRMT3 is translocated to the nucleus. In this study, we identified ZNF200, a hitherto uncharacterized protein, as a potential binding partner of PRMT3 through yeast two-hybrid screening. We confirmed the interaction of PRMT3 with ZNF200 using immunoprecipitation and in vitro pull-down experiments. GST pull-down experiments and molecular docking studies revealed that the N-terminal zinc finger domain of PRMT3 binds to the C-terminal zinc finger regions of ZNF200. Furthermore, the evolutionary conservation of the Znf domain of PRMT3 correlates with the emergence of ZNF200 in mammals. We found that ZNF200 stabilizes PRMT3 by inhibiting its proteasomal degradation. ZNF200, a nuclear-predominant protein, promotes the nuclear translocation of PRMT3, leading to the global increase of H4R3me2a modifications. These findings imply that ZNF200 is a critical regulator of the steady-state levels and nuclear and epigenetic functions of PRMT3.

PCK1 as a target for cancer therapy: from metabolic reprogramming to immune microenvironment remodeling

Recently, changes in metabolites and metabolism-related enzymes related to tumor cell proliferation, metastasis, drug resistance, and immunosuppression have become a research hotspot, and researchers have attempted to determine the clinical correlation between specific molecular lesions and metabolic phenotypes. Convincing evidence shows that metabolic reprogramming is closely related to the proliferation, invasion, metastasis, and poor prognosis of malignant tumors. Therefore, targeting metabolic reprogramming is a new direction for cancer treatment. However, how molecular alterations in tumors contribute to metabolic diversity and unique targeting dependencies remains unclear. A full understanding of the underlying mechanisms of metabolic reprogramming in cancer may lead to better identification of therapeutic targets and the development of therapeutic strategies. Evidence for the importance of PCK1, a phosphoenolpyruvate carboxykinase 1, in tumorigenesis and development is accumulating. PCK1 can regulate cell proliferation and metastasis by remodeling cell metabolism. Additionally, PCK1 has "nonclassical" nonmetabolic functions, involving the regulation of gene expression, angiogenesis, epigenetic modification, and other processes, and has an impact on cell survival, apoptosis, and other biological activities, as well as the remodeling of the tumor immune microenvironment. Herein, we provide a comprehensive overview of the functions of PCK1 under physiological and pathological conditions and suggest that PCK1 is a potential target for cancer therapy. We also propose a future exploration direction for targeting PCK1 for cancer therapy from a clinical perspective. Finally, in view of the collective data, the results of our discussion suggest the potential clinical application of targeted PCK1 therapy in combination with chemotherapy and immunotherapy for cancer treatment.

Aberrant expression of MRAS and HEG1 as the biomarkers for osimertinib resistance in LUAD

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are the most applied targeted therapy for EGFR-mutant lung adenocarcinoma (LUAD). The third-generation EGFR-TKI, osimertinib, is widely used throughout lung cancer treatment, with single or combination modes. One of the main barriers in osimertinib treatment is the acquired resistance and mechanisms are not fully understood. Gene expression other than genetic mutations might predict drug response and mediate resistance occurrence. We analyzed six datasets of osimertinib-resistant LUAD cells from the Gene Expression Omnibus (GEO) database and identified two hub genes, named MRAS and HEG1. We found that the expression mode of MRAS/HEG1 in LUAD was osimertinib-dependent and contributed to drug resistance. We also explored potential mechanisms of hub genes related osimertinib resistance and emphasized the M2 infiltration involved. Moreover, potential therapeutic agents conquering MRAS/HEG1-related resistance were also identified. In conclusion, MRAS and HEG1 might be responsible for osimertinib resistance and could be promising prognostic biomarkers for osimertinib response in LUAD, which might provide insights into therapeutic strategies.

