Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world,hepatocellular carcinoma(HCC)is among the top 10 most prevalent malignancies.HCC formation has indeed been linked to numerous etiological factors,including alcohol usage,hepatitis viruses and liver cirrhosis.Among the most prevalent defects in a wide range of tumours,notably HCC,is the silencing of the p53 tumour suppressor gene.The control of the cell cycle and the preservation of gene function are both critically important functions of p53.In order to pinpoint the core mechanisms of HCC and find more efficient treatments,molecular research employing HCC tissues has been the main focus.Stimulated p53 triggers necessary reactions that achieve cell cycle arrest,genetic stability,DNA repair and the elimination of DNA-damaged cells’responses to biological stressors(like oncogenes or DNA damage).To the contrary hand,the oncogene protein of the murine double minute 2(MDM2)is a significant biological inhibitor of p53.MDM2 causes p53 protein degradation,which in turn adversely controls p53 function.Despite carrying wt-p53,the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway.High p53 in-vivo expression might have two clinical impacts on HCC:(1)Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways;and(2)Exogenous p53 makes HCC susceptible to various anticancer drugs.This review describes the functions and primary mechanisms of p53 in pathological mechanism,chemoresistance and therapeutic mechanisms of HCC.

Study of pathogenic genes in a pedigree with familial dilated cardiomyopathy

BACKGROUND Dilated cardiomyopathy(DCM)is a genetically heterogeneous cardiac disorder characterized by left ventricular dilation and contractile dysfunction.The substantial genetic heterogeneity evident in patients with DCM contributes to variable disease severity and complicates overall prognosis,which can be very poor.AIM To identify pathogenic genes in DCM through pedigree analysis.METHODS Our research team identified a patient with DCM in the clinic.Through invest-igation,we found that the family of this patient has a typical DCM pedigree.High-throughput sequencing technology,next-generation sequencing,was used to sequence the whole exomes of seven samples in the pedigree.RESULTS A novel and potentially pathogenic gene mutation-ANK2p.F3067L-was discovered.The mutation was completely consistent with the clinical information for this DCM pedigree.Sanger sequencing was used to further verify the locus of the mutation in pedigree samples.These results were consistent with those of high-throughput sequencing.CONCLUSIONS ANK2p.F3067L is considered a novel and potentially pathogenic gene mutation in DCM.

Changes of p53 and Waf1p21 and cell proliferation in esophageal carcinogenesis

AIM To study the correlationship between the changes of p53, Waf1p21 and the cell proliferation determined by PCNA at different stages of human esophageal carcinogenesis. METHODS Biopsied and resected esophageal tissues from a high risk population for esophageal cancer in northern China were used in this study. All the specimens were fixed with 85% alcohol and further processed with routine histology. The avidin biotin peroxidase complex (ABC) method was used for the detection of p53, Waf1p21 and PCNA. RESULTS The strong nuclear staining for p53, Waf1p21 and PCNA was observed in the normal esophageal epithelium and the epithelia with different severities of lesions. As the lesions progressed to dysplasia (DYS) and to esophageal squamons cell carcinoma (SCC), the percentage of Waf1p21 immunoreactivity decreased. The number of Waf1p21 immunostaining positive cells increased slightly from normal to basal cell hyperplasia (BCH), but there was no further increase in DYS and in SCC. The total number of positive cells for Waf1p21 stain appeared to be lower than that of p53 in normal and BCH esophageal epithelia and much lower in DYS and SCC. The Waf1p21 positive immunostaining cells were located at the third and forth cell layers in half of the samples examined, which was 2～4 cell layers higher than that of PCNA and p53 in the same histological categories of normal, BCH and DYS. CLNCLUSION The low levels of Waf1p21 at the stage of DYS may be related to a functional loss of p53. Other mechanisms may also be responsible to the lack of Waf1p21 expression in DYS and SCC.

