Granulocyte-colony stimulating factor-producing pancreatic adenosquamous carcinoma showing aggressive clinical course

Characterizing the Inflammatory Profile of Neutrophil-Rich Triple-Negative Breast Cancer

Breast cancer (BC) is one of the most common types of cancer in women in the United Arab Emirates. Immunogenic tumours, such as triple-negative breast cancer (TNBC), show increased neutrophil infiltration, which is associated with poor prognosis and limited efficacy of immunotherapy. This study aims to investigate in vitro the bidirectional effect of neutrophils on metastatic TNBC (MDA-MB-231) compared to less-metastatic luminal breast cancer (MCF-7) cell lines. We found that BC cells or their conditioned medium (CM) reduced the viability of neutrophil-like cells (HL60). This was supported by increased cellular stress and NETosis in differentiated HL60 cells (dHL60) upon exposure to MDA-MB-231 compared to MCF-7-CM using nucleic acid staining essays. Flow cytometry showed comparable expression of inflammatory markers by polymorphonuclear cells (PMN) when treated with MDA-MB-231-CM and standard polarizing cocktails. Furthermore, MDA-MB-231-CM triggered an inflammatory pattern with evidence of stronger adhesion (CD62L) and degranulation (CD11b and CD66b) phenotypes. The proinflammatory polarization of dHL60 by MDA-MB-231-CM was additionally confirmed by the elevated CD54 expression, myeloperoxidase, and CD11b protein levels, which matched an increased transwell migratory capacity. In conclusion, BC might use neutrophils to their benefit through NETosis and complement system activation, which makes this crosstalk a potential mechanism for understanding tumour progression.

G-CSF Is a Novel Mediator of T-Cell Suppression and an Immunotherapeutic Target for Women with Colon Cancer

PURPOSE

G-CSF enhances colon cancer development. This study defines the prevalence and effects of increased G-CSF signaling in human colon cancers and investigates G-CSF inhibition as an immunotherapeutic strategy against metastatic colon cancer.

EXPERIMENTAL DESIGN

Patient samples were used to evaluate G-CSF and G-CSF receptor (G-CSFR) levels by IHC with sera used to measure G-CSF levels. Peripheral blood mononuclear cells were used to assess the rate of G-CSFR+ T cells and IFNγ responses to chronic ex vivo G-CSF. An immunocompetent mouse model of peritoneal metastasis (MC38 cells in C57Bl/6J) was used to determine the effects of G-CSF inhibition (αG-CSF) on survival and the tumor microenvironment (TME) with flow and mass cytometry.

RESULTS

In human colon cancer samples, the levels of G-CSF and G-CSFR are higher compared to normal colon tissues from the same patient. High patient serum G-CSF is associated with increases in markers of poor prognosis, (e.g., VEGF, IL6). Circulating T cells from patients express G-CSFR at double the rate of T cells from controls. Prolonged G-CSF exposure decreases T cell IFNγ production. Treatment with αG-CSF shifts both the adaptive and innate compartments of the TME and increases survival (HR, 0.46; P = 0.0237) and tumor T-cell infiltration, activity, and IFNγ response with greater effects in female mice. There is a negative correlation between serum G-CSF levels and tumor-infiltrating T cells in patient samples from women.

CONCLUSIONS

These findings support G-CSF as an immunotherapeutic target against colon cancer with greater potential benefit in women.

Neutrophils in Cancer and Potential Therapeutic Strategies Using Neutrophil-Derived Exosomes

Neutrophils are the most abundant immune cells and make up about 70% of white blood cells in human blood and play a critical role as the first line of defense in the innate immune response. They also help regulate the inflammatory environment to promote tissue repair. However, in cancer, neutrophils can be manipulated by tumors to either promote or hinder tumor growth depending on the cytokine pool. Studies have shown that tumor-bearing mice have increased levels of neutrophils in peripheral circulation and that neutrophil-derived exosomes can deliver various cargos, including lncRNA and miRNA, which contribute to tumor growth and degradation of extracellular matrix. Exosomes derived from immune cells generally possess anti-tumor activities and induce tumor-cell apoptosis by delivering cytotoxic proteins, ROS generation, H2O2 or activation of Fas-mediated apoptosis in target cells. Engineered exosome-like nanovesicles have been developed to deliver chemotherapeutic drugs precisely to tumor cells. However, tumor-derived exosomes can aggravate cancer-associated thrombosis through the formation of neutrophil extracellular traps. Despite the advancements in neutrophil-related research, a detailed understanding of tumor-neutrophil crosstalk is still lacking and remains a major barrier in developing neutrophil-based or targeted therapy. This review will focus on the communication pathways between tumors and neutrophils, and the role of neutrophil-derived exosomes (NDEs) in tumor growth. Additionally, potential strategies to manipulate NDEs for therapeutic purposes will be discussed.

GZMKhigh CD8+ T effector memory cells are associated with CD15high neutrophil abundance in non-metastatic colorectal tumors and predict poor clinical outcome

CD8⁺ T cells are a major prognostic determinant in solid tumors, including colorectal cancer (CRC). However, understanding how the interplay between different immune cells impacts on clinical outcome is still in its infancy. Here, we describe that the interaction of tumor infiltrating neutrophils expressing high levels of CD15 with CD8⁺ T effector memory cells (T_EM) correlates with tumor progression. Mechanistically, stromal cell-derived factor-1 (CXCL12/SDF-1) promotes the retention of neutrophils within tumors, increasing the crosstalk with CD8⁺ T cells. As a consequence of the contact-mediated interaction with neutrophils, CD8⁺ T cells are skewed to produce high levels of GZMK, which in turn decreases E-cadherin on the intestinal epithelium and favors tumor progression. Overall, our results highlight the emergence of GZMK^high CD8⁺ T_EM in non-metastatic CRC tumors as a hallmark driven by the interaction with neutrophils, which could implement current patient stratification and be targeted by novel therapeutics.

