New insights into pre-mRNA processing factor 19: A multi-faceted protein in humans

PRPF19 mRNA Encodes a Small Open Reading Frame That Is Important for Viability of Human Cells

High-throughput ribosome profiling demonstrates the translation of thousands of small open reading frames located in the 5' untranslated regions of messenger RNAs (upstream ORFs). Upstream ORF can both perform a regulatory function by influencing the translation of the downstream main ORF and encode a small functional protein or microprotein. In this work, we showed that the 5' untranslated region of the PRPF19 mRNA encodes an upstream ORF that is translated in human cells. Inactivation of this upstream ORF reduces the viability of human cells.

PRPF19 functions in DNA damage repair and gemcitabine sensitivity via regulating DDB1 in bladder cancer cells

PRPF19 seems to play either tumor-promoting or anti-tumor roles depending on cancer types. This study aimed to clarify the potential role and mechanism of PRPF19 in bladder cancer. PRPF19 expression and its correlation with patients' overall survival were analyzed in bladder cancer. The effects of PRPF19 on the viability, apoptosis, DNA damage repair, and gemcitabine sensitivity in human bladder cancer cells (T24 and 5637) were analyzed through loss- or gain-of-function methods. Moreover, the influences of DDB1 small interfering RNA on these indexes were evaluated in bladder cancer cells. At last, rescue experiment using DDB1 overexpression was carried out to confirm whether PRPF19 functioned via regulating DDB1. PRPF19 was highly expressed in bladder cancer tissues and cells. Elevated PRPF19 expression was related to shorter overall survival of bladder cancer patients. Downregulation of PRPF19 inhibited cell proliferation, promoted cell apoptosis, increased the number of γ-H2AX-positive cells, and reduced the mRNA and protein levels of DDB1 and BRCA1. Meanwhile, knockdown of PRPF19 decreased the IC50 of gemcitabine and promoted gemcitabine-induced cell apoptosis. Whereas, PRPF19 overexpression significantly decreased gemcitabine-induced apoptosis in bladder cancer cells. DDB1 downregulation suppressed cell proliferation and BRCA1 expression, but elevated the number of γ-H2AX-positive cells and gemcitabine sensitivity. Upregulation of DDB1 attenuated γ-H2AX-positive cell number, BRCA1 expression and IC50 of gemcitabine that were affected by PRPF19 silencing. In conclusion, PRPF19 expression was upregulated in bladder cancer. It promoted cell growth and DNA damage repair, and decreased gemcitabine sensitivity via positively regulating DDB1 expression.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-023-00599-7.

BIOINFORMATICS APPLICATIONS UNDER CONDITION CONTROL: HIGH DIAGNOSTIC VALUE OF DDX47 IN REAL MEDICAL SETTINGS

ABSTRACT

Sepsis is an organ dysfunction caused by a dysregulated host response to infection and remains an ongoing threat to human health worldwide. Septic shock is the most severe subset of sepsis as characterized by abnormalities in cells, circulation, and metabolism. As a time-dependent condition, early recognition allowing appropriate therapeutic measures to be started in a timely manner becomes the most effective way to improve prognosis. However, because of the lack of a criterion standard, most diagnoses merely rely on medical history, empirical diagnosis, and blood culture results. Gene expression profiles have specific diagnostic value, as they reflect a subjective host response to pathogens. We propose a method, Condition Control based on Real-life Medical Scenarios, to control for factors in realistic medical scenarios. Restricted variables are used as much as possible to identify unique differential genes and progressively test their diagnostic value by relaxing restrictions. In total, three data sets were included in the study; the first two data sets were from the Gene Expression Omnibus database, and the third involved patients who were diagnosed with sepsis or septic shock within 7 days of admission to the intensive care unit at West China Hospital of Sichuan University from 2020 to 2021. DDX47 showed preferable diagnostic value in various scenarios, especially in patients with common infections or sepsis and septic shock. Here we also show that hub genes may regulate immune function and immune cell counts through the interaction of different apoptotic pathways and immune checkpoints based on the high correlation. DDX47 is closely associated with B cells according to single-cell sequencing results.

