The importance of the granulocyte-colony stimulating factor in oncology

Advances in hematopoietic stem cells ex vivo expansion associated with bone marrow niche

Hematopoietic stem cells (HSCs) are an ideal source for the treatment of many hematological diseases and malignancies, as well as diseases of other systems, because of their two important features, self-renewal and multipotential differentiation, which have the ability to rebuild the blood system and immune system of the body. However, so far, the insufficient number of available HSCs, whether from bone marrow (BM), mobilized peripheral blood or umbilical cord blood, is still the main restricting factor for the clinical application. Therefore, strategies to expand HSCs numbers and maintain HSCs functions through ex vivo culture are urgently required. In this review, we outline the basic biology characteristics of HSCs, and focus on the regulatory factors in BM niche affecting the functions of HSCs. Then, we introduce several representative strategies used for HSCs from these three sources ex vivo expansion associated with BM niche. These findings have deepened our understanding of the mechanisms by which HSCs balance self-renewal and differentiation and provided a theoretical basis for the efficient clinical HSCs expansion.

In vivo evolution of antimicrobial resistance in a biofilm model of Pseudomonas aeruginosa lung infection

The evolution of antimicrobial resistance (AMR) in biofilms has been repeatedly studied by experimental evolution in vitro, but rarely in vivo. The complex microenvironment at the infection site imposes selective pressures on the bacterial biofilms, potentially influencing the development of AMR. We report here the development of AMR in an in vivo mouse model of Pseudomonas aeruginosa biofilm lung infection. The P. aeruginosa embedded in seaweed alginate beads underwent four successive lung infection passages with or without ciprofloxacin (CIP) exposure. The development of CIP resistance was assessed at each passage by population analysis of the bacterial populations recovered from the lungs of CIP-treated and control mice, with subsequent whole-genome sequencing of selected isolates. As inflammation plays a crucial role in shaping the microenvironment at the infection site, its impact was explored through the measurement of cytokine levels in the lung homogenate. A rapid development of AMR was observed starting from the second passage in the CIP-treated mice. Genetic analysis revealed mutations in nfxB, efflux pumps (mexZ), and two-component systems (parS) contribution to CIP resistance. The control group isolates exhibited mutations in the dipA gene, likely associated with biofilm dispersion. In the initial two passages, the CIP-treated group exhibited an elevated inflammatory response compared to the control group. This increase may potentially contribute to the release of mutagenic reactive oxygen species and the development of AMR. In conclusion, this study illustrates the complex relationship between infection, antibiotic treatment, and immune response.

Plasma interleukin-7 correlation with human immunodeficiency virus RNA and CD4+ T cell counts, and interleukin-5 with circulating hepatitis B virus DNA may have implications in viral control

Chronic viral infections represent a leading cause of global morbidity and mortality. Chronic HBV, HCV, and HIV infections result in cytokine perturbations that may hold key implications in understanding the complex disease mechanisms driving virus persistence and/or resolution. Here, we determined the levels of various plasma cytokines using a commercial Bio-Plex Luminex cytokine array in chronic HBV (n = 30), HCV (n = 15), and HIV (n = 40) infections and correlated with corresponding plasma viral loads (PVLs) and liver parameters. We observed differential perturbations in cytokine profiles among the study groups. The cytokines levels positively correlated with PVL and liver transaminases. The monocyte-derived cytokines viz., MIP-1β, IL-8, and TNF-α, and Th2 cytokines like IL-4, IL-5, and IL-13 showed a better correlation with liver enzymes as compared to their corresponding PVLs. Our investigation also identified two cytokines viz., IL-5 and IL-7 that inversely correlated with HBV DNA and HIV PVLs, respectively. Regression analysis adjusted for age showed that every increase of IL-5 by one unit was associated with a reduction in HBV PVL by log10 0.4, whereas, every elevation by a unit of IL-7 was associated with decreased HIV PVL by log10 2.5. We also found that IL-7 levels correlated positively with absolute CD4+ T cell counts in HIV-infected patients. We concluded that plasma IL-5 and IL-7 may likely have a key role on viral control in HBV and HIV infections, respectively. A noteworthy increase in cytokines appears to bear protective and pathological significance, and indeed is reflective of the host's versatile immune armory against viral persistence.