Programmed cell death ligand 1 measurement study in granulocyte colony-stimulating factor-producing lung cancer: an observational study

Background

Granulocyte colony-stimulating factor (G-CSF)-producing lung cancer induces severe inflammation and a high white blood cell (WBC) count and is associated with poor prognosis. A recent case of G-CSF-producing lung adenocarcinoma showed high expression of programmed cell death ligand 1 (PD-L1) and was treated with pembrolizumab as first-line therapy, which was extremely effective. We hypothesized that G-CSF-producing lung cancers are associated with high PD-L1 expression.

Methods

This retrospective study included patients diagnosed with lung cancer at Yokohama Municipal Citizen’s Hospital (Kanagawa, Japan) between 2009 and 2019. The PD-L1 status of 13 patients with high plasma G-CSF levels (≥40 pg/mL) was assessed by conducting immunohistochemical analysis of tissue samples.

Results

Of the total patients, 11 were men and 2 were women, with a median age of 74 years (70–85 years). Four, five, and three patients had adenocarcinoma, squamous cell carcinoma, and others, respectively. The median G-CSF level and WBC count were 85.5 pg/mL (range, 40.8–484 pg/mL) and 15,550/μL (range, 6,190–56,800/μL), respectively. The PD-L1 tumor proportion scores (TPSs) were ≥50%, 1%–49%, and <1% in 9, 1, and 3 patients, respectively. The median overall survival time was 7.3 months. Pembrolizumab was administered in six patients as first-line treatment, with two patients showing partial response, one patient with stable disease, and three patients with progressive disease. All six patients had a PD-L1 TPS of ≥50%.

Conclusion

G-CSF-producing lung cancers may be associated with increased PD-L1 expression. Although immune checkpoint inhibitors are an important treatment option for G-CSF-producing tumors, their effects are limited.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10065-w.

Mitigating the prevalence and function of myeloid-derived suppressor cells by redirecting myeloid differentiation using a novel immune modulator

BACKGROUND

Immune suppression is common in neoplasia and a major driver is tumor-induced myeloid dysfunction. Yet, overcoming such myeloid cell defects remains an untapped strategy to reverse suppression and improve host defense. Exposure of bone marrow progenitors to heightened levels of myeloid growth factors in cancer or following certain systemic treatments promote abnormal myelopoiesis characterized by the production of myeloid-derived suppressor cells (MDSCs) and a deficiency in antigen-presenting cell function. We previously showed that a novel immune modulator, termed 'very small size particle' (VSSP), attenuates MDSC function in tumor-bearing mice, which was accompanied by an increase in dendritic cells (DCs) suggesting that VSSP exhibits myeloid differentiating properties. Therefore, here, we addressed two unresolved aspects of the mechanism of action of this unique immunomodulatory agent: (1) does VSSP alter myelopoiesis in the bone marrow to redirect MDSC differentiation toward a monocyte/macrophage or DC fate? and (2) does VSSP mitigate the frequency and suppressive function of human tumor-induced MDSCs?

METHODS

To address the first question, we first used a murine model of granulocyte-colony stimulating factor-driven emergency myelopoiesis following chemotherapy-induced myeloablation, which skews myeloid output toward MDSCs, especially the polymorphonuclear (PMN)-MDSC subset. Following VSSP treatment, progenitors and their myeloid progeny were analyzed by immunophenotyping and MDSC function was evaluated by suppression assays. To strengthen rigor, we validated our findings in tumor-bearing mouse models. To address the second question, we conducted a clinical trial in patients with metastatic renal cell carcinoma, wherein 15 patients were treated with VSSP. Endpoints in this study included safety and impact on PMN-MDSC frequency and function.

RESULTS

We demonstrated that VSSP diminished PMN-MDSCs by shunting granulocyte-monocyte progenitor differentiation toward monocytes/macrophages and DCs with heightened expression of the myeloid-dependent transcription factors interferon regulatory factor-8 and PU.1. This skewing was at the expense of expansion of granulocytic progenitors and rendered the remaining MDSCs less suppressive. Importantly, these effects were also demonstrated in a clinical setting wherein VSSP monotherapy significantly reduced circulating PMN-MDSCs, and their suppressive function.

CONCLUSIONS

Altogether, these data revealed VSSP as a novel regulator of myeloid biology that mitigates MDSCs in cancer patients and reinstates a more normal myeloid phenotype that potentially favors immune activation over immune suppression.

G-CSF in tumors: Aggressiveness, tumor microenvironment and immune cell regulation

Granulocyte colony-stimulating factor (G-CSF) is a cytokine most well-known for maturation and mobilization of bone marrow neutrophils. Although it is used therapeutically to treat chemotherapy induced neutropenia, it is also highly expressed in some tumors. Case reports suggest that tumors expressing high levels of G-CSF are aggressive, more difficult to treat, and present with poor prognosis and high mortality rates. Research on this topic suggests that G-CSF has tumor-promoting effects on both tumor cells and the tumor microenvironment. G-CSF has a direct effect on tumor cells to promote tumor stem cell longevity and overall tumor cell proliferation and migration. Additionally, it may promote pro-tumorigenic immune cell phenotypes such as M2 macrophages, myeloid-derived suppressor cells, and regulatory T cells. Overall, the literature suggests a plethora of pro-tumorigenic activity that should be balanced with the therapeutic use. In this review, we present an overview of the multiple complex roles of G-CSF and G-CSFR in tumors and their microenvironment and discuss how clinical advances and strategies may open new therapeutic avenues.

