Frequent expression of receptors for granulocyte-macrophage colony-stimulating factor on human nonhematopoietic tumor cell lines

Role of the hematopoietic cytokines SCF, IL-3, GM-CSF and M-CSF in the diagnosis of pancreatic and ampullary cancer

BACKGROUND

Previous studies have demonstrated altered levels of hematopoietic cytokines in the serum of patients with different types of cancer.

METHODS

We measured the serum levels of the hematopoietic cytokines stem cell factor (SCF), interleukin 3 (IL-3), macrophage-colony stimulating factor (M-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) in 40 pancreatic and ampullary cancer patients and 40 healthy volunteers, using ELISA. We also assessed the most widely used pancreatic tumor markers, carbohydrate antigen 19-9 (CA 19-9) and carcinoembryonic antigen (CEA), in both groups. We then correlated the concentrations of the cytokines' and the tumor markers in the patients' serum and we estimated their diagnostic ability by calculating diagnostic sensitivity and specificity, positive and negative predictive values and the receiver operating characteristic (ROC) curve.

RESULTS

The SCF and IL-3 levels were significantly lower and the M-CSF levels significantly higher in pancreatic cancer patients than in controls. There were significant positive correlations between the serum levels of CEA and M-CSF, GM-CSF and SCF, and between GM-CSF and IL-3. The area under the ROC curve and diagnostic sensitivity of M-CSF were greater than those of SCF and IL-3. The diagnostic sensitivity of the combined use of SCF and M-CSF reached 97.5%.

CONCLUSION

The diagnostic ability of M-CSF and SCF in pancreatic and ampullary cancer should stimulate further studies evaluating their clinical usefulness as tumor markers.

Granulocyte-macrophage colony-stimulating factor as an autocrine survival-growth factor in human gliomas

We studied the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptors (GM-CSF.R) in 20 human brain gliomas with different tumor gradings and demonstrated constitutive high levels of both mRNA gene expression and protein production exclusively in the highest-grade tumors (WHO, III-IV grade). Five astrocytic cell lines were isolated in vitro from glioma cells, which had selectively adhered to plates pre-coated with rhGM-CSF. These cells were tumorigenic when xenografted to athymic mice, and produced GM-CSF constitutively in culture. Two lines, particularly lines AS1 and PG1, each from a patient with glioblastoma multiforme, constitutively over-expressed both GM-CSF and GM-CSF.R genes and secreted into their culture media biologically active GM-CSF. Different clones of the AS1 line, isolated after subsequent passages in vitro and then transplanted to athymic mice, demonstrated higher tumorigenic capacity with increasing passages in vivo. Cell proliferation was stimulated by rhGM-CSF in late-stage malignant clones, whereas apoptosis occurred at high frequency in the presence of blocking anti-GM-CSF antibodies. In contrast, rhGM-CSF did not induce any apparent effect in early-stage clones expressing neither GM-CSF nor GM-CSF.R. The addition of rhGM-CSF or rhIL-1β, to cultures induced the overproduction of both GM-CSF and its receptors and increased gene activation for several functional proteins (e.g. NGF, VEGF, VEGF.R1, G-CSF, MHC-II), indicating that these cells may undergo dynamic changes in response to environmental stimuli. These findings thus revealed: (1) that the co-expression of both autocrine GM-CSF and GM-CSF.R correlates with the advanced tumor stage; (2) that an important contribution of GM-CSF in malignant glioma cells is the prevention of apoptosis. These results imply that GM-CSF has an effective role in the evolution and pathogenesis of gliomas.

G- and GM-CSF in oncology and oncological haematology

Administration of G- and GM-CSF increases the neutrophil counts in a number of clinical situations. GM-CSF shows the additional effect of increasing the number of monocytes and eosinophil granulocytes. Both G- and GM-CSF affect of neutrophil functions, in the case of GM-CSF there are some potentially negative effects on neutrophil migration and adhesiveness. The clinical relevance of the various effects on mature haematopoietic cells is not fully understood. Clinical data with G-CSF treatment indicate that increased levels of neutrophil granulocytes following cytotoxic chemotherapy may translate into clinical benefit such as a decreased rate of neutropenic infection and an increased cytotoxic chemotherapy dose even though the data are conflicting and the risk of "laboratory cosmetics" is apparent. Regarding treatment with GM-CSF following chemotherapy, the clinical benefit is unclear. The clinical benefit of GM-CSF-induced monocytes and eosinophils is unknown. G- and GM-CSF accelerates neutrophil recovery following autologous or allogeneic BMT. The influence on neutropenic infections is, however, less impressive. Pretreatment with G- or GM-CSF increases the yield of peripheral stem cell harvest, thereby reducing the number of leukaphereses needed. Transplantation of G- and GM-CSF primed autologous peripheral stem cells tends to reduce the period of post-transplant cytopenia, particularly thrombocytopenia, in comparison with traditional ABMT. In patients with MDS, G- and GM-CSF appear to increase the number of neutrophil granulocytes and there is some evidence that patients with severe infectious problems will benefit from this treatment. However, little influence was seen on the main clinical problems with these patients, which are anaemia and thrombocytopenia. In conclusion, G- and GM-CSF are two different proteins with different properties in vivo and in vitro. GM-CSF has, compared with G-CSF, more complex pharmacological effects and a more trouble-some side-effect profile. Early clinical development indicates that both compounds have a substantial influence on the levels of certain blood cells. Whether the increases in different blood cells translate into long-term clinical benefit for greater patient groups is the focus of ongoing research. The effects of G- and GM-CSF may be potentiated by other cytokines, an area which is presently being explored.

