Effects of cytokines on in vitro colony formation of primary human tumour specimens

Cancer-associated mesenchymal stroma fosters the stemness of osteosarcoma cells in response to intratumoral acidosis via NF-κB activation

The role of mesenchymal stem cells (MSC) in osteosarcoma (OS), the most common primary tumor of bone, has not been extensively elucidated. We have recently shown that OS is characterized by interstitial acidosis, a microenvironmental condition that is similar to a wound setting, in which mesenchymal reactive cells are activated to release mitogenic and chemotactic factors. We therefore intended to test the hypothesis that, in OS, acid-activated MSC influence tumor cell behavior. Conditioned media or co-culture with normal MSC previously incubated with short-term acidosis (pH 6.8 for 10 hr, H⁺ -MSC) enhanced OS clonogenicity and invasion. This effect was mediated by NF-κB pathway activation. In fact, deep-sequencing analysis, confirmed by Real-Time PCR and ELISA, demonstrated that H⁺ -MSC differentially induced a tissue remodeling phenotype with increased expression of RelA, RelB and NF-κB1, and downstream, of CSF2/GM-CSF, CSF3/G-CSF and BMP2 colony-promoting factors, and of chemokines (CCL5, CXCL5 and CXCL1), and cytokines (IL6 and IL8), with an increased expression of CXCR4. An increased expression of IL6 and IL8 were found only in normal stromal cells, but not in OS cells, and this was confirmed in tumor-associated stromal cells isolated from OS tissue. Finally, H⁺ -MSC conditioned medium differentially promoted OS stemness (sarcosphere number, stem-associated gene expression), and chemoresistance also via IL6 secretion. Our data support the hypothesis that the acidic OS microenvironment is a key factor for MSC activation, in turn promoting the secretion of paracrine factors that influence tumor behavior, a mechanism that holds the potential for future therapeutic interventions aimed to target OS.

Cancer biology and hormesis: human tumor cell lines commonly display hormetic (biphasic) dose responses

This article assesses the nature of the dose-response relationship of human tumor cell lines with a wide range of agents including antineoplastics, toxic substances (i.e., environmental pollutants), nonneoplastic drugs, endogenous agonists, and phyto-compounds. Hormetic-like biphasic dose responses were commonly reported and demonstrated in 136 tumor cell lines from over 30 tissue types for over 120 different agents. Quantitative features of these hormetic dose responses were similar, regardless of tumor cell line or agent tested. That is, the magnitude of the responses was generally modest, with maximum stimulatory responses typically not greater than twice the control, while the width of the stimulatory concentration range was usually less than 100-fold. Particular attention was directed to possible molecular mechanisms of the biphasic nature of the dose response, as well as clinical implications in which a low concentration of chemotherapeutic agent may stimulate tumor cell proliferation. Finally, these findings further support the conclusion that hormetic dose responses are broadly generalizable, being independent of biological model, endpoint measured, and stressor agent, and represent a basic feature of biological responsiveness to chemical and physical stressors.

Tumor skewing of CD34+ progenitor cell differentiation into endothelial cells

Tumor production of granulocyte-macrophage colony-stimulating factor (GM-CSF) results in the mobilization of CD34(+) progenitor cells into the peripheral blood and tumor tissue. Using the Lewis lung carcinoma (LLC) model, in vitro studies showed that LLC cells could chemoattract CD34(+) cells predominantly through tumor production of VEGF. Addition of LLC-conditioned medium to CD34(+) cells that were cultured under conditions that support myeloid lineage cells skewed the differentiation of these precursor cells toward endothelial cells expressing CD31 and CD144. This differentiation of CD34(+) cells toward endothelial cells was attributed predominantly to angiopoietin-1 in the tumor-conditioned medium. The CD34(+) cells expressed the angiopoietin receptor Tie-2 and their differentiation into endothelial cells was blocked with neutralizing angiopoietin-1 antibodies. In vivo studies showed that infusion of lacZ(+) CD34(+) cells from the bone marrow of transgenic mice into wild-type mice bearing LLC tumors resulted in the accumulation of lacZ(+) cells within the tumor mass, particularly at the tumor's periphery. That these infused CD34(+) progenitor cells could develop into endothelial cells of the tumor vasculature was supported by their acquisition of the endothelial cell markers CD31 or CD144 within the tumor tissue. These studies demonstrate the capacity of tumor to attract CD34(+) cells to the tumor site and to direct the differentiation of these CD34(+) cells into endothelial cells that can become a component of the tumor vasculature.

