Figure 2 from Targeting the PREX2/RAC1/PI3Kβ Signaling Axis Confers Sensitivity to Clinically Relevant Therapeutic Approaches in Melanoma
Authors: Ford Catriona A. , Koludrovic Dana , Centeno Patricia P. , Foth Mona , Tsonou Elpida , Vlahov Nikola , Sphyris Nathalie , Gilroy Kathryn , Bull Courtney , Nixon Colin , Serrels Bryan , Munro Alison F. , Dawson John C. , Carragher Neil O. , Pavet Valeria , Hornigold David C. , Dunne Philip D. , Downward Julian , Welch Heidi C.E. , Barry Simon T. , Sansom Owen J. , Campbell Andrew D. 
Published: February 2025

<p>Functional loss of PREX2 function sensitizes to MAPK inhibition <i>in vitro</i> and <i>in vivo</i>. <b>A,</b> Left, Kaplan–Meier overall survival of mice with the indicated genotypes and treatments. BRAF PTEN + vehicle (<i>n</i> = 8; median survival, 12.5 days) vs. BRAF PTEN + AZD6244 (<i>n</i> = 8; median survival, 74.5 days), <i>P</i> = 0.0096; BRAF PTEN PREX2 + vehicle, (<i>n</i> = 7; median survival, 13 days) vs. BRAF PTEN PREX2 + AZD6244 (<i>n</i> = 8; median survival, 108.5 days), <i>P</i> = 0.00005; BRAF PTEN + AZD6244 (<i>n</i> = 8; median survival, 74.5 days) vs. BRAF PTEN PREX2 + AZD6244 (<i>n</i> = 8; median survival, 108.5 days), <i>P</i> = 0.0021 log-rank (Mantel–Cox) test. Middle, longitudinal growth of individual tumors from vehicle-treated (<i>n</i> = 8) vs. AZD6244-treated (<i>n</i> = 7) BRAF PTEN cohorts and vehicle-treated (<i>n</i> = 7) vs. AZD6244-treated (<i>n</i> = 8) BRAF PTEN PREX2 cohorts. Right, relative change in tumor volume in mice with the indicated genotypes over the first 7 days of indicated treatment. BRAF PTEN + vehicle (<i>n</i> = 8), BRAF PTEN + AZD6244 (<i>n</i> = 7), BRAF PTEN PREX2 + vehicle (<i>n</i> = 7), BRAF PTEN PREX2 + AZD6244 (<i>n</i> = 8). <i>P</i> values were calculated by one-way ANOVA corrected for multiple comparisons (Tukey). <b>B,</b> Left, Kaplan–Meier overall survival of mice with the indicated genotypes and treatments. BRAF P53 + vehicle (<i>n</i> = 7; median survival, 14 days) vs. BRAF P53 + AZD6244 (<i>n</i> = 9; median survival, 26 days), <i>P</i> = 0.0204; BRAF P53 PREX2 + vehicle (<i>n</i> = 5; median survival, 14 days) vs. BRAF P53 PREX2 + AZD6244 (<i>n</i> = 8; median survival, 39 days), <i>P</i> = 0.0010; BRAF P53 + AZD6244 (<i>n</i> = 8; median survival, 14.5 days) vs. BRAF P53 PREX2 + AZD6244 (<i>n</i> = 10; median survival, 35 days), <i>P</i> = 0.0034. <i>P</i> values calculated using the log-rank (Mantel–Cox) test. Middle, longitudinal growth of individual tumors from vehicle-treated (<i>n</i> = 5) vs. AZD6244-treated (<i>n</i> = 4) BRAF P53 cohorts and vehicle-treated (<i>n</i> = 7) vs. AZD6244-treated (<i>n</i> = 6) BRAF P53 PREX2 cohorts. Right, relative change in tumor volume over the first 7 days of indicated treatment. BRAF P53 + vehicle (<i>n</i> = 5), BRAF P53 + AZD6244 (<i>n</i> = 4), BRAF P53 PREX2 + vehicle (<i>n</i> = 5), BRAF P53 PREX2 + AZD6244 (<i>n</i> = 6); <i>P</i> values, one-way ANOVA corrected for multiple comparisons (Tukey). <b>C,</b> Left, Kaplan–Meier overall survival of BRAF PTEN and BRAF PTEN PREX2-GD cohorts treated with vehicle or AZD6244. BRAF PTEN + vehicle (<i>n</i> = 8; median survival, 12.5 days) vs. BRAF PTEN + AZD6244 (<i>n</i> = 8; median survival, 74.5 days), <i>P</i> = 0.0096; BRAF PTEN PREX2-GD + vehicle (<i>n</i> = 6; median survival, 11 days) vs. BRAF PTEN PREX2-GD + AZD6244 (<i>n</i> = 8; median survival, 100.5 days), <i>P</i> = 0.0002; BRAF PTEN + AZD6244 (<i>n</i> = 8; median survival, 74.5 days) vs. BRAF PTEN PREX2-GD<sup>+</sup>AZD6244 (<i>n</i> = 8; median survival, 100.5 days), <i>P</i> = 0.0414. <i>P</i> values calculated using the log-rank (Mantel–Cox) test. Middle, longitudinal growth of individual tumors from vehicle-treated (<i>n</i> = 8) vs. AZD6244-treated (<i>n</i> = 7) BRAF PTEN cohorts and vehicle-treated (<i>n</i> = 6) vs. AZD6244-treated (<i>n</i> = 8) BRAF PTEN PREX2-GD cohorts. Right, relative change in tumor volume over the first 7 days of indicated treatment. BRAF PTEN + vehicle (<i>n</i> = 8), BRAF PTEN + AZD6244 (<i>n</i> = 7), BRAF PTEN PREX2-GD + vehicle (<i>n</i> = 5), BRAF PTEN PREX2-GD + AZD6244 (<i>n</i> = 6). <i>P</i> values calculated by one-way ANOVA corrected for multiple comparisons (Tukey). Note that the same BRAF PTEN treatment datasets are represented in <b>A</b> and <b>C</b>. <b>D,</b> Top left, relative confluence of parental WM266.4 cells treated with indicated treatments over the 96-hour period. Representative of a minimum of three independent experiments and three technical replicates. Data, mean ± SEM (confluence relative to starting point). Top right, relative confluence of WM266.4 <i>PREX2</i><sup>KO</sup> pooled lines D2 and A4 treated with indicated treatments over the 96-hour period. Representative of a minimum of four independent experiments and three technical replicates. Data, mean ± SEM (confluence relative to starting point). Bottom left, relative confluence of WM266.4 <i>PREX1</i><sup>KO</sup> pooled lines B4 and A4 treated with indicated treatments over the 96-hour period. Representative of a minimum of three independent experiments and three technical replicates. Data, mean ± SEM (confluence relative to starting point). Bottom right, relative suppression of growth, difference in calculated AUC of DMSO treated vs. AZD6244-treated lines as indicated. Center line, mean. <i>P</i> values calculated by one-way ANOVA corrected for multiple comparisons (Tukey).</p>