A. CAF and WI-38 cells pretreated with EVs from MDA-MB-231 or MCF10A cells, or PBS for 48 h were unstarved (U) or starved (S) for 2 h in EBSS prior to addition of a mixture of leucine, arginine, and lysine (LRK) or a cocktail of essential AAs (EAA). Cells were analyzed by Western blot analysis in a time course as indicated. 