Abstract LB437: Development of a bladder cancer-on-a-chip assay to assess the invasive potential of bladder cancer cells
Authors: Ewell Desiree , Vue Nita , Moinuddin Sakib , Sarkar Tanoy , Ahsan Fakhrul , Vinall Ruth L. 
Published: April 2024

Abstract
Goals: The primary goal of this study was to develop a 3D functional bioassay to assess the relative invasiveness of bladder cancer cells. This model will support the testing of migrastatic drugs and investigation of the molecular mechanisms which allow for bladder cancer cell invasion to occur.
Methods: Our model uses an organ-on-a-chip platform to assess bladder cancer cell invasiveness. This platform supports 3D culture of cells as well as pharmacokinetic studies. Our chips were designed to have a center channel to hold cells supported in Matrigel®, 2 adjacent side channels filled with Matrigel® only, and 2 outer media channels. Total cell and Matrigel® side channel length is 3 cm, channel height is 150 µm, and each channel width is 1 mm. Four bladder cancer cell lines (MB49, T24, J82, RT4) and cells isolated from a mouse bladder were used to develop our model. Cells were mixed with 1:1 media and Matrigel® and a total of 5,000 cells/µl introduced into the center channel. The 2 adjacent side channels were then filled with Matrigel®. The upper media channel was filled with 10% FBS cell culture media while the lower media channel was filled with 1% charcoal stripped cell culture media to thereby create a nutrient and growth factor gradient. Invasion of cells into the Matrigel®-containing side channels was assessed every 24 hours. Using the ImageXpress machine (Molecular Dynamics), we measured the furthest distance travelled by the cells. The chips were then fixed in 4% paraformaldehyde and stained using FITC-phalloidin and DAPI.
Results: J82 and T24 cell lines, derived from patients with muscle invasive bladder cancer, and the MB49 cell line, a highly invasive mouse bladder cancer cell line, started invading into the Matrigel® side channels within 24 hours. T24, J82, and MB49 cells moved a maximum of 110, 87, and 170 µm by 48 hours, respectively. In contrast, RT4 cells, derived from a patient with non-invasive bladder cancer, took 48 hours to invade the Matrigel® channels and only invaded a maximum of 3 µm. Cells isolated from a mouse bladder did not invade into the Matrigel® side channels but survived within the chips for over 20 days. Staining of chips with DAPI and FITC-phalloidin allowed for clear visualization of cells and the actin cytoskeleton and demonstrated that immunostaining of cells within chips is possible.
Conclusions: Our chip model allows for studying the invasiveness of bladder cancer cells and immunostaining experiments which can be used to assess the molecular mechanisms which drive invasion. It can also support the growth and assessment of primary cells. This model has the potential to improve bladder cancer patient treatments and outcomes by providing a physiologically relevant system to test new and existing drug combinations and to better understand the molecular mechanisms which drive bladder cancer cell invasion.
Citation Format: Desiree Ewell, Nita Vue, Sakib Moinuddin, Tanoy Sarkar, Fakhrul Ahsan, Ruth L. Vinall. Development of a bladder cancer-on-a-chip assay to assess the invasive potential of bladder cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB437.