Regulatory T-cells inhibit microglia-induced pain hypersensitivity in female mice.

Peripheral nerve injury-induced neuropathic pain is a chronic and debilitating condition characterized by mechanical hypersensitivity. We previously identified microglial activation via release of colony-stimulating factor 1 (CSF1) from injured sensory neurons as a mechanism contributing to nerve injury-induced pain. Here, we show that intrathecal administration of CSF1, even in the absence of injury, is sufficient to induce pain behavior, but only in male mice. Transcriptional profiling and morphologic analyses after intrathecal CSF1 showed robust immune activation in male but not female microglia. CSF1 also induced marked expansion of lymphocytes within the spinal cord meninges, with preferential expansion of regulatory T-cells (Tregs) in female mice. Consistent with the hypothesis that Tregs actively suppress microglial activation in females, Treg deficient (Foxp3DTR) female mice showed increased CSF1-induced microglial activation and pain hypersensitivity equivalent to males. We conclude that sexual dimorphism in the contribution of microglia to pain results from Treg-mediated suppression of microglial activation and pain hypersensitivity in female mice.

M-CSF and prostratin induced Mregs promote immune tolerance in transplanted mice through Arg-1 pathway.

OBJECTIVE: Regulatory macrophages (Mregs) are a group of heterogeneous macrophages. These cells could induce immunosuppressive effects through the expression of immune regulatory molecules and cytokines. METHODS: The differentiation of Mregs was induced by treating bone marrow cells with M-CSF and prostratin in vitro. The cell-phenotypes and immunosuppressive function were determined by flow cytometry. Rt-PCR was employed to assess the mechanisms of Mregs. Skin grafted mouse model was used for in vivo validation. RESULTS: Mregs induced by M-CSF + prostratin had a strong inhibitory effect on T cell proliferation and cytokines production. The phenotype of induced bone marrow cells changed towards Mregs. These Mregs could induce the differentiation of Tregs in vivo. Arg-1 expression in these cells were significantly upregulated. Inhibition of arginase (Arg) or arginine supplement significantly reversed the immunosuppressive function. In mice skin-grafted models, adoptive transfer of these Mregs significantly prolonged allograft survival. In mice models, Arg-1 expression significantly elevated on skin grafts cells and Tregs increased in graft tissues. CONCLUSIONS: We successfully developed a Mregs-inducing protocol with the combination of M-CSF and prostratin in vitro. M-CSF + prostratin induced Mregs prevented mice skin graft rejection through upregulating the expression Arg-1.

Dermal bacterial LPS-stimulation reduces susceptibility to intradermal Trypanosoma brucei infection.

Infections with Trypanosoma brucei sp. are established after the injection of metacyclic trypomastigotes into the skin dermis by the tsetse fly vector. The parasites then gain access to the local lymphatic vessels to infect the local draining lymph nodes and disseminate systemically via the bloodstream. Macrophages are considered to play an important role in host protection during the early stage of systemic trypanosome infections. Macrophages are abundant in the skin dermis, but relatively little is known of their impact on susceptibility to intradermal (ID) trypanosome infections. We show that although dermal injection of colony stimulating factor 1 (CSF1) increased the local abundance of macrophages in the skin, this did not affect susceptibility to ID T. brucei infection. However, bacterial LPS-stimulation in the dermis prior to ID trypanosome infection significantly reduced disease susceptibility. In vitro assays showed that LPS-stimulated macrophage-like RAW264.7 cells had enhanced cytotoxicity towards T. brucei, implying that dermal LPS-treatment may similarly enhance the ability of dermal macrophages to eliminate ID injected T. brucei parasites in the skin. A thorough understanding of the factors that reduce susceptibility to ID injected T. brucei infections may lead to the development of novel strategies to help reduce the transmission of African trypanosomes.

Association of miltefosine with granulocyte and macrophage colony-stimulating factor (GM-CSF) in the treatment of cutaneous leishmaniasis in the Amazon region: A randomized and controlled trial.

