Effects of a series of homologous α,ω‐dimethylaminoalkanes on cell proliferation: binding and uptake of putrescine by a human glioblastoma cell line (U251) in culture

Summary The first step of polyamine uptake is the binding of polyamines to the cell membrane. In order to characterize the specificity of the putrescine binding sites at the surface of the glioblastoma cells (U251), we have carried out competition experiments between putrescine bound to latex microspheres and vizualized by scanning electron microscopy and a series of N,N′ -tetramethyl- α,ω -diaminoalkanes. N,N′ -tetramethyl-1,4-butanediamine ( N,N′ -tetramethylputrescine) and higher homologs inhibit the latex putrescine binding to the cell surface and concomitantly cell proliferation. [ 14 C] putrescine uptake was mainly inhibited by the lower homologs, which were devoid of antiproliferative effects. Our results suggest that putrescine uptake by the human glioblastoma cell line U251, and putrescine binding to the surface of these cells are independent processes. The potential relationship between antitumor effect of N,N′ -tetramethyl- α,ω -diaminoalkanes and its binding to a specific putrescine acceptor site is discussed.