Aggressive Recurrent Pancreatic Cancer Producing Granulocyte Colony-Stimulating Factor

Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein which stimulates the proliferation, differentiation, and functional activation of myeloid hematopoietic cells. G-CSF-producing pancreatic cancer is rare and its prognosis is strikingly poor. A 69-year-old woman with well-to-moderately differentiated ductal adenocarcinoma (pT3N0M0, stage IIA) underwent distal pancreatectomy and splenectomy. Postoperative adjuvant chemotherapy with S-1 was administered for 6 months. Eleven months after surgery, periodic blood examination revealed remarkable leukocytosis (19,120/µL) without fever, which worsened 3 weeks later (36,160/µL). Furthermore, laboratory data showed elevation of the fibrin degradation product-D dimer and that the G-CSF level was high (406 pg/mL), as well as thrombopenia. Multiple liver and lung metastases were detected by contrast-enhanced computed tomography (CT). The patient was treated with gemcitabine plus nab-paclitaxel, and heparin, thrombomodulin alfa, and platelet transfusion were administered concurrently. Leukocytosis and thrombopenia were alleviated after 1 course of chemotherapy. However, remarkable leukocytosis (53,480/µL) recurred on day 1 of the third course of chemotherapy. Contrast-enhanced CT showed a significantly increased number of liver metastases and lung metastases. The patient chose not to receive second-line chemotherapy and died 1 month later at the affiliated hospital. Pancreatic cancer producing G-CSF shows very aggressive behavior. Leukocytosis without infection during routine observation should be considered as a warning of a rapidly growing recurrence.

An Attempt to Polarize Human Neutrophils Toward N1 and N2 Phenotypes in vitro

Neutrophils act as the first line of defense against invading pathogens. Although traditionally considered in context of their antimicrobial effector functions, the importance of tumor-associated neutrophils (TANs) in the development of cancer has become increasingly clear during the last decade. With regard to their high plasticity, neutrophils were shown to acquire an anti-tumorigenic N1 or a pro-tumorigenic N2 phenotype. Despite the urgent need to get a comprehensive understanding of the interaction of TANs with their tumor microenvironment, most studies still rely on murine tumor models. Here we present for the first time a polarization attempt to generate N1 and N2 neutrophils from primary human neutrophils in vitro. Our results underscore that N1-polarized neutrophils have a pro-inflammatory phenotype characterized among others by a higher level of intercellular adhesion molecule (ICAM)-1 and high secretion of interferon (IFN)γ-induced protein 10 (IP-10)/C-X-C motif chemokine 10 (CXCL10) and tumor necrosis factor (TNF). Further, we demonstrate that neutrophils incubated under a tumor-mimicking in vitro environment show a high cell surface expression of C-X-C motif chemokine receptor 2 (CXCR2) and secrete high levels of interleukin (IL)-8. These findings suggest that it is feasible to polarize blood-derived primary human neutrophils toward N1- and N2-like phenotypes in vitro. Further, we hypothesized that the presence of anti-inflammatory neutrophil phenotype is not a phenomenon limited to cancer but also occurs when neutrophils are infected with intracellular pathogens. Indeed, our findings indicate that N2-polarized neutrophils exert a markedly decreased capacity to kill the protozoan parasite Leishmania donovani and therefore permit parasite persistence.

The Role of ERO1α in Modulating Cancer Progression and Immune Escape

Endoplasmic reticulum oxidoreductin-1 alpha (ERO1α) was originally shown to be an endoplasmic reticulum (ER) resident protein undergoing oxidative cycles in concert with protein disulfide isomerase (PDI) to promote proper protein folding and to maintain homeostasis within the ER. ERO1α belongs to the flavoprotein family containing a flavin adenine dinucleotide utilized in transferring of electrons during oxidation-reduction cycles. This family is used to maintain redox potentials and protein homeostasis within the ER. ERO1α's location and function has since been shown to exist beyond the ER. Originally thought to exist solely in the ER, it has since been found to exist in the golgi apparatus, as well as in exosomes purified from patient samples. Besides aiding in protein folding of transmembrane and secretory proteins in conjunction with PDI, ERO1α is also known for formation of de novo disulfide bridges. Public databases, such as the Cancer Genome Atlas (TCGA) and The Protein Atlas, reveal ERO1α as a poor prognostic marker in multiple disease settings. Recent evidence indicates that ERO1α expression in tumor cells is a critical determinant of metastasis. However, the impact of increased ERO1α expression in tumor cells extends into the tumor microenvironment. Secretory proteins requiring ERO1α expression for proper folding have been implicated as being involved in immune escape through promotion of upregulation of programmed death ligand-1 (PD-L1) and stimulation of polymorphonuclear myeloid derived suppressor cells (PMN-MDSC's) via secretion of granulocytic colony stimulating factor (G-CSF). Hereby, ERO1α plays a pivotal role in cancer progression and potentially immune escape; making ERO1α an emerging attractive putative target for the treatment of cancer.

An autopsy case of granulocyte colony-stimulating factor-producing pancreatic adenosquamous carcinoma

A 60-year-old female was admitted to hospital with a continuous fever, a decreased appetite, and abdominal pain. Laboratory tests showed an elevated peripheral leukocyte count (13,800/μl) and increased C-reactive protein (19.1 mg/dl) and carbohydrate antigen 19-9 (4057 U/ml) levels. Abdominal contrast-enhanced computed tomography showed multiple bulky hypovascular nodules in the liver, swelling of the paraaortic lymph nodes, and a hypovascular mass (diameter 3.0 cm) in the pancreatic body. The serum concentrations of granulocyte colony-stimulating factor (G-CSF) and interleukin-6 were 172 pg/μl and 541 pg/µl, respectively. Liver biopsy specimens revealed an adenosquamous carcinoma, which was positively immunostained for G-CSF. We diagnosed the patient with G-CSF-producing pancreatic cancer with multiple metastases. Four courses of gemcitabine with dexamethasone and one course of nab-paclitaxel and gemcitabine were administered. Although the pancreatic tumor and paraaortic lymph node metastases decreased in size, the liver metastases continued to grow. The patient died 4 months after the diagnosis of pancreatic cancer. An autopsy resulted in the tumor being diagnosed as poorly differentiated adenosquamous pancreatic carcinoma, which was histopathologically G-CSF-positive. Although G-CSF-producing pancreatic adenosquamous carcinomas are extremely rare, they have been encountered more frequently in recent years. In such cases, chemotherapy combined with dexamethasone might be effective at temporarily improving the patient's condition.

