Pulmonary artery intimal sarcoma mimicking pulmonary thromboembolism: A case report

RATIONALE

Pulmonary artery intimal sarcoma is a rare tumor with exceptionally high mortality and easily misdiagnosed as pulmonary thromboembolism pulmonary thromboembolism (PTE) due to the nonspecific clinical presentation and symptom. Misdiagnosis or untimely diagnosis makes the disease progress to an advanced stage and eventually leads to a poor prognosis.

PATIENT CONCERNS

A 37-year-old Chinese female presented with chest tightness and dyspnea for 3 months. Echocardiography and chest computed tomography revealed an intraluminal obstruction of the pulmonary arteries. Tests of serum tumor makers showed slight elevation for carbohydrate antigen-125, and α-fetoprotein. PTE was suspected according to the radiological and laboratory findings.

DIAGNOSIS

Microscopic findings of the presumed thrombus showed prominent myxoid and edematous background with atypical spindled cells and curvilinear vascularity. Immunohistochemical staining demonstrated that the atypical spindled cells were positive for vimentin but negative for CK, S100, SMA, desmin, CD68, STAT6, CD34, β-catenin, ALK-p80, p53, and MDM2. According to the radiological and pathological findings, the diagnosis of fibrosarcoma of pulmonary artery was made.

INTERVENTIONS

The patient underwent surgical resection and the mass was excised as completely as possible.

OUTCOME

Follow-up information showed no evidence of recurrence or metastasis after 3 months postresection.

LESSONS

Because of the low incidence rate, nonspecific clinical symptoms, and radiological findings, primary fibrosarcoma of the pulmonary artery is commonly misdiagnosed as PTE. Pathological examination is necessary to confirm the diagnosis.

Angiogenic factors FGF2 and PDGF-BB synergistically promote murine tumor neovascularization and metastasis

Tumors produce multiple growth factors, but little is known about the interplay between various angiogenic factors in promoting tumor angiogenesis, growth, and metastasis. Here we show that 2 angiogenic factors frequently upregulated in tumors, PDGF-BB and FGF2, synergistically promote tumor angiogenesis and pulmonary metastasis. Simultaneous overexpression of PDGF-BB and FGF2 in murine fibrosarcomas led to the formation of high-density primitive vascular plexuses, which were poorly coated with pericytes and VSMCs. Surprisingly, overexpression of PDGF-BB alone in tumor cells resulted in dissociation of VSMCs from tumor vessels and decreased recruitment of pericytes. In the absence of FGF2, capillary ECs lacked response to PDGF-BB. However, FGF2 triggers PDGFR-alpha and -beta expression at the transcriptional level in ECs, which acquire hyperresponsiveness to PDGF-BB. Similarly, PDGF-BB-treated VSMCs become responsive to FGF2 stimulation via upregulation of FGF receptor 1 (FGFR1) promoter activity. These findings demonstrate that PDGF-BB and FGF2 reciprocally increase their EC and mural cell responses, leading to disorganized neovascularization and metastasis. Our data suggest that intervention of this non-VEGF reciprocal interaction loop for the tumor vasculature could be an important therapeutic target for the treatment of cancer and metastasis.

A phase I-II preoperative biomarker trial of fenretinide in ascitic ovarian cancer

PURPOSE

To evaluate study feasibility, toxicity, drug concentrations, and activity of escalating doses of the synthetic retinoid fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] in ovarian cancer by measuring serum CA125 and cytomorphometric biomarkers in cancer cells collected from ascitic fluid before and after treatment.

METHODS

Twenty-two naive patients with ascitic ovarian cancer were treated with escalating doses of 4-HPR at 0, 400, 600, and 800 mg/d for 1 to 4 weeks before surgery. Changes in the proportion of proliferating cells expressed by Ki67 and computer-assisted cytomorphometric variables (nuclear area, DNA index, and chromatin texture) were determined in ascitic cells. Drug levels were measured by high-performance liquid chromatography.

RESULTS

Doses up to 800 mg/d were well tolerated, and no adverse reactions occurred. There was no effect of 4-HPR on changes in serum CA125, Ki67 expression, which were assessed in 75% of subjects, and cytomorphometric variables, which were assessed in 80% of subjects. Plasma retinol levels were significantly lower in affected women than healthy donors. 4-HPR plasma concentrations increased slightly with increasing doses and attained a 1.4 micromol/L concentration with 800 mg/d. Drug levels in malignant ascitic cells and tumor tissue were higher than in plasma but were 50 and 5 times lower, respectively, than in carcinoma cells treated in vitro with 1 micromol/L 4-HPR.

CONCLUSIONS

Cell biomarkers can be measured in ascitic cells to assess drug activity. Under our experimental conditions, 4-HPR did not show activity in advanced ovarian cancer cells. However, clinical evidence supports further investigation of fenretinide for ovarian cancer prevention.

