Efficacy of phosphatidylinositol-3 kinase inhibitors in a primary mouse model of undifferentiated pleomorphic sarcoma

Abstract

Recent advances in sarcoma genomics have identified novel mutations in the PI3K pathway in human sarcomas. Here, we use a mouse model of primary soft-tissue sarcoma for preclinical testing of doxorubicin and inhibitors of the PI3K pathway: BKM120 (PI3K inhibitor) and BEZ235 (a dual PI3K/mTOR inhibitor). Doxorubicin-treated tumors (n=15) showed a partial response rate of 6.6, just as the majority of human sarcomas do not respond to doxorubicin. Treatment with BKM120 elicited a partial response in 50 of tumors (n=10), which was also seen in combination with doxorubicin (n=10). Additionally, BKM120 treatment produced a robust delay in tumor growth kinetics. BEZ235-treated tumors (n=9) showed a complete response rate of 11.1. Combining BEZ235 with doxorubicin (n=10) increased the complete response rate to 50 (P=0.035). These studies demonstrate that PI3K pathway inhibition is a viable and attractive target for soft-tissue sarcomas. Copyright 2012 Suzy Kim et al.