Biomedical subjects

Jian Yu

Publications and source records attributed to Jian Yu.

At least 55 records · Page 3Linked to original sources

PubMed2004

Methylation profile of the promoter CpG islands of 14 "drug-resistance" genes in hepatocellular carcinoma.

AIM: To establish the DNA methylation patterns of the promoter CpG islands of 14 "drug-resistance" genes in hepatocellular carcinoma (HCC). METHODS: The methylation specific polymerase chain reaction in conjunction with sequencing verification was used to establish the methylation patterns of the 14 genes in the liver tissues of four healthy liver donors, as well as tumor and the paired non-cancerous tissues of 30 HCC patients. RESULTS: While 11 genes (ATP-binding cassette, sub-family G (WHITE), member 2(ABCG2), activating transcription factor (ATF2), beta-2-microglobulin (B2M), deoxycytidine kinase (DCK), occludin (OCLN), v-raf-1 murine leukemia viral oncogene homolog (RAF1), ralA binding protein 1 (RALBP1), splicing factor (45 kD) (SPF45), S-phase kinase-associated protein 2 (p45) (SKP2), tumor protein p53 (Li-Fraumeni syndrome) (TP53) and topoisomerase (DNA) II beta (TOP2B)) maintained the unmethylated patterns, three genes displayed to various extents the hypermethylation state in tumor tissues in comparison with the normal counterparts. The catalase (CAT) was hypermethylated in tumor and the neighboring non-cancerous tissue of one case (3.3%). Both glutathione S-transferase pi (GSTpi) (80%, 24/30 in tumor and 56.7%, 17/30 in the paired non-cancerous tissues) and cystic fibrosis transmembrane conductance regulator, ATP-binding cassette (sub-family C, member 7) (CFTR) (77%, 23/30 in tumor and 50%, 15/30 in the paired non-cancerous tissues) genes were prevalently hypermethylated in HCC as well as their neighboring non-cancerous tissues. No significant difference in the hypermethylation occurrence was observed between the HCC and its neighboring non-cancerous tissues. CONCLUSION: Hypermethylation of promoter CpG islands of both CFTR and GSTpi genes occurs prevalently in HCC, which may correlate with the low expression of these two genes at the mRNA level and has the profound etiological and clinical implications. It is likely to be specific to the early phase of HCC carcinogenesis.

Acyltransferases↗

PubMed2004

Methylation profile of the promoter CpG islands of 31 genes that may contribute to colorectal carcinogenesis.

