Detection of the 170 kDa P-Glycoprotein in Neoplastic and Normal Tissues

A membrane purification procedure and an immunoblotting assay have been designed to allow screening of human solid tumors for overexpression of the GP170 glycoprotein without employing a disaggregation method to obtain cell suspensions. The electrophoresed membrane proteins were probed, after Western Blotting, with the C219 monoclonal antibody and iodinated Protein A. The labeling intensity of the bands on the autoradioimmunoblots were quantified by densitometry. To test for the presence of GP170, we used membranes from the UV 2237 fibrosarcoma line and its adriamycin-resistant variant ADMR, grown in vitro or as solid tumor in mice. Membranes of human normal and tumor tissues obtained from previously untreated patients were also tested. An immunoreaction was observed in the adriamycin-resistant UV 2237 lines grown in vitro or in vivo. Quantitatively, the binding of the resistant cell line grown in vitro was higher than that observed in cells grown in mice. Bands in the GP 170 region were observed in 4/7 normal and in 7/7 tumor colon tissues and in the normal medulla from 2 patients with cancer of the renal cortex. No reaction could be found in samples from normal tissue, primary tumor or nodal metastasis from 7 patients with breast cancer.

Interaction with hyperthermia of tetrachloroplatinum(II)(Nile blue)2 and tetrachloroplatinum(II)(neutral red)2 in EMT6 murine cells and the murine FSaIIC fibrosarcoma

Complexes of the tetrachoroplatinum(II) dianion with positively charged nuclear dyes were prepared in an effort to produce agents which gain ready access into the nucleus and become very cytotoxic at clinically relevant hyperthermia temperatures. Pt(Nile blue)2 and Pt(neutral red)2 are complexes of tetrachloroplatinum(II) with two closely related p-quinonediamine dyes. Pt(Nile blue)2 and Pt(neutral red)2 were only moderately cytotoxic to exponentially growing normally oxygenated or hypoxic EMT6 cells in vitro at pH 7.40 and 37 degrees C. At pH 7.40 and 42 degrees C and especially at 43 degrees C, however, Pt(Nile blue)2 became far more cytotoxic. At pH 6.45 Pt(Nile blue)2 became more toxic toward hypoxic cells (cell kill of 3.5 logs at 500 microM, 42 degrees C for 1 h). Pt(neutral red)2 became much more cytotoxic at pH 6.45 and 42 degrees C or 43 degrees C compared to pH 7.4, and the cell kill observed was similar in both euoxic and hypoxic cells (3 logs at pH 6.45, 43 degrees C with only 100 microM). Tumor cell survival studies in the FSaIIC murine fibrosarcoma demonstrated that both drugs killed in a dose-dependent log-linear manner. Hyperthermia treatment (43 degrees C, 30 min) immediately after either drug resulted in a dose modifying effect. The tumor growth delay produced by Pt(Nile blue)2 (100 mg/kg) was 4.6 days and by Pt(neutral red)2 (100 mg/kg) was 3.8 days. Both drugs were markedly improved by hyperthermia (tumor growth delay 1.4 days for hyperthermia; tumor growth delay 10.9 days for Pt(Nile blue)2 and 8.0 days for Pt(neutral red)2. Intracellular platinum levels were approximately 200 times higher after exposure of EMT6 cells to 25 microM of Pt(Nile blue)2 or Pt(neutral red)2 for 1 h at 37 degrees C than after exposure to the same concentration of cis-diamminedichloroplatinum(II). Treatment of cells with the drugs at 42 degrees C (1 h) resulted in no change in platinum levels with cis-diamminedichloroplatinum(II), but with Pt(Nile blue)2 and Pt(neutral red)2 an increase of 2- to 3-fold was found. Since previous work has shown that both of these complexes are active radiosensitizing agents, these new drugs seem quite well suited for further development as antitumor agents for use against solid tumors alone and in conjunction with hyperthermia and/or radiation therapy.

Purification and characterization of recombinant plasminogen activator inhibitor-1 from Escherichia coli

A recombinant form of plasminogen activator inhibitor-1 (rPAI-1) has been purified from lysates of pCE1200, a bacterial expression vector containing the full length PAI-1 gene, by utilizing sequential anion exchange and cation exchange chromatography on Q-Sepharose and S-Sepharose columns. Approximately 140 mg of rPAI-1, estimated at 98% purity on the basis of analytical high performance liquid chromatography, could be obtained from 200 g wet weight of cells. The purified protein exhibited a single Coomassie Blue-stainable band at the region of Mr = 42,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an NH2-terminal amino acid sequence consistent with the expected translation product of the pCE1200 PAI-1 insert. The rPAI-1 rapidly inhibited single- and two-chain tissue plasminogen activators, as well as urokinase, with apparent second order rate constants in the range of 2-5 x 10(7) M-1 s-1. A specific activity measurement of 250,000 units/mg was calculated for the rPAI-1 based on its ability to inhibit the enzymatic activity of a single-chain tissue plasminogen activator. Stability studies showed that the activity of the rPAI-1 was very stable when stored at temperatures of 25 degrees C or lower, but decayed within hours when stored at 37 degrees C. Sodium dodecyl sulfate treatment, which partially activates the latent form of natural PAI-1, inactivated rPAI-1. These results show that the purified rPAI-1 produced from pCE1200 displays many of the properties associated with the biologically active form of natural PAI-1.

Spectral editing of tumor 13C MRS in situ

The editing pulse sequence DEPT (D.T. Pegg, D.M. Doddrell, and M.R. Bendall, J. Chem. Phys. 77, 2745 (1982)) was modified using a scheme of various composite pulses and a 16-step phase cycling to obtain proton-decoupled natural-abundance 13C edited subspectra of solid tumors. A solenoidal probe including a Faraday shield and an orthogonal saddle decoupling coil was built for this purpose.

Glycosphingolipid expression on murine L1-fibrosarcoma cells: analysis of clonal in vivo and in vitro selected sublines with different lung colonisation potential

