Human P53 Gene Research Articles

Computational analysis uncovers the deleterious SNPs along with the mutational spectrum of p53 gene and its differential expression pattern in pan-cancer

BackgroundA variety of accessible data, including those of single-nucleotide polymorphisms (SNPs) on the human p53 gene, are made widely available on a global scale. Owing to this, our investigation aimed to deal with the detrimental SNPs in the p53 gene by executing various valid computational tools, including—Filter, SIFT, PredictSNP, Fathmm, UTRScan, ConSurf, SWISS-MODEL, Amber 16 package, Tm-Adjust, I-Mutant, Task Seek, GEPIA2 after practical and basic appraisal, dissolvable openness, atomic progression, analyzing the energy minimization and assessing the gene expression pattern.ResultsOut of the total 581 p53 SNPs, 420 SNPs were found to be missense or non-synonymous, 435 SNPs were in the three prime UTR, and 112 SNPs were in the five prime UTR from which 16 non-synonymous SNPs (nsSNPs) were predicted to be non-tolerable while PredictSNP package predicted 14. Concentrating on six bioinformatics tools of various dimensions, a combined output was generated, where 14 nsSNPs could exert a deleterious effect. We found 5 missense SNPs in the DNA binding domain's three crucial amino acid positions, using diverse SNP analyzing tools. The underlying discoveries were fortified by microsecond molecular dynamics (MD) simulations, TM-align, I-Mutant, and Project HOPE. The ExPASy-PROSITE tools characterized whether the mutations were located in the functional part of the protein or not. This study provides a decisive outcome, concluding the accessible SNPs' information by recognizing the five unfavorable nsSNPs—rs28934573 (S241F), rs11540652 (R248Q), rs121913342 (R248W), rs121913343 (R273C), and rs28934576 (R273H). By utilizing Heatmapper and GEPIA2, several visualization plots, including heat maps, box plots, and survival plots, were produced.ConclusionsThese plots disclosed differential expression patterns of the p53 gene in humans. The investigation focused on recognizing the detrimental nsSNPs, which augmented the danger posed by various oncogenesis in patients of different populations, including within the genome-wide studies (GWS).

Efficient Generation of P53 Biallelic Mutations in Diannan Miniature Pigs Using RNA-Guided Base Editing.

The base editing 3 (BE3) system, a single-base gene editing technology developed using CRISPR/Cas9n, has a broad range of applications for human disease model construction and gene therapy, as it is highly efficient, accurate, and non-destructive. P53 mutations are present in more than 50% of human malignancies. Due to the similarities between humans and pigs at the molecular level, pig models carrying P53 mutations can be used to research the mechanism of tumorigenesis and improve tumor diagnosis and treatment. According to pathogenic mutations of the human P53 gene at W146* and Q100*, sgRNAs were designed to target exon 4 and exon 5 of the porcine P53 gene. The target editing efficiencies of the two sgRNAs were 61.9% and 50.0%, respectively. The editing efficiency of the BE3 system was highest (about 60%) when C (or G) was at the 5th base. Puromycin screening revealed that 75.0% (21/28) and 68.7% (22/32) of cell colonies contained a P53 mutation at sgRNA-Exon5 and sgRNA-Exon4, respectively. The reconstructed embryos from sgRNA-Exon5-5# were transferred into six recipient gilts, all of which aborted. The reconstructed embryos from sgRNA-Exon4-7# were transferred into 6 recipient gilts, 3 of which became pregnant, resulting in 14 live and 3 dead piglets. Sequencing analyses of the target site confirmed 1 P53 monoallelic mutation and 16 biallelic mutations. The qPCR analysis showed that the P53 mRNA expression level was significantly decreased in different tissues of the P53 mutant piglets (p < 0.05). Additionally, confocal microscopy and western blot analysis revealed an absence of P53 expression in the P53 mutant fibroblasts, livers, and lung tissues. In conclusion, a porcine cancer model with a P53 point mutation can be obtained via the BE3 system and somatic cell nuclear transfer (SCNT).