The diagnostic value of G-CSF measurement in the sera of colorectal cancer and adenoma patients

BACKGROUND

Granulocyte-colony stimulating factor (G-CSF) regulates the growth of hematopoietic progenitor cells. Cancer cells, including colorectal cancer, can produce this cytokine. The aim of this study was to compare the diagnostic value of measurement of G-CSF and classic tumor markers--carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) in the sera of colorectal cancer with adenoma patients and to determine its usefulness in the diagnosis of colorectal cancer and polyps.

PATIENTS AND METHODS

The serum levels of G-CSF and tumor markers were assayed in 76 colorectal cancer, 35 colorectal adenoma patients and in 65 healthy subjects. We defined the diagnostic sensitivity, specificity and areas under ROC curves for the measurands.

RESULTS

Median values of G-CSF and tumor markers were significantly higher in colorectal cancer patients than those in healthy subjects. There were significant differences in the serum levels of G-CSF between adenoma patients and healthy subjects. The concentrations of tumor markers in colorectal cancer patients were higher than those in polyps. Combined use of G-CSF with CEA improved their diagnostic sensitivity in colorectal cancer.

CONCLUSIONS

Measurement of G-CSF might be useful in the diagnosis of colorectal cancer patients, but not in the differentiation between colorectal cancer and polyps.

Stem cell factor and macrophage-colony stimulating factor in patients with pancreatic cancer

Stem cell factor (SCF) and macrophage-colony stimulating factor (M-CSF) have assumed an increasing importance in cancer biology. In the present study we investigated the serum levels of these cytokines in pancreatic cancer patients in relation to controls and to patients with benign lesions of the pancreas (chronic pancreatitis group). The classical tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) were also tested. We compared the serum levels of cytokines with tumor stage. We also defined the receiver-operating characteristics (ROC) curve for cytokines and classical tumor markers. The cytokines were measured in 47 patients with pancreatic cancer, in 27 patients with chronic pancreatitis and in 35 healthy subjects. SCF and M-CSF were determined using enzyme-linked immunosorbent assay (ELISA). CEA and CA 19-9 were measured by microparticle enzyme immunoassay. There were significant differences in the levels of circulating SCF, M-CSF, CEA and CA 19-9 in the pancreatic cancer patients compared to the control group, but only the serum levels of M-CSF, CEA and CA 19-9 were significantly higher in pancreatic cancer patients compared to the pancreatitis group. The levels of cytokines and tumor markers were higher in patients with a more advanced tumor stage. The M-CSF serum levels correlated positively with the tested tumor markers. The M-CSF area under the ROC curve was higher than the SCF area. These results suggest that M-CSF is a better candidate for a pancreatic cancer tumor marker than SCF.

Hematopoietic cytokines as tumor markers

Stem cell factor (SCF), interleukin 3 (IL-3), granulocyte-macrophage-colony stimulating factor (GM-CSF), granulocyte-colony stimulating factor (G-CSF) and macrophage-colony stimulating factor (M-CSF) are members of a group of glycoproteins called hematopoietic cytokines (HCs). These cytokines regulate the growth and differentiation of hematopoietic progenitor cells and functionally activate mature neutrophils or macrophages. The effect of HCs is not limited to bone marrow cells. Some studies have shown that HCs can also stimulate the proliferation of non-hematopoietic cells. The receptors for HCs have been detected in cancer cell lines, and stimulation of HCs receptors induced proliferation of tumor cells. Moreover, some investigations have shown HC mRNA expression in these cell lines and recent studies have demonstrated that HCs can stimulate tumor progression. Several cells of malignant tumors have been observed to secrete large amounts of HCs and increased concentrations of HCs have been found in the sera of cancer patients. There are a number of situations in which the measurement of HCs may provide clinically useful information, particularly regarding prognosis and response to treatment. In this paper we discuss the results of studies that have examined the potential use of HCs as tumor markers.

