Inhibition of the Tcf/beta-catenin complex increases apoptosis and impairs adrenocortical tumor cell proliferation and adrenal steroidogenesis

• Published in: Oncotarget 2015-12, Vol.6 (40), p.43016-43032
• Main Authors: Leal, Letícia F, Bueno, Ana Carolina, Gomes, Débora C, Abduch, Rafael, de Castro, Margaret, Antonini, Sonir R
• Format: Article
• Language: English
• Subjects: Adrenal Cortex Neoplasms - pathology; Antineoplastic Agents - pharmacology; Apoptosis - drug effects; beta Catenin - antagonists & inhibitors; Blotting, Western; Cell Line, Tumor; Cell Proliferation - drug effects; Flow Cytometry; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Radioimmunoassay; Real-Time Polymerase Chain Reaction; Research Paper; T Cell Transcription Factor 1 - antagonists & inhibitors; Wnt Signaling Pathway - drug effects
• ISSN: 1949-2553; 1949-2553
• DOI: 10.18632/oncotarget.5513

To date, there is no effective therapy for patients with advanced/metastatic adrenocortical cancer (ACC). The activation of the Wnt/beta-catenin signaling is frequent in ACC and this pathway is a promising therapeutic target. To investigate the effects of the inhibition of the Wnt/beta-catenin in ACC cells. Adrenal (NCI-H295 and Y1) and non-adrenal (HeLa) cell lines were treated with PNU-74654 (5-200 μM) for 24-96 h to assess cell viability (MTS-based assay), apoptosis (Annexin V), expression/localization of beta-catenin (qPCR, immunofluorescence, immunocytochemistry and western blot), expression of beta-catenin target genes (qPCR and western blot), and adrenal steroidogenesis (radioimmunoassay, qPCR and western blot). In NCI-H295 cells, PNU-74654 significantly decreased cell proliferation 96 h after treatment, increased early and late apoptosis, decreased nuclear beta-catenin accumulation, impaired CTNNB1/beta-catenin expression and increased beta-catenin target genes 48 h after treatment. No effects were observed on HeLa cells. In NCI-H295 cells, PNU-74654 decreased cortisol, testosterone and androstenedione secretion 24 and 48 h after treatment. Additionally, in NCI-H295 cells, PNU-74654 decreased SF1 and CYP21A2 mRNA expression as well as the protein levels of STAR and aldosterone synthase 48 h after treatment. In Y1 cells, PNU-74654 impaired corticosterone secretion 24 h after treatment but did not decrease cell viability. Blocking the Tcf/beta-catenin complex inhibits the Wnt/beta-catenin signaling in adrenocortical tumor cells triggering increased apoptosis, decreased cell viability and impairment of adrenal steroidogenesis. These promising findings pave the way for further experiments inhibiting the Wnt/beta-catenin pathway in pre-clinical models of ACC. The inhibition of this pathway may become a promising adjuvant therapy for patients with ACC.