Delivery of SiRNA-PD-L1 by attenuated Salmonella in combination with oxaliplatin in a hepatocellular carcinoma mouse model

Oxaliplatin is currently used for chemotherapy in patients with hepatocellular carcinoma, but its increasing tolerance to tumours over time limits its clinical application. Studies have shown that high PD-L1 expression promotes the polarization of M2 macrophages. The increased infiltration of M2 macrophages, including those in HCC, is positively correlated with poor prognosis in various solid tumours. We found that oxaliplatin promoted the expression of PD-L1 in liver cancer cells, which might be attributed partly to the tolerance of tumours to oxaliplatin. Therefore, in this study, we explored the antitumour effect of attenuated Salmonella carrying siRNA-PD-L1 combined with oxaliplatin via Western blotting, immunohistochemistry, immunofluorescence, and flow cytometry. The results revealed that attenuated Salmonella carrying siRNA-PD-L1 combined with oxaliplatin more significantly inhibited tumour growth in tumour-bearing mice, suppressed the expression of PD-L1 in tumour tissue, increased the apoptosis of tumour cells and the expression of the tumour-related protein cleaved-caspase3, and increased the infiltration of M1 macrophages and T lymphocytes in tumour tissues. Moreover, the combination therapy increased the activation of T cells and the number of T lymphocytes and NK cells in the spleens of the mice and improved the overall antitumour immune response in the mice. Our results confirmed that attenuated Salmonella harbouring siRNA-PD-L1 combined with oxaliplatin had a significant antitumour effect and did not increase the incidence of toxic side effects, providing a theoretical reference for addressing oxaliplatin tolerance in the treatment of hepatocellular carcinoma.

Targeting non-histone methylation in gastrointestinal cancers: From biology to clinic

Gastrointestinal (GI) cancers, encompassing a range of malignancies within the digestive tract, present significant challenges in both diagnosis and treatment, reflecting a dire need for innovative therapeutic strategies. This article delves into the profound influence of non-histone methylation on the pathogenesis and evolution of gastrointestinal (GI) cancers. Non-histone proteins, undergoing methylation by enzymes such as Protein Arginine Methyltransferases (PRMTs) and Lysine Methyltransferases (KMTs), play pivotal roles in cellular signaling, metabolism, chromatin remodeling, and other processes crucial for cancer development. This review illuminates the complex mechanisms by which non-histone methylation affects key aspects of tumor biology, including oncogenesis, growth, proliferation, invasion, migration, metabolic reprogramming, and immune escape in GI malignancies. Highlighting recent discoveries, this work underscores the importance of non-histone methylation in cancer biology and its potential as a target for innovative therapeutic strategies aimed at improving outcomes for patients with GI cancers.

Developing pioneering pharmacological strategies with CRISPR/Cas9 library screening to overcome cancer drug resistance

Cancer drug resistance is a major obstacle to the effectiveness of chemoradiotherapy, targeted therapy, and immunotherapy. CRISPR/Cas9 library screening has emerged as a powerful genetic screening tool with significant potential to address this challenge. This review provides an overview of the development, methodologies, and applications of CRISPR/Cas9 library screening in the study of cancer drug resistance. We explore its role in elucidating resistance mechanisms, identifying novel anticancer targets, and optimizing treatment strategies. The use of in vivo single-cell CRISPR screens is also highlighted for their capacity to reveal T-cell regulatory networks in cancer immunotherapy. Challenges in clinical translation are discussed, including off-target effects, complexities in data interpretation, and model selection. Despite these obstacles, continuous technological advancements indicate a promising future for CRISPR/Cas9 library screening in overcoming cancer drug resistance.

Decoding the epitranscriptome: a new frontier for cancer therapy and drug resistance

As the role of RNA modification in gene expression regulation and human diseases, the "epitranscriptome" has been shown to be an important player in regulating many physiological and pathological processes. Meanwhile, the phenomenon of cancer drug resistance is becoming more and more frequent, especially in the case of cancer chemotherapy resistance. In recent years, research on relationship between post-transcriptional modification and cancer including drug resistance has become a hot topic, especially the methylation of the sixth nitrogen site of RNA adenosine-m6A (N6-methyladenosine). m6A modification is the most common post-transcriptional modification of eukaryotic mRNA, accounting for 80% of RNA methylation modifications. At the same time, several other modifications of RNA, such as N1-methyladenosine (m1A), 5-methylcytosine (m5C), 3-methylcytosine (m3C), pseudouridine (Ψ) and N7-methylguanosine (m7G) have also been demonstrated to be involved in cancer and drug resistance. This review mainly discusses the research progress of RNA modifications in the field of cancer and drug resistance and targeting of m6A regulators by small molecule modulators, providing reference for future study and development of combination therapy to reverse cancer drug resistance.

