Biology subjects

Wendel, H. G.

Publications and source records attributed to Wendel, H. G..

3 recordsLinked to original sources

bioRxiv2024

5UTR translational inhibition of neuroblastoma dependency factors using the CR-1-31-B rocaglate

Current therapies for neuroblastoma are often ineffective and survivors suffer from severe long-term therapy related side-effects, underscoring the need for identification of novel drugging strategies. We performed an in-depth evaluation of phenotypic and molecular responses following exposure of neuroblastoma cells to the rocaglate CR-1-31-B, scrutinizing its mode-of-action through integrative ribosome footprinting and shotgun proteome profiling. We could show that CR-1-31-B significantly reduces tumor growth in vivo without apparent toxicity. By means of combined ribosome footprinting and transcriptome analysis we uncovered that CR-1-31-B treatment downregulates translation efficiencies of several major neuroblastoma dependencies including MYCN, CCND1 and ALK as well as factors involved in the G2/M checkpoint. Upregulated targets are enriched for oxidative phosphorylation pathway components and DNA repair. At the proteome level, CR-1-31-B imposed downregulation of a FOXM1 driven signature, including the FOXM1 target gene TPX2. We show that neuroblastoma cells are dependent on TPX2 for growth and DNA repair and further demonstrate enhanced CHK1 sensitivity upon TPX2 knockdown. Next, we also observed synergistic effects of CHK1 inhibition with CR-1-31-B. In conclusion, our data support CR-1-31-B as a potent novel therapeutic agent in neuroblastoma, in particular in combination with DNA damage or replication stress inducing agents.

cancer biology↗

bioRxiv2024

eIF4A controls translation of estrogen receptor alpha and is a therapeutic target in advanced breast cancer

The majority of human breast cancers are dependent on hormone-stimulated estrogen receptor alpha (ER) and are sensitive to its inhibition. Treatment resistance arises in most advanced cancers due to genetic alterations that promote ligand independent activation of ER itself or ER target genes. Whereas re-targeting of the ER ligand binding domain (LBD) with newer ER antagonists can work in some cases, these drugs are largely ineffective in many genetic backgrounds including ER fusions that lose the LBD or in cancers that hyperactivate ER targets. By identifying the mechanism of ER translation, we herein present an alternative strategy to target ER and difficult to treat ER variants. We find that ER translation is cap-independent and mTOR inhibitor insensitive, but dependent on 5 UTR elements and sensitive to pharmacologic inhibition of the translation initiation factor eIF4A, an mRNA helicase. EIF4A inhibition rapidly reduces expression of ER and short-lived targets of ER such as cyclin D1 and other components of the cyclin D-CDK complex in breast cancer cells. These effects translate into suppression of growth of a variety of ligand-independent breast cancer models including those driven by ER fusion proteins that lack the ligand binding site. The efficacy of eIF4A inhibition is enhanced when it is combined with fulvestrant--an ER degrader. Concomitant inhibition of ER synthesis and induction of its degradation causes synergistic and durable inhibition of ER expression and tumor growth. The clinical importance of these findings is confirmed by results of an early clinical trial (NCT04092673) of the selective eIF4A inhibitor zotatifin in patients with estrogen receptor positive metastatic breast cancer. Multiple clinical responses have been observed on combination therapy including durable regressions. These data suggest that eIF4A inhibition could be a useful new strategy for treating advanced ER+ breast cancer.

cancer biology↗

bioRxiv2020

The rocaglate CR-31-B (-) inhibits SARS-CoV-2 replication at non-cytotoxic, low nanomolar concentrations in vitro and ex vivo

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a betacoronavirus in the subgenus Sarbecovirus causes a respiratory disease with varying symptoms referred to as coronavirus disease 2019 (COVID-19) and is responsible for a pandemic that started in early 2020. With no vaccines or effective antiviral treatments available, and infection and fatality numbers continuing to increase globally, the quest for novel therapeutic solutions remains an urgent priority. Rocaglates, a class of plant-derived cyclopenta[b]benzofurans, exhibit broad-spectrum antiviral activity against positive- and negative-sense RNA viruses. This compound class inhibits eukaryotic initiation factor 4A (eIF4A)-dependent mRNA translation initiation, resulting in strongly reduced viral RNA translation. The synthetic rocaglate CR-31-B (-) has previously been shown to inhibit the replication of human coronaviruses, such as HCoV-229E and MERS-CoV, as well as Zika-, Lassa-, Crimean Congo hemorrhagic fever virus in primary cells. Here, we assessed the antiviral activity of CR-31-B (-) against SARS-CoV-2 using both in vitro and ex vivo cell culture models. In African green monkey Vero E6 cells, CR-31-B (-) inhibited SARS-CoV-2 replication with an EC50 of ~1.8 nM. In line with this, viral protein accumulation and replication/transcription complex formation were found to be strongly reduced by this compound. In an ex vivo infection system using human airway epithelial cells, CR-31-B (-) was found to cause a massive reduction of SARS-CoV-2 titers by about 4 logs to nearly non-detectable levels. The data reveal a potent anti-SARS-CoV-2 activity by CR-31-B (-), corroborating previous results obtained for other coronaviruses and supporting the idea that rocaglates may be used in first-line antiviral intervention strategies against novel and emerging RNA virus outbreaks.

molecular biology↗