Novel protein and immune response markers of human serous tubal intraepithelial carcinoma of the ovary

Ovarian cancer is the leading cause of death among gynecologic diseases in the USA and Europe. High-grade serous carcinoma (HGSC) of the ovary, the most aggressive type of ovarian cancer, is typically diagnosed at advanced stages when the 5-year survival is dismal. Since the cure rate for stage I HGSC is high, early detection of localized initial disease may improve patient outcomes. Serous tubal intraepithelial carcinoma (STIC) is considered to be a precursor lesion of HGSC. Discovery of biomarkers associated with STIC could aid in the development of an HGSC screening algorithm. Using immunohistochemical staining, we have demonstrated overexpression of UCHL1, ADAMTS13, and GAPDH in patients' STIC lesions, but not in cancer-free fallopian tubes. We additionally demonstrated a marked increase of T cells in perineoplastic stroma surrounding STIC lesions (largely CD4 + cells), but not in normal fallopian tubes and HGSC. FOXP3 + T regulatory cells are absent in STIC lesions but are present in HGSC. These observations indicate the microenvironment surrounding a STIC lesion may be immune promoting in contrast to the immune suppressive microenvironment of invasive carcinoma. In summary, we have identified UCHL1, ADAMTS13, and GAPDH as novel potentially useful markers associated with early stages of HGSC tumorigenesis and possibly contribute to STIC immunogenicity. The lack of immune suppression in the STIC microenvironment indicates that the immune system can still recognize and keep STIC controlled at this stage of the tumor development.

Abstract 5142: Elevated glycolysis in pre-malignant ovarian cancer

Ovarian cancer is the fifth leading cause of cancer death in women and the most lethal gynecologic malignancy. High-grade serous ovarian carcinoma (HGSC) originates mainly from the fallopian tube epithelium, and is characterized by TP53 mutation identified in all HGSCs as well as the fallopian tubal precursor of serous tubal intraepithelial carcinomas (STICs). The loss of a functional TP53 is an early event in the malignant transformation of fallopian tube epithelium. We have established 4 primary cell cultures of normal fallopian tube epithelial (FTE) cells, and further generated immortalized FTE cells using SV40 large plus small T antigens (FTE-TAg) to disrupt TP53 function. This model mimics the primary lesions of ovarian cancer and is suitable to identify biomarkers and molecular targets of ovarian cancer. Therefore, we compared the secretomes of primary FTE cells with that of their parental isogenic pairs FTE-TAg cells using mass spectrometry analysis. We identified 813 proteins, 228 of which were differentially expressed. Ingenuity Pathway Analysis (IPA) core analysis revealed glycolysis as a major canonical pathway. Overexpression of key enzymes of glycolytic pathway was confirmed by IHC in human STIC lesions. Molecular mechanisms of glycolysis regulation in premalignant lesion of ovarian cancer were determined. Role of glycolysis in the establishment of premalignant ovarian cancer microenvironment (PME) was characterized. Prevention approaches targeting glycolysis were tested in transgenic animal model of ovarian cancer.

Citation Format: Anna E. Lokshin, Mounia Alaoui El Azher, Liudmila Velikokhatnaya, Denise Prosser. Elevated glycolysis in pre-malignant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5142.

Ionic strength- and temperature-induced K(Ca) shifts in the uncoating reaction of rotavirus strains RF and SA11: correlation with membrane permeabilization

The hydrodynamic diameters of native rotavirus particles, bovine RF and simian SA11 strains, were determined by quasielastic light scattering. By using this method and agarose gel electrophoresis, the Ca(2+) dissociation constant, K(Ca), governing the transition from triple-layer particles (TLPs) to double-layer particles (DLPs), was shown to increase, at constant pH, as the temperature and/or the ionic strength of the incubation medium increased. We report the novel observation that, under physiological conditions, K(Ca) values for both RF and SA11 rotaviruses were well above the intracytoplasmic Ca(2+) concentrations of various cells, which may explain why TLP uncoating takes place within vesicles (possibly endosomes) during the entry process. A correlation between TLP uncoating and cell membrane permeabilization was found, as shown by the release of carboxyfluorescein (CF) from CF-loaded intestinal brush-border membrane vesicles. Conditions stabilizing the virion in the TLP form inhibited CF release, whereas conditions favoring the TLP-to-DLP transformation activated this process. We conclude that membrane permeabilization must be preceded by the loss of the outer-capsid proteins from trypsinized TLP and that physiological ionic strength is required for permeabilization to take place. Finally, the paper develops an alternative explanation for the mechanism of rotavirus entry, compatible with the Ca(2+)-dependent endocytic pathway. We propose that there must be an iterative process involving tight coupling in time between the lowering of endosomal Ca(2+) concentration, virion decapsidation, and membrane permeabilization, which would cause the transcriptionally active DLPs to enter the cytoplasm of cells.