Antioncogenic effect of adenovirus E1A in human tumor cells.

Stable expression of the adenovirus 5 E1A gene reduced anchorage-independent growth and tumorigenic potential, caused cytoskeletal reorganization, induced flat morphology, and restored contact inhibition in three human tumor cell lines. By these criteria, E1A appears to be functionally indistinguishable from a tumor suppressor gene in this context. The apparent paradox accorded by the observations of the ability of E1A to transform rodent cells in cooperation with other oncogenes suggests that E1A may be the prototype of a class of growth-regulatory proteins having context-specific transforming and antioncogenic activities.