Figure 1.

Workflow of metabolite extraction methods. For the one-step in-plate method, MDA-MB-231 cells grown in glass dishes were scraped in chloroform:methanol:water (1:3:1) for simultaneous extraction of polar and lipid metabolites. For the two-step in-plate method, cells were scraped in methanol:water (3:1) and chloroform was added after transfer of the mixture to a tube. For the in-tube method, cells were scraped in saline and transferred to tubes, where they were extracted in chloroform:methanol:water (1:3:1).