Cancer-induced systemic myeloid dysfunction: Implications for treatment and a novel nanoparticle approach for its correction

Unlike other regulatory circuits, cancer-induced myeloid dysfunction involves more than an accumulation of impaired dendritic cells, protumoral macrophages, and myeloid derived suppressor cells in the tumor microenvironment. It is also characterized by "aberrant" myelopoiesis that results in the accumulation and expansion of immature myeloid precursors with a suppressive phenotype in the systemic circulation. The first part of this review briefly describes the evidence for and consequences of this systemic dysfunctional myelopoiesis and the possible reinforcement of this phenomenon by conventional treatments used in patients with cancer, in particular chemotherapy and granulocyte-colony stimulating factor. The second half of this review describes very small size particles, a novel immune-modulatory nanoparticle, and the evidence indicating a possible role of this agent in correcting or re-programming the dysfunctional myelopoiesis in different scenarios.

Relevance of Interferon Regulatory Factor-8 Expression in Myeloid-Tumor Interactions

Perturbations in myelopoiesis are a common feature in solid tumor biology, reflecting the central premise that cancer is not only a localized affliction but also a systemic disease. Because the myeloid compartment is essential for the induction of adaptive immunity, these alterations in myeloid development contribute to the failure of the host to effectively manage tumor progression. These "dysfunctional" myeloid cells have been coined myeloid-derived suppressor cells (MDSCs). Interestingly, such cells not only arise in neoplasia but also are associated with many other inflammatory or pathologic conditions. MDSCs affect disease outcome through multiple mechanisms, including their ability to mediate generalized or antigen-specific immune suppression. Consequently, MDSCs pose a significant barrier to effective immunotherapy in multiple disease settings. Although much interest has been devoted to unraveling mechanisms by which MDSCs mediate immune suppression, a large gap has remained in our understanding of the mechanisms that drive their development in the first place. Investigations into this question have identified an unrecognized role of interferon regulatory factor-8 (IRF-8), a member of the IRF family of transcription factors, in tumor-induced myeloid dysfunction. Ordinarily, IRF-8 is involved in diverse stages of myelopoiesis, namely differentiation and lineage commitment toward monocytes, dendritic cells, and granulocytes. Several recent studies now support the hypothesis that IRF-8 functions as a "master" negative regulator of MDSC formation in vivo. This review focuses on IRF-8 as a potential target suppressed by tumors to cripple normal myelopoiesis, redirecting myeloid differentiation toward the emergence of MDSCs. Understanding the bases by which neoplasia drives MDSC accumulation has the potential to improve the efficacy of therapies that require a competent myeloid compartment.

Granulocyte-colony stimulating factor producing mucinous cystic neoplasm with an associated invasive carcinoma of the pancreas

The present case study documents an autopsy case of granulocyte-colony stimulating factor (G-CSF)-producing mucinous cystic neoplasm (MCN), with an associated invasive carcinoma of the pancreas. A 65-year-old woman presented to Omuta City Hospital (Omuta Japan) with a primary complaint of abdominal pain. Multiple liver nodules and a pancreatic cyst were detected upon abdominal computed tomography. Initially, liver abscess was suspected as the patient exhibited leukocytosis and elevated C-reactive protein level. However, the serum concentration of G-CSF was 98.8 pg/ml (normal, <39.0 pg/ml). At 6 weeks after admission, the patient succumbed to liver failure. At autopsy, a cystic lesion was identified in the pancreatic tail that contained bloody necrotic fluid. Microscopically, the cystic lesion was composed of columnar and mucin-producing epithelium associated with ovarian-type subepithelial stroma. The stroma exhibited positive immunostaining for vimentin, estrogen receptor and progesterone receptor. Calcification on the cystic wall was observed. The tumor invaded the pancreatic parenchyma and metastasized to the liver and lungs. The lesion was diagnosed as invasive adenocarcinoma arising in MCN. By contrast, liver nodules predominantly consisted of pleomorphic cancer cells with small foci of adenocarcinoma. Pancreatic and hepatic cancer cells were confirmed to be positive for G-CSF staining. The present case report indicates that G-CSF-producing MCNs may be associated with an aggressive clinical course, particularly when anaplastic changes are observed.

Paraneoplastic Hyperleukocytosis in Pancreatic Adenocarcinoma

Background: Paraneoplastic hyperleukocytosis is a rare phenomenon observed in patients with adenocarcinomas and other malignancies. In this study, we present a case of paraneoplastic hyperleukocytosis in pancreatic adenocarcinoma secondary to excessive secretion of serum granulocyte colony-stimulating factor (G-CSF).

Presentation: We report a 71-year-old Caucasian male who presented to our hospital with hyperleukocytosis in the setting of locally advanced pancreatic adenocarcinoma. The patient was recently diagnosed 4 months before presentation and received abraxane/gemcitabine in addition to palliative radiation therapy for continued gastrointestinal bleeding. During routine laboratory assessment, the patient was found to have a white blood cell (WBC) count of 153 K/UL (75% neutrophils and 14% bands). Bone marrow biopsy and cytology were negative for neoplastic features. Serum G-CSF levels returned markedly elevated, supporting the diagnosis of paraneoplastic hyperleukocytosis. Interestingly, the WBC count decreased significantly following each of two cycles of chemotherapy, further suggesting a paraneoplastic etiology of hyperleukocytosis. The patient did not receive any growth factor support at any point before or during treatment.

