Hematopoietic growth factors in cancer

Elastophagocytosis: A Clue to the Diagnosis of GM-CSF-Induced Dermatosis

Background:

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine used to stimulate the production of leukocytes and monocytes in neutropenic patients. Cutaneous reactions to GM-CSF are relatively common. However, documentation of the histologic features of GM-CSF-induced dermatoses has only been reported in nine patients. We previously reported three patients with GM-CSF dermatoses, all of whom demonstrated enlarged macrophages in the dermis. Biopsies from two of the patients showed intracytoplasmic elastin fragments in dermal macrophages consistent with GM-CSF's documented ability to increase phagocytic activity of macrophages in vitro.

Objective:

The objective of the present report is to present an additional case of GM-CSF-induced dermatoses and to document the apparent ability of this cytokine to induce phagocytosis of elastin fragments by macrophages.

Methods and Results:

The patient received GM-CSF to stimulate bone marrow recovery after a bone marrow transplant. He developed a diffuse macular papular rash that on biopsy revealed enlarged dermal macrophages with prominent intracytoplasmic elastin fragments.

Conclusions:

Elastophagocytosis by activated macrophages is a common finding in GM-CSF-induced dermatoses and is a relatively specific clue to the diagnosis of this disorder.

Regulation of granulocyte and macrophage populations of murine bone marrow cells by G-CSF and CD137 protein

Background

Granulocytes and monocytes/macrophages differentiate from common myeloid progenitor cells. Granulocyte colony-stimulating factor (G-CSF) and CD137 (4-1BB, TNFRSF9) are growth and differentiation factors that induce granulocyte and macrophage survival and differentiation, respectively. This study describes the influence of G-CSF and recombinant CD137-Fc protein on myelopoiesis.

Methodology/Principal Findings

Both, G-CSF and CD137 protein support proliferation and survival of murine bone marrow cells. G-CSF enhances granulocyte numbers while CD137 protein enhances macrophage numbers. Both growth factors together give rise to more cells than each factor alone. Titration of G-CSF and CD137 protein dose-dependently changes the granulocyte/macrophage ratio in bone marrow cells. Both factors individually induce proliferation of hematopoietic progenitor cells (lin^-, c-kit⁺) and differentiation to granulocytes and macrophages, respectively. The combination of G-CSF and CD137 protein further increases proliferation, and results in a higher number of macrophages than CD137 protein alone, and a lower number of granulocytes than G-CSF alone demonstrating that CD137 protein-induced monocytic differentiation is dominant over G-CSF-induced granulocytic differentiation. CD137 protein induces monocytic differentiation even in early hematopoietic progenitor cells, the common myeloid progenitors and the granulocyte macrophage progenitors.

Conclusions/Significance

This study confirms earlier data on the regulation of myelopoiesis by CD137 receptor - ligand interaction, and extends them by demonstrating the restriction of this growth promoting influence to the monocytic lineage.

Two pathways of apoptosis induced with all-trans retinoic acid and etoposide in the myeloid cell line P39

P39/Tsugane is a myelomonocytoid cell line derived from a patient with myelodysplastic syndrome (MDS). The cells readily undergo apoptosis in response to various agents, and the cell line has been suggested as a useful model to study apoptosis in MDS. The aims of the present study were to assess differentiation and apoptosis induced with all-trans retinoic acid (ATRA) and etoposide, to characterize the mode of apoptosis in these two model systems, and to assess the influence of granulocyte colony-stimulating factor (G-CSF), which in combination with erythropoietin has been shown to inhibit apoptosis in MDS. ATRA induced differentiation and apoptosis in a concentration- and time-dependent manner. Differentiated cells were partially rescued (by 50%) from apoptosis with G-CSF. Etoposide induced apoptosis in a concentration- and time-dependent manner, but no signs of preceding maturation or G-CSF rescue were detected. ATRA- and etoposide-induced apoptosis were both mediated through the caspase pathway and were partially blocked with the general caspase inhibitor zVAD-fmk. Simultaneous treatment with G-CSF and zVAD-fmk additively blocked ATRA-induced apoptosis. However, the two pathways differed in terms of substrate cleavage during apoptosis. ATRA-induced apoptosis caused actin cleavage, which was not affected by G-CSF, and Bcl-2 downregulation. Etoposide induced a caspase-dependent cleavage of Bcl-2, while actin remained intact. The Fas system did not seem to play a major role in any of these apoptotic pathways. Our results may provide new tools to study the mechanisms of apoptosis in MDS.

