Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nucleoside diphosphate (NDP) kinase/Nm23 is highly expressed in certain malignant tissues, as compared with the rate found in normal or hyperplastic tissues. The potential role of this overexpression in tumor progression and the mechanisms involved in it remain to be determined. We studied the ultrastructural localisation of the NDP kinase, and in particular looked for an association of this enzyme with the microtubules or cytoplasmic membrane. Using immunocytochemical methods with an antiserum raised against NDP kinase A, we analysed tissue sections of breast carcinomas and cells in culture derived from a cervical cancer. In malignant cells, a strong labeling of the cytoplasm, related to ribosomes, was observed. No labeling of microtubules, or other intracytoplasmic components was found. No labeling of the nucleus was noted. In contrast, a strong labeling of the cytoplasmic membrane of most malignant cells was observed. In the cytoplasm of non-malignant stromal cells, a slight labeling of ribosomes was observed. These results must be taken into account with regard to the different existing hypotheses relative to the role of the NDP kinase in tumor progression, and in particular relative to its activation function on the GTP-binding proteins involved in membrane signal transduction.
 ...
PMID:[Ultrastructural immunocytochemical localization of diphosphate kinase/Nm23 in human cancer cells]. 133 98

The product of the nm23-H1 gene, reported to be a metastatic suppressor gene, was recently identified as the nucleoside diphosphate (NDP) kinase A, and was found to be overexpressed in several types of malignant tumors as compared with normal tissues. In order to determine whether NDP-kinase expression serves as a marker for metastatic potential and whether hyperproliferation of neoplastic cells would correlate with expression, we analyzed NDP-kinase levels and activity by immunohistochemical staining and by an enzymatic assay in 13 benign and 98 malignant breast-tissue specimens. Our results confirm that NDP-kinase expression increases in malignant cells of breast carcinomas, but cannot be considered as a biological marker of metastatic dissemination. No correlation was found between NDP-kinase activity and S phase, taken as an index of cell proliferation. Moreover, no correlation was observed between NDP-kinase activity and tumor size, histoprognostic index, estrogen receptors or progesterone receptors. The mechanism of over-expression of NDP in malignant cells and its role in tumor progression remain to be determined.
 ...
PMID:Nucleoside diphosphate kinase/NM23 expression in breast cancer: lack of correlation with lymph-node metastasis. 153 18

Tumor progression to the metastatic phenotype is accompanied in certain cell types by reduced expression of the nm23 gene. We have localized human nm23-H1 to chromosome 17 by somatic cell hybrid analysis. Regional localization in the CEPH database and in situ hybridization is reported. Somatic allelic deletion of nm23-H1 was observed in human breast, renal, colorectal, and lung carcinoma DNA samples, as compared to DNA from matched normal tissues. A homozygous deletion of nm23-H1 was observed in a lymph node metastasis of a colorectal carcinoma, indicating that nm23-H1 can be recessively inactivated. The data identify nm23-H1 as a novel, independent locus for allelic deletion in human cancer, a characteristic shared with previously described suppressor genes.
 ...
PMID:Somatic allelic deletion of nm23 in human cancer. 201 8

The transcription of human nm23 genes (nm23-H1, nm23-H2) is involved in suppression of tumor metastasis or tumor progression. Therefore the characterization of transcriptional regulatory mechanisms for both nm23 genes is very important. In this study we have isolated and analyzed the 5'-flanking region of the human nm23-H2 gene and estimated the distance to 4 kb between nm23-H2 and nm23-H1 genes. We localized the known microsatellite D17S396 within this region. Furthermore the identification of possible binding sites for MYC proteins and additionally the NM23-H2 protein itself (the transcription factor PuF for c-myc gene activation) is of importance with respect to possible para- and autoregulatory interactions. A comparison of the promoter sequences of both human nm23 genes revealed no significant sequence homology.
 ...
PMID:Characterization of the human nm23-H2 promoter region and localization of the microsatellite D17S396. 748 60

