Anti-tumoral effect of GM-CSF with or without cytokines and monoclonal antibodies in solid tumors

The multifaceted role of Th17 lymphocytes and their associated cytokines in cancer

While the role of T helper 17 lymphocytes (Th17) in the pathogenesis of autoimmune diseases and in infectious immunity has been relatively well defined, the impact of these cells and their associated cytokines on cancer development is still under debate. Although multiple reports have indicated that Th17 can promote anticancer immunity, others have argued that these cells may exhibit tumor-promoting properties. This dichotomy in the function of Th17 lymphocytes in cancer may be related to the versatile nature of these cells, being capable of differentiating into either proinflammatory Th1 or suppressive FoxP3-expressing Treg cells or hybrid T cell subsets depending on the underlying environmental conditions. In the current review, we examine the role of Th17 lymphocytes and Th17-associated cytokines in cancer and discuss how factors that control their final lineage commitment decision may influence the balance between their tumor-promoting versus tumor-suppressing properties.

Addition of GM-CSF to trastuzumab stabilises disease in trastuzumab-resistant HER2+ metastatic breast cancer patients

Background:

One of the proposed mechanisms of trastuzumab-induced regression of human epidermal growth factor receptor 2-positive (HER2+) tumours includes facilitation of antibody-dependent cell-mediated cytotoxicity (ADCC). Granulocyte-macrophage colony-stimulating factor (GM-CSF) mediates ADCC. We presented our pilot study of adding GM-CSF to trastuzumab in patients with trastuzumab-resistant HER2+ metastatic breast cancer.

Methods:

Patients with HER2+ metastatic breast cancer that progressed after trastuzumab +/− chemotherapy were continued on trastuzumab 2 mg kg^–1 intravenous weekly and GM-CSF 250 μg m^–2 subcutaneous daily. Patients were assessed for response every 8 weeks. Treatment was continued until disease progression or intolerable toxicity.

Results:

Seventeen patients were evaluable (median age 48 years, range 27–75 years). The median number of metastatic sites was 2 (range 1–3); the most common site was the liver (n=10). The median number of prior regimens for metastatic disease was 2 (range 1–5). No objective disease response was observed, but five patients (29%) had stable disease for a median duration of 15.8 (range 10–53.9) weeks. The most common adverse event was rash at the injection site. No grade 4 or irreversible adverse event was seen.

Conclusion:

The addition of GM-CSF to trastuzumab alone had a modest clinical benefit and acceptable safety profile in heavily pretreated patients with trastuzumab-resistant HER2+ metastatic breast cancer.

Long term administration of granulocyte-macrophage colony stimulating factor decreases development of 1-2 dimethylhydrazine-induced colon cancer in rats

BACKGROUND AND OBJECTIVES

The antitumoral activities of granulocyte-macrophage colony stimulating factor (GM-CSF) were shown earlier. In this study, the effects of GM-CSF were investigated on colon cancer induced by 18 weeks of 1-2 dimethylhydrazine (DMH) administration in rats.

METHODS

Four groups received subcutaneous saline (n = 20), 15 mg/kg DMH (n = 30), DMH +6 microg/kg GM-CSF (n = 30), and DMH +12 microg/kg (n = 30) GM-CSF.

RESULTS

The average number of tumors (2.8 vs. 1.5) and mean tumor volume (179 +/- 36 vs. 27 +/- 9 mm(3); means +/- SEM) were reduced in DMH + GM-CSF groups as compared to the DMH group (n = 30, P < 0.01). DMH-induced enhancement of free radicals and lipid peroxidation were decreased in DMH + GM-CSF group (n = 8-12, P < 0.05). The magnitude of DMH-induced alterations in superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities was lowered in the DMH + GM-CSF group (n = 12-16, P < 0.05). DMH-induced increases in the total nitrite/nitrate levels and the nitric oxide synthase (NOS) activity (n = 10-12, P < 0.05) were also reduced in the DMH + GM-CSF group (n = 8-9, P < 0.05).

CONCLUSIONS

The results indicate that GM-CSF inhibits the development of DMH-induced colon cancer in rats and suggest that inhibition of oxidative stress and NO pathway are involved in the observed antitumoral effects.

