Parallel mouse studies were performed to have, in addition to AML cells, access to liver tissue, a major target of statins.
Serum cholesterol levels were lowered by simvastatin in all patients, however, only limited changes in the messenger RNA expression of cholesterol metabolism genes were seen in patient and mouse MNCs compared to murine liver cells. Still, two out of seven patients displayed an increased in vitro chemosensitivity of their AML cells upon simvastatin treatment.
Gene set enrichment analysis on microarray data of AML patient cells and Western blot analysis for the isoprenylated proteins DnaJ and Rap1 on murine and AML patient MNCs demonstrated that in vivo simvastatin treatment resulted in inhibition of geranylgeranylation in murine MNCs and in a subset of patient AML MNCs. In summary, our data demonstrate that simvastatin treatment results in chemosensitization and inhibition of geranylgeranylation in AML cells of a subset of patients.