Fullerenol as a photoelectrochemical nanoprobe for discrimination and ultrasensitive detection of amplification-free single-stranded DNA

Traditional approaches for nucleic acids detection require prior amplification of target genes, while nanomaterials-aided DNA biosensors are very magnificent but still suffer from the nanomaterial acquirement and limited sensitivity (above picomolar level). Herein, fullerenol C60(OH)25, a representative fullerene derivative, was employed as a photoelectrochemical (PEC) nanoprobe to achieve discrimination and ultrasensitive detection of amplification-free single-stranded DNA (ssDNA) down to sub-femtomolar level. The bonded hydroxyl groups with intense density endowed fullerenol to directly recognize and capture ssDNA-AuNPs via the hydrogen bonding interactions (H-bonds), leading to a sharply decreased photocurrent with quenching efficiency up to 85%, which could be attributed to the photo-generated electrons on the conduction band of fullerenol (−4.66 eV) preferentially migrating to the Fermi level of AuNPs (−5.1 eV) rather than the electrode. In the presence of target gene (mutant human p53 gene fragment), the H-bonds between fullerenol and ssDNA were competitively depleted during the base pairing process of complete hybridization between ssDNA and target, making double-stranded DNA-AuNPs (dsDNA-AuNPs) depart so that the photocurrent powerfully recovered. On basis of the photocurrent variation before and after target introduction, this proposed simple, rapid and ultrasensitive PEC biosensor for amplification-free target gene detection illustrated a wide liner ranged from 1 fM to 100 pM and a detection limit of 0.338 fM. This work presented an ingenious strategy for the discrimination and ultrasensitive detection of nucleic acids, and the well-designed PEC biosensor was further conducive to the impetus of clinic diagnostics.

Abstract 3548: Differential miRNA expression levels and risk of lung adenocarcinoma in transgenic mice

Abstract In 2018, 154,100 lung cancer deaths are projected to occur in the United States. Currently, there are very few predictors to identify lung cancer in its early stages. Recent studies have demonstrated a link between microRNAs (miRNAs) and specific cancers. Dysregulation of miRNAs in cancer can lead to upregulate oncogenes and downregulate tumor suppressors. Previously, we developed a line of transgenic mice expressing the human mutant p53 (273H) gene. The transgenic mice were observed to have accelerated risk of spontaneous adenocarcinomas at the age of 13-14 months. However the mechanisms involved in lung tumorigenesis at this age cohort is still unclear. Herein, we report our analysis on miRNA expression in lung tissue between a low risk cohort and high risk cohort. To investigate the role of mutant p53 in lung tumorigenesis, a p53(273H) transgenic mouse model was developed. Murine lung tissue were harvested from age groups of 7 months (low risk group with risk of 5% of lung cancer), and the 13.5 months (high risk group with risk of 27% of lung cancer). RNA was then extracted with trizol, and miRNAs were quantified using a Nanostring counter miRNA array. The miRNA expressions were normalized and averaged. The normalized miRNAs from high risk group (n=3) were compared with the miRNAs obtained from the low risk group (n=3). We screened 600 different miRNA expressions from these age cohorts. Total of 19 miRNAs that had an up-regulation of at least 5-fold in the high risk cohort as compared with the low risk cohort including some important miRNAs in human lung cancer (e.g mmu-miR-2133, mmu-miR-2140, mmu-miR-142-5p, mmu-miR-2138, mmu-miR-2134, mmu-miR-2135, mmu-miR-452, mmu-miR-703, mmu-miR-690, mmu-miR-206, mmu-miR-706, mmu-miR-691, mmu-miR-208a, mmu-miR-574-5p, mmu-miR-1). Four miRNAs had a down regulation at least 5-fold in the high risk cohort including mmu-miR-720, mmu-miR-1937c, and mmu-miR-1937a+mmu-miR-1937b.We found a group of microRNAs to be expressed abnormally high and another group microRNA to be expressed abnormally low in the high risk group as comparing to the low risk group. We compared the data to our murine lung cancer microRNA profile and found a group of miRNA expression potentially correlated to risk of lung cancer development in mice. Most human lung cancers are at an advanced stage when they are first found. These cancers are very hard to cure. However, if a lung cancer is found at an earlier stage when it is small and before it has spread, the early stage lung cancer can be successfully treated. Further studies are necessary to employ these miRNAs as early diagnostic biomarkers in prediction of human lung cancers. Citation Format: Myia Aiges, Abeer Almiman, Li Gao, Kathleen Dotts, Miguel A. Villalona-Calero, Wenrui Duan. Differential miRNA expression levels and risk of lung adenocarcinoma in transgenic mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3548.

