Oncologie cellulaire et moléculaire - Hugues de Thé

Hugues de Thé

Collège de France

Oncologie cellulaire et moléculaire

Année 2024-2025

01 - Stress oxydant et cancers

Hugues de Thé

Collège de France

Oncologie cellulaire et moléculaire

Année 2023-2024

Exploring the World of Protein Post-translational Modifications

Conférence - Tony Hunter : New Insights into Intercellular Crosstalk between Different Cell Populations in Pancreatic Tumors That Can Be Translated into the Clinic

Tony Hunter

Salk Institute, La Jolla, California, USA

Résumé

Pancreatic adenocarcinoma (PDA) is one of the most lethal cancers, primarily due to late diagnosis. PDA is a highly stromal (desmoplastic) and poorly vascularized tumor with a dense extracellular matrix; only ~10% of the cells in the tumor are tumor cells, with the rest of the tumor microenvironment (TME) being comprised of cancer-associated fibroblasts (CAFs, and immune cells, including tumor-associated macrophages (TAMs). To investigate the role of cellular crosstalk between CAFs and tumor cells TME, we set out to identify paracrine factors secreted by activated CAFs in the tumor tissue that act on the tumor cells and can be targeted for therapeutic purposes. Through these studies, we identified the LIF (leukemia inhibitory factor) cytokine, secreted by activated CAFs, that acts on tumor cells to promote survival and maintain stemness, thereby serving as a driver of PDA progression. We have shown that therapeutic targeting of LIF by a neutralizing anti-LIF monoclonal antibody in the G12V KRas/Δp53 KPC mouse model of PDA prolongs survival and increases sensitivity to chemotherapy, implicating LIF signaling as a therapeutic resistance mechanism. We found that LIF levels are elevated in human PDA tissue, and that high LIF levels correlate with disease progression. Serum LIF levels are also elevated in PDA patients and correlate with disease stage, suggesting that LIF could be a useful PDA biomarker, as well as a target for combination PDA therapy. Phase 2 PDA clinical trials with a humanized neutralizing anti-LIF mAb in combination with an anti-PD-L1 mAb are underway.

Recently, we have shown that an HDAC inhibitor in combination with gemcitabine slows the growth of KPC tumors by acting on the CAFs to block desmoplastic signals, and also to reduce expression of LIF. We have also found that LIF contributes to PDA tumor cell resistance to T cell killing, and that mAb neutralization of LIF can enhance the PDA tumor cell killing activity of an engineered T cell line. We are currently exploring the role of oncostatin M (OSM), a cytokine related to LIF that is predominantly made by TAMs, in intercellular crosstalk in PDA and tumor progression, to determine if OSM could be another PDA drug target.

Hugues de Thé

Collège de France - Année 2023-2024

Oncologie cellulaire et moléculaire

Colloque - Explorer la réponse thérapeutique in vivo : Cellular Responses to DNA Damage: From Stalled Forks to Inflammation and Beyond

Intervenant(s)

Philippe Pasero

Institut de Génétique Humaine, CNRS et université de Montpellier

Hugues de Thé

Collège de France - Année 2023-2024

Oncologie cellulaire et moléculaire

Colloque - Explorer la réponse thérapeutique in vivo : GENerating a Break in the Proliferation of Cells after Whole Genome Duplication

Intervenant(s)

Renata Basto

Institut Curie et CNRS

Hugues de Thé

Collège de France - Année 2023-2024

Oncologie cellulaire et moléculaire

Colloque - Explorer la réponse thérapeutique in vivo : Studying Melanoma Evolution One Cell at the Time

Intervenant(s)

Chris Marine

VIB – Leuven Belgique

Hugues de Thé

Collège de France - Année 2023-2024

Oncologie cellulaire et moléculaire

Colloque - Explorer la réponse thérapeutique in vivo : Targeting the DNA Damage Response and Immune Response Interplay: Novel Therapeutic Opportunities

Intervenant(s)

Sophie Postel-Vinay

Institut Gustave Roussy et University College of London

Hugues de Thé

Collège de France - Année 2023-2024

Oncologie cellulaire et moléculaire

Colloque - Explorer la réponse thérapeutique in vivo : How Homologous Recombination (HR)-Deficient Tumors Survive Genomic Instability

Intervenant(s)

Raphaël Ceccaldi

Institut Curie/INSERM

Hugues de Thé

Collège de France - Année 2023-2024

Oncologie cellulaire et moléculaire

Colloque - Explorer la réponse thérapeutique in vivo : Sources of Endogenous DNA Damage and Mutations in Blood – It's Not Just Water and Oxygen

Intervenant(s)

Ketan Patel

Chief Scientist CRUK Director of the Weatherall Institute of Molecular Medicine Oxford University

Hugues de Thé

Collège de France

Oncologie cellulaire et moléculaire

Année 2023-2024

Exploring the World of Protein Post-translational Modifications

Conférence - Tony Hunter : Noncanonical Protein Phosphorylation – Is Histidine Phosphorylation Used as a Reversible Regulatory Mechanism?