The patterns of acidic and neutral glycosphingolipids (GSLs) were examined in a syngeneic tumour system in Balb/c mice consisting of closely related cell lines with different colonisation potentials directed to the murine lungs (in vivo selected highly metastatic sublines of L1-fibrosarcoma cells and their WGA-resistant mutants with low metastatic potential). GSLs were analysed by high-performance thin-layer chromatography and structurally identified by fast atom bombardment mass spectrometry combined with compositional analyses and exo-glycosidase digestion. The results suggest that highly metastatic sublines L1-LM and L1-LM12 derived by in vivo selection from mouse fibrosarcoma cells (cell line L1) exhibit a drastic increase of polar ganglioside expression and a restriction to globo-series GSLs. Contrasting with this the low metastatic mutant cells (L1-LM13WGA) express a reduced portion of acidic GSLs and exhibit a shift to less polar ganglioside components. Total cellular and plasma membrane-integrated GSLs were demonstrated to exhibit largely identical patterns. Concomitant with a significant decrease in LacCer expression a substantial reduction of GM2 and a complete lack of GM3 expression can be assigned to the highly metastatic sublines of L1-cells. On the other hand, the more polar gangliosides GM1a and, to an even greater extent, GD1a (exceeding 70% of total gangliosides) accumulate on L1-LM and their clonal sublines. The shift to acidic GSLs of higher polarity is less pronounced on the low metastatic WGA-resistant mutant cells (L1-LM13WGA) showing a preponderance of GM1a. The portion of GD1a within the fractions of acidic GSLs does not correspond to the cellular activities of CMP-NeuAc/GM1 (alpha 2-3) sialyltransferase measured for high and low metastatic cell variants. Total sialic acid content of the various cell lines differs, but is not associated with the metastatic potential. Gangliosides on L1-cells exhibit a significant substitution of N-glycolyl for N-acetylneuraminic acid (13%) compared to their metastatic sublines and to mutant cells (less than 1%). A conversion of surface exposed GD1a to GM1a on membranes of metastatic cells by in situ treatment with Vibrio cholerae sialidase is associated with a significant reduction of tumour cell colonisation directed to the murine lungs.

Dexamethasone-induced plasminogen activator inhibitor: characterization, purification, and preparation of monoclonal antibodies

The effects of dexamethasone on protein synthesis were studied in human fibrosarcoma (HT-1080) cells. Dexamethasone induced a new protein of 46 kD which was rapidly secreted into the medium, while neither progesterone nor estradiol would induce the synthesis of this protein and only a small increase in its amount could be seen in the presence of testosterone. The 46 kD protein was partially purified by ammonium sulfate precipitation and gel filtration and mouse monoclonal antibodies to it were produced in mouse hybrid cells. Altogether 13 positive clones were found, of which six reacted only with native and seven reacted with the unreduced 46 kD protein in Western blotting. It was possible by using polyclonal antibodies to plasminogen activator inhibitor type I (PAI-1) and purified plasminogen activator inhibitor type I to confirm that the 46 kD protein purified and characterized here was PAI-1. In addition, the 46 kD protein clearly inhibited plasminogen activation, thus further confirming that protein isolated was an inhibitor of plasminogen activator. Since the induction of PAI-1 by dexamethasone was very extensive, it is possible that glucocorticoids regulate proteolysis and fibrinolysis in vivo by increasing the amount of the inhibitor of plasminogen activator and thus preventing the activation of plasminogen to plasmin. The reduction of activation of plasminogen to plasmin by glucocorticoid-induced inhibitor could be of great importance, e.g., in various blistering diseases, in metastases from malignant cells, and in the migration of inflammatory cells.

Immunohistochemical analysis of bone morphogenetic protein (BMP) in osteosarcoma

The monoclonal antibody against bovine bone morphogenetic protein (bBMP-McAb) was first used for demonstration of bone morphogenetic protein (BMP) in osteosarcoma. The avidin-biotin complex method (ABC) demonstrated that of the 18 osteosarcomas, 15 stained positive, while all 6 fibrosarcomas were negative. The results showed that BMP mainly exists in the tumor cell plasma and some tumor-like bone tissues. Using this staining method, we can not only differentiate osteosarcoma from fibrosarcoma and other non-bone-derived tumors, but also classify osteosarcoma according to the content and distribution of BMP and the patient's clinical situation, thus providing a scientific basis for clinical treatment.

An immunohistochemical study of dermatofibrosarcoma protuberans supports its fibroblastic character and contradicts neuroectodermal or histiocytic components

Paraffin-embedded material from 26 cases of dermatofibrosarcoma protuberans (DFSP) was investigated by the peroxidase-antiperoxidase technique. Antibodies to S-100 protein, Leu-7 antigen, and neuron-specific enolase (neural markers); to lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin (histiocytic markers); and to cytokeratin, desmin, vimentin, and factor VIII were used. The tumor cells reacted only for vimentin. In addition, 12 cases showed positive reactions with histiocytic markers (1-3% of the cells; in two cases, up to 10%). These results support a fibroblastic and contradict a neural or histiocytic histogenesis of DFSP.

[Flow cytometry for the determination of DNA in head and neck carcinomas]

The technique used for DNA determination in tumoral cells from carcinomas of head and neck is described. Results obtained are commented on as is too the future of this technique for the better understanding of the behavior of the tumor and consequently of its treatment.

The expression of intermediate filaments in canine mammary glands and their tumors

Monoclonal antibodies specific for different types of intermediate filaments (cytokeratin, vimentin, desmin and neurofilaments) were used to study the histogenesis of canine mammary glands and 57 canine mammary tumors by immunocytochemistry. The intra- and interlobular duct epithelium, acinar, and intralobular myoepithelial cells stained positively for cytokeratin. Peripheral ductal and acinar cells, as well as interstitial cells, stained positively for vimentin. A similar staining pattern was seen in adenomas, complex adenomas, benign mixed tumors, ductular carcinomas, and one myoepithelioma-like tumor. Additionally, cytokeratin positive cells were scattered interstitially in one single adenoma, most complex adenomas, some benign mixed tumors, complex carcinomas, and in the malignant mixed tumors. All stromal cells stained positively for vimentin. The fibrosarcomas were positive only for vimentin, while the following expressed both desmin and cytokeratin: epithelial-like cells in one adenoma, three complex adenomas, the myoepithelioma-like tumor, the single comedo carcinoma, two complex carcinomas, the single lobular carcinoma, one malignant mixed tumor, and three osteosarcomas. Epithelial-like cells in one adenoma, six complex adenomas, two benign mixed tumors, two complex carcinomas, the lobular carcinoma, and the malignant schwannoma stained for neurofilaments. Three tumors, one adenoma, one complex adenoma, and the lobular carcinoma expressed both desmin and neurofilaments in addition to cytokeratin and vimentin. The results show the expression of different types of intermediate filaments and indicate that there might be a stem cell origin in most of the canine mammary tumors.

The Mr 140,000 fibronectin receptor complex in normal and virus-transformed human fibroblasts and in fibrosarcoma cells: identical localization and function

We studied the function and localization of the fibronectin receptor complex in cultured normal and SV40-transformed human fibroblasts and in human fibrosarcoma cells by using monoclonal antibodies (MAbs) against the beta sub-unit of the receptor. Immunoprecipitation, fibronectin fragment affinity chromatography and immunoblotting results suggested that all the cells studied had similar amounts of the receptor. In normal fibroblasts MAbs additionally immunoprecipitated a smaller polypeptide, revealed as the precursor for the beta sub-unit and another polypeptide shown to be the alpha sub-unit of the VLA-I complex. The emergence of vinculin-positive focal adhesion sites and actin stress fibers was slower in the malignant cells than in normal fibroblasts when the cells were plated on non-coated glass-substrate in serum-free conditions and the fibronectin receptor complex did not become located to focal adhesions in any of the cells studied. Added substratum-bound but not soluble fibronectin mediated assembly of the fibronectin receptor complex to the focal adhesions in both normal and malignant cells. On fibronectin-coated growth substrate stress fibers also emerged as rapidly in the malignant cells as in normal fibroblasts. In all the cells the receptor complex, however, became largely dissociated from the focal adhesions within 48 hr. In cell adhesion conditions MAb against the alpha sub-unit of VLA-I complex revealed an even cell-surface labelling in normal fibroblasts and lack of labelling in malignant cells.