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.

Type I arginine methyltransferases play crucial roles in development and pathogenesis of Phytophthora capsici

Phytophthora capsici, a pathogenic oomycete, poses a serious threat to global vegetable production. This study investigated the role of protein arginine methylation, a notable post-translational modification, in the epigenetic regulation of P. capsici. We identified and characterized five protein arginine methyltransferases (PRMTs) in P. capsici, with a focus on four putative type I PRMTs exhibiting similar functional domain. Deletion of PcPRMT3, a homolog of PRMT3, significantly affected mycelial growth, asexual spore development, pathogenicity, and stress responses in P. capsici. Transcriptome analyses indicated that absence of PcPRMT3 disrupted multiple biological pathways. The PcPRMT3 deletion mutant displayed heightened susceptibility to oxidative stress, correlated with the downregulation of genes involved in peroxidase and peroxisome activities. Additionally, PcPRMT3 acted as a negative regulator, modulating the transcription levels of specific elicitins, which in turn affects the defense response of host plant against P. capsici. Furthermore, PcPRMT3 was found to affect global arginine methylation levels in P. capsici, implying potential alterations in the functions of its substrate proteins.

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in hematological diseases

The oncofetal mRNA-binding protein IGF2BP1 belongs to a conserved family of RNA-binding proteins. It primarily promotes RNA stability, regulates translation and RNA localization, and mediates gene expression through its downstream effectors. Numerous studies have demonstrated that IGF2BP1 plays crucial roles in embryogenesis and carcinogenesis. IGF2BP1-modulated cell proliferation, invasion, and chemo-resistance in solid tumors have attracted researchers' attention. Additionally, several studies have highlighted the importance of IGF2BP1 in hematologic malignancies and hematological genetic diseases, positioning it as a promising therapeutic target for hematological disorders. However, there is a lack of systematic summaries regarding the IGF2BP1 gene within the hematological field. In this review, we provide a comprehensive overview of the discovery and molecular structure of IGF2BP1, along with recent studies on its role in regulating embryogenesis. We also focus on the mechanisms by which IGF2BP1 regulates hematological malignancies through its interactions with its targeted mRNAs. Furthermore, we systematically elucidate the function and mechanism of IGF2BP1 in promoting fetal hemoglobin expression in adult hematopoietic stem/progenitor cells. Finally, we discuss the limitations and challenges of IGF2BP1 as a therapeutic target, offering insights into its prospects.

Targeting PRMT3 impairs methylation and oligomerization of HSP60 to boost anti-tumor immunity by activating cGAS/STING signaling

Immune checkpoint blockade (ICB) has emerged as a promising therapeutic option for hepatocellular carcinoma (HCC), but resistance to ICB occurs and patient responses vary. Here, we uncover protein arginine methyltransferase 3 (PRMT3) as a driver for immunotherapy resistance in HCC. We show that PRMT3 expression is induced by ICB-activated T cells via an interferon-gamma (IFNγ)-STAT1 signaling pathway, and higher PRMT3 expression levels correlate with reduced numbers of tumor-infiltrating CD8+ T cells and poorer response to ICB. Genetic depletion or pharmacological inhibition of PRMT3 elicits an influx of T cells into tumors and reduces tumor size in HCC mouse models. Mechanistically, PRMT3 methylates HSP60 at R446 to induce HSP60 oligomerization and maintain mitochondrial homeostasis. Targeting PRMT3-dependent HSP60 methylation disrupts mitochondrial integrity and increases mitochondrial DNA (mtDNA) leakage, which results in cGAS/STING-mediated anti-tumor immunity. Lastly, blocking PRMT3 functions synergize with PD-1 blockade in HCC mouse models. Our study thus identifies PRMT3 as a potential biomarker and therapeutic target to overcome immunotherapy resistance in HCC.

