Western blot of parental YUMAC and YURIF, as well as dual-resistant YUMACdr and YURIFdr, shows significant downregulation of new protein translation at low concentrations in YUMAC and YURIF but only at the highest concentrations in YUMACdr and YURIFdr. Erk, extracellular signal-regulated kinase; MEK, MAPK/ERK kinase; p90RSK, p90 subfamily of ribosomal S6 kinase; RPS6, ribosomal protein S6.