Effects of myeloproliferative sarcoma virus on the pluripotential stem cell and granulocyte precursor cell populations of DBA/2 mice.

The hematopoietic stem cell (CFU-S) and granulocyte precursor cell (CFU-C) populations have been assayed in the spleen, blood, and bone marrow of DBA/2 mice at various times after infection with the myeloproliferative sarcoma virus (MPSV). Beginning between 7 and 19 days after virus infection, the number of CFU-S showed a steady, parallel increase in the blood and spleen, reaching a maximum at both sites by days 25-30. At the maximum, in the spleen the concentration of CFU-S was 10 times greater than that in the blood, and the total number of CFU-S was over 100 times greater than that of normal animals. During the same period, in the bone marrow the number of CFU-S decreased to one-half of normal. Nevertheless, the CFU-S from MPSV-infected animals differentiated normally in the spleens of irradiated, normal recipient mice (except for some hyperplasia of the erythroid component of spleen colonies). The CFU-C content of the bone marrow, spleen, and blood paralleled the CFU-S content of these organs: The CFU-S and CFU-C populations changed almost synchronously after MPSV infection. In the terminal stage of the MPSV-induced disease, a variable proportion of the CFU-C population acquired the ability to differentiate in the absence of added colony-stimulating factor.

Biological and biochemical characterization of a somatostatin-producing human carcinoma established by heterotransplantation.

A somatostatin-producing human carcinoma cell line was established by heterotransplantation into athymic nude mice. The original material, which was derived from a colon tumor of a patient who had previously had bilateral ovarian tumors contained 66 ng extractable somatostatin/g tissue. Somatostatin-producing cells could be identified by immunohistochemistry within the first tumor transplants. Although initially the somatostatin concentration was low (14 ng/g) a progressive increase was observed with each successive transplantation so that after 10 passages it reached a level of 127 ng/g tissue. Analysis of tumor extracts by gel filtration and high-performance liquid chromatography indicated that somatostatin-14 was the only molecular form produced by the original and by the transplanted tumor after multiple passages. This result demonstrates that the tumor has the ability to constitutively express the prosomatostatin gene and to process the primary translation product to somatostatin-14.

Differential gamma-interferon response of human colon carcinoma cells: inhibition of proliferation and modulation of immunogenicity as independent effects of gamma-interferon on tumor cell growth.

The effect of recombinant gamma-interferon (IFN-gamma) on established human colon carcinoma cell lines as well as fresh tumor cells from colon carcinoma patients has been investigated with respect to growth inhibition, enhancement of HLA expression, and modulation of immunogenicity. A direct antiproliferative activity of IFN-gamma was observed in five of seven cell lines tested, with a reduction of [3H]thymidine incorporation between 30 and 90%. Depending on the cell line, the IFN-gamma doses required for maximal inhibition varied between 20 and 2 X 10(4) units/ml. Independent of this effect, IFN-gamma enhanced the expression of HLA-A,B,C antigens in all cells investigated and induced expression of HLA-DR in three of seven carcinoma cell lines. Antigenic modulation of Class I and II major histocompatibility complex antigens was paralleled by an enhancement of the in vitro immunogenicity in three of four established carcinoma lines and in three of three cases, using cells derived from primary tumor cultures. Induction or enhancement of both proliferative and cytolytic T-cell responses was obtained in allogeneic and in autologous mixed-lymphocyte tumor cell cultures.

Hexadecylphosphocholine stimulates the colony-stimulating factor-dependent growth of hemopoietic progenitor cells.