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.

Human squamous cell carcinomas of the head and neck chemoattract immune suppressive CD34(+) progenitor cells

CD34(+) progenitor cells have previously been shown to be mobilized in patients with squamous cell carcinoma of the head and neck (HNSCC). The present study showed that these CD34(+) cells inhibit the capacity of intratumoral lymphoid cells to become activated in response to stimulation through the TCR/CD3 complex. The mechanisms that could lead to the accumulation of CD34(+) cells within the tumor tissue were assessed. This was accomplished through in vitro studies that determined if HNSCC produce soluble factors that chemoattract CD34(+) cells. The migration of cord blood CD34(+) cells, which were used as a readily available source of progenitor cells, was stimulated by products derived from HNSCC explants and primary HNSCC cultures. This stimulated migration was due to chemotaxis because it was dependent on an increasing gradient of HNSCC-derived products. CD34(+) cells that were isolated from the peripheral blood of HNSCC patients were similarly chemoattracted to the HNSCC-derived products. The majority of the chemotactic activity produced by HNSCC could be attributed to vascular endothelial cell growth factor (VEGF). These studies indicate that HNSCC can chemoattract immune inhibitory CD34(+) progenitor cells through their production of VEGF.

Chemoattraction of femoral CD34+ progenitor cells by tumor-derived vascular endothelial cell growth factor

Patients and animals with GM-CSF-producing tumors have an increased number of mobilized CD34+ progenitor cells within their peripheral blood and tumor tissue. These CD34+ cells are inhibitory to the activity of intratumoral T-cells. The present study used the murine Lewis lung carcinoma (LLC) model to assess mechanisms that could lead to the accumulation of CD34+ cells within the tumor tissue. In vitro analyses showed that LLC tumor explants released chemoattractants for normal femoral CD34+ cells. The LLC tumor cells contributed to the production of this activity since CD34+ cell chemoattractants were also released by cultured LLC cells. Antibody neutralization studies showed that most, although not all, of the chemotactic activity that was produced by LLC cells could be attributed to VEGF. In vivo studies with fluorescent-tagged CD34+ cells showed their accumulation within the tumor tissue, but not within the lungs, spleen or bone marrow, suggesting a selective accumulation within the tumor. Whether or not VEGF could chemoattract CD34+ cells in vivo was measured with a VEGF-containing Matrigel plug assay. Infusion of fluorescent-tagged CD34+ cells into mice after the plugs became vascularized revealed the accumulation of fluorescent-tagged cells within the plugs. However, these CD34+ cells failed to accumulate within the VEGF-containing Matrigel plugs when they were infused together with neutralizing anti-VEGF antibody. Through a combination of in vitro and in vivo analyses, the LLC cells were shown to be capable of chemoattracting CD34+ cells, with most of the tumor-derived chemotactic activity being due to tumor release of VEGF.

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.

