Graduation Date
Spring 5-9-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Programs
Molecular Genetics & Cell Biology
First Advisor
Adam R. Karpf
Abstract
High-Grade Serous Ovarian Cancer (HGSOC) is the most prevalent and lethal ovarian cancer histotype, characterized by aggressive clinical progression driven by the dysregulation of key signaling pathways. Central to this oncogenic network is Forkhead Box M1 (FOXM1), which has emerged as a central oncogenic regulator.
FOXM1 is a master regulator of the mammalian cell cycle, essential for embryonic development and stem cell pluripotency. While its expression in adult tissues is limited to high-proliferation niches, its pathological overexpression is a hallmark of HGSOC, where the FOXM1 transcriptional pathway is the second most frequent alteration after TP53 mutations. FOXM1 serves as a functional barrier to standard-of-care therapies, as its expression is repeatedly associated with platinum-based chemoresistance and poor patient survival. Consequently, the targeted inhibition of FOXM1 represents a potential therapeutic strategy in HGSOC.
Traditional inhibitors such as FDI-6 target the FOXM1 DNA-binding domain (DBD). However, FDI-6 is often limited by reversible drug-binding and is insufficient to abrogate FOXM1’s oncogenic function. As an alternative, induced protein degradation using a hydrophobic tagging approach provides an event-driven mechanism to irreversibly eliminate the protein of interest. By hijacking the cell’s endogenous quality control machinery, this approach shifts the occupancy-based inhibition to the targeted proteolysis of the FOXM1 protein.
To implement this hydrophobic tagging approach to target and eliminate FOXM1 in HGSOC cell lines, we developed eight FDI-6-based hydrophobic tag degraders (FDI-6-HyTDs). These compounds were synthesized by conjugating the FOXM1-binding ligand, FDI-6, to hydrophobic norbornene or adamantane moieties via varying linkers. Screening across HGSOC cell lines, OVCAR4 and CAOV3, identified 1a and 3a as the most potent compounds. In OVCAR4 cells, immunoblotting showed that treatment with 1a and 3a significantly reduced FOXM1 levels, thereby downregulating the transcriptional targets PLK1 and CCNB1. Furthermore, both compounds effectively inhibited clonogenic growth at micromolar concentrations. Mechanistic validation using the NanoBiT bioluminescence assay revealed that the loss of FOXM1 signal is potentiated by the Hsp90 inhibitor 17-AAG. Demonstrating that the loss of FOXM1 is driven by the chaperone-substrate recognition cycle. This study validates the therapeutic potential of hydrophobic tagging for the targeted elimination of FOXM1 in HGSOC cells.
Rights
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Recommended Citation
Aguilera Pineda, Tania, "Evaluating FOXM1 Hydrophobic Tag Degraders in High-Grade Serous Ovarian Cancer Cells" (2026). Theses & Dissertations. 1072.
https://digitalcommons.unmc.edu/etd/1072