Biology subjects

Andrisani, O.

Publications and source records attributed to Andrisani, O..

3 recordsLinked to original sources

bioRxiv2022

RNA helicase DDX5 mediates adaptive response to multi-kinase inhibitors in liver cancer

ObjectiveTo determine the role of RNA helicase DDX5 in sorafenib/multi-tyrosine kinase inhibitor (mTKI) response. Sorafenib and mTKIs downregulate DDX5 in vitro and preclinical hepatocellular carcinoma (HCC) models. In turn, sorafenib-mediated DDX5 downregulation activates Wnt/{beta}-catenin and non-canonical NF-{kappa}B signaling, resulting in ferroptosis escape and mTKI resistance. Design and ResultsMolecular, pharmacologic and bioinformatic approaches were employed in human HCC cell lines, preclinical HCC models, and HCCs from TCGA. Earlier studies linked sorafenib effectiveness to ferroptosis. Herein we demonstrate sorafenib/mTKIs downregulate DDX5 in vitro and in vivo. To understand the effect of DDX5 downregulation, we compared TCGA-derived HCCs expressing low vs. high DDX5 focusing on ferroptosis-related genes. Glutathione Peroxidase 4 (GPX4), a key ferroptosis regulator, was significantly overexpressed in DDX5LOW HCCs. Importantly, DDX5-knockdown (DDX5KD) HCC cell lines lacked lipid peroxidation by GPX4 inhibition, indicating DDX5 downregulation suppresses ferroptosis. RNAseq of wild type vs. DDX5KD cells untreated or treated with sorafenib, identified a unique set of genes repressed by DDX5 and upregulated by sorafenib. This set significantly overlaps genes from Wnt/{beta}-catenin and non-canonical NF-{kappa}B pathways, including NF-{kappa}B inducing Kinase required for non-canonical NF-{kappa}B activation. Pharmacologic inhibition of these pathways in combination with sorafenib reduced DDX5KD cell viability. Mechanistically, sorafenib-mediated NIK expression induced NRF2 transcription, while DDX5KD extended NRF2 half/life by stabilizing p62/SQSTM1, enhancing GPX4 expression and ferroptosis escape. ConclusionSorafenib/mTKI-mediated DDX5 downregulation results in adaptive mTKI resistance by enhancing NRF2 expression, leading to ferroptosis escape. We propose inhibition of the pathways leading to NRF2 expression will enhance the therapeutic effectiveness of sorafenib/mTKIs. O_LIWhat is already known on this topic - In advanced HCC, mTKIs/sorafenib, offer limited survival benefits due to resistance. Combination of VEGF (bevacizumab) and PD-L1 antibody (atezolizumab) has led to its adoption as first line treatment; however, mTKIs are still widely used in patients with contra-indications to bevacizumab; also, in atezolizumab/bevacizumab failure, mTKIs are the gold standard in second or later-line systemic therapy, emphasizing the importance of delineating the mechanism of mTKI resistance. C_LIO_LIWhat this study adds - We show mTKIs and sorafenib downregulate the RNA helicase DDX5. This downregulation of DDX5 by sorafenib enables activation of Wnt/{beta}-catenin and non-canonical NF-{kappa}B pathways, leading to expression of genes that enable escape from ferroptotic cell death. C_LIO_LIHow this study might affect research, practice or policy The Wnt/{beta}-catenin and non-canonical NF-{kappa}B pathways activated by sorafenib/DDX5 downregulation can serve as druggable targets to enhance the anti-cancer effect of mTKIs by inducing ferroptosis, thereby opening-up new therapeutic directions against mTKI resistance. C_LI

cancer biology↗

bioRxiv2020

RNA helicase DDX5 enables STAT1 mRNA translation and interferon signaling in hepatitis B virus replicating hepatocytes

