Abstract 2748: Single cell biomechanical profiling of the metastatic potential of MDA-MB-231 cells
Authors: Habli Zeina , Zantout Ahmad , Hajj Nadine Al , Saab Raya , El-Sabban Marwan , Khraiche Massoud L. 
Published: March 2024

Abstract
Cancer metastasis is a multistep complex process accompanied by changes in the mechanical properties of cancer cells, such as adhesion, viscoelasticity, deformability, and motility. Connexin 43 (Cx43), a gap junction protein with a putative tumor suppressor function, plays a pivotal role in Epithelial to Mesenchymal transition (EMT). It affects cell motility indicators and promotes cytoskeleton reorganization and, ultimately, metastasis when downregulated, corroborating resistance to chemotherapy. The lack of universal markers that can predict the metastatic ability of cancer cells necessitates the evaluation of parameters, such as cell adhesion, viscoelasticity, and stiffness, to serve as unique biophysical metrics that predict cancer cell metastatic potential and elucidate how metastasis and cell mechanics are coupled. Therefore, we utilized fluidic-based single-cell force spectroscopy (SCFS) and Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) to measure the mechanical properties of single cancer cells with different metastatic potential. To explore the relationship between cell mechanics and metastatic cell behavior, we quantitatively demonstrate the progression of cancer cell biomechanics across different metastatic states using MDA-MB-231 breast cancer cells with varying connexin 43 (Cx43) expression as a model of cells with varying metastatic potential. We measured, at a single-cell level and in real-time, the adhesion and viscoelastic properties of MDA-MB-231 cells and their response to chemotherapy. Our data show that cells with higher metastatic potential (down-regulated Cx43 expression) exhibited a softer, less adherent, and more viscoelastic phenotype, consistent with their metastatic state when in clusters compared to cells at the lower spectrum of metastatic potential (up-regulated Cx43 expression). These mechanical biomarkers are significantly absent in single cells outside of a cluster. Of particular interest, we also observed significant cellular stiffening upon treatment with docetaxel (DTX), a chemotherapeutic agent that targets microtubules, with a rapid and profound response of highly aggressive cells when compared to cells with attenuated metastatic potential. Such treatment schemes could render cancer cells less deformable, potentially impeding their ability to invade and metastasize to other tissues. Our study demonstrates a unique quantitative metric that unfolds biomechanical markers for discerning the metastatic state of cancer cells. Our data represents a stepping stone to understanding how mechanical changes in cancer cells may determine how cancer progresses and responds to chemotherapeutic agents and may provide novel modalities to inhibit metastasis.
Citation Format: Zeina Habli, Ahmad Zantout, Nadine Al Hajj, Raya Saab, Marwan El-Sabban, Massoud L. Khraiche. Single cell biomechanical profiling of the metastatic potential of MDA-MB-231 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2748.