Efficacy of Phosphatidylinositol-3 Kinase Inhibitors in a Primary Mouse Model of Undifferentiated Pleomorphic Sarcoma

Abstract EN

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.