WNT ligands control initiation and progression of human papilloma-virus-driven squamous cell carcinoma

Human papilloma virus (HPV)-driven cutaneous squamous cell carcinoma (cSCC) is the most common cancer in immunosuppressed patients. Despite indications suggesting that HPV promotes genomic instability during cSCC development, the molecular pathways underpinning HPV-driven cSCC development remain unknown. We compared the transcriptome of HPV-driven mouse cSCC with normal skin and observed higher amounts of transcripts for Porcupine and WNT ligands in cSCC, suggesting a role for WNT-signaling in cSCC progression. We confirmed increased Porcupine expression in human cSCC samples. Blocking the secretion of WNT-ligands by the Porcupine inhibitor LGK974 significantly diminished initiation and progression of HPV-driven cSCC. Administration of LGK974 to mice with established cSCC resulted in differentiation of cancer cells and significant reduction of the cancer stem cell compartment. Thus, WNT/b-catenin signaling is essential for HPV-driven cSCC initiation and progression as well as for maintaining the cancer stem cell niche. Interference with WNT-secretion may thus represent a promising approach for therapeutic intervention.