Microgel-based in vitro tumoroid platform for real time assessment of drug sensitivity and resistance

While 3D cell cultures have been used as suitable representatives of in vivo conditions compared to 2D systems, scalability and flexibility in designing such platforms has been a major challenge1. Micron-sized 3D culture platforms offer the possibility of high throughput analysis, however major challenges exist with respect to their overall design. Technical obstacles include difficulties in supporting multiple cell types (e.g. co-cultures of cancer associated fibroblasts (CAFs) and tumor cells) as well as enabling monitoring of important parameters, such as proliferation and metabolism, in real time. Our 3D co-culture systems are based on pancreatic ductal adenocarcinoma (PDAC) spheroid models in microgels, generated by coaxial droplet microfluidics. This allows for co-culturing of cancer cells with the supporting cell types that constitute the major portion of the actual tumor. Initial optimization experiments utilized co-culture of commercial pancreatic cancer cell lines such, as L3.6pl cells, and stromal CAFs. In addition to optimizing the 3D microcultures using commercial PDAC cell lines, we are also modifying the system to take advantage of patient-matched CAFs and conditionally reprogrammed (CR) primary PDAC cells. Both drug sensitive and isogenic nab-paclitaxel resistant PDAC CR cells will be used, as recently published2. Our preliminary data showed that our platform supports rapid generation of numerous identical spheroids inside the microgel. Using microscopy under different treatment conditions (e.g the presence/absence of drugs) we can quantify spheroid growth. In addition, spatio-temporal mapping of the microenvironmental parameters such as dissolved O2, pH and K+ during growth is performed by time lapse fluorescence microscopy using fluorescent silica microparticles embedded in the matrix. This process will yield an in-depth understanding of the kinetics of growth and associated biochemical and metabolic activity for each cell type (e.g. CAF and PDAC) under different treatment conditions. Our T3D platform offers a rapid, quantifiable assessment of the behavior of patient-derived cells in providing additional details related to the changing microenvironment and may advance our understanding of treatment response and failures.