Fig. 1.

Identification of lorlatinib to synergize with GXP4 inhibition in melanoma.

(A) Schematic of the identification of clinically applicable drug from the FDA-approved drug library that sensitize melanoma to RSL3. (B-C) Summary scatter plot of CDI in A375 (B) and SK-MEL-28 (C) cells indicating lorlatinib as one of the most potential drugs that synergize with RSL3. Indicated was the drugs that have been reported to synergize with RSL3. (D-E) Percentage of inhibition rate was presented in a series of 6 × 6 screening experiments in A375 (D) and SK-MEL-28 (E) cells. Synergy was evaluated by Chou-Talalay combination index (CI) for lorlatinib and RSL3 across the indicated cell lines. The x axis of CI plots represents fraction affected. (F) GPX4 protein levels were quantified by western blotting in control (sgCtrl) and GPX4 deficient (sgGPX4) cells. (G) Cell viability of GPX4 deficient cells treated with different concentrations of lorlatinib for 12 h. (H) Cell morphological features at different time point after the indicated treatment. Lorlatinib, 5 μM; RSL3, 2.5 μM. Images were taken at 200X magnification. P values were calculated using two-way ANOVA analysis. ***, P < 0.001.