Conditionally Reprogrammed Cells (Crcs): A New Model For Cancer Research And Personalized Medicine

Background: Current cancer cell lines often fail to reflect the genotypes and phenotypes of the tumors from which they were derived due to the accumulation of genetic and epigenetic alterations during passage in vitro. This obviously limits the ability to use such cell lines for predicting responses to drug-, radiation-, or immuno-therapies. Until recently, it remained a challenge to rapidly and efficiently generate cell cultures from individual patients in a time-limited manner that allowed for choosing appropriate therapies. Last year we described the use feeder cells and a ROCK inhibitor to induce the conditional reprogramming of adult epithelial cells into a basal or stem-like (AJP, 2012, 2013; NEJM, 2012, PNAS 2012). Cultures generated from normal tissue, referred to as conditionally reprogrammed cells (CRCs), do not express high levels of proteins characteristic of iPSCs or ESCs such as Sox2, Oct4, Nanog, or Klf4. More important, the induction of CRCs is reversible, and the removal of feeders and ROCK inhibitor allows cells to differentiate normally to tissue origin. The CRC technology can generate 2×10 6 cells in 5 to 6 days from needle biopsies, and can generate cultures from cryopreserved tissue and from fewer than four viable cells. Primary goal: The clinical utility of CRCs for patient care needs to be established. We therefore initiated studies to examine whether CRCs established from tumors would reflect the biology and genotype of the original tumor and whether the tumor CRCs could be used to predict clinical responses. Procedures: We used CRC methods to generate matched cultures from both tumor cells and adjacent normal cells from cancer patients and relevant mouse models. We characterized these CRC lines for their growth properties, induction of tumors in immunodeficient mice, karyotype, differentiation, and transcriptome profile. We also compared the sensitivity of the matched CRCs to commonly used chemotherapy drugs. Results: The CRC technique efficiently established cell cultures from human and rodent tumors. For example, we established matched normal and tumor CRCs for a patient with a squamous carcinoma of the tongue. The tumor CRC from this patient exhibited a highly abnormal karyotype and harbored a mutation of the p53 gene. The matched normal CRC exhibited a normal karyotype and wild p53. The tumor CRCs, but not the normal CRCs, efficiently induced squamous cell carcinomas when injected subcutaneously into nude mice. Similarly, we generated 4 cultures from pancreatic cancers, 3 of which exhibited mutations in the Ras gene. We were also able to utilize the CRC method to define an effective therapy for patient with an aggressive lung papillomatosis. Finally, our studies indicate that we are able to generate micro-heterogenous tumor CRCs from a small biopsy. Conclusion: CRCs show promise for evaluating tumor responses to selected therapies and for defining the functional heterogeneity of their respective primary tumors. Citation Format: Xuefeng Liu, Ewa Krawczyk, Nancy Palechor-Ceron, Weisheng Wang, Hang Yuan, Aleksandra Dakic, Vera Simic, Bhaskar Kullakury, Priscilla Furth, Richard Schlegel. Conditionally reprogrammed cells (CRCs): A new model for cancer research and personalized medicine. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2972. doi:10.1158/1538-7445.AM2014-2972