Emergence of cytotoxic resistance in cancer cell populations: single-cell mechanisms and population-level consequences

International audienceWe formulate an individual-based model and a population model of phenotypic evolution, under cytotoxic drugs, in a cancer cell population structured by the expression levels of survival-potential and proliferation-potential. We apply these models to a recently studied experimental system. Our results suggest that mechanisms based on fundamental laws of biology can reversibly push an actively-proliferating, and drug-sensitive, cell population to transition into a weakly-proliferative and drug-tolerant state, which will eventually facilitate the emergence of more potent, proliferating and drug-tolerant cells

The European AntibotABE Framework Program and Its Update: Development of Innovative Botulinum Antibodies

The goal of the AntiBotABE Program was the development of recombinant antibodies that neutralize botulinum neurotoxins (BoNT) A, B and E. These serotypes are lethal and responsible for most human botulinum cases. To improve therapeutic efficacy, the heavy and light chains (HC and LC) of the three BoNT serotypes were targeted to achieve a synergistic effect (oligoclonal antibodies). For antibody isolation, macaques were immunized with the recombinant and non-toxic BoNT/A, B or E, HC or LC, followed by the generation of immune phage-display libraries. Antibodies were selected from these libraries against the holotoxin and further analyzed in in vitro and ex vivo assays. For each library, the best ex vivo neutralizing antibody fragments were germline-humanized and expressed as immunoglobulin G (IgGs). The IgGs were tested in vivo, in a standardized model of protection, and challenged with toxins obtained from collections of Clostridium strains. Protective antibody combinations against BoNT/A and BoNT/B were evidenced and for BoNT/E, the anti-LC antibody alone was found highly protective. The combination of these five antibodies as an oligoclonal antibody cocktail can be clinically and regulatorily developed while their high “humanness” predicts a high tolerance in humans.Peer reviewe

Neutralization of Botulinum Neurotoxin Type E by a Humanized Antibody

Botulinum neurotoxins (BoNTs) cause botulism and are the deadliest naturally-occurring substances known to humans. BoNTs have been classified as one of the category A agents by the Centers for Disease Control and Prevention, indicating their potential use as bioweapons. To counter bio-threat and naturally-occurring botulism cases, well-tolerated antibodies by humans that neutralize BoNTs are relevant. In our previous work, we showed the neutralizing potential of macaque (Macaca fascicularis)-derived scFv-Fc (scFv-Fc ELC18) by in vitro endopeptidase immunoassay and ex vivo mouse phrenic nerve-hemidiaphragm assay by targeting the light chain of the botulinum neurotoxin type E (BoNT/E). In the present study, we germline-humanized scFv-Fc ELC18 into a full IgG hu8ELC18 to increase its immunotolerance by humans. We demonstrated the protection and prophylaxis capacity of hu8ELC18 against BoNT/E in a mouse model. A concentration of 2.5 ng/mouse of hu8ELC18 protected against 5 mouse lethal dose (MLD) in a mouse protection assay and complete neutralization of 1 LD50 of pure BoNT/E toxin was achieved with 8 ng of hu8ELC18 in mouse paralysis assay. Furthermore, hu8ELC18 protected mice from 5 MLD if injected up to 14 days prior to intraperitoneal BoNT/E administration. This newly-developed humanized IgG is expected to have high tolerance in humans.Peer reviewe

