(A) Cytosolic cysteine level in LAMP1-KD and LAMP2-KD cells 5 days after siRNA exposure (n = 6), (B) Representative image of WB for stress responder ATF4 protein 5 days after siRNA exposure (n = 3), (C) Effect of cysteine (5 mM) glutamine (5 mM) and glycine (2 mM) supplementation for 24 h on intracellular GSH level (n = 6) and (D) tBHP-induced cell death after pretreatment with cysteine and glutamine (5 mM each) for 24 h. The effect of Cys and Gln amino acid supplementation was abolished with l-Buthionine-(S, R)-sulfoximine (BSO, 1 mM, 4 h pretreatment); viability checked at 24 h, tBHP at 300 µM (n = 6). Data are expressed as mean ± standard deviation (SD). *p < 0.05, **p < 0.001, ***p < 0.0001, ns: not significant, compared with other groups using ANOVA and Tukey’s multiple comparison test.