Understanding the Consequences of Oncogenic FGFR Mutations on Drug Resistance, Signaling, and Tumorigenic Potential [electronic resource].

9781392328682

Ann Arbor : ProQuest Dissertations & Theses, 2019.

1 online resource (163 p.)

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Fibroblast growth factor receptor 1 (FGFR1) has been implicated in numerous cancer types including squamous cell lung cancer, a subset of non-small cell lung cancer (NSCLC) with a dismal 5-year survival rate. Small molecule inhibitors targeting FGFR 1 are currently in clinical trials, with AZD454 7 being one of the furthest advanced; however, the development of drug resistance is a major challenge for targeted therapies. A prevalent mechanism of drug resistance in kinases occurs through mutation of the gatekeeper residue, V561 M in FGFR 1; however, mechanisms underlying V561 M resistance to AZD4547 are not fully understood. I have characterized the kinetic parameters of V561 M FGFR1 as compared to WT FGFR1 including rates of autophosphorylation and substrate phosphorylation, ATP binding affinity, and binding affinity of two small molecules in clinical trials, E3810 and AZD4547. After finding that V561 M FGFR 1 maintains nM binding affinity for AZD4547, I tested the sensitivity of cells expressing WT or V561 M FGFR1 to AZD4547 and found drastic drug resistance suggesting an alternate mechanism of resistance at play in addition to reduced binding affinity. To investigate the mechanism of resistance, I characterized the cellular consequences of the V561 M gatekeeper mutation, and demonstrated that the dramatic AZD457 resistance observed in cells expressing V561 M is driven by increased STAT3 activation downstream of V561M FGFR1. I also showed that the V561M mutation biases cells towards a more mesenchymal phenotype, as well as increasing tumorigenic potential, manifested through increased levels of proliferation, migration, invasion and anchorage-independent growth. I confirmed marker expression and pathway activation using CyTOF, a novel single cell analysis tool. Using shRNA knockdown, I demonstrated that loss of STAT3 restores sensitivity of cancer cells expressing V561 M FGFR 1 to AZD4547. Thus, we have shown that combination therapies including FGFR and STAT3 may be able to overcome V561 M FGFR1 driven drug resistance in the clinic.As FGFRs continue to emerge as drivers of cancer, it is crucial to examine their roles in other cancer types. The Yarbrough lab identified the amplification and mutation of FGFRs as potential drivers of adenoid cystic carcinoma (ACC), a rare disease that is partially driven through the formation of cancer stem cells (CSC). In collaboration with the Yarbrough lab, I validated FGFR as a target for ACC therapy and investigated additional pathway activation in ACC CSC, using immunoblots, cell-based assays, and CyTOF.

Dissertations & Theses @ Yale University.

Books / Online / Dissertations & Theses

English

January 17, 2020

Thesis (Ph.D.)--Yale University, 2019.

Yale University.