Combinations of PRI-724 Wnt/β-Catenin Pathway Inhibitor with Vismodegib, Erlotinib, or HS-173 Synergistically Inhibit Head and Neck Squamous Cancer Cells

Abstract

The Wnt/β-catenin, EGFR, and PI3K pathways frequently undergo upregulation in head and neck squamous carcinoma (HNSCC) cells. Moreover, the Wnt/β-catenin pathway together with Hedgehog (Hh) signaling regulate the activity of cancer stem cells (CSCs). The aim of this study was to investigate the effects of the combinatorial use of the Wnt/β-catenin and Hh pathway inhibitors on viability, cell cycle progression, apoptosis induction, cell migration, and expression of CSC markers in tongue (CAL 27) and hypopharynx (FaDu) cancer cells. Co-inhibition of Wnt signaling with EGFR or PI3K pathways was additionally tested. The cells were treated with selective inhibitors of signaling pathways: Wnt/β-catenin (PRI-724), Hh (vismodegib), EGFR (erlotinib), and PI3K (HS-173). Cell viability was evaluated by the resazurin assay. Cell cycle progression and apoptosis induction were tested by flow cytometric analysis after staining with propidium iodide and Annexin V, respectively. Cell migration was detected by the scratch assay and CSC marker expression by the R-T PCR method. Mixtures of PRI-724 and vismodegib affected cell cycle distribution, greatly reduced cell migration, and downregulated the transcript level of CSC markers, especially POU5F1 encoding OCT4. Combinations of PRI-724 with erlotinib or HS-173 were more potent in inducing apoptosis.

Transcriptional regulation of cancer stem cell: regulatory factors elucidation and cancer treatment strategies

“…For example, GANT61 combined with mTOR inhibition effectively reduces the viability of CSCs and the sphere formation of resistant cell lines in pancreatic cancer [137]. The mixture of Wnt pathway inhibitor PRI-724 and Hh pathway inhibitor vismodegib causes cell cycle arrest and downregulates the expression of OCT4 in CSCs [138]. GSK-3β and MEK inhibitors can promote tumor growth and activate the expression of downstream Wnt signaling factors, and their combined use has been shown to affect CSC maintenance and radiation sensitivity in cervical cancer [139].…”

The Role of Hedgehog Signaling Pathway in Head and Neck Squamous Cell Carcinoma

“…Recently, interesting results were reported by Kleszcz et al, who presented a combined therapy with inhibitors of several signaling pathways in HNSCC [ 190 ]. They analyzed the therapeutic effects caused by selected inhibitors of the following signaling pathways, such as HH (vismodegib), WNT/β-catenin (PRI-724), PI3K (HS-173), and EGFR (erlotinib), separately and in combination on the tongue (CAL 27) and hypopharynx (FaDu) cancer cell lines [ 190 ]. The study showed a better response of the hypopharynx than tongue cell lines to the dual inhibition of WNT and HH signaling [ 190 ].…”

“…They analyzed the therapeutic effects caused by selected inhibitors of the following signaling pathways, such as HH (vismodegib), WNT/β-catenin (PRI-724), PI3K (HS-173), and EGFR (erlotinib), separately and in combination on the tongue (CAL 27) and hypopharynx (FaDu) cancer cell lines [ 190 ]. The study showed a better response of the hypopharynx than tongue cell lines to the dual inhibition of WNT and HH signaling [ 190 ]. A similar effect was observed when simultaneous inhibition with PRI-724 and erlotinib or PRI-724 and the PI3K inhibitor (HS-173) was used [ 190 ].…”

“…The study showed a better response of the hypopharynx than tongue cell lines to the dual inhibition of WNT and HH signaling [ 190 ]. A similar effect was observed when simultaneous inhibition with PRI-724 and erlotinib or PRI-724 and the PI3K inhibitor (HS-173) was used [ 190 ]. Moreover, the authors postulated that simultaneous inhibition of the WNT and HH pathways decreased CAL 27 and FaDu cell migration and had better anti-proliferative than pro-apoptotic effects.…”

“…Moreover, the authors postulated that simultaneous inhibition of the WNT and HH pathways decreased CAL 27 and FaDu cell migration and had better anti-proliferative than pro-apoptotic effects. In contrast, PRI-724 combined with erlotinib or HS-173 significantly increased the apoptosis of cell populations, but its individual usage showed lower apoptotic efficacy [ 190 ]. Currently, it is widely postulated that a multitherapeutic approach with several anticancer drugs may provide a better response than single therapy, even when molecularly targeted [ 191 ].…”