INTERACTIONS OF BIOSPECIFIC POLYMERS WITH MCF7 CELLS - MODULATION OF CELLULAR PROLIFERATION AND EXPRESSION OF ESTROGEN-RECEPTORS

Numerous studies on interactions between insoluble polymers and cell m embrane receptors indicated modulation of cellular proliferation and c ell phenotype by these polymers considered as biospecific. We synthesi zed several biospecific polymers in order to investigate the interacti ons between polymers and intracellular receptors as estrogen receptors considered as tumoral indicator of breast cancer. Biospecific polymer s were obtained by random substitutions of crosslinked polystyrene bea ds with suitable chemical groups (sulfonate and amino acid sulfamides) . These polymers were used as microcarriers for culture of MCF7 cells, a cellular model of human breast cancer. Quantification of MCF7 cell estrogen receptors was determined by radioligand binding assay for dif ferent days of cellular proliferation. The data obtained with MCF7 cel ls cultured on biospecific polymers show an inverse relationship betwe en polymer induced inhibition of cell proliferation and polymer induce d increase of estrogen receptors. Similar inverse relationship was obt ained with MCF7 cell cultured on standard polystyrene tissue culture p lates. The various interaction between insoluble polymers and MCF7 cel ls could be related to the proportion and the nature of the substituti ve chemical groups. These biospecific polymers could presents sites of interaction with cell membrane receptors leading to modulation of cel l biological activity. The different insoluble polymers were used as p reliminary models: a practical application could be a methodology of c ellular selection using soluble biospecific polymers (for example chem ically modified dextrans).