PDRG1, a novel tumor marker for multiple malignancies that is selectively regulated by genotoxic stress

Analysis of Vascular Smooth Muscle Cells from Thoracic Aortic Aneurysms Reveals DNA Damage and Cell Cycle Arrest as Hallmarks in Bicuspid Aortic Valve Patients

Thoracic aortic aneurysm (TAA) is mainly sporadic and with higher incidence in the presence of a bicuspid aortic valve (BAV) for unknown reasons. The lack of drug therapy to delay TAA progression lies in the limited knowledge of pathophysiology. We aimed to identify the molecular hallmarks that differentiate the aortic dilatation associated with BAV and tricuspid aortic valve (TAV). Aortic vascular smooth muscle cells (VSMCs) isolated from sporadic TAA patients with BAV or TAV were analyzed by mass spectrometry. DNA oxidative damage assay and cell cycle profiling were performed in three independent cohorts supporting proteomics data. The alteration of secreted proteins was confirmed in plasma. Stress phenotype, oxidative stress, and enhanced DNA damage response (increased S-phase arrest and apoptosis) were found in BAV-TAA patients. The increased levels of plasma C1QTNF5, LAMA2, THSB3, and FAP confirm the enhanced stress in BAV-TAA. Plasma FAP and BGN point to an increased inflammatory condition in TAV. The arterial wall of BAV patients shows a limited capacity to counteract drivers of sporadic TAA. The molecular pathways identified support the need of differential molecular diagnosis and therapeutic approaches for BAV and TAV patients, showing specific markers in plasma which may serve to monitor therapy efficacy.

A pan-cancer analysis of the expression and prognostic significance of PDRG1

Background

PDRG1 are involved in various physiological regulations of cells, include cell proliferation, growth, apoptosis and cell cycle regulation, but their roles in cancer have not been clearly studied.

Methods

Firstly, we evaluated the expression and prognostic significance of PDRG1 using a pan-cancer analysis of The Cancer Genome Atlas (TCGA) and Genotypic Tissue Expression (GTEx) databases. Secondly, correlations between PDRG1 and pan-cancer immune cells, m6A methylation, tumor mutation burden (TMB), and microsatellite instability (MSI) were investigated. Finally, we explored the relationship between PDRG1 expression and clinical stage in hepatocellular carcinoma (HCC).

Results

We found that PDRG1 was significantly overexpressed in bladder urothelial carcinoma (BLCA), breast invasive carcinoma (BRCA), cholangiocarcinoma (CHOL), liver hepatocellular carcinoma (LIHC), and other tumor tissues and was associated with prognosis. In addition, PDRG1 was closely associated with pan-cancer immune cells, m6A methylation, TMB, and MSI expression. The expression of PDRG1 in HCC was correlated with clinical stage, and western blot assay confirmed that PDRG1 was significantly overexpressed in HCC tissues.

Conclusions

PDRG1 may be an important pan-cancer molecular biomarker for diagnosis and prognosis, and our results may provide a theoretical basis for its future clinical application in cancer diagnosis, treatment, and prognosis, and have been preliminarily validated in HCC.

PDRG1 promotes the proliferation and migration of GBM cells by the MEK/ERK/CD44 pathway

P53 and DNA damage‐regulated gene1 (PDRG1) is overexpressed in diverse carcinomas. Here, we discover that PDRG1 is overexpressed in glioblastoma multiforme (GBM). However, the clinical significance, biological role, and underlying molecular mechanisms of PDRG1 in GBM remain unclear. PDRG1 was aberrantly overexpressed in glioma, especially prevalent in GBM, and correlated with poor clinicopathologic features of glioma. The risk score, operational feature curve analysis, Kaplan‐Meier curve, and univariate and multivariate Cox regression analysis indicated that PDRG1 was an independent prognostic indicator and significantly correlates with disease progression of glioma. A prognostic nomogram was constructed to predict the survival risk of individual patients. The function and pathway enrichment analysis of PDRG1 in The Cancer Genome Atlas cohort was performed. PDRG1 knockdown significantly inhibited the migration and proliferation of GBM cells in vitro and in vivo. Transcriptome sequencing analysis of PDRG1 knockdown U‐118 MG(U118) cells indicated that biological regulation adhesion, growth and death, cell motility, cell adhesion molecular and proteoglycans in cancer were significantly enriched. Importantly, we found that the expression of adhesion molecule cluster of differentiation 44 (CD44) was regulated by PDRG1 in GBM. We found that PDRG1 promoted the migration and proliferation of GBM cells via the mitogen‐activated protein kinase kinase (MEK)/extracellular regulated protein kinase (ERK)/CD44 pathway. Our findings provide proof that PDRG1 upregulation predicts progression and poor prognosis in human gliomas, especially in isocitrate dehydrogenase (IDH) wt glioma patients. The study provides new evidence that PDRG1 regulates the expression of CD44 in GBM cells and might promote the migration and proliferation via the MEK/ERK/CD44pathway. PDRG1 might be a novel diagnostic indicator and promising therapeutic target for GBM.