The effect of the antitumorally active hexadecylphosphocholine (He-PC) on the colony-stimulating factor (CSF)-dependent growth of human hemopoietic progenitor cells was studied. At low concentrations He-PC stimulated the CSF-dependent progenitor cell colony growth of three patients suffering from chronic myeloid leukemia (CML) and of three of six patients without hematological disorders. The stimulating effect was up to eight times that of the control using granulocyte colony-stimulating factor (G-CSF) and twofold in the case of granulocyte-macrophage colony-stimulating factor (GM-CSF), whereas only slight effects were noted when interleukin 3 (IL-3) or the combination of the CSFs was used as an additive. The stimulatory effects observed are far below the He-PC concentrations that are usually required for the in vitro growth arrest of cancer cells. At higher concentrations He-PC displayed suppressive effects, most pronounced in the case of G-CSF-dependent colony growth. At the concentrations investigated, He-PC failed to show any changes in the composition and distribution of specific colonies. He-PC by itself had no mitogenic activity. This indicates that He-PC acts as a co-stimulator. In the cases of myeloproliferative diseases and in the case of a patient without known hematological disorder, removal of accessory cells did not abrogate the He-PC-enhanced colony growth by CSFs. Thus, the stimulatory effect of low-dose He-PC seems not to be mediated by accessory cells.

Detection of metastasis-associated differences for receptors of glycoconjugates (lectins) in histomorphologically unchanged xenotransplants from primary and metastatic lesions of human colon adenocarcinomas.

Clinically applicable markers for tumor progression may be uncovered by selective analysis of biochemical parameters, supposedly participating in this complex process. Owing to the importance of specific protein-carbohydrate interactions in diverse biological processes, the pattern of the receptor part in this glycobiochemical recognition system, the sugar receptors (lectins), conceivably reflects biological properties of tumor cells in glycobiochemical terms. Therefore, we established and characterized xenografts from surgically removed specimens of a human primary colon adenocarcinoma and its metastatic lesions to liver of the same patient and of a histomorphologically similar primary colon adenocarcinoma of another patient in nude mice. Xenotransplantation and subsequent glycobiochemical analysis of material from early passages with a standardized procedure had been preferred to cell culture in monolayer on account of maintenance of a higher degree of organized histotypic assembly. Despite histomorphological similarities, the sugar receptor profile revealed significant differences in tumor-tumor and tumor-metastasis comparison, especially for alpha- and beta-galactoside-binding proteins. Tumor-metastasis differences were substantiated by a second successfully xenotransplanted pair of specimens. Comprehensive expansion of these initial data may eventually lead to desirable functional correlations with the different biological properties of histomorphologically similar primary colon adenocarcinomas and of the metastatic phenotype and to a rational development of therapeutic modalities to restrict tumor growth and spread.

Increased peripheral stem cell pool in MDS: an indication of disease progression?

The colony-forming capacity of the peripheral blood stem/progenitor cells (PBSC) in different forms of myelodysplastic syndrome (MDS) was investigated. In most cases of refractory anemia (RA) the colony growth of PBSC was definitely reduced as compared to the controls. However, in RA with unfavorable chromosomal aberrations, in refractory anemia with ringed sideroblasts (RARS) and in advanced stages of MDS such as refractory anemia with excess blasts (RAEB) and refractory anemia in transformation (RAEB-t), the number of myeloid progenitor cells increased up to 100-fold. In chronic myelomonocytic leukemia (CMML), the increase was even more marked, up to 350-fold. Although the number of PBSC was strongly elevated, these cells were not able to restore hematopoiesis in vivo. In conclusion, the increase of circulating colony-forming cells (CFC) seems to be associated with disease progression, and thus, the evaluation of PBSC could be an important parameter in the diagnosis of MDS.

The effect of stem-cell factor, interleukin-3 and erythropoietin on in vitro erythropoiesis in myelodysplastic syndromes.

