Proteomics Identifies LUC7L3 as a Prognostic Biomarker for Hepatocellular Carcinoma.

Alternative splicing has been shown to participate in tumor progression, including hepatocellular carcinoma. The poor prognosis of patients with HCC calls for molecular classification and biomarker identification to facilitate precision medicine. We performed ssGSEA analysis to quantify the pathway activity of RNA splicing in three HCC cohorts. Kaplan-Meier and Cox methods were used for survival analysis. GO and GSEA were performed to analyze pathway enrichment. We confirmed that RNA splicing is significantly correlated with prognosis, and identified an alternative splicing-associated protein LUC7L3 as a potential HCC prognostic biomarker. Further bioinformatics analysis revealed that high LUC7L3 expression indicated a more progressive HCC subtype and worse clinical features. Cell proliferation-related pathways were enriched in HCC patients with high LUC7L3 expression. Consistently, we proved that LUC7L3 knockdown could significantly inhibit cell proliferation and suppress the activation of associated signaling pathways in vitro. In this research, the relevance between RNA splicing and HCC patient prognosis was outlined. Our newly identified biomarker LUC7L3 could provide stratification for patient survival and recurrence risk, facilitating early medical intervention before recurrence or disease progression.

Identification of RRM2 as a key ferroptosis-related gene in sepsis.

OBJECTIVE: Sepsis and sepsis-associated organ failure are devastating conditions for which there are no effective therapeutic agent. Several studies have demonstrated the significance of ferroptosis in sepsis. The study aimed to identify ferroptosis-related genes (FRGs) in sepsis, providing potential therapeutic targets. METHODS: The weighted gene co-expression network analysis (WGCNA) was utilized to screen sepsis-associated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to explore gene functions. Three machine learning methods were employed to identify sepsis-related hub genes. Survival and multivariate Cox regression analysis allowed further screening for the key gene RRM2 associated with prognosis. The immune infiltration analysis of the screened sepsis key genes was performed. Additionally, a cecum ligation and puncture (CLP)-induced mouse sepsis model was constructed to validate the expression of key gene in the sepsis. RESULTS: Six sepsis-associated differentially expressed FRGs (RRM2, RPL7A, HNRNPA1, PEBP1, MYL8B and TXNIP) were screened by WGCNA and three machine learning methods analysis. Survival analysis and multivariate Cox regression analysis showed that RRM2 was a key gene in sepsis and an independent prognostic factor associated with clinicopathological and molecular features of sepsis. Immune cell infiltration analysis demonstrated that RRM2 had a connection to various immune cells, such as CD4 T cells and neutrophils. Furthermore, animal experiment demonstrated that RRM2 was highly expressed in CLP-induced septic mice, and the use of Fer-1 significantly inhibited RRM2 expression, inhibited serum inflammatory factor TNF-α, IL-6 and IL-1ß expression, ameliorated intestinal injury and improved survival in septic mice. CONCLUSION: RRM2 plays an important role in sepsis and may contribute to sepsis through the ferroptosis pathway. This study provides potential therapeutic targets for sepsis.

EZH2 inhibition induces senescence via ERK1/2 signaling pathway in multiple myeloma.

