Human CD34+ cells engineered to express membrane-bound tumor necrosis factor–related apoptosis-inducing ligand target both tumor cells and tumor vasculature

Abstract

Adenovirus-transduced CD34 IntroductionGenetically modified stem/progenitor cells represent an innovative approach for delivery of anticancer molecules. 1,2 Because of their homing properties, systemically injected stem/progenitor cells could infiltrate both primary and metastatic tumor sites, thus allowing tumor-specific targeting 3-9 and potentially overcoming limitations inherent to the pharmacokinetic profile of soluble drugs. [10][11][12] Soluble tumor necrosis factor (TNF)-related apoptosisinducing ligand (sTRAIL) is a proapoptotic member of the TNF superfamily of death receptor ligands. A variety of preclinical data show that sTRAIL is a cancer cell-specific molecule exerting a remarkable antitumor activity in vitro [13][14][15][16][17][18] and in vivo in athymic nude mice or in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. 13,19,20 Phase 1/2 clinical trials have demonstrated a good toxicity profile for sTRAIL but limited evidence of antitumor activity probably because of short exposure of tumor cells to low drug concentrations. 21 Because of sTRAIL's short half-life, 13,20,22 it seems unlikely that the recommended sTRAIL dose of 8 mg/kg body weight will allow prolonged exposure of tumor cells at high drug concentrations. 21 Strategies to enhance the therapeutic activity of sTRAIL include combining it with conventional chemotherapy 23 or with new agents, such as histone deacetylase inhibitors that up-regulate TRAIL-R1 and/or TRAIL-R2, resulting in a synergistic induction of apoptosis in both sTRAIL-sensitive and -resistant tumor cells. 24 Alternatively, cell-based vehiculation of the full-length, membranebound (m)TRAIL has been proposed. 11 Neural or mesenchymal stem cell-mediated mTRAIL delivery has been investigated in solid tumors. 9,[25][26][27][28] More recently, we demonstrated that intravenous injection of mTRAIL-expressing CD34 ϩ cells (CD34-TRAIL ϩ cells) efficiently act as mTRAIL-presenting vehicles and exert a potent antitumor activity in NOD/SCID mice bearing systemic multiple myeloma and non-Hodgkin lymphoma xenografts. [29][30][31] Using a subcutaneous multiple myeloma model in NOD/SCID mice, the present study aimed at investigating the antitumor mechanism(s) of mTRAIL-expressing cells by analyzing homing properties of CD34-TRAIL ϩ cells as well as the degree and distribution of tumor cell death and tumor vascular damage. To analyze the antivascular activity of CD34-TRAIL ϩ cells, we used an in vivo staining assay of tumor vasculature. 32 The imaging software ImageJ (National Institutes of Health), equipped with appropriately designed macros to specifically quantify parameters of tumor cell and tumor vascular damage, allowed the processing The online version of this article contains a data supplement.The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ''advertisement'' in accordance with 18 USC section 1734. For personal use only. on May 11, 2018. by guest www.blood...

Induction of death receptor 5 expression in tumor vasculature by perifosine restores the vascular disruption activity of TRAIL-expressing CD34+ cells

“…In order to analyze functional tumor vasculature, in vivo biotinylation was performed as previously described [40].…”

“…For each experimental condition, at least three sections from different tumor nodules were analyzed. Analysis to calculate the endothelial area (i.e., the percentage of the tissue section occupied by endothelium) and the percent of tumor necrosis expressed as (necrotic area)/(total tissue area) 9 100 were performed as previously described [40].…”

“…We have previously demonstrated that adenovirus-transduced CD34 ? cells expressing full-length membrane-bound (m)TRAIL (CD34-TRAIL 1 cells) efficiently vehiculate TRAIL within tumors and exhibit tumor-specific targeting, overcoming limitations inherent to the pharmacokinetic profile of the soluble molecule [39,40]. While the intratumor homing of CD34-TRAIL 1 cells involves interactions of SDF-1 and VCAM-1 expressed by tumor endothelial cells with their counter receptors (CXCR4 and VLA-4) expressed by transduced cells, the antitumor activity of mTRAIL requires DR5 expression by tumor vasculature [40,41].…”

“…cells expressing full-length membrane-bound (m)TRAIL (CD34-TRAIL 1 cells) efficiently vehiculate TRAIL within tumors and exhibit tumor-specific targeting, overcoming limitations inherent to the pharmacokinetic profile of the soluble molecule [39,40]. While the intratumor homing of CD34-TRAIL 1 cells involves interactions of SDF-1 and VCAM-1 expressed by tumor endothelial cells with their counter receptors (CXCR4 and VLA-4) expressed by transduced cells, the antitumor activity of mTRAIL requires DR5 expression by tumor vasculature [40,41]. Engagement of DR5 by CD34-TRAIL 1 cells seems to be a critical step that results in potent vascular disruption activity, which is a distinct property of the membrane-bound TRAIL not shared by its soluble counterpart [40,41].…”

“…While the intratumor homing of CD34-TRAIL 1 cells involves interactions of SDF-1 and VCAM-1 expressed by tumor endothelial cells with their counter receptors (CXCR4 and VLA-4) expressed by transduced cells, the antitumor activity of mTRAIL requires DR5 expression by tumor vasculature [40,41]. Engagement of DR5 by CD34-TRAIL 1 cells seems to be a critical step that results in potent vascular disruption activity, which is a distinct property of the membrane-bound TRAIL not shared by its soluble counterpart [40,41]. Because vascular targeting appears to be the first step in the complex cascade of events leading to mTRAIL-mediated tumor cell death, lack of DR5 expression in tumor vasculature represents a mechanism of resistance to CD34-TRAIL 1 cells.…”