Granulocyte colony-stimulating factor in bronchoalveolar lavage fluid is a potential biomarker for prognostic prediction of idiopathic pulmonary fibrosis

BACKGROUND/AIMS

Neutrophilia is frequently observed in bronchoalveolar lavage fluid (BALF) of idiopathic pulmonary fibrosis (IPF) patients. Granulocyte colony-stimulating factor (G-CSF) is a potent neutrophil-activating glycoprotein. However, the clinical implications of G-CSF remain poorly understood.in patients with IPF. Therefore, we evaluated the relationship between the G-CSF concentration in BALF and the progression of fibrosis, including in terms of the decline in lung function and long-term survival rate.

METHODS

G-CSF concentrations were measured in BALF using enzyme-linked immunosorbent assay (ELISA). The survival rate was estimated using Kaplan-Meier survival analyses.

RESULTS

G-CSF protein levels were significantly higher in IPF (n = 87; 1.88 [0 to 5.68 pg/mL]), nonspecific interstitial pneumonia (n = 22; 0.58 [0 to 11.64 pg/mL]), and hypersensitivity pneumonitis (n = 19; 2.48 [0.46 to 5.71 pg/mL]) patients than in normal controls (n = 33; 0 [0 to 0.68 pg/mL]) (all p < 0.01). A receiver operating characteristic curve showed a difference in G-CSF levels between IPF and NC (area under the curve, 0.769): The G-CSF cut-off of 0.96 pg/mL indicated 84.9% specificity and 63.2% sensitivity for IPF. The survival rate was significantly lower in the group with G-CSF > 2.872 pg/mL than in the group with ≤ 2.872 pg/mL (hazard ratio, 2.69; p = 0.041). The annual decline in diffusing capacity of the lung for carbon monoxide was positively correlated with the G-CSF level (p = 0.018).

CONCLUSION

G-CSF may participate in the development of IPF and be useful for predicting the prognosis of IPF. Therefore, G-CSF should be analyzed in BALF, in addition to differential cell counts.

Novel G-CSF conjugated anionic globular dendrimer: Preparation and biological activity assessment

The most crucial role of granulocyte colony-stimulating factor (G-CSF) in the body is to increase the strength of immune system. In recent years, research on the use of nanoparticles in pharmaceuticals has been considered, most of which have been for drug-loading purposes. In this study, a novel G-CSF conjugated dendrimer was synthesized and characterized using different techniques. In vitro cytotoxicity was assessed on A549 and L929 cells, while abnormal toxicity was studied in mice. In vitro and in vivo biological activities were assessed in NFS60 cells and rats, respectively. In addition, in vivo distribution, plasma half-life, and histopathological effect were studied in rat. The characterization tests confirmed the successful conjugation. There was no difference between G-CSF cytotoxicity before and after conjugation, and no difference with the control group. No mice showed abnormal toxicity. Although in vitro biological activity revealed both conjugated and free G-CSF promote proliferation cells, biological activity decreased significantly after conjugation about one-third of the unconjugated form. Nonetheless, in vivo biological activity of conjugated G-CSF increased by more than 2.5-fold relative to the unconjugated form, totally. Fortunately, no histopathologic adverse effect was observed in vital rat tissues. Also, in vivo distribution of the conjugate was similar to the native protein with an enhanced terminal half-life. Our data revealed that G-CSF conjugated dendrimer could be considered as a candidate to improve the in vivo biological activity of G-CSF. Moreover, multivalent capability of the dendrimer may be used for other new potentials of G-CSF in future perspectives.