Epigenetic modifications play an important role in cellular senescence, and enhancer of zeste homolog 2 (EZH2) is a key methyltransferase involved in epigenetic remodeling in multiple myeloma (MM) cells. We have previously demonstrated that GSK126, a specific EZH2 inhibitor, exhibits anti-MM therapeutic efficacy and safety in vivo and in vitro; however, its specific mechanism remains unclear. This study shows that GSK126 induces cellular senescence in MM, which is characterized by the accumulation of senescence-associated heterochromatin foci (SAHF) and p21, and increased senescence-associated ß galactosidase activity. Furthermore, EZH2 is inhibited in ribonucleotide reductase regulatory subunit M2 (RRM2)-overexpressing OCI-MY5 and RPMI-8226 cells. RRM2 overexpression inhibits the methyltransferase function of EZH2 and promotes its degradation through the ubiquitin-proteasome pathway, thereby inducing cellular senescence. In this senescence model, Lamin B1, a key component of the nuclear envelope and a marker of senescence, does not decrease but instead undergoes aberrant accumulation. Meanwhile, phosphorylation of extracellular signal-regulated protein kinase (ERK1/2) is significantly increased. The inhibition of ERK1/2 phosphorylation in turn partially restores Lamin B1 level and alleviates senescence. These findings suggest that EZH2 inhibition increases Lamin B1 level and induces senescence by promoting ERK1/2 phosphorylation. These data indicate that EZH2 plays an important role in MM cellular senescence and provide insights into the relationships among Lamin B1, p-ERK1/2, and cellular senescence.

Triacanthine enhances the sensitivity of colorectal cancer cells to 5-fluorouracil by regulating RRM2.

BACKGROUND: According to the literatures, triacanthine is isolated from the leaves of Gleditsia triacanthos L. and acts as an anti-hypertensive agent, also cardiotonic, antispasmodic and a respiratory analeptic. The 5-fluorouracil (5-FU) is widely used to treat the patients of colorectal cancer (CRC), but the resistance to 5-FU treatment restricts the therapeutic efficacy of CRC patients. PURPOSE: This study aims to explore a novel therapeutics regimen overcoming CRC resistance to 5-FU. METHODS: The cell proliferation of CRC cells was determined by SRB and colony formation assay. Transwell and wound-healing assay were applied to explore the potential metastatic abilities of CRC cells. qRT-PCR and Western blot were performed to evaluate the level of indicated mRNAs and proteins respectively. Xenograft assay was used to explore the anti-CRC effect of triacanthine. RESULTS: Triacanthine statistically restrained CRC proliferation both in vitro and in vivo. Triacanthine induced cell cycle G1/G0 phase arrest in CRC cells. Meanwhile, triacanthine also inhibited the migrative and invasive abilities of CRC cells. A Venn diagram was generated showing that O-6-Methylguanine-DNA Methyltransferase (MGMT) might be a molecular target of triacanthine in treating CRC. Furthermore, triacanthine plus 5-FU significantly suppressed the cell proliferation of CRC cells compared with single agent treatment alone, and highly synergistic anti-cancer effects were scored when 5-FU was combined with triacanthine in CRC cells. In addition, triacanthine sensitized the anti-cancer activity of 5-FU via regulating Ribonucleotide Reductase Regulatory Subunit M2 (RRM2). MGMT or RRM2 might be novel biomarkers for evaluating the therapeutical efficiency of 5-FU in CRC patients. CONCLUSION: We firstly demonstrated triacanthine suppressed cell proliferation and metastasis abilities and found the novel molecular targets of triacanthine in CRC cells. This is the first study to evaluate the anti-cancer efficiency of triacanthine plus 5-FU. Our study has revealed triacanthine as a pertinent sensitizer to 5-FU, and provided novel strategies for predicting outcomes and reversing resistance of 5-FU therapy.

RRM2 promotes the proliferation of chicken myoblasts, inhibits their differentiation and muscle regeneration.

During myogenesis and regeneration, the proliferation and differentiation of myoblasts play key regulatory roles and may be regulated by many genes. In this study, we analyzed the transcriptomic data of chicken primary myoblasts at different periods of proliferation and differentiation with protein‒protein interaction network, and the results indicated that there was an interaction between cyclin-dependent kinase 1 (CDK1) and ribonucleotide reductase regulatory subunit M2 (RRM2). Previous studies in mammals have a role for RRM2 in skeletal muscle development as well as cell growth, but the role of RRM2 in chicken is unclear. In this study, we investigated the effects of RRM2 on skeletal muscle development and regeneration in chickens in vitro and in vivo. The interaction between RRM2 and CDK1 was initially identified by co-immunoprecipitation and mass spectrometry. Through a dual luciferase reporter assay and quantitative real-time PCR, we identified the core promoter region of RRM2, which is regulated by the SP1 transcription factor. In this study, through cell counting kit-8 assays, 5-ethynyl-2'-deoxyuridine incorporation assays, flow cytometry, immunofluorescence staining, and Western blot analysis, we demonstrated that RRM2 promoted the proliferation and inhibited the differentiation of myoblasts. In vivo studies showed that RRM2 reduced the diameter of muscle fibers and slowed skeletal muscle regeneration. In conclusion, these data provide preliminary insights into the biological functions of RRM2 in chicken muscle development and skeletal muscle regeneration.