Spatiotemporal Investigation of Intercellular Heterogeneity via Multiple Photocaged Probes

Intercellular heterogeneity occurs widely under both normal physiological environments and abnormal disease-causing conditions. Several attempts to couple spatiotemporal information to cell states in a microenvironment were performed to decipher the cause and effect of heterogeneity. Furthermore, spatiotemporal manipulation can be achieved with the use of photocaged/photoactivatable molecules. Here, we provide a platform to spatiotemporally analyze differential protein expression in neighboring cells by multiple photocaged probes coupled with homemade photomasks. We successfully established intercellular heterogeneity (photoactivable ROS trigger) and mapped the targets (directly ROS-affected cells) and bystanders (surrounding cells), which were further characterized by total proteomic and cysteinomic analysis. Different protein profiles were shown between bystanders and target cells in both total proteome and cysteinome. Our strategy should expand the toolkit of spatiotemporal mapping for elucidating intercellular heterogeneity.

PRPF19 promotes the proliferation, migration, and inhibits autophagy in prostate cancer by suppressing SLC40A1

Prostate cancer (PCa) is a common cancer and the leading cause of cancer-related death in men. To investigate the role of pre-mRNA processing factor 19 (PRPF19) in proliferation, migration of PCa, and evaluate the potential ability of PRPF19 as a therapeutic target. PRPF19 expression was analyzed from The Cancer Genome Atlas and GEPIA databank. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to evaluate the transcription of PRPF9 and solute carrier family 40 member 1 (SLC40A1). Immunohistochemistry (IHC) was used to test PRPF9 expression in PCa tissues. The cell viability and 5-ethynyl-2'-deoxyuridine incorporation analysis were performed to assess cell proliferation. Transwell assay was performed to investigate the migration and invasion of cancer cells. Western blot was used to measure the expression level of PRPF9, E-cadherin, Vimentin and α-smooth muscle actin (α-SMA), SLC40A1, LC3, Beclin-1 and ATG7. Immunofluorescence assay was performed to measure LC3 expression in PCa cells. The bioinformatic analysis revealed PRPF19 was highly expressed in PCa which was certified by qRT-PCR, western blot and IHC detection in PCa tissues. The proliferation of PCa cells could be promoted by PRPF19 overexpression and suppressed by PRPF19 knockdown. Moreover, the migration and invasion of PCa cells could be positively regulated by PRPF19 which promoted the expression of E-cadherin, Vimentin, and α-SMA. Furthermore, the expression of LC3, Beclin-1, and ATG7 was negatively regulated by PRPF19, indicating that PRPF19 inhibited autophagy in PCa cells. In the double knockdown of PRPF19 and SLC40A1, PRPF19 repressed the mRNA and reduced protein level of SLC40A1, and SLC40A1 antagonized effects of PRPF19 on proliferation, migration and autophagy of PCa cells. PRPF19 promoted proliferation and migration, and inhibited autophagy in PCa by attenuating SLC40A1 expression, indicating PRPF19 was a potential therapeutic target for PCa treatment.

Plasmodium DDI1 is a potential therapeutic target and important chromatin-associated protein