인체 대장암 세포주 HCT 116와 HT-29에서 아팝토시스 세포사멸과 자가소화작용의 이중유도에 의한 녹나무 에탄올 추출물의 mTOR 신호경로를 통한 항암효과

Cinnamomum camphora is known as a tree that has been used in traditional medicine and food. However, its biological activities in cancer have not yet been clearly investigated. In this study, we investigate the anti-cancer effects of ethanol extract of Cinnamomum camphora on two kinds of human colon cancer cell lines (HCT 116 and HT-29). In previous study, about 50% of cancer cells have p53 mutations. Therefore, two kinds of cancer cells with different p53 gene mutation status are able to verify the effects of cancer more accurately. it is conducted several experiments to prove the effects of anti-cancer through apoptosis and autophagy. It is confirmed the anti-proliferative activity of Cinnamomum camphora ethanol extract through WST-1 assay. Cancer cell migration rate is detected by cell invasion assay and scratched wound healing assay. Also, the expression of apoptosis and autophagy related proteins are assessed by western blot. Our data reveal that Cinnamomum camphora ethanol extract inhibits the cancer cell growth of both p53 gene wild type HCT 116 human colon cancer cells and p53 gene mutation type HT-29 human colon cancer cells. Moreover, it confirms that CCD841 Human colon normal cells are not affected by Cinnamomum camphora ethanol extract. Cinnamomum camphora ethanol extract regulated expression of apoptotic and autophagic proteins in both cancer cells. Then, it is demonstrated that apoptosis and autophagy are induced through the mTOR pathway when treated with rapamycin (mTOR inhibitor). Taken together, these results show that Cinnamomum camphora ethanol extract has considerable potential as chemotherapeutic substance.

P53 and its isoforms in DNA double-stranded break repair.

DNA double-stranded break (DSB) is one of the most catastrophic damages of genotoxic insult. Inappropriate repair of DNA DSBs results in the loss of genetic information, mutation, and the generation of harmful genomic rearrangements, which predisposes an organism to immunodeficiency, neurological damage, and cancer. The tumor repressor p53 plays a key role in DNA damage response, and has been found to be mutated in 50% of human cancer. p53, p63, and p73 are three members of the p53 gene family. Recent discoveries have shown that human p53 gene encodes at least 12 isoforms. Different p53 members and isoforms play various roles in orchestrating DNA damage response to maintain genomic integrity. This review briefly explores the functions of p53 and its isoforms in DNA DSB repair.

Exploring the binding mechanism of saccharin and sodium saccharin to promoter of human p53 gene by theoretical and experimental methods

In the past few decades, extensive discussions have been on the impact of artificial sweeteners on the risk of cancer. The present study aimed to evaluate the interaction of saccharin (SA) and sodium saccharin (SSA) with the promoter of the human p53 gene. The binding ability was assessed using the spectroscopic technique, molecular docking and molecular dynamics (MD) simulation methods. Free energy of binding has been calculated using Molecular Mechanics/Poisson–Boltzmann Surface Area (MM/PBSA) method. Fluorescence spectra of mentioned gene with concentration profiles of SA and SSA were obtained in a physiological condition. A gradual increase without any significant spectral shift in the fluorescence intensity of around 350 nm was evident, indicating the presence of an interaction between both compounds and gene. The docking results showed that both compounds were susceptible to bind to 5′-DG56DG57-3′ nucleotide sequence of gene. Furthermore, the MD simulation demonstrated that the binding positions for SA and SSA were 5′-A1T3T4-3′ and 5′-G44T45-3′ sequences of gene, respectively. The binding of these sweeteners to gene made significant conformational changes to the DNA structure. Hydrogen and hydrophobic interactions are the major forces in complexes stability. Through the groove binding mode, the non-interactive DNA-binding nature of SSA and SA has been demonstrated by the results of spectrofluorometric and molecular modeling. This study could provide valuable insight into the binding mechanism of SA and its salt with p53 gene promoter as macromolecule at the molecular level in atomistic details. This work can contribute to the possibility of the potential hazard of carcinogenicity of this sweetener and to design and apply new and safer artificial sweeteners.AbbreviationsSASaccharinSSASodium SaccharinPp53gpromoter of human p53 geneMDMolecular dynamicsRMSDRoot-mean-square deviationRMSFRoot-mean-square fluctuationRgRadius of GyrationSASASolvent-Accessible Surface AreaADIAcceptable daily intakeMM/PBSAMolecular Mechanics/Poisson–Boltzmann Surface AreaCommunicated by Ramaswamy H. Sarma

