Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have recently shown that acetaminophen induces many of the apoptotic traits in hepatoma cells and lymphocytes (Boulares et al. (2002d). In an effort to further investigate the mechanism by which non-metabolized acetaminophen induces apoptosis, we have now examined the roles of caspase-3, the DNA fragmentation factor, and the poly(ADP-ribose) polymerase-1-regulated Ca2+ and Mg2+-dependent endonuclease DNAS1L3 in the induction of such death process. This was achieved with the use of MCF-7 cells, a caspase-3-deficient breast adenocarcinoma cell line, thymocytes isolated from DFF45 (the inhibitory and chaperone subunit of the DNA fragmentation factor subunit, DFF40) deficient mice, and HeLa cells, a DNAS1L3-deficient cervical carcinoma cell line. MCF-7 exhibited a marked resistance to acetaminophen treatment. Ectopic expression of human caspase-3 significantly potentiated the cytotoxic effect of acetaminophen and promoted the release of cytochrome c into the cytosol of treated cells suggesting a direct role for caspase-3 in acetaminophen-induced apoptosis. Expression and cleavage of DFF45 were required but not sufficient for acetaminophen-induced internucleosomal DNA fragmentation. DFF45 gene knockout rendered thymocytes resistant against acetaminophen-induced generation of both large and internucleosomal DNA fragments. The treatment of HeLa cells with acetaminophen resulted in internuclesomal DNA fragmentation only after transfection of these cells with a plasmid encoding the DNAS1L3 gene suggesting that this endonuclease is required for acetaminophen-induced internucleosomal DNA fragmentation. DNAS1L3 expression potentiated the cytotoxic effect of acetaminophen in HeLa cells suggesting an active role in the death process induced by this drug. Altogether, these results demonstrate the specific roles of caspase-3, DNA fragmentation factor, and DNAS1L3 in the process of acetaminophen-induced apoptosis in cultured cells.
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PMID:Mechanism of acetaminophen-induced apoptosis in cultured cells: roles of caspase-3, DNA fragmentation factor, and the Ca2+ and Mg2+ endonuclease DNAS1L3. 1472 11

To explore the change of sensitivity to chemotherapy of antisense RNA targeting survivin on hepatocarcinoma carcinoma cells in vitro. Survivin mRNA structure region was amplified by RT-PCR and inserted inversely into eukaryotic expression vector pcDNA3. The antisense expression plasmid pcDNA3/survivin was transfected into HepG2 with lipofectAMINE 2000 (LF2000), with low concentration of 5-fluorouracil (5-Fu) added. Survivin protein was detected by Western-blot, the growth activity was measured by MTT, and apoptosis was detected by Flow Cytometry 12 h, 24 h, 48 h after transfection. The activity of caspase-3 was found by quantitative assay 48 h after transfection. The construction of antisense RNA vector pcDNA3/survivin was verified by restricted endonuclease digestion and nucleotide sequencing. Compared with normal group, 5-Fu and antisense survivin group, the cells growth inhibition, apoptosis index, and caspase-3 activity were increased in antisense survivin transfected + 5-Fu group. The threshold of apoptosis was decreased after survivin was silenced, and the sensitivity to chemotherapy was increased. These findings suggest the existence of a potential new target for gene therapy.
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PMID:An antisense plasmid targeting survivin expression induces apoptosis and sensitizes hepatocarcinoma cells to chemotherapy. 1501 43