OBJECTIVES: To compare topical granulocyte and macrophage colony-stimulating factor (GM-CSF) and miltefosine (G + M) versus placebo and miltefosine (P + M) or parenteral meglumine antimoniate (MA) in the treatment of 150 patients with cutaneous leishmaniasis (CL) caused by Leishmania guyanensis in the Amazon. DESIGN: A randomized and double-blinded clinical trial. RESULTS: At 90 days after the initiation of therapy, the cure rates were 66%, 58%, and 52% for the groups P + M, G + M, and MA, respectively (p > 0.05). Cure rates at 180 days did not differ. Healing time was similar in the 3 groups, but faster in the MA group as compared to the G + M group (p = 0.04). Mild and transitory systemic adverse events were frequent in all groups (above 85%). Nausea (85%) and vomiting (39%) predominated in the miltefosine groups and arthralgia (51%) and myalgia (48%) in the MA group. One patient (group MA) stopped treatment after presenting with fever, exanthema, and severe arthralgia. CONCLUSIONS: Miltefosine did not present a higher cure rate than MA, and the association of GM-CSF did not improve the therapeutic response. Nevertheless, because of its less toxicity, easier administration, and a similar cure rate when compared with MA, miltefosine should remain as one of the main drugs for treating CL due to L. guyanensis. (Clinicaltrials.gov Identifier NCT03023111).

The AMPK pathway triggers autophagy during CSF1-induced microglial activation and may be implicated in inducing neuropathic pain.

The development and maintenance of neuropathic pain is now given far more attention in the clinic work. Increasing evidence has shown that colony-stimulating factor 1 (CSF1) is involved in microglial activation and may further induce pain. Here, we observed the signaling events that link the CSF1-induced microglial activated and consequences for pain processing. For the in vitro study, flow cytometry showed the microglial activity was markedly increased after CSF1 stimulation. Western blot showed the increased expression of p-PRKAA1/PRKAA1, p-AMPK/AMPK, p-ULK1/ULK1, p-S6k/S6k and LC3-II/LC3-I. QRT-PCR showed the IL-1, TNF-α and BDNF were simultaneously upregulated in the activated microglia cells, whereas the specific AMPK inhibitor compound C exhibited reverse effects in microglia. Using immunofluorescence staining and electron microscopy, we found CSF1 decreased microglial p62 expression and induced the number of autophagosomes, whereas compound C significantly exhibited the reverse effects. For the in vivo study, compared with the control and AMPK-siRNA transfection, the mice under CSF1 intrathecal injection increased CSF1 receptor and LC3 expressed in the activated spinal microglia. More importantly, qRT-PCR showed CSF1 intrathecal injection substantially upregulated BDNF and c-Fos mRNA expression as well as the ensuing neuropathic pain. Our findings demonstrated that CSF1 induced a significant upregulation of microglial activation via the AMPK signaling pathway and resulted in an increasing microglial autophagic level. An increasing CSF1 level in the central nervous system can mimic and cause pain syndromes by up-regulation of AMPK-depended autophagy, thus offering a new target for the therapy of neuropathic pain.

Analysis of the impact of CSF-1 administration in adult rats using a novel Csf1r-mApple reporter gene.

Macrophages are present in large numbers in every tissue in the body where they play critical roles in development and homeostasis. They exhibit remarkable phenotypic and functional diversity, underpinning their adaptation to specialized roles in each tissue niche. CSF1, signaling through the CSF1 receptor, which is restricted to monocyte-macrophage lineage cells in adults, is a critical growth factor controlling macrophage proliferation, differentiation, and many aspects of mature macrophage function. We have generated a macrophage reporter rat, utilizing a construct containing elements of the mouse Csf1r promoter and the highly conserved Fms intronic regulatory element to drive mApple fluorescent protein expression. Csf1r-mApple was robustly expressed in monocyte-macrophage lineage cells in rat bone marrow (BM), peripheral blood, and tissues, with detectable expression in granulocytes and B cells and no evidence of expression in hematopoietic precursors or non-hematopoietic cells. Here, we use the Csf1r-mApple transgene to highlight and dissect the abundance and heterogeneity of rat tissue macrophage populations, and to demonstrate parallel increases in blood monocytes and multiple tissue macrophage populations, including BM, liver, spleen, and lung, in response to CSF1 treatment in vivo. The Csf1r-mApple rat is a novel tool enabling analysis of rat macrophages in situ by direct imaging and providing an additional phenotypic marker to facilitate exploration of rat tissue macrophage phenotypic and functional heterogeneity.

