A multivalent Ara-C-prodrug nanoconjugate achieves selective ablation of leukemic cells in an acute myeloid leukemia mouse model

Victor Pallarès,Ugutz Unzueta,Aïda Falgàs,Anna Aviñó,Yáiza Núñez,Annabel García-León,Laura Sánchez-García,Naroa Serna,Alberto Gallardo,Lorena Alba-Castellón,Patricia Álamo,Jorge Sierra,Lídia Cedó,Ramon Eritja,Antonio Villaverde,Esther Vázquez,Isolda Casanova,Ramon Mangues

doi:10.1016/j.biomaterials.2021.121258

Abstract

Current therapy in acute myeloid leukemia (AML) is based on chemotherapeutic drugs administered at high doses, lacking targeting selectivity and displaying poor therapeutic index because of severe adverse effects. Here, we develop a novel nanoconjugate that combines a self-assembled, multivalent protein nanoparticle, targeting the CXCR4 receptor, with an Oligo-Ara-C prodrug, a pentameric form of Ara-C, to highly increase the delivered payload to target cells. This 13.4 nm T22-GFP-H6-Ara-C nanoconjugate selectively eliminates CXCR4+ AML cells, which are protected by its anchoring to the bone marrow (BM) niche, being involved in AML progression and chemotherapy resistance. This nanoconjugate shows CXCR4-dependent internalization and antineoplastic activity in CXCR4+ AML cells in vitro. Moreover, repeated T22-GFP-H6-Ara-C administration selectively eliminates CXCR4+ leukemic cells in BM, spleen and liver. The leukemic dissemination blockage induced by T22-GFP-H6-Ara-C is significantly more potent than buffer or Oligo-Ara-C-treated mice, showing no associated on-target or off-target toxicity and, therefore, reaching a highly therapeutic window. In conclusion, T22-GFP-H6-Ara-C exploits its 11 ligands-multivalency to enhance target selectivity, while the Oligo-Ara-C prodrug multimeric form increases 5-fold its payload. This feature combination offers an alternative nanomedicine with higher activity and greater tolerability than current intensive or non-intensive chemotherapy for AML patients.

Highlights

Over the last four decades, the 7 + 3 remission induction therapy has been the standard of care for acute myeloid leukemia (AML)
We demonstrate that the conjugation of the multivalent T22-GFP-H6 nanoparticle to a new prodrug, a pentameric form of Ara-C, accommo dates a high payload of this drug, which is used in standard care of several hematological cancers
The results showed that mice administered with 5 or 25 μg of T22-GFP-H6-Ara-C did not reduce the leukemia dissemination compared to buffer-treated mice

Summary

Introduction

Over the last four decades, the 7 + 3 remission induction therapy has been the standard of care for acute myeloid leukemia (AML). Novel therapies have been approved by the FDA to treat patients with specific molecular alterations, for instance, FLT3 or IDH inhibitors, antibody drug conjugates targeting overexpressed CD33 or CD123 surface receptors, or inhibitors of proteins that regulate leukemic cell survival or proliferation pathways, such as BCL or Hedgehog [6,7,8,9]. T22-GFP-H6 is a self-assembled protein nano particle that incorporates around 11 T22 peptidic ligands, acquiring multivalency for CXCR4 binding This property confers the nanoparticle the capacity to selectively internalize in CXCR4-overexpressing (CXCR4+) leukemic cells. The use of T22-GFP-H6-Ara-C could be more effective than equimolar doses of Oligo-Ara-C in a disseminated CXCR4+ AML mouse model

Methods

Results

Discussion

Conclusion