To begin, establish the three dimensional multicellular spheroids or MCS from human lung adenocarcinoma or A549 iRFP cells. Seed the cells in 96 well ultra-low attachment round bottom spheroid micro plate using 100 microliters of complete growth medium supplemented with 0.3%collagen. Centrifuge the micro plates at 300 G for seven minutes at four degrees Celsius to facilitate the MCS formation.
After centrifugation, examine the spheroid morphology under a microscope to ensure cell aggregation. Replace 100 microliters of growth medium in each well with fresh complete growth medium every other day. While observing under a microscope, choose spheroids with a round shape and overall smooth edges, but with five to 10 rough buddings and an appropriate diameter.
Measure the iRFP fluorescence to select the MCS with fluorescent signals within one standard deviation of the average.
