Abstract 5319: Cancer reprogramming.

Abstract

Abstract Background: The 2012 Nobel Prize success (Gurdon and Yamanaka) gives boost to medical science. While the nuclear transplantation but also the gene transfer of defined factors can elicit cellular reprogramming efficiently in terminally differentiated somatic cells, we have been studied the effects of coding genes (oncogenes [OG], tumor suppressor genes [TSG], and ES-like genes) and non-coding ones (microRNA) on the gastrointestinal cancer cells (reviewed in JAMA, 2001; Cancer Sci, 2008). Compared with known tumor-related genes [OG/TSG], the retroviral-mediated gene transfer of induced pluripotent stem cells (iPSCs) factors, such as Oct4, Sox2, Klf4 and c-Myc resulted in radical modifications of cell lineages, more sensitization to anti-cancer reagents, and significant suppression of tumorigenesis in immunodeficient NOD/SCID mice (PNAS, 2010; BBRC, 2010; IJO, 2012). Given that the viral vectors have potential risks for genome insertion causing carcinogenesis, which would offend clinical application, our extensive screening of ES cell-specific microRNAs allowed the identification of a set of microRNAs (microRNA302 s, 200c and 369 s), which could execute full reprogramming from differentiated cells to iPSCs (Cell Stem Cell, 2011; Cancer Sci, 2011). Here we studied the effect of those microRNAs on gastrointestinal cancer cells in vitro and in vivo. Methods: To inactivate cancer cells, we screened a small set of microRNAs by in vitro experiments, including cell growth, invasion, sphere formation, differentiation assay (three germs) and immunocytochemistry; and in vivo ones, such as chemo-sensitivity, teratoma assay and tumorigenesis. For in vivo assay, synthesized microRNAs were administered intravenously as conjugated forms with carbonate apatite, a novel microRNA delivery technology. The fluorescent labeled microRNAs monitored the efficiency in cancer tissue uptakes as well as the toxicity in normal tissues. Result: 1) Single microRNA302s were able to reprogram colorectal cancer HT29 cells in vitro, as shown by microscopic analysis and qRT-PCR: three germ line differentiation, reduced proliferation and suppressed invasion. 2) Cell fate analysis in vitro demonstrated that ∼60% of HT29 cells reprogrammed, while remaining cells were subjected to apoptosis induction. The reprogrammed cells were sensitized to chemotherapy (fluorouracil). 3) In vivo study showed the microRNA302s effect on tumors, but not on normal tissues, to suppress tumorigenesis significantly in immunodeficient NOD/SCID mice. Conclusion: In vitro and in vivo assay demonstrated clearly that cancer-reprogramming therapy using synthesized microRNAs could modify the cancer cell malignancy, and that the combination with efficient DDS's would facilitate the discovery of innovative cancer therapy. We study further the mechanism microRNA-mediated cancer reprogramming for the drug optimization. Citation Format: Hisataka Ogawa, Hirofumi Yamamoto, Masamitsu Konno, Shin Kure, Susumu Miyazaki, Shinpei Nishikawa, Shinichiro Hasegawa, Katsuya Ohta, Yoshihiro Kano, Takahito Fukusumi, Atsushi Hamabe, Takeshi Yamamoto, Satoshi Obika, Taroh Satoh, Hidetoshi Eguchi, Hiroaki Nagano, Hidenori Inohara, Yuichirou Doki, Masaki Mori, Hideshi Ishii. Cancer reprogramming. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5319. doi:10.1158/1538-7445.AM2013-5319