FIGURE 5

Dual SHP2/ALK inhibition resensitizes lorlatinib-resistant ALK^F1174L cells and reduces tumor regrowth. A, Kelly cells were treated with increasing doses of lorlatinib (0.1–5.0 µmol/L) or DMSO over 90 days to select for subpopulations of lorlatinib-resistant (Kelly-LR) or -sensitive (Kelly-S) cells. Cell lines were maintained under chronic exposure to lorlatinib or DMSO. Created with BioRender.com. Cell viability (alamarBlue) and IC₅₀ was assessed in Kelly-S and Kelly-LR cells treated with increasing concentrations of lorlatinib alone (B) or lorlatinib plus TNO155 (C) for 72 hours. A maximum of 150 µmol/L of either or both drugs was serially diluted (1:3) to assess wide-range dose efficacy (0–150 µmol/L, doses of 0.0076, 0.0228, 0.0685, 0.205, 0.617, 1.851, 5.555, 16.666, 50, and 150 µmol/L). D, Western immunoblots of Kelly-S and Kelly-LR cells treated with TNO155 (1.5 µmol/L), lorlatinib (1 µmol/L), or combination treatment for 6 hours. Tumor growth (E) and Kaplan–Meier survival curves (F) of Kelly xenografts treated with two rounds of low-dose vehicle control (n = 4), TNO155 (n = 3), lorlatinib (n = 5), or combination treatment (Combo, n = 4) for 4 weeks each, with a 3 week drug break in between each round. **, P < 0.01; ***, P < 0.001.