Administration of granulocyte colony-stimulating factor induces hyporesponsiveness to lipopolysaccharide and impairs antigen-presenting function of peripheral blood monocytes

Contrasting Immunopathogenic and Therapeutic Roles of Granulocyte Colony-Stimulating Factor in Cancer

Tumor cells are particularly adept at exploiting the immunosuppressive potential of neutrophils as a strategy to achieve uncontrolled proliferation and spread. Recruitment of neutrophils, particularly those of an immature phenotype, known as granulocytic myeloid-derived suppressor cells, is achieved via the production of tumor-derived granulocyte colony-stimulating factor (G-CSF) and neutrophil-selective chemokines. This is not the only mechanism by which G-CSF contributes to tumor-mediated immunosuppression. In this context, the G-CSF receptor is expressed on various cells of the adaptive and innate immune systems and is associated with induction of T cell polarization towards the Th2 and regulatory T cell (Treg) phenotypes. In contrast to the potentially adverse effects of sustained, endogenous production of G-CSF by tumor cells, stringently controlled prophylactic administration of recombinant (r) G-CSF is now a widely practiced strategy in medical oncology to prevent, and in some cases treat, chemotherapy-induced severe neutropenia. Following an overview of the synthesis, structure and function of G-CSF and its receptor, the remainder of this review is focused on: (i) effects of G-CSF on the cells of the adaptive and innate immune systems; (ii) mechanisms by which this cytokine promotes tumor progression and invasion; and (iii) current clinical applications and potential risks of the use of rG-CSF in medical oncology.

Myeloid Engraftment in Humanized Mice: Impact of Granulocyte-Colony Stimulating Factor Treatment and Transgenic Mouse Strain

Poor myeloid engraftment remains a barrier to experimental use of humanized mice. Focusing primarily on peripheral blood cells, we compared the engraftment profile of NOD-scid-IL2Rγc(-/-) (NSG) mice with that of NSG mice transgenic for human membrane stem cell factor (hu-mSCF mice), NSG mice transgenic for human interleukin (IL)-3, granulocyte-macrophage-colony stimulating factor (GM-CSF), and stem cell factor (SGM3 mice). hu-mSCF and SGM3 mice showed enhanced engraftment of human leukocytes compared to NSG mice, and this was reflected in the number of human neutrophils and monocytes present in these strains. Importantly, discrete classical, intermediate, and nonclassical monocyte populations were identifiable in the blood of NSG and hu-mSCF mice, while the nonclassical population was absent in the blood of SGM3 mice. Granulocyte-colony stimulating factor (GCSF) treatment increased the number of blood monocytes in NSG and hu-mSCF mice, and neutrophils in NSG and SGM3 mice; however, this effect appeared to be at least partially dependent on the stem cell donor used to engraft the mice. Furthermore, GCSF treatment resulted in a preferential expansion of nonclassical monocytes in both NSG and hu-mSCF mice. Human tubulointerstitial CD11c(+) cells were present in the kidneys of hu-mSCF mice, while monocytes and neutrophils were identified in the liver of all strains. Bone marrow-derived macrophages prepared from NSG mice were most effective at phagocytosing polystyrene beads. In conclusion, hu-mSCF mice provide the best environment for the generation of human myeloid cells, with GCSF treatment further enhancing peripheral blood human monocyte cell numbers in this strain.

Mobilization of healthy donors with plerixafor affects the cellular composition of T-cell receptor (TCR)-αβ/CD19-depleted haploidentical stem cell grafts

BACKGROUND

HLA-haploidentical hematopoietic stem cell transplantation (HSCT) is suitable for patients lacking related or unrelated HLA-matched donors. Herein, we investigated whether plerixafor (MZ), as an adjunct to G-CSF, facilitated the collection of mega-doses of hematopoietic stem cells (HSC) for TCR-αβ/CD19-depleted haploidentical HSCT, and how this agent affects the cellular graft composition.

METHODS

Ninety healthy donors were evaluated. Single-dose MZ was given to 30 'poor mobilizers' (PM) failing to attain ≥40 CD34+ HSCs/μL after 4 daily G-CSF doses and/or with predicted apheresis yields ≤12.0x106 CD34+ cells/kg recipient's body weight.

RESULTS

MZ significantly increased CD34+ counts in PM. Naïve/memory T and B cells, as well as natural killer (NK) cells, myeloid/plasmacytoid dendritic cells (DCs), were unchanged compared with baseline. MZ did not further promote the G-CSF-induced mobilization of CD16+ monocytes and the down-regulation of IFN-γ production by T cells. HSC grafts harvested after G-CSF + MZ were enriched in myeloid and plasmacytoid DCs, but contained low numbers of pro-inflammatory 6-sulfo-LacNAc+ (Slan)-DCs. Finally, children transplanted with G-CSF + MZ-mobilized grafts received greater numbers of monocytes, myeloid and plasmacytoid DCs, but lower numbers of NK cells, NK-like T cells and Slan-DCs.

CONCLUSIONS

MZ facilitates the collection of mega-doses of CD34+ HSCs for haploidentical HSCT, while affecting graft composition.