AIM: To establish the methylation profile of the promoter CpG islands of 31 genes that might play etiological roles in colon carcinogenesis. METHODS: The methylation specific PCR in conjunction of sequencing verification was used to establish the methylation-profile of the promoter CpG islands of 31 genes in colorectal cancer (n = 65), the neighboring non-cancerous tissues (n = 5), colorectal adenoma (n = 8), and normal mucosa (n = 1). Immunohistochemically, expression of 10 genes was assessed on the home-made tissue microarrays of tissues from 58 patients. The correlation of tumor specific changes with each of clinical-pathologic features was scrutinized with relevant statistic tools. RESULTS: In comparison with the normal mucosa of the non-cancer patients, the following 14 genes displayed no tumor associated changes: breast cancer 1, early onset (BRCA1), cadherin 1, type 1, E-cadherin (epithelial) (CDH1), death-associated protein kinase 1 (DAPK1), DNA (cytosine-5-)-methyltransferase 1 (DNMT1), melanoma antigen, family A, 1 (directs expression of antigen MZ2-E) (MAGEA1), tumor suppressor candidate 3 (N33), cyclin-dependent kinase inhibitor 1A (p21, Cip1) (p21(WAF1)), cyclin-dependent kinase inhibitor 1B (p27, Kip1) (p27(KIP1)), phosphatase and tensin homolog (mutated in multiple advanced cancers 1) (PTEN), retinoic acid receptor, beta (RAR- , Ras association (RalGDS/AF-6) domain family 1 C (RASSF1C), secreted frizzled-related protein 1 (SFRP1), tissue inhibitor of metalloproteinase 3 (Sorsby fundus dystrophy, pseudoinflammatory) (TIMP3), and von Hippel-Lindau syndrome (VHL). The rest 17 targets exhibited to various extents the tumor associated changes. As changes in methylation of the following genes occurred marginally, their impact on the formation of colorectal cancer were trivial: adenomatous polyposis coli (APC) (8%, 5/65), Ras association (RalGDS/AF-6) domain family 1A (RASSF1A) (3%, 2/65) and cyclin-dependent kinase inhibitor 2A, alternated reading frame (p14(ARF)) (6%, 4/65). The following genes exhibited moderate changes in methylation: O-6-methylguanine-DNA methyltransferase (MGMT) (20%, 13/65), mutL homolog 1, colon cancer, nonpolyposis type 2 (E. coli) (hMLH1) (18%, 12/65), cyclin-dependent kinase inhibitor 2A (melanoma, p16, inhibits CDK4) (p16(INK4a)) (10%, 10/65), methylated in tumor 1 (MINT1) (15%, 10/65), methylated in tumor 31 (MINT31) (11%, 7/65). The rest changed greatly in the methylation pattern in colorectal cancer (CRC): cyclin A1 (cyclin a1) (100%, 65/65), caudal type homeobox transcription factor 1 (CDX1) (100%, 65/65), RAR- (85%, 55/65), myogenic factor 3 (MYOD1) (69%, 45/65), cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4) (p15(INK4b)) (68%, 44/65), prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (COX2) (72%, 47/65), cadherin 13, H-cadherin (heart) (CDH13) (65%, 42/65), CAAX box 1 (CXX1) (58%, 38/65), tumor protein p73 (p73) (63%, 41/65) and Wilms tumor 1 (WT1) (58%, 38/65). However, no significant correlation of changes in methylation with any given clinical-pathological features was detected. Furthermore, the frequent changes in methylation appeared to be an early phase event of colon carcinogenesis. The in situ expression of 10 genes was assessed by the immunohistochemical approach at the protein level: CDH1, CDH13, COX2, cyclin A1, hMLH1, MGMT, p14(ARF), p73, RAR- , and TIMP3 genes in the context of the methylation status in colorectal cancer. No clear correlation between the hypermethylation of the promoter CpG islands and the negative expression of the genes was established. CONCLUSION: The methylation profile of 31 genes was established in patients with colon cancer and colorectal adenomas, which provides new insights into the DNA methylation mediated mechanisms underlying the carcinogenesis of colorectal cancer and may be of prognostic values for colorectal cancer.

ADP-Ribosylation Factor 6↗

PubMed2004

SMAC/Diablo-dependent apoptosis induced by nonsteroidal antiinflammatory drugs (NSAIDs) in colon cancer cells.

Nonsteroidal antiinflammatory drugs (NSAIDs) form a paradigm for the chemoprevention of cancer, preventing colonic tumor progression in both experimental animals and humans. However, the mechanisms underlying the antineoplastic effects of NSAIDs are currently unclear. We found that the mitochondrial second mitochondrial-derived activator of caspase (SMAC)/direct inhibitor of apoptosis protein-binding protein with low pI (Diablo) protein translocates into the cytosol during NSAID-induced apoptosis in colon cancer cells. When SMAC/Diablo is disrupted by homologous recombination and RNA interference in these cells, the NSAID-induced apoptosis is abrogated. Biochemical markers of apoptosis, such as caspase activation, cytosolic release of cytochrome c and apoptosis-inducing factor, and mitochondrial membrane potential change, are accordingly decreased. These results establish that SMAC/Diablo is essential for the apoptosis induced by NSAIDs in colon cancer cells.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2004

Large-scale cDNA transfection screening for genes related to cancer development and progression.

