PRMT1 Sustains De Novo Fatty Acid Synthesis by Methylating PHGDH to Drive Chemoresistance in Triple-Negative Breast Cancer

SOX12 promotes serine synthesis and tumor progression in endometrial cancer

Studies have demonstrated that the sex-determining region Y-box 12 (SOX12), a key oncogene, is highly expressed in various tumors and is associated with poor prognosis. Unfortunately, the effect of SOX12 in endometrial cancer (EC) remains unclear. Here, we discovered that SOX12 expression was significantly elevated in EC tissues from advanced-stage patients and patients who died. Additionally, high expression of SOX12 was shown to predict poor overall survival (OS) and recurrence-free survival (RFS), indicating that SOX12 is an independent prognostic factor for patients with EC. Furthermore, the overexpression or knockdown of SOX12 significantly enhanced or inhibited the activity, proliferation, migration, invasion ability, serine synthesis pathway (SSP) activity and metabolism, respectively, of EC cells. Moreover, overexpression of SOX12 significantly promoted the growth and malignant progression of subcutaneously transplanted tumors, facilitated the formation of lung metastatic nodules, and ultimately reduced the survival time of nude mice. In contrast, stable suppression of SOX12 markedly inhibited the growth of subcutaneous grafts and the formation of lung metastatic nodules in introduced via the tail vein, while also increasing the survival time of nude mice. Mechanistically, SOX12 directly binds to the promoter of the target gene 3-phosphoglycerate dehydrogenase (PHGDH), activating its transcription and enhancing the SSP and metabolism, which ultimately contributes to the malignant progression of EC. Surprisingly, we found that the combination of serine deprivation and SOX12 knockdown had a more pronounced effect on inhibiting the malignant progression of EC in vivo and in vitro. In summary, our study not only enhances the understanding of the carcinogenic mechanisms associated with SOX12 but also presents a potential strategy for molecularly targeted therapy in EC.

Glioblastoma cells secrete ICAM1 via FASN signaling to promote glioma-associated macrophage infiltration

Glioma-associated macrophages (GAMs) constitute the most abundant subset of immune cells in the glioblastoma (GBM) microenvironment, but the underlying mechanism of intense infiltration needs to be elucidated. In this study, we found that GBM cells secrete ICAM1 via FASN signaling to promote GAM infiltration. FASN expression is correlated with GAM density in GBM patients. In vitro experiments revealed that FASN regulates the type-I interferon pathway, particularly STAT1 expression. Moreover, disrupting FASN-STAT1 signaling through the overexpression or inhibition of FASN or STAT1 in GBM cells strongly influences microglial recruitment. Additionally, ICAM1 acts as a direct transcriptional candidate of FASN-STAT1 and a paracrine soluble factor, recruiting microglia to GBM tumors. This study revealed crosstalk between GBM cells and GAMs through FASN-STAT1-ICAM1 signaling to promote microglial infiltration, suggesting potential strategies for treating GBM patients.

Palbociclib stimulates CD8+ T cell response in triple-negative breast cancer via regulating phosphoglycerate dehydrogenase

CDK4/6 inhibitors are applied for the treatment of breast cancer. The purpose of this study was to explore the effects of palbociclib (PALB) on triple-negative breast cancer. An in vivo assay was applied to determine the effects of PALB on breast cancer. Gene expression was detected using immunohistochemistry. mRNA levels were detected using reverse transcription-quantitative PCR. Protein expression was detected using western blot. The expansion of CD8+ T cell subsets was detected using flow cytometry. We found that PALB treatment promoted the persistence of CD8+ T cells, manifested by the maintenance of stem-like CD8+ T cells and effector T cells. Moreover, PALB downregulated PHGDH, high levels of which predicted poor prognosis of breast cancer patients. Moreover, overexpression of PHGDH antagonized the effects of PALB and suppressed the persistence of CD8+ T cells. Additionally, PALB enhanced the effects of anti-PD1 immunotherapy and suppressed the tumor growth of breast cancer. In summary, PALB promoted the maintenance of CD8+ memory precursors in breast cancer via downregulating PHGDH.