Immunohistochemical evaluation of Leu-7, myelin basic-protein, S100-protein, glial-fibrillary acidic-protein, and LN3 immunoreactivity in nerve sheath tumors and sarcomas

The collective expression of five antigens produced in immature or mature myelin-producing glia was evaluated in nerve sheath tumors and spindle cell sarcomas with histologic features of schwannomas. Myelin-associated glycoprotein (Leu-7), myelin basic-protein (MBP), S100-protein, and, in most cases, glial-fibrillary acidic-protein (GFAP) and HLA-DR/Ia (LN3) immunoreactivity were evaluated immunohistochemically using commercially available antibodies on 53 benign nerve sheath tumors and 12 sarcomas. Leu-7 immunoreactivity was detected by a monoclonal antibody in 12 of 16 schwannomas, 12 of 20 neurofibromas, and 17 of 17 traumatic neuromas. No Leu-7 positivity was seen in the sarcomas. Distinct heavy MBP immunoreactivity, assessed using polyclonal antibodies, was identified only in all 17 traumatic neuromas. Extensive S100-protein positivity was seen in 15 of 16 schwannomas, 17 of 20 neurofibromas, and 17 of 17 traumatic neuromas. Extensive LN3 immunoreactivity was seen in Schwann cells of 50% of the nerve sheath tumors analyzed; however, it was also present in associated interdigitating reticulum cells; GFAP immunoreactivity was not detected. These data suggest that Leu-7 is an important marker of Schwann cell neoplasms, although it is not superior to S100 protein. Moreover, combined immunohistochemical evaluation of potential Schwann cell markers including Leu-7, MBP, GFAP, and LN3 using commercially available antibodies offers no advantage over analysis of S100-protein immunoreactivity alone.

Spindle-cell and pleomorphic neoplasms of the skin. A clinicopathologic and immunohistochemical study of 30 cases, with emphasis on "atypical fibroxanthomas"

Atypical fibroxanthoma belongs to the family of spindle-cell and pleomorphic neoplasms of the skin. The lineage of differentiation of this tumor and the means whereby it can be diagnostically separated from other similar morphologic entities have been controversial. In order to address these issues, the authors studied 30 spindle-cell and/or pleomorphic cutaneous tumors, including atypical fibroxanthomas (AFXs), superficial malignant fibrous histiocytomas (MFHs), dermatofibrosarcoma protuberans (DFSPs), sarcomatoid squamous-cell carcinomas (SCCs), spindle-cell malignant melanomas (MMs), and leiomyosarcomas, (LMSs). These cases were analyzed using a panel of eight antibodies and the immunoperoxidase technique. AFXs were reactive for vimentin, alpha-1-antichymotrypsin (AACT), alpha-1-antitrypsin (AAT), and cathepsin-B (CB) but failed to display cytokeratin (CK), epithelial membrane antigen (EMA), S-100 protein, and desmin. MFHs and DFSPs exhibited immunophenotypic profiles that were nearly identical to that just described. In contrast, SCCs were typified by positivity for CK and EMA; MMs exhibited uniform reactivity for S-100 protein; and LMSs contained desmin in four of five cases. A surprising result was the expression of S-100 by LMSs. Also, all tumors displayed at least one of the three proteolytic enzymes assessed in this study (AAT, AACT, and CB), demonstrating the relative diagnostic nonspecificity of these determinants. It is concluded that AFXs are "fibrohistiocytic" neoplasms, with substantial morphologic and immunohistochemical similarity to MFHs. The immunohistochemical classification of spindle-cell and pleomorphic tumors of the skin necessitates the use of antibody panels to assess the presence of markers that are characteristic of each diagnostic group.

Nucleolar organiser regions in fibrous proliferations of childhood and infantile fibrosarcoma

A silver colloid technique to identify nucleolar organiser region associated protein (AgNOR) was applied to 16 fibrous proliferations of childhood and six low grade fibrosarcomas. The fibrous proliferations comprised five cases of infantile digital fibromatosis, seven of infantile desmoid type fibromatosis, and four of infantile myofibromatosis. The AgNORs were visualised as dots within the nuclei of the cells, and on the basis of their relative mean numbers of AgNORs fibrous proliferations of childhood could be easily differentiated from low grade infantile fibrosarcoma. The differences observed were significant (0.01 greater than p greater than 0.001). This technique, previously the province of the cytogeneticist, may be of use to the pathologist in differentiating infantile fibrous proliferations.

Flow cytometric DNA analysis of malignant fibrous histiocytoma and related fibrohistiocytic tumors

Fibrohistiocytic neoplasms with similar histologic characteristics may have vastly different biologic behaviors. We studied 23 fibrohistiocytic tumors to determine if cellular DNA content was correlated with clinical outcome. Archival paraffin blocks of 9 malignant fibrous histiocytomas (MFH), 3 dermatofibrosarcoma protuberans, 9 dermatofibromas, 1 juvenile xanthogranuloma, and 1 nodular fasciitis were processed, stained with propidium iodide, and analyzed by flow cytometry. Five of 9 (56%) MFH and 1 of 3 (33%) dermatofibrosarcoma protuberans were aneuploid. All 11 benign fibrohistiocytic tumors were diploid. Local recurrence occurred in 3 of 5 (60%) cases of aneuploid MFH, but in none with a diploid MFH tumor. No cases of dermatofibrosarcoma protuberans or benign tumors recurred. Aneuploidy was associated with decreased survival, as 2 of 5 patients with aneuploid MFH died within 1 year of diagnosis whereas all 4 patients with diploid MFH tumors are alive after an average follow-up of 4 years (range, 1 to 11). The diploid and aneuploid groups did not differ in clinical stage at the time of diagnosis. Our results indicate that retrospective DNA analysis can detect aneuploidy in both MFH as well as other fibrohistiocytic tumors, and that aneuploidy in MFH may place the patient at increased risk for local recurrence and mortality.

