Abstract 2330: Activation of cancer stem cells by oncogenic K-Ras requires activated Wnt/β-catenin signaling

Abstract

Abstract Adenomatous polyposis coli (APC) loss-of-function mutations and K-Ras gain-of-function mutations are common abnormalities that occur during the initiation and intermediate adenoma stages of colorectal tumorigenesis, respectively. However, little is known about the role of these mutations in the regulation of cancer stem cells (CSCs) associated with colorectal cancer (CRC) tumorigenesis. We analyzed tissue from CRC patients (n = 49) and observed an association between K-Ras mutations and CSC activation during colorectal tumorigenesis. The oncogenic K-Ras mutations enhanced stemness of CRC cells carrying an APC mutation, as shown by comparisons of sphere formation, transforming potential, and differentiation in vitro and tumor-forming capacity in vivo between isogenic APC mutated CRC cells harboring either wild-type or mutant K-Ras. Moreover, the activation of CSC by K-Ras mutations in CRC required an additional APC mutation, as revealed by the induction of CD44, CD133, and CD166 in intestinal tumor tissues of APCMin/+/K-RasLA2 double-mutant mice, but not in K-RasLA2 mice. Overall, the progression and metastasis of CRC induced by K-Ras mutation occurs by initial activation of CSC by APC loss and further activation of Wnt/β-catenin signaling and subsequent activation of Ras-ERK signaling. Citation Format: Byoung-San Moon, Kug Hwa Lee, Kyounghwa Koo, Kang-Yell Choi. Activation of cancer stem cells by oncogenic K-Ras requires activated Wnt/β-catenin signaling. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2330. doi:10.1158/1538-7445.AM2015-2330