Genes for RNA-binding proteins involved in neuralspecific functions and diseases are downregulated in Rubinstein-Taybi iNeurons

Taking advantage of the fast-growing knowledge of RNA-binding proteins(RBPs)we review the signature of downregulated genes for RBPs in the transcriptome of induced pluripotent stem cell neurons(iNeurons)modelling the neurodevelopmental Rubinstein Taybi Syndrome(RSTS)caused by mutations in the genes encoding CBP/p300 acetyltransferases.We discuss top and functionally connected downregulated genes sorted to“RNA processing”and“Ribonucleoprotein complex biogenesis”Gene Ontology clusters.The first set of downregulated RBPs includes members of hnRNHP(A1,A2B1,D,G,H2-H1,MAGOHB,PAPBC),core subunits of U small nuclear ribonucleoproteins and Serine-Arginine splicing regulators families,acting in precursor messenger RNA alternative splicing and processing.Consistent with literature findings on reduced transcript levels of serine/arginine repetitive matrix 4(SRRM4)protein,the main regulator of the neural-specific microexons splicing program upon depletion of Ep300 and Crebbp in mouse neurons,RSTS iNeurons show downregulated genes for proteins impacting this network.We link downregulated genes to neurological disorders including the new HNRNPH1-related intellectual disability syndrome with clinical overlap to RSTS.The set of downregulated genes for Ribosome biogenesis includes several components of ribosomal subunits and nucleolar proteins,such NOP58 and fibrillarin that form complexes with snoRNAs with a central role in guiding post-transcriptional modifications needed for rRNA maturation.These nucleolar proteins are“dual”players as fibrillarin is also required for epigenetic regulation of ribosomal genes and conversely NOP58-associated snoRNA levels are under the control of NOP58 interactor BMAL1,a transcriptional regulator of the circadian rhythm.Additional downregulated genes for“dual specificity”RBPs such as RUVBL1 and METTL1 highlight the links between chromatin and the RBP-ome and the contribution of perturbations in their cross-talk to RSTS.We underline the hub position of CBP/p300 in chromatin regulation,the impact of its defect on neurons’post-transcriptional regulation of gene expression and the potential use of epidrugs in therapeutics of RBP-caused neurodevelopmental disorders.

Study on the Function of ORF Genes of Porcine Circovirus-like Virus P1

[Objectives]This study was conducted to determine the functions of eight ORF genes of porcine circovirus-like virus P1.[Methods]The double-copy tandem molecular cloning of porcine circovirus-like virus P1 genome was used to construct molecular clones with eight ORFs deleted by DNA site-directed mutagenesis technology.After transfected into PK15 cells for a certain period of time,RNA were extracted and was used to verify whether the eight ORFs were deleted or not and used for gene microarry analysis.The GO functions and KEGG pathway enrichment of differentially expressed genes were analyzed.[Results]P1 ORF1 is mainly involved in the biological processes of defense response to virus,signal transduction,regulation of Rab GTPase activity,and lipid metabolic process,and involved in the molecular functions of protein phosphatase inhibitor activity,phosphatidylinositol phospholipase C activity,2 iron,2 sulfur cluster binding,phosphoric diester hydrolase activity,and Rab GTPase activator activity,and in the KEGG pathways of secretion of digestive gland and nervous system development.P1 ORF2 is mainly involved in the biological processes of positive regulation of leukocyte chemotaxis,positive regulation of cell proliferation,positive regulation of cell migration,defense response to virus,regulation of cell growth,and involved in the molecular functions of insulin-like growth factor binding,and chemokine activity,and in the KEGG pathways of cytosolic DNA-sensing pathway,RIG-I-like receptor signaling pathway,toll-like receptor signaling pathway,chemokine signaling pathway,and cytokines,cytokine-cytokine receptor interaction.The biological processes,molecular functions and related pathways involving P1 ORF3 and ORF5 are basically similar to those of ORF2.P1 ORF8 is mainly involved in the biological processes of purine ribonucleotide biosynthetic process,amino acid transport,defense response to virus,amino acid transmembrane transport,and involved in molecular functions of N6-(1,2-dicarboxyethyl)AMP AMP-lyase(fumarate-forming)activity,iron-sulfur cluster binding,amino acid transmembrane transporter activity.[Conclusions]The analysis of the ORF functions of P1 virus lays a foundation for the study of its pathogenicity and pathogenesis.