Conclusion: In conclusion, the presence of hyperleukocytosis in cancer should raise clinical suspicion of a paraneoplastic phenomenon when other possible causes have been excluded. Hyperleukocytosis in this setting may correlate with progression of disease and lessen with treatment.

Case report of multiple pustules of the bilateral lower limbs caused by a granulocyte colony-stimulating factor-producing solid pseudopapillary tumour of the pancreas

Here we report a rare case of neutrophilic dermatoses related to a granulocyte colony-stimulating factor (G-CSF)-producing solid pseudopapillary tumour (SPT). The patient was a 39-year-old woman presenting with scattered pustules and crusts of the palms, heels and thighs and plaques of the bilateral lower legs. The skin biopsy revealed dense neutrophil infiltration in the epidermis to the dermis. A pancreatic head tumour was detected using computed tomography. A pathological examination of the resected specimen suggested an SPT. As the skin eruption promptly disappeared after SPT resection, we hypothesized that SPT secretes growth factors including epidermal growth factor (EGF) and G-CSF. The SPT cells stained positive for both EGF and G-CSF tumour cells. The serum levels of interleukin (IL)-6 and IL-10 and tumour necrosis factor-α were within normal limits before and after the SPT resection. In contrast, the serum IL-8, EGF and G-CSF levels decreased after the SPT resection. This is a rare case of neutrophilic dermatoses related to a G-CSF-producing SPT. The present case suggests that physicians should be aware that a G-CSF-producing tumour is a differential diagnosis to consider in patients with unusual aseptic pustulosis.

Neutrophils Suppress Intraluminal NK Cell-Mediated Tumor Cell Clearance and Enhance Extravasation of Disseminated Carcinoma Cells

Immune cells promote the initial metastatic dissemination of carcinoma cells from primary tumors. In contrast to their well-studied functions in the initial stages of metastasis, the specific roles of immunocytes in facilitating progression through the critical later steps of the invasion-metastasis cascade remain poorly understood. Here, we define novel functions of neutrophils in promoting intraluminal survival and extravasation at sites of metastatic dissemination. We show that CD11b(+)/Ly6G(+) neutrophils enhance metastasis formation via two distinct mechanisms. First, neutrophils inhibit natural killer cell function, which leads to a significant increase in the intraluminal survival time of tumor cells. Thereafter, neutrophils operate to facilitate extravasation of tumor cells through the secretion of IL1β and matrix metalloproteinases. These results identify neutrophils as key regulators of intraluminal survival and extravasation through their cross-talk with host cells and disseminating carcinoma cells.

SIGNIFICANCE

This study provides important insights into the systemic contributions of neutrophils to cancer metastasis by identifying how neutrophils facilitate intermediate steps of the invasion-metastasis cascade. We demonstrate that neutrophils suppress natural killer cell activity and increase extravasation of tumor cells. Cancer Discov; 6(6); 630-49. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 561.

Priming of neutrophils toward NETosis promotes tumor growth

Neutrophils play a major role in cancer biology and both pro- and antitumoral functions of tumor-infiltrating neutrophils have been described. We have shown that tumors, by releasing G-CSF into the bloodstream, prime circulating neutrophils to form neutrophil extracellular traps (NETs) and we have detected the presence of NETs within the tumor microenvironment. Here, we report, using PAD4-deficient mice with a defect in neutrophil chromatin decondensation and NET formation, that the priming of neutrophils toward NETosis favors tumor growth. Interestingly, in a tumor model that does not release G-CSF and in which neutrophils are not primed for NETosis, PAD4-deficiency did not reduce tumor growth. However, supplying exogenous G-CSF to the wild-type (WT) host promoted intratumoral NETosis and tumor growth. Taken together, our results suggest that the priming of neutrophils for NETosis by the tumor or its environment leads to the accumulation of intratumoral NETs and a growth advantage to the tumor. Our work unveiled a pro-tumoral role for NETs which strengthens their potential as a new target in the fight against cancer.

The prothrombotic activity of cancer cells in the circulation

The hemostatic system is often subverted in patients with cancer, resulting in life-threatening venous thrombotic events. Despite the multifactorial and complex etiology of cancer-associated thrombosis, changes in the expression and activity of cancer-derived tissue factor (TF) - the principle initiator of the coagulation cascade - are considered key to malignant hypercoagulopathy and to the pathophysiology of thrombosis. However, many of the molecular and cellular mechanisms coupling the hemostatic degeneration to malignancy remain largely uncharacterized. In this review we discuss some of the tumor-intrinsic and tumor-extrinsic mechanisms that may contribute to the prothrombotic state of cancer, and we bring into focus the potential for circulating tumor cells (CTCs) in advancing our understanding of the field. We also summarize the current status of anti-coagulant therapy for the treatment of thrombosis in patients with cancer.