FONCTIONS ET REGULATIONS DE L'ADN TOPOISOMERASE II HUMAINE AU COURS DES PHASES PRECOCES DE LA MITOSE

LA CELLULE, POUR ASSURER SA SURVIE, A MIS EN PLACE DIVERS POINTS DE CONTROLE NECESSAIRES A LA BONNE ORGANISATION SPATIALE ET TEMPORELLE DES DIFFERENTES ETAPES DU CYCLE CELLULAIRE. CETTE REGULATION LUI PERMET D'ASSURER LA FIDELITE D'EVENEMENTS CRITIQUES TELS QUE LA REPLICATION DE L'ADN OU LA SEGREGATION DES CHROMOSOMES. LA MISE EN PLACE DE LA MITOSE SE CARACTERISE PAR LA CONDENSATION DES CHROMOSOMES, LA FORMATION DU KINETOCHORE ET LA SEPARATION DES CENTROSOMES. LA TOPOISOMERASE II EST IMPLIQUEE DANS LA CONDENSATION DES CHROMOSOMES ET LA FORMATION DU KINETOCHORE, CES EVENEMENTS ETANT TOUS DEUX REVERSIBLES. L'ENTAME DE LA MITOSE COINCIDE AVEC LA TRANSLOCATION NUCLEAIRE ET L'ACTIVATION DE KINASES MITOTIQUES MAJEURES, TELLES QUE LA KINASE CDC2 ET LA FAMILLE DES KINASES MPM-2. LA TOPOISOMERASE II EST PHOSPHORYLEE PAR LA KINASE CDC2 ET CONSTITUE LA CIBLE MAJEURE ASSOCIEE AUX CHROMOSOMES DE L'ANTICORPS MPM-2. AU COURS DE MON DOCTORAT, JE ME SUIS ATTACHE A MIEUX CARACTERISER LA REGULATION, AU COURS DES PHASES PRECOCES DE LA MITOSE, DE LA TOPOISOMERASE II. CE TRAVAIL AURA PERMIS DE MONTRER UNE INTERACTION DIRECTE ENTRE LA KINASE CDC2 ET LA TOPOISOMERASE II, INTERACTION RESPONSABLE DU CIBLAGE DE L'ACTIVITE CDC2 SUR LES CHROMOSOMES, DE LA STIMULATION DE L'ACTIVITE CATALYTIQUE DE LA TOPOISOMERASE II ET D'UN REMODELAGE SIGNIFICATIF DE LA CHROMATINE. CE TRAVAIL AURA PERMIS, AUSSI, DE MONTRER QUE LA PHOSPHORYLATION PAR LA PROTEINE KINASE CK2 DE LA TOPOISOMERASE II HUMAINE SUR LE RESIDU 1469 INDUIT LA FORMATION DE L'EPITOPE MPM-2. ENFIN, CE TRAVAIL AURA PERMIS DE MIEUX CARACTERISER LES PROPRIETES AUTO-ASSOCIATIVES DE LA TOPOISOMERASE II INTERVENANT LORS DE LA CONDENSATION DES CHROMOSOMES. L'ENSEMBLE DE CES DONNEES APPORTE UN ECLAIRAGE NOUVEAU SUR LES FONCTIONS ET REGULATIONS DE LA TOPOISOMERASE II AU COURS DES PHASES PRECOCES DE LA MITOSE. IL SEMBLE, EN EFFET, QUE SON IMPLICATION PASSE EN GRANDE PARTIE PAR DES ASSOCIATIONS PROTEINE-PROTEINE CAPABLES DE MODULER SES PROPRIETES BIOLOGIQUES ET D'ORIENTER DIVERSES ACTIVITES VERS DES COMPARTIMENTS NUCLEOPLASMIQUES BIEN DETERMINES.PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Intramolecular Aryne-Furan Cycloadditions for the Synthesis of Anticancer Naphthalimides

International audienceAn intramolecular aryne Diels-Alder reaction with a furan moiety was applied to the synthesis of dihydrobenzo[ de]isochromenes as intermediates toward naphthalimides. After oxidation, this method offers an efficient approach for the synthesis of substituted naphthalimides, which showed potent cytotoxic activity against HT-29 human cancer cell line

Colorectal Cancer and Immunity: From the Wet Lab to Individuals

International audienceImmunotherapy is a very promising field of research and application for treating cancers, in particular for those that are resistant to chemotherapeutics. Immunotherapy aims at enhancing immune cell activation to increase tumor cells recognition and killing. However, some specific cancer types, such as colorectal cancer (CRC), are less responsive than others to the current immunotherapies. Intrinsic resistance can be mediated by the development of an immuno-suppressive environment in CRC. The mutational status of cancer cells also plays a role in this process. CRC can indeed be distinguished in two main subtypes. Microsatellite instable (MSI) tumors show a hyper-mutable phenotype caused by the deficiency of the DNA mismatch repair machinery (MMR) while microsatellite stable (MSS) tumors show a comparatively more "stable" mutational phenotype. Several studies demonstrated that MSI CRC generally display good prognoses for patients and immunotherapy is considered as a therapeutic option for this type of tumors. On the contrary, MSS metastatic CRC usually presents a worse prognosis and is not responsive to immunotherapy. According to this, developing new and innovative models for studying CRC response towards immune targeted therapies has become essential in the last years. Herein, we review the in vitro and in vivo models used for research in the field of immunotherapy applied to colorectal cancer

Perspective: plasticity, the enemy of the good

Plasticity is an important feature of modern cancer research. However, the level at which we should consider it remains an open question. Such debate is not new in the field of cancer and can be exemplified by the different models explaining carcinogenesis. Those models mostly explain cell transformation through the deregulation of the internal circuitry. In the last years, those models dramatically increased our knowledge and led to a series of short-term successes in terms of therapeutics. However, cancer drug resistance inevitably arises. Recently, studies on the so-called tumor microenvironment enriched the cell-centered perspective but it also enlarged the complexity of cancer etiology in particular for advanced diseases. Here, we suggest that the plastic and multi-sites specific nature of cancer combined with our incapacity to promise cure should push towards a new perspective where early clinical actions, instead of late ones, should be heralded as the priority of cancer research and care

Modeling the effects of space structure and combination therapies on phenotypic heterogeneity and drug resistance in solid tumors

International audienceHistopathological evidence supports the idea that the emergence of phenotypic heterogeneity and resistance to cytotoxic drugs can be considered as a process of selection in tumor cell populations. In this framework, can we explain intra-tumor heterogeneity in terms of selection driven by the local cell environment? Can we overcome the emergence of resistance and favor the eradication of cancer cells by using combination therapies? Bearing these questions in mind, we develop a model describing cell dynamics inside a tumor spheroid under the effects of cytotoxic and cytostatic drugs. Cancer cells are assumed to be structured as a population by two real variables standing for space position and the expression level of a phenotype of resistance to cytotoxic drugs. The model takes explicitly into account the dynamics of resources and anticancer drugs as well as their interactions with the cell population under treatment. We analyze the effects of space structure and combination therapies on phenotypic heterogeneity and chemotherapeutic resistance. Furthermore, we study the efficacy of combined therapy protocols based on constant infusion and bang-bang delivery of cytotoxic and cytostatic drugs