An inherent defect of erythroid differentiation at the colony-forming unit blast (CFU-blast) compartment and (or) an impaired response of early erythroid progenitors (BFU-E) to growth stimulation are both considered to contribute to anemia in myelodysplastic syndromes (MDS). With the intention of improving survival and growth of early erythroid progenitors we investigated the effect of stem-cell factor (SCF) and interleukin-3 (IL-3) alone and in combination with erythropoietin, on the in vitro erythropoiesis of 13 patients with MDS and of three normal controls. SCF and IL-3 alone did not promote erythroid colony growth in MDS, while 3 cases responded to erythropoietin alone. In each of these, BFU-E colony growth could be increased by SCF, which was also found in all normal bone marrows. Altogether 6 cases showed a significant enhancement of BFU-E colony numbers by the combination of SCF and erythropoietin as compared to erythropoietin alone (P = 0.036). Out of the 6 responding cases, 5 belonged to the FAB-classified subgroups refractory anemia (RA) and refractory anemia with ringed sideroblasts (RA/RS) (5/5), while 1 patient was classified as having refractory anemia with excess of blasts (RAEB) (1/4). No patient with refractory anemia with excess of blasts in transformation (RAEB-T) (0/4) responded. In spite of these positive effects, the absolute number of BFU-E colonies remained reduced in all MDS cases when compared to normal controls. IL-3 proved ineffective in increasing the response to erythropoietin in MDS although it increased erythropoietin-induced BFU-E formation in normal controls significantly. We conclude that the striking synergistic effect of SCF and erythropoietin on erythroid colony formation seen with normal bone marrow is conserved in most cases with RA and RA/RS. In RAEB and RAEB-T the intrinsic defect of the erythroid differentiation pathway cannot be overcome by SCF.

Effect of ether lipids on mouse granulocyte-macrophage progenitor cells.

In this study we determined the potential bone marrow toxicity of the ether lipid derivatives 1-0-octadecyl-2-0-methyl-rac-glycero-3-phosphocholine (OcMe-G-3-PC), 1-0-hexadecyl-propanediol-2-phosphocholine (He-Pr-2-PC), and hexadecylphosphocholine (He-PC). OcMe-G-3-PC inhibited the proliferation of mouse granulocyte-macrophage progenitor cells (GM-CFCs) at a dose of 1 micrograms/ml, whereas He-Pr-2-PC and He-PC started to inhibit the growth of hemopoietic precursors at 5 micrograms/ml. In contrast to this finding, NMRI mice given 10 mg/kg i.v. daily for 4 weeks and 20 or 30 mg/kg for 5 days showed no bone marrow toxicity. We conclude that the dose-dependent toxic effects observed in vitro are within the physiological tolerance in vivo.

Evidence for the involvement of protein-carbohydrate interaction in hematopoietic, multipotential colony-stimulating factor-dependent stem cell proliferation.

Immunologically important mediators have been shown to exhibit ability to specifically bind distinct carbohydrates. This type of protein-carbohydrate interaction is one mechanism how to explain involvement of glycochemical interactions in regulatory processes. Interference of certain saccharides with murine multipotential colony-stimulating factor (multi-CSF)-dependent colony formation from progenitor cells in semisolid agar raised evidence for similar potential involvement of protein-carbohydrate interactions. Affinity depletion of conditioned WEHI-3B-medium on resins, bearing saccharides that have been elucidated to be effective inhibitors (mannose and lactose), resulted in preparations with significantly reduced capability to sustain development and proliferation. Sequence comparison of multi-CSF to carbohydrate-binding proteins (lectins) with this specificity failed to uncover extended homologies in diagonal plots. But detailed sequence alignments revealed confined, high-scoring stretches of homology between various lectins and two types of CSF. These results prove the importance of protein-carbohydrate interactions in stem cell proliferation.

Stimulation of human hematopoietic progenitor cells by the alkylphosphocholines hexadecylphosphocholine and hexadecyl-N,N,N-trimethyl-hexanolamine.