Ultrasound-guided intertumoral injection of contrast agents combined with human p53 gene for the treatment of breast cancer

The objective of this study was to investigate the effects of ultrasound-guided injection of ultrasound contrast agents (UCAs) and the p53 gene on the treatment of rats with breast cancer (BC). Assembly of the p53 expression vector as well as that of a rat model with BC consisted of 200 successfully modeled rats randomly divided into 5 groups: p53 gene introduction, p53 gene introduction + ultrasound irradiation, p53 gene introduction + UCAs, p53 gene introduction + UCA + ultrasound irradiation, and UCA + ultrasound irradiation groups. Expression of p53 was detected via quantitative real-time polymerase chain reaction (qRT-PCR), western blotting and immunohistochemical staining. In the p53 gene introduction + ultrasound irradiation group, we observed increased tumor volume with blood flow signals around and necrotic tumor tissues with an inhibition rate of 36.30%, as well as higher expression of p53 than that in the p53 gene introduction group and p53 gene introduction + UCA group. In the p53 gene introduction + UCA + ultrasound irradiation group, tumor volume increased slightly with reduced blood flow signals and massive degenerative necrosis of tumor cells was identified with inhibition rate of 62.62%, and expression of p53 was higher than that in the rest groups. Taken together, the key findings obtained from the present study elucidate that injection of p53 gene and UCA microbubbles guided by ultrasound could increase the expression of p53, thus inhibiting the tumor growth in rats with BC.

Studying The Expression of Human P53 Gene in Patients Carrying Breast Cancer.

The gene P53 can activate DNA repair proteins when DNA has sustained damage. So, it is an important factor in aging. Also, P53 gene can also be modified by mutagens (chemicals, radiation, or viruses), increasing the likelihood for uncontrolled cell division. For this importance, we collected thirty samples from Yarmouk hospital in Baghdad, Iraq.&#x0D; Twenty-nine from women patients carrying breast cancer and the last one was from healthy woman, and the samples that we have taken were embedded in paraffin wax. The extracted RNA from each samples was used to check the expression of a suppressor gene (P53) via Real time PCR. We designed primers of P53 gene on encoded sequence (Exon), to make sure generation a specific PCR product of P53 gene by converting mRNA to cDNA then PCR Product. The expression of each samples was fluctuated between 0.1 fold to 0.2 fold compared with the control (the healthy sample). The highest expression showed was samples 7 (0.2 fold), and the lowest expression showed was samples 27 (0.1 fold) that compared with control expression (sample 19). While the control expression was the highest (0.25 fold) among all samples. &#x0D; The results indicate that tumor may affects on a suppressor gene (P53) and can decrease the gene expression, and eventually can decrease the P53 suppressor protein that can be used it in the cell protection against cancer.

Surgery combined with adenoviral p53 gene therapy for treatment of non-small cell lung cancer: a phase II study.

ObjectiveTo assess the efficacy of radical surgery combined with recombinant adenoviral human p53 (rAd-p53) gene therapy in treatment of resectable non-small cell lung cancer.MethodA total of 163 patients with resectable NSCLC meeting the inclusion criteria were randomly assigned to two groups: radical surgery alone (S) and radical surgery plus surgical wound surface injection of 2 x 1012 rAd-p53 units (SP). All patients were followed up for at least 3 years for efficacy and safety. Study endpoints were loco-regional recurrence or distant metastasis (Rec-Met) rate as primary endpoints, and progression free survival (PFS), overall survival (OS) and safety assessments as secondary endpoints.ResultsRecurrence or metastasis (Rec/Met) after surgery were 24/82 (29.27%) in SP group and 37/81 (45.68%) in S group. The difference in the Rec/Met rate was statistically significant (p = 0.0304) by chi-square test. The hazard ratios after adjusting of age and disease stage (S vs. SP) of PFS and OS are 1.772 (95% CI, 1.102 to 2.848) and 2.047 (95% CI, 1.109 to 3.377), respectively. The 3 years PFS and OS for SP vs. S were 71.9% vs. 46.9%, and 88.4% vs. 67.0%, respectively. Differences in PFS and OS between two treatment groups were significant with the p values of 0.0165 and 0.0191, respectively, using Log-Rank test.ConclusionsThe wound surface injection of rAd-p53 showed efficacious effects in preventing recurrence or metastasis and improving PFS and OS after a radical surgery in patients with NSCLC.

