Skip to main content
Fig. 5 | Cancer & Metabolism

Fig. 5

From: Cancer cell metabolic plasticity allows resistance to NAMPT inhibition but invariably induces dependence on LDHA

Fig. 5

Tryptophan was served as an alternative source for NAD production in the resistant cells. a CEM PA and CEM RES cells were treated with 5 nM FK866 for 48 h. QPRT enzymatic activity was determined. b Percentage of cell viability indicates the response of CEM PA and CEM RES cells to JPH203 (LAT1 inhibitor) at 48 h of treatment. c Synergistic effect of FK866 and JPH203 in CEM cells. Strong synergistic effect as detected by low value of combination index (CI < 1) is more evident in CEM RES compared to CEM PA. Percentage of cell viability and CI are shown in respect to DMSO. d Activation of CHOP by amino acid deprivation. Western blot depicts the level of CHOP in CEM RES cells. CEM RES cells were treated with normal RPMI-1640 (10% FBS + 2 mM l-glutamine) (lane1), 20:80 mixture of normal RPMI-1640 (10% FBS + 2 mM l-glutamine) with Eagle’s balanced salt solution (10% FBS) (lanes 2–4) in the presence of essential amino acid (EAA) or non-essential amino acid (NEAA) for 24 h. e Tryptophan (Trp) rescues amino acid sensitized CEM RES cells to JPH203. This experiment was performed in normal RPMI-1640 (10% FBS + 2 mM l-glutamine) (lane 1) and mixture medium (lanes 2–6). CEM RES cells were treated with 5 nM FK866, 10 μM JPH203 (after O/N washout) or FK866 + JPH203. Supplementation of 0.25 mM tryptophan or 1× EAA was addressed to FK866 + JPH203 co-treatment. CHOP level was determined at 24 h after treatment. fh CEM RES cells were treated with indicated conditions, and expression of CHOP and ATF4 mRNA (f), NAD(H) level (g), and ATP level (h) were determined, respectively. Experiments in ac were performed in the normal RPMI-1640 medium and in dh were performed in the mixture medium. Data were plotted as mean ± S.D. from three independent experiments (*p < 0.05, ***p < 0.001 compared to MOCK) and (ttp < 0.01, tttp < 0.001 compared among treatments)

Back to article page