Bioinformatic identification of CIP4 as an effector of the Hippo pathway. Impact on hepatocarcinoma progression.

TONUCCI FM; ALMADA E; PARIANI A; HIDALGO F; FAVRE C; LAROCCA MC

Congreso; Reunion cientifica anual conjunta de SAIC, SAI Y SAFIS; 2018

The CDC42 interacting protein 4 (CIP4) is CDC42 effector involved in the regulation of actin dynamics and membrane deformation, which participates in the development of metastatic properties in breast and lung cancer cells. The Hippo pathway is a signaling pathway conserved from Drosophila, which regulates organogenesis and epithelial tissue homeostasis. The relevance of this pathway in cancer progression has received a surge of attention in the last decade. The aim of this study was to evaluate the impact of CIP4 overexpression on hepatocarcinoma prognosis and to identify putative transcriptional regulators for this protein in hepatocarcinoma cells. Bioinformatic analysis of CIP4 mRNA expression on Cancer Atlas Hepatocarcinoma dataset (372 patients) showed a significant difference between patients with high CIP4 expression (first quartile, CIP4OE) and the others on overall survival* (CIP4OE: 37.29 months; Others: 60.84 months), disease free survival* (CIP4OE: 13.0 months; others: 23.03 months) and others prognosis markers such as nodule invasion and distant metastasis. Analysis of genetic network interactions using ARACNE algorithm showed that TEAD transcription factors, key members of Hippo signaling pathway, are possible regulators of CIP4 expression. Concomitantly, CHIPsec data in hepatocarcinoma HepG2 cells showed that TEAD4 binds to a region near CIP4 transcription starting site. That sequence contains a predicted JASPAR binding site. GSEA enrichment analysis showed a significant difference in Hippo pathway molecular signature in patients with high CIP4 expression. In situ assessment of CIP4 protein levels in Hepa1-6, MCF7, MDA-MB-231 and A549 cells treated with TEAD4 inhibitor Verteporfin showed that CIP4 expression was significantly reduced by this treatment, indicating that CIP4 expression was indeed regulated by the Hippo pathway. These findings showed evidence, for the first time, of CIP4 regulation by TEAD transcription factors and supports the idea that CIP4 could link the Hippo pathway to the cytoskeleton remodeling associated to cancer invasion and metastasis.