PDRG1 predicts a poor prognosis and facilitates the proliferation and metastasis of colorectal cancer

OBJECTIVE

The incidence and mortality of colorectal cancer (CRC) is increasing yearly and CRC patients are becoming younger in global. Evidences have revealed the carcinogenic effect of p53 and DNA damage-regulated gene 1 (PDRG1) in several types of tumors. However, its biological function is yet to be investigated in CRC. This study aimed to unveil the prooncogenic role of PDRG1 in CRC.

METHODS

We detected the expression and clinical pathological features of PDRG1 in CRC tissues and paired non-tumor adjacent tissues. The biological role and molecular mechanism of PDRG1 in CRC were characterized through a range of in vitro and in vivo experiments and datasets analysis.

RESULT

We identified the significant up-regulated expression of PDRG1 both in CRC tissues and cell, and higher expression of PDRG1 was associated with worse clinicopathological stage and poorer survival outcome. Cox regression analysis revealed that PDRG1 is an independent prognostic factor for CRC patients. Silencing of PDRG1 significantly retarded CRC cell vitality, invasion and migration, induced cell apoptosis and G0/G1 phase arrest. PDRG1 knockdown also attenuated tumor growth and metastasis as evidencing in vivo experiment. The expression of p21 and apoptosis related protein was enhanced with the knockdown of PDRG1 while cell cycle protein was inhibited.

CONCLUSION

PDRG1 function as a novel oncogene and participate in malignant progression of CRC by regulating p21-mediated signal pathway, suggesting that it can serve as a valuable predictive biomarker for diagnosing of CRC patient and a promising target for therapy.

Tinospora cordifolia ameliorated titanium dioxide nanoparticle-induced toxicity via regulating oxidative stress-activated MAPK and NRF2/Keap1 signaling pathways in Nile tilapia (Oreochromis niloticus)

Titanium dioxide nanoparticle (TNP) has been suggested for use in fish farms to prevent or alleviate bacterial diseases owing to its bactericidal property. Unfortunately, the interaction of TNP with cells impaired the host defenses of fish resulting in increased mortality during bacterial challenges. The present study evaluated the efficacy of the ethanolic extract of Tinospora cordifolia (TCE) as a dietary supplement in ameliorating TNP induced toxicity in Nile tilapia (Oreochromis niloticus). The fishes were exposed to environmentally relevant concentration (10 mg/L) of TNP for 14 days and the effect of TCE supplemented feed at 3 different doses (5, 10, and 15 g/kg) was studied. TCE signally increased the weight gain, specific growth rate, and decreased feed conversion ratio in fish. TCE significantly (P < 0.05) ameliorated the toxic effects caused by TNP by increasing the antioxidant (CAT, SOD, GPx) activity and decreasing the levels of serum enzymes (ALT, AST, ALP, ACP), macromolecular oxidation, excessive ROS production, and pro-inflammatory cytokines (IL-1β, IL-6, IL-8, INF-γ, TNF-α, PGE-2). TNP bioaccumulation and histopathological alterations in gill, liver, and kidney were also significantly alleviated by TCE supplementation. TCE perceptibly regulated the expression of heat shock proteins (HSP60, -70), MAPKs (pERK1/2, pp38), antioxidant (NRF2, Keap1, HO-1), apoptotic (p53, PDRG1), and anti-apoptotic (AKT, Bcl2) proteins in fish. Regarding disease resistance, the TCE co-treated groups showed reduced cumulative mortality and higher relative percent survival with A. hydrophila. Our results suggest that TNP-induced apoptosis is mediated by the MAPK/NRF2/Keap1 pathway and underlines the therapeutic potential of TCE in aqua-farming.

