PGE1-Containing Protocols Generate Mature (Leukemia-Derived) Dendritic Cells Directly from Leukemic Whole Blood

Abstract

Dendritic cells (DCs) and leukemia-derived DC (DCleu) are potent stimulators of various immunoreactive cells and they play a pivotal role in the (re-) activation of the immune system. As a potential treatment tool for patients with acute myeloid leukemia, we developed and analyzed two new PGE1-containing protocols (Pici-PGE1, Kit M) to generate DC/DCleu ex vivo from leukemic peripheral blood mononuclear cells (PBMCs) or directly from leukemic whole blood (WB) to simulate physiological conditions. Pici-PGE1 generated significantly higher amounts of DCs from leukemic and healthy PBMCs when compared to control and comparable amounts as the already established protocol Pici-PGE2. The proportions of sufficient DC-generation were even higher after DC/DCleu-generation with Pici-PGE1. With Kits, it was possible to generate DCs and DCleu directly from leukemic and healthy WB without induction of blast proliferation. The average amounts of generated DCs and DCleu-subgroups were comparable with all Kits. The PGE1 containing Kit M generated significantly higher amounts of mature DCs when compared to the PGE2-containing Kit K and increased the anti-leukemic-activity. In summary PGE1-containing protocols were suitable for generating DC/DCleu from PBMCs as well as from WB, which reliably (re-) activated immunoreactive cells, improved the overall ex vivo anti-leukemic activity, and influenced cytokine-release-profiles.

Dendritic Cells of Leukemic Origin: Specialized Antigen-Presenting Cells as Potential Treatment Tools for Patients with Myeloid Leukemia

“…In general, 3 steps are needed for successful generation of DC/DC leu from leukemic PBMNC, i.e., induction of hematopoietic differentiation, danger signaling, and DC/DC leu maturation [40, 48]. In a first step, substances (especially cytokines) such as granulocyte macrophage colony-stimulating factor (GM-CSF), ligand of the FLT3 receptor (FLT3 L), stem cell factor (SCF), interferon (IFN)-α, and IL-4 induce the differentiation of myeloid leukemia blasts to immature DC/DC leu .…”

“…In a second step molecules such as the bacterial lysate Picibanil, toll-like receptor (TLR) agonists, nucleic acids, or lipopolysaccharides or transforming growth factor (TGF)-β mediate a danger signaling that is crucial for the activation of DC/DC leu . In the last step, response modifiers such as tumor necrosis factor (TNF)-α, prostaglandin (PG)E 2 , PGE 1 , and INF-α are used for the induction of maturation [35, 40, 48, 50]. The combination of response modifiers can have synergistic effects on danger signaling and DC/DC leu maturation.…”

“…Picibanil (OK-432) a lysis product of Streptococcus pyogenesis , acts as a TLR agonist, and induces danger signaling as well as maturation of generated mo-DC from CD14 + progenitor cells in cancer patients [68]. Picibanil-containing protocols have been shown to be usable for generation of DC/DC leu from PBMNC from patients with AML [40, 48]. The efficiency of sufficient DC/DC leu generation was higher with PGE 1 -containing protocols (Pici- PGE-1 ) in a direct comparison to PGE 2 -containing protocols (Pici- PGE-2 ), suggesting that PGE 1 is not just responsible for the maturation of DC/DC leu but it is also involved in the induction of differentiation of leukemic blasts toward DC/DC leu [48].…”

“…Picibanil-containing protocols have been shown to be usable for generation of DC/DC leu from PBMNC from patients with AML [40, 48]. The efficiency of sufficient DC/DC leu generation was higher with PGE 1 -containing protocols (Pici- PGE-1 ) in a direct comparison to PGE 2 -containing protocols (Pici- PGE-2 ), suggesting that PGE 1 is not just responsible for the maturation of DC/DC leu but it is also involved in the induction of differentiation of leukemic blasts toward DC/DC leu [48]. We could already show that antileukemic activity is improved after stimulation of T-cell-enriched immune reactive cells with DC/DC leu generated with PGE 1 -containing protocols compared to PGE 2 -conaining ones [48].…”

“…The efficiency of sufficient DC/DC leu generation was higher with PGE 1 -containing protocols (Pici- PGE-1 ) in a direct comparison to PGE 2 -containing protocols (Pici- PGE-2 ), suggesting that PGE 1 is not just responsible for the maturation of DC/DC leu but it is also involved in the induction of differentiation of leukemic blasts toward DC/DC leu [48]. We could already show that antileukemic activity is improved after stimulation of T-cell-enriched immune reactive cells with DC/DC leu generated with PGE 1 -containing protocols compared to PGE 2 -conaining ones [48]. This effect might be explained by the different mode of action of PGE 2 and PGE 1 on prostaglandin receptors (EP receptors) with different down streaming effects [69].…”