Effect of serum deprivation on constitutive production of granulocyte-colony stimulating factor and granulocyte macrophage-colony stimulating factor in lung cancer cells

We previously established 2 lung cancer cell lines, OKa-C-1 and MI-4, which constitutively produce an abundant dose of granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage-colony stimulating factor (GM-CSF). Many other cases with G-CSF or GM-CSF producing tumors have been reported up to the present. However, the biological properties of the overproduction of G-CSF and GM-CSF by tumor cells have not been well known. Several reports demonstrated the presence of an autocrine growth loop for G-CSF and GM-CSF in nonhematopoietic tumor cells. We showed that exogenous G-CSF and GM-CSF stimulated cell growth in a dose-dependent manner in OKa-C-1 and MI-4 cells. We could detect the presence of G-CSF and GM-CSF receptors in both cell lines by RT-PCR analysis. We have previously shown that inflammatory cytokines, tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta enhance the expression of G-CSF and GM-CSF in the cell lines. However, the factors that regulate constitutive production of G-CSF or GM-CSF by tumor cells are still unknown well. In our study, we first reported that serum deprivation stimulated constitutive production of G-CSF and GM-CSF by lung tumor cells through activation of nuclear factor (NF)-kappaB and p44/42 mitogen-activated protein kinase (MAPK) pathway signaling. We suggest that G-CSF and GM-CSF constitutively produced by tumor cells could grow tumor itself and rescue tumor cells from the cytotoxicity of serum deprivation.

Hematopoietic growth factors in colorectal cancer patients

Hematopoietic growth factors (HGFs) are involved in the regulation of growth and spread of cancer. Therefore, in the present study, we have investigated in colorectal cancer patients the serum levels of selected HGFs, such as stem cell factor (SCF), interleukin 3 (IL-3), granulocyte-macrophage-colony stimulating factor (GM-CSF), and M-CSF in relation to controls and to the classical tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) in colorectal cancer. Additionally, we have compared the serum levels of cytokines with tumor site and stage and other clinical characteristics such as age and sex. We also defined the receiver-operating characteristics (ROC) curve for HGFs and classical tumor markers. The tested cytokines were measured in 70 patients with colorectal cancer and in 40 healthy subjects. HGFs were determined using enzyme-linked immunosorbent assay (ELISA). CEA and CA 19-9 were measured by microparticle enzyme immunoassay. There were significant differences in the levels of circulating SCF, IL-3, M-CSF, GM-CSF, and CEA and CA 19-9 in the colorectal cancer patients compared to the control group. The levels of M-CSF and CEA were significantly higher in patients with a more advanced tumor stage. The significant positive correlation was observed between the CEA and CA 19-9 concentrations. The M-CSF serum levels correlated positively with the tested tumor markers. The M-CSF area under the ROC curve was the largest. These results suggest that M-CSF is, among the tested HGFs, the best candidate for a colorectal cancer tumor marker.

Cyclooxygenase-2 inhibitor NS-398 suppresses cell growth and constitutive production of granulocyte-colony stimulating factor and granulocyte macrophage-colony stimulating factor in lung cancer cells

We previously established two lung cancer cell lines, OKa-C-1 and MI-4, which constitutively produce abundant granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage-colony stimulating factor (GM-CSF). Inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta stimulated the expression of G-CSF, GM-CSF, and cyclooxygenase (COX)-2 in the two cell lines. It is known that increased COX-2 activity promotes tumor growth and induces G-CSF and GM-CSF expression in non-malignant cells, and that selective COX-2 inhibitors inhibit the growth of some types of malignant cells. Therefore, we hypothesized that inhibition of COX-2 activity might suppress constitutive production of G-CSF or GM-CSF in addition to reducing the growth of malignant cells. We confirmed that the selective COX-2 inhibitor, NS-398 suppressed the constitutive production of G-CSF and GM-CSF, and the cell growth in both OKa-C-1 and MI-4 cell lines. Prostaglandin E2 (PGE2) reversed the inhibitions of G-CSF and GM-CSF expression, as well as cell growth, by NS-398. This result confirms that the effects of NS-398 are based on the inhibition of COX activity. Some studies have indicated that nuclear factor kappa B (NF-kappaB) or MAPK (mitogen-activated protein kinase) activation is related to upregulation of G-CSF, GM-CSF or COX-2 expression in some types of cells. Therefore, we examined if the actions of NS-398 might be mediated by the MAP kinase pathway or NF-kappaB activity in OKa-C-1 and MI-4 cells. We found that NS-398 inhibits G-CSF and GM-CSF production and cell growth through an extracellular signal-regulated kinase kinase (MEK) signaling pathway in these cell lines. The prognosis of non-small cell lung cancer showing G-CSF gene expression is significantly worse. G-CSF overproduction by tumor cells is observed at an advanced clinical stage. Our findings imply that a COX-2 inhibitor might improve the prognosis of patients with lung cancer through the reduction of G-CSF or GM-CSF.