Mechanisms of immune suppression in patients with head and neck cancer: influence on the immune infiltrate of the cancer

Freshly excised human head and neck cancers (219 primary cancers; 64 metastatic lymph node cancers) were analyzed for the immune inhibitory mediators released from the cancer tissues and the immune infiltrate within the tumor. Significant levels of the immune inhibitory mediators transforming growth factor-beta (TGF-beta), prostaglandin E2 (PGE2) and interleukin-10 (IL-10) were released from these cancers. Also released was granulocyte-macrophage colony-stimulating factor (GM-CSF), whose secretion was associated with an intratumoral presence of CD34+ cells. We have previously shown that CD34+ cells within human head and neck cancers are immune inhibitory granulocyte-macrophage progenitor cells. The presence of TGF-beta, PGE2 and IL-10 was associated with a reduced content of CD8+ T-cells within the cancers. The CD4+ cell content appeared to be less affected by these immune inhibitory mediators. Instead, parameters indicative of CD4+ cell function (p55 IL-2 receptor expression, release of IL-2 and IFN-gamma) were diminished in cancers that released higher levels of TGF-beta, IL-10 and GM-CSF and had a higher CD34+ cell content. Furthermore, metastatic cancers released higher levels of the soluble immune inhibitory mediators and lower levels of IFN-gamma and IL-2 than did primary cancers, although CD34+ cells were similarly present in both primary and metastatic cancers. Our results show that human head and neck cancers have a multiplicity of non-mutually exclusive mechanisms of immune suppression that are most prominently associated with reduced CD8+ cell influx and reduced influx and altered function of intratumoral CD4+ cells.

Vitamin D3 treatment of tumor bearers can stimulate immune competence and reduce tumor growth when treatment coincides with a heightened presence of natural suppressor cells

By secreting granulocyte-macrophage colony-stimulating factor (GM-CSF), Lewis lung carcinoma tumors induce immune suppressive granulocyte-macrophage progenitor cells. Treating mice having established tumors and high levels of suppressor activity with vitamin D3 eliminated suppressor activity, increased anti-tumor immunity, induced an immune stimulatory cell population, and reduced tumor growth. When instead, the vitamin D3 treatment was initiated earlier, when implanted tumors first became detectable and when natural suppressor activity was less prominent, the treatment had no effect. Thus, vitamin D3 treatment can stimulate the immune competence of tumor bearers when treatment is targeted to coincide with a heightened presence of GM-CSF-induced suppressor cells.

Granulocyte-macrophage colony-stimulating factor accelerates growth of Lewis lung carcinoma in mice

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has not been found to exert any influence on the proliferation of Lewis lung carcinoma (LLC) cells in vitro. Nevertheless, when administered intraperitoneally, GM-CSF accelerated the growth of subcutaneously growing LLC in mice.

Growth modulatory effects of granulocyte-macrophage colony-stimulating factor on human cell lines derived from gynecologic malignancies

OBJECTIVE

In spite of increased expression of granulocyte-macrophage colony-stimulating factor surface receptors on solid tumors, the growth modulatory effects of granulocyte-macrophage colony-stimulating factor have not been well defined in gynecologic malignancies. We assessed the in vitro growth effects of granulocyte-macrophage colony-stimulating factor on such cell lines.

STUDY DESIGN

By use of a chromium 51 incorporation assay the in vitro growth effects of granulocyte-macrophage colony-stimulating factor on 12 cell lines derived from human malignancies were measured.

RESULTS

No growth stimulatory or inhibitory effect was mediated by granulocyte-macrophage colony-stimulating factor on six cell lines, whereas three lines showed consistent but not statistically significant dose-dependent growth stimulation. There was, however, a statistically significant increase in growth of short duration in three other cell lines at clinically relevant doses of granulocyte-macrophage colony-stimulating factor. Fluorometric cell cycle analysis demonstrated no change in cell-cycle distribution.

CONCLUSION

Within this in vitro system, stimulation of gynecologic malignancies in patients receiving granulocyte-macrophage colony-stimulating factor for mitigation of the myelosuppressive effects of cytotoxic chemotherapy does not appear to be widespread nor sustained beyond 48 hours.

