Abstract 3301: Using a novel single-cell lineage-tracing technique to uncover the mechanisms driving nongenetic cancer relapse

Abstract

Abstract Despite favorable initial response to platinum chemotherapy, the majority of patients with ovarian cancer will develop recurrent disease and succumb to it within 5 years of diagnosis. Initial recurrence is frequently platinum-sensitive and women can respond to multiple lines of platinum-based chemotherapy before eventually developing platinum-refractory disease. The observation that the tumor cells that survive the initial therapy give rise to a chemosensitive progeny is inconsistent with a simple Darwinian model of selection of genetically resistant clones. Tumor dormancy, stochastic cell state shifts and stem cell-like populations are among the mechanisms hypothesized to mediate re-emergence of platinum-sensitive ovarian cancer. However, given the lack of high-throughput methods to simultaneously track cell state and lineage, it is not currently feasible to distinguish the relative contribution of each of these factors. To address this need, we generated a new lentiviral barcode library, termed Watermelon. Unlike existing barcoding libraries that enable the tracking of multiple cancer cells solely at the DNA level, the Watermelon library encodes transcribed barcodes, which allows one to map the lineage to the transcriptional profile of each individual cell. This unique barcoding scheme, which is coupled with a genetic H2B retention system, enables simultaneous tracing of lineage as well as the transcriptional and proliferative states of each cell in the population during drug treatment. We have established and characterized an in vitro platinum-sensitive relapse model and are applying the Watermelon system together with time-lapse imaging to study the mechanisms underlying time-to-relapse variation and cell-fate decisions. By broadening our knowledge of the cellular and molecular pathways that affect noninherited drug resistance, our work will facilitate the future development of novel therapies that delay or even prevent the emergence of platinum-refractory ovarian cancer. Citation Format: Yaara Oren, Aviv Regev, Joan Brugge. Using a novel single-cell lineage-tracing technique to uncover the mechanisms driving nongenetic cancer relapse [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3301.