ObjectiveRNA helicase DDX5 is downregulated during hepatitis B virus (HBV) replication, and poor prognosis HBV-related hepatocellular carcinoma (HCC). The objective of this study is to understand the significance of DDX5 downregulation during HBV infection and poor prognosis HCC, as it pertains to therapy of chronically HBV-infected patients with HCC. IFN- therapy is effective only for a subgroup of HBV-infected patients, for reasons not understood. Herein, we investigated a novel mechanism of STAT1 translational control, involving DDX5-mediated resolution of a G-quadruplex structure, located at the 5UTR of STAT1 mRNA, enabling STAT1 translation. Design and ResultsMolecular, pharmacologic, and biophysical assays were used together with cellular model of HBV replication, HCC cell lines, and HBV-related liver tumors. We observed, the protein level of DDX5 correlated with that of transcription factor STAT1. We show, DDX5 regulates STAT1 mRNA translation by resolving a G-quadruplex (rG4) RNA structure, proximal to the 5 end of STAT1 5UTR. We employed luciferase reporter assays comparing wild type (WT) vs. mutant (MT) rG4 sequence, rG4-stabilizing compounds, CRISPR/Cas9 editing of the rG4 sequence, and circular dichroism determination of rG4 structure. Ribonucleoprotein assays identified direct DDX5 binding to WT but not MT rG4. Importantly, liver cancer cell lines expressing low DDX5 exhibited reduced interferon response, while immunohistochemistry of HBV-related HCCs exhibiting absence of DDX5, also lacked STAT1. ConclusionDDX5 resolves a G-quadruplex structure in 5UTR of STAT1 mRNA, enabling STAT1 translation. DDX5 is a key regulator of the dynamic range of interferon response during innate immunity and adjuvant IFN- therapy.

cancer biology↗

bioRxiv2019

RNA Helicase DDX5 Negatively Regulates Wnt Signaling and Hepatocyte Reprogramming in Hepatitis B Virus-related Hepatocellular Carcinoma

Background and AimsRNA helicase DEAD box protein 5 (DDX5) is downregulated during hepatitis B virus (HBV) replication, and associates with poor prognosis HBV-related hepatocellular carcinoma (HCC). The aim of this study is to determine the mechanism and significance of DDX5 downregulation for HBV-driven HCC.\n\nApproach & ResultsWe used established cellular models of HBV replication, HBV infection, as well as HBV-related liver tumors. HBV replicating DDX5 knockdown hepatocytes were analyzed by RNAseq; differentially expressed genes were validated by qRT-PCR, and bioinformatic analyses of HCCs from The Cancer Genome Atlas. Our results show reduced expression of DDX5 in HCCs of all etiologies is associated with poor survival. In HBV replicating hepatocytes, downregulation of DDX5 is mediated by miR17[~]92 and miR106b[~]25, induced by HBV infection. Increased expression of these miRNAs was quantified in HBV-associated HCCs expressing a hepatic cancer stem cell (hCSC)-like gene signature and reduced DDX5 mRNA, suggesting a role for DDX5 in hCSC formation. Interestingly, DDX5 knockdown in HBV replicating hepatocyte cell lines resulted in hepatosphere formation, sorafenib and cisplatin resistance, Wnt signaling activation and pluripotency gene expression, all characteristics of hCSCs. Moreover, DDX5 knockdown increased viral replication. RNA-seq analyses of HBV-replicating DDX5 knockdown cells, identified enhanced expression of key genes of the Wnt/{beta}-catenin pathway, including Frizzled7 (FZD7) and Matrix Metallopeptidase7 (MMP7), indicative of Wnt signaling activation. Clinically, elevated FZD7 expression correlates with poor patient survival. Importantly, inhibitors to miR17[~]92 and miR106b[~]25 restored DDX5 levels and suppressed both Wnt/{beta}-catenin activation and viral replication.\n\nConclusionDDX5 is a negative regulator of Wnt signaling and hepatocyte reprogramming in HCCs. Restoration of DDX5 levels in HBV-infected patients can exert both antitumor and antiviral effects.

cancer biology↗