Development of a recombinant growth factor and fusion protein: lessons from GM-CSF

Several colony stimulating factors (CSFs) and cytokines have been successfully used to mobilize hematopoietic cells during myeloablative therapy, bone marrow failure, and transplantation and to provide supportive treatment during sepsis. The use of yeast-derived recombinant human granulocyte-macrophage CSF (rhuGM-CSF) and its interleukin-3 fusion protein, PIXY321, provides an example of issues associated with development programs for recombinant hematopoietic growth factors. Species specificity of rhuGM-CSF, different bioactivity of homologous molecules in mice, and production in laboratory animals of antibodies to human proteins limit preclinical evaluation of such molecules. In clinical trials, rhuGM-CSF was efficacious and well tolerated. The derivation of the recombinant molecule, optimal dosing, scheduling, and confounding effects of concurrent disease and treatments are factors that influence efficacy, adverse responses, and immunogenicity reported in patients treated with CSFs. In comparisons of yeast-derived with Escherichia coli-derived rhuGM-CS, the reduced severity and frequency of all adverse events, preponderance of low-grade adverse events, and similarity of positive clinical response versus adverse events reported for granulocyte CSF support safety and efficacy of yeast-derived rhuGM-CSE Enhanced pharmacoeconomic evaluations are beginning to limit and redirect clinical applications in this class of biological agents.

Bone marrow uptake of fluorine-18-fluorodeoxyglucose following treatment with hematopoietic growth factors: initial evaluation

Hematopoietic growth factors (HGF) such as G-CSF and GM-CSF stimulate cell growth of the bone marrow and thereby mitigate the myelotoxic effect of chemotherapy. Using 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) for therapy response monitoring of patients with small-cell lung cancer, both an extension and an intensification of thoracic bone marrow uptake were noted in patients treated with HGF (n = 5) compared to those patients without HGF supplementation (n = 11). FDG uptake was a very sensitive marker of stimulated hematopoiesis, and both the extension and the intensification of uptake have to be noted during HGF therapy.

Recombinant human interleukin-3 induces extramedullary hematopoiesis at subcutaneous injection sites in cynomolgus monkeys

Parenteral administration of recombinant hematopoietic growth factors has been sporadically associated with cutaneous complications, including injection site reactions in humans and nonhuman primates. In this study, subcutaneous injection sites were evaluated from 12 cynomolgus monkeys administered a recombinant human interleukin-3 (rhIL-3) at dose levels of 0, 70, or 700 micrograms/kg daily for 18 days. Monkeys administered rhIL-3 developed small (0.5-1-cm-diameter), firm nodules at the subcutaneous injection sites. Histologically, these nodules from 4 of 8 rhIL-3-treated monkeys contained trilineage extramedullary hematopoiesis (EMH) represented by precursors of myeloid, erythroid, and megakaryocytic series cells. The lineage of hematopoietic cells was confirmed by histochemical and immunohistochemical methods. Hematopoietic cells of myeloid and megakaryocytic lineages were more common than erythroid cells. Of myeloid cells, immature eosinophils were more common, which usually formed small sheets or clusters in the panniculus and deep dermis. This report describes, for the first time, the occurrence of cutaneous EMH at the injection sites of recombinant hematopoietic growth factors, which should be differentiated from inflammation. We believe the cutaneous EMH was the exaggerated pharmacologic effect of rhIL-3.