Targeting the Cell Cycle, RRM2 and NF-κB for the Treatment of Breast Cancers.

A hallmark of cancer is the dysregulation of the cell cycle. The CDK4/6 inhibitor palbociclib is approved for treating advanced estrogen-receptor-positive breast cancer, but its success is limited by the development of acquired resistance owing to long-term therapy despite promising clinical outcomes. This situation necessitates the development of potential combination strategies. Here, we report that didox, an inhibitor of ribonucleotide reductase in combination with palbociclib, can overcome palbociclib resistance in ER-positive and ER-negative breast cancers. This study shows didox downregulates an element of the cell cycle checkpoint, cyclin D1, accompanied by a reduction in NF-κB activity in vitro and tumor growth inhibition of palbociclib-resistant ER positive breast cancer tumor growth in vivo. Furthermore, didox induces cell cycle arrest at G1 as well as reduces ROS generated by on-target effects of palbociclib on the cell cycle. Our current study also reports that the CCND1 and RRM2 upregulation associated with palbociclib-resistant breast cancers decreases upon ribonucleotide reductase inhibition. Our data present a novel and promising biomarker-driven combination therapeutic approach for the treatment of ER-positive and ER-negative breast cancers that involves the inhibition of the CDK4/6-cyclinD1/pRb cell cycle axis that merits further clinical investigation in human models.

Identification and prognostic analysis of metabolic genes associated with TP53 mutation in multiple myeloma.

BACKGROUND: TP53 gene mutation is crucial in determining the prognosis of Multiple Myeloma (MM) patients. Understanding metabolic genes linked to TP53 mutation is vital for developing targeted therapies for these patients. METHOD: We analyzed The Cancer Genome Atlas (TCGA) dataset to identify genes related to TP53 mutation and metabolism. Using univariate Cox regression and protein-protein interaction (PPI) analysis, we identified key genes. We categorized patients into high and low metabolism groups via non-negative matrix factorization (NMF) clustering, which led to the discovery of relevant differential genes. Integrating these with genes from the Gene Expression Omnibus (GEO) datasets and PPI interactions, we pinpointed crucial metabolic genes associated with TP53 mutation in MM. Additionally, we conducted prognostic analyses involving survival curves and receiver operating characteristic (ROC) charts. RESULTS: Our study reveals that the metabolic gene ribonucleotide reductase M2 (RRM2), linked to TP53 mutation, correlates positively with the International Staging System (ISS) stage in MM patients and is an independent prognostic risk factor. In the TCGA dataset, among the 767 patients, the 35 MM patients with TP53 mutation generally had poor survival outcomes. Specifically, the patients with both TP53 mutation and high RRM2 expression had a 2-year survival rate of only 38.87%, whereas those with normal TP53 function and low RRM2 expression had a 2-year survival rate of 86.31% (p < 0.001). CONCLUSION: RRM2 significantly impacts MM prognosis and is associated with TP53 mutation, presenting itself as a potential therapeutic target and prognostic marker for MM.

GINS2 promotes the progression of human HNSCC by altering RRM2 expression.