Deficiency of betaine-homocysteine methyltransferase activates glucose-6-phosphate dehydrogenase (G6PD) by decreasing arginine methylation of G6PD in hepatocellular carcinogenesis

Betaine-homocysteine methyltransferase (BHMT) regulates protein methylation and is correlated with tumorigenesis; however, the effects and regulation of BHMT in hepatocarcinogenesis remain largely unexplored. Here, we determined the clinical significance of BHMT in the occurrence and progression of hepatocellular carcinoma (HCC) using tissue samples from 198 patients. BHMT was to be frequently found (86.6%) expressed at relatively low levels in HCC tissues and was positively correlated with the overall survival of patients with HCC. Bhmt overexpression effectively suppressed several malignant phenotypes in hepatoma cells in vitro and in vivo, whereas complete knockout of Bhmt (Bhmt-/-) produced the opposite effect. We combined proteomics, metabolomics, and molecular biological strategies and detected that Bhmt-/- promoted hepatocarcinogenesis and tumor progression by enhancing the activity of glucose-6-phosphate dehydrogenase (G6PD) and PPP metabolism in DEN-induced HCC mouse and subcutaneous tumor-bearing models. In contrast, restoration of Bhmt with an AAV8-Bhmt injection or pharmacological inhibition of G6PD attenuated hepatocarcinogenesis. Additionally, coimmunoprecipitation identified monomethylated modifications of the G6PD, and BHMT regulated the methylation of G6PD. Protein sequence analysis, generation and application of specific antibodies, and site-directed mutagenesis indicated G6PD methylation at the arginine residue 246. Furthermore, we established bidirectionally regulated BHMT cellular models combined with methylation-deficient G6PD mutants to demonstrate that BHMT potentiated arginine methylation of G6PD, thereby inhibiting G6PD activity, which in turn suppressed hepatocarcinogenesis. Taken together, this study reveals a new methylation-regulatory mechanism in hepatocarcinogenesis owing to BHMT deficiency, suggesting a potential therapeutic strategy for HCC treatment.

Intricate effects of post-translational modifications in liver cancer: mechanisms to clinical applications

Liver cancer is a significant global health challenge, with hepatocellular carcinoma (HCC) being the most prevalent form, characterized by high incidence and mortality rates. Despite advances in targeted therapies and immunotherapies, the prognosis for advanced liver cancer remains poor. This underscores the urgent need for a deeper understanding of the molecular mechanisms underlying HCC to enable early detection and the development of novel therapeutic strategies. Post-translational modifications (PTMs) are crucial regulatory mechanisms in cellular biology, affecting protein functionality, interactions, and localization. These modifications, including phosphorylation, acetylation, methylation, ubiquitination, and glycosylation, occur after protein synthesis and play vital roles in various cellular processes. Recent advances in proteomics and molecular biology have highlighted the complex networks of PTMs, emphasizing their critical role in maintaining cellular homeostasis and disease pathogenesis. Dysregulation of PTMs has been associated with several malignant cellular processes in HCC, such as altered cell proliferation, migration, immune evasion, and metabolic reprogramming, contributing to tumor growth and metastasis. This review aims to provide a comprehensive understanding of the pathological mechanisms and clinical implications of various PTMs in liver cancer. By exploring the multifaceted interactions of PTMs and their impact on liver cancer progression, we highlight the potential of PTMs as biomarkers and therapeutic targets. The significance of this review lies in its potential to inform the development of novel therapeutic approaches and improve prognostic tools for early intervention in the fight against liver cancer.