Cell-surface laminin-like molecules and alpha-D-galactopyranosyl end-groups of cloned strongly and weakly metastatic murine fibrosarcoma cells

Indications from previous work that cancer cell-surface laminin-like molecules and alpha-D-galactopyranosyl end-groups may contribute to spontaneous metastasis were further investigated. Both moieties are known to mediate cell attachment to various foreign surfaces. Five strongly metastatic and 5 weakly metastatic cell clones from a murine fibrosarcoma were examined for the occurrence of both cell-surface moieties by immunofluorescence flow cytometry and microscopy. None of these clones was rich in laminin-like molecules, which were least strongly expressed by the highly metastatic clones. The alpha-D-galactopyranosyl end-groups were strongly expressed by all strongly metastatic clones and by 2 weakly metastatic clones, but were only weakly expressed by the other weakly metastatic clones. These results indicate that the laminin-like cell-surface molecules are not necessary for spontaneous metastasis formation. However, the alpha-D-galactopyranosyl end-groups may be necessary, but are not sufficient for the cancer cells to form metastases. These carbohydrates are known to occur on the laminin-like molecules. The present results show that they must also exist on other cell-surface molecules.

Fibrosarcoma of the urinary bladder. Study of a case showing extensive chondroid differentiation

A case of primary fibrosarcoma of the urinary bladder showing extensive chondroid differentiation was studied by light microscopy and immunofluorescent microscopy using tissue-specific antibodies against intermediate filaments. The tumor cells were uniformly and positively labeled with vimentin antibodies and were negative for desmin and keratin, thus confirming the nonmuscle mesenchymal origin of the neoplasm. The value of intermediate filament typing in the differential diagnosis of spindle cell tumors of the urinary bladder is discussed, and a review of the literature on the subject is presented. It is postulated that the retained capacity for continued differentiation displayed by this tumor may account for the relatively better prognosis observed for this patient.

Characterization of tumor rejection antigen molecules of chemically induced murine colon tumor C-C26

The molecular nature of a tumor-specific transplantation antigen (TSTA) of a chemically induced BALB/c mouse colon tumor C-C26 was investigated. The antigen was noncytolytically extracted by 2.5% n-butanol treatment of the cells. Crude butanol extract from C-C26, but not from colon tumor C-C51 and fibrosarcoma Meth-A of BALB/c mice could provide protection against the challenged C-C26 tumor in the transplantation experiment. Crude butanol extract from another syngeneic colon tumor C-C36 also induced a cross-protection against the challenged C-C26 tumor. C-C26 crude butanol extract was characterized by biochemical procedures including the Sephadex G200 column, lens culinaris affinity column, and anion-exchange Mono Q fast protein liquid chromatography column, and by the enzyme digestion study of the antigens and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The data indicated that C-C26 TSTA was eluted into fractions containing molecules of approximately Mr 200,000 on Sephadex G200 column chromatography. This antigen was also found in unbound fractions on a lens culinaris affinity column. The antigen was further separated into the fraction that was eluted with 0.4 M NaCl in an ionic strength on Mono Q fast protein liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of this fraction showed the molecule with a molecular weight of 30,000. The enzyme digestion study indicated that the immunogenicity of the antigen was inactivated by papain but probably not by neuraminidase treatment. These data suggest that the immunogenic moiety of C-C26 TSTA molecules is located in the peptide portions rather than in sialic acid residues or carbohydrate portions. Furthermore, there are several similarities of the molecular characteristics between C-C26 TSTA and previously reported C-C36 TSTA, such as the amenability to n-butanol extraction. Lens culinaris lectin inaffinity, and ionic strength.

Plasminogen activator inhibitors from placenta and fibrosarcoma cells are antigenically different as evaluated with monoclonal and polyclonal antibodies

Plasminogen activator inhibitor (PAI) purified from human placenta was compared to PAI purified from conditioned cell culture fluid of the human fibrosarcoma cell line HT-1080. The two inhibitors had a similar mobility (Mr approximately 50,000) in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Purified placental inhibitor revealed 2 major and 1 minor Coomassie blue stainable bands, while the fibrosarcoma inhibitor appeared as one band. By immunoblotting analysis both monoclonal and polyclonal antibodies against each of the inhibitors showed reaction with the inhibitor against which they were raised, but not cross reaction with the other inhibitor. Similar results were obtained, when antibody binding was tested by ELISA with the inhibitors coated on the solid phase. HPLC fingerprint patterns of cyanogen bromide fragments of the two inhibitors were different. The inhibitory activity of the placental PAI was decreased by a factor of 3 after incubation with SDS, while that of the fibrosarcoma PAI was increased by a factor of 30. It is concluded that the two inhibitors show no detectable common antigenic determinants and most likely are products of different genes.

Immunohistochemical demonstration of desmin in canine smooth muscle tumors

Sections of formalin-fixed, paraffin-embedded canine leiomyomas, leiomyosarcomas, or fibrosarcomas were examined by immunohistochemical methods for the presence of desmin. Twenty-two leiomyomas and leiomyosarcomas were stained using the avidin-biotin complex technique, and 14 samples demonstrated positive staining for desmin. The eight negative results obtained may reflect differences in fixation or the affinity of the primary antibody for the tissues examined. Desmin was specific for myogenic tissues. Five canine fibrosarcomas examined immunohistochemically were all negative for desmin staining. The results indicate that desmin is a useful marker for immunohistochemical identification of canine leiomyomas and leiomyosarcomas.

Lectin histochemistry of malignant fibrohistiocytic tumors

The staining pattern by Ricinus communis agglutinin (RCA), a lectin used as a good marker for histiocytes, in 24 cases with malignant fibrous histiocytoma (MFH) was studied and compared with that of 12 cases of fibrosarcoma (FS). In 20 (83%) of 24 cases of MFH, varying degrees of RCA binding were observed, whereas only four (33%) of 12 cases of FS were positive. RCA-positive FS included three cases with infantile FS and one adult case with post-radiation FS. Eight adult patients with FS were entirely negative. This positivity rate of RCA binding in MFH was much higher than those of antisera against lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin previously reported. Seven MFH patients with focal aggregation of RCA-positive benign-appearing (reactive) histiocytes died earlier than the other patients with only scattered RCA-positive histiocytes; 5-year survival rates were 32% and 69%, respectively (p less than 0.05). These findings suggest that RCA reactivity can be used as a potential diagnostic and prognostic marker for MFH.

Non-polarizable collagen in dermatofibrosarcoma protuberans: a useful diagnostic aid

The stroma in dermatofibrosarcoma protuberans (DFSP) stains with trichrome, but is not polarizable (birefringent, doubly refractile). The usefulness of polarizing neoplastic stroma as a diagnostic aid in distinguishing DFSP from dermatofibroma and fibromatosis was evaluated. Forty cases of dermatofibroma of all types, 12 cases of dermal fibromatosis, and 15 cases of DFSP were examined. None of DFSPs contained polarizable collagen, whereas 11 of the 12 (92%) fibromatoses and 35 of the 40 (88%) dermatofibromas did. Of the 5 dermatofibromas that did not polarize, all were composed primarily of round to polyhedral histiocytic cells, including foam cells, frequently surrounding small obliterated capillaries. Although not pathognomonic, the presence of nonpolarizable collagen appears to be an additional histological marker useful in differentiating DFSP from dermatofibroma and fibromatosis.

