Multicellular tumor spheroid cultures for in vitro testing of focused ultrasound-based anticancer therapies
Multicellular tumor spheroid cultures (MCTS), have a wide variety of uses in the field of cancer treatment. Current methods, however, do not provide spheroids adequate large for therapy testing. In order to circumvent this problem, a bioreactor made using Polydimethylsiloxane (PDMS) was constructed to allow the adequate growth of spheroid clusters. Liver Hepatic Carcinoma cells (Hep G2) and Anaplastic Thyroid Carcinoma (SW 1736) were cultured and isolated. They were then further matured using the “hanging drop” method, involving spheroid formation using gravity. The optimal growth time for hanging drop cultures was determined to be 72 hours. PDMS wells of different diameter were then constructed using a 24-well plate as a base, and clusters of cells were transferred into them for MCTS formation. The wells were fabricated using PDMS as a mold, then carving out wells for cell growth. Development of the spheroids in the bioreactor was monitored using microscopy paired with various staining techniques, and measurements and media changes were done daily. Cell cluster volume and height were analyzed as a function of PDMS well diameter. Optimum spheroid formation occurred in 5mm diameter wells, with peaking growth around 10 days. Further research was done regarding cancer cells and HIFU (High Intensity Focused Ultrasound) and Ethanol treatments, as tests of combination cancer therapies. Cells were first treated as cell pellets, then using the spheroid method above. The use of combination therapies proved more effective than either therapy alone. Chemo-ablation is also an upcoming therapy method to be used in combination therapies. This research can be used as a starting point for larger spheroid formation, and eventually in vivo testing of cancer therapies. Further analysis can be done to compare these models for comparison of shape, viability, and the effects of anti-cancer treatments.