[Systemic inflammation and experimental cancer in a murine model]

The link between cancer and inflammation in an organ or tissue has firmly been established on the basis that cancer tends to occur at sites of chronic inflammation and that local inflammatory processes can accelerate the growth of preexisting tumors in both animals and human beings. In contrast, the relationship between cancer and systemic inflammation has been less studied. In this work, we demonstrated that the growth of the murine fibrosarcoma MC-C, was accompanied by manifestations of systemic inflammation, as demonstrated by an increase in both the number of circulating polymorphonuclear neutrophils (PMN) and the serum concentration of the proinflammatory cytokines interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) and the acute phase proteins C reactive (CRP) and serum A amyloid (SAA). Two temporally separate peaks of systemic inflammation were detected during tumor development. The first was displayed during the first week after tumor inoculation. The second peak began around day 14 and its intensity was proportional to tumor size. In mice bearing a large MC-C tumor, a high number of circulating PMN and myeloid precursors were evident. Most of these cells exhibited activation evidenced by an increased reactive oxygen species generation and high expression of the Gr1+/Mac1+ markers. Inoculation of thioglycolate -which generates a transient systemic inflammation-accelerated the growth of MC-C tumor and reciprocally, inhibition of such systemic inflammation by using indomethacin, prevented that enhancing effect. This suggests that the systemic inflammation that the tumor generates on its own, could be part of its growth strategy.

Spatial heterogeneity and oxygen dependence of glucose consumption in R3230Ac and fibrosarcomas of the Fischer 344 rat

To examine the oxygen-dependence of glucose consumption in solid tumors, we monitored gradients of glucose, lactate, and hypoxia in R3230Ac and FSA tumors growing in Fischer 344 rats. Bioluminescence imaging, detection of Hoechst 33342, and immunostaining of the hypoxia marker EF5 [2-8-N-(2,2,3,3,3-pentafluoropropyl)acetamide] were done in serial tumor slices. Glucose and lactate levels were also determined in liver and blood. Cells were further tested for glucose consumption and lactate production in vitro. In both tumor types, EF5 staining indicated similar maximum levels of hypoxia; the most intense staining occurred in perinecrotic regions. Glucose concentrations were highest in liver, declined from blood to tumor edge, further into vital tumor regions, and were lowest close to necrosis. Glucose was significantly lower in FSA than in R3230Ac tumors. Glucose concentrations in R3230Ac tumors were consistently higher in nonhypoxic than in hypoxic areas, with maximum values equal to systemic blood levels. Glucose in FSA tumors was close to zero, regardless of the presence or absence of hypoxia. Lactate did not differ significantly between the tumor types. FSA cells in culture showed a trend towards higher aerobic glucose consumption versus R3230Ac. Both cell lines increased their lactate production to similar levels under hypoxia. We conclude that both R3230Ac and FSA tumors retain the Pasteur effect, i.e., hypoxia triggers increased glycolysis. However, our results imply that increased aerobic glucose utilization leads to low glucose levels in FSA and a situation where supply limits uptake. This explains the repeatedly observed correlation between tumor blood flow and 18F-deoxyglucose uptake.

Coagulation facilitates tumor cell spreading in the pulmonary vasculature during early metastatic colony formation

Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation might play a role in the metastasis, we used three-dimensional visualization of direct infusion of fluorescence labeled antibody to observe the interaction of tumor cells with platelets and fibrinogen in isolated lung preparations. Tumor cells arrested in the pulmonary vasculature were associated with a clot composed of both platelets and fibrin(ogen). Initially, the cells attached to the pulmonary vessels were rounded. Over the next 2 to 6 hours, they spread on the vessel surface. The associated clot was lysed coincident with tumor cell spreading. To assess the importance of clot formation, we inhibited coagulation with hirudin, a potent inhibitor of thrombin. The number of tumor cells initially arrested in the lung of hirudin-treated mice was essentially the same as in control mice. However, tumor cell spreading and subsequent retention of the tumor cells in the lung was markedly inhibited in the anticoagulated mice. These associations of the tumor cells with platelets were independent of tumor cell expression of P-selectin ligands. This work identifies tumor cell spreading onto the vascular surface as an important component of the metastatic cascade and implicates coagulation in this process.