Purification and characterization of heparin-binding endothelial cell growth factors

Thirteen endothelial cell growth factors have been purified to homogeneity by heparin affinity and reversed-phase high performance liquid chromatography, and their chromatographic and electrophoretic properties were compared. The amino acid compositions of 10 of these mitogens have also been determined. The results indicate that these heparin-binding growth factors (HBGFs) can be subdivided into two classes. Class 1 HBGFs are anionic mitogens of molecular weight 15,000-17,000 found in high levels in neural tissue and include acidic brain fibroblast growth factor and retina-derived growth factor. Class 2 HBGFs are cationic mitogens of molecular weight 18,000-20,000 found in a variety of normal tissues and are typified by pituitary fibroblast growth factor and cartilage-derived growth factor. Typical class 2 HBGFs have also been isolated from a rat chondrosarcoma, a human melanoma, and a human hepatoma, suggesting that tumors do not make a structurally distinct HBGF class. These results provide a sound basis for the evaluation of the HBGFs purified from a variety of tissues and species and for the delineation of their normal and pathological functions in vivo.

Interaction between Raf and Myc oncogenes in transformation in vivo and in vitro

3611 MSV, a raf-oncogene-transducing murine retrovirus, induces fibrosarcomas and erythroid hyperplasia in newborn mice after a latency of 4-8 wk. In contrast, new recombinant murine retroviruses carrying the myc oncogene (J-3, J-5 construct viruses) do not induce tumors before greater than 9 wk. A combination of both oncogenes in an infectious murine retrovirus (J-2) induces hematopoietic neoplasms in addition to less prominent fibrosarcomas and pancreatic adenocarcinoma 1-3 wk after inoculation. The hematologic neoplasms consist of immunoblastic lymphomas of T and B cell lineage and erythroblastosis. If animals were inoculated with a variant of the J-3 virus, which induces altered foci in cultures of NIH 3T3 cells, carcinoma developed in the pancreas with a 2-6 mo latency. In parallel to the synergistic action of both oncogenes on hematopoietic cells in vivo, we find that raf-oncogene-induced transformation of bone marrow cells in culture is enhanced by the addition of myc, which by itself does not transform these cells when grown in standard media. We conclude that concomitant expression of raf and myc oncogenes in hematopoietic and epithelial cells alters their respective transforming activities. The contribution of v-myc in this synergism was examined by use of a series of recombinant murine retroviruses capable of expressing the avian v-myc to study the effect of altered myc expression on hematopoietic/lymphoid cells. With either interleukin 3- or interleukin 2-dependent cell lines, introduction of the recombinant viruses abrogated the requirement for IL 3 or IL 2 for growth, and associated with this was the suppression of c-myc expression. The findings suggest that myc is a component in the signal transduction pathway for IL 3 and IL 2 and support an autoregulatory mechanism of c-myc expression. In contrast to v-myc, expression of v-raf in primary lymphoid/hematopoietic cells has an immortalizing function without abrogating the requirement for IL 3 for growth. This suggests that v-raf and v-myc affect different components of growth regulation, as, for example, commitment (v-myc) and cell cycle progression (v-raf).

DNA content of murine fibrosarcoma cell lines with varying metastatic potential

The DNA content of murine fibrosarcoma cell lines of various metastatic potential was the subject of the current investigation. The cell lines were derived from methylcholanthrene-induced tumors as described previously (J. Varani et al., J. Natl. Cancer Inst., 71: 1281-1287, 1983). Cells were maintained in vitro and used for DNA studies no more than 48 h after passage. DNA staining was accomplished using propidium iodide and flow cytometry was used to quantitate relative amounts of DNA. Trout and chicken erythrocytes and mouse thymocytes were used as internal DNA standards for each cell line. DNA indices were calculated as the ratio of the G0-G1 peak channel number of the tumor cells to the G0-G1 peak channel number of the thymocytes. Manual chromosome counts were also obtained from each cell line using Giemsa-stained preparations. All cell lines demonstrated a single aneuploid population. The two tumor lines with the highest metastatic potential were slightly hyperdiploid whereas three low metastatic lines were near tetraploid. A sixth line of moderate metastatic potential was also found to be near tetraploid. Chromosome counts and flow cytometric analyses were in close agreement indicating that DNA content was largely due to chromosome replication. These data suggest that, in this model, metastatic potential and DNA content are inversely related once diploidy is exceeded.

Enhanced granulopoiesis in mice transplanted with colony-stimulating factor-producing BMA1 tumor

Inoculation of BMA1 cells into BALB/c nude mice formed tumors (BMA1 tumor) that were transplantable into ddY mice, and induced marked granulopoiesis in vivo. Histological study revealed that the tumor was a fibrosarcoma, some parts of which were calcified, and consisted of hemopoietic foci surrounded by adipose tissue. This tumor was regarded as producing CSF in vivo as well as in vitro, since CSF activity was detected in sera of the tumor-bearing mice and tumor extract. Granulopoiesis and splenomegaly developed, associated with an increase of stem cells in the spleen. The number of CFUc and CFUs in the spleen increased to about 91 times and 21 times those of control mice, respectively, whereas the number of stem cells in the tibia did not change significantly. The number of peripheral leukocytes increased to 15 times that of normal mice and amounted to 78% of matured granulocytes. After tumor resection these hematological changes were reversed. The findings suggest that the granulopoiesis in BMA1 tumor-bearing mice may be induced by CSF produced by BMA1 tumor and that the spleen may be a direct target organ of the excessive amount of CSF.

Regulation of plasminogen activator activity in human fibroblastic cells by fibrosarcoma cell-derived factors

Low-molecular-weight protein factors (Mr 8,000 to 18,000) from serum-free conditioned medium of human fibrosarcoma (8387) cells reversibly enhanced the secretion of proteinase-inhibitory activity by cultured normal human skin fibroblasts. This inhibitory activity could be absorbed by immobilized plasminogen activator (PA) of urokinase type but not by heparin, and it was sensitive to treatment with sodium dodecyl sulfate. The secretion of a heparin-binding Mr 60,000 proteinase inhibitor, resembling protease nexin, was also detected. Early passages of adult skin fibroblasts do not contain or secrete PA. When cell types secreting this enzyme were tested, the fibrosarcoma-derived factors decreased the PA secretion detectable after sodium dodecyl sulfate treatment in all conditioned media of normal and malignant fibroblastic cells examined, including the 8387 cell line itself. However, no effects on the secretion of PA by normal or malignant cells of epithelioid origin or by melanoma cells were seen. A similar preparation from human epidermoid carcinoma (A431)-conditioned medium did not affect the PA activity or secretion of proteinase inhibitors from fibroblastic cells. The ability of sarcoma cells to modulate the production of PA inhibitors is a novel characteristic in the regulation of cellular proteolysis.

