Abstract 2792: On-chip evaluation of cancer cell-extracellular vesicle interactions using a novel microfluidic microsystem (CellExoChip)

• Published in: Cancer research (Chicago, Ill.) Ill.), 2022-06, Vol.82 (12_Supplement), p.2792-2792
• Main Authors: Raju, Kruthi Srinivasa, Niu, Zeqi, Marvar, Joseph, Fortna, Shawn, Onukwugha, Nna-Emeka, Kang, Yoon-Tae, Nagrath, Sunitha
• Format: Article
• Language: English
• ISSN: 1538-7445; 1538-7445
• DOI: 10.1158/1538-7445.AM2022-2792

Introduction: Analytical methods of extracellular vesicles (EVs) is becoming an increasingly promising field of study due to them being an effective biomarker for cancers. EVs are present in various types of body fluids, which can be easily used for diagnostic purpose. Prior research has explored numerous techniques for isolating and analyzing these EVs based on their physical and biochemical properties, however, the complexity of biological samples makes conventional EV isolation difficult to exclusively extract EVs of a certain type of cell. Current downstream analysis methods lack the ability to differentiate exosomes of different origins in a sample. Recent studies suggested the presence of certain proteins in cancer exosomes that facilitates preferential uptake of the exosomes by organ-specific cancer cells, called organotropism. Using this unique property, we devised a microfluidic platform to examine the uptake of specific exosomes onto their respective progenitor cell lines, thus aiming to use the interaction for cancer diagnosis purposes. Methods: The CellExoChip was prepared following the standard PDMS-based soft lithography method. The device consists of an inlet and outlet, with dimensions of 22x22 mm with a cell capture area of about 50 mm2. The microfluidic device was functionalized by Streptavidin and the cancer cells were biotinylated with EZ-Link-NHS-Biotin to create an intense affinity between the cells and the device. We further injected dyed exosomes with different origins through the device and evaluated their specific uptake using fluorescence microscope. Results: The prepared CellExoChip successfully immobilized over 1,500 cells onto the surface and viability evaluation demonstrated that only 6.79% of the initial cells were sacrificed during the biotinylation and on-chip binding process. The average on-chip cell viability showed 75.47±7.68%. The uptake of lung cancer cell exosomes into three different cancer cell lines (lung, bladder and breast) was measured on chip. The relative uptake of lung cell exosomes by the respective lung cells was 100% compared to the bladder cells and breast cell which were 15.87% and 40.31%, respectively. We extended this specific uptake evaluation to other LungCell-LungExo combinations using H1650, A549, and in-house CTC cell line, CTCR5, and the results demonstrated the organotropism nature of the exosomes in lung cancer. Discussion and conclusion: We present a novel screening method to accurately chara