Evaluation of pro­ and anti­tumor effects induced by three colony­stimulating factors, G­CSF, GM­CSF and M­CSF, in bladder cancer cells: Is G­CSF a friend of bladder cancer cells?

Cytotoxic chemotherapy is the standard treatment for patients with advanced bladder cancer. However, this treatment can cause transient and prolonged neutropenia, which can result in fatal infection. Three recombinant human colony­stimulating factors (CSFs), granulocyte CSF (G­CSF), granulocyte­macrophage CSF (GM­CSF), and macrophage CSF (M­CSF), are currently available to reduce the duration and degree of neutropenia. The present study investigated the pro­ and anti­tumor effects of these three CSFs and the changes in molecular profiles. Xenograft tumors in athymic mice were generated by subcutaneously inoculating the human bladder cancer cell lines MGH­U3 and UM­UC­3. A total of 2 weeks after cell inoculation, mice were randomly divided into four groups (control, G­CSF, GM­CSF and M­CSF) and treated thrice a week for 2 weeks. Tumor growth during monitoring and tumor weight at the time of euthanization were significantly higher in mice treated with G­CSF and lower in mice treated with GM­CSF compared with the control mice. Tumors were examined by immunostaining with antibodies against proteins associated tumor proliferation (Ki­67), angiogenesis [CD31 and vascular endothelial growth factor (VEGF)], anti­immunity (CD204) and epithelial­mesenchymal transition (EMT; E­cadherin). Immunohistochemical staining revealed that tumor proliferation, angiogenesis, recruitment of M2 macrophages and EMT were promoted by G­CSF, whereas lymphangiogenesis and recruitment of M2 macrophages were inhibited by GM­CSF. Treatment­associated changes in serum pro­ and anti­tumoral cytokines and chemokines were evaluated by enzyme­linked immunosorbent assay (ELISA)­based arrays. In the ELISA for serum, the levels of cytokines associated with angiogenesis (interleukin­6 and VEGF), and EMT (transforming growth factor­ß1 and ­ß2) were elevated in mice treated with G­CSF. Treatment with GM­CSF and M­CSF also affected the level of these cytokines characteristically. The current results indicate that administration of exogenous G­CSF to patients with bladder cancer promotes tumor growth through promotion of cell proliferation, angiogenesis, recruitment of M2 macrophages and enhancement of EMT through the modulation of the tumor microenvironment.

Macrophage colony-stimulating factor pretreatment of bone marrow progenitor cells regulates osteoclast differentiation based upon the stage of myeloid development.

Osteoclasts (OCs) are large, multinucleated bone resorbing cells originating from the bone marrow myeloid lineage, and share a common progenitor with macrophages and dendritic cells. Bone marrow cells (BMCs) are a common source for in vitro osteoclastogenesis assays but are a highly heterogeneous mixture of cells. Protocols for in vitro osteoclastogenesis vary considerably thus hindering interpretation and comparison of results between studies. Macrophage colony-stimulating factor (M-CSF) pretreatment is commonly used to expand OC progenitors (OCPs) in BMC cultures before in vitro differentiation. However, the failure of osteoclastogenesis of M-CSF primed bone marrow myeloid blasts has been reported. In this study, we used a simple method of differential adherence to plastic to enrich OCP from mouse BMCs. We found that M-CSF pretreatment of plastic-adherent BMCs (adBMCs) increased the number of CD11b-F4/80+ macrophages and decreased the number of CD11b+ monocytes resulting in decreased OC formation. M-CSF pretreatment of purified c-Kit+ progenitors weakly inhibited OC formation, whereas M-CSF pretreatment of purified c-Kit-CD11b+ progenitors promoted the formation of large OC. M-CSF pretreatment increased the proliferation of both purified c-Kit+ and c-Kit-CD11b+ cells and increased the percentage of CD11b-F4/80+ cells from c-Kit+ progenitors. In addition, M-CSF pretreatment increased the percentage of CD11b+ F4/80- cells from purified c-Kit-CD11b+ cells. M-CSF pretreatment increased the percentage of CD14 + CD16 + intermediate monocytes and subsequent OC formation from human 2adBMCs, and increased OC formation of purified CD14 + cells. Together, these results indicate that in vitro OCP expansion in the presence of M-CSF and bone marrow stromal cells is dependent upon the developmental stage of myeloid cells, in which M-CSF favors macrophage differentiation of multipotent progenitors, promotes monocyte maturation and supports differentiation of late-stage OCP cells.

