Spheroids as a 3D Model of the Hypoxic Tumor Microenvironment.

Spheroids enable the study of tumors and tumor hypoxia using a more representative model of the physiological environment compared to 2D cell culture. Spheroids can be grown in a cell suspension or when adhered to a solid scaffold. The spheroid formation method used is dependent on cell type. Here we describe the most common spheroid formation methods, including hanging drop, low adhesion plates, hydrogel, micropatterned plates, and microfluidics. After spheroids are formed, they can be used for drug treatment trials and analyzed using Western Blots, qPCR, and microscopy. Microscopy can then be used to measure the invasiveness of cells when a basement membrane is added to spheroids and for monitoring changes in the proliferation, quiescent, and necrotic zones of spheroids.