Granulocyte-colony stimulating factor (G-CSF) and macrophagecolony stimulating factor (M-CSF) in colorectal cancer patients

We have investigated the serum level of granulocytecolony stimulating factor (G-CSF) and macrophagecolony stimulating factor (M-CSF) and the commonly accepted tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) in colorectal cancer. Additionally, we have defined the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and receiver-operating characteristics (ROC) curve for G-CSF and M-CSF. The serum levels of cytokines were measured in 49 patients with colorectal cancer and in 40 healthy subjects. G-CSF and M-CSF were determined using enzyme-linked immunosorbent assay (ELISA). CEA and CA 19-9 were measured by microparticle enzyme immunoassay. There were significant increases in the level of circulating G-CSF and M-CSF in the colorectal cancer patients compared to the control group. Moreover, the diagnostic sensitivity of M-CSF was higher (65%) than the sensitivity of CEA (31%) and CA 19-9 (20%). The diagnostic specificities of M-CSF and G-CSF were 95%, and the M-CSF predictive value was higher compared with the predictive value of G-CSF. These results suggest a potential role for M-CSF as a tumor marker for colorectal cancer.

Expression of GM-CSF receptors in male germ cells and their role in signaling for increased glucose and vitamin C transport

We studied the expression and function of the granulocyte-macrophage colony stimulating factor (GM-CSF) receptor in male germ cells. RT-PCR showed expression of mRNAs encoding the alpha- and beta-subunits of the GM-CSF receptor in human testis, and the presence of the alpha- and beta-proteins was confirmed by immunoblotting with anti-alpha and anti-beta-antibodies. Immunolocalization studies showed the level of expression of GM-CSF alpha- and beta-subunits in the germ line in the testis and in ejaculated spermatozoa. Receptor binding studies using radiolabeled GM-CSF revealed that bull spermatozoa have about 105 high-affinity sites with a K(d) of 222 pM and approximately 1100 low-affinity sites with a K(d) of 10 nM. GM-CSF signaled, in a time- and dose-dependent manner, for an increased uptake of glucose and vitamin C.

Granulocyte-Colony stimulating factor and macrophage-colony stimulating factor in patients with non-small-cell lung cancer

We have investigated the serum level of granulocyte-colony stimulating factor (G-CSF) and macrophagecolony stimulating factor (M-CSF) in non-small-cell lung cancer (NSCLC), in relation to the control group and commonly accepted tumor markers, such as carcinoembryonic antigen (CEA) and cytokeratin fragment 19 (CYFRA 21-1). Additionally, we have defined the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and receiver-operating characteristics (ROC) curve of G-CSF and M-CSF. Serum levels of cytokines were measured in 61 patients with NSCLC and in 20 healthy subjects. G-CSF and M-CSF were determined using ELISA. CYFRA 21-1 was measured by radioimmunoassay and CEA by microparticle enzyme immunoassay. There were significant increases in the level of circulating G-CSF in the lung cancer patients compared to the control group. Moreover, the diagnostic sensitivity of G-CSF was higher (56%) than the sensitivity of CYFRA 21-1 (51%), but lower than the CEA sensitivity (62%). The diagnostic specificity of G-CSF was higher (70%) than the M-CSF specificity (40%) and the G-CSF predictive values were higher in relation to the predictive values of M-CSF. These results suggest a potential role of G-CSF as a tumor marker for NSCLC.

Granulocyte-macrophage colony-stimulating factor upregulates matrix metalloproteinase-2 (MMP-2) and membrane type-1 MMP (MT1-MMP) in human head and neck cancer cells

Matrix metalloproteinase-2 (MMP-2) and membrane type 1-MMP (MT1-MMP) play an important role in the invasion and metastasis of head and neck squamous cell carcinoma (HNSCC), but the mechanism of their regulation is not clearly understood. Recently, granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to be associated with cancer invasion and metastasis. We hypothesized that GM-CSF may upregulate MMP-2 and/or MT1-MMP expression in HNSCC cells, and may thereby influence their ability to invade and metastasize. We studied the effects of GM-CSF on the production of MMP-2 and MT1-MMP in HNSCC cell lines SAS and HSC-2. Gelatin zymography of conditioned media derived from HNSCC cells revealed a major band of 68 kDa, which was characterized as proMMP-2. GM-CSF stimulated the production of proMMP-2 in both cell lines in a dose-dependent manner. Treatment with 50 ng/ml GM-CSF for 24 h increased the proMMP-2 activity 3.4-fold in SAS cells and 2.3-fold in HSC-2 cells compared with untreated controls. Northern blot analyses demonstrated that GM-CSF led to elevated mRNA levels of MMP-2 and MT1-MMP in both cell lines. The results identify GM-CSF as a regulator of MMP-2 and MT1-MMP expression in certain types of HNSCC, and suggest that GM-CSF may contribute to the invasiveness of HNSCC through the regulation of MMP-2 and MT1-MMP expression.