DNA damage inducible 1 protein (DDI1) is involved in a variety of cellular processes including proteasomal degradation of specific proteins. All DDI1 proteins contain a ubiquitin-like (UBL) domain and a retroviral protease (RVP) domain. Some DDI1 proteins also contain a ubiquitin-associated (UBA) domain. The three domains confer distinct activities to DDI1 proteins. The presence of a RVP domain makes DDI1 a potential target of HIV protease inhibitors, which also block the development of malaria parasites. Hence, we investigated the DDI1 of malaria parasites to identify its roles during parasite development and potential as a therapeutic target. DDI1 proteins of Plasmodium and other apicomplexan parasites share the UBL-RVP domain architecture, and some also contain the UBA domain. Plasmodium DDI1 is expressed across all the major life cycle stages and is important for parasite survival, as conditional depletion of DDI1 protein in the mouse malaria parasite Plasmodium berghei and the human malaria parasite Plasmodium falciparum compromised parasite development. Infection of mice with DDI1 knock-down P. berghei was self-limiting and protected the recovered mice from subsequent infection with homologous as well as heterologous parasites, indicating the potential of DDI1 knock-down parasites as a whole organism vaccine. Plasmodium falciparum DDI1 (PfDDI1) is associated with chromatin and DNA-protein crosslinks. PfDDI1-depleted parasites accumulated DNA-protein crosslinks and showed enhanced susceptibility to DNA-damaging chemicals, indicating a role of PfDDI1 in removal of DNA-protein crosslinks. Knock-down of PfDDI1 increased susceptibility to the retroviral protease inhibitor lopinavir and antimalarial artemisinin, which suggests that simultaneous inhibition of DDI1 could potentiate antimalarial activity of these drugs. As DDI1 knock-down parasites confer protective immunity and it could be a target of HIV protease inhibitors, Plasmodium DDI1 is a potential therapeutic target for malaria control.

PRPF19 Limits Porcine Epidemic Diarrhea Virus Replication through Targeting and Degrading Viral Capsid Protein

Porcine epidemic diarrhea (PED) indicates the disease of the acute and highly contagious intestinal infection due to porcine epidemic diarrhea virus (PEDV), with the characteristics of watery diarrhea, vomiting, and dehydration. One of the reasons for diarrhea and death of piglets is PEDV, which leads to 100% mortality in neonatal piglets. Therefore, it is necessary to explore the interaction between virus and host to prevent and control PEDV. This study indicated that the host protein, pre-mRNA processing factor 19 (PRPF19), could be controlled by the signal transducer as well as activator of transcription 1 (STAT1). Thus, PEDV replication could be hindered through selective autophagy. Moreover, PRPF19 was found to recruit the E3 ubiquitin ligase MARCH8 to the N protein for ubiquitination. For the purpose of degradation, the ubiquitin N protein is acknowledged by the cargo receptor NDP52 and transported to autolysosomes, thus inhibiting virus proliferation. To conclude, a unique antiviral mechanism of PRPF19-mediated virus restriction was shown. Moreover, a view of the innate immune response and protein degradation against PEDV replication was provided in this study. IMPORTANCE The highly virulent porcine epidemic diarrhea virus (PEDV) emerged in 2010, and causes high mortality rates in newborn pigs. There are no effective and safe vaccines against the highly virulent PEDV. This virus has caused devastating economic losses in the pork industry worldwide. Studying the relationship between virus and host antiviral factors is important to develop the new antiviral strategies. This study identified the pre-mRNA processing factor 19 (PRPF19) as a novel antiviral protein in PEDV replication and revealed its viral restriction mechanisms for the first time. PRPF19 recruited the E3 ubiquitin ligase MARCH8 to the PEDV N protein for ubiquitination, and the ubiquitin N protein was acknowledged by the cargo receptor NDP52 and transported to autolysosomes for degradation. Our findings provide new insights in host antiviral factors PRPF19 that regulate the selective autophagy protein degradation pathway to inhibit PEDV replication.

