Abstract 4257: Gene expression and genomic drift comparative analysis between patient-derived conditionally reprogrammed cells and original tumors

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Abstract First two authors contributed equally Last two authors contributed equally Recent studies have shown that ex vivo propagation of normal tissues or patient-derived tumor cells in presence of irradiated fibroblast feeder cells and ROCK inhibitor can rapidly establish conditionally reprogramed cells (CRCs). In case of normal tissues, the induction of CRCs was reversible when the ROCK inhibitor and the feeder cells were removed, resulting in CRCs differentiating to its tissue origin (Liu et al.2012). Previous publications suggested that the establishment of such cell models provides new strategies to understand acquired resistance during treatment (Crystal et al 2015) and to predict treatment response (Liu et al. 2014). However, gene expression modulations and genomic drifting during the establishment of CRC propagation have not been thoroughly studied. The primary goal of this study is to molecularly characterize alterations between the original tumor tissues and the derived models growing with or without ROCK inhibitor. Understanding in-depth molecular fluctuations in this patient-derived ex vivo system will facilitate its appropriate use for tumor biology experimentation. Herein, tumors from prostate cancer and breast cancer patients were surgical removed and cryopreserved at the clinical site then processed and cultured as previously described (Liu et al. 2012). Gene expression profiling and next-generation sequencing were carried out on the original tumor tissues and cellular models passaged during the CRC propagation in the presence or absence of ROCK inhibitor. Gene expression analysis of the prostate cancer cells and the breast cancer cells were carried out using a 93-gene prostate cancer-focused Fluidigm panel and a 800 gene NanoString breast cancer-focused panel, respectively. Cancer hotspot mutations were analyzed using the Ion Torrent Cancer Hotspot v2 NGS assay. Through aforementioned genomic and transcriptomic interrogations, we demonstrated the extent of indication-relevant gene expression modulation during establishment and propagation of these cells. We also characterize cancer hotspot mutations in the primary tumor cells and the stability of those mutations during ex vivo propagation. These results should begin to inform the appropriate use of the CRC model for tumor biology experimentation. Citation Format: Jessica Li, Bonnie Liu, Rin Nakamura, Heidi Savage, Shoji Ikeda, Timothy Wilson, Teiko Sumiyoshi, Garret Hampton, Lukas Amler, Mark Lackner, Shih-Min A. Huang, Walter C. Darbonne. Gene expression and genomic drift comparative analysis between patient-derived conditionally reprogrammed cells and original tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4257.