LPS-Induced G-CSF Expression in Macrophages Is Mediated by ERK2, but Not ERK1

Granulocyte colony-stimulating factor (G-CSF) selectively stimulates proliferation and differentiation of neutrophil progenitors which play important roles in host defense against infectious agents. However, persistent G-CSF production often leads to neutrophilia and excessive inflammatory reactions. There is therefore a need to understand the mechanism regulating G-CSF expression. In this study, we showed that U0126, a MEK1/2 inhibitor, decreases lipopolysaccharide (LPS)-stimulated G-CSF promoter activity, mRNA expression and protein secretion. Using short hairpin RNA knockdown, we demonstrated that ERK2, and not ERK1, involves in LPS-induced G-CSF expression, but not LPS-regulated expression of TNF-α. Reporter assays showed that ERK2 and C/EBPβ synergistically activate G-CSF promoter activity. Further chromatin immunoprecipitation (ChIP) assays revealed that U0126 inhibits LPS-induced binding of NF-κB (p50/p65) and C/EBPβ to the G-CSF promoter, but not their nuclear protein levels. Knockdown of ERK2 inhibits LPS-induced accessibility of the G-CSF promoter region to DNase I, suggesting that chromatin remodeling may occur. These findings clarify that ERK2, rather than ERK1, mediates LPS-induced G-CSF expression in macrophages by remodeling chromatin, and stimulates C/EBPβ-dependent activation of the G-CSF promoter. This study provides a potential target for regulating G-CSF expression.

Granulocyte-colony stimulating factor producing anaplastic carcinoma of the pancreas treated by distal pancreatectomy and chemotherapy: report of a case

Granulocyte-colony stimulating factor (G-CSF) producing pancreatic cancers are extremely rare. These tumors have an aggressive clinical course but no established treatment. We encountered a patient with a G-CSF-induced pancreatic cancer who was treated by surgical resection, followed by steroid treatment and chemotherapy. A 68-year-old Asian male presented at a local hospital with a 3-month history of fever, loss of appetite, and 10-kg weight loss. Laboratory data showed leukocytosis and elevation of C-reactive protein. Computed tomography (CT) revealed a 50-mm mass in the tail of the pancreas, but no signs of infective foci. He was transferred to our hospital for further evaluation. Contrast-enhanced CT showed rapid growth of this tumor over 1 week, and ¹⁸ F-2-fluoro-2-deoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) showed FDG accumulation in the tail of the pancreas (SUV max, 17.1) but at no other sites in his body. Magnetic resonance imaging showed a heterogeneous mass, similar to that observed by CT. Three weeks later, the patient underwent a distal pancreatectomy with splenectomy. The resected specimen was 154 mm in diameter, a threefold increase from the initial image. Histopathological examination identified the tumor as an anaplastic carcinoma of the pancreas. Following surgery, his leukocyte count and body temperature were reduced. He recovered well and was discharged from our hospital on postoperative day 18. Immunohistochemical expression of G-CSF in the resected specimen and elevated serum G-CSF concentration confirmed that the mass was a G-CSF producing anaplastic carcinoma of the pancreas. Subsequently, the patient experienced a high fever and loss of appetite. CT showed recurrence of cancer in the abdominal cavity, for which he was started immediately on tegafur-gimeracil-oteracil potassium combination S-1 and steroid. Unfortunately, he died on postoperative day 83. To our knowledge, this patient was the first with a G-CSF producing anaplastic carcinoma of the pancreas to be treated by surgical resection, steroid and adjuvant chemotherapy.

Cancer-associated oxidoreductase ERO1-α drives the production of tumor-promoting myeloid-derived suppressor cells via oxidative protein folding

Endoplasmic reticulum disulfide oxidase ERO1-α plays a role in the formation of disulfide bonds in collaboration with protein disulfide isomerase. Disulfide bond formation is required for the proper conformation and function of secreted and cell surface proteins. We found that ERO1-α was overexpressed in a variety of tumor types; therefore, we examined its role in tumor growth. In BALB/c mice, knockdown of ERO1-α within 4T1 mouse mammary gland cancer (KD) cells caused retardation of in vivo tumor growth compared with tumor growth of scrambled control (SCR) cells. In contrast, when ERO1-α-overexpressed 4T1 (OE) cells were compared with mock control cells, OE cells showed augmented tumor growth. However, differences in tumor growth were not observed among four groups of nude mice, suggesting that expression of ERO1-α diminished antitumor immunity. We observed dense peritumoral granulocytic infiltrates in tumors of wild-type 4T1 and SCR cells but not KD cells, and these cells were identified as polymorphonuclear myeloid-derived suppressor cells (MDSCs). In addition, production of G-CSF and CXCL1/2, which have intramolecular disulfide bonds, from KD cells was significantly decreased compared with that from SCR cells. In contrast, OE cells produced a larger amount of these molecules than did mock cells. These changes were regulated at the posttranscriptional level. These results suggest that overexpression of ERO1-α in the tumor inhibits the T cell response by recruiting polymorphonuclear MDSCs via regulation of MDSC-prone cytokines and chemokines.

The Multifaceted Roles Neutrophils Play in the Tumor Microenvironment

Neutrophils are myeloid cells that constitute 50-70 % of all white blood cells in the human circulation. Traditionally, neutrophils are viewed as the first line of defense against infections and as a major component of the inflammatory process. In addition, accumulating evidence suggest that neutrophils may also play a key role in multiple aspects of cancer biology. The possible involvement of neutrophils in cancer prevention and promotion was already suggested more than half a century ago, however, despite being the major component of the immune system, their contribution has often been overshadowed by other immune components such as lymphocytes and macrophages. Neutrophils seem to have conflicting functions in cancer and can be classified into anti-tumor (N1) and pro-tumor (N2) sub-populations. The aim of this review is to discuss the varying nature of neutrophil function in the cancer microenvironment with a specific emphasis on the mechanisms that regulate neutrophil mobilization, recruitment and activation.

