Noor A. Lokman

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 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.

Reduced Gonadotrophin Receptor Expression Is Associated with a More Aggressive Ovarian Cancer Phenotype

Follicle-stimulating hormone (FSH) and luteinising hormone (LH) play important roles in regulating cell growth and proliferation in the ovary. However, few studies have explored the expression of FSH and LH receptors (FSHR and LHCGR) in ovarian cancer, and their functional roles in cancer progression remain inconclusive. This study investigated the potential impact of both mRNA (FSHR, LHCGR) and protein (FSHR, LHCGR) expression on ovarian cancer progression using publicly available online databases, qRT-PCR (high grade serous ovarian cancers, HGSOC, n = 29 and benign ovarian tumors, n = 17) and immunohistochemistry (HGSOC, n = 144). In addition, we investigated the effect of FSHR and LHCGR siRNA knockdown on the pro-metastatic behavior of serous ovarian cancer cells in vitro. High FSHR or high LHCGR expression in patients with all subtypes of high-grade ovarian cancer was significantly associated with longer progression-free survival (PFS) and overall survival (OS). High FSHR protein expression was associated with increased PFS (p = 0.050) and OS (p = 0.025). HGSOC patients with both high FSHR and high LHCGR protein levels had the best survival outcome, whilst both low FSHR and low LHCGR expression was associated with poorest survival (p = 0.019). Knockdown of FSHR significantly increased the invasion of serous ovarian cancer cells (OVCAR3 and COV362) in vitro. LHCGR knockdown also promoted invasion of COV362 cells. This study highlights that lower FSHR and LHCGR expression is associated with a more aggressive epithelial ovarian cancer phenotype and promotes pro-metastatic behaviour.