AIM: The expression of vascular endothelial growth factor (VEGF) and its receptors KDR and Flt-1 by gastric carcinoma tissues and different gastric carcinoma cell lines was detected to elucidate the molecular mechanis...AIM: The expression of vascular endothelial growth factor (VEGF) and its receptors KDR and Flt-1 by gastric carcinoma tissues and different gastric carcinoma cell lines was detected to elucidate the molecular mechanism of this growth factor in promoting tumor growth.METHODS: The expression of VEGF, Flt-1 and KDR was determined by reverse transcription-polymerase chain reaction (RT-PCR) in gastric cancer cell lines RF-1, RF-48,AGS-1, NCI-N87, NCI-SNU-1, NCI-SNU-5, NCI-SNU-16 and KATO-Ⅲ. The expression of Flt-1 and KDR in paraffinembedded specimens of gastric cancer was determined by immunohistochemistry. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess the role of VEGF in tumor cell proliferation.RESULTS: All 8 gastric cancer cell lines analyzed expressed VEGF121 and VEGF16s and six of them expressed both Flt-1 and KDR, while cell line NCI-SNU-5 expressed Flt-1 only and cell line KATOⅢ expressed neither Flt-1 nor KDR. The gastric carcinoma tissues expressed Flt-1 and KDR widely,with the positive rate of expression of Flt-1 and KDR being 84.6 % and 70 % respectively. The exogenous VEGF stimulated the growth of KDR-positive cell lines NCI-N87 and AGS-1 in a dose-dependent manner but exhibited no effect on the growth of KDR-negative cell line NCI-N87.CONCLUSION: VEGF and its receptors KDR and Flt-1 were expressed widely in gastric carcinoma cells and the VEGF stimulated KDR-positive tumor cell growth directly. These results suggest that VEGF may play a role in promoting tumor growth and metastasis by participating in both paracrine and autocrine pathways.展开更多
AIM:To study the interactions between human gastriccarcinoma cell (HGCC) and human vascular endothelialcell (HVEC), and the role of KDR in these interactions.METHODS:Antisense oligodexynucleotide(ASODN)specific to KDR...AIM:To study the interactions between human gastriccarcinoma cell (HGCC) and human vascular endothelialcell (HVEC), and the role of KDR in these interactions.METHODS:Antisense oligodexynucleotide(ASODN)specific to KDR gene was devised and added to theculture medium of HGCC and HVEC. After the action ofASODN, the proliferation of two cells was measured byMTT method.The role of KDR in regulating theproliferation of two kinds of cells was known throughobserving the effect of ASODN on them. The conditionedmediums (CMs) of HGCC and HVEC were prepared. TheCM of one kind of cell was added acting on the otherkind of cell, then the cell proliferation was measuredby MTT. After the action of ASODN or CM, the cellularexpression of KDR gene was detected with in situhybridization(ISH) for mRNA level and withimmunohistochemical staining for protein level. ABC-ELISA was used to detect/NEGF in the CMs of two cells.RESULTS: KDR ASODN could specifically inhibit theproliferation of HGCC and HVEC significantiy. The growthinhibitory rate amounted to 55.35 % and 54.83 %,respectively (P＜0.01). HGCC and HVEC could secret acertain level of hVEGF(92.06±1.69 ng/L, 77.70±8.04ng/L). The CM of HGCC could significantiy stimulate thegrowth(2.70±0.01 times) and KDR gene expression ofHVEC(P＜0.01) while the CM of HVEC could significantiyinhibit the growth(52.97±0.01%) and KDR geneexpression of HGCC (P ＜0.01).CONCLUSION: KDR plays a key role in regulating theproliferation of HGCC and HVEC. There existcomplicated interactions between HGCC and HVEC.HGCC can significantly stimulate the growth of HVECwhile HVEC can significantly inhibit the growth of HGCC.KDR is involved in the interactions between them.展开更多