Research Progress on the Role of Epigenetic Methylation Modification in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) stands as the prevailing form of primary liver cancer, characterized by a poor prognosis and high mortality rate. A pivotal factor in HCC tumorigenesis is epigenetics, specifically the regulation of gene expression through methylation. This process relies significantly on the action of proteins that modify methylation, including methyltransferases, their associated binding proteins, and demethylases. These proteins are crucial regulators, orchestrating the methylation process by regulating enzymes and their corresponding binding proteins. This orchestration facilitates the reading, binding, detection, and catalysis of gene methylation sites. Methylation ences the development, prolisignificantly influferation, invasion, and prognosis of HCC. Furthermore, methylation modification and its regulatory mechanisms activate distinct biological characteristics in HCC cancer stem cells, such as inducing cancer-like differentiation of stem cells. They also influence the tumor microenvironment (TME) in HCC, modulate immune responses, affect chemotherapy resistance in HCC patients, and contribute to HCC progression through signaling pathway feedback. Given the essential role of methylation in genetic information, it holds promise as a potential tool for the early detection of HCC and as a target to improve drug resistance and promote apoptosis in HCC cells.

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.

Identification of protein methyltransferases 5 associated with ferroptosis and immune cell infiltration of head and neck squamous cell carcinoma

Head and neck tumors are malignant tumors that appear in the head and neck. Although much progress has been made in the treatment of head and neck tumors, many challenges remain. The prognosis of some advanced cases remains poor and survival and quality of life after treatment face certain limitations. Therefore, further research into the pathogenesis and treatment options for head and neck tumors is important in order to improve the prognosis and quality of life of patients. The Protein Arginine Methyltransferase (PRMT) family is a class of enzymes that are responsible for adding methyl groups to arginine residues in proteins. PRMT family members play important roles in regulating many cellular processes, such as transcriptional regulation, signaling, and cell cycle regulation. Recent studies have shown that the PRMT family also plays an important function in tumorigenesis and development. Here, we found that PRMT family members are significantly overexpressed in head and neck tumors and that PRMT5 may serve as an independent prognostic factor in head and neck tumors. We found that PRMT5-regulated differential genes were significantly enriched in tumor-associated signaling pathways such as IL-17 and p53. And we also found that the expression of PRMT5 in head and neck tumors was significantly correlated with immune cell infiltration, m6A as well as the expression of ferroptosis-related genes, and drug sensitivity. These results suggest that PRMT may play an important role in the development of head and neck tumors.

Loss of lncRNA LINC01056 leads to sorafenib resistance in HCC

BACKGROUND AND AIMS

Sorafenib is a major nonsurgical option for patients with advanced hepatocellular carcinoma (HCC); however, its clinical efficacy is largely undermined by the acquisition of resistance. The aim of this study was to identify the key lncRNA involved in the regulation of the sorafenib response in HCC.

MATERIALS AND METHODS

A clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) single-guide RNA (sgRNA) synergistic activation mediator (SAM)-pooled lncRNA library was applied to screen for the key lncRNA regulated by sorafenib treatment. The role of the identified lncRNA in mediating the sorafenib response in HCC was examined in vitro and in vivo. The underlying mechanism was delineated by proteomic analysis. The clinical significance of the expression of the identified lncRNA was evaluated by multiplex immunostaining on a human HCC microtissue array.

RESULTS

CRISPR/Cas9 lncRNA library screening revealed that Linc01056 was among the most downregulated lncRNAs in sorafenib-resistant HCC cells. Knockdown of Linc01056 reduced the sensitivity of HCC cells to sorafenib, suppressing apoptosis in vitro and promoting tumour growth in mice in vivo. Proteomic analysis revealed that Linc01056 knockdown in sorafenib-treated HCC cells induced genes related to fatty acid oxidation (FAO) while repressing glycolysis-associated genes, leading to a metabolic switch favouring higher intracellular energy production. FAO inhibition in HCC cells with Linc01056 knockdown significantly restored sensitivity to sorafenib. Mechanistically, we determined that PPARα is the critical molecule governing the metabolic switch upon Linc01056 knockdown in HCC cells and indeed, PPARα inhibition restored the sorafenib response in HCC cells in vitro and HCC tumours in vivo. Clinically, Linc01056 expression predicted optimal overall and progression-free survival outcomes in HCC patients and predicted a better sorafenib response. Linc01056 expression indicated a low FAO level in HCC.

