Growth and radiation response of cells grown in macroporous gelatin microcarriers (CultiSpher-G).

Four cell lines have been cultured in macroporous gelatin microcarrier beads (CultiSpher-G) to test this as a new model of three-dimensional cell growth for use in experimental cancer therapy. A549, KB 3-1, KB 8-5 and V79 cells were successfully grown in CultiSphers, albeit with longer doubling times than observed for the respective cell type in monolayer cultures. MTT staining and histology demonstrated three-dimensional contact of cells in the microcarriers. A549 cells populated the microcarriers more densely than KB 3-1 cells, and with both cell types there is bead-to-bead variation in occupancy by cells. [3H]TdR autoradiography reveals labelled cells throughout A549 and KB 3-1 CultiSphers, with no proliferation gradient from edge to centre. Central necrosis has not been observed. A549 cells but not KB 3-1 cells demonstrated a radiation contact effect (i.e. resistance) when irradiated in CultiSphers, compared with monolayers. We conclude that CultiSphers may be a useful model for three-dimensional growth and cell contact when investigators want to investigate these phenomena without the microenvironmental gradients of spheroids.