Recombinant human CD19L-sTRAIL effectively targets B cell precursor acute lymphoblastic leukemia
Fatih M. Uckun, … , Osmond J. D’Cruz, Hong Ma
Fatih M. Uckun, … , Osmond J. D’Cruz, Hong Ma
Published January 26, 2015
Citation Information: J Clin Invest. 2015;125(3):1006-1018. https://doi.org/10.1172/JCI76610.
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Recombinant human CD19L-sTRAIL effectively targets B cell precursor acute lymphoblastic leukemia

Abstract

Patients with B cell precursor acute lymphoblastic leukemia (BPL) respond well to chemotherapy at initial diagnosis; however, therapeutic options are limited for individuals with BPL who relapse. Almost all BPL cells express CD19, and we recently cloned the gene encoding a natural ligand of the human CD19 receptor (CD19L). We hypothesized that fusion of CD19L to the soluble extracellular domain of proapoptotic TNF-related apoptosis-inducing ligand (sTRAIL) would markedly enhance the potency of sTRAIL and specifically induce BPL cell apoptosis due to membrane anchoring of sTRAIL and simultaneous activation of the CD19 and TRAIL receptor (TRAIL-R) apoptosis signaling pathways. Here, we demonstrate that recombinant human CD19L-sTRAIL was substantially more potent than sTRAIL and induced apoptosis in primary leukemia cells taken directly from BPL patients. CD19L-sTRAIL effectively targeted and eliminated in vivo clonogenic BPL xenograft cells, even at femtomolar-picomolar concentrations. In mice, CD19L-sTRAIL exhibited a more favorable pharmacokinetic (PK) profile than sTRAIL and was nontoxic at doses ranging from 32 fmol/kg to 3.2 pmol/kg. CD19L-sTRAIL showed potent in vivo antileukemic activity in NOD/SCID mouse xenograft models of relapsed and chemotherapy-resistant BPL at nontoxic fmol/kg dose levels. Together, these results suggest that recombinant human CD19L-sTRAIL has clinical potential as a biotherapeutic agent against BPL.

Authors

Fatih M. Uckun, Dorothea E. Myers, Sanjive Qazi, Zahide Ozer, Rebecca Rose, Osmond J. D’Cruz, Hong Ma

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Figure 4

CD19L-sTRAIL abrogates the ability of leukemia-initiating ALL xenograft cells derived from BPL patients to cause leukemia in NOD/SCID mice.

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CD19L-sTRAIL abrogates the ability of leukemia-initiating ALL xenograft ...
ALL xenograft cells (2 × 106 cells/sample) were treated with 2.1 pM CD19L-sTRAIL for 24 hours at 37°C or irradiated with 2 Gy γ-rays. Cells were washed in PBS, resuspended in PBS, and inoculated into NOD/SCID mice i.v. via tail-vein injections in a 100 μl total volume. Controls (n = 28) included untreated xenograft cells as well as xenograft cells treated with CD19L (25 nM) or sTRAIL (250 nM) for 24 hours at 37°C prior to inoculation. Mice were monitored for signs of leukemia, and all mice in a given experiment were sacrificed when any mouse developed morbidity. Histopathologic examinations were performed in 26 mice. (A and B) For each treatment group, the cumulative results for the average spleen size and nucleated spleen cell count, respectively (control: n = 22 for size, n = 14 for count); CD19L: n = 3 for size, n = 2 for count; sTRAIL: n = 3 for size, n = 3 for count; CD19L-sTRAIL: n = 24 for size, n = 20 for count;, RAD: n = 11 for size, n = 10 for count). SEM and least squares mean estimates for the planned linear contrasts were obtained from mixed ANOVA models. *P < 0.0001 vs. CON, P < 0.0001 vs. other treatments in A; *P < 0.0001 vs. CON, †P = 0.0003 vs. other treatments in B. (C) Mice challenged with untreated, CD19L-treated, or sTRAIL-treated (but not CD19L-sTRAIL–treated) BPL xenograft cells developed disseminated leukemia, with leukemic infiltrates (L) in bone marrow, kidneys, liver, and leptomeninges. Light microscopy images were taken with an EVOS XL Core Light Microscope (AMG Bothel). RAD, radiation.