A Novel Role for the Tumor Suppressor Gene ITF2 in Tumorigenesis and Chemotherapy Response

Abstract

Despite often leading to platinum resistance, platinum-based chemotherapy continues to be the standard treatment for many epithelial tumors. In this study we analyzed and validated the cytogenetic alterations that arise after treatment in four lung and ovarian paired cisplatin-sensitive/resistant cell lines by 1-million microarray-based comparative genomic hybridization (array-CGH) and qRT-PCR methodologies. RNA-sequencing, functional transfection assays, and gene-pathway activity analysis were used to identify genes with a potential role in the development of this malignancy. The results were further explored in 55 lung and ovarian primary tumors and control samples, and in two extensive in silico databases. Long-term cell exposure to platinum induces the frequent deletion of <i>ITF2</i> gene. Its expression re-sensitized tumor cells to platinum and recovered the levels of Wnt/β-catenin transcriptional activity. <i>ITF2</i> expression was also frequently downregulated in epithelial tumors, predicting a worse overall survival. We also identified an inverse correlation between <i>ITF2</i> and <i>HOXD9</i> expression, revealing that Non-small cell lung cancer (NSCLC) patients with lower expression of <i>HOXD9</i> had a better overall survival rate. We defined the implication of <i>ITF2</i> as a molecular mechanism behind the development of cisplatin resistance probably through the activation of the Wnt-signaling pathway. This data highlights the possible role of <i>ITF2</i> and <i>HOXD9</i> as novel therapeutic targets for platinum resistant tumors.