Induction Of Differentiation And Apoptosis Of HL60 Cells By Inhibiting The Biosynthesis Of Polyamine, And Associated Genes' Cloning And Expressing

Aliphatic Polyamines are natural constituents of most living organisms,They play improtant roles in regulation of cellular growth and differentiation.It was showed that abnormal increase in ornithine decarboxylase ( ODC ) activity,the key enzyme for polyamines biosynthesis, and enhanced polyamines content are closely related to carci-nogenesis,progression and metastasis of tumors. These data suggest that inhibition of polyamine biosynthesis is a efficient approach to treat tumor. Our previuos reports showed: Difluoromethylornithine ( DFMO ), a irreversible inhibitor of ODC, induced HL60 cells growth arrest and differentiatioin, and the induced cells had low or loss potential of clony formation in soft agar and tumo-rigenecity in nude mice ; And also DFMO inhibited the growth of xenograft in nude mice.To investigate the molecular mechanism of differentiation and apoptosis induced in tumor cell by inhibition of polyamine biosynthesis,and to search for the pathway of tumor therapy through inducing differentiation and apoptosis,the following experiments were accomplished:1) Construction of the cDNA library of differentiated HL60 cell induced by DFMO.2)Using differential subtraction screening, nine cDNAs were cloned, named DF1-9,they were showed only expressing in differentiated HL60 cells by Northern blotting assay.3)Construction of nine eucaryotic expressing plasmids carrying the DF1-9,named pCMV/DF1-9. 4) HL60 cells were transfected with pCMV/DFl-9,and the growth inhibition of the transfe-ctant pCMV/DF4-HL60 was observed. 5) Northern blotting assay showed that DF4 was expressed in pCMV/DF4-HL60 cell...