Metrics other than potency reveal systematic variation in responses to cancer drugs

Mohammad Fallahi-Sichani, Saman Honarnejad, Laura M. Heiser, Joe W. Gray, Peter K. Sorger

Research output: Contribution to journalArticle

162 Scopus citations


Large-scale analysis of cellular response to anticancer drugs typically focuses on variation in potency (half-maximum inhibitory concentration, (IC 50)), assuming that it is the most important difference between effective and ineffective drugs or sensitive and resistant cells. We took a multiparametric approach involving analysis of the slope of the dose-response curve, the area under the curve and the maximum effect (E max). We found that some of these parameters vary systematically with cell line and others with drug class. For cell-cycle inhibitors, E max often but not always correlated with cell proliferation rate. For drugs targeting the Akt/PI3K/mTOR pathway, dose-response curves were unusually shallow. Classical pharmacology has no ready explanation for this phenomenon, but single-cell analysis showed that it correlated with significant and heritable cell-to-cell variability in the extent of target inhibition. We conclude that parameters other than potency should be considered in the comparative analysis of drug response, particularly at clinically relevant concentrations near and above the IC 50.

Original languageEnglish (US)
Pages (from-to)708-714
Number of pages7
JournalNature Chemical Biology
Issue number11
StatePublished - Nov 2013

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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