Inhibition of tyrosine kinase and epidermal growth factor receptor internalization by lavendustin A methyl ester in cultured A431 cells.

Lavendustin A is a novel microbial secondary metabolite that strongly inhibits tyrosine kinase in vitro. But, since it was found that it did not inhibit tyrosine kinase in situ, possibly because of its poor penetration into the cells, the authors therefore synthesized a methyl ester derivative of lavendustin A. Lavendustin A methyl ester inhibited autophosphorylation and internalization of epidermal growth factor receptor in cultured A431 cells. It also inhibited phosphatidylinositol kinase in vitro and phosphatidylinositol turnover in situ.