AIM To compare the expression level of Fas gene and Bcl-2 gene in gastric cancer cells SGC7901 and gastric cancer MDR (multidrug resistant) cells SGC7901/VCR, to transduce Fas cDNA and Bcl-2 antisense nucleic acid int...AIM To compare the expression level of Fas gene and Bcl-2 gene in gastric cancer cells SGC7901 and gastric cancer MDR (multidrug resistant) cells SGC7901/VCR, to transduce Fas cDNA and Bcl-2 antisense nucleic acid into SGC7901/VCR cells respectively, and to observe the expression of two genes in transfectants and non-transfectants as well as their drug sensitivity.METHODS Eukaryotic expression vector pBK-Fas cDNA and pDOR-anti Bcl-2 were constructed and transfected into SGC7901/VCR cells by lipofectamine, respectively. Northern blot and Western blot were used to detect the expression of mRNA and protein in SGC7901/VCR and SGC7901 cells and transfectants, and drug sensitivity of transfectants for VCR, CDDP and 5-FU was analyzed with MTT assay.RESULTS After gene transfection, 80 for Fas and 120 for antisense Bcl-2 drug-resistant clones were selected from 2×105 cells, transfection rate being 0.04% and 0.06%. Two clones of SGC7901 Fas/VCR cells and SGC7901 anti Bcl-2/VCR cells were randomly selected for further incubation. Hybridization results showed that the expression level of Fas mRNA and protein in SGC7901/VCR cells was much lower, but that of Bcl-2 mRNA and protein was higher than that in SGC7901 cells. The expression of Fas mRNA and protein in SGC7901 Fas/VCR cells was higher, and of Bcl-2 mRNA and protein was lower in SGC7901 anti Bcl-2/VCR cells than that in non-transfectants. MTT assay showed that transfectants were more sensitive to VCR, CDDP, 5-FU than non-transfectants.CONCLUSION Bcl-2 gene displayed high expression while Fas gene had low expression in drug resistant gastric cancer cells. Expression of Bcl-2 protein was effectively blocked in SGC7901 anti Bcl-2/VCR cells by gene transfection. In contrast, the expression of Fas mRNA and protein in SGC7901 Fas/VCR cells increased. Fas gene and Bcl-2 antisense nucleic acid transfection sensitized drug resistant gastric cancer cells to chemotherapeutic drugs. These results suggest cell apoptosis plays an important role in the mechanism of MDR, and enhancing展开更多
AIM To observe the drug sensitizing effect andrelated mechanisms of fas gene transduction onhuman drug-resistant gastric cancer cellSGC7901/VCR(resistant to Vincristine).METHODS The cell cycle alteration wasobserved b...AIM To observe the drug sensitizing effect andrelated mechanisms of fas gene transduction onhuman drug-resistant gastric cancer cellSGC7901/VCR(resistant to Vincristine).METHODS The cell cycle alteration wasobserved by FACS.The sensitivity of gastriccancer cells to apoptosis was determined by invitro apoptosis assay.The drug sensitization ofcells to several anti-tumor drugs was observedby MTT assay.Immunochemical method wasused to show expression of P-gp and Topo Ⅱ ingastric cancer cells.RESULTS Comparing to SGC7901 and pBK-SGC7901/VCR,fas-SGC7901/VCR showeddecreasing G2 cells and increasing S cells,theG2 phase fraction of pBK-SGC7901/VCR wasabout 3.0 times that of fas-SGC7901/VCR,but Sphase fraction of fas-SGC7901/VCR was about1.9 times that of pBK-SGC7901/VCR,indicatingS phase arrest of fas-SGC7901/VCR.FACS alsosuggested apoptosis of fas-SGC7901/VCR,fas-SGC7901/VCR was more sensitive to apoptosisinducing agent VM-26 than pBK-SGC7901/VCR.MTT assay showed increased sensitization offas-SGC7901/VCR to DDP,MMC and 5-FU,butsame sensitization to VCR according to pBK-SGC7901/VCR.SGC7901,pBK-SGC7901/ VCRand fas-SGC7901/VCR had positively stainedTopo Ⅱ equally.P-gp staining in pBK- SGC7901/VCR was stronger than in SG07901,but there was little staining of P-gp in fas.SGC7901/VCR.CONCLUSION fas gene transduction couldreverse the MDR of human drug-resistant gastriccancer cell SGC7901/VCR to a degree,possiblybecause of higher sensitization to apoptosis anddecreased expression of P-gp.展开更多
