Abstract 5473: Human cancer cells acquire chemoresistance to gemcitabine mainly through loss-of-function mutations in the DCK gene

Abstract

Abstract Gemcitabine (GEM) has shown clinical activity in several solid tumors such as pancreatic and biliary tract cancers, urinary cancer, and non-small cell lung cancers, but a substantial number of patients acquire GEM chemoresistance. GEM functions after phosphorylation by deoxycytidine kinase (DCK) and its inactivation is one of the important mechanisms for acquisition of gemcitabine resistance. We established eight GEM resistant cell lines including four pancreatic, two biliary tract, and two gastrointestinal cancers and investigated mechanisms for acquisition of GEM resistances; six GEM resistant cell lines harbored complete inactivating mutations of DCK by protein-truncating mutation or complete or partial loss of the gene, and one gastric cancer cell line harbored a missense mutation that inactivate DCK activity. One pancreatic cancer cell line lost GEM sensitivity by unknown mechanism. Our present results strongly suggest that genetic alteration of DCK can be the major cause of acquisition of GEM resistance. Further studies analyzing primary tumors will give us (1) the fully understanding of acquisition of GEM resistance, and (2) desirable clues to overcome the acquisition of GEM resistance. Citation Format: Akira Horii, Yuriko Saiki, Tomohiro Nakano, Chiharu Kudo, Makoto Sunamura. Human cancer cells acquire chemoresistance to gemcitabine mainly through loss-of-function mutations in the DCK gene. [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 5473. doi:10.1158/1538-7445.AM2015-5473