Genome-wide comparison and in silico analysis of splicing factor SYF2/NTC31/p29 in eukaryotes: Special focus on vertebrates

The gene SYF2—an RNA splicing factor—can interact with Cyclin D-type binding protein 1 (GICP) in many biological processes, including splicing regulation, cell cycle regulation, and DNA damage repair. In our previous study we performed genome-wide identification and functional analysis of SYF2 in plant species. The phylogenetic relationships and expression profiles of SYF2 have not been systematically studied in animals, however. To this end, the gene structure, genes, and protein conserved motifs of 102 SYF2 homologous genes from 91 different animal species were systematically analyzed, along with conserved splicing sites in 45 representative vertebrate species. A differential comparative analysis of expression patterns in humans and mice was made. Molecular bioinformatics analysis of SYF2 showed the gene was conserved and functional in different animal species. In addition, expression pattern analysis found that SYF2 was highly expressed in hematopoietic stem cells, T cells, and lymphoid progenitor cells; in ovary, lung, and spleen; and in other cells and organs. This suggests that changes in SYF2 expression may be associated with disease development in these cells, tissues, or organs. In conclusion, our study analyzes the SYF2 disease resistance genes of different animal species through bioinformatics, reveals the relationship between the SYF2 genotype and the occurrence of certain diseases, and provides a theoretical basis for follow-up study of the relationship between the SYF2 gene and animal diseases.

A U-Box Type E3 Ubiquitin Ligase Prp19-Like Protein Negatively Regulates Lipid Accumulation and Cell Size in Chlamydomonas reinhardtii

Microalgae lipid triacylglycerol is considered as a promising feedstock for national production of biofuels. A hotspot issue in the biodiesel study is to increase TAG content and productivity of microalgae. Precursor RNA processing protein (Prp19), which is the core component of eukaryotic RNA splice NTC (nineteen associated complex), plays important roles in the mRNA maturation process in eukaryotic cells, has a variety of functions in cell development, and is even directly involved in the biosynthesis of oil bodies in mouse. Nevertheless, its function in Chlamydomonas reinhardtii remains unknown. Here, transcriptional level of CrPrp19 under nutrition deprivation was analyzed, and both its RNA interference and overexpressed transformants were constructed. The expression level of CrPrp19 was suppressed by nitrogen or sulfur deficiency. Cell densities of CrPrp19 RNAi lines decreased, and their neutral lipid contents increased 1.33 and 1.34 times over those of controls. The cells of CrPrp19 RNAi lines were larger and more resistant to sodium acetate than control. Considerably none of the alterations in growth or neutral lipid contents was found in the CrPrp19 overexpression transformants than wild type. Fatty acids were also significantly increased in CrPrp19 RNAi transformants. Subcellular localization and yeast two-hybrid analysis showed that CrPrp19 was a nuclear protein, which might be involved in cell cycle regulation. In conclusion, CrPrp19 protein was necessary for negatively regulating lipid enrichment and cell size, but not stimulatory for lipid storage.

Prp19 Facilitated p21-Dependent Senescence of Hepatocellular Carcinoma Cells

Introduction

Evidence suggests that the role of senescence in the development of cancer is context-dependent. An orthologue of human pre-mRNA processing factor 19 (Prp19) attenuates the senescence of human endothelial cells. Prp19 has been reported to be involved in the progression of hepatocellular carcinoma (HCC). This work aims to investigate the effect of Prp19 on the senescence of HCC.

Materials and Methods

Senescence of L02 cells and HCC cells under different stimuli was detected through cell cycle analysis, SA-β-gal staining, and senescence associated secretory phenotype analysis. The relationship between Prp19 and senescence-related proteins was evaluated using real-time RT-PCR, western blot assay, and immunohistochemistry. Subcutaneous xenograft tumors in nude mice were used to evaluate the role of Prp19 on senescence in vivo. Data analysis was carried out using GraphPad Prism 6.

Results

Prp19 facilitated the senescence of L02 cells and HCC cells under different stresses. Prp19 positively modulated p21 expression in the mRNA level. Downregulation of Prp19 promoted the growth of subcutaneous xenograft tumors generated by HCC cell lines.

Conclusions

Prp19 may promote senescence of HCC cells via regulating p21 expression.