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.

Improving the Expression of Human Granulocyte Colony Stimulating Factor in Escherichia coli by Reducing the GC-content and Increasing mRNA Folding Free Energy at 5'-Terminal End

Purpose: Strategy for improving the production of biopharmaceutical protein continues to develop due to increasing market demand. Human granulocyte colony stimulating factor (hG-CSF) is one of biopharmaceutical proteins that has many applications, and easily produced in Escherichia coli expression system. Previous studies reported that codon usage, rare codon, mRNA folding and GC-content at 5’-terminal end were crucial for protein production in E. coli. In the present study, the effect of reducing the GC-content and increasing the mRNA folding free energy at the 5’-terminal end on the expression level of hG-CSF proteins was investigated.

Methods: Synonymous codon substitutions were performed to generate mutant variants of open reading frame (ORF) with lower GC-content at 5’-terminal ends. Oligoanalyzer tool was used to calculate the GC content of eight codons sequence after ATG. Whereas, mRNA folding free energy was predicted using KineFold and RNAfold tools. The template DNA was amplified using three variant forward primers and one same reverse primer. Those DNA fragments were individually cloned into pJexpress414 expression vector and were confirmed using restriction and DNA sequencing analyses. The confirmed constructs were transformed into E. coli NiCo21(DE3) host cells and the recombinant protein was expressed using IPTG-induction. Total protein obtained were characterized using SDS-PAGE, Western blot and ImageJ software analyses.

Results: The result showed that the mutant variant with lower GC-content and higher mRNA folding free energy near the translation initiation region (TIR) could produce a higher amount of hG-CSF proteins compared to the original gene sequence.

Conclusion: This study emphasized the important role of the nucleotide composition immediately downstream the start codon to achieve high-yield protein product on heterologous expression in E. coli.

Gene activation by a CRISPR-assisted trans enhancer

The deactivated CRISPR/Cas9 (dCas9) is now the most widely used gene activator. However, current dCas9-based gene activators are still limited by their unsatisfactory activity. In this study, we developed a new strategy, the CRISPR-assisted trans enhancer, for activating gene expression at high efficiency by combining dCas9-VP64/sgRNA with the widely used strong CMV enhancer. In this strategy, CMV enhancer DNA was recruited to target genes in trans by two systems: dCas9-VP64/csgRNA-sCMV and dCas9-VP64-GAL4/sgRNA-UAS-CMV. The former recruited trans enhancer by annealing between two short complementary oligonucleotides at the ends of the sgRNA and trans enhancer. The latter recruited trans enhancer by binding between GAL4 fused to dCas9 and UAS sequence of trans enhancer. The trans enhancer activated gene transcription as the natural looped cis enhancer. The trans enhancer could activate both exogenous reporter genes and variant endogenous genes in various cells, with much higher activation efficiency than that of current dCas9 activators.

Block of Granulocyte-Macrophage Colony-Stimulating Factor Prevents Inflammation-Induced Preterm Birth in a Mouse Model for Parturition

OBJECTIVE

A multitude of factors promotes inflammation in the reproductive tract leading to preterm birth. Macrophages peak in the cervix prior to birth and their numbers are increased by the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF). We hypothesize GM-CSF is produced from multiple sites in the genital tract and is a key mediator in preterm birth.

STUDY DESIGN

Ectocervical, endocervical, and amniotic fluid mesenchymal stem cells were treated with lipopolysaccharide (LPS), and the concentration and expression of GM-CSF was measured. Pregnant CD-1 mice on gestational day 17 received LPS and an intravenous injection of either anti-mouse GM-CSF or control antibody. After 6 hours, the preterm birth rate was recorded.