Abstract 300: Taeumjowi-tang (TJ001) induces G2/M cell cycle arrest but not apoptosis in p53-mutant prostate cancer via up-regulation of p21WAF/CIP1

Abstract Taeumjowi-tang (TJ001) is a traditional Korean medicine that usually prescribed for Tae-um person to regulate stomach-related symptoms including headache, indigestion, and jaundice. Other studies on anti-obesity effect of TJ001 have also been researched, but have never been reported as a cure for cancer. In the present study, we investigated the molecular mechanism that TJ001 induces G2/M cell cycle arrest in DU145 (p53-mutant) prostate cancer cells. The missense mutation in human p53 gene (TP53) confers oncological effect to tumor suppressor p53-mutant protein. In prostate cancer, this gain-of-function of p53-mutant is associated with androgen-independence, increased angiogenesis, and metastasis. Our in vitro studies showed that a water extract of TJ001 induced G2/M cell cycle arrest via p53-mutant status and p21WAF/CIP1 up-regulation. Conventinally, p21WAF/CIP1 is induced by mediating p53 regulation, but, in experiments, handling the p53-dependent and -independent pathway. Although serine15-phosphorylated p53 and p53 proteins remained unchanged, p21WAF/CIP1 expression is induced and cyclin B1/Cdc2 complex is inactivated by a decrease of cyclin B1. In addition, in p53-independent pathway, the level of Cdc25C expression decreased and Serine-216 phosphorylated Cdc25C increased. Generally, concomitant with G2/M cell cycle arrest come the apoptosis cell death, but in the study, prolonged G2/M cell cycle arrest developed not apoptosis but cell senescence. Therefore, our data suggest that TJ001 is helpful for p53-mutant prostate cancer treatment. Citation Format: Soo-Yeon Kang, Hyo In Kim, Se Hyang Hong, Jin Mo Ku, Kangwook Lee, Myeong-Sun Kim, Yu-jeong Choi, Chunhoo Cheon, Youme Ko, Ching Wen Huang, Yui Sasaki, Sohyeon Kang, Hye-Sook Seo, Tai Young Kim, Ji Hye Kim, Yong Cheol Shin, Seong-Gyu Ko. Taeumjowi-tang (TJ001) induces G2/M cell cycle arrest but not apoptosis in p53-mutant prostate cancer via up-regulation of p21WAF/CIP1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 300. doi:10.1158/1538-7445.AM2017-300

Abstract 3417: The impact of p53 codon 72 SNP upon aging and longevity in mouse models

