Fibroblasts and mouse breast cancer cells can form cellular aggregates in improved soft agar culture medium.

We aimed to build cellular aggregates of TS/A and normal fibroblasts (LX-2) or CAFs (ME-iLX-2), verifying the value of this model in the screening of anticancer drugs and demonstrating the effect of CD44 on aggregate formation. We improved soft agar culture medium to coculture CAFs (NFs) and TS/A and compared the amount and area of cellular aggregates. Eugenol was added to this model to test its value. The transcription of human CD44 was analyzed through RT-qPCR. Cellular aggregates were formed, and both the amount and area of aggregates in the TS/A-ME-iLX-2 coculture group were higher than those in other groups. The eugenol inhibited the formation of TS/A-fibroblasts aggregates. Human CD44 was highly transcripted in TS/A-ME-iLX-2 aggregates. Cocultured cellular aggregates of fibroblasts and TS/A were successfully formed in the improved soft agar culture medium, and the promotion effect of CAFs on cancer cells was further confirmed. The eugenol test showed its value in the screening of anticancer drugs. The RT-qPCR results demonstrated the important effect of CD44 on aggregate formation.