Tony Hunter

Salk Institute, La Jolla, California, USA

Résumé

Protein phosphorylation is not restricted to serine, threonine and tyrosine, but can occur on six other amino acids, including histidine. In this lecture, I will discuss what is known about non-canonical protein phosphorylation, focusing on our recent work developing new tools to study histidine phosphorylation in cells and tissues, and their use to investigate the possible roles of histidine phosphorylation in liver cancer, pediatric neuroblastoma, breast cancer and pancreatic cancer.

Histidine phosphorylation of proteins was discovered in 1962, before tyrosine phosphorylation, but much less is known about this PTM because phosphohistidine is chemically very labile and therefore hard to study. We set out to investigate histidine phosphorylation over thirty years ago but were stymied by the lack of key reagents. Because anti-phosphotyrosine antibodies have been so useful in studying tyrosine phosphorylation, we set out to develop anti-pHis antibodies, using chemically stable pHis analogues as antigens. We were successful in generating rabbit monoclonal antibodies selective for the 1-pHis and 3-pHis isoforms of phosphohistidine (pHis), using synthetic peptides containing the 1-Tza and 3-pTza pHis analogues as antigens, respectively. We have carried out structural studies of these mAbs bound to their cognate pTza peptide, which reveal how these mAbs achieve isoform specificity, and we have recently used these structures to engineer a higher affinity anti-3-pHis mAb. We have also exploited these mAbs to survey the pHis phosphoproteome, using mass spectrometry to identify novel sites of histidine phosphorylation and new pHis-containing proteins, which we are exploring.

I will go on to describe how we have utilized these mAbs to investigate roles for histidine phosphorylation in cancer, showing that elevated histidine phosphorylation is a potential driver of hepatocellular carcinoma and pediatric neuroblastoma. Finally, I will discuss ongoing work investigating a role for histidine phosphorylation in triple negative breast cancer and pancreatic cancer, and, in particular, a possible role for histidine phosphorylation in the formation and function of invadopodia structures in neuroblastoma cell invasiveness.

Hugues de Thé

Collège de France

Oncologie cellulaire et moléculaire

Année 2023-2024

Exploring the World of Protein Post-translational Modifications

Conférence - Tony Hunter : Crosstalk between Post-translational Modifications: The Role of Ptm Crosstalk in Protein Degradation

Tony Hunter

Salk Institute, La Jolla, California, USA

Résumé

In this lecture I will discuss the role of PTMs in increasing proteome complexity, why this is important for organisms with genomes of limited protein-coding capacity, and how the combinatorial use of PTMs on a single protein molecule can diversify signal outputs. I will go on to discuss examples of crosstalk between different PTMs in the context of transcriptional regulation mediated by posttranslational modifications of histone tails, and how different PTMs can be used to tag proteins for inducible degradation by the ubiquitin-proteasome system (UPS).

The modification of proteins by ubiquitin and ubiquitin-like proteins, such as SUMO, is second only to phosphorylation in terms of the number of sites modified in the mammalian proteome. I will discuss the versatility of ubiquitylation as a regulatory mechanism, and will review the different classes of ubiquitin ligases, deubiquitylating enzymes and ubiquitin binding domains, and the different members of the ubiquitin-like protein family, such as SUMO.

I will go on to discuss the discovery of RING finger E3 ubiquitin ligases, and, to illustrate their roles in PTM crosstalk, describe our own work on the c-Cbl RING domain protein as a phosphotyrosine-dependent E3 ubiquitin ligase that targets activated receptor tyrosine kinases, and the RNF4 RING domain protein as a SUMO-dependent E3 ubiquitin ligase (STUbL) that is critical in the DNA damage response.

I will end with a description of how we used a budding yeast genetic screen to discover that the RNF4 E3 ligase plays a role in quality control of RNA polymerase III complex assembly, and discuss recent follow up mouse experiments on RNA polymerase III disease mutations that cause a fatal human neurogenerative disease, that could potentially be treated with a sumoylation pathway inhibitor.