Concurrent administration of granulocyte colony-stimulating factor or granulocyte-monocyte colony-stimulating factor enhances the biological activity of rituximab in a severe combined immunodeficiency mouse lymphoma model

A predominant percentage of the in vivo antitumor activity of rituximab occurs through antibody-dependent cellular cytotoxicity (ADCC) via FcgammaRIII receptors. Co-expression of CD11b/CD18 (MAC-1), an adhesion molecule present in activated neutrophils, plays an important role in the induction of ADCC. The effects of granulocyte-monocyte colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) on the biological activity of rituximab were studied in a non-Hodgkin's lymphoma (NHL)-bearing severe combined immunodeficiency (SCID) mouse model. Natural killer (NK) cell-depleted SCID mice were inoculated intravenously with Raji cells. Animals were divided into 6 cohorts: group A: placebo (saline injection); group B: murine (m)-G-CSF; group C: m-GM-CSF; group D: rituximab alone; group E: concurrent m-G-CSF and rituximab; and group F: concurrent m-GM-CSF and rituximab. Treatment with G-CSF or GM-CSF led to a 1.5- to 2-fold increase of CD11b/CD18 expression in neutrophils. Treatment with G-CSF led to the highest expression of CD11b/CD18 on neutrophils. No antitumor activity was observed among mice treated with G-CSF or GM-CSF alone. After 3 months, survival rates were highest in animals treated with rituximab and G-CSF (53.3%) compared to rituximab alone (13.3%) or in combination with peg-GM-CSF (26.7%). Increasing neutrophil counts via cytokine stimulation may play an important role in augmenting rituximab-associated antitumor activity.

Myeloid growth factors in oncology

Within the last decade haemopoietic growth factors have become established in the pharmacopoeia of oncology. In the form of granulocyte colony-stimulating factor (G-CSF), and to a lesser extent granulocyte-macrophage colony-stimulating factor (GM-CSF), these proteins are routinely used to accelerate restoration of neutrophil count after chemotherapy or bone marrow transplant. Their main advance has been the development of mobilisation protocols. Peripheral blood progenitor cells are induced to egress from the bone marrow and re-transfusion after myelosuppressive chemotherapy allows for a simple and more rapid form of autologous transplantation than bone marrow transplantation. This review will give a brief overview of the biology of haemopoiesis in relation to growth factors and the potential lines of further research. Although the established clinical uses of G-CSF will be discussed the main focus will be on the developmental applications, such as ex vivo haemopoiesis, dose intensification schedules and the application of growth factors in the therapy of haematological malignancies. The relevance of novel or more recently introduced recombinant haemopoietic growth factors will also be discussed in relation to these indications.

Human cytomegalovirus (HCMV) infection in osteosarcoma cell line suppresses GM-CSF production by induction of TGF-beta

This study was performed to elucidate the possible mechanism of the disturbance of hemopoiesis by HCMV infection. Saos-2 cells constitutively express mRNA of GM-CSF, and its expression was profoundly decreased by HCMV infection, which required full replication of the virus and was mediated by soluble factors released from the HCMV-infected Saos-2 cells. TGF-beta1 production was statistically and significantly increased from one day after HCMV infection. Expression and production of GM-CSF in Saos-2 cells were restored when a culture supernatant of HCMV-infected Saos-2 cells was reacted with neutralizing anti-TGF-beta antibody. Conclusively, HCMV inhibits GM-CSF expression in Saos-2 cells partly by the increased production of TGF-beta1.

Immunotherapy with concurrent subcutaneous GM-CSF, low-dose IL-2 and IFN-alpha in patients with progressive metastatic renal cell carcinoma

The purpose of the study was to determine toxicity, efficacy and immunologic effects of concurrent subcutaneous injections of low-dose interleukin-2 (LD-IL-2), granulocyte-monocyte colony-stimulating factor (GM-CSF) and interferon-alpha 2b (IFNalpha) in progressive metastatic renal cell carcinoma. In a multicentre phase II study, 59 evaluable patients received two to six cycles of subcutaneous IL-2 (4 mIU m(-2)), GM-CSF (2.5 microg kg(-1)) and IFNalpha (5 mIU flat(-1)) for 12 days per 3 weeks with evaluation after every two cycles. Cycles were repeated in responding or stable patients. Data were analysed after a median of 30 months follow-up (range 16-48 months). In 42 patients, the immunologic response was studied and related to response and survival. The main toxicity were flu-like symptoms, malaise and transient liver enzyme elevations, necessitating IL-2 reduction to 2 mIU m(-2) in 29 patients, which should be considered the maximal tolerable dose. The response was 24% (eight out of 34, three complete response (CR), five partial response (PR)) in patients with metachronic metastases and 12% (three out of 25, 2CR, 1PR) in patients with synchronic metastases. Overall response was 19% (11 out of 59). Median survival was 9.5 months. All tested patients showed expansion and/or activation of lymphocytes, T cells and subsets, NK cells, eosinophils and monocytes. Pretreatment HLA-DR levels on monocytes and number of CD4(+)HLA-DR(+) cells correlated with response. Pretreatment number of CD4(+)HLA-DR(+) cells and postimmunotherapy levels of lymphocytes, CD3(+), CD4(+) and CD8(+) T cells, but not of NK or B cells, correlated with prolonged survival. Immunotherapy with concurrent subcutaneous GM-CSF, LD-IL-2 and IFNalpha has limited toxicity, can be given as outpatient treatment and can induce durable CR. Response and survival with this form of immunotherapy seem to be more dependent on expansion/activation of T cells than of NK cells.