Production and response of human prostate cancer cell lines to granulocyte macrophage-colony stimulating factor

Prostate cancer selectively metastasises to skeletal sites, where it normally produces osteoblastic lesions. This study investigated whether haematopoietic growth factors known to be present in the bone environment could be involved in the survival and proliferation of prostate skeletal metastases. To evaluate this hypothesis we investigated the effects of recombinant granulocyte/macrophage colony-stimulating factor (rGM-CSF), recombinant granulocyte colony-stimulating factor (rG-CSF), recombinant erythropoietin (rEPO) and recombinant interleukin-3 (rIL-3) on the growth of 3 human prostate cancer cell lines. Two hormone-insensitive cell lines, PC-3 and DU145, were significantly stimulated by rGM-CSF and rEPO in serum-free medium but their growth was unaffected by incubation with rIL-3 or rG-CSF. A hormone-sensitive cell line, LNCaP, was stimulated only by rGM-CSF. To investigate further the involvement of GM-CSF in prostate cancer, the presence of GM-CSF protein in the 3 prostate cancer cell lines was examined by immunohistochemistry, and analysis of cell line conditioned media was carried out by ELISA and Western blotting. These techniques demonstrated that GM-CSF-like material was produced by both DU145 and PC-3 cells but not by LNCaP. The results from ELISA found that media conditioned by DU145 and PC-3 cells contained 1.7 and 2.5 pg GM-CSF/micrograms protein, respectively, whereas no GM-CSF was detectable in the LNCaP conditioned media. Our results were also confirmed by Western blot analysis demonstrating one single band for DU145 and PC-3 conditioned media which co-migrated along with the standard rGM-CSF band. No bands were associated with the LNCaP conditioned media. The presence of GM-CSF gene transcripts in DU145 and PC-3 cells was established by reverse transcription and polymerase chain reaction of total RNA.

Bone marrow myeloid cell kinetics during treatment of small cell carcinoma of the lung with chemotherapy not associated and associated with granulocyte-macrophage colony-stimulating factor

Information on the kinetics of bone marrow (BM) myeloid precursors (BMMP) is required for integrating cancer chemotherapy with granulocyte-macrophage colony-stimulating factor (rhGM-CSF), with the aim of reducing neutropenia. Using bivariate flow-cytometric analysis of the in vivo incorporation of bromode-oxyuridine (BUDR) vs DNA content we have studied the kinetics of BMMP in 21 patients with SCLC during the first of six chemotherapy courses (etoposide, epirubicin, and cis-platinum, days 1-3, every 21 days), given alone (eight patients) or followed by rhGM-CSF (10 micrograms/kg/day s.c., days 4-14) as BM rescue (eight patients) or both preceded (days -17 to -7, as BM priming) and followed by rhGM-CSF (five patients). At 11-14 days after the start of these therapies there was an increase in the baseline proliferative activity of proliferating BMMP and a shortening in the time needed by the metamyelocyte to mature and to leave the marrow. Both effects were greater and were maintained to a significantly greater degree a week later in patients who received chemotherapy plus rhGM-CSF rescue than in those who received chemotherapy alone or rhGM-CSF priming alone. At day 11-14 the pretreatment median cell production rate of pBMMP was increased by 340%, 150%, and 183% and the maturation time was reduced by 80%, 45%, and 57%, respectively, in the three groups. A week later, the corresponding figures were 206%, 111%, and 157% and 50%, 18%, and 45%. Hence, an identical rhGM-CSF schedule is more effective in increasing the neutrophil production by BMMP when given following chemotherapy as BM rescue than before it as BM priming. In both the rescue and the priming schedule, the increase in proliferative activity of BMMP just at the end of rhGM-CSF stimulation was linked to both an increase in the labeling index and a reduction in duration of S-phase (TS), while a week later it was linked solely to reduction in TS. This could actually reduce one of the two kinetic targets of subsequently administered cytostatics, i.e., a high LI and a long time spent in S phase. From this study, accurate kinetic data can be obtained with the in vivo BUDR technique that are useful in scheduling rhGM-CSF.

