Targeting RNA-binding motif protein 39 for arginine reduction: unveiling metabolic vulnerability in arginine-dependent liver cancer.

Cancer is increasingly acknowledged as a metabolic disease, characterized by metabolic reprogramming as its hallmark. However, the precise mechanisms behind this phenomenon and the factors contributing to tumorigenicity are still poorly understood. In a recent publication in Cell, Mossmann and colleague reported a study unveiling arginine as a molecule with second messenger-like properties that reshapes metabolism to facilitate the tumor development in hepatocellular carcinoma (HCC). Their research revealed that the RNA-binding motif protein 39 (RBM39)-mediated increase in asparagine synthesis results in increased arginine uptake. This establishes a positive feedback loop that sustains elevated levels of arginine and facilitates oncogenic metabolic reprogramming. Additionally, Mossmann et al. demonstrated that depleting RBM39 with indisulam effectively disrupts the proto-oncogenic metabolic reprogramming in HCC. This discovery presents a novel treatment strategy for arginine-dependent liver cancers.

Histone demethylase KDM4B accelerates the progression of glioblastoma via the epigenetic regulation of MYC stability.

BACKGROUND: Glioblastoma (GBM) is the most malignant and invasive human brain tumor. Histone demethylase 4B (KDM4B) is abnormally expressed in GBM, but the molecular mechanisms by which KDM4B affects the malignant tumor progression are not well defined. METHODS: GBM cell lines and xenograft tumor samples were subjected to quantitative PCR (qPCR), Western blot, immunohistochemical staining (IHC), as well as ubiquitination, immunoprecipitation (IP), and chromatin immunoprecipitation (ChIP) assays to investigate the role of KDM4B in the progression of GBM. RESULTS: Here, we report that KDM4B is an epigenetic activator of GBM progression. Abnormal expression of KDM4B is correlated with a poor prognosis in GBM patients. In GBM cell lines, KDM4B silencing significantly inhibited cell survival, proliferation, migration, and invasion, indicating that KDM4B is essential for the anchorage-independent growth and tumorigenic activity of GBM cells. Mechanistically, KDM4B silencing led to downregulation of the oncoprotein MYC and suppressed the expression of cell cycle proteins and epithelial-to-mesenchymal transition (EMT)-related proteins. Furthermore, we found that KDM4B regulates MYC stability through the E3 ligase complex SCFFBXL3+CRY2 and epigenetically activates the transcription of CCNB1 by removing the repressive chromatin mark histone H3 lysine 9 trimethylation (H3K9me3). Finally, we provide evidence that KDM4B epigenetically activates the transcription of miR-181d-5p, which enhances MYC stability. CONCLUSIONS: Our study has uncovered a KDM4B-dependent epigenetic mechanism in the control of tumor progression, providing a rationale for utilizing KDM4B as a promising therapeutic target for the treatment of MYC-amplified GBM.

Methylation across the central dogma in health and diseases: new therapeutic strategies.

The proper transfer of genetic information from DNA to RNA to protein is essential for cell-fate control, development, and health. Methylation of DNA, RNAs, histones, and non-histone proteins is a reversible post-synthesis modification that finetunes gene expression and function in diverse physiological processes. Aberrant methylation caused by genetic mutations or environmental stimuli promotes various diseases and accelerates aging, necessitating the development of therapies to correct the disease-driver methylation imbalance. In this Review, we summarize the operating system of methylation across the central dogma, which includes writers, erasers, readers, and reader-independent outputs. We then discuss how dysregulation of the system contributes to neurological disorders, cancer, and aging. Current small-molecule compounds that target the modifiers show modest success in certain cancers. The methylome-wide action and lack of specificity lead to undesirable biological effects and cytotoxicity, limiting their therapeutic application, especially for diseases with a monogenic cause or different directions of methylation changes. Emerging tools capable of site-specific methylation manipulation hold great promise to solve this dilemma. With the refinement of delivery vehicles, these new tools are well positioned to advance the basic research and clinical translation of the methylation field.

Targeting serine-glycine-one-carbon metabolism as a vulnerability in cancers.