Heat stress-induced expression of Px-pdrg and Px-aspp2 in insecticide-resistant and -susceptible Plutella xylostella

p53, DNA damage regulated gene (PDRG) and apoptosis-stimulating p53 protein 2 (ASPP2) are p53-related genes which can promote apoptosis. The full-length cDNA sequence of the Px-pdrg and Px-aspp2 genes were characterized and their mRNA expression dynamics under heat stress were studied in diamondback moth (DBM) Plutella xylostella collected from Fuzhou, China. The full-length cDNA of Px-pdrg and Px-aspp2 spans 721 and 4201 bp, containing 395 and 3216 bp of the open reading frame, which encode a putative protein comprising 130 and 1072 amino acids with a calculated molecular weight of 14.58 and 118.91 kDa, respectively. As compared to 25°C, both Px-pdrg and Px-aspp2 were upregulated in chlorpyrifos-resistant (Rc) and -susceptible (Sm) strains of DBM adults and pupae under heat stress. In addition, Rc DBM showed a significantly higher expression level of Px-pdrg and Px-aspp2 in contrast to Sm DBM. The results indicate that high temperature can significantly promote apoptosis process, especially in Rc-DBM. Significant fitness cost in Rc-DBM might be associated with drastically higher transcript abundance of Px-pdrg and Px-aspp2 under the heat stress.

Methionine adenosyltransferases in liver cancer

Methionine adenosyltransferases (MATs) are essential enzymes for life as they produce S-adenosylmethionine (SAMe), the biological methyl donor required for a plethora of reactions within the cell. Mammalian systems express two genes, MAT1A and MAT2A, which encode for MATα1 and MATα2, the catalytic subunits of the MAT isoenzymes, respectively. A third gene MAT2B, encodes a regulatory subunit known as MATβ which controls the activity of MATα2. MAT1A, which is mainly expressed in hepatocytes, maintains the differentiated state of these cells, whilst MAT2A and MAT2B are expressed in extrahepatic tissues as well as non-parenchymal cells of the liver (e.g., hepatic stellate and Kupffer cells). The biosynthesis of SAMe is impaired in patients with chronic liver disease and liver cancer due to decreased expression and inactivation of MATα1. A switch from MAT1A to MAT2A/MAT2B occurs in multiple liver diseases and during liver growth and dedifferentiation, but this change in the expression pattern of MATs results in reduced hepatic SAMe level. Decades of study have utilized the Mat1a-knockout (KO) mouse that spontaneously develops non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) to elucidate a variety of mechanisms by which MAT proteins dysregulation contributes to liver carcinogenesis. An increasing volume of work indicates that MATs have SAMe-independent functions, distinct interactomes and multiple subcellular localizations. Here we aim to provide an overview of MAT biology including genes, isoenzymes and their regulation to provide the context for understanding consequences of their dysregulation. We will highlight recent breakthroughs in the field and underscore the importance of MAT’s in liver tumorigenesis as well as their potential as targets for cancer therapy.

CIZ1-F, an alternatively spliced variant of the DNA replication protein CIZ1 with distinct expression and localisation, is overrepresented in early stage common solid tumours

CIZ1 promotes cyclin-dependent DNA replication and resides in sub-nuclear foci that are part of the protein nuclear matrix (NM), and in RNA assemblies that are enriched at the inactive X chromosome (Xi) in female cells. It is subjected to alternative splicing, with specific variants implicated in adult and pediatric cancers. CIZ1-F is characterized by a frame shift that results from splicing exons 8–12 leading to inclusion of a short alternative reading frame (ARF), excluding the previously characterized C-terminal NM anchor domain. Here, we apply a set of novel variant-selective molecular tools targeted to the ARF to profile the expression of CIZ1-F at both transcript and protein levels, with focus on its relationship with the RNA-dependent and -independent fractions of the NM. Unlike full-length CIZ1, CIZ1-F does not accumulate at Xi, though like full-length CIZ1 it does resist extraction with DNase. Notably, CIZ1-F is sensitive to RNase identifying it as part of the RNA-fraction of the NM. In quiescent cells CIZ1-F transcript expression is suppressed and CIZ1-F protein is excluded from the nucleus, with re-expression not observed until the second cell cycle after exit from quiescence. Importantly, CIZ1-F is over-expressed in common solid tumors including colon and breast, pronounced in early stage but not highly-proliferative late stage tumors. Moreover, expression was significantly higher in hormone receptor negative breast tumors than receptor positive tumors. Together these data show that CIZ1-F is expressed in proliferating cells in an unusual cell cycle-dependent manner, and suggest that it may have potential as a tumor biomarker.