INTRODUCTION: GINS2 exerts a carcinogenic effect in multiple human malignancies, while it is still unclear that the potential roles and underlying mechanisms of GINS2 in HNSCC. METHODS: TCGA database was used to screen out genes with significant differences in expression in HNSCC. Immunohistochemistry and qRT-PCR were used to measure the expression of GINS2 in HNSCC tissues and cells. GINS2 was detected by qRT-PCR or western blot after knockdown or overexpression. Celigo cell counting, MTT, colony formation, and flow cytometric assay were used to check the ability of proliferation and apoptosis. Bioinformatics and microarray were used to screen out the downstream genes of GINS2. RESULTS: GINS2 in HNSCC tissues and cells was up-regulated, which was correlated with poor prognosis. GINS2 gene expression was successfully inhibited and overexpressed in HNSCC cells. Knockdown of GINS2 could inhibit proliferation and increase apoptosis of cells. Meanwhile, overexpression of GINS2 could enhance cell proliferation and colony formation. Knockdown of RRM2 may inhibit HNSCC cell proliferation, while overexpression of RRM2 rescued the effect of reducing GINS2 expression. CONCLUSION: Our study reported the role of GINS2 in HNSCC for the first time. The results demonstrated that in HNSCC cells, GINS2 promoted proliferation and inhibited apoptosis via altering RRM2 expression. Therefore, GINS2 might play a carcinogen in HNSCC, and become a specific promising therapeutic target.

Characterization of risks and pathogenesis of respiratory diseases caused by rural atmospheric PM2.5.

Forty-six percent of the world's population resides in rural areas, the majority of whom belong to vulnerable groups. They mainly use cheap solid fuels for cooking and heating, which release a large amount of PM2.5 and cause adverse effects to human health. PM2.5 exhibits urban-rural differences in its health risk to the respiratory system. However, the majority of research on this issue has focused on respiratory diseases induced by atmospheric PM2.5 in urban areas, while rural areas have been ignored for a long time, especially the pathogenesis of respiratory diseases. This is not helpful for promoting environmental equity to aid vulnerable groups under PM2.5 pollution. Thus, this study focuses on rural atmospheric PM2.5 in terms of its chemical components, toxicological effects, respiratory disease types, and pathogenesis, represented by PM2.5 from rural areas in the Sichuan Basin, China (Rural SC-PM2.5). In this study, organic carbon is the most significant component of Rural SC-PM2.5. Rural SC-PM2.5 significantly induces cytotoxicity, oxidative stress, and inflammatory response. Based on multiomics, bioinformatics, and molecular biology, Rural SC-PM2.5 inhibits ribonucleotide reductase regulatory subunit M2 (RRM2) to disrupt the cell cycle, impede DNA replication, and ultimately inhibit lung cell proliferation. Furthermore, this study supplements and supports the epidemic investigation. Through an analysis of the transcriptome and human disease database, it is found that Rural SC-PM2.5 may mainly involve pulmonary hypertension, sarcoidosis, and interstitial lung diseases; in particular, congenital diseases may be ignored by epidemiological surveys in rural areas, including tracheoesophageal fistula, submucous cleft of the hard palate, and congenital hypoplasia of the lung. This study contributes to a greater scientific understanding of the health risks posed by rural PM2.5, elucidates the pathogenesis of respiratory diseases, clarifies the types of respiratory diseases, and promotes environmental equity.

Celastrol induces ferroptosis by suppressing RRM2 in hepatocellular carcinoma.