The serine-glycine-one-carbon (SGOC) metabolic pathway is critical for DNA methylation, histone methylation, and redox homeostasis, in addition to protein, lipid, and nucleotide biosynthesis. The SGOC pathway is a crucial metabolic network in tumorigenesis, wherein the outputs are required for cell survival and proliferation and are particularly likely to be co-opted by aggressive cancers. SGOC metabolism provides an integration point in cell metabolism and is of crucial clinical significance. The mechanism of how this network is regulated is the key to understanding tumor heterogeneity and overcoming the potential mechanism of tumor recurrence. Herein, we review the role of SGOC metabolism in cancer by focusing on key enzymes with tumor-promoting functions and important products with physiological significance in tumorigenesis. In addition, we introduce the ways in which cancer cells acquire and use one-carbon unit, and discuss the recently clarified role of SGOC metabolic enzymes in tumorigenesis and development, as well as their relationship with cancer immunotherapy and ferroptosis. The targeting of SGOC metabolism may be a potential therapeutic strategy to improve clinical outcomes in cancers.

[Effect of Morus alba extract sanggenon C on growth and proliferation of glioblastoma cells].

Glioblastoma is the most common primary cranial malignancy, and chemotherapy remains an important tool for its treatment. Sanggenon C(San C), a class of natural flavonoids extracted from Morus plants, is a potential antitumor herbal monomer. In this study, the effect of San C on the growth and proliferation of glioblastoma cells was examined by methyl thiazolyl tetrazolium(MTT) assay and 5-bromodeoxyuridinc(BrdU) labeling assay. The effect of San C on the tumor cell cycle was examined by flow cytometry, and the effect of San C on clone formation and self-renewal ability of tumor cells was examined by soft agar assay. Western blot and bioinformatics analysis were used to investigate the mechanism of the antitumor activity of San C. In the presence of San C, the MTT assay showed that San C significantly inhibited the growth and proliferation of tumor cells in a dose and time-dependent manner. BrdU labeling assay showed that San C significantly attenuated the DNA replication activity in the nucleus of tumor cells. Flow cytometry confirmed that San C blocked the cell cycle of tumor cells in G_0/G_1 phase. The soft agar clone formation assay revealed that San C significantly attenuated the clone formation and self-renewal ability of tumor cells. The gene set enrichment analysis(GSEA) implied that San C inhibited the tumor cell division cycle by affecting the myelocytomatosis viral oncogene(MYC) signaling pathway. Western blot assay revealed that San C inhibited the expression of cyclin through the regulation of the MYC signaling pathway by lysine demethylase 4B(KDM4B), which ultimately inhibited the growth and proliferation of glioblastoma cells and self-renewal. In conclusion, San C exhibits the potential antitumor activity by targeting the KDM4B-MYC axis to inhibit glioblastoma cell growth, proliferation, and self-renewal.

Target enzymes in serine-glycine-one-carbon metabolic pathway for cancer therapy.

Cancer cells selectively take up exogenous serine or synthesize serine via the serine synthesis pathway for conversion into intracellular glycine and one-carbon units for nucleotide biosynthesis. In this process, serine-glycine metabolism and the one-carbon cycle play vital roles, which is named serine-glycine-one-carbon metabolism (SGOC). The SGOC pathway is a metabolic network crucial for tumorigenesis with unexpected complexity and clinical importance. Accumulating evidence has demonstrated that metabolic enzymes in SGOC metabolism play key roles in tumorigenesis, metastasis and resistance to therapies. In this review, we focus on the involvement of serine and glycine in the folate-mediated one-carbon pathway during cancer progression and highlight the pathways through which cancer cells acquire and use one-carbon units. In addition, we discuss the recently elucidated effects of SGOC (folate cycle) metabolic enzymes in the occurrence and development of tumors and their links to drug resistance. Inhibitors of target enzymes in the SGOC pathway display promise as investigational new drug candidates for the treatment of tumors.

HECTD3 regulates the tumourigenesis of glioblastoma by polyubiquitinating PARP1 and activating EGFR signalling pathway.

