Development of methods to validate synthetic lethality induction in vitro and in vivo.

GERMÁN GIL; ANA C. RACCA; SOFÍA CARBAJOSA; GASTÓN SORIA; MARÍA FLORENCIA PANSA; MARÍA CELESTE RODRIGUEZ-BAILI; ANDRÉS CASTELLARO; ALEJANDRA IRIS GARCÍA; LUCIA RODRIGUEZ-BERDINI; AYELEN NIGRA

Congreso; Reunión conjunta de sociedades de biociencias; 2017

One of the current challenges in the development of anticancertherapies lies in the identification of drugs that selectively kill cancercells with minor impact on normal cells. A strategy of selective cytotoxicitythat has yielded promising results is the induction of syntheticlethality (SL). SL induction involves tumor-acquired mutations thatsensitize cells to a given treatment when they are in combination.We are focused in the study of drugs that cause SL in BRCA1/2-deficientcancer cells (Bd-cells). Herein we show the validation of potentialdrugs which have been previously identified as SL-inducersusing a cell-based high-throughput screening platform based onflow cytometry. Three validation methods were developed to assessthe performance of these drugs on a Bd-cell model in comparisonto the wild type cell line (Bw-cells). The first method evaluates theclonogenic potential of Bd-cells and Bw-cells after the treatmentwith the drugs, using an adaptation of the colony formation assay.The second method involves the use of 3D chimeric spheroids constitutedby an equal proportion of Bd-cells and Bw-cells. Both cellpopulations are tagged with different fluorescent proteins and cantherefore be quantified by flow cytometry after the treatments withthe drugs. The third model is a double tumor xenograft approach inNude mice. This model consists in the generation of flanking tumorsin a single mouse, one from Bd-cells and the other from Bw-cells.Mice are then treated with potential SL-inducers or vehicle and theprogression of each tumor-type is assessed in order to expose theSL phenomena in vivo.