Abstract A53: [10]-gingerol interferes with the adhesion of MDA-MB-231 tumor cells to extracellular matrix

Abstract

Abstract Breast cancer is one of the most common malignant diseases in women worldwide. In developing countries, it is the second highest cause of death in women. Triple-negative breast cancer (TNBC) represents the approximately 15% of breast cancers that lack expression of estrogen (ER) and progesterone receptors (PR) and do not exhibit amplification of the human epidermal growth factor receptor 2 (HER2) gene. Metastatic process is described as a cascade of events. Normal cells are transformed into tumor cells due to mutations in genes that regulate critical pathways, producing an imbalance between proliferation and cell death that eventually leads to the formation of a primary tumor. Further interactions with the stromal microenvironment surrounding tumor cells and extracellular matrix (ECM) proteins contribute to the formation of new vessels. These interactions facilitate tumor cell invasion of surrounding tissues, intravasation through newly formed vessels, and dissemination to other tissues, to form secondary tumors. To treat metastasis from breast and many other cancer types, chemotherapy is one of the most extensively used methods. However, its efficacy and safety remain a primary concern, as well as its toxicity and other side effects. Thus, there is increasing interest in naturally occurring cancer antitumor agents. Ginger (Zingiber officinale Roscoe) is widely used worldwide as a food, spice, and herb. Recently we have demonstrated that [10]-gingerol is able to revert malignant phenotype in breast cancer cells in 3D culture and, moreover, to inhibit the dissemination of TNBC to multiple organs including to lung, bone, and brain, in spontaneous and experimental in vivo metastasis assays. The aim of this work was to investigate the effects of [10]-gingerol on the adhesion properties of MDA-MB-231 cells to the extracellular matrix (ECM). We hypothesized that, at least in part, these effects are mediated through [10]-gingerol interactions with αVβ3 integrin. Human MDA-MB-231 breast tumor cells were obtained from ATCC and maintained at 37°C, 5% CO2 in Dulbecco’s Modified Eagle Medium, containing FBS 10%). Ninety-six well plates were coated vitronectin (1µg/well) dissolved in adhesion buffer at 4ºC overnight, blocked for 2h with 1% BSA, and the wells washed with 100μL of adhesion buffer. MDA-MB-231 cells (5x105/mL) were pretreated for 30min with [10]-gingerol (1-100μM) in a humidified incubator with 5% CO2 at 37°C and 100µL of cell suspension plated into wells and incubated as above for a further 1 hour. Nonadherent cells were gently removed by washing and adherent cells were fixed with 100µl of 4% paraformaldehyde solution for 20min, stopped with PBS-Glycine, stained with DAPI, and counted in a HCS microscope. Data from docking were analyzed in AutoDock plugin for PyMOL and the two-dimensional scheme of interaction was obtained by LiPlot+.The electrochemical study of the interaction between [10]-gingerol and αVβ3 integrin was performed using disposable electrochemical cells (DCell), which are composed by a carbon working electrode, an Ag|AgCl pseudo-reference electrode, and a carbon counter electrode. Measurements were carried out employing the potentiostat DropSens 8000 and Dropview software 8400. The interaction of [10]-gingerol and αVβ3 integrin was evaluated by the changes in the [10]-gingerol electrochemical responses. For this, different amounts of standard αVβ3 integrin solution in PBS pH 7.0 were added and mixed homogeneously with a solution composed of 10µM [10]-gingerol. The differences of peak current were used to demonstrate the changes of electrochemical responses. We found that [10]-gingerol was able to inhibit TNBC cell adhesion to vitronectin ECM with more specificity compared to the other ECM components investigated, demonstrating that this compound interferes in this step of the metastatic process. We proposed that these effects could be, at least in part, resulting from the interaction between [10]-gingerol and αVβ3 integrin, as demonstrated by electrochemical and docking studies. Citation Format: Angelina Maria Fuzer, Ana Carolina B. M. Martin, Rebeka Tomasin, Carolina Venturini Uliana, Amanda Blanque Becceneri, Rafael L. Bressani Lino, James Almada da Silva, Paulo Cezar Vieira, Heloisa Sobreiro Selistre de Araújo, Rodolpho de Campos Braga, Ronaldo Censi Faria, Marcia Regina Cominetti. [10]-gingerol interferes with the adhesion of MDA-MB-231 tumor cells to extracellular matrix [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A53.