Betul Kara

Mechanisms of Alzheimer’s disease (AD) and its putative prodromal stage, amnestic mild cognitive impairment (aMCI), involve the dysregulation of multiple candidate molecular pathways that drive selective cellular vulnerability in cognitive brain regions. However, the spatiotemporal overlap of markers for pathway dysregulation in different brain regions and cell types presents a challenge for pinpointing causal versus epiphenomenal changes characterizing disease progression. To approach this problem, we performed Weighted Gene Co-expression Network Analysis and STRING interactome analysis of gene expression patterns quantified in frontal cortex samples (Brodmann area 10) from subjects who died with a clinical diagnosis of no cognitive impairment, aMCI, or mild/moderate AD. Frontal cortex was chosen due to the relatively protracted involvement of this region in AD, which might reveal pathways associated with disease onset. A co-expressed network correlating with clinical diagnosis was functionally associated with insulin signaling, with insulin (INS) being the most highly connected gene within the network. Co-expressed networks correlating with neuropathological diagnostic criteria (e.g., NIA-Reagan Likelihood of AD) were associated with platelet-endothelium-leucocyte cell adhesion pathways and hypoxia-oxidative stress. Dysregulation of these functional pathways may represent incipient alterations impacting disease progression and the clinical presentation of aMCI and AD.

The high mortality of OvCa is caused by the wide dissemination of cancer within the abdominal cavity. OvCa cells metastasize to the peritoneum, which is covered by mesothelial cells, and invade into the underlying stroma, composed of extracellular matrices (ECM) and stromal cells. In a study using a three-dimensional quantitative high-throughput screening platform (3D-qHTS), we found that β-escin, a component of horse chestnut seed extract, inhibited OvCa adhesion/invasion. Here, we determine whether β-escin and structurally similar compounds have a therapeutic potential against OvCa metastasis. Different sources of β-escin and horse chestnut seed extract inhibited OvCa cell adhesion/invasion, both in vitro and in vivo. From a collection of 160 structurally similar compounds to β-escin, we found that cardiac glycosides inhibited OvCa cell adhesion/invasion and proliferation in vitro, and inhibited adhesion/invasion and metastasis in vivo. Mechanistically, β-escin and the cardiac glycosides inhibited ECM production in mesothelial cells and fibroblasts. The oral administration of β-escin inhibited metastasis in both OvCa prevention and intervention mouse models. Specifically, β-escin inhibited ECM production in the omental tumors. Additionally, the production of HIF1α-targeted proteins, lactate dehydrogenase A, and hexokinase 2 in omental tumors was blocked by β-escin. This study reveals that the natural compound β-escin has a therapeutic potential because of its ability to prevent OvCa dissemination by targeting both cancer and stromal cells in the OvCa tumor microenvironment.

The cancer cells, stromal cells and stroma in the tumor microenvironment contribute to cancer metastasis and drug resistance. Therefore we applied an organotypic, robust and reliable assay for quantitative high throughput screening (qHTS) in drug discovery. This 1536-well HTS culture contains primary human mesothelial cells, fibroblasts, fibronectin and collagen type I and reproduces the human ovarian cancer (OvCa) metastatic microenvironment. The qHTS assay identifies small molecule compounds that inhibit OvCa adhesion/migration/invasion to the organotypic metastatic microenvironment. Over 44,000 small molecules were screened in the primary qHTS assay. A counter screen was performed to eliminate any compounds toxic to the mesothelial cells or fibroblasts within the metastatic microenvironment. The activity of hit compounds was confirmed using five OvCa cell lines, and validated in secondary in vitro and in vivo biological assays. The active compounds directly inhibit at least two of three OvCa functions: adhesion, invasion and growth. In vivo, these compounds prevent OvCa adhesion/invasion and metastasis, and improve survival in mouse models. Collectively, these data indicate that the three compounds, two tyrosine kinase inhibitors and one novel compound, identified using an complex organtoypic culture of the tumor microenvironment for qHTS are potential therapeutics for OvCa metastasis. Citation Format: Hilary A. Kenny, Madhu Lal, Min Shen, Dominik Nahotko, Sarah Fazal, Siquan Chen, Chun-Yi Chiang, Betul Kara, S. Diane Yamada, Kyle Brimacombe, Juan Marugan, Marc Ferrer and Ernst Lengyel. QUANTITATIVE HIGH-THROUGHPUT SCREENING USING AN ORGANOTYPIC MODEL IDENTIFIES TWO KINASE INHIBITORS THAT INHIBIT OVARIAN CANCER METASTASIS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-097.