Accelerating skin wound healing by M-CSF through generating SSEA-1 and -3 stem cells in the injured sites.

Wound healing is a complicated process requiring the collaborative efforts of different cell lineages. Our recent studies have found that one subset of hematopoietic cells can be induced to dedifferentiate into multipotent stem cells by means of a proliferating fibroblast releasable factor, M-CSF. Understanding the importance of stem cells on skin wound healing, here we evaluate the biological significance of M-CSF on skin wound healing. In an in vivo mouse skin excisional wound model, we found that SSEA-positive stem cells were present in wounded but not normal skin. After isolating skin cells from either normal or wounded skin by collagenase digestion, and analyzing the SSEA-1 positive cells by flow cytometry, we found a significant increase in the number of SSEA-1 positive cells in wounded skin. Topical application of M-CSF in skin wounds accelerated healing remarkably, while application of M-CSF-neutralizing antibody slowed wound healing. Furthermore, injection of EGFP-labeled hematopoietic cell-derived stem cells generated from M-CSF treated splenocytes resulted in EGFP-labeled cells being enriched in the skin wound site and further differentiated into functional organ-specific cells. Together, these data demonstrated that M-CSF makes a significant contribution to the healing process by inducing hematopoietic cell dedifferentiation into stem cells.

Results from a Phase IIA Parallel Group Study of JNJ-40346527, an Oral CSF-1R Inhibitor, in Patients with Active Rheumatoid Arthritis despite Disease-modifying Antirheumatic Drug Therapy.

OBJECTIVE: To assess the efficacy and safety of JNJ-40346527, a selective inhibitor of colony-stimulating factor-1 (CSF-1) receptor kinase that acts to inhibit macrophage survival, proliferation, and differentiation in patients with active rheumatoid arthritis (RA) despite disease-modifying antirheumatic drug (DMARD) therapy. METHODS: In this randomized, double-blind, placebo-controlled, parallel group study, adults were randomized (2:1) to receive oral JNJ-40346527 100 mg or placebo twice daily through Week 12. Patients with RA had disease activity [≥ 6 swollen/≥ 6 tender joints, C-reactive protein (CRP) ≥ 0.8 mg/dl] despite DMARD therapy for ≥ 6 months. The primary endpoint was change from baseline at Week 12 in the 28-joint Disease Activity Score with CRP (DAS28-CRP). Pharmacokinetic/pharmacodynamic analyses were also performed, and safety was assessed through Week 16. RESULTS: Ninety-five patients were treated (63 JNJ-40346527, 32 placebo); 8 patients discontinued treatment (6 JNJ-40346527, 2 placebo) through Week 12. Mean improvements in DAS28-CRP from baseline to Week 12 were 1.15 for the JNJ-40346527 group and 1.42 for the placebo group (p = 0.30); thus, a statistically significant difference was not observed for the primary endpoint. Pharmacokinetic exposure to JNJ-40346527 and its active metabolites was above the projected concentration needed for pharmacologic activity, and effective target engagement and proof of activity were demonstrated by increased levels of CSF-1 and decreased CD16+ monocytes in JNJ-40346527-treated, but not placebo-treated, patients. Thirty-seven (58.7%) JNJ-40346527-treated and 16 (50.0%) placebo-treated patients reported ≥ 1 adverse event (AE); 1 (1.6%) JNJ-40346527-treated and 3 (9.4%) placebo-treated patients reported ≥ 1 serious AE. CONCLUSION: Although adequate exposure and effective peripheral target engagement were evident, JNJ-40346527 efficacy was not observed in patients with DMARD-refractory active RA. ClinicalTrials.gov identifier: NCT01597739. EudraCT Number: 2011-004529-28.

MafB antagonizes phenotypic alteration induced by GM-CSF in microglia.

