Fig. 6: Resistance to RMC-7977 predominantly arises independently of MAPK activity.
From: Tumour-selective activity of RAS-GTP inhibition in pancreatic cancer
a, CNV analysis of DNA isolated from epithelial cells from RMC-7977-resistant KPC tumours (top), KPCY tumour-derived cell lines (middle) and KPF/+C naive tumours (bottom). The region highlighted in green marks chromosome 15, which includes the Myc locus. Chr., chromosome. b, CNV plots showing chromosome 15 (chr. 15) in RMC-7977-resistant KPC tumours. The vertical green line marks the Myc locus. The horizontal dashed line indicates the threshold to be called as a gain. Numbers indicate tumour identity from Fig. 5. c–f, Cell lines derived from RMC-7977-resistant or naive KPC tumours. c, Cell lines treated with DMSO or indicated concentrations of RMC-7977 for 3–5 days. Data are mean ± s.d. of three biological replicates normalized to DMSO control. Values reproduced from DMSO control (RMC-7977 alone) from Fig. 6f and Extended Fig. 7a. d, Mass spectrometry-based proteomic analysis comparing the effects of RMC-7977 and DMSO treatment in resistant K18509R (Myc gain) and naive K8484 (Myc stable). Differential protein expression signatures within each line were analysed for enrichment of published functional gene sets (MAPK, MYC and YAP–TAZ). FC, fold change; FDR, false discovery rate; NES, normalized enrichment score. e, Western blot analyses of two RMC-7977-resistant (K18745R and K18509R) and two naive (K8484 and K2293) cell lines treated with DMSO, RMC-7977 (100 nM), IAG933 (1 μM) or the combined treatment (combo) for 24 h. Vinculin and β-tubulin were used as loading controls. f, Cell lines described in e were treated with indicated concentrations of DMSO, RMC-7977, IAG933 or the combined treatment. Right, dose–response matrices show combination synergy based on cell viability at different dose pairs. Left, viability of cell lines treated with a range of RMC-7977 concentrations in combination with the indicated concentration of IAG933. Data are mean ± s.d. of 3–4 biological replicates normalized to DMSO control.