The influence of retinoic acid-induced differentiation on the radiation response of male germline stem cells

Lifelong mammalian male fertility is maintained through an intricate balance between spermatogonial proliferation and differentiation. DNA damage in spermatogonia, for instance caused by chemo- or radiotherapy, can induce cell cycle arrest or germ cell apoptosis, possibly resulting in male infertility. Spermatogonia are generally more radiosensitive and prone to undergo apoptosis than somatic cells. Among spermatogonial subtypes the response to DNA damage is differentially modulated; undifferentiated spermatogonia, including the spermatogonial stem cells (SSCs), are relatively radio-resistant, whereas differentiating spermatogonia are very radiosensitive. To investigate the molecular mechanisms underlying this difference, we used an in vitro system consisting of mouse male germline stem (GS) cells that can be induced to differentiate. Using RNA-sequencing analysis, we analyzed the response of undifferentiated and differentiating GS cells to ionizing radiation (IR). At the RNA expression level, both undifferentiated and differentiating GS cells showed a very similar response to IR. Protein localization of several genes found to be involved in either spermatogonial differentiation or radiation response was investigated using mouse testis sections. For instance, we found that the transcription factor PDX1 was specifically expressed in undifferentiated spermatogonia and thus may be a novel marker for these cells. Interestingly, also at the protein level, undifferentiated GS cells showed a more pronounced upregulation of p53 in response to IR than differentiating GS cells. The higher p53 protein level in undifferentiated spermatogonia may preferentially induce cell cycle arrest, thereby giving these cells more time to repair inflicted DNA damage and increase their radio-resistance.

Mammalian Sulfur Amino Acid Metabolism: A Nexus Between Redox Regulation, Nutrition, Epigenetics, and Detoxification

SIGNIFICANCE

Transsulfuration allows conversion of methionine into cysteine using homocysteine (Hcy) as an intermediate. This pathway produces S-adenosylmethionine (AdoMet), a key metabolite for cell function, and provides 50% of the cysteine needed for hepatic glutathione synthesis. The route requires the intake of essential nutrients (e.g., methionine and vitamins) and is regulated by their availability. Transsulfuration presents multiple interconnections with epigenetics, adenosine triphosphate (ATP), and glutathione synthesis, polyol and pentose phosphate pathways, and detoxification that rely mostly in the exchange of substrates or products. Major hepatic diseases, rare diseases, and sensorineural disorders, among others that concur with oxidative stress, present impaired transsulfuration. Recent Advances: In contrast to the classical view, a nuclear branch of the pathway, potentiated under oxidative stress, is emerging. Several transsulfuration proteins regulate gene expression, suggesting moonlighting activities. In addition, abnormalities in Hcy metabolism link nutrition and hearing loss.

CRITICAL ISSUES

Knowledge about the crossregulation between pathways is mostly limited to the hepatic availability/removal of substrates and inhibitors. However, advances regarding protein-protein interactions involving oncogenes, identification of several post-translational modifications (PTMs), and putative moonlighting activities expand the potential impact of transsulfuration beyond methylations and Hcy.

FUTURE DIRECTIONS

Increasing the knowledge on transsulfuration outside the liver, understanding the protein-protein interaction networks involving these enzymes, the functional role of their PTMs, or the mechanisms controlling their nucleocytoplasmic shuttling may provide further insights into the pathophysiological implications of this pathway, allowing design of new therapeutic interventions. Antioxid. Redox Signal. 29, 408-452.

Genome-wide copy number analyses of samples from LACE-Bio project identify novel prognostic and predictive markers in early stage non-small cell lung cancer

Background

Adjuvant chemotherapy (ACT) provides modest benefit in resected non-small cell lung cancer (NSCLC) patients. Genome-wide studies have identified gene copy number aberrations (CNA), but their prognostic implication is unknown.

Methods

DNA from 1,013 FFPE tumor samples from three pivotal multicenter randomized trials (ACT vs. control) in the LACE-Bio consortium (median follow-up: 5.2 years) was successfully extracted, profiled using a molecular inversion probe SNP assay, normalized relative to a pool of normal tissues and segmented. Minimally recurrent regions were identified. P values were adjusted to control the false discovery rate (Q values).

Results

A total of 976 samples successfully profiled, 414 (42%) adenocarcinoma (ADC), 430 (44%) squamous cell carcinoma (SCC) and 132 (14%) other NSCLC; 710 (73%) males. We identified 431 recurrent regions, with on average 51 gains and 43 losses; 253 regions (59%) were ≤3 Mb. Most frequent gains (up to 48%) were on chr1, 3q, 5p, 6p, 8q, 22q; most frequent losses (up to 40%) on chr3p, 8p, 9p. CNA frequency of 195 regions was significantly different (Q≤0.05) between ADC and SCC. Fourteen regions (7p11-12, 9p21, 18q12, and 19p11-13) were associated with disease-free survival (DFS) (univariate P≤0.005, Q<0.142), with poorer DFS for losses of regions including CDKN2A/B [hazard ratio (HR) for 2-fold lower CN: 1.5 (95% CI: 1.2-1.9), P<0.001, Q=0.020] and STK11 [HR =2.4 (1.3-4.3), P=0.005, Q=0.15]. Chromosomal instability was associated with poorer DFS (HR =1.5, P=0.015), OS (HR =1.2, P=0.189) and lung-cancer specific survival (HR =1.7, P=0.003).

