Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery: Bridging Experiments and Computations - September 10-14, 2014, Istanbul, Turkey

Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery Poster Session I

30-POS Board 30 Transcriptomic Profiling to Reveal Therapeutic Targets and Cellular Mechanisms of Drug Resistance in Liver Cancer Tulin Ersahin 1 , Deniz Cansen Yildirim 1 , Aybar C. Acar 2 , Rengul Cetin-Atalay 1 . 1 Bilkent University, Ankara, Turkey, 2 Middle East Technical University, Ankara, Turkey. Liver cancer is one of the leading causes of cancer-related deaths worldwide with limited therapeutic options for advanced Hepatocellular carcinoma (HCC). Yet, the only FDA-approved therapeutic agent, Sorafenib, which targets RAF/MEK/ERK pathway, fails to prevent tumor recurrence due to persistent signaling through alternative PI3K/AKT/mTOR pathway. In this study, we show that targeting of PI3K/AKT/mTOR signaling by small molecule inhibitors is cytotoxic in HCC cells, the underlying transcriptomic response is dependent on Akt activation status, and combination of inhibitors of PI3K or AKT and Sorafenib leads to synergistic growth inhibition and enhanced cell death. Cytotoxic activities of nine small molecule inhibitors of PI3K/AKT/mTOR pathway were shown by SRB and RT-CES assays in HCC cell lines having normal or hyper-active AKT protein. Apoptotic cell death, and suppression of cell cycle progression and migration were shown by flow cytometry, wound healing, immunofluorescence and western blots experiments. When used in combination with Sorafenib, two most potent inhibitors, PI3Ki-alpha and Akti-2, showed synergistic actions on HCC cells in vitro and in vivo mice xenografts. Computational analysis of microarray and RNA-seq data acquired in the presence of these agents alone or in combination with Sorafenib identified specific gene sets. KEGG pathways were used to visualize drug-mediated regulation of cellular signaling in molecular level in Cytoscape. Our transcriptomic analysis identified direct enzymatic targets and key downstream effector proteins. Comparison of the transcriptomic profiles of Sorafenib, PI3Ki-alpha and Akti-2 as single and combined agents revealed proteins that are responsible for enhanced cytotoxic activity and suggested new targets.

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