CONCLUSION

Our study identified Linc01056 as a critical epigenetic regulator and potential therapeutic target in the regulation of the sorafenib response in HCC.

Efficacy and Safety of HepaSphere Drug-Eluting Bead Transarterial Chemoembolization Combined with Hepatic Arterial Infusion Chemotherapy as the Second-Line Treatment in Advanced Hepatocellular Carcinoma

PURPOSE

Recently, hepatic arterial infusion chemotherapy (HAIC) has also gained popularity for hepatocellular carcinoma (HCC). Several studies have compared HAIC and Transarterial chemoembolization (TACE). However, comparisons between TACE plus HAIC and HAIC are rarely reported. Here, we evaluated the performance of HepaSphere DEB-TACE combined with HAIC (Hepa-HAIC) compared to HAIC in patients with advanced HCC.

PATIENTS AND METHODS

In this retrospective study, we enrolled 167 patients diagnosed with advanced HCC and treated at Peking University Cancer Hospital from May 2018 to May 2022. The cohort comprised 74 patients who received HepaSphere DEB-TACE combined with HAIC-FOLFOX (Hepa-HAIC) and 93 patients who received HAIC-FOLFOX. Over 60% of patients received prior treatments. To avoid selection bias, propensity score matching was applied to the efficacy and safety analyses. The primary endpoints are progression-free survival (PFS) and overall survival (OS); the secondary endpoints include objective response rate (ORR), disease control rate (DCR), and safety.

RESULTS

Propensity-matching yielded 48 pairs, and group baselines were almost equal after matching. Median PFS and median OS were both higher in the matched Hepa-HAIC cohort (median PFS: 8.9 vs 5.8 months, p = 0.035; median OS: 22.4 vs 9.5 months, p = 0.027), which was consistent with pre-matching analysis. The ORR in the Hepa-HAIC and HAIC cohorts was 75.0% and 37.5%, respectively; the DCR was 93.8% after Hepa-HAIC and 81.3% after HAIC. There was no treatment-related death. Grade 3-4 ALT elevation was more frequent in the Hepa-HAIC group (33.3% vs 8.3%, p = 0.003), while vomiting was more frequent in the HAIC group (29.2% vs 12.5%, p = 0.084).

CONCLUSION

The Hepa-HAIC group is superior to the HAIC group in metrics of PFS, OS, ORR, and DCR, which indicates the combination of HepaSphere DEB-TACE and HAIC may lead to improved outcomes with a comparable safety profile in advanced HCC.

HSP90a promotes the resistance to oxaliplatin in HCC through regulating IDH1-induced cell competition

Though burgeoning research manifests that cell competition, an essential selection and quality control mechanism for maintaining tissue or organ growth and homeostasis in multicellular organisms, is closely related to tumorigenesis and development, the mechanism of cell competition associated with tumor drug resistance remains elusive. In the study, we uncovered that oxaliplatin-resistant hepatocellular carcinoma (HCC) cells exhibit a pronounced competitive advantage against their sensitive counterparts, which is related to lipid takeover of resistant cells from sensitive cells. Of note, such lipid takeover is dependent on the existence of isocitrate dehydrogenase 1 (IDH1) in resistant HCC cells. Mechanistically, IDH1 activity is regulated by heat shock protein 90 alpha (HSP90α) through binding with each other, which orchestrates the expressions of lipid metabolic enzymes and lipid accumulation in resistant HCC cells. Our results suggest that HCC cell competition-driven chemoresistance can be regulated by HSP90α/IDH1-mediated lipid metabolism, which may serve as a promising target for overcoming drug resistance in HCC.

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.

