Supplementary Tables S1-S15. Table S1. Genes and positions analyzed by amplicon sequencing. Table S2. Genes sequenced by Haloplex Target Enrichment System. Table S3. Antibodies. Table S4. Treatment-induced apoptosis in 10 primary patient-derived sphere cell cultures. Table S5. Genotype of patient-derived colorectal cancer models. Table S6. Exome sequencing of colorectal cancer patient-derived models. Table S7. Genes regulated by NVP-TNKS656 in PDX-P2. Table S8. Genes regulated by NVP-TNKS656 in PDX-P30. Table S9. Genes regulated by NVP-TNKS656 in PDX-P5. Table S10. Intestinal β-catenin/TCF signature in human CRC. Table S11. Genes regulated by β-catenin/FOXO3A signaling in human CRC. Table S12. Molecular profiling of 130 CRC tumors. Table S13. Clinicopathological data of 40 CRC patients treated with PI3K/AKT/mTOR inhibitors and their corresponding baseline tumor samples analyzed for mutations and nuclear β-catenin content. Table S14. Nuclear β-catenin content but not relevant mutations or TNM stage determine response of CRC patients to PI3K/AKT/mTOR inhibitors. Table S15. Multivariate analysis of baseline tumors from patients treated with PI3K/AKT/mTOR inhibitors.
ARTICLE ABSTRACT
Purpose: Oncogenic mutations in the KRAS/PI3K/AKT pathway are one of the most frequent alterations in cancer. Although PI3K or AKT inhibitors show promising results in clinical trials, drug resistance frequently emerges. We previously revealed Wnt/β-catenin signaling hyperactivation as responsible for such resistance in colorectal cancer. Here we investigate Wnt-mediated resistance in patients treated with PI3K or AKT inhibitors in clinical trials and evaluate the efficacy of a new Wnt/tankyrase inhibitor, NVP-TNKS656, to overcome such resistance.Experimental Design: Colorectal cancer patient-derived sphere cultures and mouse tumor xenografts were treated with NVP-TNKS656, in combination with PI3K or AKT inhibitors.We analyzed progression-free survival of patients treated with different PI3K/AKT/mTOR inhibitors in correlation with Wnt/β-catenin pathway activation, oncogenic mutations, clinicopathological traits, and gene expression patterns in 40 colorectal cancer baseline tumors.Results: Combination with NVP-TNKS656 promoted apoptosis in PI3K or AKT inhibitor-resistant cells with high nuclear β-catenin content. High FOXO3A activity conferred sensitivity to NVP-TNKS656 treatment. Thirteen of 40 patients presented high nuclear β-catenin content and progressed earlier upon PI3K/AKT/mTOR inhibition. Nuclear β-catenin levels predicted drug response, whereas clinicopathologic traits, gene expression profiles, or frequent mutations (KRAS, TP53, or PIK3CA) did not.Conclusions: High nuclear β-catenin content independently predicts resistance to PI3K and AKT inhibitors. Combined treatment with a Wnt/tankyrase inhibitor reduces nuclear β-catenin, reverts such resistance, and represses tumor growth. FOXO3A content and activity predicts response to Wnt/β-catenin inhibition and together with β-catenin may be predictive biomarkers of drug response providing a rationale to stratify colorectal cancer patients to be treated with PI3K/AKT/mTOR and Wnt/β-catenin inhibitors. Clin Cancer Res; 22(3); 644–56. ©2015 AACR.