Stem cell factor and granulocyte-macrophage-colony stimulating factor as candidates for tumour markers for non-small-cell lung cancer

We have investigated the serum level of stem cell factor (SCF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) in relation to a control group and commonly accepted tumour markers, such as carcinoembryonic antigen (CEA) and cytokeratin fragment 19 (CYFRA 21-1). Additionally, we have defined the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and receiver-operating characteristics (ROC) curve of SCF and GM-CSF in non-small-cell lung cancer (NSCLC). The serum levels of cytokines were measured in 50 patients with NSCLC and in 20 healthy subjects. SCF and GM-CSF were determined using enzyme-linked immunosorbent assay (ELISA), CYFRA 21-1 was measured by radioimmunoassay and CEA by microparticle enzyme immunoassay. There were significant increases in circulating SCF and GM-CSF in the lung cancer patients compared to the control group. The diagnostic sensitivity of GM-CSF was higher (70%) than the sensitivity of CEA (62%) and CYFRA 21-1 (51%). The diagnostic specificity of GM-CSF was lower (65%) than SCF specificity (70%), but the GM-CSF predictive values were higher in relation to the predictive values of SCF. These results suggest a potential role of SCF and GM-CSF as tumour markers for NSCLC.

Expression of Granulocyte-Macrophage Colony-Stimulating Factor Receptors in Human Prostate Cancer

We studied the expression and function of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor in the human prostate carcinoma cell line LNCaP and looked for its presence in normal and neoplastic human prostatic tissue. The GM-CSF receptor is composed of two subunits, α and β. While the isolated α subunit binds GM-CSF at low-affinity, the isolated β subunit does not bind GM-CSF by itself; but complexes with the α subunit to form a high-affinity receptor. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) showed expression of mRNAs encoding the α and β subunits of the GM-CSF receptor in LNCaP cells, and the presence of the α and β proteins was confirmed by immunolocalization with anti-α and anti-β antibodies. Receptor binding studies using radiolabeled GM-CSF showed that LNCaP cells have about 150 high-affinity sites with a kd of 40 pmol/L and approximately 750 low-affinity sites with a kd of 2 nmol/L. GM-CSF signaled, in a time- and dose-dependent manner, for protein tyrosine phosphorylation and induced the proliferation of the LNCaP cells. Immunolocalization studies showed low level expression of GM-CSF α and β subunits in normal prostate tissue, with substantial expression in benign prostatic hyperplasia and prominent expression in neoplastic prostate tissue. Maximal expression of both subunits was observed in prostatic carcinomas metastatic to lymph node and bone. Tumor cells that stained positively with anti-α subunit antibodies were also reactive with anti-β subunit antibodies, indicating that they express high-affinity GM-CSF receptors. Our data show that the LNCaP cells express functional GM-CSF receptors and that prostatic carcinomas have prominent GM-CSF receptor expression. These findings imply that both hyperplastic and neoplastic prostatic tissues may be responsive to GM-CSF.

Expression of Granulocyte-Macrophage Colony-Stimulating Factor Receptors in Human Prostate Cancer

We studied the expression and function of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor in the human prostate carcinoma cell line LNCaP and looked for its presence in normal and neoplastic human prostatic tissue. The GM-CSF receptor is composed of two subunits, α and β. While the isolated α subunit binds GM-CSF at low-affinity, the isolated β subunit does not bind GM-CSF by itself; but complexes with the α subunit to form a high-affinity receptor. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) showed expression of mRNAs encoding the α and β subunits of the GM-CSF receptor in LNCaP cells, and the presence of the α and β proteins was confirmed by immunolocalization with anti-α and anti-β antibodies. Receptor binding studies using radiolabeled GM-CSF showed that LNCaP cells have about 150 high-affinity sites with a kd of 40 pmol/L and approximately 750 low-affinity sites with a kd of 2 nmol/L. GM-CSF signaled, in a time- and dose-dependent manner, for protein tyrosine phosphorylation and induced the proliferation of the LNCaP cells. Immunolocalization studies showed low level expression of GM-CSF α and β subunits in normal prostate tissue, with substantial expression in benign prostatic hyperplasia and prominent expression in neoplastic prostate tissue. Maximal expression of both subunits was observed in prostatic carcinomas metastatic to lymph node and bone. Tumor cells that stained positively with anti-α subunit antibodies were also reactive with anti-β subunit antibodies, indicating that they express high-affinity GM-CSF receptors. Our data show that the LNCaP cells express functional GM-CSF receptors and that prostatic carcinomas have prominent GM-CSF receptor expression. These findings imply that both hyperplastic and neoplastic prostatic tissues may be responsive to GM-CSF.