Pre-mRNA processing factor 19 functions in DNA damage repair and radioresistance by modulating cyclin D1 in hepatocellular carcinoma

Pre-mRNA processing factor 19 (PRP19) is elevated in hepatocellular carcinoma (HCC); however, little is known about its function in DNA damage repair in HCC. In this study, analysis of The Cancer Genome Atlas data and our tumor models after ionizing radiation (IR) treatment indicated that increased expression of PRP19 was positively correlated with DNA damage repair. Gain of PRP19 expression induced by plasmids resulted in decreases in apoptosis and double-strand breaks (DSBs), and an increase in cell survival after IR. Loss of PRP19 expression induced by small interfering RNAs resulted in the accumulation of apoptosis and DSBs, and a decrease in cell survival. Mechanistically, the effect of PRP19 on DNA damage repair was mediated by the modulation of cyclin D1 expression in HCC. PRP19 controlled the translation of cyclin D1 by modulating eukaryotic initiation factor 4E. PRP19 affected the DNA damage repair ability of cyclin D1 by interacting with the WD40 domain. The combination of PRP19 and cyclin D1 was more valuable than each single marker for predicting the prognosis of patients. Taken together, the present results demonstrate that PRP19 promotes DNA damage repair by modulating cyclin D1 expression and function, thereby contributing to the radioresistance in HCC.

Hsp90-associated DNA replication checkpoint protein and proteasome-subunit components are involved in the age-related macular degeneration

Background:

Age-related macular degeneration (AMD) is the leading cause of vision loss worldwide. However, the mechanisms involved in the development and progression of AMD are poorly delineated. We aimed to explore the critical genes involved in the progression of AMD.

Methods:

The differentially expressed genes (DEGs) in AMD retinal pigment epithelial (RPE)/choroid tissues were identified using the microarray datasets GSE99248 and GSE125564, which were downloaded from the gene expression omnibus database. The overlapping DEGs from the two datasets were screened to identify DEG-related biological pathways using gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. The hub genes were identified from these DEGs through protein-protein interaction network analyses. The expression levels of hub genes were evaluated by quantitative real-time polymerase chain reaction following the induction of senescence in ARPE-19 with FK866. Following the identification of AMD-related key genes, the potential small molecule compounds targeting the key genes were predicted by PharmacoDB. Finally, a microRNA-gene interaction network was constructed.

Results:

Microarray analyses identified 174 DEGs in the AMD RPE compared to the healthy RPE samples. These DEGs were primarily enriched in the pathways involved in the regulation of DNA replication, cell cycle, and proteasome-mediated protein polyubiquitination. Among the top ten hub genes, HSP90AA1, CHEK1, PSMA4, PSMD4, and PSMD8 were upregulated in the senescent ARPE-19 cells. Additionally, the drugs targeting HSP90AA1, CHEK1, and PSMA4 were identified. We hypothesize that Hsa-miR-16-5p might target four out of the five key DEGs in the AMD RPE.

Conclusions:

Based on our findings, HSP90AA1 is likely to be a central gene controlling the DNA replication and proteasome-mediated polyubiquitination during the RPE senescence observed in the progression of AMD. Targeting HSP90AA1, CHEK1, PSMA4, PSMD4, and/or PSMD8 genes through specific miRNAs or small molecules might potentially alleviate the progression of AMD through attenuating RPE senescence.

PRPF19 promotes tongue cancer growth and chemoradiotherapy resistance

Pre-mRNA processing factor 19 (PRPF19) is a multifaceted protein and participates in DNA damage response and pre-mRNA processing. The role of PRPF19 in cancer is unclear. Here, we report that the expression of PRPF19 in human tongue cancer is associated with unfavorable prognosis. Overexpression of PRPF19 promotes while knockdown of PRPF19 inhibits tongue cancer cell migration, proliferation, and tumor growth. Overexpression of PRPF19 increases the resistance of tongue cancer cells to radiation and cisplatin treatment. Furthermore, PRPF19 regulates the expression of solute carrier family 40 member 1 (SLC40A1) and mono-ADP ribosylhydrolase 2 (MACROD2), knockdown of SLC40A1 or MACROD2 decreases the sensitivity of tongue cancer cells to radiation and cisplatin treatment. Thus, our results establish a key role of PRPF19 in tongue cancer growth and chemoradiotherapy resistance, targeting PRPF19 would be an effective therapeutic strategy for tongue cancer, especially for those resistant to chemoradiotherapy.