Levels of nm23-H1/nucleoside diphosphate kinase (NDP kinase) expression have been reported to correlate inversely with metastatic potential in some tumors but not in others. Whether or not nm23 gene product is associated with metastatic potential in lung cancer is not clear as yet. We therefore immunohistochemically examined the expression of nm23 gene products in primary lung adenocarcinomas according to cytologic subtypes in order to clarify the association of its expression with the clinical features of the disease. Seventy-two (64.9%) of the 111 lung adenocarcinomas were positive for nm23 protein. In lung adenocarcinoma of Clara cell type, high levels of nm23 expression were associated with advanced pathologic stage, positive lymph node status, and poorer prognosis (P < 0.05). However, no correlation with clinical outcome was observed in other cell types. Our data suggest that higher levels of nm23 expression are associated with tumor progression in lung adenocarcinoma of Clara cell type.
 ...
PMID:Immunohistochemical analysis of nm23/NDP kinase expression in human lung adenocarcinoma: association with tumor progression in Clara cell type. 792 30

Allelic deletions in the nm23, a metastasis suppressor gene, are known to occur in neuroblastomas, breast and colorectal carcinomas. Down-regulation of nm23 expression has been reported in various rodent and human tumor cells with high metastasis phenotype. Colorectal tumors showed overexpression of nm23. To elucidate the regulatory mechanisms of nm23, we isolated, cloned and sequenced the presumptive regulatory DNA fragment spanning the 5' region of the human nm23-H1 gene. The region's nucleotide sequence shows the presence of motifs typical for transcriptional elements such as TFIID, AP-1 and CTF/NF1. A common transcription initiation site is located at -136 upstream from the first ATG codon in placenta tissue, in breast, colorectal, prostate tumor cell lines and in primary colorectal tumor. Multiple transcription start sites were identified in tumor cell lines and colorectal tumor. When the promoter element was linked to a reporter gene, chloramphenicol acetyltransferase (CAT) and transfected in human 2fTGH cells, strong CAT activity was detected, which also showed that the presence of AP-1 and CTF/NF1 elements are essential for promoter activity. A detailed study of the structure and function of the promoter element of the nm23-H1 gene will help in understanding the regulatory mechanisms of nm23 expression and its role in tumor progression, especially in metastasis.
 ...
PMID:Isolation and characterization of the promoter region of human nm23-H1, a metastasis suppressor gene. 808 95

Expression of the candidate metastasis-suppressor gene nm23-H1 has been shown to correlate inversely with metastatic potential in some human tumors, but not in all. Until now, few studies have been carried out on the activity of the homologous nm23-H2 gene in human cancer. No nm23 transcription studies exist for human lung cancer so far. To determine whether the nm23 genes could have a metastasis-suppressor function in non-small-cell lung carcinoma (NSCLC), pulmonary sarcoma and carcinoids, we analysed both nm23-HI and nm23-H2 mRNA levels in 37 tumor samples obtained from patients who underwent potentially curative resection between 1986 and 1990, and in 4 metastatic tumors obtained from autopsy. As compared to corresponding healthy lung parenchyma, both nm23-HI and nm23-H2 transcript levels were elevated in 37 of 41 tumors. The increases in nm23 mRNA expression were stronger in advanced stages of squamous-cell carcinoma, large-cell carcinoma, sarcoma and carcinoids than in early stages of the respective tumor types. Within stages I and II of squamous-cell carcinoma, significantly higher nm23 mRNA levels were found in poorly differentiated tumors than in moderately differentiated ones. Moreover, an inverse correlation between nm23 expression and disease-free survival of the patients was observed. In conclusion, our results indicate that the increased nm23 expression in the analysed tumors is not consistent with the proposed metastasis-suppressor function, but the 2 nm23 genes nevertheless may be implicated in the mechanism of tumor progression.
 ...
PMID:High levels of nm23-H1 and nm23-H2 messenger RNA in human squamous-cell lung carcinoma are associated with poor differentiation and advanced tumor stages. 837 20

