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)

Two recent screens for copy-number variations in the entire human genome found 12.4 gene copy number variations per person, including 2.5% of individuals with gains between 7q21.1 and 7q22.1, the chromosomal location of CYP3A4. CYP3A4 is involved in the metabolism of approximately 50% of all drugs, including many cancer chemotherapeutic agents. CYP3A4 gene copy was determined in DNA from 143 individuals: normal human livers, primary and secondary liver tumors, human hepatic cell lines, and immortalized cell lines representing eight ethnically diverse populations. CYP3A4 gene copy was normal in all but one sample, a primary human hepatocellular carcinoma cell line (TONG/HCC). Southern blots of TONG/HCC DNA revealed an approximate 10-fold increase in CYP3A and a corresponding increase in CYP3A mRNA expression and catalytic activity. Fluorescent in situ hybridization of TONG/HCC revealed specific amplification of the CYP3A4 gene on chromosome 7q21 but no amplification of the MDR1 gene that localizes 11.9 Mb upstream of CYP3A4. High resolution analysis of DNA copy number by comparative genomic hybridization confirmed amplification at 7q21.3-7q22. The amplicon spanned 1.7 Mb and contained 30 known genes, including the entire CYP3A locus. To determine whether CYP3A4 expression affected chemotherapeutic toxicity, LLC-PK1 cells were transduced with adenoviruses expressing CYP3A4 and P450 reductase. CYP3A4 conferred resistance to taxol, vinblastine and topotecan. These studies demonstrate that CYP3A4 copy number differences do not contribute to the normal variation in CYP3A4 expression. Tumors with increased CYP3A copy number (via amplification or increased chromosome 7q) would be expected to show reduced cytotoxicity to some chemotherapeutic drugs and potentially an increase in the outgrowth of drug resistant tumors.
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PMID:Increased CYP3A4 copy number in TONG/HCC cells but not in DNA from other humans. 1670 50

Multidrug resistance (MDR) phenotype is characterized by the over-expression of P-glycoprotein (P-gp) on cell plasma membranes that extrudes several drugs out of cells. Cells that express the MDR phenotype are resistant to the mitochondrial related apoptosis and to several anticancer drugs. This study assessed the presence of P-gp in mitochondria and its role in parental drug-sensitive (P5) and in P5-derived MDR1 cells P1(0.5) hepatocellular carcinoma (HCC) cell lines and in drug-sensitive (PSI-2) and mdr1-transfected (PN1A) NIH/3T3 cells. By using Western blot analysis, confocal laser microscopy, measurements of Rhodamine 123 transport across mitochondrial membranes, MDR1 small interfering RNA and flow cytometry analysis, experiments indicate that P-gp is expressed in mitochondria of P1(0.5) and PN1A cells and it is functionally active. Rho 123 accumulation was largely reduced in mitochondria of P1(0.5) cells as compared to those of P5 cells; the reduced uptake of fluorescence in mitochondria of MDR cells was due to P-gp-mediated Rho 123 efflux. In conclusion, these data demonstrate that functionally active P-gp is expressed in the mitochondrial membrane of MDR-positive cells and pumps out anticancer drugs from mitochondria into cytosol. Therefore, P-gp could be involved in the protection of mitochondrial DNA from damage due to antiproliferative drugs.
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PMID:P-gp localization in mitochondria and its functional characterization in multiple drug-resistant cell lines. 1702 68