PRPF19 regulates p53-dependent cellular senescence by modulating alternative splicing of MDM4 mRNA

Alteration of RNA splicing is a hallmark of cellular senescence, which is associated with age-related disease and cancer development. However, the roles of splicing factors in cellular senescence are not fully understood. In this study, we identified the splicing factor PRPF19 as a critical regulator of cellular senescence in normal human diploid fibroblasts. PRPF19 was downregulated during replicative senescence, and PRPF19 knockdown prematurely induced senescence-like cell cycle arrest through the p53–p21 pathway. RNA-sequencing analysis revealed that PRPF19 knockdown caused a switch of the MDM4 splicing isoform from stable full-length MDM4-FL to unstable MDM4-S lacking exon 6. We also found that PRPF19 regulates MDM4 splicing by promoting the physical interaction of other splicing factors, PRPF3 and PRPF8, which are key components of the core spliceosome, U4/U6.U5 tri-snRNP. Given that MDM4 is a major negative regulator of p53, our findings imply that PRPF19 downregulation inhibits MDM4-mediated p53 inactivation, resulting in induction of cellular senescence. Thus, PRPF19 plays an important role in the induction of p53-dependent cellular senescence.

Gene Expression Changes and Associated Pathways Involved in the Progression of Prostate Cancer Advanced Stages

Prostate cancer (PC) is one of the most common cancers among men worldwide, and advanced PCs, such as locally advanced PC (LAPC) and castration-resistant PC (CRPC), present the greatest challenges in clinical management. Current indicators have limited capacity to predict the disease course; therefore, better prognostic markers are greatly needed. In this study, we performed a bioinformatic analysis of The Cancer Genome Atlas (TCGA) datasets, including RNA-Seq data from the prostate adenocarcinoma (PRAD; n = 55) and West Coast Dream Team – metastatic CRPC (WCDT-MCRPC; n = 84) projects, to evaluate the transcriptome changes associated with progression-free survival (PFS) for LAPC and CRPC, respectively. We identified the genes whose expression was positively/negatively correlated with PFS. In LAPC, the genes with the most significant negative correlations were ZC2HC1A, SQLE, and KIF11, and the genes with the most significant positive correlations were SOD3, LRRC26, MIR22HG, MEG3, and MIR29B2CHG. In CRPC, the most significant positive correlations were found for BET1, CTAGE5, IFNGR1, and GIMAP6, and the most significant negative correlations were found for CLPB, PRPF19, ZNF610, MPST, and LINC02001. In addition, we performed a gene network interaction analysis using STRINGdb, which revealed a significant relationship between genes predominantly involved in the cell cycle and characterized by upregulated expression in early recurrence. Based on the results, we propose several genes that can be used as potential prognostic markers.

Prp19 Is an Independent Prognostic Marker and Promotes Neuroblastoma Metastasis by Regulating the Hippo-YAP Signaling Pathway

Pre-mRNA processing factor 19 (Prp19) was previously reported to be involved in tumor progression. However, Prp19 expression and its functions remain elusive in neuroblastoma. Here, we aim to identify the functions and mechanisms of Prp19 in neuroblastoma. Neuroblastic tumor tissue microarrays and two independent validation data sets indicate that Prp19 is associated with high-risk markers and bone marrow metastasis and serves as a prognostic marker for worse clinical outcomes with neuroblastoma. Gain- and loss-of-expression assays reveal that Prp19 promotes invasion, migration, and epithelial-mesenchymal transition (EMT) of neuroblastoma cells in vitro. Bioinformatics analysis of RNA-seq data shows that the expressions of YAP and its downstream genes are significantly inhibited after downregulation of Prp19. Prp19 and YAP expression in metastatic lymph nodes is higher than in situ neuroblastoma tissue. Further experiments show that Prp19 regulates YAP expression and consequently affects cell invasion, migration, and EMT in neuroblastoma by pre-mRNA splicing of YAP. In conclusion, our findings provide the first evidence that Prp19 is a potential therapeutic target and prognostic biomarker for patients with neuroblastoma.

