Figure 5. Effect of cisplatin and pemetrexed on KRAS proto-oncogene, GTPase (KRAS) signaling in KRAS-dependent A549 cells. Representative western blot data of the levels of KRAS proto-oncogene, GTPase (KRAS), Raf proto-oncogene, serine/threonine kinase (RAF), mitogen-activated protein kinase kinase (MEK), phospho (p)-MEK (Ser 217/221), ERK and p-ERK (Thr 202/Tyr 204) after 72-h treatment with cisplatin (200 nM) and pemetrexed (100 nM) alone and in combination. β-Actin was used as a loading control. Representative immunoblots with quantification relative to β-actin or non-phosphorylated forms from three independent experiments are shown.