Conclusions

These large-scale genome-wide analyses of gene CNA provide new candidate prognostic markers for stage I-III NSCLC.

The Potential Roles of the Apoptosis-Related Protein PDRG1 in Diapause Embryo Restarting of Artemia sinica

High salinity and low temperatures can induce Artemia sinica to enter the diapause stage during embryonic development. Diapause embryos stop at the gastrula stage, allowing them to resist apoptosis and regulate cell cycle activity to guarantee normal development after diapause termination. P53 and DNA damage-regulated gene 1 (pdrg1) is involved in cellular physiological activities, such as apoptosis, DNA damage repair, cell cycle regulation, and promotion of programmed cell death. However, the role of pdrg1 in diapause and diapause termination in A. sinica remains unknown. Here, the full-length A. sinica pdrg1 cDNA (As-pdrg1) was obtained and found to contain 1119 nucleotides, including a 228 bp open reading frame (ORF), a 233 bp 5'-untranslated region (UTR), and a 658-bp 3'-UTR, which encodes a 75 amino acid protein. In situ hybridization showed no tissue specific expression of As-pdrg1. Quantitative real-time PCR and western blotting analyses of As-pdrg1 gene and protein expression showed high levels at 15-20 h of embryo development and a subsequent downward trend. Low temperatures upregulated As-pdrg1 expression. RNA interference for the pdrg1 gene in Artemia embryos caused significant developmental hysteresis. Thus, PDRG1 plays an important role in diapause termination and cell cycle regulation in early embryonic development of A. sinica.

Role of the PAQosome in Regulating Arrangement of Protein Quaternary Structure in Health and Disease

The PAQosome, formerly known as the R2TP/PFDL complex, is an eleven-subunit cochaperone complex that assists HSP90 in the assembly of numerous large multisubunit protein complexes involved in essential cellular functions such as protein synthesis, ribosome biogenesis, transcription, splicing, and others. In this review, we discuss possible mechanisms of action and role of phosphorylation in the assembly of client complexes by the PAQosome as well as its potential role in cancer, ciliogenesis and ciliopathies.

PDRG1 at the interface between intermediary metabolism and oncogenesis

PDRG1 is a small oncogenic protein of 133 residues. In normal human tissues, the p53 and DNA damage-regulated gene 1 (PDRG1) gene exhibits maximal expression in the testis and minimal levels in the liver. Increased expression has been detected in several tumor cells and in response to genotoxic stress. High-throughput studies identified the PDRG1 protein in a variety of macromolecular complexes involved in processes that are altered in cancer cells. For example, this oncogene has been found as part of the RNA polymerase II complex, the splicing machinery and nutrient sensing machinery, although its role in these complexes remains unclear. More recently, the PDRG1 protein was found as an interaction target for the catalytic subunits of methionine adenosyltransferases. These enzymes synthesize S-adenosylmethionine, the methyl donor for, among others, epigenetic methylations that occur on the DNA and histones. In fact, downregulation of S-adenosylmethionine synthesis is the first functional effect directly ascribed to PDRG1. The existence of global DNA hypomethylation, together with increased PDRG1 expression, in many tumor cells highlights the importance of this interaction as one of the putative underlying causes for cell transformation. Here, we will review the accumulated knowledge on this oncogene, emphasizing the numerous aspects that remain to be explored.

Molecular cloning, characterization and expression analysis of a novel PDRG1 gene from black tiger shrimp (Penaeus monodon)

P53 And DNA Damage-Regulated Gene 1 (PDRG1) is a novel gene which plays an important role in chaperone-mediated protein folding. In the present study, the full-length complementary DNA (cDNA) sequence of the PDRG1 gene from Penaeus monodon (PmPDRG1) was cloned by the rapid amplification of cDNA ends (RACE) method. The cDNA of PmPDRG1 spans 1,613 bp, interrupted by only one short intron, and encodes a protein of 136 amino acids with calculated molecular weight of 15.49 kDa. The temporal expression profile of PmPDRG1 in different tissues and in different developmental stages of the ovary was investigated by real-time quantitative PCR (RT-qPCR). An RNA interference (RNAi) experiment was performed to study the relationship between P. monodon p53 (Pmp53) and PmPDRG1, and the results showed that the relative expression level of PmPDRG1 mRNA was notably up-regulated from 12 h to 96 h after Pmp53 was silenced both in ovary and hepatopancreas. To further explore the role of PmPDRG1 in ovarian development, dopamine (DA) and 5-hydroxytryptamine (5-HT)-injected shrimps were analyzed by RT-qPCR, indicating that PmPDRG1 may be involved in the regulation of ovarian development of P. monodon.