Integrated hepadnaviral DNA in livers and tumors of chronic hepatitis B patients has been reported for many years. In this study, we investigated whether hepatitis B virus DNA integration occurs preferentially at sites of cell DNA damage. A single I-SceI homing endonuclease recognition site was introduced into the DNA of the chicken hepatoma cell line LMH by stable DNA transfection, and double-strand breaks were induced by transient expression of I-SceI after transfection of an I-SceI expression vector. Alteration of the target cleavage site by imprecise nonhomologous end joining occurred at a frequency of approximately 10(-3) per transfected cell. When replication of an avian hepadnavirus, duck hepatitis B virus, occurred at the time of double-strand break repair, we observed integration of viral DNA at the site of the break with a frequency of approximately 10(-4) per transfected cell. Integration depended on the production of viral double-stranded linear DNA and the expression of I-SceI, and integrated DNA was stable through at least 17 cell divisions. Integration appeared to occur through nonhomologous end joining between the viral linear DNA ends and the I-SceI-induced break, because small deletions or insertions were observed at the sites of end joining. The results suggest that integration of hepadnaviral DNA in infected livers occurs at sites of DNA damage and may indicate the presence of more widespread genetic changes beyond that caused by viral DNA integration itself [corrected].
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PMID:Genomic DNA double-strand breaks are targets for hepadnaviral DNA integration. 1525 90

To express the extracellular fragement of hepatoma associated antigen HAbl8G(HAb18GEF) in E. coli efficiently in a non-fusing way, the cDNA of HAb18GEF gene was inserted into prokaryotic expression vector pET21a + . The secondary structure and codon adaptation of translational initiation region (TIR, from-30 to + 39) in mRNA of recombinant vector HAb18GEF/ pET21a + was predicted simultaneously by computer-aided design. Stable Stem-Loop structures and many low-usage codons were detected in mRNA-TIR of non-optimized recombinant HAb18GEF/pET21a + vector. The stability of mRNA-TIR in recombinant HAb18GEF/pET21a + vector was reduced with following methods: (1) optimization of secondary structure (2) optimization of codon adaptation. These optimization were realized by non-continual site-directed mutagenesis without changing any amino acid sequence in TIR. After being checked through restriction endonuclease digestion and confirmed through nucleotide sequencing, the pre-optimized and post-optimized recombinant vectors were transformed into competent E. coli JM109-DE3. The resulted recombinant clones were selected randomly and induced by IPTG at 37 degrees C. The induced production of these recombinants was analyzed by SDS-PAGE, indirect ELISA, Western blot, and cell fractionation assay. The amount of HAb18GEF mRNA was also detected by RNA dot blot between pre-optimized recombinant and post-optimized recombinant. The results revealed that recombinant non-fused vectors HAb18GEF/pET21a + were successfully constructed and optimized in the secondary structure and codon adaptation of TIR respectively. The HAb18GEF was expressed efficiently in a non-fusing way in recombinant E. coli by secondary structure optimization or codon adaptation optimization. Whereas, no expression of HAb18GEF was detected in pre-optimized recombinants. The non-fused expression products-HAb18GEF, mainly as inclusion body in E. coli, yielded highly above 29.3%. A trait of expression HAb18GEF was also detected both in intermembrane space and in culture medium due to over-expression and cell leakage. Difference in non-fused expression level of HAb18GEF between secondary structure optimization and codon adaptation optimization was negligible. No difference in amount of transcribed mRNA of HAb18GEF between the pre-optimized and the post-optimized recombinants was detected. To sum up, it's feasible to express hepatoma associated antigen HAb18GEF in a non-fusing way by reducing the stability of TIR in mRNA.
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PMID:[Non-fused expression of HAb18GEF by reducing stability of translational initiation region in mRNA]. 1596 4

Nucleotide sequence analysis of the left end of the genome of fowl adenoviruses (FAdV) representing species group C (FAdV-4 and -10), D (FAdV-2) and E (FAdV-8) were carried out, and the sequence data was compared to those of FAdV-1 (FAdV-A) and FAdV-9 (FAdV-D). The viruses were propagated in chicken hepatoma cell line for viral DNA isolation. Restriction endonuclease analysis was performed followed by hybridization with two DNA probes representing the left end of FAdV-9. The identified fragments were sequenced, and the generated data were compared with the GenBank database. Nucleotide sequence homology and amino acid sequence identities were high between members of the same species group, FAdV-2 and -9, and FAdV-4 and -10, whereas different degrees of variations were observed among all FAdVs. Gene arrangement and position of ORFs at the left end of FAdV genomes were largely conserved suggesting similar gene functions. All previously characterized left end ORFs in CELO virus and FAdV-9 were found in all analyzed FAdVs. However, ORF 1C was absent in FAdV-4 and -10, but additional ORFs, most likely corresponding to duplicates of ORF 14, were observed in these viruses.
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PMID:Sequence analysis of the left end of fowl adenovirus genomes. 1679 24

