Abstract
OBJECTIVE: HOX genes are vital for all aspects of mammalian growth and differentiation, and their dysregulated expression is related to ovarian carcinogenesis. The aim of the current study was to establish the prognostic value of HOX dysregulation as well as its role in platinum resistance. The potential to target HOX proteins through the HOX/PBX interaction was also explored in the context of platinum resistance. METHODS: HOX gene expression was determined in ovarian cancer cell lines and primary EOCs, and compared to expression in normal ovarian epithelium and fallopian tube tissue samples. Statistical analysis included one way ANOVA and t-tests, using statistical software R and GraphPad. RESULTS: 30 of the 39 HOX genes were overexpressed in high grade serous EOC compared to normal tissue, most significant being HOXA3, A9, B13 and C10. We detected a molecular HOX gene-signature that predicted poor outcome: overexpression of HOXB4 and HOXB9 was identified in high grade serous cell lines after platinum resistance developed. Targeting the HOX/PBX dimer with the the HXR9 peptide enhanced the cytotoxicity of cisplatin in platinum-resistant ovarian cancer.CONCLUSIONS: HOX genes are highly dysregulated in ovarian cancer. High expression of HOXA13, B6, C13, D1 and D13 is predictive of poor clinical outcome. Targeting the HOX/PBX dimer in platinum–resistant cancer represents a new therapeutic option that should be further developed and tested in clinical trials.