Oleuropein enhances radiation sensitivity of nasopharyngeal carcinoma by downregulating PDRG1 through HIF1α-repressed microRNA-519d

Background

Oleuropein (OL) is a well-known anti-oxidative agent and is shown to reduce the hypoxia-inducible factor 1 α (HIF1α) protein expression after radiation. The current study investigated the effects of OL on radiation response in nasopharyngeal carcinoma (NPC).

Methods

Colony formation assay was performed to compare the radiation response in vitro. Xenograft mouse model was used to study the OL effects on radiation in vivo. Chromatin immunoprecipitation and luciferase reporter assays were performed to identify the relations among HIF1α, miR-519d and PDRG1. Stable HIF1α or PDRG1 overexpression, and miR-519d downregulation were performed to test the radiation response both in vitro and in vivo.

Results

OL strongly enhanced radiosensitivity of NPC cells both in vitro and in vivo. Chromatin immunoprecipitation and luciferase reporter assays suggested miR-519d was a direct target of HIF1α, and PDRG1 was a direct target of miR-519d. Overexpression of HIF1α or PDRG1, and downregulation of miR-519d abolished the radiation sensitizing effects of OL.

Conclusion

Our study hereby demonstrates OL is a radiation sensitizing agent in NPC both in vivo and in vitro. OL treatment reduces the activity of HIF1α-miR-519d-PDRG1 pathway, which is essential to the radiosensitizing effects of OL.

The PDRG1 is an oncogene in lung cancer cells, promoting radioresistance via the ATM-P53 signaling pathway

PDRG1, is short for P53 and DNA damage-regulated gene, which have been found over 10 years. Although severe studies have described the roles of PDRG1 separately in many kinds of tumors, how to act as an oncogene are unclear. To better verify the function of PDRG1 in lung cancer, both loss-function and gain-function of PDRG1 studies based on two human lung cancer lines were performed. Following the transfection of PDRG1, both A549 and 95-D cells showed significant changes in cell viability, the expression of some protein and apoptosis, which were all implied the PDRG1 is an oncogene. Another interesting finding is PDRG1 could promote radioresistance involved the ATM-p53 signaling pathway in lung cancer. If we combine radiotherapy with gene-targeted therapy together effectively, predominant effect may be acquired, which is a huge milestone in clinical cure about lung cancer.

The Oncogene PDRG1 Is an Interaction Target of Methionine Adenosyltransferases

Methionine adenosyltransferases MAT I and MAT III (encoded by Mat1a) catalyze S-adenosylmethionine synthesis in normal liver. Major hepatic diseases concur with reduced levels of this essential methyl donor, which are primarily due to an expression switch from Mat1a towards Mat2a. Additional changes in the association state and even in subcellular localization of these isoenzymes are also detected. All these alterations result in a reduced content of the moderate (MAT I) and high Vmax (MAT III) isoenzymes, whereas the low Vmax (MAT II) isoenzyme increases and nuclear accumulation of MAT I is observed. These changes derive in a reduced availability of cytoplasmic S-adenosylmethionine, together with an effort to meet its needs in the nucleus of damaged cells, rendering enhanced levels of certain epigenetic modifications. In this context, the putative role of protein-protein interactions in the control of S-adenosylmethionine synthesis has been scarcely studied. Using yeast two hybrid and a rat liver library we identified PDRG1 as an interaction target for MATα1 (catalytic subunit of MAT I and MAT III), further confirmation being obtained by immunoprecipitation and pull-down assays. Nuclear MATα interacts physically and functionally with the PDRG1 oncogene, resulting in reduced DNA methylation levels. Increased Pdrg1 expression is detected in acute liver injury and hepatoma cells, together with decreased Mat1a expression and nuclear accumulation of MATα1. Silencing of Pdrg1 expression in hepatoma cells alters their steady-state expression profile on microarrays, downregulating genes associated with tumor progression according to GO pathway analysis. Altogether, the results unveil the role of PDRG1 in the control of the nuclear methylation status through methionine adenosyltransferase binding and its putative collaboration in the progression of hepatic diseases.

The Role of Cdkn1A-Interacting Zinc Finger Protein 1 (CIZ1) in DNA Replication and Pathophysiology

Cdkn1A-interacting zinc finger protein 1 (CIZ1) was first identified in a yeast-2-hybrid system searching for interacting proteins of CDK2 inhibitor p21^Cip1/Waf1. Ciz1 also binds to CDK2, cyclin A, cyclin E, CDC6, PCNA, TCF4 and estrogen receptor-α. Recent studies reveal numerous biological functions of CIZ1 in DNA replication, cell proliferation, and differentiation. In addition, splicing variants of CIZ1 mRNA is associated with a variety of cancers and Alzheimer’s disease, and mutations of the CIZ1 gene lead to cervical dystonia. CIZ1 expression is increased in cancers and rheumatoid arthritis. In this review, we will summarize the biological functions and molecular mechanisms of CIZ1 in these physiological and pathological processes.

