ORCID ID
Graduation Date
Spring 5-10-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Programs
Cancer Research
First Advisor
Justin Mott, MD, PhD
Abstract
Cholestasis, altered or absent bile flow, is associated with poor survival in patients with cholangiocarcinoma, an aggressive cancer of the biliary epithelium. Changes in bile flow often result in stricture or obstruction. Experimental cholestasis promoted tumor growth and progression. However, studies are needed that directly assess the mechanical interaction between bile flow, or bile shear stress, and cholangiocarcinoma signaling. We hypothesized that cholestasis and absent bile shear stress activated cancer signaling and increased aggressive cellular behaviors such as proliferation and migration. Fluid shear stress approximating bile flow was applied by orbital culture plate method and compared to identical static culture conditions. Static culture caused Akt phosphorylation and activation, β-catenin nuclear translocation, and increased markers of epithelial-to-mesenchymal reprogramming activity. Static culture increased tumor cell migration that was consistent and independent of the direction of fluid flow. Static culture increased tumor cell proliferation. These studies utilized a phospho-protein sandwich-ELISA, immunoblots of whole cell lysates and of subcellular fractions from tumor cell lines, and a novel migration assay to test cholangiocarcinoma cell responsiveness to fluid shear stress. Stasis further activated signaling via FGF19 and its cognate receptor, FGFR4, that provided apoptosis resistance, motivated cell migration, and regulated cholangiocarcinoma tumor growth. FGF19 was secreted into the media by static cells, a possible mechanical regulation of FGF19 and stabilization of FGFR4 in regions of cholestasis. Pan-FGFR inhibition and FGFR4 inhibition increased TRAIL-induced tumor cell death and reduced proliferation. Preferential FGFR4 inhibition also enhanced TRAIL-induced cell death in combination with gemcitabine/cisplatin chemotherapy, the standard of treatment for this cancer. Initial therapeutic efficacy by targeting the FGF19/FGFR4 axis in an in vivo model of cholestatic cholangiocarcinoma led to tumor weight reduction. Together, these data demonstrated the regulation of cholangiocarcinoma by mechanical forces modeling cholestasis and acting through receptor tyrosine kinase receptor signaling, Akt, β-catenin, and a novel mechanical-kinase pathway. Restoring mechanosensory responses to patients with cholestatic tumors may renew interest in a therapeutic paradigm whereby bile flow is restored as an approach in cholangiocarcinoma to return cells toward a healthy biliary epithelium program.
Recommended Citation
Oleksijew, Andrew, "Cholestasis and Fluid Flow are Biomechanic Regulators of Cholangiocarcinoma Progression" (2025). Theses & Dissertations. 925.
https://digitalcommons.unmc.edu/etd/925
Comments
2025 Copyright, the authors