Date of Graduation
5-2015
Document Type
Dissertation (PhD)
Program Affiliation
Cancer Biology
Degree Name
Doctor of Philosophy (PhD)
Advisor/Committee Chair
Samuel C. Mok, PhD
Committee Member
Robert C. Bast, Jr., MD
Committee Member
Russell R. Broaddus, MD, PhD
Committee Member
Anil K. Sood, MD
Committee Member
Kwong Kwok Wong, PhD
Abstract
Advanced stage ovarian cancer is the most lethal gynecologic malignancy. No major improvement on patient survival has been achieved in the past decade. Therefore, identification of predictive or prognostic markers and further understanding of the molecular mechanisms in ovarian cancer progression are of paramount importance.
While cancer cells have always been the targets for the identification of prognostic and predictive markers, the potential for developing new diagnosis and treatments based on the tumor supporting stromal microenvironment is relatively unexplored. Using transcriptome profiling analysis on microdissected stromal and epithelial components of normal and malignant ovarian tissues, we identified a gene signature in the fibroblastic stromal component of the tumor tissue. Among the differentially expressed genes identified in microdissected cancer associated fibroblasts, microfibrillar associated protein 5 (MFAP5), which showed 10 folds increase in expression showed significant association with poorer overall survival in patients with high grade serous ovarian cancer. In addition, we identified a positive correlation between stromal MFAP5 expression and intratumor microvessel density, suggested a pro-angiogenic role of MFAP5. This study aims at delineating the functional roles and mechanisms by which stromal MFAP5 modulates ovarian tumor progression and angiogenesis and investigating the potential of targeting stromal MFAP5 as therapy for ovarian cancer.
Functional studies demonstrated that MFAP5 stimulated motility and invasion potential of ovarian cancer cells and microvascular endothelial cells through the binding of αvβ3 integrin receptor. In vivo, targeting stromal MFAP5 using siRNA incorporated chitosan nanoparticles significantly reduced tumor growth, metastasis and intratumoral microvessel density. Further, pathway analyses and western blot analyses demonstrated that CAF-derived MFAP5 modulates ovarian cancer cell motility and invasion potential through the calcium dependent FAK/CREB/TNNC1 signaling pathway and MFAP5 enhanced endothelial cell motility potential and permeability via focal adhesion and stress fiber formation by activating the calcium dependent FAK/ERK/LPP signaling pathway. Finally, monoclonal anti-MFAP5 antibodies were developed. These antibodies demonstrated inhibitory effects on tumor growth and improved paclitaxel bioavailability via the reduction of intratumoral microvessel leakiness.
To conclude, our results demonstrated the important roles of MFAP5 in promoting ovarian tumor progression and the potential of targeting stromal MFAP5 as a novel therapeutic approach for ovarian cancer.
Keywords
MFAP5, Ovarian Cancer, Tumor microenvironment, Cancer associated fibroblast, Angiogenesis, Monoclonal antibody