Inverse correlation between tumor incidence and tissue histamine levels in W/WV, WV/+, and +/+ mice

The influence of mast cells on tumor incidence and growth rate was studied in 2 grafted tumor models (fibrosarcoma MC-B6-1 and the Lewis lung carcinoma 3LL). Three kinds of WBB6F1 mice (a cross between WB/ReJ-W/+ and C57BL/6J-WV/+ mice) were used: W/WV (deeply mast cell depleted), WV/+ (partially mast cell depleted), and +/+ (normal mast cell number). The presumed resistance of F1 hybrids to tumor cells of parental origin was observed in 12 of 13 +/+ mice, but only in 11 of 22 WV/+ mice and in none of 39 W/WV mice. Tumor incidence and metastasis incidence were inversely correlated with tissue histamine levels and mast cell number. Growth rates of tumors were similar in W/WV and WV/+ mice, but the tumor growth rate was much slower in the only +/+ mouse in which the tumor grew. These results confirm the protective role of mast cells against tumors.

Sub-cellular distribution of copper and caeruloplasmin in chemically induced tumour tissue

Copper and caeruloplasmin concentrations were determined in the subcellular fraction of tumour tissue from 15 Strain A mice bearing an induced fibrosarcoma. It was observed that copper concentration was higher in the mitochondrial fraction of tumour tissue when compared to that of tissues of similar site from normal controls. However, the caeruloplasmin concentration was lower in the various fractions of tumour tissue when compared to that of normal control tissue.

NMR study of in vivo RIF-1 tumors. Analysis of perchloric acid extracts and identification of 1H, 31P and 13C resonances

Perchloric acid extracts of radiation-induced fibrosarcoma (RIF-1) tumors grown in mice have been analyzed by multinuclear NMR spectroscopy and by various chromatographic methods. This analysis has permitted the unambiguous assignment of the 31P resonances observed in vivo to specific phosphorus-containing metabolites. The region of the in vivo spectra generally assigned to sugar phosphates has been found in RIF-1 tumors to contain primarily phosphorylethanolamine and phosphorylcholine rather than glycolytic intermediates. Phosphocreatine was observed in extracts of these tumor cells grown in culture as well as in the in vivo spectra, indicating that at least some of the phosphocreatine observed in vivo arises from the tumor itself and not from normal tissues. In the 31P-NMR spectra of the perchloric acid extract, resonances originating from purine and pyrimidine nucleoside di- and triphosphate were resolved. HPLC analyses of the nucleotide pool indicate that adenine derivatives were the most abundant components, but other nucleotides were present in significant amounts. The 1H and 13C resonance assignments of the majority of metabolites present in RIF-1 extracts have also been made. Of particular importance is the ability to observe lactate, the levels of which may provide a noninvasive measure of glycolysis in these cells in both the in vitro states. In addition, the aminosulfonic acid, taurine, was found in high levels in the tumor extracts.

Distribution of laminin, fibronectin, and interstitial collagen type III in soft tissue tumours

The distributions of laminin, fibronectin, and interstitial collagen type III have been investigated in a series of 60 soft tissue tumours by immunochemistry. Positive laminin staining was seen in sites predicted by the distribution of ultrastructurally visible basal lamina. Pericellular laminin was present in all benign tumours of Schwann cell and smooth muscle origin examined, in the two malignant Schwannomas examined, and in six of 13 leiomyosarcomas. It was also evident around nests of cells in an alveolar soft part sarcoma and around malignant endothelial cells in an angiosarcoma. In fibroblastic and fibrohistiocytic tumours it was found only in blood vessel walls. The results of laminin staining led to revision of the original histopathological diagnosis in seven of the 60 cases studied. Fibronectin was abundant in the stroma of most neoplasms, both benign and malignant. It was also found in a distribution parallel to that of laminin. In some tumours this was clearly distinguishable from the distribution of interstitial collagen. Intracellular fibronectin was shown consistently only in mast cell granules. Its demonstration in synovial cells, fibroblasts, and histiocytes was more variable. Interstitial collagen type II had the most irregular distribution of the three proteins. It was as plentiful in tumours of smooth muscle origin as in tumours of fibroblastic origin, but was scanty in fibrous histiocytomas. Its distribution appeared similar to that of laminin and fibronectin in leiomyomas, but differed from these two proteins in Schwann cell tumours and other neoplasms. In one leiomyosarcoma fibronectin, laminin, and type III collagen appeared to be lost concomitantly from tumour cell peripheries.

Expression of cell surface P-glycoprotein by an adriamycin-resistant murine fibrosarcoma

Analysis of the cell membrane of Adriamycin (doxorubicin)-resistant UV-2237 ADMR murine fibrosarcoma cells revealed a 170,000-dalton component that is not found in the drug-sensitive parent or revertant cells. Immunoblot (Western blot) analysis showed that this component is similar to the 170,000-dalton P-glycoprotein found on the surface of Chinese hamster ovary cells that exhibit multidrug resistance. Thus, multidrug resistance and P-glycoprotein expression apparently can occur in a wide variety of cells, including the metastatic murine solid tumor cell line described here.

Immunomodulating activities associated with the cytosol fraction of a 3-methylcholanthrene-induced rat fibrosarcoma

Cytosol fraction(s) from McFiFi2(s) fibrosarcoma cells (Fcc), isolated from either cultured cells or solid tumors induced in F344 rats, produced a dose-related inhibition of lymphoproliferative responses to several mitogens, whatever the lymphoid organ or the animal species used as the source of lymphocytes. Only stimulated human lymphocytes were not Fcc inhibited; instead, Fcc was a potent stimulator of their spontaneous proliferation. Fcc cytostatic activity was not effective in various cycling cell lines and was restricted to mitogen-stimulated lymphocytes. Fcc, a primary tumor product, did not induce suppressive cells and was unable to prevent mitogen cell surface binding. However, expression of its modulating effect was accelerated by the simultaneous presence of the mitogen. Moreover, Fcc produced its suppression by interrupting lymphocyte activation at some point within the G0-G1-phase transition. Molecular sieving showed that Fcc contains at least two factors with suppressive (mol wt, approximately 3,000) and stimulatory (mol wt, greater than 5,000) activities, respectively.

A new platelet aggregating material (PAM) in an experimentally induced rat fibrosarcoma

The present work concerns our studies to search for factor(s) which may influence the hemostatic process in or around metastasis of tumours. We studied the platelet aggregating property of a methyl cholanthrene induced experimental tumour. Platelet aggregating material was found to be different from the known aggregating agents like thrombin, ADP, collagen, thromboxane A2 and trypsin. It depends on a critical level of calcium for its action. PAM is a high molecular weight substance which contains sialic acid. It is trypsin and plasmin insensitive. The activity of this substance is not being destroyed by phospholipase-C. Metabolic study indicates that PAM acts by mitochondrial energy metabolic pathway of the platelets.

