Fig 1. Optimization of co-culture system.

A) Optimization of the tumor cell: fibroblast ratio. Cancer cells and fibroblasts (MRC5) were cultured in 96 well-well plates as either monocultures or co-cultures as described in the cell viability assay in the Materials and Methods section. Different ratios of tumor cells to fibroblasts were used as indicated. Cell viability was measured on day 5. We observed that the cell viability on day 5 was the highest at tumor cell: fibroblasts ratio of 1:1.5) on day 5. B) Optimization of the co-culture duration. Cancer cells and fibroblasts (MRC5) were cultured in 96-well plates as monocultures or co- cultures as described in the cell viability assay in the Materials and Methods section. The tumor cells and fibroblasts were co-cultured at a ratio of (1:1.5), and cell viability was measured on days 3, 5 and 7. The viability in of the co- cultured cells increased from day 3 to day 5 and then decreased slightly on day 7.