Hematopoietic growth factors and treatment of testicular cancer: biological interactions, routine use and dose-intensive chemotherapy

With the use of aggressive cis-platinum-based combination chemotherapy the majority of patients with metastatic testicular cancer will be cured. Hematopoietic growth factors (HGFs), particularly G- and GM-CSF, have been investigated for the treatment of testicular cancer in order to (a) ameliorate chemotherapy-induced myelosuppression, (b) increase the dose intensity of treatment, or (c) generate peripheral blood stem cells (PBSC) as hematopoietic support for mega-dose chemotherapy. Results from in vitro and animal models have excluded a significant influence of both factors, G-CSF and GM-CSF, on tumor growth and response to cytotoxic treatment. For the group of 'good-risk' patients with metastatic testicular cancer, 85-90% of whom will reach long-term survival, the incidence of granulocytopenic infections after standard chemotherapy regimens appears to be lower than 20%. The prophylactic use of HGFs for these patients is not routinely recommended but may be considered in case of an increased risk for infections. For 'poor risk' patients, who will achieve 50% survival following standard chemotherapy, different attempts of treatment intensification have been investigated. The use of aggressive multidrug regimens is associated with granulocytopenic infections in 20-70% of patients. A randomized trial has demonstrated that the prophylactic use of G-CSF significantly reduces granulocytopenia, the number of septic infections, and the infection-related death rate. For 'poor risk' patients the prophylactic use of HGFs, particularly G-CSF due to its favorable side effect profile, is recommended. The availability of G- and GM-CSF has made it possible to develop dose-intensified chemotherapy regimens. Demonstrated particularly for GM-CSF, a 1.5 fold dose increase can be achieved by the use of a myeloid growth factor alone, and thrombocytopenia and other organ toxicity will become dose limiting. Mobilization of PBSC, either after stimulation with HGFs alone or with HGFs, following chemotherapy has been successfully used in patients with testicular cancer. For the treatment of patients with relapsed disease PBSC support followed by HGFs has allowed the use of mega-dose therapy in multiple phase-II studies. This has prompted the investigation of high-dose therapy as first-line treatment for 'poor-risk' patients. In these patients sequential high-dose treatment with cis-platinum, etoposide, and ifosfamide for four consecutive cycles, each supported by G- or GM-CSF and PBSC, is currently being investigated by the German Testicular Cancer Study Group. HGFs have substantially reduced treatment-associated morbidity and mortality in patients receiving chemotherapy for testicular cancer. They make it possible for the first time to clinically explore the true value of dose-intensified chemotherapy regimens in testis cancer, serving as a model of a highly chemotherapy sensitive disease. Enrollment of patients in prospective clinical trials evaluating the role of high-dose therapy is strongly recommended.

Establishment and characteristics of a gastric cancer cell line (HuGC-OOHIRA) producing high levels of G-CSF, GM-CSF, and IL-6: the presence of autocrine growth control by G-CSF

We successfully established a human gastric cancer cell line, HuGC-OOHIRA, from the ascites of a 60-year-old patient with advanced gastric cancer (poorly differentiated adenocarcinoma) complicated by peritonitis carcinomatosa and leukocytosis of unknown origin. Morphologically, the cells were polygonal and adhered weakly to the culture flask. They tended to pile up upon reaching confluence. Chromosome analysis revealed that the cell line has two modes of chromosome number, namely near diploidy and tetraploidy. Double minutes (DMs) were present in abundance in each cell. The doubling time was 25-30 hr. The cell line was successfully transplanted into nude mice, and their peripheral leukocyte counts increased in proportion to the growth of the tumors. At 2 weeks after the transplantation, the serum rG-CSF level was elevated to 2,893 pg/ml. The concentration of human G-CSF in the culture supernatants was an extraordinary high level of 145,380 pg/ml/day. Secretion of GM-CSF and IL-6 was also detected. The intracellular localization of the G-CSF was identified for the first time by immunofluorescence. Moreover, Northern blot analysis detected G-CSF mRNA in this cell line. Anti-recombinant human G-CSF serum suppressed the propagation of HuGC-OOHIRA cell line. Therefore, it is likely that the autocrine growth loop by G-CSF is present in this cell line. This cell line would be very useful for understanding both the cellular and molecular basis for the production of various cytokines such as G-CSF as well as cytokine-dependent tumor proliferation.

