RT Journal Article
SR Electronic
T1 High complexity cellular barcoding and clonal tracing reveals stochastic and deterministic parameters of radiation resistance
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.10.13.337519
DO 10.1101/2020.10.13.337519
A1 Anne Wursthorn
A1 Christian Schwager
A1 Ina Kurth
A1 Claudia Peitzsch
A1 Christel Herold-Mende
A1 Jürgen Debus
A1 Amir Abdollahi
A1 Ali Nowrouzi
YR 2020
UL http://biorxiv.org/content/early/2020/10/19/2020.10.13.337519.abstract
AB The impact of functional heterogeneity in response to radiation therapy is poorly understood to the present. It remains elusive whether clonal selection of tumor cells in response to ionizing radiation (IR) is a deterministic or stochastic process. We applied high-resolution lentiviral cellular barcoding for quantitative clonal tracking and deconvolution of clonal dynamics in response to IR. Clonal tracking of over 400.000 HNSCC patient-derived tumor cells and the analyses of over 1500 million sequencing reads in clonogenic survival assays reveals that fractionated IR induced a strong selective pressure for clonal reduction. This significantly exceeded uniform clonal survival probabilities indicative for a strong clone-to clone difference within tumor cell lines. IR induced clonal reduction affected the majority of tumor cells ranging between 96-75% and correlated to the degree of radiation sensitivity. Survival and clonogenicity is characterized by an intensive clonal distortion and dominance of individual tumor cells. Survival to IR is driven by a deterministic clonal selection of a smaller population which commonly survives radiation, while increased clonogenic capacity is a result of clonal competition of cells which have been selected stochastically. A 2-fold increase in radiation resistance results in a 4-fold (p<0.05) higher deterministic clonal selection showing that the ratio of these parameters is amenable to radiation sensitivity which correlates to prognostic biomarkers of HNSCC. Evidence for the existence of a rare subpopulation with an intrinsically radiation resistant phenotype commonly surviving IR was found at a frequency of 0.6-3.3% (p<0.001, FDR 3%). With cellular barcoding we introduce a novel functional heterogeneity associated qualitative readout for tracking dynamics of clonogenic survival in response to radiation. This enables the quantification of intrinsically radiation resistant tumor cells from patient samples and reveals the contribution of stochastic and deterministic clonal selection processes in response to IR.Competing Interest StatementThe authors have declared no competing interest.