Hexadecylphosphocholine (HePC) represents a new class of membrane-active antitumoral compounds, the alkylphosphocholines. In vivo studies of HePC showed an increase in the total white blood count (WBC) in the highest dosage group in DMBA-induced breast carcinoma in the rat. In phase II studies most of 70 patients treated orally with HePC likewise showed a significant increase in WBC and a rise in platelet count. The present investigation on human bone marrow progenitor cells from 42 patients shows a dose-dependent and selective co-stimulatory effect of HePC on the G-CSF-dependent growth of bone marrow progenitor cells in progenitor cells from 22 patients. Hexadecyl-N,N,N-trimethyl-hexanolamine(HePC6), which has no, or only marginal antitumoral activity but comparable physicochemical properties to HePC, also stimulates the G-CSF-dependent colony formation in a dose-dependent manner. The molecular mode of action of the stimulating effect of HePC on G-CSF-dependent colony formation is not entirely understood. An inhibitory effect of HePC and ether lipids on protein kinase C (PKC) has been described. However, there also is evidence that etherlipids can stimulate PKC, which plays a crucial role in proliferation and survival of hematopoietic cells, under more physiological conditions. Therefore, the most likely explanation for the stimulating effect of HePC on G-CSF-dependent colony formation might be interference with signal transduction pathways.

Characterization of membrane lectins in human colon carcinoma cells by flow cytofluorometry, drug targeting and affinity chromatography.

Flow cytofluorometry and drug targeting with labelled neoglycoproteins are used as tools to probe for membrane lectins in two human adenocarcinoma cell lines. Both cell lines express activities for galactosides, glucosides and fucosides. Affinity chromatography on gels with immobilized sugar leads to purification of an alpha-galactoside-binding protein at an apparent molecular weight of 64 kDa that also binds to lactose, maltose and fucose and exhibits Ca2+-requirement for binding, a beta-galactoside-binding protein without Ca2+-requirement at an apparent molecular weight of 14 kDa, and an alpha-glucosyl-binding protein without Ca2+-requirement at an apparent molecular weight of 34 kDa from both cell lines. The description of membrane lectins, documented here for the first human tumor cell lines, is an initial step towards a lectin-based improvement of the clinical management of human colon adenocarcinoma.

Xenografts from a human colon carcinoma and its metastases: establishment, characterization and differences in the pattern of carbohydrate-binding proteins.

Investigation of the pathogenesis of human colorectal carcinoma metastasis can be rendered experimentally possible by suitable human cell biological model systems. The purpose of these studies was to establish xenografts in nude mice from human colon carcinoma and from its metastasis in the same patient as an appropriate model. Surgically removed biopsy specimens from a colon adenocarcinoma (grade 3) and its local relapse two years later with metastases in the small intestine were established as xenotransplants and their growth characteristics examined. Both tissue types shared common characteristics with respect to marker expression (carcinoembryonic antigen, neuron-specific enolase, cytokeratin). The primary tumor showed remarkable development of necrotic effusion with cytotoxic activity that ceased after several passages. The profile of endogenous carbohydrate-binding proteins (lectins), the receptors for cellular glycoconjugates in a recognitive protein-carbohydrate interplay with potential relevance to metastases formation, revealed differences between these two human tumor samples of identical origin, especially with respect to beta-galactoside-specific receptors. This glycobiochemical analysis employed standardized procedures. Prolonged passaging was also shown to result in profile alterations, as was similarly noted in comparison to another species. These studies may encourage the application of systems of primary tumor and its metastases in the same patient in attempts to correlate the expression of cellular characteristics with the biological and clinical behavior of human colonic tumor cells.

[Large volume, isovolemic erythrocytapheresis in treatment of polycythemia vera. Effect of massive iron depletion of proliferation behavior of erythroid precursor cells (BFU-E)]. / Grossvolumige, isovolämische Erythrozytapherese in der Behandlung der Polycythaemia vera. Einfluss des massiven Eisenentzugs auf das Proliferationsverhalten erythroider Vorläuferzellen (BFU-E).

