摘要
<p><b>OBJECTIVE</b>To investigate whether multidrug resistance gene 1(mdr1) could reverse multidrug resistance (MDR) in HepG2R cells.</p><p><b>METHODS</b>An adenovirus vector, Adeno-asmdr, containing the antisense RNA driven by AFP promoter, was construct. Adeno-EGFP was transfected into HepG2, an AFP producing cell line, L02, a normal human liver cell line, and HeLa, a human cervical cancer cell line, the EGFP transcription level was detected by RT-PCR. Adeno-asmdr was transfected into HepG2R cells, the expression of P-gp170 was detected by western blotting, apoptosis was detected using TUNEL and flow cytometry, cell cycle was analyzed by flow cytometry.</p><p><b>RESULTS</b>EGFP was highly expressed in HepG2 cells, however, its expression in L02 or HeLa cells was very weak. Western blot showed that the P-gp170 was marked down-regulated 48h after transfection with Adeno-asmdr, and the expression of P-gp170 was detectable at least 7d post-transfection. Compared with control cells, Adeno-asmdr transfected HepG2R cells were more sensitive to different chemicals, as indicated by TUNEL staining and flow cytometry. Chemical treatment arrested the cells in S and G0/M phase.</p><p><b>CONCLUSION</b>The recombinant adenoviral vector, Adeno-asmdr, can block the expression of mdr1, and reverse MDR in HepG2R cells.</p>
Subject(s)
Humans , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Genetics , Metabolism , Adenoviridae , Genetics , Antineoplastic Agents , Pharmacology , Apoptosis , Carcinoma, Hepatocellular , Drug Therapy , Genetics , Metabolism , Cell Cycle , Drug Resistance, Multiple , Genetics , Drug Resistance, Neoplasm , Genetics , Gene Expression Regulation, Neoplastic , HeLa Cells , Hep G2 Cells , Liver Neoplasms , Drug Therapy , Genetics , Metabolism , RNA, Antisense , Transfection摘要
<p><b>OBJECTIVE</b>To investigate if an adenovirus vector carrying antisense multidrug resistance gene 1 (MDR1) could reverse multidrug resistance (MDR) of HepG2/ adriamycin (ADM) cells in tumors transplanted in athymic mice.</p><p><b>METHODS</b>An adenovirus vector carrying AFP promoter and antisense MDR1 was constructed. HepG2 MDR cells (HepG2/ADM) were induced by graded resistance to ADM and were subcutaneously inoculated into athymic mice to construct the transplanted tumor. After adeno-asmdr1 was injected, the volume of the transplanted tumor and the apoptotic body in the xenograft tumor cells were observed and reverse transcriptase polymerase chain reaction was employed to investigate the expression of the mdr1-mRNA from the mouse transplanted tumor cells.</p><p><b>RESULTS</b>Following injection with adeno-asmdr1, the tumor volumes in this mice group did not increase. However the tumor volume in the PBS plus ADM group did increase significantly (P less than 0.05). In the tumor xenograft cells, mdr1 mRNA in the xenografts was assessed by RT-PCR and found to be reduced at week 1, and at week 4 in the ADM+asmdr1 group, but it was stable in the ADM group. It was only 20% in the ADM+asmdr1 group compared to the ADM group at the 4th week. Evidence of apoptosis was observed in the tumor xenograft cells treated with adeno-asmdr1, but there was rarely any apoptosis in the group treated with ADM and PBS.</p><p><b>CONCLUSION</b>Adenovirus carrying antisense mdr1 RNA can partially reverse the MDR of HepG2/ADM cells and inhibit tumor growth by down-regulating mdr1 mRNA resulting in tumor cell apoptosis.</p>
Subject(s)
Animals , Humans , Male , Mice , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Genetics , Adenoviridae , Genetics , Carcinoma, Hepatocellular , Drug Therapy , Cell Line, Tumor , Doxorubicin , Pharmacology , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Genetics , Genetic Vectors , Hep G2 Cells , Mice, Inbred BALB C , Mice, Nude , RNA, Antisense , Genetics摘要
<p><b>OBJECTIVE</b>To study the epidemiological characteristics and preventive methods of road traffic crashes in a mountain city in western China through sampling investigation of traffic crashes in different regions of Chongqing city in recent years.</p><p><b>METHODS</b>Two police teams of traffic management in downtown, two teams in suburb, one team in county and one freeway team were randomly selected, and road traffic crashes between 1988 and 1997 were investigated and analyzed.</p><p><b>RESULTS</b>A total of 13121 road traffic crashes with 6201 crashes with casualties were analyzed. The incidence of crashes was higher in May, June and July, and on Friday and Wednesday and at 8:00-12:00 and 14:00-18:00 within a day. Casualties were 44.0% in pedestrians and 42.5% in passengers of total casualties. The deaths and severe injuries in pedestrians were 59.1% of total deaths and 56.4% of total severe injuries. The age of drivers and passengers were mainly at 18-30 years, followed by 31-40 years. People over 60 years old accounted for 24.1% of total pedestrian casualty. Head injury was the most common reason for deaths. The main reasons for these crashes were improper driving and violating traffic laws. Violating traffic laws by pedestrian was one of the main reasons for pedestrian casualty.</p><p><b>CONCLUSIONS</b>The crashes are related to the characteristics of geography, climate, society activity of people, and the sense of traffic safety, the basic traffic construction and management in Chongqing. The traffic casualty of pedestrian is a big problem in Chongqing. To prevent and decrease road traffic injuries effective methods should be worked out and propaganda on traffic safety and traffic management should be strengthened according to different characteristics of different regions. To strengthen the first aid and treatment of cranium-brain injury and chest-back injury is also helpful in decreasing traffic deaths.</p>