Effects of endotoxin on expression of ras, p53 and bcl-2 oncoprotein in hepatocarcinogenesis induced by thioacetamide in rats

AIM To evaluate the relationship between expression of ras, p53, bcl 2 gene products, and hepatocarcinogenesis since endotoxemia produced from lipopolysaccharide admi nistration and/or the hypophagocytic state of splenectomy significantly accelerated hepatocarcinogenesis induced by thioacetamide. 〖WTH4〗METHODS〓〖WTXFZ〗The hepatocarcinoma model was induced by oral intake of 0 03% thioacetamide for six months. During the induction of hepatocarcinoma model, rats were additionally treated with splenectomy and/or lipopolysaccharide administration. The techniques of flow cytometry, immunohistochemistry and immunoelectronmicroscopy were applied to quantitative analysis of the expression of oncogene proteins. RESULTS In this model system, overexpression of ras p21 protein mainly occurred on precancerous cell population or in early stage of hepatocyte transformation. And the levels of ras p21 declined when nuclear DNA aneuploid increased. Expression of bcl 2 protein slowly and steadily rose with more hepatocytes staying in S+G2M phases as the hepatocarcinoma became more malignant. P53 was moderately expressed during the hepatocarcinogenesis. There was no statistical correlation between endotoxemia levels and the changes of ras, p53 and bcl 2 gene products. CONCLUSION Over expression of oncogene ras p21 was likely to be a precursor of the premalignant hepatocytes and it might be responsible for the initiation of hepatocarcinogenesis. Bcl 2 protein expression is proportional to the severity of the malignancies. P53 may be a key pathway on the transformation and development of hepatocarcinoma. This study confirmed the hypothesis that there are multiple genes and multiple steps involved in hepatocarcinogenesis. Expressions of oncogene proteins reflected the properties of the premalignant and malignant cells, but not directly related to endotoxemia statistically.[JP]

Inhibitory effects of polysaccharides isolated from Phellinus gilvus on benzo(a)pyrene-induced forestomach carcinogenesis in mice

AIM: Although polysaccharides from Phellinus mushrooms are a well-known material with anti-tumor properties, there is no information about the effect of polysaccharides from Phellinus gilvus (PG) on tumor. The modulating effect of polysaccharides isolated from PG on the benzo(a)pyrene (BaP)-induced forestomach carcinogenesis in ICR female mice was investigated in this study.METHODS: A forestomach carcinogenesis model was established in 40 ICR female mice receiving oral administration of BaP for 4 wk. The mice were randomly assigned to 4 groups (10 each). The mice in each group were treated with sterile water or PG for 4 and 8 wk (SW4,PGW4, SW8, and PGW8 groups). Eight or 12 wk after the first dose of BaP, forestomachs were removed for histopathological and RT-PCR analysis.RESULTS: In histopathological changes and RT-PCR analysis, sterile water-treated mice showed significant hyperplasia of the gastric mucosa with a significantly increased expression of mutant p53 mRNA compared to mice treated with PG for 8 wk.CONCLUSION: Polysaccharides isolated from PG may inhibit BaP-induced forestomach carcinogenesis in mice bydown-regulating mutant p53 expression.