Granulocyte colony-stimulating-factor-induced psoriasiform dermatitis resembles psoriasis with regard to abnormal cytokine expression and epidermal activation

Psoriasis is a chronic inflammatory skin disorder characterized by accumulation of Th1-type T cells and neutrophils, regenerative keratinocyte proliferation and differentiation, and enhanced epidermal production of antimicrobial peptides. The underlying cause is unknown, but there are some similarities with the immunologic defense program against bacteria. Development of psoriasiform skin lesions has been reported after administration of granulocyte colony-stimulating factor (G-CSF), a cytokine induced in monocytes by bacterial antigens. To further investigate the relation between this type of cytokine-induced dermatitis and psoriasis, we analyzed the cutaneous cytokine profile [tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, transforming growth factor-beta1 (TGF-beta1), interleukin-10 (IL-10), IL-12p35 and p40, and IL-8] and expression of markers of epidermal activation [Ki-67, cytokeratin-16, major histocompatibility complex (MHC) class II, intercellular adhesion molecule-1 (ICAM-1)] in a patient who developed G-CSF-induced psoriasiform dermatitis by using quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistology. The histologic picture resembled psoriasis with regard to epidermal hyperparakeratosis and the accumulation of lymphocytes in the upper corium. CD8(+) T cells were found to infiltrate the epidermis which was associated with an aberrant expression of Ki-67, cytokeratin-16, MHC class II, and ICAM-1 on adjacent keratinocytes. As compared to normal skin (n = 7), there was an increased expression of TNF-alpha, IL-12p40, and IL-8, a decreased expression of TGF-beta1, and a lack of IL-10, similar to the findings in active psoriasis (n = 8). Therefore, G-CSF may cause a lymphocytic dermatitis that, similar to psoriasis, is characterized by a pro-inflammatory Th1-type cytokine milieu and an epidermal phenotype indicative of aberrant maturation and acquisition of non-professional immune functions.

Elevation of serum hepatocyte growth factor during granulocyte colony-stimulating factor-induced peripheral blood stem cell mobilization

We examined serum levels of the angiogenic factors, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF), in normal donors for allogeneic peripheral blood stem cell (PBSC) transplantation. Granulocyte colony-stimulating factor (G-CSF) (filgrastim 400 microg/m2/d) was administered to 23 donors for 5 d and aphereses were performed on days 4 and 5. Although bFGF remained at similar levels after G-CSF treatment, serum VEGF and HGF levels increased 1.5-fold (n = 13; P = 0.02) and 6.8-fold (n = 23; P < 0.0001) respectively. The serum HGF level before G-CSF administration on day 1 correlated inversely with mobilized CD34+ cell numbers. Time course kinetics of HGF showed that on the day after G-CSF administration (day 2), serum HGF levels increased to 3678 pg/ml. For auto PBSC mobilization with chemotherapy and G-CSF 200 microg/m2/d (n = 8), we observed similar HGF elevation, which appeared to be dose-dependent on the G-CSF administered.

Selective activation of STAT3 in human monocytes stimulated by G-CSF: implication in inhibition of LPS-induced TNF-alpha production

Lipopolysaccharide (LPS) induced tumor necrosis factor (TNF)-alpha production in human monocytes, which was dependent on activation of extracellular signal-regulated kinase (ERK), p38, c-Jun NH(2)-terminal kinase (JNK), and nuclear factor (NF)-kappa B. LPS-induced TNF-alpha production was inhibited by granulocyte colony-stimulating factor (G-CSF) and interleukin (IL)-10. G-CSF, like IL-10, exerted the inhibitory effect even when simultaneously added with LPS. Among the signaling pathways, signal transducer and activator of transcription 3 (STAT3) was selectively activated in monocytes stimulated by G-CSF or IL-10. G-CSF-mediated inhibition of LPS-induced TNF-alpha production as well as G-CSF-induced STAT3 phosphorylation and suppressor of cytokine signaling 3 mRNA expression were prevented by pretreatment of monocytes with AG-490, an inhibitor of Janus kinase 2. G-CSF did not affect LPS-induced activation of ERK, p38, JNK, and NF-kappa B, indicating that G-CSF affects the pathway downstream or independently of these signaling molecules. G-CSF-induced, but not IL-10-induced, STAT3 phosphorylation was attenuated in the presence of LPS. These findings suggest that G-CSF, like IL-10, inhibits LPS-induced TNF-alpha production in human monocytes through selective activation of STAT3, and the immunomodulation observed in vivo by G-CSF administration may be partly ascribed to the direct effect of G-CSF on monocyte functions.

Granulocyte colony-stimulating factor directly affects human monocytes and modulates cytokine secretion

OBJECTIVE

Recent reports have indicated that monocytes express receptors for the granulocyte colony-stimulating factor (G-CSF). The direct effects of G-CSF on cytokine secretion in monocytes were examined.

MATERIALS AND METHODS

A monocytic cell line NOMO-1 that secretes multiple cytokines upon stimulation with lipopolysaccharide (LPS) was used. Normal human monocytes were purified by negative selection using magnetic beads. Cells pretreated with or without G-CSF were stimulated with LPS, and the subsequent concentrations of cytokines and chemokines in supernatants were determined by sandwich enzyme-linked immunosorbent assay.

RESULTS

NOMO-1 cells were found to express receptors for G-CSF. Although G-CSF stimulation did not induce cytokine secretion, pretreatment with G-CSF significantly attenuated LPS-stimulated secretion of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin (IL)-12 in NOMO-1 cells. Simultaneously, however, G-CSF pretreatment apparently enhanced LPS-induced secretion of IL-10 and monocyte chemoattractant protein-1, whereas secretions of IL-1beta, IL-6, and IL-8 were unaffected. When normal human monocytes from healthy volunteers were similarly examined, marked individual variations in LPS-induced secretion of cytokines were observed. Although some exceptions exist, a similar tendency as to the effects of G-CSF treatment on cytokine secretions as that in NOMO-1 cells was observed in human monocytes.

CONCLUSIONS

Our data suggest that G-CSF directly affects monocytes and modulates their cytokine secretion. NOMO-1 cells can provide an alternate model for in vitro culture of monocytes to investigate the effects of G-CSF on cytokine secretion by these cells.