Abstract p53 has dual functions on longevity. p53 plays a crucial role in tumor suppression to prevent early death due to cancer. However, it has been suggested by animal models that constitutively increased p53 activity accelerates the decline of stem/progenitor cells’ self-renewal function during aging process, which leads to a reduced lifespan. In humans, the role of p53 in aging and longevity has not been well established. As a haplo-insufficient gene, p53 is under the tight regulation in cells. Attenuation of p53 function contributes greatly to tumorigenesis. p53 codon 72 single nucleotide polymorphism (SNP) with either an arginine (R72) or a proline (P72) at codon 72 is a naturally occurring common SNP that can influence the activity of p53. The P72 allele is weaker than the R72 allele in inducing apoptosis and suppressing cellular transformation. Individuals with the P72 allele have increased cancer risk compared to the R72 allele. However, it is unclear whether the change of p53 activity in humans by functional SNPs could impact upon longevity. A perspective study with an aging human population showed that P72 allele is associated with longer survival despite its increased risk for cancer development. These findings strongly suggest that p53 activity is reversely associated with aging, and SNPs in the p53 pathway could impact upon the life span in humans. In this study, we employed a mouse model system with knock-in of human p53 gene (Hupki) carrying either R72 or P72 SNP to investigate the impact of p53 codon 72 SNP upon longevity and its underlying mechanism. Mice with p53 P72 allele showed weaker transcriptional activity than the R72 allele toward a subset of p53 target gene, suggesting that these mice retain the function of p53 codon 72 SNP in human. We found that although mice with p53 P72 have increased cancer risk compared to mice with p53 R72, mice with p53 P72 that escaped tumor development showed longer lifespan compared to mice with p53 R72 that do not develop tumor. Mice with p53 P72 displayed a delay in aging process compared to mice with p53 R72; mice with p53 P72 have slower reduction in bone density, dermal thickness and wound healing ability during aging process. We compared the effects of p53 codon 72 SNPs on stem cell population and function as a possible mechanism that contributes to their difference in longevity. Compared to mice with p53 R72, mice with p53 P72 allele have lower number of long-term stem/progenitor cells and better self-renewal function during aging process. Consistently, aging mice with p53 P72 allele exhibited better long-term stem cell ability of engraftment and repopulation than aging mice with p53 R72 allele as evaluated by bone marrow transplantation assay. Taken together, results from this study demonstrate that p53 codon 72 SNP has a direct impact on aging and longevity, and strongly support the role of p53 in regulation of stem/progenitor cells’ function and longevity. Citation Format: Yuhan Zhao, Lihua Wu, Xuetian Yue, Cen Zhang, Jun Li, Jianming Wang, Zhaohui Feng, Wenwei Hu. The impact of p53 codon 72 SNP upon aging and longevity in mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3417. doi:10.1158/1538-7445.AM2017-3417

Alternative Splicing in the Cytochrome P450 Superfamily Expands Protein Diversity to Augment Gene Function and Redirect Human Drug Metabolism.

The human genome encodes 57 cytochrome P450 genes, whose enzyme products metabolize hundreds of drugs, thousands of xenobiotics, and unknown numbers of endogenous compounds, including steroids, retinoids, and eicosanoids. Indeed, P450 genes are the first line of defense against daily environmental chemical challenges in a manner that parallels the immune system. Several National Institutes of Health databases, including PubMed, AceView, and Ensembl, were queried to establish a comprehensive analysis of the full human P450 transcriptome. This review describes a remarkable diversification of the 57 human P450 genes, which may be alternatively processed into nearly 1000 distinct mRNA transcripts to shape an individual's P450 proteome. Important P450 splice variants from families 1A, 1B, 2C, 2D, 3A, 4F, 19A, and 24A have now been documented, with some displaying alternative subcellular distribution or catalytic function directly linked to a disease pathology. The expansion of P450 transcript diversity involves tissue-specific splicing factors, transformation-sensitive alternate splicing, trans-splicing between gene transcripts, single-nucleotide polymorphisms, and epigenetic regulation of alternate splicing. Homeostatic regulation of variant P450 expression is influenced also by nuclear receptor signaling, suppression of nonsense-mediated decay or premature termination codons, mitochondrial dysfunction, or host infection. This review focuses on emergent aspects of the adaptive gene-splicing process, which when viewed through the lens of P450-nuclear receptor gene interactions, resembles a primitive immune-like system that can rapidly monitor, respond, and diversify to acclimate to fluctuations in endo-xenobiotic exposure. Insights gained from this review should aid future drug discovery and improve therapeutic management of personalized drug regimens.

DNA Binding and Cleavage by the Human Parvovirus B19 NS1 Nuclease Domain

Infection with human parvovirus B19 (B19V) has been associated with a myriad of illnesses, including erythema infectiosum (Fifth disease), hydrops fetalis, arthropathy, hepatitis, and cardiomyopathy, and also possibly the triggering of any number of different autoimmune diseases. B19V NS1 is a multidomain protein that plays a critical role in viral replication, with predicted nuclease, helicase, and gene transactivation activities. Herein, we investigate the biochemical activities of the nuclease domain (residues 2-176) of B19V NS1 (NS1-nuc) in sequence-specific DNA binding of the viral origin of replication sequences, as well as those of promoter sequences, including the viral p6 and the human p21, TNFα, and IL-6 promoters previously identified in NS1-dependent transcriptional transactivation. NS1-nuc was found to bind with high cooperativity and with multiple (five to seven) copies to the NS1 binding elements (NSBE) found in the viral origin of replication and the overlapping viral p6 promoter DNA sequence. NS1-nuc was also found to bind cooperatively with at least three copies to the GC-rich Sp1 binding sites of the human p21 gene promoter. Only weak or nonspecific binding of NS1-nuc to the segments of the TNFα and IL-6 promoters was found. Cleavage of DNA by NS1-nuc occurred at the expected viral sequence (the terminal resolution site), but only in single-stranded DNA, and NS1-nuc was found to covalently attach to the 5' end of the DNA at the cleavage site. Off-target cleavage by NS1-nuc was also identified.