BACKGROUND: The most common mechanisms of mul- tidrug resistance (MDR) in cancer cells is the expression of an energy-dependent exfflux pump. P-glycoprotein (P-gp) encoded by MDR1 gene and multidrug associated protein...BACKGROUND: The most common mechanisms of mul- tidrug resistance (MDR) in cancer cells is the expression of an energy-dependent exfflux pump. P-glycoprotein (P-gp) encoded by MDR1 gene and multidrug associated protein (MRP) are well known proteins associated with MDR. In human cancers, the MDR1 gene expression is common in patients with intrinsic and acquired MDR. It is a major therapeutic problem in cancer chemotherapy. Previously we found that the MDR of HCC is related to MRP gene ex- pression and initiates the intrinsic MDR. The aim of this study is to study the expression of MDR1 gene encoding P-gp and MDR1 mRNA in primary gallbladder carcinoma, and analyze its clinical significance. METHODS: Immunohistochemistry (IHC) S-P method and in situ polymerase chain reaction (ISPCR) were used to detect the expression of P-gp and MDR1 mRNA in 53 cases of untreated primary gallbladder carcinoma and 12 ca- ses of cholecystitis (archival paraffin-embedded tissues). RESULTS: The positive expression rates of P-gp and MDR1 mRNA in the 53 cases and 12 cases were 60.38%, 71.69% and 25.00%, 33.33%, respectively. There was a significant difference between the two groups (P<0.05). The positive expression rate of P-gp and MDRlmRNA were 69.44%, 83.33% and 41.18%, 47.06% respectively in tissues in stage of Nevin against Nevin , (P<0.05). In well, moderately differentiated gallbladder carcinoma tissues, their expressions were 79.49%, 69.23% against 50.00%, 35.71% in low, undifferentiated tissues (P<0.05). CONCLUSIONS: MDR to gallbladder carcinoma is closely related to the intrinsic MDR and it provides an important evidence to reverse the MDR by detection of the MDR1gene. Meanwhile, MDR1 gene expression in gallbladder carcinoma is correlated with some biological characteris- tics , takes part in the carcinogenesis of gallbladder tissues, and acts as a valuable biomarker of prognosis.展开更多
文摘AIM To compare the expression level of Fas gene and Bcl-2 gene in gastric cancer cells SGC7901 and gastric cancer MDR (multidrug resistant) cells SGC7901/VCR, to transduce Fas cDNA and Bcl-2 antisense nucleic acid into SGC7901/VCR cells respectively, and to observe the expression of two genes in transfectants and non-transfectants as well as their drug sensitivity.METHODS Eukaryotic expression vector pBK-Fas cDNA and pDOR-anti Bcl-2 were constructed and transfected into SGC7901/VCR cells by lipofectamine, respectively. Northern blot and Western blot were used to detect the expression of mRNA and protein in SGC7901/VCR and SGC7901 cells and transfectants, and drug sensitivity of transfectants for VCR, CDDP and 5-FU was analyzed with MTT assay.RESULTS After gene transfection, 80 for Fas and 120 for antisense Bcl-2 drug-resistant clones were selected from 2×105 cells, transfection rate being 0.04% and 0.06%. Two clones of SGC7901 Fas/VCR cells and SGC7901 anti Bcl-2/VCR cells were randomly selected for further incubation. Hybridization results showed that the expression level of Fas mRNA and protein in SGC7901/VCR cells was much lower, but that of Bcl-2 mRNA and protein was higher than that in SGC7901 cells. The expression of Fas mRNA and protein in SGC7901 Fas/VCR cells was higher, and of Bcl-2 mRNA and protein was lower in SGC7901 anti Bcl-2/VCR cells than that in non-transfectants. MTT assay showed that transfectants were more sensitive to VCR, CDDP, 5-FU than non-transfectants.CONCLUSION Bcl-2 gene displayed high expression while Fas gene had low expression in drug resistant gastric cancer cells. Expression of Bcl-2 protein was effectively blocked in SGC7901 anti Bcl-2/VCR cells by gene transfection. In contrast, the expression of Fas mRNA and protein in SGC7901 Fas/VCR cells increased. Fas gene and Bcl-2 antisense nucleic acid transfection sensitized drug resistant gastric cancer cells to chemotherapeutic drugs. These results suggest cell apoptosis plays an important role in the mechanism of MDR, and enhancing
