E2F1 and ovarian cancer: To design the input modules for the sensing circuit, we used two SPECS, S(E2F1)P and S(cMyc)P29, which were previously demonstrated to be specific to the OVCAR8 ovarian cancer cell line29, to transcribe the endoribonuclease Cys4 gene (Input 1) and a novel miRNA-based self-inhibitory gene module (Input 2), respectively (Fig. 2A).