Reprogramming of fatty acid metabolism in thyroid cancer: Potential targets and mechanisms

Thyroid cancer (TC) is one of the most common endocrine system tumors, and its incidence continues to increase worldwide. Although most TC patients have a good prognosis, especially with continuous advancements in surgery, radioactive iodine therapy, chemotherapy, endocrine therapy and targeted therapy, the effectiveness of disease treatment has significantly improved. However, there are still some cases with a higher risk of death and greater aggressiveness. In these more challenging advanced or highly aggressive cases, tyrosine kinase inhibitors appear to be an effective treatment option. Unfortunately, these drugs are less than ideal in terms of efficacy because of their toxicity and potential for intrinsic or acquired resistance. Therefore, exploring new strategies targeting the metabolic characteristics of TC cells and overcoming drug resistance barriers in existing treatments have become key topics in the current field of TC research. In recent years, lipid metabolic reprogramming has gained attention as an important aspect of cancer development. Lipid metabolic reprogramming not only participates in the formation of the cell membrane structure, but also plays an important role in signal transduction and promoting cell proliferation. In particular, fatty acid (FA) metabolic reprogramming has attracted widespread attention and plays an important role in multiple aspects such as tumor growth, metastasis, enhanced invasive ability, immune escape, and drug resistance. Although TC is considered a disease that is highly dependent on specific types of metabolic activities, a comprehensive understanding of the specific mechanism of action of FA metabolic reprogramming in this process is lacking. This article aims to review how FA metabolic reprogramming participates in the occurrence and development of TC, focusing on the impact of abnormal FA metabolic pathways and changes in the expression and regulation of related genes over the course of this disease. By examining the complex interactions between FA metabolic disorders and carcinogenic signaling pathways in depth, we aim to identify new therapeutic targets and develop more precise and effective treatments for TC.

PRMT1-Mediated SWI/SNF Complex Recruitment via SMARCC1 Drives IGF2BP2 Transcription to Enhance Carboplatin Resistance in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a malignancy with poor prognosis and chemotherapy resistance. Here, protein arginine methyltransferase 1 (PRMT1) is identified as a key driver of carboplatin (CBP) resistance in HNSCC. Analyses of clinical samples, cell lines, patient-derived organoids, and xenograft models reveal that PRMT1 promotes tumor growth and CBP resistance through a novel, methyltransferase-independent mechanism. Conditional PRMT1 knockout suppresses tumorigenesis and enhances CBP sensitivity in vivo, highlighting its essential role in HNSCC progression. Mechanistically, PRMT1 recruits the SWI/SNF chromatin remodeling complex via direct interaction with SMARCC1, leading to the transcriptional activation of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), which enhances CBP resistance and tumor growth. Notably, this function is independent of PRMT1's enzymatic activity, distinguishing it from its well-established roles in arginine methylation. Furthermore, pre-B-cell leukemia homeobox 2 (PBX2) is identified as an upstream transcriptional activator that binds the PRMT1 promoter, driving its overexpression and reinforcing this oncogenic network. Clinically, high PBX2, PRMT1, SMARCC1, and IGF2BP2 expression correlates with malignant progression and poor prognosis in HNSCC patients. This study uncovers a previously unrecognized non-catalytic function of PRMT1 and highlights the PBX2-PRMT1-SWI/SNF-IGF2BP2 axis as a potential therapeutic target for overcoming CBP resistance in HNSCC.

Generation of human adult hepatocyte organoids with metabolic functions

Proliferating hepatocytes often undergo ductal metaplasia to balance the energy trade-off between cellular functions and replication, hindering the expansion of human adult hepatocytes with functional competency1. Here we demonstrate that the combined activation of Wnt and STAT3 signalling enables long-term self-renewal of human adult hepatocyte organoids. YAP activation facilitates hepatocyte proliferation but commits it towards the biliary duct lineage. By contrast, STAT3 activation by oncostatin M induces hepatocyte proliferation while counteracting ductal metaplasia and maintaining the hepatic identity. Xenotransplanted hepatocyte organoids repopulate the recipient mouse liver and reconstitute the metabolic zonation structure. Upon niche factor removal and hormone supplementation, hepatocyte organoids form cord-like structures with bile canalicular networks and exhibit major liver metabolic functions comparable to those of in vivo hepatocytes. Hepatocyte organoids are amenable to gene editing, prompting functional modelling of inherent metabolic liver diseases. The new culture system offers a promising avenue for developing therapeutic strategies against human liver diseases.

