NR5A2 promotes malignancy progression and mediates the effect of cisplatin in cutaneous squamous cell carcinoma

Introduction: Nuclear receptor subfamily five group A member two (NR5A2) plays a key role in the development of many tumor types, while it is uncertain in cutaneous squamous cell carcinoma (cSCC). The aim of this work was to determine the role of NR5A2 in cSCC proliferation, and to determine whether NR5A2 mediates the effect of cisplatin in cSCC. Methods: We performed a systematic study of existing data and conducted a preliminary bioinformatics analysis of NR5A2 expression in cSCC using bioinformatics databases. Immunohistochemical staining was performed on cSCC tissues of seven patients to study NR5A2 expression. NR5A2 expression was examined in human keratin-forming cells (HaCaT) and human cSCC cells (A431, Colo-16, SCL-1, SCL-2, and HSC-5). Stable A431 and SCL-2 cell lines consisting of sh-RNA-NR5A2 were constructed to detect changes in cell proliferation, cell cycle, apoptosis, and to determine the key proteins in the Wnt/beta-catenin pathway. We also investigated changes in the effects of cisplatin on cSCC cells by CCK-8, clone formation assay, and Flow apoptosis assay after NR5A2 knockdown. Results: NR5A2 showed enhanced expression in cSCC tissues than in healthy tissues. Downregulation of NR5A2 in cSCC cells led to the formation of a less malignant phenotype. In contrast, the proliferative capacity of the cSCC cells was enhanced posttreatment with RJW100, an NR5A2 agonist. Additionally, NR5A2 knockdown led to a decrease in the expression level of the proteins in the Wnt/beta-catenin pathway, and this inhibition was reversed by LiCl and recombinant antibody, Wnt3a. Moreover, NR5A2 knockdown resulted in diminished proliferative capacity and increased apoptotic cells after the addition of cisplatin. Conclusion: NR5A2 plays a crucial role in the progression of cSCC, and the Wnt/beta-catenin signaling pathway may be involved in the regulation of NR5A2-mediated cSCC. Knockdown of NR5A2 enhanced both the proliferation inhibiting and apoptosis promoting effects of cisplatin on cSCC.