SF2523 inhibits human chondrosarcoma cell growth in vitro and in vivo.

Developing novel therapeutic agents against chondrosarcoma is important. SF2523 is a PI3K-Akt-mTOR and bromodomain-containing protein 4 (BRD4) dual inhibitor. Its activity in human chondrosarcoma cells is tested. Our results show that SF2523 potently inhibited survival, proliferation and migration, and induced apoptosis activation in SW1353 cells and primary human chondrosarcoma cells. The dual inhibitor was yet non-cytotoxic to the primary human osteoblasts and OB-6 osteoblastic cells. SF2523 blocked Akt-mTOR activation and downregulated BRD4-regulated genes (Bcl-2 and c-Myc) in chondrosarcoma cells. It was more efficient in killing chondrosarcoma cells than other established PI3K-Akt-mTOR and BRD4 inhibitors, including JQ1, perifosine and OSI-027. In vivo, intraperitoneal injection of SF2523 (30 mg/kg) potently inhibited subcutaneous SW1353 xenograft tumor growth in severe combined immunodeficient mice. Akt-mTOR inhibition as well as Bcl-2 and c-Myc downregulation were detected in SF2523-treated SW1353 tumor tissues. In conclusion, targeting PI3K-Akt-mTOR and BRD4 by SF2523 potently inhibited chondrosarcoma cell growth in vitro and in vivo.