Microglia are tissue-resident macrophages which are distributed throughout the central nervous system (CNS). Recent studies suggest that microglia are a unique myeloid population distinct from peripheral macrophages in terms of origin and gene expression signature. Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic cytokine regulating myeloid development, has been shown to stimulate proliferation and alter phenotype of microglia in vitro. However, how its signaling is modulated in microglia is poorly characterized. MafB, a bZip transcriptional factor, is highly expressed in monocyte-macrophage lineage cells including microglia, although its role in microglia is largely unknown. We investigated the crosstalk between GM-CSF signaling and MafB by analyzing primary microglia. We found that Mafb-deficient microglia grew more rapidly than wild-type microglia in response to GM-CSF. Moreover, the expression of genes associated with microglial differentiation was more downregulated in Mafb-deficient microglia cultured with GM-CSF. Notably, such differences between the genotypes were not observed in the presence of M-CSF. In addition, we found that Mafb-deficient microglia cultured with GM-CSF barely extended their membrane protrusions, probably due to abnormal activation of RhoA, a key regulator of cytoskeletal remodeling. Altogether, our study reveals that MafB is a negative regulator of GM-CSF signaling in microglia. These findings could provide new insight into the modulation of cytokine signaling by transcription factors in microglia.

The effect of CSF-1 administration on lung maturation in a mouse model of neonatal hyperoxia exposure.

BACKGROUND: Lung immaturity due to preterm birth is a significant complication affecting neonatal health. Despite the detrimental effects of supplemental oxygen on alveolar formation, it remains an important treatment for infants with respiratory distress. Macrophages are traditionally associated with the propagation of inflammatory insults, however increased appreciation of their diversity has revealed essential functions in development and regeneration. METHODS: Macrophage regulatory cytokine Colony-Stimulating Factor-1 (CSF-1) was investigated in a model of neonatal hyperoxia exposure, with the aim of promoting macrophages associated with alveologenesis to protect/rescue lung development and function. Neonatal mice were exposed to normoxia (21% oxygen) or hyperoxia (Hyp; 65% oxygen); and administered CSF-1 (0.5 µg/g, daily × 5) or vehicle (PBS) in two treatment regimes; 1) after hyperoxia from postnatal day (P)7-11, or 2) concurrently with five days of hyperoxia from P1-5. Lung structure, function and macrophages were assessed using alveolar morphometry, barometric whole-body plethysmography and flow cytometry. RESULTS AND DISCUSSION: Seven days of hyperoxia resulted in an 18% decrease in body weight and perturbation of lung structure and function. In regime 1, growth restriction persisted in the Hyp + PBS and Hyp + CSF-1 groups, although perturbations in respiratory function were resolved by P35. CSF-1 increased CSF-1R+/F4/80+ macrophage number by 34% at P11 compared to Hyp + PBS, but was not associated with growth or lung structural rescue. In regime 2, five days of hyperoxia did not cause initial growth restriction in the Hyp + PBS and Hyp + CSF-1 groups, although body weight was decreased at P35 with CSF-1. CSF-1 was not associated with increased macrophages, or with functional perturbation in the adult. Overall, CSF-1 did not rescue the growth and lung defects associated with hyperoxia in this model; however, an increase in CSF-1R+ macrophages was not associated with an exacerbation of lung injury. The trophic functions of macrophages in lung development requires further elucidation in order to explore macrophage modulation as a strategy for promoting lung maturation.

A safety and feasibility study of an allogeneic colon cancer cell vaccine administered with a granulocyte-macrophage colony stimulating factor-producing bystander cell line in patients with metastatic colorectal cancer.

