Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0345904 (liver cancer)
 15,188 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transfection assay of NIH 3T3 cells was performed with DNAs isolated from ten human PHC (primary hepatic cancer) specimens and a hepatoma 7402 cell line. Positive results were obtained in 7402 and in six out of ten PHC DNAs. Human N-ras gene was identified in transfectants from 7402 DNA and transformed cells from three PHC DNA samples, which had passed more than two cycles of transfection. The expression of N-ras was also remarkably enhanced in six out of nine poly(A)+RNA samples isolated from PHC tissues. P21 synthesis was elevated in 7402 cells as well as in transfectants derived from 7402 cells and PHC DNA. In analysis of PHC DNA, rearrangement and amplification of N-ras gene was observed in two PHC samples. The discrepancy of results of the transfection assay and mRNA expression was discussed. Furthermore, c-myc was also highly expressed in most PHC tissues. It implied that the cooperating activity of N-ras and c-myc might be responsible for the malignant phenotypic alteration in some or most cases in human primary liver cancer.
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PMID:Oncogenes in human primary hepatic cancer. 242 30

It is now evident that development of hepatocellular carcinoma (HCC) in human is associated with a long series of cellular and tissue changes that precede the ultimate development of the cancer. During recent years, enormous progress in molecular research on HCC has been made, particularly in the area of integration of HBV DNA to host cell and oncogene association with carcinogenicity. A high ratio of HCCs from patients in endemic area has integrated HBV DNA in cellular DNA and in some cases, chromosomal translocations associated with HBV integration were observed, suggesting that the integration or the results thereof are connected with cancer development. Employing a DNA-mediated transfection assay using NIH3T3 mouse fibroblasts with high molecular weight DNA, we detected three cellular transforming genes (lca, N-ras, hst) in primary human HCC. However, little is known as to the linkage between the activation of these genes and liver carcinogenesis. In most human primary HCC tissues, at least two oncogenes, c-myc and N-ras are overexpressed, while in some cases other oncogenes c-fos or lca are overexpressed. It is likely that multiple c-oncogens are important in HCC, but specific transcripts for the malignancy of HCC were not detected. At present, we could not find any relationship between the expression of c-oncogenes and integration of HBV, serological markers or the degree of differentiation. Of the experimental animals most frequently used for studies of liver cancer, the rat is best understood and mimics closely many of the lesions in humans. It is of interest to consider that the identification and elucidation of the mechanisms underlying carcinogenic processes in the rat may offer testable hypotheses for steps in the human.
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PMID:[Molecular aspects of human hepatocellular carcinoma]. 253 67

Chinese medicinal herbs with Jian Pi Li Qi action were tested for their effects in inhibiting the precancerous lesions, gamma-GT positive hepatocellular foci and the expression of oncogenes (N-ras, Ha-ras) in male SD rats. The rats were given one i.p. dose of initiator DEN within 24 hours after 2/3 partial hepatectomy. The livers of sacrificed rats were processed to gamma-GT histochemical staining and measuring of oncogenic expression. The results of these two parameters showed that Chinese medicinal herbs with Jian Pi Li Qi action are effective in inhibiting the precursory lesions of liver cancer in rats.
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PMID:[Inhibitory effects of jian pi li qi Chinese medicinal herbs on diethylnitrosamine (DEN)-induced hepatocarcinogenesis in rats]. 267 88

The transfection of NIH 3T3 cells was performed with DNAs from 2 duck primary hepatic carcinomas (DHC 40K, 9K) and 1 tumor-adjacent liver tissue (TAL, 9N). Transfectants were found from 40K, 9K and 9N DNAs. The secondary transfectants were obtained after transfection of RAT-1 cells with DNAs from primary transfectants. After hybridization with Ha-ras, Ki-ras, N-ras and mht oncogenes, it was found that duck mht (5.2 and 3.2 kb EcoRI fragments) and duck Ha-ras (3.4 kb EcoRI fragments) were present in all these transformants. This is the first report on transforming genes in duck primary hepatic cancer as well as tumor-adjacent liver tissue.
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PMID:Transforming genes in duck hepatic carcinoma--mht(raf) and Ha-ras. 285 57

DNA was extracted from NIH 3T3 cells transformed with DNAs from human primary hepatic cancer (PHC) and Hepatoma 7402 cell line. The transformant DNA was analyzed by Southern transfer and hybridization with 32P-labeled probes of various oncogenes. The EcoRI 7.2 and 9.0 kb bands characteristic of human N-ras gene were identified in transformed NIH 3T3 cells derived both from PHC and 7402 DNA. The BamHI 6.6 kb band characteristic of human c-Ha-ras I was present only in 7402 transformants, but not in PHC transformants. Using 35S-methionine incorporation, immunoprecipitation with anti-p21 monoclonal antibodies, SDS-PAGE and autoradiography, it was demonstrated that p21 synthesis was remarkably enhanced in 7402 cells as well as in transformed cells derived from both 7402 and PHC DNA. Taking the data together, it strongly implies that N-ras is one of the transforming genes for human liver cancer.
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PMID:Identification of human N-ras as the common oncogene in NIH 3T3 cells transformed with DNAs from human primary hepatic cancer and hepatoma 7402 line. 301 22