Recombinant Newcastle disease virus expressing P53 demonstrates promising antitumor efficiency in hepatoma model.

BackgroundNumerous studies have demonstrated that the NDV-mediated gene therapy is a promising new approach for treatment of cancers. P53 plays a vital role in tumor suppression and surveillance. Therefore, we hypothesize that a recombinant NDV expressing P53 would be an ideal agent for the hepatoma therapy.ResultsIn the essay, the human P53 gene was incorporated into the genome of a lentogenic strain (named rNDV-P53), which did not affect viral replication kinetics and magnitude in HepG2 cells. Compared to the vehicle virus, rNDV-P53 increased cell growth suppressor ratio and early apoptosis by 2 folds, and decreased the mitochondrial membrane potential in HepG2 cells. In vivo studies, treatment with rNDV-P53 reduced tumor volume of tumor-bearing mice by more than 4 folds, tumor weight by more than 5 folds comparing with rNDV. The 120-day survival rate of rNDV-P53-treated mice was 75 %, survival rate of rNDV-treated mice was 12.5 %. TUNEL analysis showed a significant increase in the apoptosis rate in the tumor tissues of rNDV-P53-treated mice than that of rNDV-treated mice. Moreover, serum chemistries revealed an insignificant change of blood urea nitrogen (BUN), creatinine levels, alanine aminotransferase (ALT) and aspartate transaminase (AST) in rNDV-P53-treated group compared to normal mice, suggesting treatment with the recombinant virus was not toxic.ConclusionrNDV-P53 is a potent candidate for carcinoma therapy especially for hepatocarcinoma.

Cross-triggered and cascaded recycling amplification for ultrasensitive electrochemical sensing of the mutant human p53 gene.

Based on an endonuclease-assisted, cross-triggered and cascaded recycling amplification strategy, the construction of a simple electrochemical sensing platform for the ultrasensitive detection of the mutant p53 gene in human serum is described. Using this new signal amplification approach, the sub-femtomolar level of the mutant p53 gene can be selectively detected.

Low frequency ultrasound combined with microbubbles to promote the transfection of wild-type P53 gene in human prostate cancer cells mediated by liposome

Objective To study low frequency ultrasound combined with microbubbles to promote the transfection of P53 gene in human prostate cancer cells mediated by liposome. Methods Ultrasound equipment was used with a frequency of 21 kHz and intensity was 46 mW/cm2 and the working time was controlled at 20% (i.e., 2 sontime and 8 sofftime) lasting 5 minutes. The human prostate cancer cell line PC-3 suspension was prepared, the cell concentration was adjusted to 1×105 cell/ ml, and cells were divided into 8 groups: control group, single microbubbles group, single ultrasound group, ultrasound combined with microbubbles group, single liposome group, liposome combined with microbubbles group, liposome combined with ultrasound group, liposome combined with ultrasound and microbubbles group. Each microbubbles group was added SonoVue 200 μl and the wild type P53 plasmid, plasmid∶liposome is 1∶2. At 24 hours after irradiation, Western-blot and RT-PCR were used to detect the gene transfection efficiency, CCK-8 was used to detect cell proliferation, then cell survival rate was calculated, cell apoptosis was detected by flow cytometry. Results After transfection, compared with single liposome group and control group, liposomes combined with ultrasound and microbubbles group can significantly improve expression of the human wild type p53 gene and protein (P<0.001). After transfection, the apoptosis rate of human prostate cancer PC-3 cells in liposomes combined with ultrasound and microbubbles group was significantly higher than that of the liposome group and control group (P<0.001). And after transfection, cell survival rate of liposome combined with ultrasound and microbubble group decreased significantly than those of single liposome group and control group (P<0.001). Conclusions Low frequency and low energy ultrasound combined with microbubbles can promote the transfection of human wild-type P53 gene mediated by liposome. Key words: Sonication; Microbubbles; Liposomes; Prostatic neoplasms