Apurinic apyrimidinic endonuclease (APE1)/redox effector factor 1 (Ref-1), which is a multifunction protein involved in both transcriptional regulation of gene expression during adaptive cellular responses to oxidative stress and in the base excision repair pathway of DNA lesions generated as a consequence of oxidant-induced base damage, contributes to the maintenance of genome stability. APE1/Ref-1 is normally localized in the nucleus; cytoplasmic localization observed in several tumors has been correlated with a poor prognosis. Hepatocellular carcinoma (HCC) grading is an essential tool to predict the risk of relapse and patient prognosis, particularly in patients undergoing liver transplantation (OLT). The aim of this study was to identify the role of APE1/Ref-1 in predicting a posttransplant HCC relapse. We studied 48 patients transplanted for HCC to define grading as well as nuclear and cytoplasmic APE1/Ref-1 expression within neoplastic versus nonneoplastic parenchyma. We defined a cutoff of 60% of cytoplasmic APE1/Ref-1 expression to identify positive cases. At a minimum of 1.5-year follow-up after transplantation, 32 patients are alive and 16 patients are deceased after HCC relapse. Among low-grade HCC (grades 1 and 2), 76% of cases are alive; only 34% showed cytoplasmic APE1/Ref-1 immunoreactivity. Among the high-grade cases (grades 3 and 4), 50% were alive with 64% showing cytoplasmic immunoreactivity. Nuclear reactivity was generally similar either in neoplastic or in cirrhotic livers, irrespective of the grade. These data seemed to support the hypothesis of a predictive role of APE1/Ref-1 for HCC risk of relapse, which together with tumor grade by analysis of a pretransplant needle biopsy should aid decision making for OLT.
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PMID:Apurinic apyrimidinic endonuclease/redox effector factor 1 immunoreactivity and grading in hepatocellular carcinoma risk of relapse after liver transplantation. 2053 62

Hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) is one of the most frequently occurring cancers. Hepadnaviral DNA integrations are considered to be essential agents which can promote the process of the hepatocarcinogenesis. More and more researches were designed to find the relationship of the two. In this study, we investigated whether HBV DNA integration occurred at sites of DNA double-strand breaks (DSBs), one of the most detrimental DNA damage. An 18-bp I-SceI homing endonuclease recognition site was introduced into the DNA of HepG2 cell line by stable DNA transfection, then cells were incubated in patients' serum with high HBV DNA copies and at the same time, DSBs were induced by transient expression of I-SceI after transfection of an I-SceI expression vector. By using nest PCR, the viral DNA was detected at the sites of the break. It appeared that integration occurred between part of HBVxgene and the I-SceI induced breaks. The results suggested that DSBs, as the DNA damages, may serve as potential targets for hepadnaviral DNA insertion and the integrants would lead to widespread host genome changes necessarily. It provided a new site to investigate the integration.
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PMID:DNA double-strand breaks, potential targets for HBV integration. 2055 66

