Disrupting the Interaction Between HOX and PBX Causes Necrotic and Apoptotic Cell Death in the Renal Cancer Lines CaKi-2 and 769-P

Abstract

The HOX genes are a family of homeodomain containing transcription factors that determine embryonic tissue identity and also have regulatory and oncogenic roles in adult cells. We quantified the expression of HOX genes in normal kidney tissue, primary tumors and derived cell lines, and examined their role in renal cancer cell survival. Quantitative polymerase chain reaction was used to evaluate HOX gene expression in cells and tissues. HOX gene function was disrupted using a peptide that blocks the interaction between HOX proteins and their PBX cofactor. Apoptosis was assessed by annexin/propidium iodide staining and direct measurement of caspase activity. Primary renal tumors and derived cell lines showed abnormal HOX gene expression. Furthermore, blocking HOX activity by targeting the interaction between HOX and its cofactor PBX caused apoptotic and necrotic cell death in the renal cancer cell lines CaKi-2 and 769-P, while sparing normal adult kidney cells. Our findings suggest that the HOX/PBX dimer is a potential therapeutic target in renal cancer.