AIM: To explore whether antisense blocking of protein kinase C alpha (PKCalpha) would reverse multi-drug resistance (MDR) in the vincristine (VCR)-resistant human gastric cancer cell line SGC7901/VCR. METHODS: SGC7901/VCR cells expressing antisense PKCalpha, SGC7901/VCR/aPKC, were established by transfection with a recombinant plasmid reversely inserted with PKCalpha cDNA. Empty vector (PCI-neo)-transfected cell clones, SGC7901/VCR/neo, served as the control. Western blot method was used to detect PKCalpha content in SGC7901, SGC7901/VCR, SGC7901/VCR/neo and SGC7901/VCR/aPKC cells, using PKCalpha-specific antibody. The sensitivity of SGC7901, SGC7901/VCR, SGC7901/VCR/neo and SGC7901/VCR/aPKC cells to doxorubicin (DOX) in vitro was determined by MTT assay. The uptake of DOX in these cells was detected with fluorescence spectrophotometer. RESULTS: Western blot analysis showed that the PKCalpha protein level was about 8.7-fold higher in SGC7901/VCR cells than that in SGC7901 cells, whereas the protein expression of PKCalpha was reduced by 78% in SGC7901/VCR/aPKC cells when compared with the SGC7901/VCR cells. SGC7901/VCR/aPKC cells had a 4.2-fold increase in DOX cytotoxicity, accompanied by a 1.7-fold increase of DOX accumulation in comparison with SGC7901/VCR cells. CONCLUSION: PKCalpha positively regulates MDR in SGC7901 cells, and inhibition of PKCalpha can partially attenuate MDR in human gastric cancer cells.
AIM: To explore whether antisense blocking of protein kinase C alpha (PKCalpha) would reverse multi-drug resistance (MDR) in the vincristine (VCR)-resistant humangastric cancer cell line SGC7901/VCR. METHODS: SGC7901/VCR cells expressing antisense PKCalpha, SGC7901/VCR/aPKC, were established by transfection with a recombinant plasmid reversely inserted with PKCalpha cDNA. Empty vector (PCI-neo)-transfected cell clones, SGC7901/VCR/neo, served as the control. Western blot method was used to detect PKCalpha content in SGC7901, SGC7901/VCR, SGC7901/VCR/neo and SGC7901/VCR/aPKC cells, using PKCalpha-specific antibody. The sensitivity of SGC7901, SGC7901/VCR, SGC7901/VCR/neo and SGC7901/VCR/aPKC cells to doxorubicin (DOX) in vitro was determined by MTT assay. The uptake of DOX in these cells was detected with fluorescence spectrophotometer. RESULTS: Western blot analysis showed that the PKCalpha protein level was about 8.7-fold higher in SGC7901/VCR cells than that in SGC7901 cells, whereas the protein expression of PKCalpha was reduced by 78% in SGC7901/VCR/aPKC cells when compared with the SGC7901/VCR cells. SGC7901/VCR/aPKC cells had a 4.2-fold increase in DOXcytotoxicity, accompanied by a 1.7-fold increase of DOX accumulation in comparison with SGC7901/VCR cells. CONCLUSION:PKCalpha positively regulates MDR in SGC7901 cells, and inhibition of PKCalpha can partially attenuate MDR in humangastric cancer cells.