Poly(A)+ RNA was isolated from 9 specimens of human primary hepatic carcinoma, 1 non-tumorous liver tissue adjacent to cancer and 1 normal liver tissue samples. The Oligo-dT cellulose-purified poly(A)+ RNAs were subjected to formaldehyde agarose gel electrophoresis, Northern transfer and hybridization with various oncogene probes. Two RNA species, 5.6 kb and 2.2 kb were identified by N-ras gene hybridization in 6 out of 9 mRNA samples from primary hepatic carcinoma specimen. N-ras specific mRNA was not detectable in mRNA samples from normal human liver and tumor surrounding cirrhotic tissue. No detectable hybridization of mRNA from hepatoma and normal liver with Ki-ras or Ha-ras was observed. As human N-ras gene has been identified in DNA of mouse transfectants transformed with PHC DNA, it strongly suggests that N-ras gene might be responsible for the transforming activity of part of cases of human liver cancer.
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PMID:Expression of N-ras gene in human primary hepatocarcinoma. 301 23

Liver cancer is one of the most prevalent forms of cancer in the world. Hepatitis B virus (HBV) is considered to be a major aetiological factor. Evidence from epidemiological studies has also indicated that environmental contaminants such as mycotoxins may, either in combination with HBV or independently, be important aetiological factors in the pathogenesis of primary hepatocellular carcinoma (PHC). Laboratory data also suggest an interplay between viral and chemical factors in the multifactorial aetiology of PHC. Aflatoxin B1, the chemical carcinogen most frequently implicated in the aetiology of hepatocellular carcinoma is a procarcinogen that must be activated by mixed-function oxidases to an electrophilic metabolite before it can exert its carcinogenic effects. Interindividual differences (greater than 10-fold) in the metabolic activation of aflatoxin B1 are observed. These differences may play a part in an individual's oncogenic susceptibility to aflatoxin B1. Chemical carcinogens and integrated HBV may activate cellular oncogenes, eg N-ras, and inactivate tumour suppressor genes. Recently developed methods that allow monitoring of aflatoxin B1 and HBV exposures and also genetic damage caused by these agents in individuals should help in biochemical and molecular epidemiological studies concerning the aetiology of hepatocellular carcinoma. We identify areas of uncertainties and of future experimentation and propose a hypothesis of liver carcinogenesis.
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PMID:Interactive effects of chemical carcinogens and hepatitis B virus in the pathogenesis of hepatocellular carcinoma. 304 Feb 43

In order to investigate the action of oncogenes in experimental hepatocarcinogenesis, the expression of c-myc, N-ras and H-ras were studied during early and late stages of DENA induced hepatocarcinogenesis in rats by using in situ hybridization. The results showed that overexpression of c-myc and N-ras was presented in teh proliferation hepatocytes and alternated hepatocytes foci during the early stage of hepatocarcinogenase, and with the formation and progression of hyperplastic hepatocytic nodules, the overexpresion cells of both were increased and often accompanied each other. Overexpression of H-ras appeared in the middle stage of hepatocarcinogenesis. The data obtained indicate that the abnormal expression of N-ras and c-myc in the hepatocarcinogenesis is not only an earlier molecule event which may relate to the initiation of HCC, but also the molecular basis for the morphogenesis of HCC, and these two functions took synergically. However, the abnormal expression of H-ras may have a promotive effect on the development of preneoplastic lesions, and also suggests that the malignant transformation of hepatocyte needs the cooperation of multiple oncogenes.
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PMID:[In situ expression of c-myc, N-ras during diethylnitrosamine induced hepatocarcinogenesis]. 874 81

The regulating effects of TCM treatments including clearing away heat and toxic materials, promoting blood circulation and removing blood stasis, and strengthening the spleen and regulating qi on the oncogene transcription were observed in the liver cancer model rats. The preliminary results indicated that the mRNA levels of H-ras N-ras and K-ras, and signal molecules correlated with the ras/MAPK signal transduction pathway were down-regulated by the different TCM treatments in varying degrees. Also, the regulating effects of the treatments on differently-displayed genes were discrepant. It is suggested that the molecular mechanisms of the TCM treatments for liver cancer was complex with different target genes.
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PMID:Preliminary investigation on regulating effects of different TCM treatments on transcription of the correlated genes of liver cancer in rats. 1274 7

Microcystin-LR (MC-LR) is the most common and toxic hepatotoxin and it could induce human hepatitis and hepatocellular carcinoma (HCC) via the route of drinking water. The aim of the present study was to determine the expressions of oncogenes c-fos, c-jun, c-myc, c-met, and N-ras and tumor suppressor gene PTEN in HepG2 cells following MC-LR-exposure to understand the possible mechanism of MC-LR-related human primary liver cancer. The results of qPCR and Western blotting showed that MC-LR-exposure at non- or sub-cytotoxic concentrations promoted the expressions of oncogenes c-fos, c-jun, c-myc, c-met, and N-ras while suppressed tumor-suppressor gene PTEN in HepG2 cells at both transcription and protein levels. This result suggests that HCC-related genes may be involved in human hepatitis and primary liver cancer caused by MC-LR. The work might be useful for evaluating the human health risk resulted from the long-term of MC-LR-exposure at low dose via drinking water route.
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PMID:Alterations in transcription and protein expressions of HCC-related genes in HepG2 cells caused by microcystin-LR. 2806 58


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