Methylome analyses of three glioblastoma cohorts reveal chemotherapy sensitivity markers within DDR genes

BACKGROUND

Gliomas evade current therapies through primary and acquired resistance and the effect of temozolomide is mainly restricted to methylguanin-O6-methyltransferase promoter (MGMT) promoter hypermethylated tumors. Further resistance markers are largely unknown and would help for better stratification.

METHODS

Clinical data and methylation profiles from the NOA-08 (104, elderly glioblastoma) and the EORTC 26101 (297, glioblastoma) studies and 398 patients with glioblastoma from the Heidelberg Neuro-Oncology center have been analyzed focused on the predictive effect of DNA damage response (DDR) gene methylation. Candidate genes were validated in vitro.

RESULTS

Twenty-eight glioblastoma 5'-cytosine-phosphat-guanine-3' (CpGs) from 17 DDR genes negatively correlated with expression and were used together with telomerase reverse transcriptase (TERT) promoter mutations in further analysis. CpG methylation of DDR genes shows highest association with the mesenchymal (MES) and receptor tyrosine kinase (RTK) II glioblastoma subgroup. MES tumors have lower tumor purity compared to RTK I and II subgroup tumors. CpG hypomethylation of DDR genes TP73 and PRPF19 correlated with worse patient survival in particular in MGMT promoter unmethylated tumors. TERT promoter mutation is most frequent in RTK I and II subtypes and associated with worse survival. Primary glioma cells show methylation patterns that resemble RTK I and II glioblastoma and long term established glioma cell lines do not match with glioblastoma subtypes. Silencing of selected resistance genes PRPF19 and TERT increase sensitivity to temozolomide in vitro.

CONCLUSION

Hypomethylation of DDR genes and TERT promoter mutations is associated with worse tumor prognosis, dependent on the methylation cluster and MGMT promoter methylation status in IDH wild-type glioblastoma.

Prp19 facilitates invasion of hepatocellular carcinoma via p38 mitogen-activated protein kinase/twist1 pathway

Pre-mRNA processing factor 19 (Prp19) is involved in many cellular events including pre-mRNA processing and DNA damage response. However, the pathological role of Prp19 in hepatocellular carcinoma (HCC) is still elusive. Here, we reported that Prp19 was increased in most HCC tissues and HCC cell lines, and its overexpression in HCC tissues was positively correlated with vascular invasion, tumor capsule breakthrough and poor prognosis. Prp19 potentiated migratory and invasive abilities of HCC cells in vitro and in vivo. Furthermore Prp19 facilitated Twist1-induced epithelial-mesenchymal transition. Mechanistic insights revealed that Prp19 directly binded with TGF-β-activated kinase1 (TAK1) and promoted the activation of p38 mitogen-activated protein kinase (MAPK), preventing Twist1 from degradation. Finally Prp19/p38 MAPK/Twist1 axis was attested in nude mice xenografts and HCC patient specimens. This work implies that the gain of Prp19 is a critical event during the progression of HCC, making it a promising target for malignancies with aberrant Prp19 expression.

Prp19 Arrests Cell Cycle via Cdc5L in Hepatocellular Carcinoma Cells

Pre-mRNA processing factor 19 (Prp19) is involved in many cellular events including pre-mRNA processing and DNA damage response. Recently, it has been identified as a candidate oncogene in hepatocellular carcinoma (HCC). However, the role of Prp19 in tumor biology is still elusive. Here, we reported that Prp19 arrested cell cycle in HCC cells via regulating G2/M transition. Mechanistic insights revealed that silencing Prp19 inhibited the expression of cell division cycle 5-like (Cdc5L) via repressing the translation of Cdc5L mRNA and facilitating lysosome-mediated degradation of Cdc5L in HCC cells. Furthermore, we found that silencing Prp19 induced cell cycle arrest could be partially resumed by overexpressing Cdc5L. This work implied that Prp19 participated in mitotic progression and thus could be a promising therapeutic target of HCC.