Background:Aedes albopictus is distributed widely in China,as a primary vector of Dengue fever and Chikungunya fever in south of China.Chemical insecticide control is one of the integrated programmes to prevent mosqui...Background:Aedes albopictus is distributed widely in China,as a primary vector of Dengue fever and Chikungunya fever in south of China.Chemical insecticide control is one of the integrated programmes to prevent mosquito-borne diseases.Long-term applications of pyrethroids have resulted in the development of resistance in Ae.albopictus populations in China.However,the susceptibility of Ae.albopictus to pyrethroids in Hainan Island was unclear.Knockdown resistance(kdr),caused by point mutations in the VGSC gene,is one of the mechanisms that confer resistance to DDT and pyrethroids.This study was to investigate the resistance level of Ae.albopictus populations in Haikou City to three pyrethroid insecticides,and elucidate the relationship between the resistant phenotype and kdr mutations.Methods:The Aedes albopictus samples were collected in Xinbu Island(XI),Longtang Town(LT),Shishan Town(ST),Baishamen Park(BP),and Flower Market(FM)from Haikou City,Hainan Island,China.The larval susceptibility to deltamethrin,permethrin and beta-cypermethrin was tested by larval bioassays,and adult susceptibility to deltamethrin and DDT was determined by adult bioassays.The degree of resistance was determined by resistance ratio value(RR50>3)for larvae and by mortality for adult.The kdr alleles at codon 1534 of the VGSC gene were genotyped.The relationship between kdr genotypes and resistant phenotypes was analyzed by Chi-square test.Results:Out of five populations,assessed by larval bioassays,XI was susceptible to deltamethrin and permethrin;LT was susceptible to permethrin and beta-cypermethrin;and ST was susceptible to permithrin.FM and BP both were resistant to all of the three pyrethroids,and FM showed the highest degree of resistance,with RR50 values from 65.17 to 436.36.A total of 493 individuals from the larval bioassays were genotyped for kdr alleles.Five alleles were detected,including two wildtype alleles,TTC(F)(67.04%)and TTT(F)(0.41%),and three mutant alleles,TGC(C)(0.30%),TCC(S)(31.54%)and TTG(L)(0.71%).There was a clea展开更多
基金National Nature Science Foundation for Outstanding Young Scientist of China (to S.CC.,No.39525021)National 863 program of China (2002 AA 216111)Beijing Laboratory of Cancer Molecular Biology.
文摘AIM: The expression of vascular endothelial growth factor (VEGF) and its receptors KDR and Flt-1 by gastric carcinoma tissues and different gastric carcinoma cell lines was detected to elucidate the molecular mechanism of this growth factor in promoting tumor growth.METHODS: The expression of VEGF, Flt-1 and KDR was determined by reverse transcription-polymerase chain reaction (RT-PCR) in gastric cancer cell lines RF-1, RF-48,AGS-1, NCI-N87, NCI-SNU-1, NCI-SNU-5, NCI-SNU-16 and KATO-Ⅲ. The expression of Flt-1 and KDR in paraffinembedded specimens of gastric cancer was determined by immunohistochemistry. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess the role of VEGF in tumor cell proliferation.RESULTS: All 8 gastric cancer cell lines analyzed expressed VEGF121 and VEGF16s and six of them expressed both Flt-1 and KDR, while cell line NCI-SNU-5 expressed Flt-1 only and cell line KATOⅢ expressed neither Flt-1 nor KDR. The gastric carcinoma tissues expressed Flt-1 and KDR widely,with the positive rate of expression of Flt-1 and KDR being 84.6 % and 70 % respectively. The exogenous VEGF stimulated the growth of KDR-positive cell lines NCI-N87 and AGS-1 in a dose-dependent manner but exhibited no effect on the growth of KDR-negative cell line NCI-N87.CONCLUSION: VEGF and its receptors KDR and Flt-1 were expressed widely in gastric carcinoma cells and the VEGF stimulated KDR-positive tumor cell growth directly. These results suggest that VEGF may play a role in promoting tumor growth and metastasis by participating in both paracrine and autocrine pathways.