BACKGROUND: Isovolemic large volume erythrocyte-apheresis (EA) is a rapid, effective and well-tolerated treatment modality for red blood cell (RBC) depletion in patients with polycythaemia vera (PV). According to clinical observations its long lasting effect (median interval from EA to EA about 6 months) may, at least in part, be due to the associated loss of iron. METHODS: Therefore we investigated the influence of EA on the proliferative capacity of erythroid (BFU-E) and granulocyte-macrophage (GM-CFU) progenitor cells and on the erythropoietin-(EPO-)independent, spontaneous in vitro growth of BFU-E in particular. In six patients RBC and iron parameters as well as the proliferative capacity of hematopoietic progenitor cells were determined before and after EA. RESULTS: RBC parameters (in median) were before/after EA: RBC 7.64/5.93 x 10(6)/microliter; Hct 53/40%; Hb 15.5/12.0 g/dl and remained at reduced levels for several months; serum iron and ferritin levels decreased, while transferrin levels and transferrin receptor expression on peripheral mononuclear cells were enhanced. Serum EPO-levels were temporarily but only slightly increased. In all patients there was a significant inhibition of the growth of BFU-E detectable after EA while the GM-CFU were less affected. Within 3 to 6 weeks, the inhibition of endogenous BFU-E ranged from 53% to 100% and of EPO-dependent BFU-E from 31% to 74%. The inhibition of EA associated BFU-E growth could be reduced by in vitro addition of FeCl3. On the other hand, in vitro exposure of progenitor cells to an equivalent concentration of the iron chelator DFO (deferoxamine mesylate) resulted in a total suppression of progenitor cell growth. CONCLUSION: Our data suggest that the long lasting effect of EA is not only due to the high volume removal of RBC itself, but also to the growth inhibition of EPO-independent and -dependent BFU-E which is obviously mediated by the considerable loss of iron by EA.

Effect of microenvironment and cell-line type on carbohydrate-binding proteins of macrophage-like cells.

The pattern of sugar inhibition of rosette formation, a model for intercellular interaction between cultured cells and glutaraldehyde-fixed, trypsinated rabbit erythrocytes, served to infer the presence of carbohydrate-binding proteins. This profile from cell extracts for the two murine macrophage-like cell lines, P388D1 and J774A.1, was comparatively analyzed by affinity chromatography on supports with immobilized carbohydrates (lactose, L-fucose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and maltose) or with the immobilized mannose-rich yeast glycoprotein mannan or fetuin-derived glycopeptides containing sialic acid residues. After elution with specific sugar in the absence of Ca2+ ions, the proteins were separated by sodium dodecyl sulfate - polyacrylamide slab gel electrophoresis. The composition of carbohydrate-binding proteins of the two lines clearly exhibited quantitative and qualitative differences. Moreover, the pattern of P388D1 cells was also demonstrated to change significantly in response to alterations in the conditions of the physiological environment. These alterations were imposed by in vitro growth, by subsequent in vivo growth in nude mice, and by re-adaptation of cells to culture after in vivo passage. Collectively, our observations and other physiological and biochemical reports on macrophage lectins indicate that the presence of sugar receptors with different specificities may be an indicator of macrophage differentiation, being reversibly modulated to a considerable extent by external factors, e.g., microenvironment. Extensive but selective alterations in this respect could play an important role in the control of recognition and effector mechanisms within diverse functions of macrophage subpopulations.

Hexadecylphosphocholine induces interferon-gamma secretion and expression of GM-CSF mRNA in human mononuclear cells.

The effects of hexadecylphosphocholine (HePC) on secretion of interferon-gamma (IFN-gamma) and steady-state levels of IFN-gamma and GM-CSF mRNA were studied in human mononuclear cells. Cells from healthy donors were stimulated with either interleukin 2 (IL-2) alone, IL-2 plus phytohemagglutinin (PHA), or IL-2 plus HePC. In IL-2-treated cultures, the concentration of IFN-gamma was low. IFN-gamma and GM-CSF transcripts were not detectable by Northern blot analysis. In contrast, IL-2 plus HePC strongly increased the expression of the IFN-gamma and the GM-CSF genes and the secretion of IFN-gamma in most analyzed cultures. A similar effect could be detected with IL-2 plus PHA. The HePC-mediated enhancement of cytokine expression appeared later than the PHA-induced stimulation. These data indicate that HePC is able to enhance the immune response of IL-2-stimulated mononuclear cells resulting in GM-CSF and IFN-gamma gene expression and IFN-gamma secretion.

