ABSTRACT
Abelson murine leukemia virus is an acutely transforming replication-defective virus which encodes a transforming protein with tyrosine-specific protein kinase activity. A variety of benzopyranone and benzothiopyranone derivatives have been identified which selectively inhibit the v-abl tyrosine protein kinase with 50% inhibitory concentrations ranging from 1 to 30 microM. The most active derivative inhibited v-abl with a Ki value of 0.9 microM. Active derivatives showed selectivity for the v-abl tyrosine protein kinase relative to the epidermal growth factor receptor tyrosine protein kinase (50% inhibitory concentration greater than 100 microM). Protein kinase C and protein kinase A, two members of the serine/threonine protein kinase family, were not inhibited by benzopyranones or benzothiopyranones (50% inhibitory concentration greater than 100 microM). Kinetically, a representative derivative (compound 2) showed competitivity with respect to ATP and noncompetitive behavior with respect to the exogenous peptide substrate. Autophosphorylation of p120v-abl and recombinant p70v-abl tyrosine protein kinases were also inhibited by benzopyranones and benzothiopyranones in vitro. When tested in Abelson murine leukemia virus-transformed BALB/c cell, active benzopyranone and benzothiopyranone derivatives inhibited tyrosine phosphorylation of cellular proteins by the v-abl tyrosine protein kinase.