A large-scale assay was performed by transfecting 29,910 individual cDNA clones derived from human placenta, fetus, and normal liver tissues into human hepatoma cells and 22,926 cDNA clones into mouse NIH 3T3 cells. Based on the results of colony formation in hepatoma cells and foci formation in NIH 3T3 cells, 3,806 cDNA species (8,237 clones) were found to possess the ability of either stimulating or inhibiting cell growth. Among them, 2,836 (6,958 clones) were known genes, 372 (384 clones) were previously unrecognized genes, and 598 (895 clones) were unigenes of uncharacterized structure and function. A comprehensive analysis of the genes and the potential mechanisms for their involvement in the regulation of cell growth is provided. The genes were classified into four categories: I, genes related to the basic cellular mechanism for growth and survival; II, genes related to the cellular microenvironment; III, genes related to host-cell systemic regulation; and IV, genes of miscellaneous function. The extensive growth-regulatory activity of genes with such highly diversified functions suggests that cancer may be related to multiple levels of cellular and systemic controls. The present assay provides a direct genomewide functional screening method. It offers a better understanding of the basic machinery of oncogenesis, including previously undescribed systemic regulatory mechanisms, and also provides a tool for gene discovery with potential clinical applications.

Animals↗

PubMed2004

Methylation profiles of thirty four promoter-CpG islands and concordant methylation behaviours of sixteen genes that may contribute to carcinogenesis of astrocytoma.

BACKGROUND: Astrocytoma is a common aggressive intracranial tumor and presents a formidable challenge in the clinic. Association of altered DNA methylation patterns of the promoter CpG islands with the expression profile of cancer-related genes, has been found in many human tumors. Therefore, DNA methylation status as such may serve as an epigenetic biomarker for both diagnosis and prognosis of human tumors, including astrocytoma. METHODS: We used the methylation specific PCR in conjunction with sequencing verification to establish the methylation profile of the promoter CpG island of thirty four genes in astrocytoma tissues from fifty three patients (The WHO grading: I: 14, II: 15, III: 12 and IV: 12 cases, respectively). In addition, compatible tissues (normal tissues distant from lesion) from three non-astrocytoma patients were included as the control. RESULTS: Seventeen genes (ABL, APC, APAF1, BRCA1, CSPG2, DAPK1, hMLH1, LKB1, PTEN, p14ARF, p15INK4b, p27KIP1, p57KIP2, RASSF1C, RB1, SURVIVIN, and VHL) displayed a uniformly unmethylated pattern in all the astrocytoma and non-astrocytoma tissues examined. However, the MAGEA1 gene that was inactivated and hypermethylated in non-astrocytoma tissues, was partially demethylated in 24.5% of the astrocytoma tissues (co-existence of the hypermethylated and demethylated alleles). Of the astrocytoma associated hypermethylated genes, the methylation pattern of the CDH13, cyclin a1, DBCCR1, EPO, MYOD1, and p16INK4a genes changed in no more than 5.66% (3/53) of astrocytoma tissues compared to non-astrocytoma controls, while the RASSF1A, p73, AR, MGMT, CDH1, OCT6, MT1A, WT1, and IRF7 genes were more frequently hypermethylated in 69.8%, 47.2%, 41.5%, 35.8%, 32%, 30.2%, 30.2%, 30.2% and 26.4% of astrocytoma tissues, respectively. Demethylation mediated inducible expression of the CDH13, MAGEA1, MGMT, p73 and RASSF1A genes was established in an astrocytoma cell line (U251), demonstrating that expression of these genes is likely regulated by DNA methylation. AR gene hypermethylation was found exclusively in female patients (22/27, 81%, 0/26, 0%, P < 0.001), while the IRF7 gene hypermethylation preferentially occurred in the male counterparts (11/26, 42.3% to 3/27, 11%, P < 0.05). Applying the mathematic method "the Discovery of Association Rules", we have identified groups consisting of up to three genes that more likely display the altered methylation patterns in concert in astrocytoma. CONCLUSIONS: Of the thirty four genes examined, sixteen genes exhibited astrocytoma associated changes in the methylation profile. In addition to the possible pathological significance, the established concordant methylation profiles of the subsets consisting of two to three target genes may provide useful clues to the development of the useful prognostic as well as diagnostic assays for astrocytoma.

Adolescent↗

PubMed2004

alpha-defensins released into stimulated CD8+ T-cell supernatants are likely derived from residual granulocytes within the irradiated allogeneic peripheral blood mononuclear cells used as feeders.