The growth capacity of hematopoietic progenitor cells in severe neutropenia induced by famotidine.

In four cases of severe neutropenia of unknown origin we found a strong inhibition of the growth of granulocyte-macrophage (GM) progenitor cells. The development of GM colonies in culture (GM-CFU-c) was more than 80% reduced in comparison to the control group. In particular, the interleukin 3-(IL-3) and granulocyte macrophage colony-stimulating factor-(GM-CSF) dependent growth was affected; a combination of growth factors (IL-3, GM-CSF, and G-CSF, the granulocyte colony-stimulating factor) resulted in a less reduced growth. The findings were primarily compatible with drug-induced bone marrow failure. Among the medications given to the patients, famotidine, an H2-receptor blocker, was discussed as an agent which possibly triggers off this process. After the withdrawal of famotidine, in three cases a continual increase of the growth of GM precursors was detected, reaching the normal level 7-17 days later. In one case, further investigations of the progenitor cells could not be carried out due to the death of the patient, but the rapid increase of neutrophils in the peripheral blood after withdrawal of famotidine pointed to the recovery of hematopoiesis. In vitro studies showed that famotidine, depending on the dose, inhibits the single growth factor-dependent colony growth (IL-3, GM-CSF, or G-CSF) of bone marrow progenitors from a concentration as low as 10 micrograms/ml. With the combination of all three growth factors only slight inhibitory effects were detectable (up to 150 micrograms/ml famotidine). These results indicate that famotidine, in common with other H2-receptor antagonists, can affect hematopoietic progenitor cells. However, the plasma concentration of famotidine normally used in ulcer therapy does not seem to influence the hematopoiesis. Apparently, the progenitor cells of only a few patients possess a higher sensitivity to the blockade of H2-receptors at this concentration of famotidine. This was demonstrated in one case (patient 3) 2 years after the patient had recovered from famotidine-induced neutropenia. The growth of peripheral myeloid, erythroid, and multilineage progenitor cells of this patient was remarkably reduced even at famotidine concentrations of 0.1-5.0 micron/ml whereas in the control group no inhibition was detected at these famotidine concentrations. Again, the IL-3-dependent colony formation was more affected than in the case of the combination of IL-3, GM-CSF, and G-CSF. After the removal of accessory cells the inhibitory effect of famotidine persisted, demonstrating that accessory cells do not play a major role in this process.

Hexadecylphosphocholine-mediated enhancement of T-cell responses to interleukin 2.

The effect of low-dose hexadecylphosphocholine (He-PC) on normal peripheral mononuclear cells (PMNC) was studied. Interferon-gamma (IFN-g) production, interleukin 2 (IL-2) receptor, and HLA-DR antigen expression were investigated, representing typical T-cell activation parameters. In PMNC cultures, He-PC dose-dependently enhanced the production of IFN-g, provided IL-2 had been added exogenously. Without IL-2 He-PC was ineffective. In some cultures, at a concentration of 8 micrograms/ml He-PC stimulated the secretion of IFN-g more than 20-fold compared to untreated controls. Although He-PC by itself lacked mitogenic activity, this compound also stimulated IFN-g production in the presence of suboptimal doses of phytohemagglutinin (PHA). Immunofluorescence studies demonstrated that He-PC also increased IL-2 receptor and HLA-DR antigen expression under these experimental conditions. Taken together, these results indicate that He-PC may possess immunomodulatory activity also in vivo, acting as a costimulator for the IL-2-mediated T-cell activation process.