BACKGROUND: The E3 ubiquitin ligase HECTD3 is a homologue of the E6-related protein carboxyl terminus, which plays a crucial role in biological processes and tumourigenesis. However, the functional characterisation of HECTD3 in glioblastoma is still elusive. METHODS: Determination of the functional role of HECTD3 in glioblastoma was made by a combination of HECTD3 molecular pattern analysis from human glioblastoma databases and subcutaneous and in situ injections of tumours in mice models. RESULTS: This study reports that the DOC domain of HECTD3 interacts with the DNA binding domain of PARP1, and HECTD3 mediated the K63-linked polyubiquitination of PARP1 and stabilised the latter expression. Moreover, the Cysteine (Cys) 823 (ubiquitin-binding site) mutation of HECTD3 significantly reduced PARP1 polyubiquitination and HECTD3 was involved in the recruitment of ubiquitin-related molecules to PARP1 ubiquitin-binding sites (Lysines 209 and 221, respectively). Lastly, activation of EGFR-mediated signalling pathways by HECTD3 regulates PARP1 polyubiquitination. CONCLUSION: Our results unveil the potential role of HECTD3 in glioblastoma and strongly preconise further investigation and consider HECTD3 as a promising therapeutic marker for glioblastoma treatment.

HECTD3 promotes gastric cancer progression by mediating the polyubiquitination of c-MYC.

The E3 ubiquitin ligase HECTD3 is homologous with the E6 related protein carboxyl terminus, which plays a vital role in biological modification, including immunoreactivity, drug resistance and apoptosis. Current research indicates that HECTD3 promotes the malignant proliferation of multiple tumors and increases drug tolerance. Our study primarily explored the important function and effects of HECTD3 in gastric cancer. Here, we discovered that HECTD3 is abnormally activated in gastric cancer, and the clinical prognosis database suggested that HECTD3 was strongly expressed in gastric cancer. Depletion of HECTD3 restrained the proliferative and clone abilities of cells and induced the apoptosis of gastric cancer cells. Mechanistically, our findings revealed that interaction between HECTD3 and c-MYC, and that the DOC domain of HECTD3 interacted with the CP and bHLHZ domains of c-MYC. Furthermore, we discovered that HECTD3 mediates K29-linked polyubiquitination of c-MYC. Then, our research indicated that cysteine mutation at amino acid 823 (ubiquitinase active site) of HECTD3 reduces the polyubiquitination of c-MYC. Our experimental results reveal that HECTD3 facilitates the malignant proliferation of gastric cancer by mediating K29 site-linked polyubiquitination of c-MYC. HECTD3 might become a curative marker.

Effects of Cynaroside on Cell Proliferation, Apoptosis, Migration and Invasion though the MET/AKT/mTOR Axis in Gastric Cancer.

The Chinese medicine monomer cynaroside (Cy) is a flavonoid glycoside compound that widely exists in plants and has a variety of pharmacological effects, such as its important role in the respiratory system, cardiovascular system and central nervous system. Studies have reported that Cy has varying degrees of anticancer activity in non-small cell lung cancer, cervical cancer, liver cancer, esophageal cancer and other cancers. However, there are no relevant reports about its role in gastric cancer. The MET/AKT/mTOR signaling pathway plays important roles in regulating various biological processes, including cell proliferation, apoptosis, autophagy, invasion and tumorigenesis. In this study, we confirmed that Cy can inhibit the cell growth, migration and invasion and tumorigenesis in gastric cancer. Our finding shows that Cy can block the MET/AKT/mTOR axis by decreasing the phosphorylation level of AKT, mTOR and P70S6K. Therefore, the MET/AKT/mTOR axis may be an important target for Cy. In summary, Cy has anti-cancer properties and is expected to be a potential drug for the treatment of gastric cancer.

[Anti-tumor activity of tigecycline: a review].

Tigecycline is a novel glycylcycline antibacterial drug, which shows both antibiotic function and anti-tumor activity. This review summarizes the single and combined use of tigecycline for tumor treatment and the underpinning mechanisms. As an inhibitor for mitochondrial DNA translation, tigecycline affects the proliferation, migration, and invasion of tumor cells mainly through inhibiting mitochondrial protein synthesis and inducing mitochondrial dysfunction. Although the effect of tigecycline monotherapy is controversial, the efficacy of combined use of tigecycline is satisfactory. Therefore, it is important to explore the molecular mechanisms underpinning the anti-tumor activity of tigecycline, with the aim to use it as a cheap and effective new anti-tumor drug.

Polydatin Inhibits Cell Viability, Migration, and Invasion Through Suppressing the c-Myc Expression in Human Cervical Cancer.

