PS1226 DEVELOPMENT OF INNOVATIVE PRECLINICAL IN VITRO AND IN VIVO TOOLS FOR AN EFFECTIVE THERAPEUTIC STRATEGY IN PEDIATRIC ACUTE MYELOID LEUKEMIA

• Published in: HemaSphere 2019-06, Vol.3 (S1), p.559-n/a
• Main Authors: Borella, G., Bisio, V., Ros, A. Da, Tregnago, C., Benetton, M., Campodoni, E., Panseri, S., Sandri, M., Montesi, M., Cairo, S., Locatelli, F., Pigazzi, M.
• Format: Article
• Language: English
• ISSN: 2572-9241; 2572-9241
• DOI: 10.1097/01.HS9.0000563188.26522.47

Background: Diagnosis, treatment, minimal residual disease monitoring, and outcome of pediatric acute myeloid leukemia (AML) have made enormous progress during the past decade, although chemotherapy is still the pillar of pediatric treatment. Most of the emerged anti‐leukemic agents failed during experimentation, and one main limit in AML field is the inappropriateness of current pre‐clinical models used to study drug efficacy, reducing the advance of phase II and III clinical trials, especially for children. Aims: Set up and characterization of long term 3D‐AML cultures. Perform high throughput drug screening in vitro, and selection of best compounds to be then used in pre‐clinical AML‐PDX models. We would create a robust in vitro and in vivo pipeline to discover/reposition alternative treatments to improve AML children cure. Methods: The 3D structure is made up of engineered hydroxyapatite and collagen I to mimic endosteal bone marrow niche. We cultured mesenchymal stem cells derived from an AML patient (AML‐MSCs) together with its blasts. We studied 3D cultures also by using MSCs derived from healthy bone marrow donors (h‐MSCs), osteoblasts and endothelial cells. AML cells proliferation, immunophenotype and clonogenicity up to 21 days of 3D cultures have been analyzed. We characterized AML‐MSCs in comparison to h‐MSCs for proliferation rate, gene expression, secretome profile, osteogenic differentiation and anti‐inflammatory potential. We set up a drug targeting of the AML‐MSCs selecting agents among 480 compounds. We combined blasts and AML‐MSCs treatment in the 3D model. 3D‐AML cultures have been implanted in mice to generate robust pre‐clinical AML‐PDXs to study new combined treatments for AML. Results: We successfully set up 3D long‐term cultures of different primary AML (n = 20) and confirmed their proliferation up to 21 days. Clonogenic potential and immunophenotype of the original AML was also documented. We uncovered AML‐MSCs (n = 4) exhibiting an higher proliferation rate (p