Determination of granulocyte/macrophage-colony-stimulating factor secretion by human melanoma cells and its effects on human melanoma cell proliferation

Recently, granulocyte/macrophage-colony-stimulating factor (GM-CSF) became available for overcoming chemotherapy-induced granulocytopenia. GM-CSF not only has a prominent role in the regulation of proliferation and differentiation of haematopoietic cells but it is also secreted by a variety of solid tumours and is capable of exerting growth-stimulatory effects. To evaluate the safety of GM-CSF administration in the treatment of malignant melanoma, we investigated GM-CSF secretion, GM-CSF receptor expression and the effect of GM-CSF on the proliferation of human melanoma cells in vitro. A panel of eight human melanoma cell lines and two fresh tumour specimen was studied. GM-CSF protein was not detectable in culture supernatants by ELISA without stimulation. Interleukin-1 and tumour necrosis factor alpha induced GM-CSF secretion in all four melanoma cell lines tested. When biotinylated GM-CSF was used, the corresponding receptor was not detectable by immunohistochemical or FACScan analysis. The proliferation of eight human melanoma cell lines and two fresh melanoma specimens was determined by the MTT test after 4-6 days of growth in the presence of different concentrations of GM-CSF (0.1-1000 U/ml). Neither proliferation nor growth inhibition was observed. Therefore the effect of GM-CSF on residual tumour cells in vivo may not present a problem during clinical use to stimulate marrow regeneration after or during chemotherapy of metastatic malignant melanoma.

An immunoenzyme technique for the identification of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors using digoxigenated-GM-CSF

A method for detecting granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors has been devised using human macrophages and a GM-CSF/IL-3-dependent human megakaryoblastic leukemia cell line (M-07e). Recognition of the factor-binding site was accomplished by linking recombinant human (rh) unglycosylated GM-CSF previously labeled with digoxigenated compounds. Digoxigenates were able to link amino and sulphydryl groups of the soluble factor and an immunoperoxidase technique using monoclonal anti-digoxigenin antibody was employed to demonstrate the interaction. To support morphological data cross-linking analysis was performed with M-07e cells using digoxigenated-rh-GM-CSF. Macrophages and M-07e cells incubated with digoxigenated-rh-GM-CSF showed intense positivity by the immunoperoxidase technique. In cross-linking, M07e cells showed a 96 kDa band corresponding to receptor plus bound factor. This technique permits a high degree of specificity in the detection of GM-CSF receptors with good morphological preservation of cellular detail.

Identification of a soluble GM-CSF binding protein in the supernatant of a human choriocarcinoma cell line

We identified two forms of the receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) made by the human choriocarcinoma cell line JEG-3 using an affinity-labeling technique. The protein was identified in the detergent-extract was 78 kDa, very similar to that of the membrane-bound GM-CSF receptor alpha chain expressed in a wide variety of hematopoietic and nonhematopoietic cells, including JEG-3. In contrast, a 62-kDa GM-CSF binding protein, or the soluble GM-CSF receptor, was identified in the supernatant of JEG-3 cells. Utilizing the same affinity labeling technique, we did not detect the soluble GM-CSF binding protein in the supernatant of several hematopoietic cell lines, such as U-937 and KG-1, which express membrane bound alpha chain as well as beta chain. The 62-kDa soluble GM-CSF receptor is produced in abundant amounts by JEG-3, but in very small amounts, if any, by hematopoietic cell lines.

Structural and functional analyses of glycosylation on the distinct molecules of human GM-CSF receptors

We have previously demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors are composed of at least two molecules of 80 and 135 kDa, which were denoted alpha- and beta-chains, respectively [Chiba, S., Shibuya, K., Piao, Y.-F., Tojo, A., Sasaki, N., Matsuki, S., Miyagawa, K., Miyazono, K. & Takaku, F. (1990) Cell Regul. 1, 327-335]. In this paper, we describe an investigation of the biochemical disparity noted between the alpha- and beta-chains of GM-CSF receptors using proteolytic and deglycosidic enzymes, and further demonstrate the potential importance of carbohydrate structures of the GM-CSF receptors using different lectins and glycoprotein synthesis inhibitors. Cross-linked alpha- and beta-chains with 125I-GM-CSF were digested by Staphylococcus aureus V8 protease and gave a different pattern. Furthermore, the size of the alpha-chain was reduced by 25 kDa by the removal of the N-linked oligosaccharides with peptidase: N-glycosidase F treatment, whereas that of the beta-chain remained unmodified by the enzyme. These results suggest that the alpha-chain of GM-CSF receptors agrees with the recently cloned low-affinity GM-CSF receptor [Gearing, D.P., King, J.A., Gough, N. M. & Nicola, N.A. (1989) EMBO J. 8, 3667-3676] having approximately 30% N-linked oligosaccharides and is biochemically different from the alpha beta-chain. By analyses using lectins, some of the oligosaccharides in the alpha-chain seem to be the complex-type and/or hybrid-type, because wheat germ agglutinin and leukoagglutinating phytohemagglutinin inhibited both GM-CSF-induced proliferation and GM-CSF binding to its receptors. Further analyses using glycoprotein synthesis inhibitors showed that N-linked processing of the alpha-chain, especially glucose removal by glucosidase I and II (whose activities are inhibited by deoxynojirimycin), appeared to be required for the expression onto the cell surface although the beta-chain expression was little affected by their inhibitors. Thus the beta-chain, probably located near the alpha-chain on the cell surface, was associated with a high-affinity class of GM-CSF receptors.