NETosis: a new factor in tumor progression and cancer-associated thrombosis

Neutrophils have long been known as innate immune cells that phagocytose and kill pathogens and mount inflammatory responses protecting the host from infection. In the past decades, new aspects of neutrophils have emerged unmasking their importance not only in inflammation but also in many pathological conditions including thrombosis and cancer. The 2004 discovery that neutrophils, upon strong activation, release decondensed chromatin to form neutrophil extracellular traps (NETs), has unveiled new avenues of research. Here, we review current knowledge regarding NETs in thrombosis, with a special focus on cancer-associated thrombosis as well as their potential role in cancer growth and metastasis. We discuss the prospective use of NET-specific biomarkers, such as citrullinated histone H3 and NET inhibitors, as tools to anticipate and fight cancer-associated thrombosis. We propose that the rapid developments in the field of NETosis may provide new targets to combat the thrombotic consequences of cancer and perhaps even help to contain the disease itself.

Modulation of neutrophil granulocytes in the tumor microenvironment: mechanisms and consequences for tumor progression

Accumulating evidence indicates a critical role of myeloid cells in the pathophysiology of human cancers. In contrast to the well-characterized tumor-associated macrophages (TAMs), the significance of granulocytes in cancer has only recently begun to emerge. Increased numbers of neutrophil granulocytes have been observed both in the peripheral blood and in the tumor tissues of patients with different types of cancer. Importantly, these studies linked neutrophils to poor clinical outcome in cancer patients which suggests that these cells might have important tumor-promoting activities. Indeed, a number of functional in vitro and in vivo studies demonstrated that tumors stimulated neutrophils to promote angiogenesis and immunosuppression, as well as migration, invasion and metastasis of the tumor cells. Therefore, it became necessary to understand the mechanisms modulating the changes in the biology and functions of neutrophils in the context of the tumor microenvironment. In this review we will discuss several functions of neutrophils that might contribute to tumor progression. Furthermore, we will address in detail the cellular and molecular mechanisms that control modulation of neutrophils in the tumor microenvironment, such as recruitment to the tumor site (chemotaxis), prolonged survival and enhanced release of protumoral mediators.

Differentiating Branch Duct and Mixed IPMN in Endoscopically Collected Pancreatic Cyst Fluid via Cytokine Analysis

Background. Differentiating branch duct from mixed intraductal papillary mucinous neoplasm (BD-IPMN) is problematic, but clinically important as mixed IPMNs are managed surgically, while some BD-IPMN may be followed. Inflammatory mediator proteins (IMPs) have been implicated in acute and chronic inflammatory and malignant pancreatic diseases. Aim. To compare IMP profile of pancreatic cyst fluid collected endoscopically from BD-IPMN and mixed IPMN. Methods. Pancreatic cyst fluid from ten patients (5 BD-IPMN and 5 mixed IPMN) was collected by endoscopic ultrasound-guided fine needle aspiration or endoscopic retrograde cholangiopancreatography. Concentrations of 89 IMPs in these samples were determined using a multiplexed bead-based microarray protein assay and compared between BD-IPMN and mixed IPMN. Results. Eighty-six of 89 IMPs were detected in at least one of the 10 samples. Fourteen IMPs were detected only in mixed IPMN, while none were only in BD-IPMN. Of these, TGF-β1 was most prevalent, present in 3 of 5 mixed IPMNs. Seventy-two IMPs were detected in both BD-IPMN and mixed IPMNs. Of these, only G-CSF (P < 0.05) was present in higher concentrations in mixed IPMNs. Conclusion. TGF-β1 and G-CSF detected in endoscopically collected pancreatic cyst fluid are potential diagnostic biomarkers capable of distinguishing mixed IPMN from BD-IPMN.

Cancers predispose neutrophils to release extracellular DNA traps that contribute to cancer-associated thrombosis

Cancer-associated thrombosis often lacks a clear etiology. However, it is linked to a poor prognosis and represents the second-leading cause of death in cancer patients. Recent studies have shown that chromatin released into blood, through the generation of neutrophil extracellular traps (NETs), is procoagulant and prothrombotic. Using a murine model of chronic myelogenous leukemia, we show that malignant and nonmalignant neutrophils are more prone to NET formation. This increased sensitivity toward NET generation is also observed in mammary and lung carcinoma models, suggesting that cancers, through a systemic effect on the host, can induce an increase in peripheral blood neutrophils, which are predisposed to NET formation. In addition, in the late stages of the breast carcinoma model, NETosis occurs concomitant with the appearance of venous thrombi in the lung. Moreover, simulation of a minor systemic infection in tumor-bearing, but not control, mice results in the release of large quantities of chromatin and a prothrombotic state. The increase in neutrophil count and their priming is mediated by granulocyte colony-stimulating factor (G-CSF), which accumulates in the blood of tumor-bearing mice. The prothrombotic state in cancer can be reproduced by treating mice with G-CSF combined with low-dose LPS and leads to thrombocytopenia and microthrombosis. Taken together, our results identify extracellular chromatin released through NET formation as a cause for cancer-associated thrombosis and unveil a target in the effort to decrease the incidence of thrombosis in cancer patients.

Granulocyte colony-stimulating factor-producing squamous cell carcinoma of the lower gingiva: a case report

The present study summarizes our experience in treating a patient with a suspected granulocyte colony-stimulating factor (G-CSF)-producing squamous cell carcinoma (SCC) of the lower gingiva, which is a rather rare entity.

A 56-year-old woman underwent surgical excision of palate leukoplakia in 1996. In 2009, however, a leukoplakic superficial tumor was detected in the lower left gingiva, for which the patient underwent gingivectomy. This was subsequently diagnosed as SCC. The patient also underwent superselective arterial injection chemotherapy combined with radiotherapy, after local recurrence was observed. The patient was subsequently found to have bone metastasis. After chemotherapy combined with radiotherapy, the patient underwent segmental resection of the lower left jaw, left supraomohyoid neck dissection, and lower jaw reconstruction using titanium plates. Resection of the left femoral tumor and left total knee replacement were also performed. Computed tomography scan performed 1 month after the surgeries revealed multiple lung, liver, spine, and subcutaneous metastases. The patient also exhibited a sudden increase in her white blood cell (WBC) count and a fever that could not be alleviated, despite treatment with antibacterial drugs. A G-CSF-producing tumor was therefore suspected. Serum G-CSF level was high at 250 pg/ml.