Macrophage colony-stimulating factor and granulocyte colony-stimulating factor separated from fibrosarcoma tissue in mice

Large increases of granulocytes and monocytes were found in the blood of mice bearing fibrosarcoma. Extraction of the tumor tissue with isotonic saline yielded a colony-stimulating factor (CSF). Further extraction of the saline-insoluble materials with 0.1% sodium dodecyl sulfate afforded another pool of CSF. Incubation of the tumor cells in vitro resulted in the accumulation of CSF activity in the culture medium. The CSF from these sources produced both granulocyte colonies and macrophage colonies in murine bone marrow cell culture. Subsequently, the activity producing granulocyte colonies was separated from that producing macrophage colonies by isoelectrofocusing and repeated gel-filtration chromatography. It was also shown that anti-L cell CSF antiserum neutralized the macrophage CSF activity but not the granulocyte CSF activity. These results show that the granulocytosis-inducing tumor produces two types of CSF.

Responses of bone marrow gamma-glutamyltranspeptidase and alkaline phosphatase in vitro to tumor-elaborated granulocytopoietic factors

Evidence has been obtained for the humoral mediation of the recently noted tumor-induced rise of the host bone marrow gamma-glutamyltranspeptidase (gamma GT) and alkaline phosphatase (AP) content in vivo: normal rat bone marrow suspensions, if incubated for 18 hr to 3 days with serum from mammary carcinoma hosts, show 2- to 8-fold elevations (per cell) of the same 2 enzymes. The active substance(s) is in the acid-stable, HCI-ethanol-soluble polypeptide fraction of the mammary carcinoma extract, and of the hosts' blood serum. The larger the size of the neoplasm, and the faster its growth rate, the greater the effect of the host serum on the gamma GT and AP of the normal bone marrow cells. In host rats in vivo, this response is followed by increases in the number (as well as the gamma GT and AP content) of circulating granulocytes. Therefore, a positive response on the part of these enzymes in the bone marrow suspension was also sought, and found, upon incubation with preparations which enhance granulocyte colony formation in agar cultures (i.e., colony-stimulating factor and serum from endotoxin-treated rats). The results indicate: (a) that the increase in gamma GT and AP is a necessary prelude to stimulation of granulocyte multiplication by appropriate growth factors; and (b) that measurement of these enzymes in the short-term liquid culture offers a biochemical test for such factors elaborated by cancers or in nonneoplastic conditions.

Identification of a laminin-like substance on the surface of high-malignant murine fibrosarcoma cells

High- and low-malignant murine fibrosarcoma cells were stained with anti-laminin antibodies using immunoperoxidase techniques and examined by electron microscopy. With the high-malignant cells, specific staining was observed along the cell surface. Use of normal rabbit serum in place of the rabbit anti-laminin or pretreatment of the anti-laminin with soluble laminin completely eliminated this staining. No immunoperoxidase staining was observed with the low-malignant cells. In additional studies, membrane fractions were prepared from the high- and low-malignant cells and used to immunize rabbits. The animals immunized with the membrane fractions from the high-malignant cells produced antibodies that reacted by enzyme-linked immunosorbent assay (ELISA) with murine laminin obtained from the EHS sarcoma. The animals immunized with membrane fractions from the low-malignant cells did not. These studies provide strong evidence that the high-malignant cells (but not the low) express on their cell surface a substance that is immunologically cross-reactive with laminin. In addition, the high-malignant cells (but not the low) secreted a material into the cell culture fluid that could be specifically immunoprecipitated with antilaminin antibodies. The immunoprecipitated material co-migrated with purified laminin when examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis under reducing conditions. The existence of this substance associated with the surface of the high-malignant cells and its absence from that of the low-malignant cells may explain the previously noted difference between these cells in their ability to attach to type IV collagen. This difference may also contribute to the dissimilarity between these cells in their metastatic potential.

Isolation and characterization of DNA-binding proteins of Yoshida ascites tumour cells

DNA-binding proteins from the cytosol and nuclei of Yoshida ascites sarcoma cells were isolated by affinity chromatography on native and denatured DNA-cellulose columns. The proteins that were retained in the columns were eluted by increasing concentrations of NaCl and analysed by electrophoresis in polyacrylamide gels. Two proteins with approximate molecular weights (MW) of 38 000 (38K) and 34 000 (34K) D showed high affinity for denatured DNA and eluted in large quantities from denatured DNA-cellulose columns. In contrast, only small amounts of 38 000 and 34 000 D proteins were found to be associated with native DNA and the native DNA-associated 38K and 34K proteins showed higher rate of phosphorylation than the corresponding denatured DNA-binding proteins. The 38 000 and 34 000 D DNA-binding proteins were present both in nuclei and cytoplasm. These two proteins together comprised over 70% of the total DNA-binding proteins present in the 0.4 M NaCl eluate of the cytoplasmic extracts. DNA-binding proteins of MW 38 000 and 34 000 D were also present in a methylcholanthrene-induced fibrosarcoma, although in smaller amounts.

Glycosphingolipids in clonal variants of rat fibrosarcoma cells with different transplantability

Neutral glycolipids and gangliosides of four clonal variants of rat fibrosarcoma AS-653 cells with different transplantability were analyzed. A highly malignant clone A had a much lower quantity of GM3 ganglioside and a much higher quantity of lactosylceramide as compared to clones Z and G, which showed low transplantability and less malignancy, and a variant clone P, which showed tumorigenicity only in ascites form. A similar correlation was found with the quantity of an unidentified slow-migrating neutral glycolipid in various clones. This glycolipid was present in trace amount in the original highly malignant clone A, increased moderately in clones G and Z, and increased greatly in clone P, which showed no subcutaneous transplantability. The results of these studies suggest that a blockage of synthesis of GM3 ganglioside and a long chain neutral glycolipid occurred with enhanced malignancy, and an enhanced synthesis of GM3 ganglioside and the long chain neutral glycolipid is associated with a decrease in transplantability.

Nuclear magnetic resonance imaging of a fibrosarcoma tumor implanted in the rat

Fibrosarcoma tumor cells were implanted in the hind legs of 25 rats and studied from the first to the sixth week postimplantation. Nuclear magnetic resonance imaging detected all tumors and did not yield any false-positives in five control rats. The T1 relaxation values of tumors overlapped those of muscle, and the T2 values overlapped those of fat, but the combination of the two values allowed discrimination of each of the three tissues with no overlap. The difference in relaxation time between tumor and muscle could be accounted for on the basis of water content, which was approximately 14% higher in the tumors. This study confirms data from previous studies suggesting that nuclear magnetic resonance imaging is a highly sensitive modality, but that T1 and T2 values are not specific for individual pathologic conditions.