BACKGROUND: Despite recent advances in earlier detection and improvements in chemotherapy, the 5-year survival rate of patients with metastatic colorectal carcinoma remains poor. Immunotherapy is a potentially effective therapeutic approach to the treatment of colorectal carcinoma. Preclinical studies have supported the antitumor activity of immunization with a granulocyte-macrophage colony-stimulating factor (GM-CSF) producing murine colon tumor cell vaccine. METHODS: A novel colorectal cancer vaccine composed of irradiated, allogeneic human colon cancer cells and GM-CSF-producing bystander cells was developed and tested in combination with a single intravenous low dose of cyclophosphamide in a phase 1 study of patients with metastatic colorectal cancer. RESULTS: A total of nine patients were enrolled onto and treated in this study. Six patients had a history of colorectal adenocarcinoma hepatic metastases and underwent curative metastasectomy, while three other patients had unresectable stage IV disease. This study demonstrates the safety and feasibility of this vaccine administered in patients with metastatic colorectal cancer. At last follow-up, the six patients who underwent curative metastasectomy survived longer than 36 months, and four of these six patients were without disease recurrence. Immunologic correlate results suggest that the GM-CSF-producing colon cancer vaccine enhances the production of anti-MUC1 antibodies. CONCLUSIONS: This vaccine is feasible and safe. Future investigation of the efficacy and antitumor immunity of this vaccine is warranted.

Characterisation of a novel Fc conjugate of macrophage colony-stimulating factor.

We have produced an Fc conjugate of colony-stimulating factor (CSF) 1 with an improved circulating half-life. CSF1-Fc retained its macrophage growth-promoting activity, and did not induce proinflammatory cytokines in vitro. Treatment with CSF1-Fc did not produce adverse effects in mice or pigs. The impact of CSF1-Fc was examined using the Csf1r-enhanced green fluorescent protein (EGFP) reporter gene in MacGreen mice. Administration of CSF1-Fc to mice drove extensive infiltration of all tissues by Csf1r-EGFP positive macrophages. The main consequence was hepatosplenomegaly, associated with proliferation of hepatocytes. Expression profiles of the liver indicated that infiltrating macrophages produced candidate mediators of hepatocyte proliferation including urokinase, tumor necrosis factor, and interleukin 6. CSF1-Fc also promoted osteoclastogenesis and produced pleiotropic effects on other organ systems, notably the testis, where CSF1-dependent macrophages have been implicated in homeostasis. However, it did not affect other putative CSF1 targets, notably intestine, where Paneth cell numbers and villus architecture were unchanged. CSF1 has therapeutic potential in regenerative medicine in multiple organs. We suggest that the CSF1-Fc conjugate retains this potential, and may permit daily delivery by injection rather than continuous infusion required for the core molecule.

Colony-stimulating factor 1 receptor (CSF1R) signaling in injured neurons facilitates protection and survival.

Colony-stimulating factor 1 (CSF1) and interleukin-34 (IL-34) are functional ligands of the CSF1 receptor (CSF1R) and thus are key regulators of the monocyte/macrophage lineage. We discovered that systemic administration of human recombinant CSF1 ameliorates memory deficits in a transgenic mouse model of Alzheimer's disease. CSF1 and IL-34 strongly reduced excitotoxin-induced neuronal cell loss and gliosis in wild-type mice when administered systemically before or up to 6 h after injury. These effects were accompanied by maintenance of cAMP responsive element-binding protein (CREB) signaling in neurons rather than in microglia. Using lineage-tracing experiments, we discovered that a small number of neurons in the hippocampus and cortex express CSF1R under physiological conditions and that kainic acid-induced excitotoxic injury results in a profound increase in neuronal receptor expression. Selective deletion of CSF1R in forebrain neurons in mice exacerbated excitotoxin-induced death and neurodegeneration. We conclude that CSF1 and IL-34 provide powerful neuroprotective and survival signals in brain injury and neurodegeneration involving CSF1R expression on neurons.

Complete remission following chemotherapy with low-dose cytosine arabinoside and macrophage colony-stimulating factor/granulocyte colony-stimulating factor in a patient with relapsed acute myeloid leukemia after stem cell transplantation.

The prognosis of patients who relapse with acute myeloid leukemia (AML) after undergoing stem cell transplantation (SCT) is poor. There exist some treatments for relapsed AML; however, almost all treatments are associated with a high level of regimen-related toxicities (RRTs). The RRT of donor lymphocyte infusion is lower than that of other treatments; however, the efficacy of this treatment in treating patients with relapsed AML is lower than that observed in patients with chronic myelomonocytic leukemia. We herein report a case of relapsed AML after SCT in a 65-year-old man. We performed donor lymphocyte infusion; however, it was not effective. We then administered chemotherapy with cytosine arabinoside and macrophage colony-stimulating factor/granulocyte colony-stimulating factor and complete remission was achieved. Since graft-versus-host disease occurred after the administration of low-dose chemotherapy in this case, we speculated that the chemotherapy induced a graft-versus-leukemia effect.