Recombinant human stem cell factor does exert minor stimulation of growth in small cell lung cancer and melanoma cell lines

We have previously reported on the stimulation of clonal growth of a glioblastoma cell line by rhSCF (Berdel et al., Cancer Res 1992, 52, 3498-3502). Within an extensive screening programme of haematopoietic growth factor activity on malignant cells, the effects of rhSCF were further tested on the growth of 29 different human cell lines derived from a wide range of solid tumours, among them six lung cancers and five melanomas. RhSCF (0, 1, 10, 100 ng/ml) was tested in a human tumour cloning assay (HTCA) which reliably detects growth modulation of tumour cells by cytokines. Additionally, a tritiated thymidine uptake test was used. Growth of 27 of the 29 cell lines tested was not affected by rhSCF. However, growth of the small cell lung cancer (SCLC) cell line HTB 120 was slightly stimulated (1.5 fold that of controls), and that of the melanoma cell line MeWo was stimulated up to 1.3-fold. This activity was eliminated dose-dependently by the tyrosine kinase inhibitor, genistein. We further analysed the cell lines for expression of the proto-oncogene C-KIT and its ligand SCF. All melanoma and lung cancer cell lines expressed SCF as assessed at the mRNA level. Northern blotting also revealed clear C-KIT mRNA expression in three melanoma (HAS, MeWo, SK-MEL-28), one NSCLC (HTB 53), and four SCLC cell lines (HTB 119, HTB 120, HTB 171, HTB 175). Furthermore, C-KIT protein expression was detected by flow cytometric analysis on the cell surface of MeWo, HTB 119 and HTB 120 cells. Our data indicate that SCF can be operative in growth modulation of non-haematopoietic malignant cells, especially SCLC and melanoma. However, our extensive screening of SCF/tumour cell interaction shows that this interaction is rare and makes potential hazards, such as tumour stimulation upon clinical use of rhSCF in conjunction with chemotherapy in cancer patients, unlikely for the majority of other tumour histologies.

Effects of the hematopoietic growth factors GM-CSF, IL-3, and IL-6 on human tumor colony-forming units taken directly from patients

BACKGROUND

One concern regarding the use of hematopoietic growth factors (e.g., GM-CSF, IL-3, and IL-6) to accelerate hematologic recovery after treatment of solid tumors with high doses of chemotherapy is that these factors may stimulate tumor growth.

MATERIALS AND METHODS

We tested the effects of GM-CSF, IL-3 or IL-6 (continuous exposure to 1, 10, and 100 ng/ml of each cytokine) on tumor cells taken directly from patients with solid tumors using the human tumor cloning assay. The range of concentrations of the cytokines used in our study included the concentrations that appear to be clinically relevant.

RESULTS

Of the evaluable samples, stimulation of tumor growth was noted in 0/16 exposed to GM-CSF, in 3/72 (4%) exposed to IL-3, and in 1/65 (2%) exposed to IL-6. Inhibition of tumor proliferation was noted in no sample exposed to GM-CSF, in 7 (10%) exposed to IL-3 and in 7 (10%) exposed to IL-6.

CONCLUSIONS

The use of GM-CSF, IL-3 or IL-6 to reduce myelosuppression after high dose chemotherapy appears unlikely to result in stimulation of the growth of the most common solid tumors. It is also unlikely that either IL-3 and IL-6 alone will be useful as antitumor agents against solid tumors.

Effects of interleukin-3 following chemotherapy of non-Hodgkin's lymphoma. A prospective, controlled phase I/II study

