Targeting Notch3 signaling in lung cancer
Dysregulation of the Notch signaling pathway plays an important role in lung cancer pathobiology. The Notch3 receptor is overexpressed in ∼40% of resected non-small cell lung cancers, and its suppression results in loss of the malignant phenotype both in vitro and in vivo. In this dissertation, I have identified novel ligand binding regions in the Notch3 receptor using a high throughput system and a Notch3 peptide library that spans the extrcellular domain. This knowledge allowed me to generated Fc-fusion proteins and neutralizing monoclonal antibodies to target these regions in the Notch3 receptor thereby interfering with signaling by blocking the interaction of the receptor with it’s ligands. In addition, I explored the roles of Jagged1, a Notch ligand, in lung cancer. I demonstrate that Jagged1 has the paradoxical roles of increasing cell growth and suppressing migration. Interestingly, this appears to be through a noncanonical, CSL-independent mechanism. The findings of these studies not only give novel insights into Notch3 signaling but also establish a foundation on which targeted therapies can be developed.