Data from: Resource competition promotes tumour expansion in experimentally evolved cancer

Tumour progression involves a series of phenotypic changes to cancer
cells, each of which presents therapeutic targets. Here, using techniques
adapted from microbial experimental evolution, we investigate the
evolution of tumour spreading - a precursor for metastasis and tissue
invasion - in environments with varied resource supply. Evolutionary
theory predicts that competition for resources within a population will
select for individuals to move away from a natal site (i.e. disperse),
facilitating the colonisation of unexploited resources and decreasing
competition between kin. After approximately 100 generations in
environments with low resource supply, we find that MCF7 breast cancer
spheroids (small in vitro tumours) show increased spreading. Conversely,
spreading slows compared to the ancestor where resource supply is high.
Common garden experiments confirm that the evolutionary responses differ
between selection lines; with lines evolved under low resource supply
showing a plastic spreading phenotype. These differences in spreading
behaviour between selection lines are heritable (stable across multiple
generations), and show that the divergently evolved lines differ in their
response to resource supply. It is possible that prolonged resource
limitation itself causes a stable switch toward dispersal-like behaviour
and an increased sensitivity to resource availability without the need for
genetic change. Different clinical strategies may be needed depending on
whether tumour progression is due to stable or plastic effects. This study
highlights the effectiveness of experimental evolution approaches in
cancer cell populations and demonstrates how simple model systems might
enable us to observe and measure key selective drivers of clinically
important traits.