Biology subjects

Cools, J.

Publications and source records attributed to Cools, J..

5 recordsLinked to original sources

bioRxiv2024

Dual targeting of EZH2 and Histone Deacetylases in hematological malignancies promotes transcriptional and metabolic deregulation leading to ferroptosis

The methyltransferase EZH2 functions as the enzymatic component of the PRC2 complex, which deposits methyl groups on H3K27, leading to chromatin condensation and gene repression. Recent studies have shown that EZH2 can also act as a transcriptional modulator outside of the PRC2 complex and thus, independent of its methyltransferase activity. In this study, we first aimed to investigate the effects of EZH2 enzymatic inhibition versus protein degradation in hematological malignancies. We demonstrate that EZH2 degradation is more effective in blocking cellular proliferation compared to EZH2 enzymatic inhibition, and that EZH2 targeting upregulates the cholesterol biosynthesis pathway. Secondly, combined targeting of EZH2 and HDACs showed synergistic effects in a broader spectrum of hematological malignancies. Mechanistically, combined targeting of EZH2 and HDACs induced increased levels of H3K27 acetylation and strong upregulation of cholesterol biosynthesis. This leads to metabolic stress due to acetyl-CoA depletion, ultimately inducing ferroptotic cell death. Statement of significanceWe show that combined EZH2 and HDAC targeting is a promising therapeutic strategy for a broad spectrum of hematological malignancies. We uncover that EZH2 targeting induces upregulation of cholesterol biosynthesis, which is crucial for the synergistic effect with HDAC inhibition, ultimately leading to ferroptosis induction.

cancer biology↗

bioRxiv2024

Resistance to PSEN1-selective γ-secretase inhibitors in T-cell acute lymphoblastic leukemia

PSEN1-selective gamma-secretase inhibitors (GSI), such as MRK-560, are a potential option for the treatment of T-cell acute lymphoblastic leukemia (T-ALL) with NOTCH1 activating mutations, as these show less toxicity compared to broad-spectrum GSIs. However, an important challenge with targeted therapies for cancer treatment is the rapid development of drug resistance. We therefore investigated if PSEN1 mutations could confer resistance to MRK-560 in T-ALL. We performed a CRISPR-mediated mutagenesis screen in a T-ALL cell line to identify mutations leading to MRK-560 resistance and confirmed these findings in additional cell lines. We identified 3 types of resistance mutations. Mutations at the enzyme-drug interface directly disrupt the interaction of MRK-560 with PSEN1. Mutations at the enzyme-substrate interface cause a shift in relative binding affinities towards drug and/or substrate. The third resistance mechanism involves a mutation at the enzyme-substrate interface that hinders the entrance of MRK-560 to the binding pocket. These findings contribute to the understanding of the PSEN1-selectivity of MRK-560 and can help to design other PSEN1-selective GSIs to overcome resistance in cancer therapy.

cancer biology↗

bioRxiv2023

Microfluidic interfaces for chronic bidirectional access to the brain.

AO_SCPLOWBSTRACTC_SCPLOWHere, we used micron-scale 3D printing to develop microfluidic interfaces which provide chronic fluidic access to the brain of preclinical research models. In mice, we show the delivery interface enables faster, more precise and physiologically less disruptive fluid injection. Moreover, we demonstrate the blood brain barrier (BBB) is intact after chronic implantation of the sampling interface and establish frequent, longitudinal sampling of CSF and biomarkers from the ventricle over long time periods of up to 200 days.

neuroscience↗

bioRxiv2022

A palmitate-rich metastatic niche enables metastasis growth via p65 acetylation

Cancer cells outgrowing in distant organs of metastasis rewire their metabolism to fuel on the available nutrients. While this is often considered an adaptive pressure limiting metastasis formation, some nutrients available at the metastatic site naturally or through changes in organ physiology may inherently promote metastatic growth. We find that the lung, a frequent site of metastasis, is a lipid-rich environment. Moreover, we observe that pathological conditions such as pre-metastatic niche formation and obesity further increase the availability of the fatty acid palmitate in the lung. We find that targeting palmitate processing inhibits spheroid growth in vitro and metastasis formation in lean and obese mice. Mechanistically, we discover that breast cancer cells use palmitate to synthesize acetyl-CoA in a carnitine palmitoyltransferase 1a (CPT1a)-dependent manner. Lysine acetyltransferase 2a (KAT2a), whose expression is promoted by palmitate availability, relies on the available acetyl-CoA to acetylate the NF-{kappa}B subunit p65. This favors nuclear location of p65 and activates a pro-metastatic transcriptional program. Accordingly, deletion of KAT2a phenocopies CPT1a silencing in vitro as well as in vivo and patients with breast cancer show co-expression of both proteins in metastases across palmitate-rich metastatic sites. In conclusion, we find that palmitate-rich environments foster metastasis growth by increasing p65 acetylation resulting in elevated NF-{kappa}B signaling.

cancer biology↗

bioRxiv2022

Aberrant MYCN expression drives oncogenic hijacking of EZH2 as a transcriptional activator in peripheral T cell lymphoma

Peripheral T cell lymphoma (PTCL) is a heterogeneous group of hematological cancers arising from the malignant transformation of mature T cells. In a cohort of 28 PTCL cases, we identified recurrent overexpression of MYCN, a member of the MYC family of oncogenic transcription factors. Approximately half of all PTCL cases was characterized by a MYC expression signature. Inducible expression of MYCN in lymphoid cells in a mouse model caused T cell lymphoma that recapitulated human PTCL with a MYC expression signature. Integration of mouse and human expression data identified EZH2 as a key downstream target of MYCN. Remarkably, EZH2 was found to be an essential co-factor for the transcriptional activation of the MYCN-driven gene expression program, which was independent of methyltransferase activity, but dependent on phosphorylation by CDK1. MYCN-driven T cell lymphoma was sensitive to EZH2 degradation or CDK1 inhibition, which displayed synergy with FDA-approved HDAC inhibitors. Key points- Transcriptomic analysis of PTCL tumors reveals recurrent MYCN overexpression and the presence of a MYC signature in 50% of PTCL cases - EZH2 is a transcriptional cofactor for the MYCN-driven gene expression program, which confers sensitivity to HDAC inhibition

cancer biology↗