Identifying potential targets for preventing cancer progression through the PLA2G1B recombinant protein using bioinformatics and machine learning methods.

Lung cancer is the deadliest and most aggressive malignancy in the world. Preventing cancer is crucial. Therefore, the new molecular targets have laid the foundation for molecular diagnosis and targeted therapy of lung cancer. PLA2G1B plays a key role in lipid metabolism and inflammation. PLA2G1B has selective substrate specificity. In this paper, the recombinant protein molecular structure of PLA2G1B was studied and novel therapeutic interventions were designed to disrupt PLA2G1B activity and impede tumor growth by targeting specific regions or residues in its structure. Construct protein-protein interaction networks and core genes using R's "STRING" program. LASSO, SVM-RFE and RF algorithms identified important genes associated with lung cancer. 282 deg were identified. Enrichment analysis showed that these genes were mainly related to adhesion and neuroactive ligand-receptor interaction pathways. PLA2G1B was subsequently identified as developing a preventative feature. GSEA showed that PLA2G1B is closely related to α-linolenic acid metabolism. Through the analysis of LASSO, SVM-RFE and RF algorithms, we found that PLA2G1B gene may be a preventive gene for lung cancer.

The ARK2N-CK2 complex initiates transcription-coupled repair through enhancing the interaction of CSB with lesion-stalled RNAPII.

Transcription is extremely important for cellular processes but can be hindered by RNA polymerase II (RNAPII) pausing and stalling. Cockayne syndrome protein B (CSB) promotes the progression of paused RNAPII or initiates transcription-coupled nucleotide excision repair (TC-NER) to remove stalled RNAPII. However, the specific mechanism by which CSB initiates TC-NER upon damage remains unclear. In this study, we identified the indispensable role of the ARK2N-CK2 complex in the CSB-mediated initiation of TC-NER. The ARK2N-CK2 complex is recruited to damage sites through CSB and then phosphorylates CSB. Phosphorylation of CSB enhances its binding to stalled RNAPII, prolonging the association of CSB with chromatin and promoting CSA-mediated ubiquitination of stalled RNAPII. Consistent with this finding, Ark2n-/- mice exhibit a phenotype resembling Cockayne syndrome. These findings shed light on the pivotal role of the ARK2N-CK2 complex in governing the fate of RNAPII through CSB, bridging a critical gap necessary for initiating TC-NER.

PP2A inhibition causes synthetic lethality in BRCA2-mutated prostate cancer models via spindle assembly checkpoint reactivation.

Mutations in the BRCA2 tumor suppressor gene have been associated with an increased risk of developing prostate cancer. One of the paradoxes concerning BRCA2 is the fact that its inactivation affects genetic stability and is deleterious for cellular and organismal survival, while BRCA2-mutated cancer cells adapt to this detriment and malignantly proliferate. Therapeutic strategies for tumors arising from BRCA2 mutations may be discovered by understanding these adaptive mechanisms. In this study, we conducted forward genetic synthetic viability screenings in Caenorhabditis elegans brc-2 (Cebrc-2) mutants and found that Ceubxn-2 inactivation rescued the viability of Cebrc-2 mutants. Moreover, loss of NSFL1C, the mammalian ortholog of CeUBXN-2, suppressed the spindle assembly checkpoint (SAC) activation and promoted the survival of BRCA2-deficient cells. Mechanistically, NSFL1C recruited USP9X to inhibit the polyubiquitination of AURKB and reduce the removal of AURKB from the centromeres by VCP, which is essential for SAC activation. SAC inactivation is common in BRCA2-deficient prostate cancer patients, but PP2A inhibitors could reactivate the SAC and achieve BRCA2-deficient prostate tumor synthetic lethality. Our research reveals the survival adaptation mechanism of BRCA2-deficient prostate tumor cells and provides different angles for exploring synthetic lethal inhibitors in addition to targeting DNA damage repair pathways.

MBD1 protects replication fork stability by recruiting PARP1 and controlling transcription-replication conflicts.

The replication-stress response is essential to ensure the faithful transmission of genetic information to daughter cells. Although several stress-resolution pathways have been identified to deal with replication stress, the precise regulatory mechanisms for replication fork stability are not fully understood. Our study identified Methyl-CpG Binding Domain 1 (MBD1) as essential for the maintaining genomic stability and protecting stalled replication forks in mammalian cells. Depletion of MBD1 increases DNA lesions and sensitivity to replication stress. Mechanistically, we found that loss of MBD1 leads to the dissociation of Poly(ADP-ribose) polymerase 1 (PARP1) from the replication fork, potentially accelerating fork progression and resulting in higher levels of transcription-replication conflicts (T-R conflicts). Using a proximity ligation assay combined with 5-ethynyl-2'-deoxyuridine, we revealed that the MBD1 and PARP1 proteins were recruited to stalled forks under hydroxyurea (HU) treatment. In addition, our study showed that the level of R-loops also increased in MBD1-delated cells. Without MBD1, stalled replication forks resulting from T-R conflicts were primarily degraded by the DNA2 nuclease. Our findings shed light on a new aspect of MBD1 in maintaining genome stability and providing insights into the mechanisms underlying replication stress response.