Targeting protein arginine methyltransferases in breast cancer: Promising strategies

Protein arginine methyltransferases (PRMTs) catalyze arginine methylation, an essential protein posttranslational modification involved in a variety of biological processes, such as transcription, RNA splicing and the DNA damage response (DDR), protein stability, and signal transduction. Due to their significant roles in these processes, PRMTs have emerged as promising therapeutic targets in cancer. Among all cancer types, breast cancer has been the most extensively studied in relation to PRMTs dysregulation. Previous studies have reported that several PRMTs are overexpressed in breast cancer and play critical roles in tumor growth, metastasis, and the maintenance of breast cancer stem cells. Moreover, an increasing number of PRMT inhibitors are undergoing clinical trials for breast cancer treatment, demonstrating significant progress. This review aims to provide a comprehensive overview of the biological functions of PRMTs in breast cancer and to summarize the latest clinical developments of PRMT inhibitors for cancer therapy.

Glycolysis reprogramming in CAFs promotes oxaliplatin resistance in pancreatic cancer through circABCC4 mediated PKM2 nuclear translocation

Cancer-associated fibroblasts (CAFs) play a key role in oxaliplatin resistance in pancreatic ductal adenocarcinoma (PDAC). However, the potential mechanisms by which CAFs promote chemotherapy resistance have not yet been explored. In this study, we found that circABCC4 (hsa_circ_0030582) was positively correlated with poor platinum-chemotherapeutic response and a shorter progression-free survival (PFS) time in late-stage PDAC patients. CircABCC4 enhanced the ability of CAFs to induce oxaliplatin resistance in pancreatic cancer cells through glycolysis reprogramming. Mechanistically, circABCC4 enhanced the interaction between PKM2 and KPNA2 to promote PKM2 nuclear translocation in CAFs, leading to the transcription of glycolysis-related genes. The glycolytic reprogramming of CAFs promoted the secretion of IL-8, which in turn enhanced DNA damage repair in pancreatic cancer. Blocking PKM2 nuclear translocation abolished circABCC4-driven oxaliplatin resistance of pancreatic cancer in vivo. Collectively, our study reveals a circRNA-mediated glycolysis reprogramming of CAFs to induce oxaliplatin resistance and highlights circABCC4 as a potential therapeutic target.

The role of PRMT1 in cellular regulation and disease: Insights into biochemical functions and emerging inhibitors for cancer therapy

Protein Arginine Methyltransferase 1 (PRMT1), a primary protein arginine methyltransferase, plays a pivotal role in cellular regulation, influencing processes such as gene expression, signal transduction, and cell differentiation. Dysregulation of PRMT1 has been linked to the development of various cancers, establishing it as a key target for therapeutic intervention. This review synthesizes the biochemical characteristics, structural domains, and functional mechanisms of PRMT1, focusing on its involvement in tumorigenesis. Additionally, the development and efficacy of emerging PRMT1 inhibitors as potential cancer therapies are examined. By employing molecular modeling and insights from existing literature, this review posits that targeting PRMT1's methyltransferase activity could disrupt cancer progression, providing valuable insights for future drug development.

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.

Metabolic changes of human induced pluripotent stem cell-derived cardiomyocytes and teratomas after transplantation

Cardiac regenerative therapy using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) has been applied in clinical settings. Herein, we aimed to investigate the in vivo metabolic profiles of hiPSC-CM grafts. RNA sequencing and imaging mass spectrometry were performed in the present study, which revealed that hiPSC-CM grafts matured metabolically over time after transplantation. Glycolysis, which was active in the hiPSC-CM grafts immediately after transplantation, shifted to fatty acid oxidation. Additionally, we examined the metabolic profile of teratomas that may form when non-CMs, including undifferentiated human induced pluripotent stem cells (hiPSCs), remain in transplanted cells. The upregulated gene expression of amino acid transporters and the high accumulation of amino acids, such as methionine and aromatic amino acids, were observed in the teratomas. We show that subcutaneous teratomas derived from undifferentiated hiPSCs can be detected in vivo using positron emission tomography with [18F]fluorophenylalanine ([18F]fPhe). These results provided insights into the clinical application of cardiac regenerative therapy.

