UC Santa Cruz

Ovarian cancer (OvC) is the most lethal gynecologic malignancy, with high-grade serous ovarian cancer (HGSOC) being the most common and deadly subtype. HGSOC is characterized by an aggressive metastatic pattern, originating in the fallopian tube where fallopian tube epithelial (FTE) cells transform and metastasize first to the ovary and then to the omentum. This metastatic behavior suggests that the ovary and omentum are preferred sites for HGSOC metastasis, though the reasons for this preference are not well understood and are likely influenced by metabolite exchange between OvC cells and healthy tissues.Mass spectrometry imaging (MSI) is a powerful technique for visualizing the spatial distribution of small molecules within biological samples. Dr. Katherine Zink, a previous graduate student, developed an innovative MSI protocol for evaluating 3D cocultures of tumorigenic FTE cells and murine explant tissues. Using this protocol, Dr. Zink identified norepinephrine (NE), a chemoattractant secreted from the ovary during primary metastasis. This thesis builds on her work by further investigating NE’s role in metastasis and adapting the MSI protocol for use with omental tissue to study secondary metastasis. MSI and quantitative liquid chromatography-mass spectrometry (LC-MS) were used to investigate chemical exchanges in the metastasis of HGSOC to both the ovary and omentum. An LC-MS based assay for quantifying NE was developed to assess NE secretion levels in ovarian cocultures with various OvC cell lines, aiming to relate NE production to cancer-specific pathway modifications or survival times in murine models. Although NE production varied in ovarian cocultures and did not consistently correlate with specific genetic modifications or survival times, data suggested that TP53 mutations might be associated with increased NE production and responsiveness to NE signaling. The quantitative assay also assessed NE levels in human follicular fluid (FF) samples spiked into cultures of human tumorigenic FTE cells, indicating a possible correlation between NE levels and the development of anoikis resistance in human tumorigenic FTE cells. During this dissertation, our lab transitioned from using a Bruker AutofleX MALDI-TOF mass spectrometer (MS) to a Bruker timsTOF fleX MS for MSI analysis. The new instrument's sensitivity to height differences on coculture sample surfaces necessitated adapting the sample preparation protocol. An automated spinner for sample desiccation was developed, improving MSI data quality and protocol robustness. After optimization, the MSI protocol identified the FTE secreted factor that stimulates NE secretion from the ovary during primary metastasis. Additionally, the MSI protocol was adapted for use with omental tissue to study secondary metastasis, revealing several upregulated signals in OvC cell/omentum cocultures. Increased BCAA catabolism was observed at the interface of OvC cells and omental tissue in coculture, and ion suppression was found to impact MSI data. Overall, this thesis enhances our understanding of metabolic exchanges and their role in the metastatic progression of HGSOC, providing insights that could inform future research and therapeutic strategies.