Abstract 275: A possible relationship between gene mutation profiles and activity of E7386 in in vitro models of colorectal cancer organoids
Authors: Imai Toshio , Naruse Mie , Ochiai Masako , Ozawa Yoichi , Owa Takashi , Ochiai Atsushi 
Published: August 2019

A novel beta-catenin/CBP binding modulator E7386 is expected to affect colorectal carcinoma (CRC) cells particularly those with aberrant activation of Wnt/beta-catenin signaling pathway. The Wnt signaling pathway is recently reported to play important roles for activation of not only CRC cells but also cancer-associated fibroblasts (CAFs). Here, we established an in vitro model of CRC-derived organoids as well as a co-culture method of the CRC organoids with CAFs, and effects of E7386 on the growth of the organoids were examined. Fragments of CRC tissues from a total of 45 patients who underwent surgery were obtained, dissociated into single cells, which were seeded on polymerized Matrigel (Corning), and cultured with serum-free media containing EGF and Noggin optimized for organoids using 12-well plates. Fourteen CRC organoids from 45 cases were successfully established. For 2D culture of CAFs from CRC tissues of each patient, RPMI medium containing 10% FBS was used. A co-culture method of the CRC organoids with CAFs was applied using a double chamber system with transwell inserts in 24-well plates. Cell viabilities of the organoids and CAFs were measured using CellTiter-Glo Luminescent Cell Viability Assay reagent (Promega). Gene aberrations in original CRC tissues were analyzed using NCC Oncopanel, and gene expression profiles in established CRC organoids and CAFs were analyzed using SurePrint G3 Human GE microarray (Agilent). [Effects of CAFs on cell viabilities and gene expressions of organoids] Cell viabilities of organoids and CAFs appeared to increase at 72 hours after beginning of the culture by 2 to 8 and 1 to 2-fold, respectively. When organoids were co-cultured with CAFs, cell viabilities of organoids were increased and epithelial-mesenchymal transition-related gene expressions were dramatically changed in several cases, but not in all cases. The organoids co-cultured with CAFs appeared to be more sensitive to E7386 as compared to those cultured alone. [Possible relationship between gene mutations in CRCs and activity of E7386 in CRC organoids] Cell viabilities of organoids without APC mutations (n=1) and organoids with APC and TP53 mutations alone (n=2) were less than those of organoids with other oncogene mutations, e.g., KRAS or PIK3CA (n=4). Efficacy of E7386 on the cell viabilities of organoids with APC and TP53 mutations alone was found at lower concentrations at 30-100 nM, as compared to those of organoids without APC mutations. From the results, CRC organoids were established from 14 patients, and activity of E7386 appeared to be related to gene mutation profiles in the established CRC organoids.

Citation Format: Toshio Imai, Mie Naruse, Masako Ochiai, Yoichi Ozawa, Takashi Owa, Atsushi Ochiai. A possible relationship between gene mutation profiles and activity of E7386 in in vitro models of colorectal cancer organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 275.