KLF1 Activates RAC3 to Mediate Fatty Acid Synthesis and Enhance Cisplatin Resistance in Bladder Cancer Cells

While cisplatin remains a frontline treatment for bladder cancer (BCa), the onset of resistance greatly hampers its effectiveness. RAC3 is closely linked to chemoresistance in cancer cells, but its specific role in cisplatin resistance within BCa is still elusive. RAC3 expression in BCa was analyzed using bioinformatics and quantitative polymerase chain reaction (qPCR). The gene set enrichment analysis (GSEA) identified RAC3-enriched pathways and the correlation between RAC3 and fatty acid synthase (FASN), a gene involved in fatty acid synthesis. Potential upstream transcription factors of RAC3 were predicted and their interaction with RAC3 was confirmed via dual-luciferase and chromatin immunoprecipitation (ChIP) assays. T24/DDP, a cisplatin-resistant BCa cell line, was established to probe into the regulatory role of RAC3 in cisplatin resistance. Cell proliferation was evaluated by colony formation and the IC50 values after cisplatin treatment were determined using cell counting kit-8 (CCK-8). The levels of free fatty acids and triglycerides (TGs), as well as the expression of DGAT2 and FASN proteins, were measured to gauge the extent of fatty acid synthesis in cells. Elevated expression of RAC3 was observed in BCa and the cisplatin-resistant BCa cells (T24/DDP). The knockdown of RAC3 within T24/DDP cells was demonstrated to counteract cisplatin resistance. Subsequent analyses identified RAC3 as being notably enriched in the fatty acid synthesis pathway, with Kruppel-like factor 1 (KLF1) emerging as a key upstream regulator. The overexpression of RAC3 was correlated with increased cisplatin resistance in T24/DDP cells, an effect that was mitigated by the addition of the FASN inhibitor, Orlistat. Furthermore, the downregulation of KLF1 suppressed RAC3 expression, disrupted fatty acid synthesis, and attenuated cisplatin resistance in T24/DDP cells. Conversely, the co-overexpression of RAC3 counteracted the effects conferred by KLF1 knockdown. Our study has validated that KLF1 activates RAC3 to mediate fatty acid synthesis and promote cisplatin resistance in BCa, suggesting the KLF1/RAC3 axis as a potential target for combating cisplatin-resistant BCa.

Methylation modification of non-histone proteins in breast cancer: an emerging targeted therapeutic strategy

Breast cancer is a major public health concern worldwide, being the most commonly diagnosed cancer among women and a leading cause of cancer-related deaths. Recent studies have highlighted the significance of non-histone methylation in breast cancer, which modulates the activity, interaction, localization, and stability of target proteins. This regulation affects critical processes such as oncogenesis, tumor growth, proliferation, invasion, migration, and immune responses. This review delves into the enzymes responsible for non-histone methylation, such as protein arginine methyltransferases (PRMTs), lysine methyltransferases (KMTs), and demethylases, and explores their roles in breast cancer. By elucidating the molecular mechanisms and functional consequences of non-histone methylation, this review aims to provide insights into novel therapeutic strategies targeting these pathways. The therapeutic potential of targeting non-histone methylation to overcome drug resistance and enhance treatment efficacy in breast cancer is also discussed, highlighting promising avenues for future research and clinical applications.

Role of PRMT1 and PRMT5 in Breast Cancer

Breast cancer is the most common cancer diagnosed in women worldwide. Early-stage breast cancer is curable in ~70-80% of patients, while advanced metastatic breast cancer is considered incurable with current therapies. Breast cancer is a highly heterogeneous disease categorized into three main subtypes based on key markers orientating specific treatment strategies for each subtype. The complexity of breast carcinogenesis is often associated with epigenetic modification regulating different signaling pathways, involved in breast tumor initiation and progression, particularly by the methylation of arginine residues. Protein arginine methyltransferases (PRMT1-9) have emerged, through their ability to methylate histones and non-histone substrates, as essential regulators of cancers. Here, we present an updated overview of the mechanisms by which PRMT1 and PRMT5, two major members of the PRMT family, control important signaling pathways impacting breast tumorigenesis, highlighting them as putative therapeutic targets.

The Interplay of Acetylation and Ubiquitination Controls PRMT1 Homeostasis

PRMT1 plays many important roles in both normal and disease biology, thus understanding it's regulation is crucial. Herein, we report the role of p300-mediated acetylation at K228 in triggering PRMT1 degradation through FBXL17-mediated ubiquitination. Utilizing mass-spectrometry, cellular biochemistry, and genetic code-expansion technologies, we elucidate a crucial mechanism independent of PRMT1 transcript levels. These results underscore the significance of acetylation in governing protein stability and expand our understanding of PRMT1 homeostasis. By detailing the molecular interplay between acetylation and ubiquitination involved in PRMT1 degradation, this work contributes to broader efforts in deciphering post-translational mechanisms that influence protein homeostasis.