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Induction of apoptosis increases sensitivity to detect cancer mutations in plasma

2020; Elsevier BV; Volume: 127; Linguagem: Inglês

10.1016/j.ejca.2019.12.023

1879-0852

Joana Marques, Susana Junqueira-Neto, Jorge Pinheiro, José Carlos Machado, José Luís Costa,

CRISPR and Genetic Engineering

BackgroundThe study of cell-free DNA (cfDNA), namely the fraction derived from tumors (ctDNA), is a clinically relevant noninvasive biomarker for cancer management. However, the intrinsic low abundance of ctDNA in plasma limits its implementation in the clinic.Aim of the studyIn this study, the objective was to demonstrate that induction of apoptosis—the major source of ctDNA—increases ctDNA concentration, thereby increasing the sensitivity to detect clinically relevant mutations in plasma.MethodsIn vitro models were used to test the effect of docetaxel on the release levels of DNA from lung cancer cells. In vivo, Rag2−/− IL2rg−/− immunodeficient C57BL/6 xenografted mice were treated with docetaxel for 24 h or 48 h. Tumor tissue and blood were collected to evaluate the levels of apoptosis DNA release levels, respectively.ResultsWe observed increased levels of apoptosis in H1975 cells and a consequent increase in cfDNA released into the culture medium after docetaxel treatment. In vivo, the results show increased cfDNA concentration in plasma of xenografted mice after apoptosis stimulation. Importantly, treatment increased the sensitivity of detection of relevant cancer mutations, namely 24 h after treatment.ConclusionThis study provides new insights regarding the importance of timing for blood collection. In our experimental model, we demonstrate that blood collection should be performed 24 h after treatment (apoptosis induction), for optimal ctDNA analysis. Translating these results into the clinical setting is likely to increase sensitivity to detect tumor-derived mutations in plasma, might help guide the therapeutic decision, and optimize current liquid biopsy procedures for situations where tissue analysis is not possible.