Unraveling molecular effects of ADAR1 overexpression in HEK293T cells by label-free quantitative proteomics

ADAR1 is a double-stranded RNA (dsRNA) editing enzyme that specifically converts adenosine to inosine. ADAR1 is ubiquitously expressed in eukaryotes and participate in various cellular processes such as differentiation, proliferation and immune responses. We report here a new proteomics study of HEK293T cells with and without ADAR1 overexpression. The up- and down-regulated proteins by ADAR1 overexpression are identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by label-free protein quantification. Totally 1,495 proteins (FDR < 0.01) are identified, among which 211 are up- and 159 are down-regulated for at least 1.5-fold (n = 3, p < 0.05). Gene ontology analysis reveals that these ADAR1-regulated proteins are involved in protein translation and cell cycle regulation. Bioinformatics analysis identifies a closely related network consistent for the protein translation machinery and a tightly connected network through proliferating cell nuclear antigen (PCNA)-interactions. Up-regulation of the proteins in the PCNA-mediated cell proliferation network is confirmed by Western blotting. In addition, ADAR1 overexpression is confirmed to increase cell proliferation in HEK293T cells and A549 cells. We conclude that ADAR1 overexpression modulates the protein translation and cell cycle networks through PCNA-mediated protein-protein interaction to promote cell proliferation in HEK293 cells.

DNA damage induces down-regulation of Prp19 via impairing Prp19 stability in hepatocellular carcinoma cells

Pre-mRNA processing factor 19 (Prp19) activates pre-mRNA spliceosome and also mediates DNA damage response. Prp19 overexpression in cells with functional p53 leads to decreased apoptosis and increases cell survival after DNA damage. Here we showed that in hepatocellular carcinoma (HCC) cells with inactive p53 or functional p53, Prp19 was down-regulated due to the impaired stability under chemotherapeutic drug treatment. Silencing Prp19 expression enhanced apoptosis of HCC cells with or without chemotherapeutic drug treatment. Furthermore high level of Prp19 may inhibit chemotherapeutic drugs induced apoptosis in hepatocellular carcinoma cells through modulating myeloid leukemia cell differentiation 1 expression. These results indicated that targeting Prp19 may potentiate pro-apoptotic effect of chemotherapeutic agents on HCC.

Splicing and beyond: the many faces of the Prp19 complex

The conserved Prp19 complex (Prp19C) - also known as NineTeen Complex (NTC) - functions in several processes of paramount importance for cellular homeostasis. NTC/Prp19C was discovered as a complex that functions in splicing and more specifically during the catalytic activation of the spliceosome. More recent work revealed that NTC/Prp19C plays a role in transcription elongation in Saccharomyces cerevisiae and in genome maintenance in higher eukaryotes. In addition, mouse PRP19 might ubiquity late proteins targeted for degradation and guide them to the proteasome. Furthermore, NTC/Prp19C has been implicated in lipid droplet biogenesis. In the future, the molecular function of NTC/Prp19C in all of these processes needs to be refined or elucidated. Most of NTC/Prp19C's functions have been shown in only one or few organisms. However, since this complex is highly conserved it is likely that it has the same functions across all species. Moreover, one NTC/Prp19C or different subcomplexes could function in the above-mentioned processes. Intriguingly, NTC/Prp19C might link these different processes to ensure an optimal coordination of cellular processes. Thus, many important questions about the functions of this interesting complex remain to be investigated. In this review we discuss the different functions of NTC/Prp19C focusing on the novel and emerging ones as well as open questions.