The Human Ortholog of Granulocyte Macrophage Colony-Stimulating Factor and Interleukin-2 Fusion Protein Induces Potent Ex vivo Natural Killer Cell Activation and Maturation

Abstract

Natural killer (NK) cells are appealing cellular pharmaceuticals for cancer therapy because of their innate ability to recognize and kill tumor cells. Therefore, the development of methods that can enhance the potency in their anticancer effect would be desirable. We have previously shown that a murine granulocyte macrophage colony-stimulating factor (GM-CSF)/interleukin 2 (IL-2) fusion protein displays novel antitumor properties in vivo compared with both cytokines in combination due to recruitment of NK cells. In the present work, we have found that human ortholog of the GM-CSF/IL-2 fusion protein (a.k.a. hGIFT2) induces robust NK cell activation ex vivo with significant secretion of RANTES and a 37-fold increase in IFNγ production when compared with either IL-2 or GM-CSF single cytokine treatment or their combination. Moreover, hGIFT2 upregulates the expression of NK cell activating receptors NKp44, NKp46, and DNAM-1 (CD226), as well as CD69, CD107a, and IL-2Rβ expression. In addition, hGIFT2 promotes NK cell maturation, based on the downregulation of CD117 expression and upregulation of CD11b. This phenotype correlates with significantly greater cytotoxicity against tumor cells. At the molecular level, hGIFT2 leads to a potent activation of Janus-activated kinases (JAK) downstream of both IL-2 and GM-CSF receptors (JAK1 and JAK2, respectively) and consequently leads to a hyperphosphorylation of signal transducers and activators of transcription (STAT)1, STAT3, and STAT5. In conclusion, hGIFT2 fusokine possesses unique biochemical properties distinct from IL-2 and GM-CSF, constitutes a novel and potent tool for ex vivo NK cell activation and maturation, and may be of use for cancer cell immunotherapy. [Cancer Res 2009;69(23):9020-8]

Activation of cellular immunity and marked inhibition of liver cancer in a mouse model following gene therapy and tumor expression of GM-SCF, IL-21, and Rae-1

“…Cytokines have potent immune-regulating effects, and play important roles in tumor immunity [23,24]. GM-SCF and IL-21 augment expression of INF-γ and IL-2, improve the activity of CTL and NK cells, and inhibit growth of tumors [25,26]. Our study showed that levels of both INF-γ and IL-2 in mice treated with recombinant GM-CSF, IL-21 and Rae-1 gene expression vectors were highly expressed and negatively associated with the tumor volumes seen in tumor-bearing mice.…”

Critical roles of co‐activation receptor DNAX accessory molecule‐1 in natural killer cell immunity

“…Expression of DNAM‐1 on NK cells can also be regulated by soluble factors and cell–cell interactions . In humans, IL‐2 or IL‐15 alone or in combination with heat‐shock protein 70‐derived 14‐mer peptide, granulocyte–macrophage colony‐stimulating factor/IL‐2 fusion protein, and glucocorticoid up‐regulates DNAM‐1 expression, whereas indoleamine 2,3‐dioxygenase, transforming growth factor‐ β and chronic CD155 exposure by some tumour cells can down‐regulate DNAM‐1 expression on NK cells …”

“…Expression of DNAM-1 on NK cells can also be regulated by soluble factors and cell-cell interactions. [22][23][24][25][26] In humans, IL-2 or IL-15 alone or in combination with heat-shock protein 70-derived 14-mer peptide, granulocyte-macrophage colony-stimulating factor/IL-2 fusion protein, and glucocorticoid up-regulates DNAM-1 expression, [23][24][25] whereas indoleamine 2,3-dioxygenase, transforming growth factor-b and chronic CD155 exposure by some tumour cells can down-regulate DNAM-1 expression on NK cells. 22,26 DNAM-1 ligands CD112 and CD155 are DNAM-1Ls that belong to the nectin and nectin-like (Necl) protein families, comprising nectin 1-4 and Necl 1-5, respectively.…”

GM-CSF and IL-4 Fusion Cytokine Induces B Cell-Dependent Hematopoietic Regeneration

“…27 Recently, we generated a synthetic fusokine that is derived from the fusion of GM-CSF and IL-4 (named as GIFT4) and found that GIFT4 protein has a potent immune stimulatory property and educates naive B cells into B effector cells with anti-tumor activity. 28 Unexpectedly, we discovered that GIFT4 triggers a novel B cell function on hematopoiesis in vivo.…”