Journal: bioRxiv
Article Title: Mutation-Resolved Drug Sensitivity Atlas Reveals Broad RAS(ON) Inhibitor Vulnerabilities and a STAT3 Co-Dependency in NRAS-Mutant Melanoma
doi: 10.64898/2026.02.18.706707
Figure Lengend Snippet: STAT3 is required for survival of melanoma cells treated with active RAS(ON) inhibitors. (A) Signaling responses to RAS(ON) inhibition in isogenic MeWo cells expressing WT, Q61R, Q61K, or Q61L NRAS. Bubble plot summarizing Western blot–derived signaling changes after 8-hour treatment with the indicated inhibitors. Band intensities were quantified by densitometry, normalized to vehicle controls (set to 100%), and represented as bubble size. Cells were treated with dose ranges appropriate for each inhibitor class: sotorasib and adagrasib (0.1, 1, 10 μM); ADT-007, BI-2865, RMC-6236, and RMC-7977 (0.01, 0.1, 1, 10 μM). (B) Western blot analysis of phospho-STAT3 (Tyr705) in MeWo isogenic cells treated with 1 μM RMC-6236 or RMC-7977 for 0, 12, or 24 hours. (C) Apoptosis followed by STAT3 knockdown combined with RAS(ON) inhibition. (i) Representative Annexin V–FITC/PI density plot of MeWo NRAS WT , NRAS Q61R , NRAS Q61K , and NRAS Q61L cells treated for 48 hours with 1 μM RMC-6236, 1 μM RMC-7977, or DMSO. Red gate denotes apoptotic cells (Annexin VL). (ii) Quantification of total apoptotic cells. Data are presented as mean ± SD (n = 3). Statistical significance was assessed using Two-way ANOVA with Sidak’s multiple-comparisons test (*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001). (D) Western blot of MYC, p-STAT3, and cleaved PARP following siSTAT3 combined with 24-hour treatment with 1 μM RMC-6236 or RMC-7977. From (A) to (D), data were confirmed with independent experiments. (E) Receptor Tyrosine Kinase activation following RAS(ON) inhibitor treatment. (i) Representative phospho-RTK array from NRAS Q61R MeWo cells treated with 1 μM RMC-6236 or vehicle for 18 hours. (ii) Quantification of significantly upregulated RTKs. Data are mean ± SD. Statistical significance was determined by Two-way ANOVA with Sidak’s multiple-comparisons test (*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001).
Article Snippet: RTK activation was evaluated using the Proteome ProfilerTM Human Phospho-RTK Array Kit (R&D Systems, Cat. No. ARY001B).
Techniques: Inhibition, Expressing, Western Blot, Derivative Assay, Knockdown, Activation Assay
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