The effect of rhIL-3 was investigated in 32 patients with newly diagnosed non-Hodgkin lymphoma in a phase I/II trial. All patients received 6 cycles of standard CHOP chemotherapy, and each patient was his own control where rhIL-3 was given as a daily s.c. injection for 14 days (day 2-15) in cycle 2 and 4, while cycle 1 and 3 were control cycles. Five dose levels were examined (0.5 - 1 - 5 - 7.5 - 10 micrograms/kg). Compared to the other more lineage-specific hemopoietic growth factors G- and GM-CSF, the effect of rhIL-3 on the hemopoiesis was less dramatic and more delayed, i.e. the most apparent effect was observed in the 2 weeks of treatment. Thus, the neutrophil counts from days 15 to 22 following CHOP were significantly raised and the duration of neutropenia was shorter (significantly only at 10 micrograms/kg), while the nadir values were unaffected. Platelet recovery from days 12-22 was significantly increased and nadir values occurred earlier compared to control cycles, but were only increased in some subsets. Other cell populations affected moderately in the recovery period were eosinophils and monocytes. Reticulocytes increased, but no effect on hemoglobin or RBC transfusion requirement was noted. Only moderate adverse reactions occurred such as fever, chills, flushing of the face and flu-like symptoms. There was no evidence of stimulation of tumor growth. Most significant, the rhIL-3 treatment at all but the lowest dose levels led to an improved tolerance to chemotherapy, as indicated by a decline in number of delayed cycles. A conclusion concerning the role of rhIL-3 as post-chemotherapy adjuvant should await studies using rhIL-3 in combination with more lineage-restricted hemopoietic growth factors.

Direct and indirect effects of recombinant human granulocyte-colony stimulating factor on in vitro colony formation of human bladder cancer cells

Although the present experimental use of recombinant human granulocyte-colony-stimulating factor (rG-CSF) has been proven to alleviate the myelosuppression induced by antitumor chemotherapy, it is also believed to stimulate growth of some nonhematopoietic tumor cells. We investigated both the direct and indirect effects of rG-CSF on in vitro colony formation of human bladder cancer cell lines using a modified human tumor clonogenic assay. Peripheral blood mononuclear cells (PBMC) were used as feeder cells (a mixture of 5 x 10(4) monocytes/dish and 5 x 10(5) lymphocytes/dish obtained from healthy donors). Human bladder cancer cell lines KK-47, TCCSUP and T24, all derived from human transitional-cell carcinomas, were incubated continuously with various concentrations of rG-CSF ranging from 0.01 ng/ml to 10 ng/ml both with and without PBMC for 7-21 days. The concentrations of rG-CSF used were chosen as being in the range of achievable serum concentrations in patients treated with rG-CSF. At the end of incubation, colonies were counted under an inverted phase-contrast microscope, and an increase in the number of colonies in comparison with the control was used to evaluate the effects of rG-CSF. Results were expressed as a percentage of controls. rG-CSF in the upper layer at concentrations ranging from 0.1 ng/ml to 10 ng/ml stimulated the colony formation of all the cancer cell lines tested in the absence of PBMC in the feeder layer, whereas cells with PBMC in the feeder layer were significantly stimulated more than those without PBMC in the feeder layer (P < 0.05) up to a certain concentration, which varied from cell line to cell line. At higher concentrations of rG-CSF, no further stimulation but, on the contrary, a decrease in colony formation was observed in cells with PBMC in the feeder layer in all the cell lines tested. Colony formation in KK-47 and T24 cell lines was significantly inhibited at 5 ng/ml and/or 10 ng/ml rG-CSF compared with cells without PBMC in the feeder layer. Our results suggest that rG-CSF may have both direct and indirect stimulatory effects on the growth of human bladder cancer cell lines in vitro. The results obtained also raise the possibility of adverse effects of rG-CSF in bladder cancer patients whose malignant cells may be directly and indirectly stimulated by this factor while it is being used clinically to alleviate the myelosuppression induced by antitumor chemotherapy.

Granulocyte-macrophage colony-stimulating factor stimulates the metastatic properties of Lewis lung carcinoma cells through a protein kinase A signal-transduction pathway

Expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) by metastatic Lewis lung carcinoma cells (LLC-LN7) was previously shown to contribute to the maintenance of phenotypic characteristics associated with an increased capacity to metastasize. In the present study, pre-incubation of LLC-LN7 cells with neutralizing anti-GM-CSF antibodies diminished the capacity of the tumor cells to form experimental metastases after i.v. inoculation, while pre-incubation with recombinant GM-CSF (rGM-CSF) increased formation of metastases. In the presence of rGM-CSF, the LLC-LN7 cells exhibited an increased capacity to migrate, invade through a reconstituted basement membrane, and adhere to lung tissue. Studies to identify the signal transduction pathway through which GM-CSF enhanced the in vitro metastatic properties of the LLC-LN7 tumor cells implicated protein kinase A (PKA). Signaling through PKA was suggested by the demonstration that the stimulation of tumor-cell motility by GM-CSF was blocked in the presence of the adenylate cyclase inhibitor nicotinic acid, or the PKA inhibitors A3 or KT5720. In addition, the role of PKA as a signaling mechanism for GM-CSF was assessed by using REV-LN7 cells, which are LLC-LN7 cells that have been stably transfected with an expression vector encoding a mutant PKA RI alpha subunit and which, in turn, express a cAMP-resistant PKA. Adherence and invasion by the PKA-defective REV-LN7 cells were not stimulated by rGM-CSF, contrasting with the stimulation observed for wild-type LLC-LN7 cells. These data suggest that rGM-CSF can further enhance the in vitro metastatic characteristics of LLC-LN7 tumor cells and that this is dependent on signal transduction through PKA.

Effects of cytokines on growth in vitro of primary human renal cell carcinoma

In clinical trials different haematopoietic active cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) have been proven to alleviate myelosuppressive side effects of intensive chemotherapy in different non-urological malignancies. On the other hand, these cytokines can directly stimulate the proliferation of cells originating from some non-urological tumours. To clarify the impact of these cytokines on the proliferative behaviour of human renal cell carcinoma (RCC), 29 previously untreated RCC tumours were prepared for culturing in vitro using the cell cluster technique. The success rate for growth in vitro was 82.8% (24/29). The malignant renal cells were treated with different cytokines (GM-CSF, G-CSF and interleukin-3) in different dosages. Cell number and proliferation rates detected by immunostaining were used for treatment evaluation. A dosage-dependent stimulation of cell growth could not be observed compared to untreated cells. From the data presented in this study, proliferative stimulation of RCC by administering colony-stimulating factors in clinical trials cannot be assumed.

Effect of interleukin-3 and granulocyte-macrophage colony-stimulating factor on growth of xenotransplanted human tumour cell lines in nude mice

The clonal growth of cell lines from some human solid tumours can be stimulated by haematopoietic growth factors such as recombinant human (rh) interleukin-3 (IL-3) and rh granulocyte-macrophage colony-stimulating factor (GM-CSF) in vitro. Among these cell lines are the human colorectal adenocarcinoma cell line HTB 38 and the human small-cell lung cancer cell line HTB 119. Here we report on a series of experiments studying the influence of subcutaneously administered rhIL-3 and rhGM-CSF on the in vivo growth of HTB 38 and HTB 119 cell lines as xenografts in athymic nu/nu BALB/c mice. Beginning 1 day after transplantation of the tumour the cytokines were administered daily for 20 days as a subcutaneous bolus distant from the tumour lesion at dose levels up to 1 mg/m2/day. The cytokines caused no significant and reproducible growth modulation of the tumours in vivo.

The Florey Lecture, 1991. The colony-stimulating factors: discovery to clinical use

The four colony-stimulating factors, GM-GSF, G-CSF, M-CSF and Multi-CSF, are specific glycoproteins with a likely common ancestral origin which interact to regulate the production, maturation and function of granulocytes and monocyte-macrophages. Each has been purified and produced in active recombinant form. Animal studies have shown the ability of injected CSF to increase the production and functional activity of granulocytes and macrophages in vivo and to enhance resistance to infections. These studies have led to the current extensive clinical use of CSFs to promote the formation and function of granulocytes and macrophages in a wide variety of disease situations in which there is an associated risk of serious infections. Although our knowledge of the control of haemopoiesis remains incomplete, the approaches used to develop the CSFs can be used to extend this knowledge, with the promise of the introduction into clinical medicine of additional effective therapeutic agents.