Dissection of Gαs and Hedgehog Signaling Cross-talk Reveals Therapeutic Opportunities to Target Hedgehog-Dependent Tumors.

Abstract

Basal cell carcinoma (BCC), the most common human cancer, is driven by hyperactivation of the Hedgehog pathway mediated by Smoothened (SMO) signaling and Glioma-Associated Oncogene Homolog (GLI) transcription. Gαs and protein kinase A (PKA) negatively regulate Hedgehog signaling, offering a potential alternative BCC development and treatment pathway. In this study, using histology alongside bulk and single-cell RNA sequencing, we found that mouse BCC-like tumors that originate from Gαs pathway inactivation are highly similar to those driven by canonical Hedgehog signaling induced by constitutive SMO activation. Both pathways led to the expansion of basal stem cells in the skin, with tumor cells clustering in two distinct populations with markers for touch dome and isthmus stem cell-like cells. Interestingly, mutations that reduce Gαs and PKA activity were present in human BCC. Tumors from Gαs pathway inactivation were independent of the canonical Hedgehog regulators SMO and GPR161, establishing them as SMO-independent oncogenic Hedgehog signaling models. Finally, activation of the Gαs-coupled adenosine 2B receptor with BAY60-6583 counteracted oncogenic SMO, reducing Hedgehog signaling and tumor growth. Together, these findings offer a potential therapeutic strategy for BCC. Gαs/PKA pathway inactivation drives Hedgehog-dependent basal cell carcinoma and can be counteracted by activation of the Gαs-coupled adenosine 2B receptor to suppress tumor growth, providing a potential treatment for Hedgehog-driven tumors.