Introduction and Objectives: Ferroptosis is a novel form of cell death driven by iron dependence and lipid peroxidation, presenting a promising potential as an innovative strategy for cancer treatment. Celastrol (Cel) is particularly effective in inducing ferroptosis, but its molecular mechanism remains unclear. The study aims to elucidate the potential mechanism through both in vitro and in vivo experiments. Materials and methods: CCK-8 assay, Western blot analysis and measurements of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) were performed to investigate how Cel inhibits the proliferation of hepatocellular carcinoma (HCC) cells via the ferroptosis mechanism. Bioinformatics analysis based on the TCGA-LIHC and FerrDb databases was performed to identify the target gene RRM2, and molecular docking-simulated binding between RRM2 and Cel. The role of RRM2 in the effects of Cel was determined through lentiviral transfection, Transwell assays, and in vivo experiments. Results: Cel inhibited HCC cell proliferation via the ferroptosis pathway. Inhibition RRM2 significantly reduces mTOR protein phosphorylation, while overexpressing RRM2 can attenuate theeffects of Cel on the proliferation, migration, invasion, and ferroptosis induction of HCC cells. The result of in vivo experiments in nude mice demonstrated that Cel inhibited tumor growth without adversely affecting liver and kidney function indicators. Immunohistochemistry and Western blot analyses revealed that Cel activated the key proteins in the ferroptosis pathway and affected crucial indicators such as malondialdehyde (MDA) and glutathione (GSH). Conclusion: In this study, we clarifiy the molecular mechanism of Cel, thus broadening its clinical applications for treating various cancer types, including liver cancer.

Higher concentration of P7C3 than required for neuroprotection suppresses renal cell carcinoma growth and metastasis.

Background: P7C3 is a novel compound that has been widely applied in neurodegenerative diseases and nerve injury repair. Here, we show that higher concentrations of P7C3 than are required for in vivo neuroprotection have the novel function of suppressing renal cell carcinoma (RCC) proliferation and metastasis. Methods: Colony formation, CCK-8 and EdU assay were applied to evaluate RCC cell proliferation. Wound healing and transwell assay were used to measure RCC cell migration and invasion. Flow cytometry assay was employed to detect RCC cell apoptosis and cell cycle. qRT-PCR assay was carried out to measure ribonucleotide reductase subunit M2 (RRM2) mRNA expression level, while western blot assay was utilized to detect the expression level of target proteins. RCC cell growth in vivo was determined by xenografts in mice. Results: We observed that high concentrations of P7C3 could restrain the proliferation and metastasis of RCC cells and promote cell apoptosis. Mechanistically, this new effect of higher dose of P7C3 was associated with reduced expression of RRM2, and the beneficial efficacy of P7C3 in RCC was blocked when suppression of RRM2 was prevented. When RRM2 suppression was permitted, the cGAS-STING pathway was activated by virtue of RRM2/Bcl-2/Bax signaling. Lastly, intraperitoneal injection of this high level of P7C3 in mice potently inhibited tumor growth. Conclusion: In conclusion, we show here that P7C3 that exerts an anti-cancer effect in RCC. Our study indicated that P7C3 might act as a novel drug for RCC in the future. The regulatory signal pathway RRM2/Bcl-2/BAX/cGAS-STING might present novel insight to the potential mechanism of RCC development.

p53 deficiency mediates cisplatin resistance by upregulating RRM2 and crotonylation of RRM2K283 through the downregulation of SIRT7.

p53 deficiency plays a crucial role in chemotherapy resistance through various biological events, including posttranslational modifications (PTMs). Recently, lysine crotonylation (Kcr) has been shown to play a vital role in cancer progression. However, the global p53-regulated crotonylome and the function of these altered Kcr proteins after p53 deficiency remain unclear. In this study, we used a SILAC-based quantitative crotonylome to identify 3,520 Kcr in 1924 crotonylated proteins in response to p53 knockout. We found that increased crotonylation of RRM2 at K283 (RRM2K283Cr) in the presence of p53 deficiency promoted HCT116 cell resistance to cisplatin. We discovered that SIRT7 could be the decrotonylase of RRM2 and was downregulated after p53 knockout, resulting in increased RRM2K283Cr. Mechanistically, p53 deficiency inhibited cell apoptosis by upregulating RRM2 protein expression and RRM2K283Cr-mediated cleaved-PARP1 and cleaved-caspase3 expression, and SIRT7 was downregulated to upregulate crotonylation of RRM2 upon p53 deficiency. In conclusion, our results indicated that p53 deficiency plays a malignant role in colon cancer resistance to cisplatin therapy by regulating RRM2 protein and RRM2K283Cr expression. Our findings provide a novel therapeutic target against p53-deficient cancer.