Detecting the polymorphism sites of p53 and Fas genes of Han population in Zhejiang province

BACKGROUND： It is of significance for single nucleotide polymorphisms （SNPs）, a difference of rank, which exists widely in biology, genetics and other fields. OBJECTIVE： To detect polymorphism sites in exon-4 of p53 gene, promotor of Fas gene and intron-7 of Fas gene of healthy people in Han nationality in Zhejiang province. DESIGN： Simple random sampling. SETTING： Department of Surgery of the 118 Hospital of Chinese PLA.PARTICIPANTS： A total of 80 healthy people in Han nationality were selected from hospitals in Zhejiang province from August 2005 to January 2006. There were 43 males and 37 females aged from 3 to 78 years with the mean age of 39.5 years, and all subjects were consent. DNA which was used in genetic analysis was selected from peripheral venous blood of all subjects and maintained at -20℃.METHODS： Polymorphism sites in exon-4 of p53 gene, promotor of Fas gene and intron-7 of Fas gene were detected with directly DNA sequencing technique. MAIN OUTCOME MEASURES ： Polymorphism sites in exon-4 of p53 gene, promotor of Fas gene and intron-7 of Fas gene of healthy people in Han nationality in Zhejiang province. RESULTS： A total of 80 samples were involved in the final analysis. SNPs sites were found at the 119^th base of exon-4 of p53 gene （the 72^nd codon of p53 gene）, the 670^th base of upper start codon in promotor of Fas gene （Fas-670）, and the 995^th base of intron-7 of Fas gene, especially SNPs in the 995^th base of intron-7 pf Fas gene, i.e. C→A transversion, was a new site.CONCLUSION ： One unknown SNPs site is discovered in intron-7 of Fas gene of people in Han nationality in Zhejiang province. This study also proves that the 72^nd codon exists in p53 gene and the -670 polymorphism site exists in promotor of Fas gene.

DNA methylation and carcinogenesis in digestive neoplasms

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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 damageregulated 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.

PROMOTION OF CHEMICAL CARCINOGENESIS AND P53 EXPRESSION BY REDUCTION OF SUPEROXIDE DISMUTASE ACTIVITY IN THE LUNG OF RAT IN VIVO

In the present experiment,an inhibitor of superoxide dismutase(SOD),diethyldithiocarbamate(DETC),was used to decrease SOD activity for the observation of the relation between SOD activity and carcinogenesis and the expression of P53 protein in vivo.144 Wistar rats were used for the Present study.The results showed that the SOD activity reduction by DETC resulted markedly in the promotion of the carcinogenesis and the expression of P53 protein in the lung tissues,but the increase of SOD activity by the addition of plus SOD inhibited the pathological changes significantly.The frequency of the pathological lesions and Positive P53 expression are 36/42 and 8/42 in the animals without DETC and SOD:16/52 and 4/52 in the animals with SOD and 46/50 and 26/50 in the animals with DETC respectively.The results reported in this Paper suggest that:(1) the decrease of SOD activity enhanced the carcinogenesis induced by chemical carcinogen;(2) P53 gene may be associated with the process of tumorigenesis;and(3) at the same time the abnormal expression of P53 protein may be associated with the transition from premalignant lesions to carcinoma.

Expression of IGF-Ⅱ,p53,p21 and HBxAg in precancerous events of hepatocarcinogenesis induced by AFBI and/or HBV in tree shrews

INTRODUCTIONIn order to study the relationship between oncogeneexpression and HCC generation,we observed theprecancerous hepatic GGT loci,IGF-Ⅱ,p53 andp21 expression during hepatocarcinogenesis of treeshrew induced by hepatitis B virus (HBV) and/oraflatoxin B1 (AFB1).