In several neoplastic diseases, including hepatocellular carcinoma, the expression of P-glycoprotein and cyclooxygenase-2 (COX-2) are often increased and involved in drug resistance and poor prognosis. P-glycoprotein, in addition to drug resistance, blocks cytochrome c release, preventing apoptosis in tumor cells. Because COX-2 induces P-glycoprotein expression, we evaluated the effect of celecoxib, a specific inhibitor of COX-2 activity, on P-glycoprotein-mediated resistance to apoptosis in cell lines expressing multidrug resistant (MDR) phenotype. Experiments were done using MDR-positive and parental cell lines at basal conditions and after exposure to 10 or 50 micromol/L celecoxib. We found that 10 micromol/L celecoxib reduced P-glycoprotein, Bcl-x(L), and Bcl-2 expression, and induced translocation of Bax from cytosol to mitochondria and cytochrome c release into cytosol in MDR-positive hepatocellular carcinoma cells. This causes the activation of caspase-3 and increases the number of cells going into apoptosis. No effect was shown on parental drug-sensitive or on MDR-positive hepatocellular carcinoma cells after transfection with MDR1 small interfering RNA. Interestingly, although inhibiting COX-2 activity, 50 micromol/L celecoxib weakly increased the expression of COX-2 and P-glycoprotein and did not alter Bcl-x(L) and Bcl-2 expression. In conclusion, these results show that relatively low concentrations of celecoxib induce cell apoptosis in MDR cell lines. This effect is mediated by P-glycoprotein and suggests that the efficacy of celecoxib in the treatment of different types of cancer may depend on celecoxib concentration and P-glycoprotein expression.
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PMID:P-glycoprotein mediates celecoxib-induced apoptosis in multiple drug-resistant cell lines. 1751 Apr 21

Human cancers are characterized by a high degree of drug resistance. The multidrug resistance transporters MDR1-P-glycoprotein (ABCB1) and ABCC2 (MRP2) are expressed in a variety of human cancers, including hepatocellular carcinoma (HCC). The ABCC2 gene encodes a membrane protein involved in the ATP-dependent transport of conjugates of lipophilic substances. In this study we analyzed the effect of an ABCC2 antisense construct on the chemosensitization of HepG2 cells. Adenoviral vectors were constructed to allow an efficient expression of anti-ABCC2 antisense constructs. The effective target sequence comprised nucleotides 2543-2942 of the human ABCC2 cDNA. Adenoviral delivery of the ABCC2 antisense construct resulted in a reduced IC(50) for doxorubicin (12-fold), vincristine (50-fold), cisplatin (25-fold) and etoposide (VP-16) (25-fold). The adenoviral delivery of the ABCC2 antisense construct was so efficient that chemosensitization of HepG2 cells could even be demonstrated in mass cell cultures without a selection of transduced cells for single ABCC2 antisense-expressing HCC cell clones. After transfection of the ABCC2 antisense-expressing construct, HepG2 cells had significantly reduced ABCC2 mRNA and ABCC2 protein levels. Transduction of the ABCC2 antisense-expressing construct into HepG2 cells resulted in the accumulation of the high-affinity ABCC2 substrate Fluo-3. HepG2 tumors stably transfected with an anti-ABCC2 antisense construct regressed significantly in nude mice upon vincristine treatment. In addition, significant tumor regression was also observed when adenovirus-expressing anti-ABCC2 antisense construct was directly injected into HepG2 tumors in nude mice. Our study demonstrates the specific reversal of ABCC2-related drug resistance in adenovirus-transduced HepG2 cells and in HepG2 tumors in nude mice expressing this ABCC2 antisense construct.
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PMID:Reversal of drug resistance of hepatocellular carcinoma cells by adenoviral delivery of anti-ABCC2 antisense constructs. 1770 53

Cisplatin is commonly used as a chemotherapeutic agent for hepatocellular carcinoma (HCC). However, it cannot satisfactorily improve the survival rate for patients with advanced HCC due to intrinsic or acquired drug resistance caused by multidrug resistance-associated proteins (MRPs). To clarify whether or not glycyrrhizin and lamivudine have modulator effects on HCC treated with cisplatin, we established a cisplatin-resistant Huh7 HCC cell line and analyzed the mRNA expression of MRPs in the resistant cells. The resistant cells showed 14.1-fold higher resistance to cisplatin, and they expressed higher levels of MRP2 (6.29-fold), MRP3 (3.2-fold), MRP4 (11.3-fold) and MRP5 (3.39-fold) mRNAs than the wild-type cells by using real-time PCR. However, MRP1, MDR1 and GST-pi mRNA were not induced. Compared with the treatment of the resistant cells with cisplatin only, co-treatment with cisplatin and glycyrrhizin or lamivudine significantly decreased the cell viability to 76.8% and 79.5%, respectively. Co-treatment with cisplatin and both glycyrrhizin and lamivudine further decreased the cell viability to 65.1%. Intracellular concentration of cisplatin in the resistant cells decreased to 36.4% of that of the wild-type cells while it increased to 47.7% or 48.4% when glycyrrhizin or lamivudine were added separately, or 60% when they were added together. Our findings indicate the following: i) high expression of MRP2, MRP3, MRP4 and MRP5 decreases cisplatin accumulation in cisplatin-resistant HCC cells and contributes to cisplatin resistance; ii) glycyrrhizin and/or lamivudine accumulate cisplatin in resistant cells by inhibiting the cisplatin efflux from the cells; and iii) glycyrrhizin and lamivudine both act as modulators and have the effect of reversing cisplatin resistance, and co-treatment with glycyrrhizin and lamivudine enhances modulator activity in reversing the cisplatin resistance.
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PMID:The combination of glycyrrhizin and lamivudine can reverse the cisplatin resistance in hepatocellular carcinoma cells through inhibition of multidrug resistance-associated proteins. 1798 73

