Fluorescence-based co-culture of normal and cancerous cells as an indicator of therapeutic effects in cancer.

Comprehensive evaluation of the effects of cancer therapies in vitro is difficult because of the need to distinguish the main effects from the side effects within the data. This problem cannot be overcome by methods involving monoculture, because the effects of anti-cancer drugs in a monoculture can only be measured on either normal or cancerous cells in isolation. In order to promote therapeutic development, therefore, we need a novel drug evaluation method which can simultaneously determine both therapeutic activity and toxicity under a co-culture of normal and cancerous cells. Co-culture creates a more biomimetic condition in comparison to monoculture. The novel method proposed in this study uses an easy experiment for estimating the effects of treatments with various kinds of drugs as a solution to the abovementioned problems. We have previously established two cell lines: a rat gastric mucosal cell line (RGM) and its corresponding cancerous mutant cell line (RGK). In this study, we have developed a new evaluation procedure using a co-culture of green fluorescent protein-expressing RGM cells (RGM-GFP) and kusabira orange-expressing RGK cells (RGK-KO). These cell lines emit green and red fluorescence, respectively. We demonstrated the capability of the method in evaluations of the cancer-selective effects of anti-cancer drugs and X-ray treatment. These results clearly distinguished the cancer-selective toxicity of the applied therapies.