The landscape of hervRNAs transcribed from human endogenous retroviruses across human body sites.

BACKGROUND: Human endogenous retroviruses (HERVs), the remnants of ancient retroviruses, account for 8% of the human genome, but most have lost their transcriptional abilities under physiological conditions. However, mounting evidence shows that several expressed HERVs do exert biological functions. Here, we systematically characterize physiologically expressed HERVs and examine whether they may give insight into the molecular fundamentals of human development and disease. RESULTS: We systematically identify 13,889 expressed HERVs across normal body sites and demonstrate that they are expressed in body site-specific patterns and also by sex, ethnicity, and age. Analyzing cis-ERV-related quantitative trait loci, we find that 5435 hervRNAs are regulated by genetic variants. Combining this with a genome-wide association study, we elucidate that the dysregulation of expressed HERVs might be associated with various complex diseases, particularly neurodegenerative and psychiatric diseases. We further find that physiologically activated hervRNAs are associated with histone modifications rather than DNA demethylation. CONCLUSIONS: Our results present a locus-specific landscape of physiologically expressed hervRNAs, which represent a hidden layer of genetic architecture in development and disease.

Suppression of DDX39B sensitizes ovarian cancer cells to DNA-damaging chemotherapeutic agents via destabilizing BRCA1 mRNA.

Multiple RNA processing events including transcription, mRNA splicing, and export are delicately coordinated by the TREX complex. As one of the essential subunits, DDX39B couples the splicing and export machineries by recruiting ALYREF onto mRNA. In this study, we further explore the functions of DDX39B in handling damaged DNA, and unexpectedly find that DDX39B facilitates DNA repair by homologous recombination through upregulating BRCA1. Specifically, DDX39B binds to and stabilizes BRCA1 mRNA. DDX39B ensures ssDNA formation and RAD51 accumulation at DSB sites by maintaining BRCA1 levels. Without DDX39B being present, ovarian cancer cells exhibit hypersensitivity to DNA-damaging chemotherapeutic agents like platinum or PARPi. Moreover, DDX39B-deficient mice show embryonic lethality or developmental retardation, highly reminiscent of those lacking BRCA1. High DDX39B expression is correlated with worse survival in ovarian cancer patients. Thus, DDX39B suppression represents a rational approach for enhancing the efficacy of chemotherapy in BRCA1-proficient ovarian cancers.

LC8/DYNLL1 is a 53BP1 effector and regulates checkpoint activation.

The tumor suppressor protein 53BP1 plays key roles in response to DNA double-strand breaks (DSBs) by serving as a master scaffold at the damaged chromatin. Current evidence indicates that 53BP1 assembles a cohort of DNA damage response (DDR) factors to distinctly execute its repertoire of DSB responses, including checkpoint activation and non-homologous end joining (NHEJ) repair. Here, we have uncovered LC8 (a.k.a. DYNLL1) as an important 53BP1 effector. We found that LC8 accumulates at laser-induced DNA damage tracks in a 53BP1-dependent manner and requires the canonical H2AX-MDC1-RNF8-RNF168 signal transduction cascade. Accordingly, genetic inactivation of LC8 or its interaction with 53BP1 resulted in checkpoint defects. Importantly, loss of LC8 alleviated the hypersensitivity of BRCA1-depleted cells to ionizing radiation and PARP inhibition, highlighting the 53BP1-LC8 module in counteracting BRCA1-dependent functions in the DDR. Together, these data establish LC8 as an important mediator of a subset of 53BP1-dependent DSB responses.

Investigation of differentially-expressed microRNAs and genes in cervical cancer using an integrated bioinformatics analysis.