Analysis of plasma MicroRNAs to identifying early diagnostic molecule for gastric cancer

Gastric cancer (GC) remains the second leading cause of cancer-related death worldwide. Owing to the lack of early diagnostic techniques, GC is often diagnosed at advanced stage and that leading to low survival rate. Growing evidences have been suggesting that circulating microRNAs play an important role in earlier diagnostic of disease. In the present study, we analyze the circulating miRNAs expression in plasma of volunteers with/without GC aiming to identifying early diagnostic biomarkers. Plasma samples were collected form 6 volunteers including 3 early patients with GC and 3 healthy adults. And then miRNAs microarrays were performed to detect the expression profile of miRNAs in these plasma samples. For further validate the results from miRNAs microarray, qRT-PCR was performed. Finally, target genes of miRNAs were predicted by bioinformatic means. Compared to control plasma, 11 up-regulated and 13 down-regulated miRNAs were detected in the plasma from earlier patients with GC (fold change ≥ 2, P < 0.05). Then, 5 differential expression miRNAs (miR-223, miR-19b-2*, miR-194*, miR-141, miR-1233) were chose to confirm by qRT-PCR. The result is nearly consistent with previous data from miRNAs microarray. Finally, 53 target genes of the 5 miRNAs are predicted by bioinformatics. These differential expression miRNAs may be used as biomarker candidates for minimally invasive diagnosis of early patients with GC in the future.

MicroRNA-214 suppresses oncogenesis and exerts impact on prognosis by targeting PDRG1 in bladder cancer

MicroRNA-214 (miR-214) has been reported to be dysregulated in human bladder cancer tissues. We aimed to investigate the clinical correlation, biological significance and molecular network of miR-214 in bladder cancer. Our results showed miR-214 was down-regulated in bladder cancer tissues and significantly associated with tumor stage, lymph node status, grade, multifocality, history of non-muscle-invasive bladder cancer (NMIBC). Moreover, miR-214 could serve as an independent factor of recurrence-free survival (RFS) and overall survival (OS) for patients with muscle-invasive bladder cancer (MIBC). Restoration of miR-214 expression in bladder cancer cell lines inhibited cell proliferation, migration, invasion and markedly promoted apoptosis. Dual-luciferase reporter assay recognized PDRG1 as direct downstream target gene of miR-214. PDRG1 was significantly increased in tumors low of miR-214 and knockdown of PDRG1 mimicked the effects of miR-214 overexpression. Our findings manifest that miR-214 could exert tumor-suppressive effects in bladder cancer by directly down-regulating oncogene PDRG1 and suggest an appealing novel indicator for prognostic and therapeutic intervention of bladder cancer.

Ciz1 is a novel predictor of survival in human colon cancer

Cip1-interacting zinc-finger protein1 (Ciz1) is a nuclear matrix protein associated DNA replication factor which has been implicated in breast and lung cancer progression. However, the clinical significance of Ciz1 expression in colon cancer has not been determined. This study aimed to examine Ciz1 expression pattern and its potential as a biomarker of prognosis in colon cancer. Using quantitative PCR, tissue microarray (TMA), and ELISA, we evaluated Ciz1 mRNA and protein levels in tumor tissues from patients with colon cancer and in paired adjacent normal tissues. Ciz1 mRNA expression was significantly upregulated in 22 of 39 paired samples (P < 0.001). Immunohistochemistry on TMA-containing samples from 203 colon cancer patients indicated that Ciz1 protein expression was significantly higher in tumor tissues than in adjacent normal tissues (Stuart-Maxwell test, P < 0.001). Elevated expression of Ciz1 protein was significantly correlated with T stage (P < 0.001), N stage (P = 0.005), M stage (P = 0.021), and AJCC stage (P = 0.002). Multivariate Cox proportion hazard model analysis revealed that Ciz1 expression is an independent prognostic factor for overall time (OS; hazard ratio (HR): 1.76; 95% confidence interval (CI): 1.04-2.98; P = 0.034) and disease-free survival (DFS; HR: 2.02; 95% CI: 1.14-3.58; P = 0.017) of patients with colon cancer after colectomy. Our data suggested that Ciz1 may be involved in colon cancer progression and could serve as a novel predictor of survival for colon cancer patients.

