Abstract C114: The role of LKB1 and TP53 mutation status in determining sensitivity of non-small cell lung cancer cells to the metabolic inhibitors; metformin, phenformin and 2-DG

Abstract

Abstract Lung cancer is the leading cause of cancer related death worldwide and adenocarcinoma is the most prevalent subtype. LKB1 (STK11) is the second most commonly altered tumour suppressor in adenocarcinoma and is inactivated in 17% of samples (1). LKB1 is a master kinase that phosphorylates up to 13 downstream targets involved in cell polarity and metabolism. It has been reported that LKB1 mutated cells are more sensitive to the metabolic inhibitor phenformin (2). We aimed to further investigate this by testing the toxicity of 3 metabolic inhibitors (metformin, phenformin and 2-DG) in LKB1 mutated (n = 8) and LKB1 WT (n = 4) NSCLC cell lines, as well as in isogenic cell lines with or without WT LKB1 expression (A549-wtLKB1, A549-mutLKB1). There was a wide range of sensitivity [IC50 values: metformin 1.22 mM–34.37 mM; phenformin 0.01–1.39 mM; 2-DG 1.86–15.18 mM] to the inhibitors in the 12 NSCLC cell lines. The IC50values for the LKB1 WT cell lines fell within the range of IC50 values for the LKB1 mutated cell lines. IC50 data was analysed using ANOVA with LKB1, KRAS, and TP53 mutation status as factors and interpreting the partial eta squared (η2) using Cohen's rule of thumb to assess the effect size. By this analysis, LKB1 mutation status had a small effect in determining sensitivity to metformin or phenformin and TP53 mutation status had a large impact, with WT TP53 cells being more sensitive. Cell lineMutation statusIC50 (mM) ± SEMMetforminPhenformin2-DGA549LKB1 (Q37*), KRAS (G12S)1.22 ± 0.120.01 ± 0.0012.14 ± 0.26A427LKB1 ∆, KRAS (G12D)11.56 ± 0.460.65 ± 0.022.45 ± 0.06H1395LKB1 E57fs*, TP53 (C242F)17.99 ± 1.460.54 ± 0.0215.18 ± 1.08H1755LKB1 P281fs*, TP53 (C242F)27.73 ± 1.290.66 ± 0.022.21 ± 0.13H2030LKB1 E317*, TP53 (G262V)34.37 ± 4.181.39 ± 0.298.89 ± 2.10H2126LKB1 ∆, TP53 (E62*)16.33 ± 1.020.80 ± 0.0414.90 ± 1.19H23LKB1 W332*, TP53 (G738C)24.42 ± 3.381.10 ± 0.021.86 ± 0.26H460LKB1 Q37*, KRAS (Q61H)14.15 ± 0.600.35 ± 0.032.52 ± 0.31H1299TP53 deletion16.19 ± 1.090.46 ± 0.036.41 ± 0.47CORL10512.41 ± 0.790.64 ± 0.055.17 ± 0.26Calu6KRAS (Q61K), TP53 (R196*)16.94 ± 1.91.01 ± 0.059.09 ± 0.62NBE120.48 ± 1.160.66 ± 0.014.84 ± 0.32 To further investigate the effect of TP53 status, we transfected isogeneic A549 cells (A549-wtLKB1, A549-mutLKB1) with a vector expressing SV40 large T antigen to inhibit TP53 function. Loss of TP53 function increased resistance in both A549-wtLKB1 (metformin IC50: 5.42 versus 1.92 mM, p < 0.001; phenformin IC50: 0.57 versus 0.02 mM, p <0.001) and A549-mutLKB1 (metformin IC50: 3.99 versus 1.10 mM, p < 0.001; phenformin IC50: 0.53 versus 0.01 mM, p = 0.04) cells. As TP53 is the most commonly mutated tumour suppressor gene in lung adenocarcinoma (46%) (1), our results suggest that TP53 mutation status may be an important factor when considering treatment of NSCLC with metabolic inhibitors. 1. TCGA. Comprehensive molecular profiling of lung adenocarcinoma. Nature. 2014;511(7511):543-50. 2. Shackelford David B, Abt E, Gerken L, Vasquez Debbie S, Seki A, Leblanc M, et al. LKB1 Inactivation Dictates Therapeutic Response of Non-Small Cell Lung Cancer to the Metabolism Drug Phenformin. Cancer Cell. 2013 2/11/;23(2):143-58. Citation Format: Fiona F. Cahill, Sivan Bokobza, Aoife Devery, Neele Drobnitzky, Yanyan Jiang, Luiza Madia Lourenco, Nuramalina Mumin, Anika Weber, Thomas Ashton, Anderson J. Ryan. The role of LKB1 and TP53 mutation status in determining sensitivity of non-small cell lung cancer cells to the metabolic inhibitors; metformin, phenformin and 2-DG. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C114.