Population ecology of heterotypic tumour cell cultures

Objectives: Here, we propose a population ecology perspective to describe dynamic interplay between human leukaemia and cervical cancer cells growing together in the same environment. Materials and methods: MOLT-3 (human T-lym- phoblastic leukaemia) and HeLa (human cervical adenocarcinoma) cells were grown together or alone. Living cells were measured using flow cytometry, by counting propidium iodide-negative cells either CD5+ (MOLT-3) or CD55+ (HeLa). We developed a mathematical model to take into account possible interactions between cells and among cells and their environmental niches. Model equations were then fitted to growth data. Results: Ecological interactions that require direct cell contact and indirect mechanisms acting on cell niches, successfully modelled cell population growth. Predicted heterotypic adhesion between the two different cell types was demonstrated experimentally. Conclusions: Theoretical ecology can be assayed using human cells and, most importantly, it can provide a conceptual framework to describe and understand evolution of mixed tumour cell populations.