The induction of smooth muscle α actin in a transformed rat cell line suppresses malignant properties in vitro and in vivo

A normal rat fibroblast 3Y1 cell line expresses smooth muscle α actin and the expression of α actin is suppressed in the transformant (SR-3Y1-2) induced by a Raus sarcoma virus. Gene transfer with smooth muscle α actin into the SR-3Y1-2 cell line reduced growth and invasiveness in vitro, as well as tumor growth and experimental lung metastasis depending on the expression of the α actin. These results indicated that smooth muscle α actin is involved in the regulation of cell growth as well as cell motility and thus leads to the suppression of malignant phenotypes in transformed cells.