文摘AIM:To study the interactions between human gastriccarcinoma cell (HGCC) and human vascular endothelialcell (HVEC), and the role of KDR in these interactions.METHODS:Antisense oligodexynucleotide(ASODN)specific to KDR gene was devised and added to theculture medium of HGCC and HVEC. After the action ofASODN, the proliferation of two cells was measured byMTT method.The role of KDR in regulating theproliferation of two kinds of cells was known throughobserving the effect of ASODN on them. The conditionedmediums (CMs) of HGCC and HVEC were prepared. TheCM of one kind of cell was added acting on the otherkind of cell, then the cell proliferation was measuredby MTT. After the action of ASODN or CM, the cellularexpression of KDR gene was detected with in situhybridization(ISH) for mRNA level and withimmunohistochemical staining for protein level. ABC-ELISA was used to detect/NEGF in the CMs of two cells.RESULTS: KDR ASODN could specifically inhibit theproliferation of HGCC and HVEC significantiy. The growthinhibitory rate amounted to 55.35 % and 54.83 %,respectively (P＜0.01). HGCC and HVEC could secret acertain level of hVEGF(92.06±1.69 ng/L, 77.70±8.04ng/L). The CM of HGCC could significantiy stimulate thegrowth(2.70±0.01 times) and KDR gene expression ofHVEC(P＜0.01) while the CM of HVEC could significantiyinhibit the growth(52.97±0.01%) and KDR geneexpression of HGCC (P ＜0.01).CONCLUSION: KDR plays a key role in regulating theproliferation of HGCC and HVEC. There existcomplicated interactions between HGCC and HVEC.HGCC can significantly stimulate the growth of HVECwhile HVEC can significantly inhibit the growth of HGCC.KDR is involved in the interactions between them.
基金supported by the YM’s grant 81371848 from the National Natural Sciences Foundation of China.
文摘Background:Aedes albopictus is distributed widely in China,as a primary vector of Dengue fever and Chikungunya fever in south of China.Chemical insecticide control is one of the integrated programmes to prevent mosquito-borne diseases.Long-term applications of pyrethroids have resulted in the development of resistance in Ae.albopictus populations in China.However,the susceptibility of Ae.albopictus to pyrethroids in Hainan Island was unclear.Knockdown resistance(kdr),caused by point mutations in the VGSC gene,is one of the mechanisms that confer resistance to DDT and pyrethroids.This study was to investigate the resistance level of Ae.albopictus populations in Haikou City to three pyrethroid insecticides,and elucidate the relationship between the resistant phenotype and kdr mutations.Methods:The Aedes albopictus samples were collected in Xinbu Island(XI),Longtang Town(LT),Shishan Town(ST),Baishamen Park(BP),and Flower Market(FM)from Haikou City,Hainan Island,China.The larval susceptibility to deltamethrin,permethrin and beta-cypermethrin was tested by larval bioassays,and adult susceptibility to deltamethrin and DDT was determined by adult bioassays.The degree of resistance was determined by resistance ratio value(RR50>3)for larvae and by mortality for adult.The kdr alleles at codon 1534 of the VGSC gene were genotyped.The relationship between kdr genotypes and resistant phenotypes was analyzed by Chi-square test.Results:Out of five populations,assessed by larval bioassays,XI was susceptible to deltamethrin and permethrin;LT was susceptible to permethrin and beta-cypermethrin;and ST was susceptible to permithrin.FM and BP both were resistant to all of the three pyrethroids,and FM showed the highest degree of resistance,with RR50 values from 65.17 to 436.36.A total of 493 individuals from the larval bioassays were genotyped for kdr alleles.Five alleles were detected,including two wildtype alleles,TTC(F)(67.04%)and TTT(F)(0.41%),and three mutant alleles,TGC(C)(0.30%),TCC(S)(31.54%)and TTG(L)(0.71%).There was a clea
