paclitaxel + ICG-001, ICG-001 vs. role in TNBC drug resistance and CSC phenotype. CBP/-catenin/FOXM1 provides a molecular target for precision therapy in triple negative breast cancer and could form a rationale for potential clinical trials. = 0.004) . Alterations in p300 were also present in BC, albeit at significantly lower levels (e.g., amplification 0.32 0.11%) (Figure S1). Protein levels of CBP were high in TNBC cell lines (MDA-MB-231 and MDA-MB-468) compared to the non-tumorigenic breast epithelial cell line MCF10a (Figure 1C). Previous studies demonstrated that survivin (BIRC5) is a direct target of CBP/-catenin transcription . Survivin was highly expressed in MDA-MB-231 and MDA-MB-468 cells, compared to MCF10a (Figure 1C). Co-Immunoprecipitation (CoIP) demonstrated that CBP binds to Rabbit polyclonal to Junctophilin-2 -catenin in three TNBC cell lines (MDA-MB-231, MDA-MB-468 and SUM149) under DMSO control conditions, which can be disrupted with 20M ICG-001 (Figure 1D). Treatment with ICG-001 led to the down-regulation of survivin reporter activity (Figure 1E) and protein levels (Figure 1F). ICG-001 specifically inhibits the viability of CBP-dependent MDA-MB-231 cells, but not non-transformed MCF10a cells (Figure 1G). Open in a separate window Figure 1 CBP as a potential target in TNBC. (A) Seven publicly available data sets showed genetic alterations in CBP in breast cancer (cBioPortal). (B) RNA expression levels of CBP in the TCGA BC data set (= 593); left box plot: normal breast tissue compared to BC (2.91-fold BC vs. normal, = 0.015), right box plot TNBC compared to BC other subtypes (1.18-fold TNBC vs. others, = 0.012) (Oncomine database). (C) CBP, survivin and -catenin protein levels in two TNBC cell lines (MDA-MB-231, MDA-MB-468) and non-tumorigenic epithelial breast cell line MCF10a. (D) Co-Immunoprecipitation (CoIP) of CBP/-catenin in three TNBC cell lines (MDA231, MDA468 and SUM149) under DMSO vehicle control conditions and after treatment with 20 M ICG-001 for 24 h (DMSO 6961 2647 vs. ICG-001 1093 1640). The area under the curve (AUC) refers to summary results for MDA-MB-231, MDA-MB-468 TAME hydrochloride and SUM149 for CBP/b-catenin binding under DMSO (red bar) and ICG-001 (blue bar) treatment conditions. (E) Survivin-promoter driven luciferase reporter activity in three TNBC cell lines (MDA-MB-231, MDA-MB-468 and Hs578T) treated for 24 h with 10 M ICG-001 or DMSO vehicle control. (F) Western blot for survivin expression MDA-MB-231 treated for 24 h with 10 M ICG-001 or DMSO vehicle control. (* 0.05, ** 0.01, **** 0.0001). (G) Cell viability of not non-transformed MCF10a cells (top panel) and MDA-MD-231 TNBC cells (bottom panel) treated for up to 72 h with different concentrations of ICG-001. 2.2. FOXM1 is a Downstream Effector of CBP-Signaling in TNBC CBP/-catenin form transcriptionally active complexes via interaction with DNA-binding TFs [25,26]. Differential gene expression analysis of whole transcriptome RNA Seq data of MDA-MB-231 treated for 48 h with either 10 M ICG-001 or DMSO vehicle control revealed that 1339 genes are differentially expressed between treatment and control conditions (DMSO TAME hydrochloride vs. ICG-001 729 genes up-regulated, 610 genes down-regulated, FDR 0.05, |2-fold| change) (Figure 2A). Analysis of this differentially expressed gene-signature using Ingenuity Pathway Analysis (IPA) revealed FOXM1 as a potential upstream-regulator of the gene expression changes observed (Figure 2B). The TCGA BC RNA Seq dataset confirmed that TNBCs are characterized by high TAME hydrochloride expression of FOXM1 target genes compared to other molecular subtypes (Figure S2). Comparison of CBP TAME hydrochloride and FOXM1 RNA expression in the TCGA BC (all subtypes) and TNBC datasets via Oncomine showed that 39.5% (30/76).