Tyroservatide (YSV) is an active, low-molecular-weight polypeptide that has been shown to have antitumor effects on human hepatocellular carcinoma BEL-7402 cells in vitro and in vivo. Multi-drug resistance (MDR) represents a major obstacle to the success of cancer chemotherapy. To enhance the chemosensitivity of tumor cells, attention has been focused on MDR modulators. In this study, we evaluated the reversal effect of YSV on MDR, and explored its mechanism of action in vitro. Administration of YSV reversed the multi-drug resistance of human hepatocellular carcinoma BEL-7402/5-FU cells significantly. The intracellular accumulation of doxorubicin and Rhodamine-123 (Rh123) were increased, which implied that the function of the P-glycoprotein (P-gp) efflux pump was inhibited by YSV. Moreover, the mRNA and protein expression of multi-drug resistance gene (MDR1) were also decreased by YSV. We observe that lung-resistance protein (LRP) and multi-drug resistance-associated protein (MRP1) each contribute to MDR in BEL-7402/5-FU cells as well. The mRNA and protein expression of LRP were decreased by YSV. No significant change was observed in mRNA expression of MRP1. However, we observe that the MRP1 protein level was reduced after treatment with YSV. These data demonstrate that YSV effectively reverses MDR in BEL-7402/5-FU cells, and that its mechanism of action is associated with the down-regulation of MDR1, MRP1 and LRP expression, as well as the inhibition of P-gp function.
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PMID:Reversal effect of tyroservatide (YSV) tripeptide on multi-drug resistance in resistant human hepatocellular carcinoma cell line BEL-7402/5-FU. 1853 71

Many tumors are resistant to drug-induced cell-cycle arrest and apoptosis. We have reported that apoptosis can be restored in human multidrug-resistant (MDR) hepatocellular carcinoma cell lines by celecoxib. Here we show that P-glycoprotein (P-gp) mediates cell-cycle arrest and autophagy induced by celecoxib in human MDR overexpressing hepatocellular carcinoma cell line by down-regulation of the HGF/MET autocrine loop and Bcl-2 expression. Exposure of cells to a low concentration of celecoxib down-regulated the expression of mTOR and caused G1 arrest and autophagy, while higher concentration triggered apoptosis. Cell growth inhibition and autophagy were associated with up-regulation of the expression of TGFbeta1, p16(INK4b), p21(Cip1) and p27(Kip1) and down-regulation of cyclin D1, cyclin E, pRb and E2F. The role of P-glycoprotein expression in resistance of MDR cell clone to cell-cycle arrest, autophagy and apoptosis was shown in cells transfected with MDR1 small interfering RNA. These findings demonstrate that the constitutive expression of P-gp is involved in the HGF/MET autocrine loop that leads to increased expression of Bcl-2 and mTor, inhibition of eIF2alpha expression, resistance to autophagy/apoptosis and progression in the cell-cycle. Since mTor inhibitors have been proposed in treatment of "drug resistant" cancer, these data may help explain the reversing effect of mTor inhibitors.
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PMID:Down-regulation of the HGF/MET autocrine loop induced by celecoxib and mediated by P-gp in MDR-positive human hepatocellular carcinoma cell line. 1944 20

