Notum leads to potential pro-survival of OSCC through crosstalk between Shh and Wnt/beta-catenin signaling via p-GSK3beta.

Notum, which belongs to the alpha/beta hydrolase family, is a deacylated extracellular protein that regulates the Wnt signaling pathway. Studies have found that Notum participates in the progression of colorectal cancer and hepatocellular carcinoma, but its role in oral squamous cell carcinoma (OSCC) is currently unclear. This study aimed to explore the role of Notum in regulating OSCC and further reveal the underlying mechanisms. Various approaches including bioinformatics analysis, enzyme-linked immunosorbent assay and immunohistochemical staining were used to detect the expression of Notum in OSCC cells and tissues. Cell counting kit-8 assay, clone formation assay, wound healing assay, transwell assay and in-gel zymography assay were explored to evaluate the regulation of Notum in OSCC proliferation and migration. Hoechst 33342/PI assay, cell immunofluorescence, flow cytometry and in vivo tumorigenesis experiment were applied for OSCC apoptosis. Real-time quantitative polymerase chain reaction analysis was performed for mRNA level while western blotting was conducted to detect protein expression. The results showed that Notum was highly expressed in OSCC tissues and cells, and Notum promoted the proliferation and migration of OSCC cells while it inhibited their apoptosis. Furthermore, signaling pathway analysis showed that Notum led to potential pro-survival of OSCC through crosstalk between sonic hedgehog (Shh) and Wnt/beta-catenin signaling via phosphorylation of glycogen synthase kinase-3 beta. These results will help to elucidate the mechanism and also provide new ideas for targeted treatment of OSCC.