RRM2 Is a CTNNB1 Transport Regulator Promoting Colon Cancer Progression.

BACKGROUND/AIM: The cytoplasmic retention and stabilization of CTNNB1 (ß-catenin) in response to Wnt is well documented in playing a role in tumor growth. Here, through the utilization of a multiplex siRNA library screening strategy, we investigated the modulation of CTNNB1 function in tumor cell progression by ribonucleoside-diphosphate reductase subunit M2 (RRM2). MATERIALS AND METHODS: We conducted a multiplex siRNA screening assay to identify targets involved in CTNNB1 nuclear translocation. In order to examine the effect of inhibition of RRM2, selected from the siRNA screening results, we performed RRM2 knockdown and assayed for colon cancer cell viability, sphere formation assay, and invasion assay. The interaction of RRM2 with CTNNB1 and its impact on oncogenesis was examined using immunoprecipitation, immunoblotting, immunocytochemistry, and RT-qPCR. RESULTS: After a series of screening and filtration steps, we identified 26 genes that were potentially involved in CTNNB1 nuclear translocation. All candidate genes were validated in various cell lines. The results revealed that siRNA-mediated knockdown of RRM2 reduces the nuclear translocation of CTNNB1. This reduction was accompanied by a decrease in cell count, resulting in a suppressive effect on tumor cell growth. CONCLUSION: High throughput siRNA screening is an attractive strategy for identifying gene functions in cancers and the interaction between RRM2 and CTNNB1 is an attractive drug target for regulating RRM2-CTNNB1-related pathways in cancers.

Auranofin and reactive oxygen species inhibit protein synthesis and regulate the level of the PLK1 protein in Ewing sarcoma cells.

Novel therapeutic approaches are needed for the treatment of Ewing sarcoma tumors. We previously identified that Ewing sarcoma cell lines are sensitive to drugs that inhibit protein translation. However, translational and therapeutic approaches to inhibit protein synthesis in tumors are limited. In this work, we identified that reactive oxygen species, which are generated by a wide range of chemotherapy and other drugs, inhibit protein synthesis and reduce the level of critical proteins that support tumorigenesis in Ewing sarcoma cells. In particular, we identified that both hydrogen peroxide and auranofin, an inhibitor of thioredoxin reductase and regulator of oxidative stress and reactive oxygen species, activate the repressor of protein translation 4E-BP1 and reduce the levels of the oncogenic proteins RRM2 and PLK1 in Ewing and other sarcoma cell lines. These results provide novel insight into the mechanism of how ROS-inducing drugs target cancer cells via inhibition of protein translation and identify a mechanistic link between ROS and the DNA replication (RRM2) and cell cycle regulatory (PLK1) pathways.

Ribonucleotide reductase inhibition improves the symptoms of a Caenorhabditis elegans model of Alzheimer's disease.

Alzheimer's disease is the main cause of aging-associated dementia, for which there is no effective treatment. In this work, we reanalyze the information of a previous genome wide association study, using a new pipeline design to identify novel potential drugs. With this approach, ribonucleoside-diphosphate reductase gene (RRM2B) emerged as a candidate target and its inhibitor, 2', 2'-difluoro 2'deoxycytidine (gemcitabine), as a potential pharmaceutical drug against Alzheimer's disease. We functionally verified the effect of inhibiting the RRM2B homolog, rnr-2, in an Alzheimer's model of Caenorhabditis elegans, which accumulates human Aß1-42 peptide to an irreversible paralysis. RNA interference against rnr-2 and also treatment with 200 ng/ml of gemcitabine, showed an improvement of the phenotype. Gemcitabine treatment increased the intracellular ATP level 3.03 times, which may point to its mechanism of action. Gemcitabine has been extensively used in humans for cancer treatment but at higher concentrations. The 200 ng/ml concentration did not exert a significant effect over cell cycle, or affected cell viability when assayed in the microglia N13 cell line. Thus, the inhibitory drug of the RRM2B activity could be of potential use to treat Alzheimer's disease and particularly gemcitabine might be considered as a promising candidate to be repurposed for its treatment.