We recently demonstrated the ability of human beta-defensins to inhibit HIV-1 replication in vitro and demonstrated that alpha-defensins account for the great majority of beta-chemokine independent antiretroviral activity in stimulated CD8+ T-cell culture supernatants. In a follow-up study aimed at defining specific subpopulations of CD8+ T-cells that produce alpha-defensins, we have found that in the absence of irradiated allogeneic peripheral blood mononuclear cells (PBMC), stimulated CD8+ T-cell supernatants do not contain alpha-defensins. In our present work, we define residual granulocytes within PBMC fractions as the likely source. In addition, we describe in vitro conditions that promote the internalization of alpha-defensins by cells not natively producing these proteins, thus confounding our ability to define true alpha-defensin producer cells. In light of these findings, alpha-defensins released into stimulated CD8+ T-cell supernatants are unlikely to be derived from the CD8+ T-cells themselves. Moreover, our data imply that under some experimental conditions, a soluble noncytolytic anti-HIV-1 factor other than beta-chemokines is either not produced by CD8+ T-cells or is present in too small quantity to be effective.

Base Sequence↗

PubMed2004

Soluble eggshell membrane protein: preparation, characterization and biocompatibility.

The preparation, characterization and biocompatibility of soluble eggshell membrane (SEP) are reported. The dissolution process, which is the key step of the preparation of SEP, has been followed by scanning electron microscopy (SEM) to observe the changes of the surfaces and thickness of the eggshell membrane (ESM). The composition of SEP has been investigated by amino acid analysis and elemental analysis. Based on the fact that SEP losses significantly cystine, and that SEP has a higher content of sulfur, an assumption involving combination with 3-mercaptopropionic acid (the reagent used for reductive cleavage of disulfide bonds) following the cleavage of the original disulfide bonds has been proposed, which explains the solubility of SEP. The thermal and surface properties have been studied by thermogravimetric analysis (TGA) and contact angle measurement. The biocompatibility of SEP, as demonstrated by cell culture of NIH3T3, is comparable to collagen type I and superior to raw ESM either inside or outside surface.

Animals↗

PubMed2004

A novel protein-DNA interaction involved with the CpG dinucleotide at -30 upstream is linked to the DNA methylation mediated transcription silencing of the MAGE-A1 gene.

To understand the DNA-methylation mediated gene silencing mechanisms, we analyzed in cell culture of the promoter function of the MAGE-A1 gene, which is frequently demethylated and over-expressed in human hepatocellular carcinoma. We have established the correlation of the DNA methylation of the promoter CpG island with expression status of this gene in a panel of the established liver cancer cell lines. The crucial CpG dinucleotide(s) within the minimal promoter subjected to the control mediated by DNA methylation with profound biological functions was also delineated. Furthermore, a novel sequence-specific DNA-protein interaction at the -30 CpG dinucleotide upstream of the gene was found having a vital part to play in the DNA methylation mediated transcription silencing of the MAGE-A1 gene. Our results would not only provide new insights into the DNA methylation mediated mechanisms over transcription of the MAGE-A1 gene, but also pave the way for further defining the cross-talk among DNA methylation, histone modification and chromatin remodeling in detail.

Antigens, Neoplasm↗

PubMed2004

Apoptosis in human cancer cells.

PURPOSE OF REVIEW: Apoptosis, or programmed cell death, is a vital physiologic process to eliminate damaged or unwanted cells. Defects in apoptosis promote tumor formation and make cancer cells resistant to therapy. This review provides an overview of recent advances in the understanding of apoptosis in human cancer cells. RECENT FINDINGS: Recent studies revealed that the apoptotic machinery in humans consists of a molecular network of a large number of proteins. These proteins regulate a cascade of events in signaling, commitment and execution stages of apoptosis through multiple parallel pathways. Delineation of the basic mechanisms of apoptosis has shed light on how apoptosis is deregulated in human cancer cells. Therapeutic strategies based on apoptosis have also been designed to selectively target tumor cells. SUMMARY: Understanding the basic mechanisms of apoptosis and determining how cancer cells evade apoptosis will afford discoveries of new molecular targets and better cancer therapies.

Apoptosis↗

PubMed2004

Analysis of the weighting exponent in the FCM.