Suppressed colony formation of peripheral blood lymphocytes in a patient with somatostatinoma.

The in vitro clonal growth of T lymphocytes was examined in a patient with somatostatinoma over a period of 8 months. After phytohemagglutinin stimulation colony-forming unit T lymphocytes could not be detected as compared to healthy controls and patients with metastatic colon tumors. The somatostatin produced by this tumor was identified as somatostatin-14. Synthetic somatostatin-14 inhibits significantly the colony formation and the tritiated thymidine incorporation of human peripheral T lymphocytes obtained from healthy subjects, suggesting immunoregulative properties of this neuroendocrine peptide.

Differential expression of endogenous sugar-binding proteins (lectins) in murine tumor model systems with metastatic capacity.

In order to investigate possible differences in sugar binding activities of strongly versus weakly metastatic tumors, sugar-binding molecules (endogenous lectins) of murine tumor cells differing in metastatic capacity were analyzed by affinity chromatography on supports with immobilized sugars or glycoproteins and compared. After elution with specific sugar in the absence of Ca2+-ions, the proteins were separated by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. In comparison to a weakly metastatic subline (Eb) spontaneous strongly metastatic variants (ESb) of a murine lymphoma contained additional sugar receptors for N-acetylglucosamine (Mr 30 kDa) and maltose (Mr 64 kDa, 62 kDa, 54 kDa and 32 kDa), and lacked one sugar receptor for myoinositol (Mr 85 kDa), N-acetylglucosamine (Mr 23 kDa) and maltose (Mr 22 kDa), respectively. The strongly metastatic variant ESb expressed the common beta-galactoside-specific lectin to a higher extent and receptors for myo-inositol, melibiose and mannan to a lower extent. In another model system derived from the murine mastocytoma cell line P 815 X 2A, biochemical analysis of the liver-metastasizing variant P 815 X 2B revealed additional characteristic N-acetylgalactosamine- and maltose-specific binding proteins. This variant had reduced amounts of receptors for beta-galactosides and fucose in comparison to the parental clone. In a third tumor system a similar qualitative difference was disclosed: a metastatic variant derived from spleen metastases displayed a sugar receptor profile with 5 additional beta-galactoside-binding proteins when compared to its parental clone 6-6#3 + F, which is a virally transformed fibroblast line. The results show that metastatic variants of 3 murine tumor models consisting of lymphomas, mastocytomas and sarcomas are characterized by qualitative and quantitative alterations in the profiles of sugar-binding proteins.

Carbohydrate-binding proteins of tumor lines with different growth properties. II. Changes in their pattern in clones of transformed rat fibroblasts of differing metastatic potential.

A tumor model system of clones of myeloproliferative sarcoma virus (MPV)-transformed rat fibroblasts (NRK) with different growth properties and metastatic potential was studied. The relationship between metastatic behavior and composition of carbohydrate-binding proteins (lectins) was analyzed by affinity chromatography. The metastatic variant differs qualitatively from its parental clone in the presence of galactoside-binding proteins at apparent molecular weight of 42 kDa. The alpha-glucosyl-binding proteins at apparent molecular weights of 67 kDa and 53 kDa and a galactoside-binding protein of apparent molecular weight of 34 kDa, however, are not detectable in the metastatic variant in comparison to its parental clone. In this respect the parental clone shows closer resemblance to the clone 5-8#1 with different growth properties and low metastatic potential than to its own metastatic variant. Furthermore, only the parental clone has a melibiose- and a mannan-binding protein of an apparent molecular weight of 64 kDa and 14 kDa, respectively. Rosette formation as model system for intercellular interaction reveals differences in the inhibition pattern with sugar between the two clones 5-8#1 and 5-20#20, whereas the metastatic variant 5-20#20 (s) exhibits drastically reduced capability to form rosettes. Initial experiments demonstrate the feasibility of drug targeting to transformed fibroblasts via carbohydrate-binding proteins.