FOXM1: A Multifunctional Oncoprotein and Emerging Therapeutic Target in Ovarian Cancer

SIMPLE SUMMARY: Ovarian cancer is a lethal disease in women with a 10-year survival rate of <40% worldwide. A key molecular alteration in ovarian cancer is the aberrant overexpression and activation of the transcription factor forkhead box M1 (FOXM1). FOXM1 regulates the expression of a multitude of genes that promote cancer, including those that increase the growth, survival, and metastatic spread of cancer cells. Importantly, FOXM1 overexpression is a robust biomarker for poor prognosis in pan-cancer and ovarian cancer. In this review, we first discuss the molecular mechanisms controlling FOXM1 expression and activity, with a specific emphasis on ovarian cancer. We then discuss the evidence for and the manner by which FOXM1 expression promotes aggressive cancer biology. Finally, we discuss the clinical utility of FOXM1, including its potential as a cancer biomarker and as a therapeutic target in ovarian cancer. ABSTRACT: Forkhead box M1 (FOXM1) is a member of the conserved forkhead box (FOX) transcription factor family. Over the last two decades, FOXM1 has emerged as a multifunctional oncoprotein and a robust biomarker of poor prognosis in many human malignancies. In this review article, we address the current knowledge regarding the mechanisms of regulation and oncogenic functions of FOXM1, particularly in the context of ovarian cancer. FOXM1 and its associated oncogenic transcriptional signature are enriched in >85% of ovarian cancer cases and FOXM1 expression and activity can be enhanced by a plethora of genomic, transcriptional, post-transcriptional, and post-translational mechanisms. As a master transcriptional regulator, FOXM1 promotes critical oncogenic phenotypes in ovarian cancer, including: (1) cell proliferation, (2) invasion and metastasis, (3) chemotherapy resistance, (4) cancer stem cell (CSC) properties, (5) genomic instability, and (6) altered cellular metabolism. We additionally discuss the evidence for FOXM1 as a cancer biomarker, describe the rationale for FOXM1 as a cancer therapeutic target, and provide an overview of therapeutic strategies used to target FOXM1 for cancer treatment.