Polydatin, an active ingredient from the roots of Polygonum cuspidatum, is considered to have protective effects on the cardiovascular system and liver. In this study, we demonstrated that polydatin has antitumor activity against human cervical cancer. Polydatin efficiently inhibited cervical cancer cell proliferation by regulating cell cycle-related proteins including p21, p27, CDK2, CDK4, Cyclin D1, and Cyclin E1. Furthermore, polydatin suppressed cell invasion and migration by regulating epithelial-mesenchymal transition (EMT) markers, including E-cadherin, N-cadherin, Snail and Slug. The c-Myc, as a proto-oncogene, is considered to be closely associated with the proliferation and metastasis of tumor cells. After polydatin treatment, the protein expression of c-Myc showed a significant decrease. Based on these data, we overexpressed c-Myc in cervical cancer cells and observed that the overexpression of c-Myc rescued the inhibitory effect of polydatin on cell proliferation and metastasis. These results indicated that polydatin can inhibit cell proliferation and metastasis through suppressing the c-Myc expression in human cervical cancer.

[Effects of tetrandrine on proliferation, migration, and invasion of glioblastoma cells].

Glioblastoma is the most common intracranial primary malignant tumor, which leads to the poor quality of life of patients and has a high recurrence rate. Chemotherapy is a vital part in the treatment of this disease. Tetrandrine(Tet) is an active ingredient extracted from the root of the Chinese medicinal plant Stephania tetrandra, which has been proved with a wide range of pharmacological effects including anti-tumor. However, there are few studies regarding the effect of Tet on glioma. In this study, MTT and BrdU assays were employed to detect the effect of Tet on the proliferation of LN229 glioblastoma cells; flow cytometry was used to analyze the cycle distribution and apoptosis; plate cloning assay and soft agar colony formation assay were performed to study the colony formation ability of LN229 cells exposed to Tet; scratch assay and Transwell assay were conducted to detect the ability of migration and invasion; Western blot was adopted to the exploration of the molecular mechanism. The MTT and BrdU assays showed that Tet inhibited the proliferation of LN229 cells in a time-and dose-dependent manner. The plate cloning assay and soft agar colony formation assay showed that Tet weakened the colony formation of LN229 cells in vitro; cytometry assay showed that Tet blocked cells in the G_1 phase and promoted cell apoptosis; scratch and Transwell assays proved that Tet inhibited the migration and invasion of LN229 cells; Western blot results showed that Tet down-regulated the expression levels of CDK2, CDK6, cyclin D1, cyclin E1, snail, slug, vimentin, and N-cadherin, while up-regulated the level of E-cadherin. The results indicate that Tet has a certain inhibitory effect on the proliferation, migration, and invasion of LN229 glioblastoma cells, and such effect may be related to the participation of Tet in the regulation of c-Myc/p27 axis and snail signaling pathway.

The Diverse Roles of Histone Demethylase KDM4B in Normal and Cancer Development and Progression.

Histone methylation status is an important process associated with cell growth, survival, differentiation and gene expression in human diseases. As a member of the KDM4 family, KDM4B specifically targets H1.4K26, H3K9, H3K36, and H4K20, which affects both histone methylation and gene expression. Therefore, KDM4B is often regarded as a key intermediate protein in cellular pathways that plays an important role in growth and development as well as organ differentiation. However, KDM4B is broadly defined as an oncoprotein that plays key roles in processes related to tumorigenesis, including cell proliferation, cell survival, metastasis and so on. In this review, we discuss the diverse roles of KDM4B in contributing to cancer progression and normal developmental processes. Furthermore, we focus on recent studies highlighting the oncogenic functions of KDM4B in various kinds of cancers, which may be a novel therapeutic target for cancer treatment. We also provide a relatively complete report of the progress of research related to KDM4B inhibitors and discuss their potential as therapeutic agents for overcoming cancer.

NUCKS promotes cell proliferation and suppresses autophagy through the mTOR-Beclin1 pathway in gastric cancer.

