N Jiang

Changsha Medical University, Ch’ang-sha-shih, Hunan, China

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Publications (10)4.43 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Our goal was to better define the extent and specificity of deletion in the 7q32-qter chromosomal region in nasopharyngeal carcinoma (NPC). Polymerase chain reaction-based deletion analysis was performed on DNA samples from 24 paired NPCs and corresponding germlines using 13 microsatellite markers mapped to chromosome subbands 7q31.3-q36. Loss of heterozygosity of at least 1 marker in this interval was found in 18 (75%) of 24 tumor specimens. Particularly frequent allelic losses were identified at 5 loci: D7S495 (46%), D7S509 (42%), D7S500 (45%), D7S631 (30%), and D7S514 (35%). Two shortest regions of overlap could be identified in this interval, although the most common shortest region of overlap appeared to lie around D7S500 between but not including D7S631 and D7S495, on chromosome subband 7q32. These results suggest that at least 2 putative tumor suppressor genes important in the pathogenesis of NPC are present in the examined interval, an interval that has also been found to harbor deletions in breast and prostate carcinomas.
    Otolaryngology Head and Neck Surgery 04/2002; 126(3):296-300. · 1.73 Impact Factor
  • N Jiang, F Zhan, L Cao, K Yao, G Li
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    ABSTRACT: To investigate the effects of retinoic acid (RA) on the growth, morphology, oncogene expression and regulation of nasopharyngeal carcinoma cells. Nasopharyngeal carcinoma cell line (HNE1) was induced by RA. The RA-treated and control cells were established and cellular morphology and growth patterns were defined. Oncogene expression and regulation were detected by Northern hybridization and DNase-I hypersensitive site analysis. RA markedly inhibited cell growth. The growth of HNE1 cells was reduced to 50% of the control level on the 4th day of RA (10(-4) mol/L) treatment. After 4 days of treatment, the rapidly growing polygonal cells were reversed into a slow growing phenotype, with flattened morphology similar to fibroblast-like cells. Northern hybridization showed that c-myc and c-Ha-ras expression was high in HNE1 cells and undetectable in normal blood cells. c-myc was down-regulated at 48 h of RA treatment. In contrast, the c-Ha-ras was not affected. DNase I hypersensitive site analysis detected changes in the regulatory elements of c-myc and c-Ha-ras genes. 5 hypersensitive sites were found in the c-myc of HNE1 cells, while 3 hypersensitive sites disappeared upon HNE1 induction. However, only 1 hypersensitive site was found in c-Ha-ras of RA treated cells and controls. In normal peripheral white blood cells, no DNase I hypersensitive sites were found in the inactive c-myc and c-Ha-ras gene. RA can induce differentiation in a nasopharyngeal carcinoma cell line at high concentration of RA; HNE1 shows some similar patterns of DNase I hypersensitive sites with the common one in other types of cells expressing c-myc. The repression of c-myc expression with induction is accompanied by the loss of 3 DNase-I hypersensitive sites; c-myc has more than one inactive conformation.
    Chinese medical journal 10/2000; 113(9):823-6. · 0.90 Impact Factor
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    ABSTRACT: To obtain the novel genes associated with human nasopharyngeal carcinoma(NPC) on chromosome 3p24-26. Twenty epithelial-derived expressed sequence tags(EST) were selected from chromosome 3p24-26 where loss of heterozygosity(LOH) frequently occurs in NPC tissues. Primers were designed based on the sequences of these ESTs. RT-PCR was used to amply their corresponding cDNA fragments from NPC cell line HNE1 and primary cultures of normal nasopharyngeal epithelial cells. The differential expression of two ESTs, T93093 and R41598, was confirmed by Northern blot. Then, expression of EST T93093 was further detected in 7 normal nasopharyngeal and 19 NPC biopsies. cDNA library screening was used to get its full cDNA sequence and the sequence of this novel gene was analyzed by bioinformatics. Thirteen ESTs(T62511, N39155, N68660, R61275, T95314, R06143, H52697, H66521, AA128685, AA284537, N52379, AA054180, and H98090) showed the similar expression level and 5 ESTs(R00732, R07573, R98052, H91759, H17566) showed no expression in both types of cells. EST T93093 was down-expressed, whereas EST R41598 up-expressed in NPC HNE1 cells. The EST T93093 was also found to be down-expressed in 26.3%(5/19) of NPC biopsies. The full length cDNA of this gene was obtained and named NAG-7, which is located at chromosome 3p25.3. Its 1677 bp full length cDNA has a potential open reading frame(ORF) predicting a 94 amino acid protein with a molecular weight of 11023.87 Dalton. Bioinformatics analysis of the NAG-7 gene shows that it is a transmembrane protein containing a protein kinase C(PKC) phosphorylation site and a myristyl site. It has no significant homology to any reported genes in database of GenBank(AF086709). NAG-7 is a novel gene down-expressed in NPC, which may be involved in the development of NPC.
    Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 09/2000; 17(4):225-8.
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    ABSTRACT: To isolate and clone the tumor suppressor gene on chromosomal region 7q32 correlated with the carcinogenesis of human nasopharyngeal carcinoma (NPC). The genotypes of polymorphic microsatellite markers on 7q32 in DNA from 24 biopsies of nasopharyngeal carcinoma and matched normal blood cells were identified. The expression levels of 20 expressed sequence tags (ESTs) on 7q32 between human nasopharyngeal carcinoma epithelial 1 (HNE1) and primary cultures of normal nasopharyngeal epithelial (PNNE) cells were compared using differential RT-PCR and Northern hybridization. The quantity of AA070437 DNA and mRNA was detected by differential PCR and differential RT-PCR, respectively. Loss of heterozygosity (LOH) was found in 25%-46% of NPC biopsies. AA070437 EST expression was down-regulated in HNE1 cell compared to PNNE cells. The down-regulation of AA070437 was found in 30.7% of NPC biopsies and allelic loss of AA070437 was observed in 29.1% of NPC biopsies. Our results show that AA070437 EST is negatively related with the occurrence of human NPC and may represent a candidate tumor suppressor gene of NPC on 7q32.
    Chinese medical journal 08/2000; 113(7):650-3. · 0.90 Impact Factor
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    ABSTRACT: The present research group had found high frequency of loss of heterozygosity(LOH) of D7S500-D7S495 on chromosome band 7q32 in nasopharyngeal carcinoma, this study was conducted to further find the deletion region. Higher density of loci on 7q32 in 30 tumors was studied by using microsatellite analysis. The frequency of LOH was 63.3%. The highest frequency of LOH was identified at the loci of D7S500-D7S509-D7S495, among which a common deletion of D7S509 was found. A putative tumor suppressor gene may be present around D7S509.
    Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 07/2000; 17(3):153-6.
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    ABSTRACT: To search differentially expressed sequences correlated with pathogenesis of human nasopharyngeal carcinoma (NPC), including the candidates of tumor suppressor genes. Representational difference analysis (RDA) was performed to isolate differentially expressed sequences between cDNA from normal human primary cultures of nasopharyngeal epithelial cells and cDNA from NPC cell line HNE1. The source of differentially expressed products were proved by Southern blot, Northern blot and in situ hybridization. The fragments were cloned with pGEM-T easy kit and sequenced by the chain termination reaction. Four differentially expressed cDNA fragments were isolated in the fourth subtractive hybridization using cDNA from normal human nasopharyngeal epithelial cells as tester amplicon and cDNA from NPC cell line HNE1 as driver amplicon by cDNA RDA. These differential cDNA fragments revealed that they really came from the tester amplicon and were not expressed or down-regulated in the NPC HNE1 cells. Some of the genes were expressed only in human nasopharyngeal epithelial cells but deleted or down-regulated in the biopsies of NPC. Of these obtained clones, some were the sequences of the human known genes including house-keeping genes, the others represented novel gene sequences. The differentially expressed products including the candidates of tumor-suppressor genes may be associated with the initiation of the NPC.
    Chinese medical journal 07/1999; 112(6):538-42. · 0.90 Impact Factor
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    ABSTRACT: To isolate and clone the tumor suppressor gene on chromosomal region 7q32 that corelated with the occurrence of human NPC, we detected the genotype of polymorphic microsatellite markers on 7q32 in 24 nasopharyngeal carcinoma biopsies and matched normal lymphocyte DNA. LOH was found in 30% biopsies. Using differential RT-PCR and Northern hybridization we compared the expression level of 20 EST on 7q32 between NPC cell line HNE1 and primary culture of normal nasopharyngeal epithelial cell, and found AA070437 EST expressed high in primary culture of normal nasopharyngeal epithelial cell, but very low in HNE1. Differential RT-PCR (dRT-PCR) analysis showed that the expression level of AA070437 was lower in 30.7% NPC biopses than in normal cell. Differential PCR (dPCR) showed that allelic loss of AA070437 was observed in 29.1% NPC biopses. This EST is a part of sequence of a new gene compared with GeneBank database. Our results showed that AA070437 EST negatively related with the occurrence of human NPC is a candidate of tumor suppressor gene of NPC on 7q32.