Isolation of a cell surface receptor protein for laminin from murine fibrosarcoma cells

We used affinity chromatography to isolate a specific laminin-binding protein from murine fibrosarcoma cells. These cells bind exogenous laminin to their surface with high affinity (Kd = 2 X 10(-9)M for laminin) with approximately 5 X 10(4) sites per cell. Laminin affinity chromatography of [35S]methionine-labeled cell extracts produced two distinct proteins. One was identified as Type IV (basement membrane) collagen based on its migration pattern on SDS gels and bacterial collagenase sensitivity. The other protein, which migrates as a single band or closely spaced doublet on reduced SDS gels, has a reduced molecular weight of 69,000. Using a nitrocellulose filter disk assay, we found that the latter protein specifically bound 125I-laminin with the same high affinity (Kd = 2 X 10(-9)M for laminin) as did intact fibrosarcoma cells. By iodinating intact cells, we demonstrated that this laminin-binding protein is on the cell surface. We conclude that this protein with reduced molecular weight of 69,000 is a subunit or component of a larger cell surface receptor protein for laminin in this fibrosarcoma model. This laminin receptor may mediate the interaction of the cell with its extracellular matrix.

Differential expression of a lamininlike substance by high- and low-metastatic tumor cells

High-metastatic murine fibrosarcoma cells readily attached to Type IV (basement membrane) collagen, whereas low-metastatic cells isolated from the same tumor did not. The addition of laminin--a glycoprotein that facilitates the adherence of epithelial cells to their basement membranes--enhanced the attachment of the low-metastatic cells, but not the high-metastatic cells. Using anti-laminin antibodies and a laminin-binding lectin as probes, the authors were able to identify by immunofluorescence a moiety associated with the high-metastatic cells, but not the low-metastatic cells, which cross-reacted with murine laminin purified from the EHS sarcoma. When extracts from the high-metastatic cells were separated by affinity chromatography, with the laminin-binding lectin as the affinity substrate, a substance was isolated that had an apparent molecular weight of 56,000 daltons. The affinity-purified material reacted strongly with anti-laminin antibodies by enzyme-linked immunosorbent assay.

Selective increased tissue histamine levels in tumour-bearing rodents

Histamine levels increased in the fundus of mice bearing a primary 3-methylcholanthrene-induced fibrosarcoma, and in the ventral skin, skeletal muscle and rumen of rats bearing a D.M.B.A. induced mammary adenocarcinoma; they did not increase in the tissues of mice bearing a McC3-1 fibrosarcoma (38th passage) or a Lewis lung carcinoma before the appearance of metastasis, but an increase in histamine levels was observed in dorsal skin, ventral skin and fundus, after the appearance of metastasis.

Feline sarcoma virus-specific transformation-related proteins and protein kinase activity in tumor cells

Polyproteins (gag-fes) encoded by the Synder-Theilen (ST) and the Gardner-Arnstein (GA) strains of feline sarcoma virus (FeSV) were previously shown to be associated with mink or rat cells that were nonproductively transformed in vitro. In the present study we demonstrated that the same gag-fes proteins were found in cat cells transformed in vitro. Of greater importance, these transformation-related proteins were also in cells taken from fresh biopsies of FeSV-induced tumors. Cells from fibrosarcomas induced with ST-FeSV had gag-fes proteins that were characteristic of this strain. Fibrosarcomas and melanomas were induced with GA-FeSV and both types of tumors contained the protein that is characteristic of cells transformed in vitro with this virus. Expression of these proteins in cultured tumor cells appeared to be independent of the passage level. Based on two-dimensional tryptic peptide analysis, the gag-fes proteins of cat tumor cells appeared to be indistinguishable from those found in cells transformed in vitro. The polyproteins of the cat tumor cells have a closely associated protein kinase activity, as demonstrated in the in vitro assay, and phosphorylated tyrosine residues. Gag-fes proteins of either the ST or GA class were not present in cell cultures initiated from five spontaneous cat tumors.

Distribution of the transferrin receptor in normal human fibroblasts and fibrosarcoma cells

Transferrin is required for proliferation of most cells in culture. This effect is presumably mediated by the binding of transferrin to its receptor, a surface glycoprotein which is preferentially expressed by actively growing cells. Here we show that normal human fibroblasts cultured in serum, and other media containing transferrin express transferrin receptors in a distinctly non-random way; punctate foci of the receptor were seen only at the leading lamellae of the cells, whereas cells grown without serum, or in transferrin-depleted serum showed a random distribution of the receptor. In contrast, malignant fibrosarcoma cells showed the receptor uniformly throughout the cell surface in all media tested, including those containing transferrin. The data suggest that the ligand causes a directional lateral movement of the receptor in normal but not in malignant cells. Application of the receptor antibody caused a rapid internalization of the receptor in both cell types.

Monophasic synovial sarcoma of spindle-cell type. Epithelial differentiation as revealed by ultrastructural features, content of prekeratin and binding of peanut agglutinin

Monophasic synovial sarcomas of spindle-cell type and fibrosarcomas were studied by electron and immunofluorescence microscopy for their intermediate filament expression and the binding of peanut agglutinin (PNA). In monophasic synovial sarcomas of spindle-cell type (two cases), frequent cell-to-cell junctions, irregular cytoplasmic processes, and occasional cytoplasmic, tonofilament-like bundles of intermediate filaments were seen by electron microscopy. These features were absent from fibrosarcomas. Immunohistologically, the monophasic synovial sarcomas showed arrays of prekeratin-positive cells in the midst of the vimentin-positive spindle cells. By double fluorescence microscopy, the prekeratin-positive cells also bound PNA, like the epithelial-like cells of the classical biphasic synovial sarcoma. In contrast to monophasic synovial sarcomas, prekeratin-positive cells and arrays of PNA-binding cells, were not seen by immunofluorescence microscopy in fibrosarcomas (seven cases). Thus the prekeratin-content, the binding of PNA lectin, and certain ultrastructural features suggesting early epithelial differentiation, help to distinguish monophasic synovial sarcomas of spindle-cell type from other spindle cell sarcomas.

Purification of immunoprotective tumor antigens by preparative isotachophoresis

Tumor-specific transplantation antigens (TSTA) were purified from 3 M KCl and butanol extracts of C3H/HeJ 3-methylcholanthrene-induced fibrosarcomas by preparative isotachophoresis (pITP). Fractions from pITP which reacted with antisera to TSTA preparations in an enzyme-linked immunospecific assay were tested in vivo for induction of resistance to the growth of transplanted tumor cells. Isotachophoresis of crude 3 M KCl extracts yielded TSTA that was immunogenic at doses between 17 and 124 micrograms. Isotachophoresis of TSTA partially purified from crude 3 M KCl or butanol extracts by preparative isoelectric focusing (pIEF) of 3 M KCl and butanol extracts yielded TSTA that was immunogenic over a two-fold log dose range. As little as 10 ng purified TSTA reduced tumor growth by 50%. Tumor growth reduction was specific, and immunized animals survived longer than non-immunized controls. A purification of 10,000-fold over crude 3 M KCl extracts and 2,500-fold over crude butanol extracts was obtained. These results suggest that TSTA from murine tumor cells is preparatively purified by following extraction with pIEF and then pITP.