The fuzzy c-means (FCM) algorithm is one of the most frequently used clustering algorithms. The weighting exponent m is a parameter that greatly influences the performance of the FCM. But there has been no theoretical basis for selecting the proper weighting exponent in the literature. In this paper, we develop a new theoretical approach to selecting the weighting exponent in the FCM. Based on this approach, we reveal the relation between the stability of the fixed points of the FCM and the data set itself. This relation provides the theoretical basis for selecting the weighting exponent in the FCM. The numerical experiments verify the effectiveness of our theoretical conclusion.

Journal Article↗

PubMed2004

Real-time PCR assay using molecular beacon for quantitation of hepatitis B virus DNA.

Levels of hepatitis B virus (HBV) DNA in the blood serve as an important marker in monitoring the disease progression and treatment efficacy of chronic HBV infection. Several commercial assays are available for accurate measurement of HBV genomic DNA, but many of them are hampered by relatively low sensitivity and limited dynamic range. The aim of this study was to develop a sensitive and accurate assay for measuring HBV genomic DNA using real-time PCR with a molecular beacon (HBV beacon assay). The performance of this assay was validated by testing serial dilutions of the two EUROHEP HBV DNA standards (ad and ay subtypes) of known concentrations. The assay showed low intra-assay (<7%) and interassay (<5%) variations for both subtypes. Its dynamic range was found to be 10(1) to 10(7) copies per reaction (1.0 x 10(2) to 1.0 x 10(9) copies ml(-1)). The assay was further evaluated clinically using serum samples from 175 individuals with chronic hepatitis B. The HBV DNA level measured by this assay showed good correlation with that measured by the commercially available COBAS AMPLICOR HBV Monitor test (r = 0.901; P < 0.001). The higher sensitivity and broader dynamic range of this assay compared to the existing commercial assays will provide an ideal tool for monitoring disease progression and treatment efficacy in HBV-infected patients, in particular for those with low levels of HBV viremia.

Bacteriophage M13↗

PubMed2004

Molecular characterization of human immunodeficiency virus type 1 and hepatitis C virus in paid blood donors and injection drug users in china.

China is facing a rapid upsurge in cases of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infection due to large numbers of paid blood donors (PBD), injection drug users (IDU), and sexual partners of infected individuals. In this report, a total of 236 HIV-1-positive blood samples were collected from PBD, IDU, and their sexual partners in the most severely affected provinces, such as Henan, Yunnan, Guangxi, and Xinjiang. PCR was used to amplify the p17 region of gag and the C2-V3 region of env of HIV-1 and the 5' noncoding region and a region of E1/E2 of HCV. Genetic characterization of viral sequences indicated that there are two major epidemics of HIV-1 and multiple HCV epidemics in China. The PBD and transfusion recipients in Henan harbored HIV-1 subtype B', which is similar to the virus found in Thailand, and HCV genotypes 1b and 2a, whereas the IDU in Yunnan, Guangxi, and Xinjiang carried HIV-1 circulating recombinant forms 07 and 08, which resemble those in India, and HCV genotypes 1b, 3a, and 3b. Our findings show that the epidemics of HIV-1 and HCV infection in China are the consequences of multiple introductions. The distinct distribution patterns of both the HIV-1 and HCV genotypes in the different high-risk groups are tightly linked to the mode of transmission rather than geographic proximity. These findings provide information relevant to antiviral therapy and vaccine development in China and should assist public health workers in implementing measures to reduce the further dissemination of these viruses in the world's most populous nation.

Blood Donors↗

PubMed2004

[Localization of human telomere repeat binding factor 1 in telomerase-positive and-negative cells and its expression during cell cycle].

