Zoe K. Price

Protease-Activated Receptor F2R Is a Potential Target for New Diagnostic/Prognostic and Treatment Applications for Patients with Ovarian Cancer

Effective treatment of ovarian cancer is limited by late-stage detection and chemotherapy resistance. There is a clinical need for the discovery of novel molecular targets to enable the development of innovative theranostic approaches. We investigated the coagulation factor II receptor/protease-activated receptor 1 (F2R/PAR1) as a potential diagnostic/prognostic biomarker and therapeutic target for ovarian cancer treatment. Public RNA sequence and DNA microarray data were used to analyze F2R gene expression in ovarian cancers, with protein expression confirmed in tumor samples by flow cytometry, immunofluorescence, and immunohistochemistry (IHC). Functional assays were conducted to study effects of F2R suppression on tumor progression. Our analysis confirmed elevated F2R mRNA and protein expression in ovarian cancers, notably in patients with metastatic and chemotherapy-resistant disease. Kaplan–Meier survival analysis demonstrated an association between high F2R protein detection and reduced progression-free survival. F2R suppression in ovarian cancer cell lines reduced tumor cell motility, invasion, spheroid formation, and metabolism and enhanced carboplatin sensitivity. F2R is a compelling diagnostic/prognostic and therapeutic target that could be used to treat chemotherapy-resistant and metastatic disease. The evaluation of novel F2R targeting strategies, using antibody-conjugated drugs or F2R ligand-decorated drug carriers, could lead to the development of effective therapeutics for patients with ovarian cancer.

Identification of Sphingosine Kinase 1 as a Novel Protein Regulated by High Molecular Weight Hyaluronan in Ovarian Cancer

ABSTRACT The effects of hyaluronan (HA) in cancer are widely studied; however, the role of different molecular weight HA is poorly understood. Identifying novel proteins regulated by different molecular weight HA may highlight novel therapeutic targets. Proteomics analysis was performed to identify novel proteins regulated by different molecular weight HA (27, 183 and 1000 kDa) in ES‐2 ovarian cancer cells over‐expressing Notch3 intra‐cellular domain. Our analyses identified sphingosine kinase 1 (SPHK1), a novel protein regulated by 183‐ and 1000‐kDa HA. Utilising online databases and high‐grade serous ovarian cancer (HGSOC) patient tissue microarray cohorts, we assessed the relationship between SPHK1 expression and ovarian cancer metastasis, recurrence and patient outcome. We assessed the effects of the HA synthesis inhibitor 4‐methylumbelliferone (4‐MU) on SPHK1 expression in ovarian cancer cells and HGSOC patient tissues using ex vivo tissue explant assays. SPHK1 was significantly increased in ovarian cancer compared to normal tissues, elevated in metastatic and recurrent HGSOC tissues and associated with poor patient outcome. 4‐MU significantly inhibited SPHK1 expression in ovarian cancer cells (ES‐2, CaOV3 and A2780) and HGSOC patient tissues. This study highlights a link between HA and SPHK1 expression in ovarian cancer. Our findings confirm an adverse effect on ovarian cancer prognosis. SPHK1 constitutes a novel promising target against ovarian cancer that warrants further investigation.

Identification of Proteins Associated with Ovarian Cancer Chemotherapy Resistance Using MALDI-MSI

Ovarian cancer is the most lethal gynecological cancer. Up to 75% of cases are high-grade serous ovarian cancer (HGSOC) that have high chemosensitivity to first-line platinum-based therapies. However, 75% of patients will become chemoresistant following relapse. The underlying mechanism for developing resistance to chemotherapy in HGSOC is poorly understood. In this study, we employed Matrix-Assisted Laser Desorption/Ionization–Mass Spectrometry Imaging (MALDI-MSI) on matching formalin-fixed paraffin-embedded (FFPE) HGSOC tissues at the time of diagnosis and following relapse with chemotherapy-resistant disease (n = 4). We identified m/z values that were differentially abundant in the matching diagnosis and relapse HGSOC tissues. These were matched to proteins using nano-liquid chromatography tandem mass spectrometry (LC-MS/MS). We identified upregulated proteins in the HGSOC relapse tissues, including COL12A1, FUBP1, PLEC, SLC4A1, and TKT. These proteins were validated by immunohistochemistry (IHC) and gene expression using online databases. IHC showed COL12A1, FUBP1, PLEC, SLC4A1, and TKT protein abundance were significantly elevated in HGSOC relapse tissues compared to matching tissues at diagnosis. COL12A1, FUBP1, PLEC, and TKT mRNA expression levels were significantly increased in HGSOC compared to normal ovary and associated with poor prognosis in HGSOC. We confirmed that higher protein abundance of both COL12A1 and PLEC correlated with reduced progression-free survival in HGSOC patients. Furthermore, both COL12A1 and PLEC mRNA and protein levels were significantly associated with chemotherapy resistance. In summary, using MALDI-MSI, we have identified proteins, including COL12A1 and PLEC, associated with chemotherapy resistance to be further evaluated as HGSOC biomarkers and/or therapeutic targets.