E2F2/MUC1 Enhances Cell Stemness of Hepatocellular Carcinoma by Regulating the Notch Signaling Pathway.

Background: The fifth most prevalent cancer in the world, hepatocellular carcinoma (HCC), has a significant fatality rate. A cell surface mucin protein known as MUC1 is widely expressed in different cancer types. Its function in HCC has not, however, been completely investigated. The purpose of this study was to look at biological role of MUC1 in HCC.

Methods: Bioinformatics analysis investigated E2F2 expression in HCC tissues. Immunohistochemistry was used to detect the expression of MUC1 in HCC tissues and paracancerous tissues. qRT-PCR detected E2F2 and MUC1 expression in HCC cells. Dual-luciferase and ChIP assays verified regulatory relationship. CCK-8 assays tested cell viability. Western blot detected stem cell markers and Notch pathway-related proteins. Colony formation assays tested cell proliferation, and sphere formation assays tested the number of cell spheres formed.

Results: MUC1 was significantly upregulated in HCC tissues and cells. Knockdown of MUC1 reduced cell proliferation, expression of stem cell surface markers, the number of cell spheres formed, and Notch signaling pathway-related proteins. Bioinformatics analysis predicted that E2F2 was an upstream transcription factor of MUC1 and was substantially increased in HCC. Dual-luciferase and ChIP assays confirmed the mutual binding relationship between E2F2 and MUC1. Further reversion experiments showed that further silencing of MUC1 reversed the stimulatory effect of overexpressed E2F2 on cell stemness.

Conclusion: In summary, E2F2 could upregulate the expression of MUC1 to regulate Notch signaling pathway and promote stemness of HCC cells. This study revealed a potential regulatory pathway of MUC1-mediated HCC progression, providing new ideas for HCC therapy.