FOXM1c is the predominant FOXM1 isoform expressed in cholangiocarcinoma that associated with metastatic potential and poor prognosis of patients

Abstract

Forkhead box M1 (FOXM1) is a transcriptional factor which plays an important role in oncogenesis. Four FOXM1 isoforms, FOXM1a, FOXM1b, FOXM1c and FOXM1d, are known so far. Different FOXM1 isoforms influence progression of cancer in different cancer types. In this study, the FOXM1c isoform and its impact in cholangiocarcinoma (CCA) was identified. FOXM1c was found to be the predominant isoform in patient-CCA tissues and cell lines. Detection of FOXM1c expression in CCA tissues reflected the worse prognosis of the patients, namely the advanced stage and shorter survival. Suppression of FOXM1 expression using siRNA considerably reduced migration and invasion abilities of CCA cell lines. RNA sequencing analysis revealed claudin-1 as a target of FOXM1. FOXM1 exhibited a negative correlation with claudin-1 expression which was demonstrated in patient CCA tissues and cell lines. FOXM1 may be a potential target for therapeutic treatment of the metastatic CCA.

FOXM1a Isoform of Oncogene FOXM1 Is a Tumor Suppressor Suppressed by hnRNP C in Oral Squamous Cell Carcinoma

“…FOXM1 total expression was dramatically upregulated in pancreatic cancer, however, FOXM1a expression did not increase significantly [ 31 ]. Klinhom-on et al showed that normal adjacent tissues of cholangiocarcinoma only expressed the FOXM1a isoform, whereas the FOXM1c and FOXM1b isoforms were expressed only in tumor tissues of cholangiocarcinoma [ 32 ].…”