Growth arrest-specific gene 2 suppresses hepatocarcinogenesis by intervention of cell cycle and p53-dependent apoptosis

BACKGROUND Growth arrest-specific gene 2(GAS2)plays a role in modulating in reversible growth arrest cell cycle,apoptosis,and cell survival.GAS2 protein is universally expressed in most normal tissues,particularly in the liver,but is depleted in some tumor tissues.However,the functional mechanisms of GAS2 in hepatocellular carcinoma(HCC)are not fully defined.AIM To investigate the function and mechanism of GAS2 in HCC.METHODS GAS2 expression in clinic liver and HCC specimens was analyzed by real-time PCR and western blotting.Cell proliferation was analyzed by counting,MTS,and colony formation assays.Cell cycle analysis was performed by flow cytometry.Cell apoptosis was investigated by Annexin V apoptosis assay and western blotting.RESULTS GAS2 protein expression was lower in HCC than in normal tissues.Overexpression of GAS2 inhibited the proliferation of HCC cells with wide-type p53,while knockdown of GAS2 promoted the proliferation of hepatocytes(P<0.05).Furthermore,GAS2 overexpression impeded the G1-to-S cell cycle transition and arrested more G1 cells,particularly the elevation of sub G1(P<0.01).Apoptosis induced by GAS2 was dependent on p53,which was increased by etoposide addition.The expression of p53 and apoptosis markers was further enhanced when GAS2 was upregulated,but became diminished upon downregulation of GAS2.In the clinic specimen,GAS2 was downregulated in more than 60%of HCCs.The average fold changes of GAS2 expression in tumor tissues were significantly lower than those in paired non-tumor tissues(P<0.05).CONCLUSION GAS2 plays a vital role in HCC cell proliferation and apoptosis,possibly by regulating the cell cycle and p53-dependent apoptosis pathway.

Transformation of Two VP1 Genes of O-and Asia 1-Type Foot-and-Mouth Disease Virus into Maize

The expression of antigens in transgenic plants has increasingly been used as an alternative to the classical methodologies for the development of experimental vaccines.This paper reports here the development of a novel oral immunization system for foot-and-mouth disease （FMD） in transgenic maize with two serotypes of the structural protein VP1 of the foot-and-mouth disease virus （FMDV） viz.,O-and Asia 1-type,respectively.The transgenic plantlets were identified and investigated by polymerase chain reaction （PCR）,Southern blot,and real-time PCR.Moreover,it was found that the VP1 genes in transgenic plants could be transmitted stably to the next generation through PCR detection.To our knowledge,this is the first report in an attempt to induce a protective systemic antibody response in animals by feeding the transgenic plants in which two serotypes antigen protein of FMDV expressed together.Results of the experiment provide the possibility of using plant-based vaccines as feedstuff or feedstuff additives.

Functionality of a bicistronic construction containing HEXA and HEXB genes encoding β-hexosaminidase A for cell-mediated therapy of GM2 gangliosidoses

Tay-Sachs disease and Sandhoff disease are severe hereditary neurodegenerative disorders caused by a deficiency ofβ-hexosaminidase A(HexA)enzyme,which results in the accumulation of GM2 gangliosides in the nervous system cells.In this work,we analyzed the efficacy and safety of cell-mediated gene therapy for Sandhoff disease and Sandhoff disease using a bicistronic lentiviral vector encoding cDNA of HexAα-andβ-subunit genes separated by the nucleotide sequence of a P2A peptide(HEXA-HEXB).The functionality of the bicistronic construct containing the HEXA-HEXB genetic cassette was analyzed in a culture of HEK293T cells and human umbilical cord blood mononuclear cells(hUCBMCs).Our results showed that the enzymatic activity of HexA in the conditioned medium harvested from genetically modified HEK293T-HEXA-HEXB and hUCBMCs-HEXA-HEXB was increased by 23 and 8 times,respectively,compared with the conditioned medium of native cells.Western blot analysis showed that hUCBMCs-HEXA-HEXB secreted both completely separated HEXA and HEXB proteins,and an uncleaved protein containing HEXA+HEXB linked by the P2A peptide.Intravenous injection of genetically modified hUCBMCs-HEXA-HEXB to laboratory Wistar rats was carried out,and the HexA enzymatic activity in the blood plasma of experimental animals,as well as the number of live cells of immune system organs(spleen,thymus,bone marrow,lymph nodes)were determined.A significant increase in the enzymatic activity of HexA in the blood plasma of laboratory rats on days 6 and 9(by 2.5 and 3 times,respectively)after the administration of hUCBMCsHEXA-HEXB was shown.At the same time,the number of live cells in the studied organs remained unchanged.Thus,the functionality of the bicistronic genetic construct encoding cDNA of the HEXA and HEXB genes separated by the nucleotide sequence of the P2A peptide was shown in vitro and in vivo.We hypothesize that due to the natural ability of hUCBMCs to overcome biological barriers,such a strategy can restore the activity of the missing enzyme in the central nervous system of patients with GM2 gangliosidoses.Based on the obtained data,it can be concluded that intravenous administration of hUCBMCs with HexA overexpression is a promising method of the therapy for GM2 gangliosidoses.The animal protocol was approved by the Animal Ethics Committee of the Kazan Federal University(No.23)on June 30,2020.