BACKGROUND: Nuclear casein kinase and cyclin-dependent kinase substrate (NUCKS), a novel gene first reported in 2001, is a member of the high mobility group (HMG) family. Although very little is known regarding the biological roles of NUCKS, emerging clinical evidence suggests that the NUCKS protein can be used as a biomarker and therapeutic target in various human ailments, including several types of cancer. METHODS: We first assessed the potential correlation between NUCKS expression and gastric cancer prognosis. Then functional experiments were conducted to evaluate the effects of NUCKS in cell proliferation, cell cycle, apoptosis and autophagy. Finally, the roles of NUCKS on gastric cancer were examined in vivo. RESULTS: We found that NUCKS was overexpressed in gastric cancer patients with poor prognosis. Through manipulating NUCKS expression, it was observed to be positively associated with cell proliferation in vitro and in vivo. NUCKS knockdown could induce cell cycle arrest and apoptosis. Then further investigation indicated that NUCKS knockdown could also significantly induce a marked increase in autophagy though the mTOR-Beclin1 pathway, which could be was rescued by NUCKS restoration. Moreover, silencing Beclin1 in NUCKS knockdown cells or adding rapamycin in NUCKS-overexpressed cells also confirmed these results. CONCLUSIONS: Our findings revealed that NUCKS functions as an oncogene and an inhibitor of autophagy in gastric cancer. Thus, the downregulation or inhibition of NUCKS may be a potential therapeutic strategy for gastric cancer.

Serine-glycine-one-carbon metabolism: vulnerabilities in MYCN-amplified neuroblastoma.

In a recent study published in Cancer Research, Xia and colleagues reported that, in cancer, constituents in serine-glycine-one-carbon (SGOC) metabolism exhibit enhanced transcriptional activation and are increasingly utilised, which results in more glucose-derived carbon to serine-glycine biosynthesis. The current work identifies an MYCN-dependent metabolic vulnerability and shows a variety of associations between metabolic reprogramming and enhanced sensitivity to metabolic stress, which may lead the way to unlocking new anticancer therapies. Here, we summarised new insights into the role of SGOC metabolism in the progression of neuroblastoma (NB) with highly activated SGOC metabolism.

CDGSH Iron Sulfur Domain 2 Deficiency Inhibits Cell Proliferation and Induces Cell Differentiation of Neuroblastoma.

CDGSH iron sulfur domain 2 (CISD2) is reported to be highly expressed in several cancers, but the role of it in neuroblastoma has not been identified yet. Here, for the first time, we show that CISD2 is involved in neuroblastoma tumorigenesis and regulates neuroblastoma cell proliferation and differentiation. We found that high CISD2 expression correlated significantly with poor outcome of neuroblastoma patients, as well as advanced neuroblastoma tumor stages. Knockdown of CISD2 greatly repressed neuroblastoma cell proliferation and tumorigenesis both in vitro and in vivo. Further investigation showed that CISD2 deficiency resulted in cell cycle arrest in G1 phase and induced cell differentiation of neuroblastoma. Several Cyclins and Cyclin-Dependent Kinases (CDKs) were down-regulated by CISD2 knockdown, indicating that CISD2 probably regulates cell cycle through those genes. Together, we provide evidence that CISD2 is an indicator for neuroblastoma patients prognosis and is indispensable for neuroblastoma cell proliferation and tumorigenesis; CISD2 deficiency can induce neuroblastoma cell cycle arrest and differentiation. These findings suggest that CISD2 could work as a novel and potential therapeutic target for neuroblastoma treatment.

The Roles of Sirtuin Family Proteins in Cancer Progression.

Sirtuin family members are characterized by either mono-ADP-ribosyltransferase or deacylase activity and are linked to various cancer-related biological pathways as regulators of transcriptional progression. Sirtuins play fundamental roles in carcinogenesis and maintenance of the malignant phenotype, mainly participating in cancer cell viability, apoptosis, metastasis, and tumorigenesis. Although sirtuin family members have a high degree of homology, they may play different roles in various kinds of cancer. This review highlights their fundamental roles in tumorigenesis and cancer development and provides a critical discussion of their dual roles in cancer, namely, as tumor promoters or tumor suppressors.

Tubeimoside-1 Inhibits Glioblastoma Growth, Migration, and Invasion via Inducing Ubiquitylation of MET.

Tubeimoside-1 (TBMS1) is one of the extracts of rhizoma bolbostemmae, which has remarkable anti-cancer function in the treatment of esophagus and gastric cancer in traditional Chinese medicine. However the mechanisms of its anti-cancer function is remain unclear. In this study, we demonstrate that TBMS1 could inhibit cell growth and metastasis in glioblastoma. MET is a member of the receptor tyrosine kinase family, which amplifies frequently in various human cancers. As an important proto-oncogene, multiple inhibitors have been developed for the therapy of cancers. Here, we found TBMS1 could reduce/decrease the protein level of MET via increasing its Ubiquitination degradation. Therefore, TBMS1 is a promising compound for the treatment of glioblastoma and an inhibitor of MET.