Abstract 3900: Pten deletion in SOX9+ cells leads to tumor initiating cell expansion and tumor development in mouse liver

Abstract Liver cancer is one of the most aggressive malignancies with a five-year survival rate less than 10%. There is thus an urgent unmet need to understand the process of liver tumorigenesis in order to develop early diagnosis and effective therapeutic treatments. Clinical studies have suggested that tumor initiating cell (TIC) activation is observed in over 70% of liver cancer samples and is closely linked with poor survival outcome after treatment. Consistent with these observations, our previous studies utilizing a Pten (loxp/loxp); Albumin-Cre+ mouse liver cancer model also confirmed the expansion of TICs during liver tumorigenesis. However, how TICs are activated and what mechanisms contribute to liver tumor development remains unclear. Here, we studied the role of tumor suppressor PTEN in TICs using the Pten (loxp/loxp); SOX9-CreER+ mouse model. Lineage tracing results indicated that in the liver SOX9+ cells possess the progenitor cell characteristics and give rise to bile duct cells and peri-portal hepatocytes later on. Pten deletion in SOX9+ cells at 4 weeks of age leads to expansion of both CK+ duct cells and HNF4+ hepatocytes in the peri-portal areas. Interestingly, we also observed tumor development at 12 months old mutant mice and close examinations revealed that the tumors are heterogeneous, indicating the contribution of TICs during this process. Together, our study suggested that the PTEN signaling is critical for TICs regulation and that TICs activation plays a key role in liver tumorigenesis. Citation Format: Ni Zeng, Janel Kopp, Lina He, Maike Sander, Bangyan Stiles. Pten deletion in SOX9+ cells leads to tumor initiating cell expansion and tumor development in mouse liver. [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 3900. doi:10.1158/1538-7445.AM2014-3900