IL-3 specifically inhibits GM-CSF binding to the higher affinity receptor

The inhibition of binding between human granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor by human interleukin-3 (IL-3) was observed in myelogenous leukemia cell line KG-1 which bore the receptors both for GM-CSF and IL-3. In contrast, this phenomenon was not observed in histiocytic lymphoma cell line U-937 or in gastric carcinoma cell line KATO III, both of which have apparent GM-CSF receptor but an undetectable IL-3 receptor. In KG-1 cells, the cross-inhibition was preferentially observed when the binding of GM-CSF was performed under the high-affinity binding condition; i.e., a low concentration of 125I-GM-CSF was incubated. Scatchard analysis of 125I-GM-CSF binding to KG-1 cells in the absence and in the presence of unlabeled IL-3 demonstrated that IL-3 inhibited GM-CSF binding to the higher-affinity component of GM-CSF receptor on KG-1 cells. Moreover, a chemical cross-linking study has revealed that the cross-inhibition of the GM-CSF binding observed in KG-1 cells is specific for the beta-chain, Mr 135,000 binding protein which has been identified as a component forming the high-affinity GM-CSF receptor existing specifically on hemopoietic cells.

Enhancing effect of ubenimex (bestatin) on proliferation and differentiation of hematopoietic progenitor cells, and the suppressive effect on proliferation of leukemic cell lines via peptidase regulation

Ubenimex (Bestatin) significantly enhanced the G- and GM-CSF-induced colony formation of human bone marrow cells at concentrations of 0.001, 0.01, 0.1 and 1.0 microgram/ml (21-61% enhancement), but not at 10 micrograms/ml. Ubenimex did not influence the EPO-induced erythroid colony and burst formation between 0.0001-100 micrograms/ml. Against human and mouse leukemic cell lines, the growth-inhibitory activities of ubenimex were dose-dependently observed. Aminopeptidase activities on U937 and TF-1 cells were almost inhibited with 10 and 100 micrograms/ml of ubenimex, respectively. Cross-linking studies of 125I-GM-CSF binding to TF-1 cells demonstrated that the 150-kDa band of 2 major bands was enhanced after incubation with 0.01 microgram/ml ubenimex but decreased after that with 100 micrograms/ml, and that the 95-kDa band was not changed at any concentration of ubenimex. Change in density of the 150-kDa band on ubenimex-treated TF-1 cells was correlated with that in expression of CD10 (neutral endopeptidase) on them, whereas that in expression of CD13 (aminopeptidase N) was not changed at any concentration. These results suggest that one possible mechanism of ubenimex action in hematopoietic progenitor cells is the up-regulation of the high affinity receptor for GM-CSF and that in leukemic cell lines is suppression of amino acid incorporation via peptidase regulation.

Expression of granulocyte and granulocyte-macrophage colony-stimulating factors by human non-hematopoietic tumor cells

The expression of granulocyte colony-stimulating factor (G-CSF) mRNA was studied in human non-hematopoietic tumors, including 18 cases of lung cancers 10 cases of stomach cancers, three cases of glioblastomas, and one case each of breast phyllode sarcoma, thyroid cancer, and hepatocellular carcinoma. Northern blot analysis detected G-CSF mRNA in two of the lung cancer cases, in one of the glioblastoma cases, and in both the breast phyllode sarcoma and hepatocellular carcinoma cases. Since G-CSF receptors were not detected on the tumor cells by 125I-G-CSF binding assay, G-CSF autocrine loop are probably not involved in the growth of these G-CSF-producing tumors. Interestingly, granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA was concomitantly expressed in most of these G-CSF-producing tumors. No major gene deletions or rearrangements of G-CSF and GM-CSF genes were demonstrated by Southern blot analysis in the tumors expressing G-CSF and GM-CSF mRNAs except for one of the glioblastomas (G3) in which one chromosome 17 allele was deleted. Although the mechanism of the concomitant expression of G-CSF and GM-CSF mRNA is unknown, relatively high frequency of this phenomenon suggests the presence of common transcriptional factors acting on regulatory regions of G-CSF and GM-CSF genomes.