Effect of natural beta‐interferon on cell proliferation and steroid receptor level in human breast cancer cells

Abstract

The effect of natural beta‐interferon (β‐IFN) on cell proliferation and steroid receptor level was investigated in CG‐5 human breast cancer cell line. β‐interferon determines an appreciable diminution of cell growth, at concentrations ranging from 100 to 1000 IU/ml, which is enhanced when serum content of the culture medium is lowered. Low concentrations of β‐IFN (10–100 IU/ml) produce, after a 5‐day treatment, an increase in estrogen receptors (ER) and progesterone receptors (PR). No variation of ER and PR levels is observed when β‐IFN is added directly to the cell homogenate before the assay. Our data suggest that β‐IFN could affect hormone sensitivity through a modification of ER and PR in neoplastic mammary cells. Copyright © 1987 American Cancer Society