基金National Natural Science Foundation of Chinese,No.3988007
文摘AIM To observe the drug sensitizing effect andrelated mechanisms of fas gene transduction onhuman drug-resistant gastric cancer cellSGC7901/VCR(resistant to Vincristine).METHODS The cell cycle alteration wasobserved by FACS.The sensitivity of gastriccancer cells to apoptosis was determined by invitro apoptosis assay.The drug sensitization ofcells to several anti-tumor drugs was observedby MTT assay.Immunochemical method wasused to show expression of P-gp and Topo Ⅱ ingastric cancer cells.RESULTS Comparing to SGC7901 and pBK-SGC7901/VCR,fas-SGC7901/VCR showeddecreasing G2 cells and increasing S cells,theG2 phase fraction of pBK-SGC7901/VCR wasabout 3.0 times that of fas-SGC7901/VCR,but Sphase fraction of fas-SGC7901/VCR was about1.9 times that of pBK-SGC7901/VCR,indicatingS phase arrest of fas-SGC7901/VCR.FACS alsosuggested apoptosis of fas-SGC7901/VCR,fas-SGC7901/VCR was more sensitive to apoptosisinducing agent VM-26 than pBK-SGC7901/VCR.MTT assay showed increased sensitization offas-SGC7901/VCR to DDP,MMC and 5-FU,butsame sensitization to VCR according to pBK-SGC7901/VCR.SGC7901,pBK-SGC7901/ VCRand fas-SGC7901/VCR had positively stainedTopo Ⅱ equally.P-gp staining in pBK- SGC7901/VCR was stronger than in SG07901,but there was little staining of P-gp in fas.SGC7901/VCR.CONCLUSION fas gene transduction couldreverse the MDR of human drug-resistant gastriccancer cell SGC7901/VCR to a degree,possiblybecause of higher sensitization to apoptosis anddecreased expression of P-gp.
文摘BACKGROUND: The most common mechanisms of mul- tidrug resistance (MDR) in cancer cells is the expression of an energy-dependent exfflux pump. P-glycoprotein (P-gp) encoded by MDR1 gene and multidrug associated protein (MRP) are well known proteins associated with MDR. In human cancers, the MDR1 gene expression is common in patients with intrinsic and acquired MDR. It is a major therapeutic problem in cancer chemotherapy. Previously we found that the MDR of HCC is related to MRP gene ex- pression and initiates the intrinsic MDR. The aim of this study is to study the expression of MDR1 gene encoding P-gp and MDR1 mRNA in primary gallbladder carcinoma, and analyze its clinical significance. METHODS: Immunohistochemistry (IHC) S-P method and in situ polymerase chain reaction (ISPCR) were used to detect the expression of P-gp and MDR1 mRNA in 53 cases of untreated primary gallbladder carcinoma and 12 ca- ses of cholecystitis (archival paraffin-embedded tissues). RESULTS: The positive expression rates of P-gp and MDR1 mRNA in the 53 cases and 12 cases were 60.38%, 71.69% and 25.00%, 33.33%, respectively. There was a significant difference between the two groups (P<0.05). The positive expression rate of P-gp and MDRlmRNA were 69.44%, 83.33% and 41.18%, 47.06% respectively in tissues in stage of Nevin against Nevin , (P<0.05). In well, moderately differentiated gallbladder carcinoma tissues, their expressions were 79.49%, 69.23% against 50.00%, 35.71% in low, undifferentiated tissues (P<0.05). CONCLUSIONS: MDR to gallbladder carcinoma is closely related to the intrinsic MDR and it provides an important evidence to reverse the MDR by detection of the MDR1gene. Meanwhile, MDR1 gene expression in gallbladder carcinoma is correlated with some biological characteris- tics , takes part in the carcinogenesis of gallbladder tissues, and acts as a valuable biomarker of prognosis.