Carcinogenesis requires a complex series of genetic changes often involving multiple oncogenes and the inactivation of multiple tumor-suppressor genes. We presently examined the effect of the Krev-1 tumor-suppressor gene on the tumorigenic and metastatic potential of Ha-ras-transformed cloned rat embryo fibroblast (CREF) cells. Ha-ras-transformed CREF cells are morphologically transformed and anchorage independent; produce reduced levels of nm23-H1 (a putative metastasis-suppressor gene product) and TIMP-1 (tissue inhibitor of metalloproteinase 1) transcripts and mRNA compared with CREF cells; produce increased levels of cripto, 94-kDa gelatinase/type IV collagenase (94-kDa GEL), osteopontin (OPN) and transin/stromelysin transcripts and mRNA compared with CREF cells; and are tumorigenic and metastatic in both nude mice and syngeneic rats. Ha-ras-transformed CREF cells coexpressing the Krev-1 gene display a reversion in cellular phenotype and gene expression to that of untransformed CREF cells. However, Ha-ras/Krev-1-coexpressing CREF cells retain, albeit with extended latency periods, both tumorigenic and metastatic potential that is not related directly to the final level of Ha-ras or Krev-1 mRNA or the Ha-ras p21 transforming protein. Development of metastatic potential is, however, directly correlated with a reduction in nm23-H1 and TIMP-1 transcription and mRNA levels and an enhanced expression of cripto, 94-kDa GEL, osteopontin and transin. In contrast, expression of additional tumor-suppressor genes, such as the RB gene and p53, or genes associated with tumorigenesis in other model systems, such as major excreted glycoprotein (MEP), 72-kDa gelatinase/type IV collagenase (72-kDa GEL), fibronectin (FIB), tenascin and intracellular adhesion molecule 1 (ICAM-1) is not altered in a consistent manner during in vitro transformation suppression or escape from tumorigenic and metastatic suppression. These results indicate that Krev-1 suppression of the Ha-ras-transformed/oncogenic phenotype is associated with a distinct program of gene expression changes manifested by altered rates of transcription and steady-state mRNA levels of specific oncogenic-suppressing and oncogenic-inducing genes. These data support a model of Ha-ras-induced metastasis in CREF cells that involves a direct modulation in the expression/suppression of specific combinations of oncogenic-suppressor genes and metastasis-promoting genes that are regulated coordinately in the process of tumor progression.
 ...
PMID:Defining the critical gene expression changes associated with expression and suppression of the tumorigenic and metastatic phenotype in Ha-ras-transformed cloned rat embryo fibroblast cells. 847 44

The expression of nm23-H1 has been demonstrated to be highly correlated with the metastatic potential of various tumors. In the present investigation, meningiomas of different pathological grades were used to study on their nm23-H1 expression. Immunohistochemistry showed that nm23-H1 was expressed mainly in the cytoplasm especially in the perinuclear region in explants under short-term culture. Western-blotting demonstrated the specific expression of nm23 protein in all tumor samples. The expression was also found to be sex-dependent on tumor progression in female, but not in male patients. RT-PCR results confirmed nm23-H1 expression was higher in benign tumors than in their normal counterpart. Our observations thus suggest that nm23-H1 may play an important role in the progression of meningiomas in female patients.
 ...
PMID:Expression of nm23-H1 in human meningioma cells. 941 4

It has been proposed that nm23-H1, a candidate suppressor gene for metastasis, plays an important role in the metastasis of human tumors. In order to investigate its role in the human hepatocellular carcinoma (HCC), 18 matched pairs of tumorous and adjacent nontumorous liver tissues of hepatectomy from patients with HCC were studied by quantitative reverse transcription-PCR. Further analyses of the nm23-H1 gene were also done. The results of these molecular studies were correlated with the clinicopathologic features of the patients. Nm23-H1 transcript was expressed in all neoplastic and adjacent nontumorous liver tissue. The level of expression, however, did not correlate well with the extension or metastatic potential of the tumors. Instead, in 15 (83.3%) of 18 HCC, nm23-H1 expression was higher in the tumorous tissues, compared with the adjacent nontumorous tissues; and significantly higher levels of nm23-H1 mRNA expression was detected in HCC with poor differentiation (Edmonson classification, III and IV) than those with moderate differentiation (I and II). Southern blot analysis of nm23-H1 gene revealed neither amplification nor loss of heterozygosity of all HCC tissues examined. Direct sequencing of the nm23-H1 gene in all HCC tissues detected no mutations. Our findings suggested that increased nm23-H1 mRNA expression is correlated with HCC tumor progression.
 ...
PMID:Significance of nm23 mRNA expression in human hepatocellular carcinoma. 956 75


1 2 3 Next >>