Antibody-Targeted HRP Associated with Indole-3-Acetic Acid Induces in Vitro Apoptosis in Hematological Tumors.

Abstract 1270 Poster Board I-292 3-Indole-acetic acid (IAA) is a growth hormone found in plants that may be oxidized by horseradish peroxidase (HRP) generating cytotoxic molecules capable of inducing injury in mammal cells, including a variety of human tumors. The aim of this study was to establish an assay based on targeting HRP to hematopoietic tumor cells using antibodies and induce apoptosis by incubation with IAA. To set up the best experimental conditions, we used two human lineages of hematologic tumors: NB4, derived from acute promyelocytic leukemia (APL) and Granta 519, from Mantle Cell Lymphoma (MCL). The targeting of HRP was performed with anti-CD33 or anti-CD19 antibodies (depending on the origin of the cell), followed by incubation with goat anti-mouse antibody conjugated with the enzyme. Eight groups of cells were incubated for 2, 8, 18, 24 and 48 hours: control, HRP targeted, HRP targeted with IAA at 1, 5 and 10 mM, cells not targeted with IAA at 1, 5 and 10 mM. Apoptosis was analyzed by flow cytometry, with anexin V-FITC and propidium iodide. The best experimental conditions for both NB4 and Granta 519 cells were achieved with incubation for 24 h with 10 mM IAA. For NB4, the group targeted with HRP and treated with 10 mM IAA for 24 hours presented 44.1% of apoptosis, whereas the control groups achieved 18.2 to 24.6% (P Disclosures No relevant conflicts of interest to declare.