Glucocorticoids enhance viral transformation of mammalian cells.

The effect of glucocorticoids on the replication of murine sarcoma virus (MSV) in mammalian cells were examined. Glucocorticoids, hydrocortisone (1 to 10 micrograms/ml) and dexamethasone (5 micrograms/ml), enhance transformation induced by the Kirsten strain of MSV (Ki-MSV) in normal rat kidney and human cells 10- to 30-fold. The enhancing effect was much more pronounced in normal human colonic mucosal epithelial-like cells. On the other hand, the hormones estradiol, testosterone, and progesterone had no effect (5 micrograms/ml). Individual foci appeared earlier and were larger in hydrocortisone-treated cells compared with untreated cells. This enhancing effect is further evidenced by the increased virus yield and murine leukemia virus complement-fixing antigen production in the test system. However, such enhancement of hydrocortisone on the Ki-MSV-induced transformation was not observed in mouse embryo cells as previously reported.