Abstract 3384: Rapid and automated tumor cell phenotyping based on annexin-mediated enforce blebbing response
Authors: Huang Wei , Wang Zheng , Au Dennis Wai-Yin , Tang Bingxian , Qi Baiqian , Cho William C. , Lin Yuan 
Published: March 2024

Abstract
Introduction: Accumulating evidence supports the tight correlation between the physical characteristics of cells (including morphology, mechanical, and electrical properties) with the progression of cancer. Cellular blebbing, a distinctive feature observed during apoptosis and cell migration, has gained significant recognition. However, existing tools such as atomic force microscopy and optical tweezers have limitations in terms of throughput and complexity. Microfluidics has emerged as a promising technology to overcome these limitations.
Methods: In this study, we developed a novel microfluidic device with a double-layer compression mechanism to induce controlled blebbing of cells. We implemented a convolution-based tracing program to enhance the accuracy and efficiency of cell area measurement. The device was used to examine the enforced blebbing response of two human breast cancer cell lines (MDA-MB-231 and MCF-7) and investigate the potential of blebbing as a marker for drug resistance using a human lung cancer cell line (HCC4006). Additionally, we elucidated the role of annexin-6 (A6) in enforced blebbing and its underlying mechanism.
Results: Our microfluidic device successfully implemented a double-layered design that induced cell deformation through compression from the second pressurized polydimethylsiloxane layer. The findings revealed that highly invasive cell lines, such as MDA-MB-231 and osimertinib-resistant HCC4006, required significantly higher critical compression levels compared to their non-invasive counterparts (MCF-7 cell line) or osimertinib-sensitive cells. Moreover, the drug-resistant groups exhibited a greater compression strain requirement for blebbing compared to the control group, indicating their enhanced resilience against disruptive forces and superior survivability. Prior studies have demonstrated that A6 protein is recruited to the site of membrane injury and facilitates the formation of blebs, thereby contributing to cellular repair processes. Our further investigation into the role of A6 protein demonstrated its involvement in cell blebbing. Knockdown of A6 resulted in a notable 27% reduction in cellular volume, reflecting reduced intracellular pressure, and a corresponding 1.7-fold increase in the critical compressive strain necessary for inducing blebbing.
Conclusion: Our microfluidic device allows for rapid and simultaneous testing and automated analysis of hundreds of cells, making it suitable for applications such as cell sorting, highly invasive and drug-resistant cancer cell detection, without the need for labeling. Furthermore, it serves as a powerful tool for fundamental studies of membrane and cytoskeleton dynamics. The label-free nature of the device, coupled with its high throughput capabilities, highlights its potential in future applications, including cancer monitoring and drug-resistance screening.
Citation Format: Wei Huang, Zheng Wang, Dennis Wai-Yin Au, Bingxian Tang, Baiqian Qi, William C. Cho, Yuan Lin. Rapid and automated tumor cell phenotyping based on annexin-mediated enforce blebbing response [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 3384.