Abstract 2686: Methioninase S-phase block of cancer cells imaged in real time by cell-cycle-specific fluorescence reporters

Abstract

Abstract A general feature of cancer cells is their elevated requirement for methionine compared to normal cells, which may be due to excessive methylation reactions in cancer cells since methionine is the global source of cellular methyl groups. When deprived of methionine, cancer cells undergo a cell-cycle arrest in late S-phase. The recombinant bacterial enzyme, methionine β, α-lyase (methioninase or METase) degrades methionine very efficiently and effects an S-phase block selectively in cancer cells. In order to image the kinetics of cell cycle arrest of cancer cells due to deprivation of methionine by METase, cancer cells were engineered to express cell cycle-dependent fluorescent proteins using fluorescent ubiquitination-based cell cycle indicator (FUCCI) whereby cancer cells express Azami-green only in S-phase and Kusabira-orange only in G1. Thus, each cancer could be followed in real time as it becomes blocked in S-phase after METase treatment. FUCCI imaging demonstrated that cancer cells could remain in S-phase for 5 days before starting to die which indicates a new type of cancer cell dormancy. The use of METase treatment and cell-cycle specific fluorescent reporters provide a unique opportunity to image and study the cancer cell cycle and the consequences and advantages of an S-phase block in cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2686. doi:1538-7445.AM2012-2686