Single-cell transitional dynamics unravel stimulus- and cell type-dependent signaling outputs of distinct p53 regulatory feedback motifs

Despite myriad of systemic analysis, our quantitative understanding of signaling networks and their differential outputs is still limited, especially at the dynamic level. Here we employed a network motif approach to dissect key regulatory units of p53 pathway and determined how their collective activities generated context-specific dynamic responses. By combining single-cell imaging and mathematical modeling of dose-dependent p53 dynamics induced by three chemotherapeutics of distinct mechanism-of-action, including Etoposide, Nutlin-3a and 5-Fluouracil, and in five cancer cell types, we identified novel p53 dynamic modes and their mechanistic origins with new insight on previously unknown drug mediators and phenotypic heterogeneity of cancer cells. Our results established the functional roles of unique feedback motifs of p53 pathway in generating the stimulus- and cell type-specific signaling responses and demonstrated that transitional dynamics activated at intermediate stimulus levels can be exploited as novel quantitative readouts to uncover and elucidate the key building blocks of bio-networks.