Adapting Cell Lines to Serum-Free Culture Conditions.

Successful cell culture relies on media containing xenogenic components such as fetal bovine serum to support continuous cell proliferation. Here, we report a serum-free culture condition that supports the growth and proliferation of S2R+ and Kc167 cell lines. Importantly, the gradual adaptation of S2R+ and Kc167 cells to a media lacking serum was supported by supplementing the media with adult soluble extract, commonly known as fly extract. The utility of these adapted cells lines is largely unchanged. The adapted cells exhibited robust proliferative capacity and a transfection efficiency that was comparable to control cells cultured in serum-containing media. Transcriptomic data indicated that the S2R+ cells cultured with fly extract retain their hemocyte-specific transcriptome profile, and there were no global changes in the transcriptional output of cell signaling pathways. Our metabolome studies indicate that there were very limited metabolic changes. In fact, the cells were likely experiencing less oxidative stress when cultured in the serum-free media supplemented with fly extract. Overall, the cell culture conditions reported here consequently provide researchers with an alternative and physiologically relevant resource to address cell biological research questions.