Cervical cancer is one of the most common types of cancer among women worldwide. In order to identify the microRNAs (miRNAs/miRs) and mRNAs associated with the carcinogenesis of cervical cancer, and to investigate the molecular mechanisms of cervical cancer, an miRNA microarray, GSE30656, and 3 mRNA microarrays, GSE63514, GSE39001 and GSE9750, for cervical cancer were retrieved from Gene Expression Omnibus. These datasets were analyzed in order to obtain differentially-expressed genes (DEGs) and miRNAs using the GEO2R tool. Gene Ontology (GO) and pathway enrichment analysis for DEGs were performed using the Database for Annotation, Visualization and Integrated Discovery. Protein-protein interaction (PPI) analysis for DEGs was conducted using The Search Tool for the Retrieval of Interacting Genes software and visualized using Cytoscape, followed by hub gene identification, and biological process and pathway enrichment analysis of the module selected from the PPI network using the Molecular Complex Detection plugin. In addition, miRecords was applied to predict the targets of differentially-expressed miRNAs. A total of 44 DEGs and 15 differentially-expressed miRNAs were identified. These DEGs were mainly enriched in GO terms associated with the cell cycle. In the PPI network, cyclin-dependent kinase 1, topoisomerase DNA IIα, aurora kinase A (AURKA) and minichromosome maintenance complex component 2 (MCM2) had higher degrees of connectivity. A significant module was detected from the PPI network. AURKA, MCM2 and kinesin family member 20A exhibited higher degrees in this module, while the genes in the module were mainly involved in the cell cycle and the DNA replication pathway. In addition, estrogen receptor 1 was predicted as the potential target of 13 miRNAs. A total of 10 DEGs were identified as potential targets of miR-203. In conclusion, the results indicated that microarray dataset analysis may provide a useful method for the identification of key genes and patterns to successfully identify determinants of the carcinogenesis of cervical cancer. The functional studies of candidate genes and miRNAs from these databases may lead to an increased understanding of the development of cervical cancer.

Identification of candidate biomarkers and analysis of prognostic values in ovarian cancer by integrated bioinformatics analysis.

Ovarian cancer is the first leading cause of mortality in gynecological malignancies. To identify key genes and microRNAs in ovarian cancer, mRNA microarray dataset GSE36668, GSE18520, GSE14407 and microRNA dataset GSE47841 were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and microRNAs (DEMs) were obtained using GEO2R. Functional and pathway enrichment analysis were performed for DEGs using DAVID database. Protein-protein interaction (PPI) network was established by STRING and visualized by Cytoscape. Following, overall survival (OS) analysis of hub genes was performed by the Kaplan-Meier plotter online tool. Module analysis of the PPI network was performed using MCODE. Moreover, miRecords was applied to predict the targets of the DEMs. A total of 345 DEGs were obtained, which were mainly enriched in the terms related to cell cycle, mitosis, and ovulation cycle process. A PPI network was constructed, consisting of 141 nodes and 296 edges. Sixteen genes had high degrees in the network. High expression of four genes of the 16 genes was associated with worse OS of patients with ovarian cancer, including CCNB1, CENPF, KIF11, and ZWINT. A significant module was detected from the PPI network. The enriched functions and pathways included cell cycle, nuclear division, and oocyte meiosis. Additionally, a total of 36 DEMs were identified. The expression of KIF11 was negatively correlated with that of has-miR-424 and has-miR-381, and it was also the potential target of two microRNAs. In conclusion, these results identified key genes, which could provide potential targets for ovarian cancer diagnosis and treatment.

Knockdown of eIF4E suppresses cell proliferation, invasion and enhances cisplatin cytotoxicity in human ovarian cancer cells.

Eukaryotic initiation factor 4E (eIF4E) plays an important role in cap-dependent translation. The overexpression of eIF4E gene has been found in a variety of human malignancies. In this study, we attempted to identify the potential effects of eIF4E and explore the possibility of eIF4E as a therapeutic target for the treatment of human ovarian cancer. First the activation of eIF4E protein was detected with m7-GTP cap binding assays in ovarian cancer and control cells. Next, the eIF4E-shRNA expression plasmids were used to specifically inhibit eIF4E activity in ovarian cancer cells line A2780 and C200. The effects of knockdown eIF4E gene on cell proliferation, migration and invasion were investigated in vitro. Moreover, the changes of cell cycle and apoptosis of ovarian cancer cells were detected by flow cytometry. Finally, we investigated the effect of knockdown of eIF4E on the chemosensitivity of ovarian cancer cells to cisplatin in vitro. Our results show there is elevated activation of eIF4E in ovarian cancer cells compared with normal human ovarian epithelial cell line. The results of BrdU incorporation and FCM assay indicate that knockdown of eIF4E efficiently suppressed cell growth and induce cell cycle arrest in G1 phase and subsequent apoptosis in ovarian cancer cells. From Transwell assay analysis, knockdown eIF4E significantly decrease cellular migration and invasion of ovarian cancer cells. We also confirmed that knockdown eIF4E could synergistically enhance the cytotoxicity effects of cisplatin to cancer cells and sensitized cisplatin-resistant C200 cells in vitro. This study demonstrates that the activation of eIF4E gene is an essential component of the malignant phenotype in ovarian cancer, and aberration of eIF4E expression is associated with proliferation, migration, invasion and chemosensitivity to cisplatin in ovarian cancer cells. Knockdown eIF4E gene can be used as a potential therapeutic target for the treatment of human ovarian cancer.