Abstract 306: Selective targeting of pediatric acute lymphoblastic leukemia using CCRF-CEM CLENs: Development and characterization
Authors: Yonan Andre , Jacques Christopher , Feinberg Thanaphorn , Fletcher Tafaswa , Campbell Robert 
Published: June 2022

Background: Acute lymphoblastic leukemia (ALL) is a hematological malignancy commonly observed in children under 14 years old. A defect in the hematopoietic pathway results in the uncontrolled proliferation of B-cell and T-cell lymphocyte precursors. Treatments for ALL are patient-specific and are determined based on prognostic factors such as age, minimal residue disease, and genetic alterations. Nano-sized liposomes are drug-delivery vehicles used to enhance the delivery of drugs to target cells. The composition, size, and overall charge of nanoliposomes are determinants of targeting and influence the degree of drug uptake selectivity. The objective of this study was to design, optimize, and characterize novel cell membrane lipid-extracted nanoliposomes (CLENs) for pediatric ALL and to evaluate the degree of selectivity in comparison to relevant controls.

Methods: The ALL-cell line, CCRF-CEM, was the chosen model for ALL disease and drug selectivity studies. CCRF-CEM cells were cultured and expanded in vitro for cellular extraction purposes. The CCRF-CEM cell lipid extract (LE) was included to prepare CCRF-CEM CLENs. Phase I of evaluation included physiochemical characterization and cellular uptake studies of preparations of CLENs, including 0 to 40 mol% of CCRF-CEM LE content. Phase II of evaluation fixed the optimal LE content determined from the Phase I studies and varied the cholesterol (Chol) content (0 to 40 mol%). The control cell lines used in the study represent other hematological diseases, RPMI 8226 (multiple myeloma), K-562-GFP (chronic myeloid leukemia), and U937 (lymphoma). Conventional lipid ingredients used in preparing CCRF-CEM-CLENs include DOPC, Chol, and DPPE-rhodamine for fluorescence studies using a fluorescence microplate reader.

Results: The optimal composition (and ratio of components) for CCRF-CEM CLENs was DOPC/Chol/LE (85/10/5). Results support a significant uptake of preparation types consisting of 0% LE compared to 5% LE content (p=0.01). A similar effect was observed between 0% and 10% Chol content (p&lt;0.001). The steady inclusion of Chol (2, 5, 10%) increased the cellular uptake of CCRF-CEM CLENs by CCRF-CEM cells, above which the cellular uptake decreased. The average mean diameter for the optimized preparation type was 182 ± 44 nm (n=5). The average zeta potential was -9 ± 6 mV (n=5). Cell selectivity studies revealed an increase in the uptake of the optimized CCRF-CEM CLENs by CCRF-CEM cells when compared to U937 (p=0.002) and RPMI 8226 (p=0.002) control cells. No statistical significance was observed in uptake of the same preparations by CCRF-CEM, when compared to K-562-GFP cells (p=0.09).

Conclusion: ALL-CLENs has demonstrated promising preliminary results. Future studies will investigate mechanisms underlying formulation and cellular properties.

Citation Format: Andre Yonan, Christopher Jacques, Thanaphorn Feinberg, Tafaswa Fletcher, Robert Campbell. Selective targeting of pediatric acute lymphoblastic leukemia using CCRF-CEM CLENs: Development and characterization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 306.