Biology subjects

Hanoun, N.

Publications and source records attributed to Hanoun, N..

3 recordsLinked to original sources

bioRxiv2023

The intrinsically disordered region of the E3 ubiquitin ligase TRIP12 induces the formation of chromatin condensates and interferes with DNA damage response.

Chromatin compaction is crucial for the faithful expression and integrity of the genome. Although largely studied, proteins and mechanisms that control the chromatin compaction are not entirely discovered. We previously showed that the nuclear HECT-type E3 ubiquitin ligase Thyroid hormone Receptor Interacting Protein 12 (TRIP12) is tightly associated to chromatin. As TRIP12 is overexpressed in several types of cancers, we explored herein the consequences of a TRIP12 overexpression on chromatin homeostasis. First, we established the TRIP12 proxisome and unveiled its pleiotropic role in chromatin regulation. Second, we demonstrated that TRIP12 overexpression leads to the formation of chromatin condensates enriched in heterochromatin marks via its intrinsically disordered region (IDR). We further discovered that the formation of TRIP12-mediated chromatin condensates is highly dynamic and driven by a mechanism of phase separation. Chromatin condensate formation depends on the TRIP12 concentration, the length of the TRIP12-IDR and relies on electrostatic interactions. We found that the formation of TRIP12 mediated-condensates alters cell cycle progression, genome accessibility, transcription as well as DNA damage response by inhibiting the accumulation of Mediator of DNA Damage Checkpoint 1 (MDC1). Altogether, this study reveals a novel dynamic role for TRIP12 in chromatin compaction independently of its ubiquitin ligase activity with important consequences on cellular homeostasis. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=155 SRC="FIGDIR/small/556486v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@13b3d90org.highwire.dtl.DTLVardef@46b991org.highwire.dtl.DTLVardef@1410bdeorg.highwire.dtl.DTLVardef@1722197_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2022

Preclinical development of non-viral gene therapy for patients with advanced pancreatic cancer

Pancreatic ductal adenocarcinoma remains one of the greatest challenges in oncology for which therapeutic intervention is urgently needed. We demonstrated that the intratumoral gene transfer of somatostatin receptor 2, to combat tumor aggressiveness, or of deoxycytidine kinase and uridylate monophosphate kinase, to sensitize to gemcitabine chemotherapy, has antitumoral potential. Here, we describe the development of CYL-02 non-viral gene-therapy product, that comprises a DNA-plasmid encoding for the three aforementioned genes complexed with PolyEthylEnimine (22 kDa). In this work, we performed preclinical toxicology, biodistribution and therapeutic activity studies of CYL-02 in experimental models of pancreatic cancer. We demonstrated the safety of CYL-02 and defined the maximal tolerated dose in two animal species. CYL-02 co-administrated with gemcitabine did not increase gemcitabine toxicity. Biodistribution studies revealed that CYL-02 is rapidly cleared from blood following intravenous administration, and sequestered in tumors following intratumoral injection. CYL-02 drives the expression of therapeutic genes in cancer cells and strongly sensitizes tumor cells to gemcitabine, with significant inhibition of tumor cells dissemination. This study was instrumental for the later use of CYL-02 in patients with advanced pancreatic cancer, demonstrating that rigorous and thorough preclinical investigations are informative for the clinical transfer of gene therapy against pancreatic cancer. GRAPHICAL ABSTRACT

cancer biology↗

bioRxiv2022

Cytidine deaminase regulates mitochondrial biogenesis in pancreatic cancer cells

Despite tremendous efforts from the scientific community, pancreatic ductal adenocarcinoma (PDAC) is still a deadly disease and will soon become the second cause of death by cancer worldwide1. When surgery is not possible, therapeutic options are few and ineffective2. Patients are most often treated with Folfirinox or gemcitabine chemotherapy, that extends survival in weeks to months. Cytidine deaminase (CDA) catalyzes the irreversible hydrolytic deamination of cytidine and deoxycytidine to uridine and deoxyuridine to fuel RNA and DNA synthesis3. CDA also deaminates and neutralizes deoxycytidine-based therapies, and as such, has been identified as a major contributor of tumor chemoresistance, especially to gemcitabine in PDAC3. We previously identified that CDA is elevated in PDAC tumors at diagnosis and that CDA exerts an unexpected role on DNA replication that can be exploited for therapeutic intervention4. Very recently, CDA was associated with cellular metabolism5. Here, we show that CDA promotes mitochondrial biogenesis and oxidative phosphorylation independently of its deaminase activity. This uncloaks novel therapeutic vulnerabilities in primary cancer cells that overexpress this protein. This study shines a new light on the tumoral potential of CDA in PDAC.

cancer biology↗