The patient's WBC count increased to 32 × 10³/ml and her general condition suddenly deteriorated, and she died as a result of multiple organ failure. A final diagnosis of G-CSF-producing SCC of the lower gingiva was made based on the patient's clinical course.

Tumor-derived G-CSF facilitates neoplastic growth through a granulocytic myeloid-derived suppressor cell-dependent mechanism

Myeloid-derived suppressor cells (MDSC) are induced under diverse pathologic conditions, including neoplasia, and suppress innate and adaptive immunity. While the mechanisms by which MDSC mediate immunosuppression are well-characterized, details on how they develop remain less understood. This is complicated further by the fact that MDSC comprise multiple myeloid cell types, namely monocytes and granulocytes, reflecting diverse stages of differentiation and the proportion of these subpopulations vary among different neoplastic models. Thus, it is thought that the type and quantities of inflammatory mediators generated during neoplasia dictate the composition of the resultant MDSC response. Although much interest has been devoted to monocytic MDSC biology, a fundamental gap remains in our understanding of the derivation of granulocytic MDSC. In settings of heightened granulocytic MDSC responses, we hypothesized that inappropriate production of G-CSF is a key initiator of granulocytic MDSC accumulation. We observed abundant amounts of G-CSF in vivo, which correlated with robust granulocytic MDSC responses in multiple tumor models. Using G-CSF loss- and gain-of-function approaches, we demonstrated for the first time that: 1) abrogating G-CSF production significantly diminished granulocytic MDSC accumulation and tumor growth; 2) ectopically over-expressing G-CSF in G-CSF-negative tumors significantly augmented granulocytic MDSC accumulation and tumor growth; and 3) treatment of naïve healthy mice with recombinant G-CSF protein elicited granulocytic-like MDSC remarkably similar to those induced under tumor-bearing conditions. Collectively, we demonstrated that tumor-derived G-CSF enhances tumor growth through granulocytic MDSC-dependent mechanisms. These findings provide us with novel insights into MDSC subset development and potentially new biomarkers or targets for cancer therapy.

A Retroperitoneal Dedifferentiated Liposarcoma Producing Granulocyte Colony-Stimulating Factor Accompanied by Spontaneous Rupture: PET/CT Imaging of a G-CSF-Producing Tumor

The patient was a 63-year-old man who was referred to our hospital as an emergency case with the chief complaint of abdominal pain. An abdominal CT revealed a right retroperitoneal tumor of 15 cm and retroperitoneal bleeding. After a transcatheter arterial embolization was performed, the patient was transferred to our department. There was no infective focus. The white blood cell (WBC) count (37,820/μl, normal range <8 pg/ml) and the serum granulocyte colony-stimulating factor (G-CSF) level (2,670 pg/ml, normal range <8 pg/ml) were high. Bone marrow biopsy revealed little fat, significant hyperplasia, and predominantly increased neutrophils, but no findings of bone metastasis or bone marrow involvement. A G-CSF-producing tumor was diagnosed and right nephrectomy and retroperitoneal tumorectomy were performed. However, the tumor had infiltrated into the inferior vena cava, diaphragm and abdominal wall, and only part of the tumor could be removed. In histopathological tests, hematoxylin-eosin staining showed malignant fibrous histiocytoma-like findings mixed with those for well-differentiated liposarcoma, and the case was diagnosed as dedifferentiated liposarcoma. Preoperative (18)F-FDG-PET computed tomography showed diffuse (18)F-FDG uptake throughout the bone marrow and elevated uptake at the tumor site. However, since bone biopsy and bone scintigraphy indicated no bone metastasis or bone marrow involvement, we concluded that PET/CT imaging gave false-positive results in the bone marrow. This is the first report of PET/CT imaging of a G-CSF-producing tumor in a urological disease. The imaging results may be useful for differential diagnosis for this tumor in patients with high WBC counts without infection.

A Case of Ovarian Clear Cell Carcinoma Simultaneously Producing Parathyroid Hormone-related Protein and Granulocyte Colony-Stimulating Factor

We describe the first report of an ovarian clear cell carcinoma simultaneously producing parathyroid hormone-related protein (PTHrP) and granulocyte colony-stimulating factor (G-CSF). A 64-year-old woman complained of general fatigue, loss of appetite, nausea, vomiting and constipation. The results of blood and biochemistry tests were white blood cell count of 21,060 /ml and calcium of 18.0 mg/dl, indicating an increase in the number of leukocytes and hypercalcemia. A computerized tomography scan showed a tumor in the lower abdomen with a maximum diameter of 16 cm and containing both cystic and solid parts. There was a remarkable elevation of the tumor marker CA 19-9, to 1611 IU/ml, and serum level of PTHrP was elevated to 25.9 pmol/ml. The PTH-intact level was 14 pg/ml, which was at the lower limit of the normal range. In addition, the G-CSF level was also elevated to 73 pg/ml (normal range: <38 pg/ml). Since hypercalcemia caused by tumor PTHrP production was suspected, and as this required elimination of the primary disease, extirpation of the tumor was carried out. Serum calcium levels promptly returned to 11.1 mg/ml on the first day following surgery, and PTHrP also dropped to its normal level on the same day. Histological and immunohistochemical examinations revealed that the tumor was clear cell adenocarcinoma which was partially positive for PTHrP and positive for G-CSF, indicating the tumor simultaneously producing PTHrP and G-CSF.