Analysis of URI nuclear interaction with RPB5 and components of the R2TP/prefoldin-like complex

Unconventional prefoldin RPB5 Interactor (URI) was identified as a transcriptional repressor that binds RNA polymerase II (pol II) through interaction with the RPB5/POLR2E subunit. Despite the fact that many other proteins involved in transcription regulation have been shown to interact with URI, its nuclear function still remains elusive. Previous mass spectrometry analyses reported that URI is part of a novel protein complex called R2TP/prefoldin-like complex responsible for the cytoplasmic assembly of RNA polymerase II. We performed a mass spectrometry (MS)-based proteomic analysis to identify nuclear proteins interacting with URI in prostate cells. We identified all the components of the R2TP/prefoldin-like complex as nuclear URI interactors and we showed that URI binds and regulates RPB5 protein stability and transcription. Moreover, we validated the interaction of URI to the P53 and DNA damage-Regulated Gene 1 (PDRG1) and show that PDRG1 protein is also stabilized by URI binding. We present data demonstrating that URI nuclear/cytoplasmic shuttling is affected by compounds that stall pol II on the DNA (α-amanitin and actinomycin-D) and by leptomycin B, an inhibitor of the CRM1 exportin that mediates the nuclear export of pol II subunits. These data suggest that URI, and probably the entire R2TP/prefoldin-like complex is exported from the nucleus through CRM1. Finally we identified putative URI sites of phosphorylation and acetylation and confirmed URI sites of post-transcriptional modification identified in previous large-scale analyses the importance of which is largely unknown. However URI post-transcriptional modification was shown to be essential for URI function and therefore characterization of novel sites of URI modification will be important to the understanding of URI function.

Gene expression profiles of tumor regression grade in locally advanced rectal cancer after neoadjuvant chemoradiotherapy

Tumor regression grading (TRG) reportedly has prognostic value in rectal cancer patients after pre-operative chemoradiotherapy (CRT). The aim of this retrospective study was to differentiate gene expression profiles based on TRG in residual cancer cells after CRT. We evaluated pathological response using the criteria of four TRG systems: the Japanese Society for the Cancer of Colon and Rectum (JSCCR), Mandard, Dworak and Rödel. Total RNA was obtained using microdissection from 52 locally advanced rectal cancer specimens from patients who underwent pre-operative CRT to examine the expression levels of 20 genes [PCNA, MKI67, CDKN1A (p21Cip1), CDK2, CHEK1, PDRG1, LGR5, PROM1 (CD133), CD44, SOX2, POU5F1 (OCT4), LKB1, VEGF, EGFR, HGF, MET, HIF1, GLUT1, BAX and BCL2] using real-time quantitative RT-PCR. Gene expression was compared across the four TRG systems. LGR5 gene expression levels in CRT non-responders were significantly higher than in responders in all four grading systems. Patients with elevated PDRG1 and GLUT1 gene expression had poor pathological response in three TRG systems (JSCCR, Dworak and Rödel). MKI67 gene expression in non-responders was significantly higher than in responders in two grading systems (JSCCR and Rödel). While, BAX gene expression in responders was significantly higher than in non-responders in the Mandard TRG system. The results of this study suggest that TRG may reflect characteristics, such as proliferative activity, stemness potency and resistance to hypoxia, of residual cancer cells following pre-operative CRT.

Paternal benzo[a]pyrene exposure affects gene expression in the early developing mouse embryo

The health of the offspring depends on the genetic constitution of the parental germ cells. The paternal genome appears to be important; e.g., de novo mutations in some genes seem to arise mostly from the father, whereas epigenetic modifications of DNA and histones are frequent in the paternal gonads. Environmental contaminants which may affect the integrity of the germ cells comprise the polycyclic aromatic hydrocarbon, benzo[a]pyrene (B[a]P). B[a]P has received much attention due to its ubiquitous distribution, its carcinogenic and mutagenic potential, and also effects on reproduction. We conducted an in vitro fertilization (IVF) experiment using sperm cells from B[a]P-exposed male mice to study effects of paternal B[a]P exposure on early gene expression in the developing mouse embryo. Male mice were exposed to a single acute dose of B[a]P (150mg/kg, ip) 4 days prior to isolation of cauda sperm, followed by IVF of oocytes from unexposed superovulated mice. Gene expression in fertilized zygotes/embryos was determined using reverse transcription-qPCR at the 1-, 2-, 4-, 8-, and blastocyst cell stages of embryo development. We found that paternal B[a]P exposure altered the expression of numerous genes in the developing embryo especially at the blastocyst stage. Some genes were also affected at earlier developmental stages. Embryonic gene expression studies seem useful to identify perturbations of signaling pathways resulting from exposure to contaminants, and can be used to address mechanisms of paternal effects on embryo development.