UMS BioCore

Cytokines are crucial molecules for maintaining the proper functioning of the immune system. Nevertheless, a dysregulation of cytokine expression could be involved in the pathogenesis of autoimmune diseases. Interleukin (IL)-15 is a key factor for natural killer cells (NK) and CD8 T cells homeostasis, necessary to fight cancer and infections but could also be considered as a pro-inflammatory cytokine involved in autoimmune inflammatory disease, including rheumatoid arthritis, psoriasis, along with tumor necrosis factor alpha (TNF-α), IL-6, and IL-1β. The molecular mechanisms by which IL-15 exerts its inflammatory function in these diseases are still unclear. In this study, we generated an IL-15-derived molecule called NANTIL-15 (New ANTagonist of IL-15), designed to selectively inhibit the action of IL-15 through the high-affinity trimeric IL-15Rα/IL-2Rβ/γc receptor while leaving IL-15 signaling through the dimeric IL-2Rβ/γc receptor unaffected. Administrating of NANTIL-15 in healthy mice did not affect the IL-15-dependent cell populations such as NK and CD8 T cells. In contrast, we found that NANTIL-15 efficiently reduced signs of inflammation in a collagen-induced arthritis model. These observations demonstrate that the inflammatory properties of IL-15 are linked to its action through the trimeric IL-15Rα/IL-2Rβ/γc receptor, highlighting the interest of selectively targeting this receptor.

We report the chemical conjugation of recombinant Adeno Associated Virus (rAAV) capsid with various functionalities, including proteins, using a bioorthogonal strategy. rAAVs were azido-coated or DBCO-coated by chemically modifying lysine or tyrosine residues. Lysine residues were modified using a phenyl isothiocyanate anchor, and tyrosine residues using either an aryldiazonium salt or a N-methyl luminol derivative. We demonstrate anchor- dependent labelling levels, as observed with biochemical assays and mass spectrometry. Strain-promoted azide-alkyne cycloaddition (SPAAC) was then implemented and evaluated on the rAAV to append functionalities such as fluorescein, biotin and carbohydrates to the azido- coated capsids. We confirmed the efficiency of the bioorthogonal reaction and observed a stronger reactivity with dibenzylcyclooctyne (DBCO) compared to bicyclononyne (BCN). The optimized SPAAC reaction was finally used to label the viral vectors with two relevant nanobodies targeting specific immune cell receptors (CD62L and CD45). In vitro transduction assays conducted with one rAAV-nanobody conjugate demonstrated the promising targeting properties of these chemically modified vectors. Thus, we anticipate that this strategy will positively impact the field of rAAV capsid engineering and contribute in tissue-specific targeting for the optimisation of gene therapy treatments.

Evasion of apoptosis is a hallmark of tumor progression, often driven by the overexpression of anti-apoptotic proteins from the Bcl-2 family, including Mcl-1. Mcl-1 has emerged as a critical therapeutic target, particularly in chemoresistant cancers such as ovarian cancers. This anti-apoptotic protein has been involved not only in the resistance to various conventional chemotherapeutic agents, but also in the resistance to BH3-mimetic molecules targeting Bcl-2 and/or Bcl-x L proteins, leading in some cases to therapeutic failures of these innovative molecules. However, conventional Mcl-1 inhibitors are hindered by off-target effects and toxicity, especially cardiac toxicity. To address these limitations, we have designed a PROTAC targeting Mcl-1, derived from the repositioning of an oligopyridine-based inhibitor. Its efficacy was evaluated in the IGROV1-R10 ovarian cancer cell line, a chemoresistant model. Our results demonstrate 80-90% Mcl-1 degradation after 48 hours at 10 nM, as confirmed by western blot analysis. Furthermore, a comprehensive study of its physicochemical properties and pharmacokinetic parameters allowed us to characterize its entire cellular journey, from membrane permeability to ternary complex formation with the CRBN E3 ligase. This integrated approach highlights the challenges associated with PROTACs and proposes new optimization strategies to enhance their efficacy and selectivity. This work contributes to the development of targeted degradation strategies to overcome chemoresistance and paves the way for innovative anticancer therapies. • Potent and selective Mcl-1 PROTAC designed via structure-based optimization • Up to 80% Mcl-1 degradation at 10 nM after 48 hours in ovarian cancer cells. • Comprehensive physicochemical profiling was performed both in vitro and in silico. • Ternary complex formation with CRBN E3 ligase was validated in vitro and in silico. • Study advances Mcl-1 PROTAC design for treating chemoresistant cancers.