The persistence of covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) in hepatocytes plays a key role in viral persistence and resistance to therapy. Therefore, quantitative cccDNA measurement is of clinical importance for evaluating the efficacy of antiviral drugs, selecting an appropriate treatment strategy, and predicting the prognosis. Current established methods for measurement of cccDNA need further improvement. A modified method was developed using digestion with restriction endonucleases that do not recognize sites in the HBV DNA and plasmid-safe ATP-dependent DNase (PSAD), and using a cccDNA-specific primer set in a real-time PCR reaction. The cccDNA-specific primer has a similar amplification efficiency as a commercial kit. Treatment of samples with restriction endonuclease followed by PSAD digestion increased significantly the specificity of a cccDNA-selective primer set compared with other treatments (P<0.05). Analysis of 35 serum and liver DNA samples from patients with hepatocellular carcinoma demonstrated that the amount of serum cccDNA is beyond the minimum detection limit and that the liver cccDNA quantity is about 0-49.2 copies/cell, consistent with previous reports. Taken together, this method has the potential for evaluating the efficacy of antiviral drugs.
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PMID:Enhanced specificity of real-time PCR for measurement of hepatitis B virus cccDNA using restriction endonuclease and plasmid-safe ATP-dependent DNase and selective primers. 2069 34

The rat hepatoma cell line (2sFou) was used to assess the mechanism of DNA strand breakage using the model oxidant H(2)O(2). Exposure of the cells to H(2)O(2) (100 mum) at 37 degrees C significantly reduced the amount of double-stranded DNA remaining after alkaline unwinding at 15 degrees C (control = 75.0 +/- 7.3%, n = 9, 100 mum H(2)O(2) = 46.5 +/- 8.0, n = 8, P < 0.02). The catalase inhibitor 3-amino-1,2,4-triazole halved the concentration of H(2)O(2) needed to give a significant level of strand breakage (control = 58.6 +/- 3.9%, n = 8, 50 mum H(2)O(2) = 36.5 +/- 2.1, n = 3, P < 0.02). The calcium chelator Quin-2 and the endonuclease inhibitor aurintricarboxylic acid both inhibited DNA strand breakage following treatment with 100 mum H(2)O(2) by 92% and 94%, respectively, whereas the lipid peroxidation inhibitor N, N-diphenyl-1,2,4-phenylene-diamine had no effect on H(2)O(2)-induced strand breakage. Analysis of the 2sFou cellular DNA for the 8-oxodG adduct following H(2)O(2) exposure provided no evidence for direct attack of the DNA mediated by hydroxyl radicals. Ca(2+) appears to be the major mediator of H(2)O(2)-induced DNA strand breakage.
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PMID:Relative importance of oxidation and Ca(2+) in DNA strand breakage by H(2)O(2) in the 2sFou cell line. 2069 86

The Mus81 gene encodes a critical endonuclease involved in DNA repair and tumor suppression. Our previous study has shown reduced expression of Mus81 in hepatocellular carcinoma and its association with the metastatic potential and prognosis of hepatocellular carcinoma. However, the role of Mus81 in colorectal carcinoma is currently unknown. We therefore carried out the present study to explore the correlation between Mus81 expression and the progression of colorectal carcinoma. Mus81 expression in 92 cases of colorectal carcinoma and matched normal tissues was determined by quantitative real-time polymerase chain reaction. Our results showed that Mus81 expression in colorectal carcinoma tissues was significantly reduced compared with the corresponding normal tissues (P < 0.001) and the downregulation of Mus81 (decreased by more than 50%) was found in 60.9% (56/92) of colorectal carcinoma. Moreover, Mus81 downregulation correlated significantly to hepatic metastasis (P = 0.019) and a high TNM stage (P = 0.025) of colorectal carcinoma. In addition, the decrease of Mus81 was also detected in 10 cases of hepatic metastasis tissues compared with the corresponding primary colorectal carcinoma tissues (P = 0.016). More importantly, colorectal carcinoma patients with apparent Mus81 downregulation have shown significantly poorer overall survival than those with little Mus81 downregulation (P = 0.0374). Also, multivariable Cox regression analysis identified Mus81 downregulation as an independent prognostic factor for colorectal carcinoma (hazard ratio, 1.678; P = 0.040). In conclusion, the reduced expression of Mus81 is closely related to hepatic metastasis and poor prognosis of colorectal carcinoma, indicating Mus81 as a novel prognostic marker for colorectal carcinoma.
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PMID:Downregulation of Mus81 as a novel prognostic biomarker for patients with colorectal carcinoma. 2117 91


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