Insecticide induction of O-demethylase activity and expression of cytochrome P450 genes in the red imported fire ant (Solenopsis invicta Buren)

The red imported fire ant （Solenopsis invicta） is a global major invasive pest, and has caused significant economic, social and environmental impacts since its invasion to mainland of China in 2004. To date, chemical control has been the most effective measure. However, the long-term use of chemicals would lead to an unexpected rebound. To understand the risks and explore the mechanisms of detoxification or induction to insecticides in S. invicta, the O-demethylase activity and expression of cytochrome P450 genes of workers and queens, and the effects of chlorpyrifos and fipronil exposure in workers were investigated. Biochemical assays showed the O-demethylase activity of cytochrome P450 was significantly higher in workers than in queens （1.66-fold）, and was significantly induced in workers exposed to chlorpyrifos and fipronil, reaching a maximum （3.00- and 1.95-fold） at 48 h and then decreasing dramatically compared to controls （exposed to acetone counter- part）. The relative expression levels of 12 cytochrome P450 expressed sequence tags （ESTs） in workers were significantly higher than in queens （from 2.3- to 36.4-fold）. Multiple cytochrome P450 genes （except 9E4） were co-up-regulated （from 1.5- to 2.86-fold） in workers exposed to fipronil. These results indicated that the increased O-demethylase activity may result from the increased transcription levels of cytochrome P450 related to detoxification of insecticides in S. invicta. It appears that cytochrome P450 plays an important role in enhanced metabolic detoxification of insecticides. At the same time, it also provides the theoretical basis for resistance management and rational usage of insecticides to control S. invicta.

Quantitative detection of peripheral MDR genes in breast cancer before chemotherapy and their clinical significances

