Tumor-promoting functions of UHRF1 in retinoblastoma

UHRF1 (ubiquitin-like with PHD and ring finger domains 1) is an epigenetic regulator that is involved in the regulation of DNA and histone methylation and many other cellular events. The UHRF1 is frequently found to be overexpressed in various human cancers including retinoblastoma, and its overexpression has been associated with tumor-promoting effects such as inhibition of apoptosis and high metastatic potential. However, the detailed mechanisms underlying these tumor-promoting functions of UHRF1 in retinoblastoma still remain unclear. In this study, we uncovered that UHRF1 depletion in retinoblastoma cells sensitizes the cells to histone deacetylase (HDAC) inhibitors, augmenting apoptotic cell death. To understand the molecular mechanisms underlying the enhanced sensitivity to HDAC inhibitors in the UHRF1-depleted retinoblastoma cells, we performed the gene expression profiling in UHRF1-knockdown Y79 cells in comparison with control-knockdown cells by RNA-sequencing to identify differentially expressed genes. Our RNA-seq results revealed that UHRF1 depletion downregulates redox-responsive genes such as GSTA4 and TXN2, leading to increased intracellular oxidative stress and higher susceptibility to HDAC inhibitor treatment. Gene expression profiling of control-knockdown (YT) and UHRF1-knockdown (YS) Y79 retinoblastoma cell line by RNA-seq; Identification of differentially expressed genes between control and UHRF-knockdown Y79 cells using two independent biological replicates