Tumor cell dissemination triggers an intrathecal immune response in neoplastic meningitis

The intrathecal immune response in neoplastic meningitis (NM) was studied by quantitation of immune parameters such as immunoglobulin G (IgG); IgM; interleukins (IL) 1, 2, 4, and 6; soluble IL-2 receptors (sIL-2R); interferon gamma (IFNy); tumor necrosis factor-alpha (TNF alpha); and three tumor markers, carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), and fibronectin (FN), in 47 paired cerebrospinal fluid (CSF) and serum samples from patients with NM from different carcinomas, malignant melanoma, and lymphoma. Elevated IgG and IgM indices, CSF oligoclonal Ig bands, and CSF IL-6 indicated an intrathecal immune activation in most patients with NM. Results for IL-1, IL-2, and IL-4 were always negative. sIL-2R and IFNy were detected occasionally but not associated with specific malignant neoplasms. CSF TNF alpha was detected only in NM from cases of malignant melanoma. None of the immune parameters proved useful for the differentiation of NM from autoimmune or inflammatory conditions. Immune parameters were not correlated with tumor markers CEA, AFP, or FN. Results for AFP were positive only in a case of glioblastoma. CEA was a useful and specific diagnostic parameter in carcinomatous NM. CSF FN levels frequently were elevated but are not specific for NM.

Stimulation of the metastatic properties of Lewis-lung-carcinoma cells by autologous granulocyte-macrophage colony-stimulating factor

Using both polymerase-chain-reaction analysis and the soft-agar colony-forming unit assay, granulocyte-macrophage colony-stimulating factor (GM-CSF) was shown to be expressed by cloned metastatic Lewis-lung-carcinoma (LLC-LN7) cells but not by non-metastatic LLC-C8 cells. Furthermore, the metastatic LLC-LN7 cells were shown to respond both to autologous GM-CSF and to exogenous recombinant GM-CSF (rGM-CSF). In the presence of neutralizing anti-GM-CSF antibodies, the metastatic LLC cells became less able to migrate or to adhere and invade through a reconstituted basement membrane. Moreover, the addition of rGM-CSF further enhanced the capacity of the metastatic LLC cells to adhere to the reconstituted basement membrane. This stimulation of metastatic properties of the LLC cells by either autologous or exogenous GM-CSF was associated with enhanced endogenous protein phosphorylation. Two proteins of approximately Mr 45,000 and Mr 64,000 were the dominant target proteins to be phosphorylated by the presence of GM-CSF. These results suggest that autologous GM-CSF may function as an autocrine stimulator of the metastatic properties of metastatic LLC cells.

Acute myeloid leukemia in the elderly: biological features and search for adequate treatment

AML in elderly patients is a heterogeneous disease which is characterized by a number of unfavorable features such as development, cytogenetics, blast cell differentiation, and poor treatment response. Specifically, the association between a higher incidence of unfavorable cytogenetic abnormalities in elderly patients and poor prognosis has been well documented. Low treatment response may be due to the specific biology of AML in this patient group, but also to host-specific factors such as higher treatment-related morbidity and mortality. Treatment tolerance cannot be judged on grounds of chronological age alone; risk factor analysis with regard to performance status, organ function, and underlying systemic disease need to be considered as well. For effective induction treatment in elderly patients, instant and intensive chemotherapy appears to be necessary, while delayed treatment or administration of supportive care alone provide unsatisfactory results. Standard-dose ara-C/anthracycline-containing regimens are the treatment of choice in patients with good performance status. However, patients with a WHO grading of greater than 3 might rather benefit from reduced regimens such as low-dose ara-C. At present, greatest improvement of AML treatment in elderly patients can be expected from an improvement of supportive care.