RESULTS

Treatment with LPS increased the GM-CSF concentration and messenger RNA expression after 24 hours in all 3 cell lines ( P < .01). Mice treated with LPS and the GM-CSF antibody had a preterm birth rate of 25%, compared to a 66.7% preterm birth rate in controls, within 6 hours ( P < .05, χ²). Treatment with the anti-mouse GM-CSF antibody decreased the concentration of GM-CSF in the mouse serum ( P < .01) but did not alter the number of macrophages or collagen content in the cervix.

CONCLUSION

These studies demonstrate that GM-CSF is produced from multiple sites in the genital tract and that treatment with an antibody to GM-CSF prevents preterm birth. Curiously, the anti-mouse GM-CSF antibody did not decrease the number of macrophages in the cervix. Further research is needed to determine whether antibodies to GM-CSF can be utilized as a therapeutic agent to prevent preterm birth.

Mathematical Analysis of Cytokine-Induced Differentiation of Granulocyte-Monocyte Progenitor Cells

Granulocyte-monocyte progenitor (GMP) cells play a vital role in the immune system by maturing into a variety of white blood cells, including neutrophils and macrophages, depending on exposure to cytokines such as various types of colony stimulating factors (CSF). Granulocyte-CSF (G-CSF) induces granulopoiesis and macrophage-CSF (M-CSF) induces monopoiesis, while granulocyte/macrophage-CSF (GM-CSF) favors monocytic and granulocytic differentiation at low and high concentrations, respectively. Although these differentiation pathways are well documented, the mechanisms behind the diverse behavioral responses of GMP cells to CSFs are not well understood. In this paper, we propose a mechanism of interacting CSF-receptors and transcription factors that control GMP differentiation, convert the mechanism into a set of differential equations, and explore the properties of this mathematical model using dynamical systems theory. Our model reproduces numerous experimental observations of GMP cell differentiation in response to varying dosages of G-CSF, M-CSF, and GM-CSF. In particular, we are able to reproduce the concentration-dependent behavior of GM-CSF induced differentiation, and propose a mechanism driving this behavior. In addition, we explore the differentiation of a fourth phenotype, monocytic myeloid-derived suppressor cells (M-MDSC), showing how they might fit into the classical pathways of GMP differentiation and how progenitor cells can be primed for M-MDSC differentiation. Finally, we use the model to make novel predictions that can be explored by future experimental studies.

IL-35 induces N2 phenotype of neutrophils to promote tumor growth

IL-35 is an immunosuppressive cytokine and exerts regulatory effects on T cells, B cells, macrophages and dendritic cells. Neutrophils are important innate immune cells that play key roles in tumor development. The effect of IL-35 on neutrophils remains unknown. Here, we report that IL-35 can induce N2 neutrophil polarization (protumor phenotype) by increasing G-CSF and IL-6 production, and promote neutrophil infiltration into tumor microenvironment. The sustained expression of IL-35 could promote chronic inflammation to augment the proangiogenic and immunosuppressive function of neutrophils. IL-35 stimulated macrophages to secrete proinflammatory cytokines IL-1β and IL-6. IL-1β stimulated γδ T cells to produce IL-17, which in turn increased the production of G-CSF. By increasing the expression of G-CSF and IL-6, IL-35 could up-regulate the expression of MMP-9 and Bv8, and down-regulate TRAIL expression in neutrophils, thus augmenting the proangiogenic function of neutrophils. Moreover, G-CSF/IL-6 induced the enhanced activation of STAT3 and ERK pathways in neutrophils, thus increasing the expression of iNOS to suppress T cell activation. Our findings suggest that IL-35 can promote tumor progression by functioning as an up-stream cytokine to promote cancer-associated inflammation and control neutrophil polarization. Targeting IL-35 might be an important approach for designing new strategy of tumor therapy.

