Background and aims As a ferroptosis inducer, sorafenib, a first-line treatment for hepatocellular carcinoma (HCC), has a significant antitumor effect. Nonetheless, HCC patients frequently develop sorafenib resistance. Here, we investigated the impacts of progestagen-associated endometrial protein (PAEP), which controls sorafenib resistance and tumorigenesis in HCC. Furthermore, we investigated the function of PAEP and the underlying molecular mechanisms that cause HCC ferroptosis when sorafenib is applied. Methods Western blot analysis, cell proliferation, colony formation and animal experiments were performed to investigate the function of PAEP in sorafenib resistance and tumorigenesis in HCC. We detected the levels of reactive oxygen species, iron, and malondialdehyde and preformed transmission electron microscopy to investigate the relationship between PAEP and ferroptosis. Co-immunoprecipitation (co-IP) assay was performed to investigate the underlying molecular mechanisms of PAEP that cause HCC ferroptosis. Results PAEP was significantly overexpressed in HCC tissues, and this was associated with a poor clinical prognosis. PAEP silencing dramatically reduced HCC cells’ malignant phenotype. We found that sorafenib-induced ferroptosis was more sensitive to HCC cells with PAEP knockdown. Furthermore, the orthotopic cell line-derived xenograft mouse model results showed that sorafenib sensitivity can be effectively increased in vivo by PAEP knockdown. We determined that transferrin (TF) was a PAEP target using the String database, and we further supported this finding with Co-IP analysis. Additionally, on sorafenib-induced ferroptosis in HCC cells, TF partially reversed the effects of PAEP knockdown. Conclusions Our research indicates that PAEP may be a potential biomarker for predicting sorafenib resistance in HCC and disruption of PAEP expression may be a potential cancer-directed therapeutic option for HCC.

Biliary tract malignant tumours do not have any special symptom or physical sign in early stages.It is easy to be delayed for diagnosis and it is often very serious when the disease was diagnosised.With the development of technology of molecular biology,the biliary tract malignant tumours' diagnosis in molecular biology has been made some progresses,and it is expected to be possible to diagnose and treat the diseases in early stages.