Targeting the Wnt/β-catenin pathway in primary ovarian cancer with the porcupine inhibitor WNT974

Abstract

Preclinical studies in ovarian cancer have demonstrated upregulation of the Wnt/β-catenin pathway promoting tumor proliferation and chemoresistance. Our objective was to evaluate the effect of the Wnt/β-catenin pathway inhibitor, WNT974, in primary ovarian cancer ascites cells. Ascites cells from patients with papillary serous ovarian cancer were isolated and treated with 1 μM WNT974 ± 100 μM carboplatin. Viability was evaluated with the ATPlite assay. The IC 50 was calculated using a dose-response analysis. Immunohistochemistry (IHC) was performed on ascites cells and tumor. Expression of R-spondin 2 (RSPO2), RSPO3, PORCN, WLS, AXIN2, and three previously characterized RSPO fusion transcripts were assessed using Taqman assays. Sixty ascites samples were analyzed for response to WNT974. The ascites samples that showed a decrease in ATP concentration after treatment demonstrated no difference from the untreated cells in percent viability with trypan blue staining. Flow cytometry demonstrated fewer cells in the G2 phase and more in the G1 and S phases after treatment with WNT974. Combination therapy with WNT974 and carboplatin resulted in a higher percentage of samples that showed ≥ 30% reduction in ATP concentration than either single drug treatment. IHC analysis of Wnt pathway proteins suggests cell cycle arrest rather than cytotoxicity after WNT974 treatment. QPCR indicated that RSPO fusions are not prevalent in ovarian cancer tissues or ascites. However, higher PORCN expression correlated to sensitivity to WNT974 (P = 0.0073). In conclusion, WNT974 produces cytostatic effects in patient ascites cells with primary ovarian cancer through inhibition of the Wnt/β-catenin pathway. The combination of WNT974 and carboplatin induces cytotoxicity plus cell cycle arrest in a higher percentage of ascites samples than with single drug treatment. RSPO fusions do not contribute to WNT974 sensitivity; however, higher PORCN expression indicates increased WNT974 sensitivity.

B7-H3-targeted 212Pb radioimmunotherapy of ovarian cancer in preclinical models

“…In agreement with previous studies using alternative cancer models, the findings discussed here demonstrate the in vitro and in vivo benefits of targeted relative to non-targeted α-particle RIT in ovarian cancer models. Future work with 212 Pb-376.96 will be required to determine if alternative timing of RIT administration after cancer cell implantation, additional RIT doses, or other combinations of RIT with chemotherapy or inhibitors of the Wnt/β-catenin signaling pathway [50, 51] will effectively eliminate disease in preclinical models of ovarian cancer.…”

Blocking Wnt Secretion Reduces Growth of Hepatocellular Carcinoma Cell Lines Mostly Independent of β-Catenin Signaling

“…Their overall well-performed study depended on a thorough analysis of the HCT116 cell line and to a lesser extent on other lines such as DLD1. Importantly, the β-catenin mutant HCT116 cell line is nowadays known to carry an inactivating mutation in the transmembrane E3 ubiquitin ligase RNF43, which strongly sensitizes these cells to exposure by Wnt ligands (see discussion below) [28], [47], [48], [49]. As such, their study may have unknowingly overstated the importance of Wnt ligand signaling for CRC growth in general, warranting a more extensive analysis in a larger cohort of CRC samples and cell lines.…”

“…Cancers that are considered to be especially responsive to these treatments are the ones carrying somatic mutations resulting in a persistent presence of Wnt receptors at the cell surface [28], [48]. In normal cells, the Wnt/Frizzled receptors are continuously endocytosed and degraded following ubiquitination by RNF43 or its close homolog ZNRF3.…”

Wnt/beta-catenin pathway: modulating anticancer immune response

“…Addition of palmitoyl groups to WNT proteins is catalyzed by PORCN, a biochemical process known as palmitoylation or S-acylation in the endoplasmic reticulum, which enhances WNT secretion into the cytoplasm [57]. WNT974 , a PORCN inhibitor, produced cytostatic effects in ovarian cancer cells in vitro [58] and decreased tumor growth and metastatic spread in head and neck squamous cell carcinoma models in vivo [59]. A phase I/II trial evaluating WNT974 in combination with LGX818 , a specific BRAF inhibitor, and cetuximab in patients with metastatic colorectal cancer bearing WNT and BRAF mutations is ongoing (NCT02278133).…”