    Acta Genetica Sinica 02/1999; 26(4):301-8.
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    ABSTRACT: To search differentially expressed sequences correlated with pathogenesis of human nasopharyngeal carcinoma (NPC), including the candidates of tumor suppressor genes. cDNA representational difference analysis (RDA) was performed to isolate differentially expressed sequences between cDNA from normal human primary cultures of nasopharyngeal epithelial cells and cDNA from NPC cell line HNE1. The sources of differentially expressed products were proved by Southern blot and Northern blot. The fragments were cloned with pGEM-T easy kit and sequenced by the chain termination reaction. Four differentially expressed cDNA fragments were isolated in the fourth subtractive hybridization using cDNA from normal human primary cultures of nasopharyngeal epithelial cells as tester amplicon and cDNA from NPC cell line HNE1 as driver amplicon by cDNA RDA. These differential cDNA fragments revealed that they really came from the tester amplicon and were not expressed or down-regulated in the NPC HNE1 cells. Of these obtained clones, some are the fragments of the human known genes including house-keeping genes, the others are novel genes. NPC involves alteration of multiple genes. Some of known genes matched with the differentially expressed sequences have an effective suppressive ability on the carcinoma.
    Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 01/1999; 15(6):341-4.
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    ABSTRACT: To establish partial gene expression map of 7q32 in nasopharyngeal carcinoma (NPC) cell line, tissues and primary culture normal nasopharyngeal epithelial cells. We detected the expression of 20 ESTs at 7q32 in NPC cell line HNE1,13 NPC biopsies and primary culture normal nasopharyngeal epithelial cells using differential RT PCR and Northern hybridization. 8 ESTs (AA188181, AA13079,N27556, AA031919, N22721, H20825, T91284, AA001936) expressed equally in both of HNE1 and primary culture normal nasopharyngeal epithelial cells; 7 ESTs (T64215, AA025822, R60014,R80002,H06688, R60192,R95096) expressed in neither of them; 3 ESTs (H19830,W72688,AA130630) overexpressed in HNE1 ; and 2 ESTs (AA070437, H90882) overexpressed in primary culture normal nasopharyngeal epithelial cells. W72688 and H19830 each overexpressed in 77%(10/13) of NPC biopsies; AA070437 down-expressed in 30.7% of NPC biopsies. Partial gene expression map of 7q32 in nasopharyngeal carcinoma cell line ,tissues and primary culture normal nasopharyngeal epithelial cells has been established. The up-regulation of W72688, H19830 and down-regulation of AA070437 may be related to the occurrence of NPC.
    Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 11/1998; 15(5):267-70.
  • L Deng, N Jiang, G Tan
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    ABSTRACT: To determine the frequency and extent of loss of heterozygosity (LOH) on chromosome 3p in nasopharyngeal carcinoma (NPC). Sixteen loci on chromosome bands 3p21-26 in 24 tumors was studied by using microsatellite analysis. LOH on 3p21-26 was found in 16 of 24 tumors (66.7%). The highest frequency of the allelic loss was found in two adjacent loci D3S1620(50%, 11/22) and D3S1560 (50%, 9/18). Eight cases showed LOH in one contiguous region and 5 cases in more than one region. Sample 1, 3, 4, 7, 8, 10, 16, 17, 18, 19, and 22 had a contiguous stretch of allelic loss between D3S1297 and D3S1597. The smallest common LOH/deletion region seems likely to lie between D3S1620(3p26.2-26.3) and D3S1560(3p25.3). The allelic loss map defined here will facilitate finer mapping of putative tumor suppressor gene loci and positional cloning of such genes, which may play a role in carcinogenesis of NPC.
    Zhonghua zhong liu za zhi [Chinese journal of oncology] 08/1998; 20(4):248-50.