Abstract 464: AAC-11 survival pathways as therapeutic target in cancer: AAC-11 leucine-zipper domain derived peptides exert potent antitumor effects and exhibit favorable stability, pharmacokinetic and toxicology profiles

Abstract

Abstract Background: Due to their basal stress phenotype associated to transformation, cancer cells are addicted to non-mutated, non-oncogenic proteins that do not bear such vital functions in normal cells, a phenomenon referred as Non-Oncogenic Addiction (NOA). Targeting these NOAs could therefore induce selective killing of cancer cells, opening several therapeutic opportunities. Recent data suggest that the stress-related scaffold protein AAC-11 (anti-apoptosis clone 11, also known as Api5) is critically involved in cancer cells resistance to chemotherapies, metastatic potential and escape from the immune system. Methods: We have developed inactivating peptides based on the fusion of a cell penetrating sequence and portions of the leucine-zipper domain of AAC-11, which functions as a protein-protein interaction module. These peptides induce cancer cells death, through the inhibition of protein-protein interactions between AAC-11 and its partners, while sparing normal cells. We now describe further characterization of our lead peptide, JRT39, which contains residues 377 to 379 of AAC-11 linked to the cell-penetrating peptide “penetratin”. Results: In vitro, JRT39 causes cell death in a wide spectrum of cancer cell lines with IC50 ranging from 5 µM to 30 µM depending on tumor cell type. In particular, JRT39 showed selective efficacy towards primary cells from Acute Myeloid Leukemia (AML), Acute Lymphocytic Leukemia (ALL) or Sézary syndrome (SS) patients, while sparing normal hematopoietic cells, with an IC50 of 5-15 µM. Mechanistically, JRT39 induces membranolysis of cancer cells through binding to p21-activated kinase 1 (PAK1) in AML or SS cells plasma membrane, where PAK1 is overexpressed. In addition, JRT39 exerted potent anti-tumor activity in vivo in disseminated or subcutaneous AML, APL (Acute Promyelocytic Leukemia) and SS-patient derived preclinical murine models. Preliminary pharmacokinetic studies revealed that JRT39 is stable in human serum and has a plasma half-life of ~1.5-2.5 hours after intravenous (IV) administration to dogs or cynomolgus monkeys, with concentration-time data fitting 2-compartment model. Finally, JRT39 was well tolerated at 5 and 10 mg/kg after single or repeated (daily) IV injections. Conclusions: Combined, our preclinical data confirm that interfering with AAC-11-related survival pathways is a promising novel anticancer strategy and support the development of JRT39 for the treatment of cancer. Citation Format: Louise Jeammet, Emile Adicéam, Justine Habault, Anna Kaci, Jeannig Berrou, Mélanie Dupont, Nicolas Thonnart, Ewa Pasquereau-Kotula, Anne Marie-Cardine, Armand Bensussan, Marika Pla, Hervé Dombret, Claude Gardin, Martine Bagot, Jean-Christophe Rain, Hélène Sicard, Jérôme Tiollier, Thorsten Braun, Jean-Luc Poyet. AAC-11 survival pathways as therapeutic target in cancer: AAC-11 leucine-zipper domain derived peptides exert potent antitumor effects and exhibit favorable stability, pharmacokinetic and toxicology profiles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 464.