Objective： To explore expressions of multidrug resistance gene （MDR） product P170 and peripheral blood MDR1 mRNA in breast cancer tissue and their clinical significances. Methods： Fluorescent quantitative RT-PCR and immunohistochemistry were used to detect peripheral blood MDR1 mRNA before chemotherapy in breast cancer tissue samples from 32 cases with P170 positive （trial group） and 11 cases with P170 negative （control group）. Results： There were 14 cases （43.75%） peripheral blood MDR1 mRNA positive and 18 cases （56.25%） negative in 32 cases P170 positive breast cancer patients, while there were 6 cases （54.55%） peripheral blood MDR1 mRNA positive and 5 cases （45.45%） negative in 11 cases P170 negative breast cancer patients; there wasn＇t a significance difference with peripheral blood MDR1 mRNA express rate in P170 positive （43.75%） group and P170 negative （54.55%） group （x2 = 0.383, P 〉 0.05）. There were 12 cases （37.50%） Her-2 positive and 20 cases （62.50%） negative in P170 positive group; there were 2 cases （18.18%） Her-2 positive and 9 cases （81.82%） negative in P170 negative group; there wasn＇t a significance difference with Her-2 positive rate in P170 positive group （37.50%） and P170 negative （18.18%） group （χ^2= 1.391, P 〉 0.05）. There were 13 cases （40.63%） ER positive and 19 cases （59.37%） negative in P170 positive group; there were 7 cases （63.64%） ER positive and 4 cases （36.36%） negative in P170 negative group; there wasn＇t a significance difference with ER positive rate in P170 positive group （40.63%） and P170 negative （63.64） group （χ^2 = 1.742, P 〉 0.05）. There were 20 cases （62.50%） PR positive and 12 cases （37.50%） negative in P170 positive group; there were 4 cases （36.36%） PR positive and 7 cases （63.64%） negative in P170 negative group; there wasn＇t a significance difference with PR positive rate in P170 positive group （62.50%） and P170 negative （36.36%） group （χ^2 = 2.267, P 〉 0.05）. There were 9 cases （28.12%） with lymphaden metastasis and 23 cases （71.88%） without lymphaden metastasis in P170 positive group; there were 5 cases （45.45%） with lymphaden metastasis and 6 cases （54.55%） without lymphaden metastasis in P170 negative group; there wasn＇t a significance difference with lymphaden metastasis rate in P170 positive group （28.12%） and P170 negative （45.45%） group （χ^2 = 1.120, P 〉 0.05）. Conclusion： 1） There were possibly MDR expressing infrequently in carcinoma tissue and peripheral blood before chemotherapy. 2） FQ-RT-PCR for detecting of peripheral blood MDR1 mRNA is special, sensitive and reliable. It can be used as new molecular biology diagnostic maker dynamic detecting peripheral blood MDR1 mRNA for regulating chemotherapy proposal and elevating chemotherapy effect.

Changes of chlorogenic acid content and its synthesis-associated genes expression in Xuehua pear fruit during development

According to synthetic pathway of plant chlorogenic acid （CGA）, the expression patterns of genes encoding enzymes that are associated with CGA synthesis were studied in normally developed Xuehua pear fruit. The study demonstrated that CGA content in peel and flesh of Xuehua pear decreased as fruit development progressed, with a higher level in peel. The expression levels of PbPAL 1, PbPAL2, PbC3H, PbC4H, Pb4CL 1, Pb4CL2, Pb4CL6, PbHC T1 and PbHC T3 genes decreased in fruit, which was consistent with the pattern of variation in CGA content. That indicated that these genes might be key genes for influencing fruit CGA synthesis in Xuehua pear. However, Pb4CL7 gene expression profile is not consistent with variation of CGA content, hence, it may not be a key gene involved in CGA synthesis.

Characterization and expression analysis of genes encoding Taxol biosynthetic enzymes in Taxus spp.

Taxol(Paclitaxel),an important anticancer drug,is derived at very low yields from Taxus(yew)species that grow very slowly.In the present study,thirteen genes that encode enzymes involved in Taxol biosynthesis in Taxus spp.were analyzed with bioinformatics methods,and their expression levels in different tissues and after cold and hormone treatments were also analyzed.The results indicated that many cis-elements related to abiotic stresses and hormones were found in the promoter sequences of the 8 genes involved in Taxol biosynthesis.Moreover,the 13 enzymes encoded by the target genes were located in different organelles and had many phosphorylation sites in the response proteins.The 13 genes were expressed highly either in roots or in stems,with lower transcripts in needles,and they were highly expressed after treatment with cold,gibberellin,methyl jasmonate or coronatine,consistent with predictions based on the bioinformatics analysis.These results suggest that the factors such as hormones and abiotic stresses stimulate taxane biosynthesis in yews,providing an important way to sustainably generate taxanes from yew trees or their cell cultures to improve Taxol yields.

The design of aided software for osmotic stress responding genes mining in plant genome

A software and algorithm which based on random sequence model uses osmotic stress responding cis elements from existing information sources of biology was designed. It can infer the genic downstream function of Arabidopsis thaliana through analyzing its promoter region, and can offer effective aided analysis to mine osmotic stress responding genes in Arabidopsis thatiana genome. The practical application proves that this software can aid to analyze vast genic data and offer important data evidence.