Association Between p21 Ser31Arg Polymorphism and Gastrointestinal Tract Tumor Risk

Human p21 gene is characterized by a polymorphism at codon 31 leading to a Serine-to-Arginine (S/R), two different alleles of p21 Ser31Arg (rs 1801270) polymorphism have been shown to differ significantly in their transcriptional efficiency. More and more investigations are now being carried out to examine a possible link between the p21 Ser31Arg polymorphism and cancer. However, the results were inconclusive. Therefore, we carried out a systematic review and meta-analysis to examine whether this polymorphism is associated with gastrointestinal tract tumor in Asian. Seven studies (n = 2690), comprising 967 cases and 1723 controls in Asian population, were included in our study. The meta-analysis showed significant association between Ser-allele or Ser/Ser genotype and the susceptibility to gastrointestinal tract tumor in overall studies (Ser-allele vs. Arg-allele: OR = 1.17, 95% CI: 1.04-1.31; Ser/Ser vs. Arg/Arg: OR = 1.38, 95% CI: 1.09-1.75; Ser/Ser vs. Arg/Ser: OR = 1.27, 95% CI: 1.05-1.53; Ser/Ser vs. Arg/Ser + Arg/Arg: OR = 1.29, 95% CI: 1.07-1.54). Despite the limitations, the results of the present meta-analysis suggested that, in the p21 Ser31Arg polymorphism, Ser-allele and Ser/Ser genotype might be risk factors for gastrointestinal tract tumor in Asian populations.

쌀눈 발아의 최적조건 확립 및 p53 항암 유전자의 발현

Rice embryo is more abundant than endosperms in nutrients such as proteins, lipids, and vitamin B1. In this study, we constructed p53 plasmid that could be expressed in a plant system, and investigated optimal germination conditions in a variety of media. For construction of p53 plasmid, we performed p53 amplification from pCDNA-p53, subcloned to TA cloning vector, and then reconstructed into pGEM-CaMV plant expression vector. On the other hand, we prepared a variety of imbibition buffers and complete media for efficient germination of the rice embryo. Imbibition buffers prepared with different concentrations of salt or detergent showed no significant effect on germination efficiency. We prepared further culture media, such as solid agar, liquid media, and paper towel to establish the optimal conditions. Rice embryo showed germination rates of more than 70% in the solid medium, more than 60% in the paper towel medium, but less than 25% in liquid media, although germination rate did not differ with varying concentrations of salt and sucrose in culture media. Under the optimal germination conditions, we introduced the p53 plasmid using imbibition method, and finally detected human p53 gene expression in the germinated rice embryo. This method might present a novel, practical approach for evaluating efficient gene expression utilizing imbibition method in rice embryo.

Correlation analysis of ultrasonic characteristics, pathological type, and molecular markers of thyroid nodules.

The present study was conducted to analyze the correlation between ultrasonic characteristics, pathological type, and molecular markers of thyroid-tumor-related genes as well as to evaluate the diagnosis and prognosis of thyroid nodules. The acoustic characteristics of 130 thyroid specimens were detected. Pathological sectioning and immunohistochemical detection were performed to determine the correlation between tumor gene expression and ultrasonic characteristics. Ultrasonic testing revealed that malignant nodules were normally accompanied by lymph nodes. Expression of the human telomerase reverse transcriptase, Ki67, vascular endothelial growth factor, Ret, and P53 genes exhibited statistically significant differences in malignant, benign, and normal tissues. The performance of thyroid malignant nodules showed different degrees of correlation with the expression of the human telomerase reverse transcriptase, Ki67, VEGF, Ret, and P53 genes. Color Doppler ultrasound is highly sensitive for thyroid nodules and is therefore effective for identifying thyroid nodules and early diagnosis of thyroid cancer. Color Doppler ultrasound can identify benign or malignant thyroid nodules based on 5 characteristic indicators. Tumor pathology and gene expression are associated with the sonographic features of thyroid cancer. Therefore, determining the pathological basis of ultrasonography would facilitate prognostic assessments of thyroid cancer.