Modulation by colony stimulating factors of human epithelial colon cancer cell apoptosis

Colony stimulating factors (CSF) promote leukocyte survival by reducing apoptotic cell death. However, their effects on non-leukocyte cell types are unclear. Reduced apoptosis in colon epithelial cells is thought to contribute to the initiation of cancer. Here, we report diminished spontaneous apoptosis of human colon epithelial HT-29 cells in the presence of macrophage-CSF or granulocyte macrophage-CSF. Moreover, reduced apoptosis induced by sulindac sulfide was also observed with macrophage-CSF. Granulocyte-CSF failed to modify spontaneous or sulindac sulfide induced apoptosis. It seems, therefore, that the action of CSFs on apoptosis is not confined to haematopoietic cells but may be extended to stromal cells.

A potential role of macrophage activation in the treatment of cancer

One of the functions of macrophages is to provide a defense mechanism against tumor cells. In the last decades the mechanism of tumor cell killing by macrophages have been studied extensively. The tumor cytotoxic function of macrophages requires stimulation either with bacterial cell wall products such as lipopolysaccharide (LPS) or muramyldipeptide (MDP) or with cytokines such as interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Activated macrophages secrete several substances that are directly involved in tumor cell killing i.e. tumor necrosis factor (TNF) and nitric oxide (NO). On the other hand, substances are secreted that are able to stimulate tumor cell growth, depending on the stage and the nature of the tumor. Several clinical trials have been performed aiming at the activation of macrophages or dendritic cells, a subpopulation of the macrophages. In this review we will summarize and discuss experimental studies and clinical trials based on the activation of macrophages.

Thymidine phosphorylase expression in normal, hyperplastic and neoplastic prostates: correlation with tumour associated macrophages, infiltrating lymphocytes, and angiogenesis

Thymidine phosphorylase is an angiogenic factor primarily expressed by cancer cells, stromal cells and tumour-associated macrophages in many human malignancies. These different types of thymidine phosphorylase-expressing cells, however, may have a distinct place in the angiogenic process, and this question was addressed in the present study. A series of 20 normal/hyperplastic prostate glands and 60 prostate carcinomas was investigated by immunohistochemistry, using specific antibodies for thymidine phosphorylase (P-GF.44C), tumour-associated macrophages (CD68), endothelium (CD31) and prostate specific antigen (ER-PR8). Thymidine phosphorylase expression by normal and hyperplastic epithelial or stromal cells occurred almost exclusively in the context of an intense lymphocytic infiltrate. High thymidine phosphorylase cancer cells and thymidine phosphorylase stromal cells expression was associated with high angiogenesis in prostate carcinomas, and this significant association was extended to include both tumour-associated macrophages and tumour-infiltrating lymphocytes. Thymidine phosphorylase expression and tumour-infiltrating lymphocytes were related inversely with prostate specific antigen reactivity. In conclusion, thymidine phosphorylase is a major angiogenic factor in prostate carcinomas and its up-regulation is likely to occur in the context of a host immune response.

Growth stimulation of non-small cell lung cancer xenografts by granulocyte-macrophage colony-stimulating factor (GM-CSF)

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been suggested to be involved in the carcinogenesis of some types of tumours by autocrine or paracrine mechanisms. We examined GM-CSF/GM-CSF receptor (GM-CSFR) gene expression in 20 human non-small cell lung cancer (NSCLC) xenografts. The stimulatory effects of GM-CSF were examined using GM-CSF transgenic severe combined immunodeficient (SCID) mice (GM-Tg-SCID), which produce abundant human GM-CSF. A NSCLC xenograft (LC11-JCK), expressed GM-CSFR but not GM-CSF, and showed more rapid growth in GM-Tg-SCID than non-GM-CSF transgenic SCID mice (non-Tg-SCID). GM-CSF gene expression was detected in 48 of 90 (53%) primary NSCLC human specimens and GM-CSFR gene expression was detected in 42 specimens (47%). GM-CSF expression was detected in 13 of 30 squamous cell carcinoma specimens (43%) and GM-CSFR expression was detected in 10 specimens (33%). Patients with squamous cell carcinoma coexpressing GM-CSF and GM-CSFR showed significantly poorer prognosis than those expressing neither GM-CSF nor GM-CSFR (P < 0.05, Cox-Mantel test). These results suggest that GM-CSF can have a stimulatory effect on some NSCLC.