The mechano-chemical circuit in fibroblasts and dendritic cells drives basal cell proliferation in psoriasis.

Psoriasis is an intractable immune-mediated disorder that disrupts the skin barrier. While studies have dissected the mechanism by which immune cells directly regulate epidermal cell proliferation, the involvement of dermal fibroblasts in the progression of psoriasis remains unclear. Here, we identified that signals from dendritic cells (DCs) that migrate to the dermal-epidermal junction region enhance dermal stiffness by increasing extracellular matrix (ECM) expression, which further promotes basal epidermal cell hyperproliferation. We analyzed cell-cell interactions and observed stronger interactions between DCs and fibroblasts than between DCs and epidermal cells. Using single-cell RNA (scRNA) sequencing, spatial transcriptomics, immunostaining, and stiffness measurement, we found that DC-secreted LGALS9 can be received by CD44+ dermal fibroblasts, leading to increased ECM expression that creates a stiffer dermal environment. By employing mouse psoriasis and skin organoid models, we discovered a mechano-chemical signaling pathway that originates from DCs, extends to dermal fibroblasts, and ultimately enhances basal cell proliferation in psoriatic skin.

Case Report: A novel RRM2B variant in a Chinese infant with mitochondrial DNA depletion syndrome and collective analyses of RRM2B variants for disease etiology.

Background: There are few reports of infantile mitochondrial DNA depletion syndrome (MDDS) caused by variants in RRM2B and the correlation between genotype and phenotype has rarely been analyzed in detail. This study investigated an infantile patient with MDDS, from clinical characteristics to genetic causes. Methods: Routine physical examinations, laboratory assays, which included gas chromatography-mass spectrometry of blood and urine, and MRI scans were performed to obtain an exact diagnosis. Whole-exome sequencing was used to pinpoint the abnormal gene and bioinformatic analyses were performed on the identified variant. Results: The case presented with progressive neurologic deterioration, failure to thrive, respiratory distress and lactic acidosis. Sequencing revealed that the patient had a homozygous novel missense variant, c.155T>C (p.Ile52Thr), in exon 2 of the RRM2B gene. Multiple lines of bioinformatic evidence suggested that this was a likely detrimental variant. In addition, reported RRM2B variants were compiled from the relevant literature to analyze disease etiology. We found a distinctive distribution of genotypes across disease manifestations of different severity. Pathogenic alleles of RRM2B were significantly enriched in MDDS cases. Conclusion: The novel variant is a likely genetic cause of MDDS. It expands our understanding of the pathogenic variant spectrum and the contribution of the RRM2B gene to the disease spectrum of MDDS.

Significance of Ribonucleoside-diphosphate Reductase Subunit M2 in Lung Adenocarcinoma.

INTRODUCTION: The Ribonucleoside-diphosphate Reductase subunit M2 (RRM2) is known to be overexpressed in various cancers, though its specific functional implications remain unclear. This aims to elucidate the role of RRM2 in the progression of Lung Adenocarcinoma (LUAD) by exploring its involvement and potential impact. METHODS: RRM2 data were sourced from multiple databases to assess its diagnostic and prognostic significance in LUAD. We evaluated the association between RRM2 expression and immune cell infiltration, analyzed its function, and explored the effects of modulating RRM2 expression on LUAD cell characteristics through laboratory experiments. RESULTS: RRM2 was significantly upregulated in LUAD tissues and cells compared to normal counterparts (p<0.05), with rare genetic alterations noted (approximately 2%). This overexpression clearly distinguished LUAD from normal tissue (area under the curve (AUC): 0.963, 95% confidence intervals (CI): 0.946-0.981). Elevated RRM2 expression was significantly associated with adverse clinicopathological characteristics and poor prognosis in LUAD patients. Furthermore, a positive association was observed between RRM2 expression and immune cell infiltration. Pathway analysis revealed a critical connection between RRM2 and the cell cycle signaling pathway within LUAD. Targeting RRM2 inhibition effectively suppressed LUAD cell proliferation, migration, and invasion while promoting apoptosis. This intervention also modified the expression of several crucial proteins, including the downregulation of CDC25A, CDC25C, RAD1, Bcl-2, and PPM1D and the upregulation of TP53 and Bax (p < 0.05). CONCLUSION: Our findings highlight the potential utility of RRM2 expression as a biomarker for diagnosing and predicting prognosis in LUAD, shedding new light on the role of RRM2 in this malignancy.

