Abstract 4188: Multitargeted tyrosine kinase inhibitor identified as potential therapeutic intervention for liposarcoma using high-throughput profiling
Authors: Kanojia Deepika , Garg Manoj , Martinez Jakki , M.T. Anand , Luty Samuel B , Doan Ngan B , Said Jonathan W , Tyner Jeffrey W , Koeffler H Phillip 
Published: July 2017

Abstract
Liposarcoma is a rare fat cell adult tumor with high risk of recurrence and metastasis, largely underserved by research community and till now limited progress has been made in treatment of this aggressive disease. We used a strategy to identify effective and potential therapeutic kinase inhibitors, irrespective of the activated kinase pathway, using small molecule kinase inhibitor panel. We screened liposarcoma cell lines of different histotypes to a panel of small molecule kinase inhibitors and analyzed using cell proliferation assay. In vitro cell proliferation assay, colony formation, cell cycle analysis, apoptosis assay and western blotting analysis were performed to investigate the effect and mechanism of inhibitor treatment on liposarcoma. Liposarcoma xenograft model system was also employed to investigate anti-tumor in vivo effects of inhibitor treatment. We observed that cell lines demonstrated diverse in vitro drug sensitivity patterns to various kinase inhibitors. Most of the cell lines showed very high sensitivity towards inhibitors targeting proteasome, protein kinase C, Hsp90, PI3K, mTOR and CDKs. Among the receptor tyrosine kinase inhibitors; Ponatinib, Dasatinib, and Sunitinib are the top most sensitive drugs affecting liposarcoma cells lines’ viability irrespective of subtypes and all these are already approved by the U.S. Food and Drug Administration to treat various cancers. We studied multi-targeted tyrosine kinase inhibitor ponatinib as an effective potential drug molecule in liposarcoma. We demonstrated that ponatinib treatment in liposarcoma cell lines reduced the levels of phosphorylated KIT compared to total KIT protein levels in dose dependent manner. Further, western blotting experiments revealed effect of ponatinib treatment on KIT downstream signalling by inhibiting the phosphorylation of AKT, ERK1/2, STAT3, mTOR, P70S6K and RB without affecting their total protein levels. Significant reduction in cell number and colonies with ponatinib treatment implicates anti-neoplastic effects in liposarcoma. Ponatinib treatment causes cell cycle arrest at G0/G1 phase by regulating CDK4 and cyclinD1 proteins levels. It also induces apoptosis of treated cells by downregulating AKT and ERK signaling pathway leading to dephosphorylation of BAD. Similar growth inhibiting effect of ponatinib was demonstrated in in vivo liposarcoma xenograft model. In vitro drug sensitivity profiling of liposarcoma highlighted Ponatinib, an oral FDA approved drug, as potential therapeutic drug candidate for treatment and management of this deadly tumor.
Citation Format: Deepika Kanojia, Manoj Garg, Jakki Martinez, Anand M.T., Samuel B Luty, Ngan B Doan, Jonathan W Said, Jeffrey W Tyner, H Phillip Koeffler. Multitargeted tyrosine kinase inhibitor identified as potential therapeutic intervention for liposarcoma using high-throughput profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4188. doi:10.1158/1538-7445.AM2017-4188