ABSTRACT
Objective To investigate the effects of HIF-1α expression regulated by Tet-on gene expression system on cell proliferation and cell cycle of hepatoma cells in vitro. Methods The change of human hepatocellular carcinoma cell lines HepG2 cell cycle and cell proliferation was measured after HIF-1 α expression of HepG2 in vitro was regulated by Tet-on expression system. Results Amplified products were confirmed as the cDNA of HIF-1α by DNA sequencing, and pTRE-HIF-1α obtained by edonuclease digestion,capable of expression in HepG2 Tet-on cells. After being incubated under different concentrations of doxycycline for 48 h, MTT assays showed that up-regulation of HIF-1α expression increased HepG2 cell proliferation activities. The cell index of S and G2/M phase was significantly higher and that of G0/G1 phase reduced with the increasing concentrations of doxycycline. The mRNA expression of Cyclin A increased with the increasing concentrations of doxycycline ( P ＜ 0. 001 ), CyclinD1 and CyclinE did not change ( P ＞0. 05). Conclusion HIF-1 α gene promotes cell proliferation and cell cycle of hcpatoma cells in vitro, and this effects increased with the increasing of HIF-1α expression possibly through influencing the expression of CyclinA.
ABSTRACT
The roles of multi-drug resistance protein 1 (MDR1), multi-drug resistance related protein 1 (MRP1), lung resistance protein (LRP) and breast cancer resistance protein (BCRP) in the multi-drug resistance (MDR) of hepatocellular carcinoma (HCC) were studied. By exposing HepG2 cell line to progressively increased concentrations of adriamycin (ADM), HepG2 multi-drug resistant subline (HepG2/ADM) was induced. The MDR index of HepG2/ADM was detected by using MTT.The expressions of the four MDR proteins in the three cell lines (L02, HepG2, HepG2/ADM) were investigated at mRNA and protein levels by real-time RT-PCR and Western blot respectively. Our results showed that when the ADM concentration was under 100 μg/L, HepG2 could easily be induced to be drug-resistant. The IC50 of the HepG2/ADM to ADM was 282 times that of HepG2. The expression of MDR1 and BCRP mRNA in HepG2/ADM cells were 400 and 9 times that of HepG2 cells respectively while there was no difference in the mRNA expressions of MRP1 and LRP. There was no difference between HepG2 and L02 cells in the mRNA expressions of the four genes. At the protein level, the expressions of MDR1, BCRP and LRP but MRP1 in HepG2/ADM were significantly higher than those of HepG2 and L02. Between HepG2 and L02,there was no difference in the expressions of four genes at the protein level. HepG2/ADM is a good model for the study of MDR. The four genes are probably the normally expressed gene in liven The expressions of MDR1 and BCRP could be up-regulated by anti-cancer agents in vitro. The MDR of HCC was mainly due to the up-regulation of MDR1 and BCRP but MRP1 and LRP. These findings suggest they may serve as targets for the reversal of MDR of HCC.
ABSTRACT
The roles of multi-drug resistance protein 1 (MDR1), multi-drug resistance related protein 1 (MRP1), lung resistance protein (LRP) and breast cancer resistance protein (BCRP) in the multi-drug resistance (MDR) of hepatocellular carcinoma (HCC) were studied. By exposing HepG2 cell line to progressively increased concentrations of adriamycin (ADM), HepG2 multi-drug resistant subline (HepG2/ADM) was induced. The MDR index of HepG2/ADM was detected by using MTT. The expressions of the four MDR proteins in the three cell lines (L02, HepG2, HepG2/ADM) were investigated at mRNA and protein levels by real-time RT-PCR and Western blot respectively. Our results showed that when the ADM concentration was under 100 microg/L, HepG2 could easily be induced to be drug-resistant. The IC(50) of the HepG2/ADM to ADM was 282 times that of HepG2. The expression of MDR1 and BCRP mRNA in HepG2/ADM cells were 400 and 9 times that of HepG2 cells respectively while there was no difference in the mRNA expressions of MRP1 and LRP. There was no difference between HepG2 and L02 cells in the mRNA expressions of the four genes. At the protein level, the expressions of MDR1, BCRP and LRP but MRP1 in HepG2/ADM were significantly higher than those of HepG2 and L02. Between HepG2 and L02, there was no difference in the expressions of four genes at the protein level. HepG2/ADM is a good model for the study of MDR. The four genes are probably the normally expressed gene in liver. The expressions of MDR1 and BCRP could be up-regulated by anti-cancer agents in vitro. The MDR of HCC was mainly due to the up-regulation of MDR1 and BCRP but MRP1 and LRP. These findings suggest they may serve as targets for the reversal of MDR of HCC.
ABSTRACT
0. 05). At the protein level, the expressions of MDR1, BCRP and LRP in HePG2/ADM were significantly higher than HePG2 and L02 ( FMDR1= 28. 68, FBCRP= 18. 60, FLRP= 6. 28, P 0. 05). Conclusion The four genes are probably the normally expressed genes in the liver. The expression of MDR1 and BCRP could be up-regulated by anticancer agents in vitro. MDR1 and BCRP may play very important roles in the MDR of HePG2/ADM. However, MRP1 and LRP may have no relations with the multi-drug resistance of HePG2/ ADM cell lines.
ABSTRACT
Objective To investigate the effects of Tet-on gene regulated HIF-1?expression on cell apoptosis of hepatoma cells in vitro. Methods The apoptosis of hepatocellular carcinoma cell lines HePG2 was measured after HIF-1?expression was activated in HePG2 in vitro by Tet-on expression system. Results The amplified products were confirmed as the cDNA of HIF-1?by DNA sequencing, and obtained pTHE-HIF-1?was verified by endonuclease digestion. The HePG2Tet-on cells express HIF-1?constantly. After being incubated under different concentrations of doxycycline for 48 h, HIF-1?gene could inhibit HePG2 cell apoptosis. The apoptosis rates were 59. 6%、50. 9%、38. 1%、30. 5%、23. 9%、18. 3% respectively when the concentrations of doxycycline were 0?g/ml,0. 02?g/ml,0. 2?g/ml、1?g/ml、2?g/ml,5?g/ml (P