RRM2 promotes tumor progression by interfering with G2/M cycle of prostate cancer cells / 现代泌尿外科杂志

【Objective】 To investigate the role of RRM2 in prostate cancer and the mechanism. 【Methods】 The data of prostate cancer expression profile were downloaded from The Cancer Genome Atlas (TCGA). The correlation between RRM2 expression and clinicopathological features and prognosis of prostate cancer was analyzed. The protein expressions of RRM2 in 55 cases of prostate cancer and 38 benign tissues were determined with immunohistochemistry (IHC). The effects of RRM2 on the biological process of prostate cancer were assessed with bioinformatic analysis. The biological process of RRM2 affecting the progression of prostate cancer was verified with Western blot and flow cytometry. 【Results】 RRM2 was highly expressed in prostate cancer, and the expression was positively correlated with the clinical stage, pathological grade and metastasis of prostate cancer (P<0.05). Higher RRM2 expression predicted poorer survival. RRM2 co-expression positively correlated genes were involved in cell cycle pathways, pyrimidine nucleotide metabolism, and biological processes such as RNA transport. Cell cycle pathways were significantly enriched. RRM2 was highly correlated with CDK1 and PCNA molecules. RRM2 knockdown reduced the protein expressions of CDK1 and PCNA in DU145 and LNCap cell lines, which were arrested in the G2/M phase. 【Conclusion】 RRM2 promotes tumor progression by interfering with G2/M cycle of prostate cancer cells.

Effect of silencing human RRM 2 by specific siRNA on the biological behavior of human osteosarcoma cell / 中国基层医药

Objective To investigate the effect of small interference RNA(siRNA) targeting RRM2 on the biological behavior of human osteosarcoma cell line Saos-2 and the molecular mechanisms.Methods RRM2 expression was knocked down in human osteosarcama cell line Saos-2 by RRM2 siRNA.The expression of RRM2 mRNA and protein was determined in human osteosarcoma cell line Saos-2 and human osteoblast-like cell line hFOB1.19 by real time-PCR and Western blot.The cell proliferation was detected by CCK-8.The migration was observed by using transwell system.The apoptotic rate was observed by ELISA.The expression of CyclinD1 and Bcl-2 proteins were detected by Western blot.Results The expression of RRM2 mRNA and protein was higher in Saos-2 than in hFOB1.19.siRRM2 could down-regulate the expression of RRM2 in Saos-2 cells in a time-and concentration-dependent manner.CCK-8 assay showed that si-RRM2 could inhibit the proliferation ability of Saos-2 cells in a time-and concentrationdependent manner,but had no effect on the proliferation of hFOB1.19 cells.Transwell assay indicated that si-RRM2 could inhibit the migration of Saos-2 cells.si-RRM2 combined with adriamycin could increase the apoptosis of Saos-2 cells.Western blot showed that the expression of Cyclin D1 and Bcl-2 were decreased by silencing RRM2.Condusion RRM2 overexpression maybe associate with the osteosarcoma cells proliferation and migration and suppression of its function is a potential therapeutic strategy in osteosarcoma.