The role of COX-2 in the regulation of the expression of MDR1, a P-glycoprotein involved in hepatocellular carcinoma cell line, HepG2, was studied in the present investigation. Celecoxib, a selective inhibitor of COX-2, at 25 microM concentration increased the accumulation of doxorubicin in HepG2 cells and enhanced the sensitivity of the cells to doxorubicin by tenfold. The induction of MDR1 expression by PGE2 and its downregulation by celecoxib or by COX-2 knockdown suggests that the enhanced sensitivity of HepG2 cells to doxorubicin by celecoxib is mediated by the downregulation of MDR1 expression, through COX-2-dependent mechanism. Further studies revealed the involvement of AP-1 in the celecoxib-induced downregulation of MDR1 expression. These experimental studies correlated well with in silico predictions and further suggested the inactivation of the signal transduction pathways involving ERK, JNK and p38. The present study thus demonstrates the usefulness of COX-2 intervention in overcoming the drug resistance in HepG2 cells.
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PMID:Celecoxib inhibits MDR1 expression through COX-2-dependent mechanism in human hepatocellular carcinoma (HepG2) cell line. 1968 55

Some membrane transporters in liver, such as P-glycoprotein, multidrug resistance-associated protein 2 (MRP2), MRP3, and MRP5 can lead to a complex multidrug resistance (MDR) to antineoplastic agents. How to inhibit these proteins is still an issue. Tetramethylpyrazine is a bioactive constituent isolated from the root of Ligusticum chuanxiong Hort, a Chinese herb. Recent studies showed that it can enhance the chemosensitivity effects of a drug on human hepatocellular carcinoma cells, acting as a multidrug resistance modulator. In this study, the reversal effect of TMP on MDR was evaluated and its activity mechanism in vitro was explored. The IC50 value shows that TMP reversed the multidrug resistance of BEL-7402/ADM cells 9.23-fold (P<0.01) at the concentration of 600 microM. The mean fluorescence intensity of ADM in BEL-7402/ADM cells with TMP was found to be 163.78+/-39.5% (P<0.01) versus in BEL-7402/ADM cells without TMP by flow cytometry and 126.73+/-28.72% in BEL-7402/ADM cells with TMP versus in BEL-7402/ADM cells without TMP (P<0.01) by high performance liquid chromatography, respectively. It was also found that the mRNA level of multidrug resistant gene MDR1, MRP2, MRP3 and MRP5 and the level of the proteins they encode were decreased after treatment with TMP, indicating that TMP can effectively reverse the MDR in BEL-7402/ADM cells, and its activity mechanism may be correlated with the down-regulation of expression in these transporters.
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PMID:Inhibition of tetramethylpyrazine on P-gp, MRP2, MRP3 and MRP5 in multidrug resistant human hepatocellular carcinoma cells. 1995 84

To study the anticancer activities of curcumin on human hepatocarcinoma cell line Sk-hep-1 and its related molecular mechanism which has not been elucidated. In the present study,we showed that curcumin inhibited proliferation of Sk-hep-1 cells in a dose-dependent manner through MTF assay. The effect of curcumin on apoptosis in Sk-hep-1 cells was investigated by DAPI staining and the various apoptosis was observed in hepatocarcinoma cell lines Sk-hep-1, HepG2 and Hep3B, but not in normal liver cell line Chang's liver with curcumin treatment. Cell cycle analysis results showed that curcumin treatment resulted in dramatic accumulation of Sk-hep-1 cells at the G0/G1 or G2/M phase. The effect of curcumin on the expression of anti-apoptosis genes (Survivin and BCl-xL) and drug resistance genes (DRG2 and MDR1) was studied by reverse transcription-polymerase chain reaction (RT-PCR). The expression of MDR1 mRNA was significantly decreased in Sk-hep-1 cells treated with curcumin, while no alterations in the amount of DRG2 and anti-apoptosis genes' mRNA levels were found. These results indicate that curcumin is able to inhibit proliferation and induce apoptosis in Sk-hep-1 cells and it may cause by down-regulating the expression of MDR1 mRNA.
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PMID:[Anticancer activities of curcumin on human hepatocarcinoma cell line Sk-hep-1]. 2045 49


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