OBJECTIVE: To observe the distribution pattern of human telomere repeat binding factor 1(TRF1) in the telomerase-positive (HeLa) and telomerase-negative cells (WI38-2RA) and to investigate its expression level during the cell cycle. METHODS: The full-length sequences of TRF1(TRF1FL) and its mutant with N and C terminus deletion (TRF1DeltaNC) were generated by PCR amplification, the resulting fragments were cloned into pEGFP-C2 mammalian expression vector. GFP-tagged proteins were verified by Western blotting with rabbit anti-TRF1 and mouse anti-GFP antibodies after cell transfection. Immunofluorescence staining were performed to detect the TRF1 localization in HeLa and WI38-2RA cells. Metaphase spreads from HeLa cells were also prepared to observe TRF1 localization in chromosomes. HeLa cells were arrested by thymidine and nocodazole at different cell stages. Cell cycles were analyzed by flow cytometry and TRF1 levels were evaluated by semi-quantitative Western blotting. RESULTS: TRF1FL and TRF1PNC fragments were sized about 1.3 kb and 0.95 kb. GFP-tagged TRF1FL and TRF1DeltaNC proteins were 80 kD and 60 kD, respectively. In both HeLa and WI38-2RA cells, TRF1FL had a speckled distribution in the nuclei,however, TRF1FL did not coincide with promyelocytic leukemia (PML) nuclear body in HeLa cells while it exclusively did in WI38-2RA cells. Moreover, TRF1FL was exactly localized at the termini of metaphase spreads in HeLa cells. In contrast, TRF1PNC was diffusely distributed throughout the nuclei. Analysis by semi-quantitative Western blotting indicated that TRF1 levels increased with cell cycle progression, which reached the zenith at the M phase and went down to the nadir at G1/S point. The TRF1 level at M phase was about 3.9 times than that at G1/S point(t=12.92iP<0.01). CONCLUSION: TRF1 has a different localization in telomerase-positive and telomerase-negative cells, which suggests TRF1 might exert different functions in these cells. TRF1 level is regulated with cell cycle.

Cell Cycle↗

PubMed2004

[Telomerase activity of human bone marrow mesenchymal stem cells].

OBJECTIVE: To investigate the telomerase activity in mesenchymal stem cells (hMSCs) from human bone marrow after their in vitro committed differentiation into adipocytes and cryopreservation. METHODS: hMSCs were isolated from human bone marrow. The isolated hMSCs were induced to differentiate into adipocytes in vitro or cryopreserved. TRAP assay (telomerase repeat amplification protocol assay) was employed to detect telomerase activity in those hMSCs. RESULTS: Telomerase activity (RTA) in hMSCs (n=19) was (1.46 +/-0.67)%, while that in hMSCs-derived adipocytes (n=3) was (11.80 +/-2.52)% (P<0.001). RTA of hMSCs-passage 1.3 (n=10) was (1.46+/-0.83)%, and that of hMSCs-passage 4-7(n=9) was (1.46 +/-0.47)% (P=0.99). Cryopreservation did not affect the telomerase activity in hMSCs, RTA of fresh hMSCs (n=13) was (1.41 +/-0.44)%, RTA of frozen hMSCs (n=6) was (1.57 +/-1.07)% (P=0.64). CONCLUSION: hMSCs are telomerase-negative, but telomerase activity in hMSCs-derived adipocytes is upregulated.

Adipocytes↗

PubMed2004

[Isolation of Tara protein and its gene cloning].

OBJECTIVE: To isolate and identify TRF1 immunoprecipitating protein complex and to clone the candidate gene. METHODS: The co-immunoprecipitation assay was employed to isolate TRF1 protein complex and the immunoprecipitate was subjected to MALDI-TOF mass spectrometry for protein identification. The candidate gene was amplified by temperature-gradient PCR from human testis cDNA library and then cloned into pEGFP-C2 vector for eukaryotic expression. The amplified gene was verified by direct sequencing and GFP-tagged protein was confirmed by immunoblotting. RESULTS: Tara protein with the size of 68 kD was identified from the TRF1 precipitate. The candidate gene amplified from cDNA library was about 1.7 kb as expected. Sequencing demonstrated the amplified fragment had 99.9% of homogenesis with Tara CDS sequence (gi:30474869). GFP-tagged fusion protein was about 100 kD. Tara was diffusely distributed in cytoplasm at interphase and in whole cells at mitotic phase. CONCLUSION: Tara might be an interacting protein with TRF1. However, further investigation would be required to confirm if they were bona fide partners.

Cloning, Molecular↗

PubMed2004

[Expression of human telomere repeat binding factor 1 (TRF1) in acute leukemia cells and its correlation with telomerase activities].

