Functional and genomic analyses reveal therapeutic potential of targeting β-catenin/CBP activity in head and neck cancer

Abstract

BackgroundHead and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy characterized by tumor heterogeneity, locoregional metastases, and resistance to existing treatments. Although a number of genomic and molecular alterations associated with HNSCC have been identified, they have had limited impact on the clinical management of this disease. To date, few targeted therapies are available for HNSCC, and only a small fraction of patients have benefited from these treatments. A frequent feature of HNSCC is the inappropriate activation of β-catenin that has been implicated in cell survival and in the maintenance and expansion of stem cell-like populations, thought to be the underlying cause of tumor recurrence and resistance to treatment. However, the therapeutic value of targeting β-catenin activity in HNSCC has not been explored.MethodsWe utilized a combination of computational and experimental profiling approaches to examine the effects of blocking the interaction between β-catenin and cAMP-responsive element binding (CREB)-binding protein (CBP) using the small molecule inhibitor ICG-001. We generated and annotated in vitro treatment gene expression signatures of HNSCC cells, derived from human oral squamous cell carcinomas (OSCCs), using microarrays. We validated the anti-tumorigenic activity of ICG-001 in vivo using SCC-derived tumor xenografts in murine models, as well as embryonic zebrafish-based screens of sorted stem cell-like subpopulations. Additionally, ICG-001-inhibition signatures were overlaid with RNA-sequencing data from The Cancer Genome Atlas (TCGA) for human OSCCs to evaluate its association with tumor progression and prognosis.ResultsICG-001 inhibited HNSCC cell proliferation and tumor growth in cellular and murine models, respectively, while promoting intercellular adhesion and loss of invasive phenotypes. Furthermore, ICG-001 preferentially targeted the ability of subpopulations of stem-like cells to establish metastatic tumors in zebrafish. Significantly, interrogation of the ICG-001 inhibition-associated gene expression signature in the TCGA OSCC human cohort indicated that the targeted β-catenin/CBP transcriptional activity tracked with tumor status, advanced tumor grade, and poor overall patient survival.ConclusionsCollectively, our results identify β-catenin/CBP interaction as a novel target for anti-HNSCC therapy and provide evidence that derivatives of ICG-001 with enhanced inhibitory activity may serve as an effective strategy to interfere with aggressive features of HNSCC.Electronic supplementary materialThe online version of this article (10.1186/s13073-018-0569-7) contains supplementary material, which is available to authorized users.

Inhibition of CBP/β-catenin and porcupine attenuates Wnt signaling and induces apoptosis in head and neck carcinoma cells

“…Various mechanisms may contribute to activation of Wnt signaling in HNSCC, thus, potentially both upstream and downstream proteins may serve as suitable targets for downregulation of this cascade. In order to assess pathway inhibition, expression levels of Axin2, MMP7, BIRC5 as well as c-MYC and CCND1, were used as pharmacodynamic readouts, similar to other recent studies [24,[32][33][34]. Interestingly, cell membrane-bound Porcupine and nuclear CBP emerged as the best targets for the effective down-regulation of Wntdependent gene expression in the HNSCC cells tested.…”

“…PRI-724 is a second generation antagonist of CBP/βcatenin interaction, which has already entered clinical trials [33]. It is a more potent enantiomer of ICG-001, which has been shown to reduce the growth of head and neck cancers in preclinical experiments [34,36,37]. In our study, PRI-724 reduced the level of expression of β-catenindependent genes, but it had a weaker effect on the production of TCF/LEF reporter-based luciferase than IWP-2.…”

The Significance of the Dysregulation of Canonical Wnt Signaling in Head and Neck Squamous Cell Carcinomas

“…Moreover, its inhibition with ICG-001 led to significant anti-cancer effects-it reduced the growth of oral tumors and inhibited metastasis in vivo. Moreover, detailed analyses have shown that this compound selectively targeted cancer stem-like cell subpopulations [130,131]. Canonical Wnt signaling was shown to be necessary for the induction of pluripotency by the creation of permissive chromatin in stemness gene promoters.…”

“…reduced stemness [102] decreased cell invasion [106] cell cycle arrest, reduced cell migration, induction of apoptosis [51,107] decreased cisplatin resistance [102] increased radiosensitivity [135] Porcupine IWP-2 inhibitor inhibition of UCA1dependent Wnt activation reduced cell proliferation and migration [84] LGK974 inhibitor reduced Wnt target gene expression reduced tumor growth [125] C59 inhibitor reduced secretion of WNT-3A, reduced CCND1 and BIRC5 expression impaired HPV-driven transformation [126] CBP ICG-001 inhibitor altered gene expression cell cycle arrest, induction of apoptosis, reduced stemness, tumor growth and metastasis [130,131] PI3K pathway emodin inhibition of PI3K/Akt/ β-catenin pathway reduced cell invasiveness [111] pyrithione zinc reduced expression of CCND1 and c-MYC reduced cell proliferation and invasion, apoptosis [119] CUL4B knockdown reduced expression of CCND1, c-MYC, MMP-7 reduced cell growth, migration and invasion [113] Funding: This work was funded by the Polish National Science Centre, grant number 2014/13/D/NZ7/00300.…”

<p>Self-Renewal Signalling Pathway Inhibitors: Perspectives on Therapeutic Approaches for Cancer Stem Cells</p>

“…32 Moreover, ICG-001 effectively suppressed tumour metastasis of aggressive subpopulations of oral squamous cell carcinoma stem-like cells in zebrafish embryos. 33 By disrupting Wnt signalling, ICG-001 also exerts potent effects against leukaemia stem cells. 34 Using clinical databases and patient tumour samples, dual inhibition of Wnt and YAP using ICG-001 and simvastatin, respectively, powerfully suppressed CSC populations in triple negative breast cancer (TNBC).…”