Calf Spleen Extractive Injection protects mice against cyclophosphamide-induced hematopoietic injury through G-CSF-mediated JAK2/STAT3 signaling

Calf Spleen Extractive Injection (CSEI), extracted from the spleen of healthy cows (within 24 hours of birth), is a small-peptide-enriched extraction and often used as an ancillary agent in cancer therapy. This study evaluated the hematopoietic function of CSEI and its underlying mechanisms, principally in CHRF, K562 cells, BMNCs and a mouse model of cyclophosphamide (CTX)-induced hematopoietic suppression. CSEI promoted the proliferation and differentiation of CHRF and K562 cells, activated hematopoietic- and proliferation-related factors RSK1p90, ELK1 and c-Myc, and facilitated the expression of differentiation- and maturation-related transcription factors GATA-1, GATA-2. In the mice with hematopoietic suppression, 3 weeks of CSEI administration enhanced the bodyweights and thymus indices, suppressed the spleen indices and strongly elevated the production of HSPCs, neutrophils and B cells in bone marrow, ameliorated bone marrow cellularity, and regulated the ratio of peripheral blood cells. Proteome profiling combined with ELISA revealed that CSEI regulated the levels of cytokines, especially G-CSF and its related factors, in the spleen and plasma. Additional data revealed that CSEI promoted phosphorylation of STAT3, which was stimulated by G-CSF in both mice spleen and cultured BMNCs. Taken together, CSEI has the potential to improve hematopoietic function via the G-CSF-mediated JAK2/STAT3 signaling pathway.

Interleukin-3 Prevents Cellular Death Induced by Oxidative Stress in HEK293 Cells

Interleukin-3 (IL-3) is a well-characterized growth factor in hematopoietic cells, but it is also expressed in other cell types with poorly described functions. Many studies have provided evidence that IL-3 plays an important role in cell survival. We have previously shown that IL-3 is able to increase glucose uptake in HEK293 cells, suggesting that this factor requires sustained glucose metabolism to promote cell survival. In this study, we demonstrate that IL-3 contributes to cell survival under oxidative stress, a prominent feature in the pathophysiology of cancer, diabetes, and neurodegenerative diseases, as well as in the aging process. Our results suggest a molecular mechanism that involves signaling pathways mediated by PI-3k/Akt and Erk. Altogether, these findings show an important role for IL-3 in supporting the viability of non-hematopoietic systems. J. Cell. Biochem. 118: 1330-1340, 2017. © 2016 Wiley Periodicals, Inc.

14,15-EET induces the infiltration and tumor-promoting function of neutrophils to trigger the growth of minimal dormant metastases

Infiltrating neutrophils are known to promote in the development of tumor. However, it is unclear whether and how neutrophils are involved in triggering the growth of dormant metastases. Here we show that 14,15-epoxyeicosatrienoic acid (14,15-EET) can trigger the growth of dormant micrometastases by inducing neutrophilic infiltration and converting neutrophil function. 14,15-EET triggered neutrophil infiltration in metastatic lesions by activating STAT3 and JNK pathways to induce the expression of human IL-8 and murine CXCL15 in corresponding tumor cells. The continuous expression of hIL-8/mCXCL15 was maintained by the sustained and enhanced activation of JNK pathway. 14,15-EET up-regulated miR-155 expression by activating STAT3 and JNK pathways. miR-155 in turn down-regulated the expression of SHIP1 and DET1, thus augmenting the activation of JNK and c-Jun. Moreover, the function of neutrophils was converted from tumor-suppressing to tumor-promoting by 14,15-EET in vivo. By inducing the production of G-CSF/IL-6 in vivo, 14,15-EET induced the enhancement of STAT3 activation in neutrophils to increase MMP-9 expression and decrease TRAIL expression. Neutrophil-derived MMP-9 was required for 14,15-EET to induce angiogenesis during the growth of dormant micrometastases. Depleting neutrophils or inhibiting hIL-8/mCXCL15 up-regulation resulted in the failure of 14,15-EET to promote the development of micrometastases. These findings reveal a mechanism through which the infiltration and tumor-promoting function of neutrophils could be induced to trigger the growth of dormant metastases, which might be a driving force for the tumor recurrence based on dormant metastases.