OBJECTIVE: To study the expression of human telomere repeat binding factor 1 (TRF1) to investigate the correlation of telomerase activity with acute leukemia. METHODS: Leukemic cells were collected from 30 cases of acute leukemia. Realtime quantitative PCR with fluorescence probe hybridization was used to measure expression of TRF1 and hTERT mRNA in leukemic cells. RESULTS: TRF1 mRNA expression was 0.0126 (0.0127-0.0546) in acute non-lymphocytic leukemia (ANLL), which was lower than that in normal mononuclear cells [0.0457 (0.00839-0.262), P<0.001], but its expression in acute lymphoblastic leukemia (ALL) cells [0.0745 (1.92 x 10(-6)-0.193)] had no significant difference compared with that in normal mononuclear cells. TRF1 expression in ANLL cells was significantly lower than that in ALL cells (P=0.001). The expressions of TRF1 mRNA in AL cells and normal mononuclear cells had no significant correlation with expression of hTERT mRNA (r=-0.173, P=0.207). CONCLUSION: The expression of TRF1 is lower in ANLL cells, which indicates TRF1 may have some effect on telomerase activity by regulating telomere length in ANLL cells.

Adolescent↗

PubMed2004

[Expression of Pin1 in malignant hematopoietic cells and its relation with cell cycle].

OBJECTIVE: To study the expression of peptidyl-prolyl cis/trans isomerase (PPIase or Pin1) in malignant hematopoietic cells and its relation with cell cycle. METHODS: Realtime quantitative PCR with fluorescence probe hybridization was used to measure expression of Pin1 mRNA in malignant hematopoietic cell lines and normal mononuclear cells separated from bone marrow. HeLa cells were blocked with Thymidine and Nocodazole in different cell phases and then the expression of Pin1 mRNA and protein were detected by realtime-PCR and immunoblotting. RESULTS: The expression of Pin1 in malignant hematopoietic cell lines was significantly higher than that in normal controls (0.339 +/-0.093 compared with 0.038 +/-0.005, P<0.01). Its expression in myeloid malignant hematopoietic cell lines was significantly higher than that in normal controls (0.388 +/-0.115 compared with 0.038 +/-0.005, P<0.01) and so was the malignant lymphocytic cell lines (0.226 +/-0.166 compared with 0.038 +/-0.005, P<0.01). The expression of Pin1 was closely correlated with cell cycle. It was the highest in G1 phase and the lowest in S phase (110.762 +/-16.737 compared with 4.080 +/-0.634, P<0.01). CONCLUSION: Pin1 is overexpressed in malignant hematopoietic cell lines and its expression is different during cell cycle that is highest in G1 phase and lowest in S phase.

Cell Cycle↗

PubMed2004

Correlation between methylation profile of promoter cpg islands of seven metastasis-associated genes and their expression states in six cell lines of liver origin.

BACKGROUND & OBJECTIVE: DNA methylation has been regarded as an important epigenetic signature reflecting the transcription state of DNA in cells. This study was to assess the correlation between methylation state of promoter CpG islands of metastasis-associated genes and their expression in 6 liver cell lines, including 5 cancerous. METHODS: Methylation specific polymerase chain reaction method (MSP) and DNA sequencing verification were used to analyze the methylation state of promoter CpG islands of 7 genes (ASPH, ENO3, ITGA9, LRP6, MTHFD2, OXCT, and SRP72) in 5 liver cancer cell lines (BEL-7402, SMMC-7721, Hep3B, HepG2, and HCCLM3), and 1 immortalized liver cell line (L-02). Expression of 6 genes in this list was assessed by the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. RESULTS: The methylation state of genes was either unmethylated or heterozygously methylated in these 7 liver cell lines. Except for no expression of OXCT gene was detected by RT-PCR in both HepG2 and HCCLM3 cells where it was heterozygously methylated, there was expression of genes in all the remaining cases. CONCLUSION: Although expression state of genes in this study supported the general notion that hypermethylation state of promoter CpG islands of genes represents the silenced state of gene transcription, there were exceptions. Therefore, other mechanisms are likely to contribute to the observed expression state of these 7 genes in this study.

Calcium-Binding Proteins↗