Cytotoxic T cell immunity against the non-immunogenic, murine, hepatocellular carcinoma Hepa1-6 is directed towards the novel alternative form of macrophage colony stimulating factor.

Mouse Hepa1-6 hepatocellular carcinoma (HCC) cells were transduced with the membrane form of macrophage colony stimulating factor (mM-CSF). When mM-CSF transduced Hepa1-6 cells were injected subcutaneously into mice, these cells did not form tumors. The spleens of these immunized mice contained cytotoxic CD8+ T lymphocytes (CTL) that killed the unmodified Hepa1-6 cells. We show that the alternative form of macrophage colony stimulating factor (altM-CSF) induced CTL-mediated immunity against Hepa1-6 cells. AltM-CSF is restricted to the H-2D(b) allele. CTLs killed RMA-S cells loaded with exogenous altM-CSF peptide. Vaccination of mice with dendritic cells pulsed with the altM-CSF peptide stimulated anti-Hepa1-6 CTLs. Hyper-immunization of mice with mM-CSF Hepa1-6 cells showed inflammation of the liver and kidneys. Although altM-CSF was expressed within liver and kidney cells, its intensity was lower than Hepa1-6 cells. AltM-CSF was detected within the human HepG2 cell line. These studies suggest that altM-CSF may be a tumor antigen for HCC.

Administration of high-dose macrophage colony-stimulating factor increases bone turnover and trabecular volume fraction.

Macrophage colony-stimulating factor (M-CSF) is a hematopoietic growth factor that plays a critical role in early osteoclastogenesis. To characterize the skeletal effects of M-CSF, we administered soluble M-CSF to mice. It was hypothesized that M-CSF would stimulate bone formation through coupled activity of osteoclasts and osteoblasts. Twenty-four male C57BL/6 J mice (n = 12/group, aged 7 weeks) received subcutaneous injections of human M-CSF [5 mg/(kg day)] or inert vehicle (VEH) for 21 days. M-CSF increased serum bone turnover markers (+57% TRAP-5b and +44% osteocalcin). Microcomputed tomography revealed an anabolic effect on tibial trabecular bone, with higher bone volume fraction (+35%), connectivity density (+79%), and number (+18%), as well as lower trabecular separation (-18%). M-CSF had no significant effect on cortical bone mineral content, geometry, or strength. There was no change in quantitative histomorphometry parameters of femoral cortical bone. These results reveal the complex, site-specific effects of M-CSF. In particular, we have demonstrated an anabolic effect of M-CSF on trabecular bone achieved through coupled activation of osteoblasts. However, in contrast to previous studies, M-CSF was found to have no effect on cortical bone. M-CSF was demonstrated to significantly influence both bone modeling and remodeling in relatively young animals.

Second-line treatment of non small cell lung cancer by biweekly gemcitabine and docetaxel +/- granulocyte-macrophage colony stimulating factor and low dose aldesleukine.

Background. The antitumor activity of a novel biweekly gemcitabine (G) + docetaxel (D) regimen +/- granulocyte-macrophage colony stimulating factor (GM-CSF) and aldesleukine (IL-2) has been evaluated in a phase II trial in advanced pretreated non-small-cell lung cancer (NSCLC). Results. The treatment was well tolerated. The 42.3% response rate exceeded the predefined target activity, while time to progression (TTP) and overall survival (OS) were 7 and 11.2 months, respectively. A greater objective response rate (58.3% vs 28.6%) and an increased number of eosinophils, basophils and activated mononuclear blood cells were observed in those patients who also received cytokine administration. Methods. Twenty-six NSCLC patients received second line G (1000 mg/m2) and D (75 mg/m2) every 15 days. 12/26 patients also received s.c. GM-CSF (100µg, days 2-6) and s.c. IL-2 (0.5MIU/ twice daily, days 7-14 and 16-29) by random selection. Conclusion. The biweekly GD regimen is a safe and active second-line treatment in NSCLC. Addition of immune-adjuvant cytokines' may enhance the activity of this therapeutic combination.