Ferrous iron–activatable drug conjugate achieves potent MAPK blockade in <i>KRAS</i> -driven tumors
Honglin Jiang, Ryan K. Muir, Ryan L. Gonciarz, Adam B. Olshen, Iwei Yeh, Byron Hann, Ning Zhao, Yung-Hua Wang, Spencer C. Behr, James E. Korkola, Michael J. Evans, Eric A. Collisson, Adam R. Renslo
Abstract
KRAS mutations drive a quarter of cancer mortality, and most are undruggable. Several inhibitors of the MAPK pathway are FDA approved but poorly tolerated at the doses needed to adequately extinguish RAS/RAF/MAPK signaling in the tumor cell. We found that oncogenic KRAS signaling induced ferrous iron (Fe2+) accumulation early in and throughout mutant KRAS-mediated transformation. We converted an FDA-approved MEK inhibitor into a ferrous iron-activatable drug conjugate (FeADC) and achieved potent MAPK blockade in tumor cells while sparing normal tissues. This innovation allowed sustainable, effective treatment of tumor-bearing animals, with tumor-selective drug activation, producing superior systemic tolerability. Ferrous iron accumulation is an exploitable feature of KRAS transformation, and FeADCs hold promise for improving the treatment of KRAS-driven solid tumors.