Interferon effect on collagen and fibronectin distribution in the extracellular matrix of murine sarcoma virus-transformed cells.

The transformation of murine BALB/c embryonic fibroblasts by murine sarcoma virus, Moloney strain, followed by prolonged treatment with murine interferon, resulted in the appearance of a new cell population (MSV-IF+). These MSV-IF+ cells are characterized by the recovery of a normal phenotype, contact inhibition, and lack of colony formation in agar. This phenotypic change of the MSV-IF+ cells is associated to the neosynthesis of a dense fibrous matrix beyond the cell periphery. Ultrastructural studies using peroxidase-labeled antibodies enabled us to localize the extracellular distribution of fibronectin and collagen in the MSV-IF+ cell line, compared to normal BALB/c and murine sarcoma virus-transformed cells. In parallel, a significant increase of collagen and fibronectin deposit in the intercellular space of interferon-treated murine sarcoma virus-transformed cells was observed.