Crosstalk between ferroptosis and cuproptosis: From mechanism to potential clinical application

Ferroptosis and cuproptosis, regulated forms of cell death resulting from metal ion accumulation, are closely related in terms of occurrence, cell metabolism, signaling pathways, and drug resistance. Notably, it is now understood that these processes play crucial roles in regulating physiological and pathological processes, especially in tumor development. Consequently, ferroptosis and cuproptosis have gained increasing significance as potential targets for anti-cancer drug development. This article systematically outlines the molecular mechanisms and cross-talk components of both ferroptosis and cuproptosis, elucidating their impacts on cancer. Furthermore, it investigates the clinical perspective of targeted ferroptosis and cuproptosis in cancer chemotherapy, immunotherapy, and radiotherapy. Our discussion extends to a comparative analysis of nanoparticles developed based on the mechanisms of ferroptosis and cuproptosis in cancer, contrasting them with current conventional therapies. Opportunities and challenges in cancer treatment are explored, emphasizing the potential therapeutic direction of co-targeting ferroptosis and cuproptosis. The article also attempts to analyze the clinical applications of this co-targeting approach for cancer treatment while summarizing the existing barriers that require overcoming.

PRMT3 methylates HIF-1α to enhance the vascular calcification induced by chronic kidney disease

BACKGROUND

Medial vascular calcification is commonly identified in chronic kidney disease (CKD) patients and seriously affects the health and life quality of patients. This study aimed to investigate the effects of protein arginine methyltransferase 3 (PRMT3) on vascular calcification induced by CKD.

METHODS

A mice model of CKD was established with a two-step diet containing high levels of calcium and phosphorus. Vascular smooth muscle cells (VSMCs) were subjected to β-glycerophosphate (β-GP) treatment to induce the osteogenic differentiation as an in vitro CKD model.

RESULTS

PRMT3 was upregulated in VSMCs of medial artery of CKD mice and β-GP-induced VSMCs. The inhibitor of PRMT3 (SGC707) alleviated the vascular calcification and inhibited the glycolysis of CKD mice. Knockdown of PRMT3 alleviated the β-GP-induced osteogenic transfomation of VSMCs by the repression of glycolysis. Next, PRMT3 interacted with hypoxia-induced factor 1α (HIF-1α), and the knockdown of PRMT3 downregulated the protein expression of HIF-1α by weakening its methylation. Gain of HIF-1α reversed the PRMT3 depletion-induced suppression of osteogenic differentiation and glycolysis of VSMCs.

CONCLUSION

The inhibitory role of PRMT3 depletion was at least mediated by the regulation of glycolysis upon repressing the methylation of HIF-1α.

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.

ATR-dependent ubiquitin-specific protease 20 phosphorylation confers oxaliplatin and ferroptosis resistance

Oxaliplatin (OXA) resistance is a major clinic challenge in hepatocellular carcinoma (HCC). Ferroptosis is a kind of iron-dependent cell death. Triggering ferroptosis is considered to restore sensitivity to chemotherapy. In the present study, we found that USP20 was overexpressed in OXA-resistant HCC cells. High expression of USP20 in HCC was associated with poor prognosis. USP20 contributes OXA resistance and suppress ferroptosis in HCC. Pharmacological inhibition or knockdown of USP20 triggered ferroptosis and increased the sensitivity of HCC cells to OXA both in vitro and in vivo. Coimmunoprecipitation results revealed that the UCH domain of USP20 interacted with the N terminal of SLC7A11. USP20 stabilized SLC7A11 via removing K48-linked polyubiquitination of SLC7A11 protein at K30 and K37. Most importantly, DNA damage-induced ATR activation was required for Ser132 and Ser368 phosphorylation of USP20. USP20 phosphorylation at Ser132 and Ser368 enhanced its stability and thus conferred OXA and ferroptosis resistance of HCC cells. Our study reveals a previously undiscovered association between OXA and ferroptosis and provides new insight into mechanisms regarding how DNA damage therapies always lead to therapeutic resistance. Therefore, targeting USP20 may mitigate the development of drug resistance and promote ferroptosis of HCC in patients receiving chemotherapy.