Treatment-induced changes in tumor oxygenation predict photodynamic therapy outcome

Photodynamic therapy (PDT) requires oxygen to cause tumor damage, yet therapy itself can deplete or enhance tumor oxygenation. In the present work we measured the PDT-induced change in tumor oxygenation and explored its utility for predicting long-term response to treatment. The tissue hemoglobin oxygen saturation (SO(2)) of murine tumors was noninvasively measured by broadband diffuse reflectance spectroscopy. In initial validation studies, the oxyhemoglobin dissociation curve for mouse blood was accurately recreated based on measurements during deoxygenation of a tissue phantom of mouse erythrocytes. In vivo studies exhibited excellent correlation between carbogen-induced changes in SO(2) and pO(2) of radiation-induced fibrosarcoma tumors measured by reflectance spectroscopy and the Eppendorf pO(2) histograph, respectively. In PDT studies radiation-induced fibrosarcoma tumor SO(2) was measured immediately before and after Photofrin-PDT (135 J/cm(2), 38 mW/cm(2)). Animals were subsequently followed for tumor growth to a volume of 400 mm(3) (time-to-400 mm(3)) or the presence of tumor cure (no tumor growth at 90 days after treatment). In animals that recurred, the PDT-induced change in tumor SO(2), i.e., relative-SO(2) (SO(2) after PDT/SO(2) before PDT) was positively correlated with treatment durability (time-to-400 mm(3)). The predictive value of relative-SO(2) was confirmed in a second group of animals with enhanced pre-PDT oxygenation due to carbogen breathing. Furthermore, when all of the animals were considered (those that recurred and those that were cured) a highly significant association was found between increasing relative-SO(2) and increasing probability of survival, i.e., absence of recurrence. As independent variables, the SO(2) after PDT, the pre-PDT tumor volume, and light penetration depth all failed to predict response. As an independent variable, the SO(2) before PDT demonstrated a weak negative association with treatment durability; this association was driven by a correlation between decreasing pre-PDT SO(2) and increasing relative-SO(2). These data suggest that monitoring of PDT-induced changes in tumor oxygenation may be a valuable prognostic indicator.

Hyperforin Inhibits Cancer Invasion and Metastasis

Hyperforin (Hyp), the major lipophilic constituent of St. John's wort, was assayed as a stable dicyclohexylammonium salt (Hyp-DCHA) for cytotoxicity and inhibition of matrix proteinases, tumor invasion, and metastasis. Hyp-DCHA triggered apoptosis-associated cytotoxic effect in both murine (C-26, B16-LU8, and TRAMP-C1) and human (HT-1080 and SK-N-BE) tumor cells; its effect varied, with B16-LU8, HT-1080, and C-26 the most sensitive (IC50 = 5 to 8 micromol/L). At these concentrations, a marked and progressive decline of growth was observed in HT-1080 cells, whereas untransformed endothelial cells were only marginally affected. Hyp-DCHA inhibited in a dose-dependent and noncompetitive manner various proteinases instrumental to extracellular matrix degradation; the activity of leukocyte elastase was inhibited the most (IC50 = 3 micromol/L), followed by cathepsin G and urokinase-type plasminogen activator, whereas that of the matrix metalloproteinases (MMPs) 2 and 9 showed an IC50 > 100 micromol/L. Nevertheless, inhibition of extracellular signal-regulated kinase 1/2 constitutive activity and reduction of MMP-2 and MMP-9 secretion was triggered by 0.5 micromol/L Hyp-DCHA to various degrees in different cell lines, the most in C-26. Inhibition of C-26 and HT-1080 cell chemoinvasion (80 and 54%, respectively) through reconstituted basement membrane was observed at these doses. Finally, in mice that received i.v. injections of C-26 or B16-LU8 cells, daily i.p. administration of Hyp-DCHA-without reaching tumor-cytotoxic blood levels-remarkably reduced inflammatory infiltration, neovascularization, lung weight (-48%), and size of experimental metastases with C-26 (-38%) and number of lung metastases with B16-LU8 (-22%), with preservation of apparently healthy and active behavior. These observations qualify Hyp-DCHA as an interesting lead compound to prevent and contrast cancer spread and metastatic growth.

Preliminary study of plasma vascular endothelial growth factor (VEGF) during low- and high-dose radiation therapy of dogs with spontaneous tumors

High plasma vascular endothelial growth factor (VEGF) concentrations are associated with radiation resistance and poor prognosis. After an exposure to ionizing radiation in cell culture an early phase and a late phase of increased VEGF have been documented. The activation was dependent on the radiation dose. Therefore, the purpose of this study was to measure baseline plasma VEGF and changes in VEGF over the course of fractionated radiation therapy in dogs with spontaneous tumors. Dogs with tumors had a significantly higher pretreatment plasma VEGF than did dogs without tumors. Immediately after irradiation no increased plasma VEGF was observed. Over the course of radiation therapy there was an increased plasma VEGF in dogs treated with low doses per fraction/high total dose, whereas plasma VEGF remained stable in dogs irradiated with high doses per fraction/low total dose. The regulatory mechanisms are very complex, and therefore the value of plasma VEGF measurements as an indirect marker of angiogenesis induced by radiotherapy is limited.

Dose-Dependent Effects of Dietary - and -Tocopherols on Genetic Instability in Mouse Mutatect Tumors

Vitamin E in foodstuffs is a mixture of tocopherols. In mouse Mutatect tumors, a model designed to detect DNA mutations, the hypoxanthine phosphoribosyltransferase (Hprt) gene mutation frequency is associated with the number of tumor-infiltrating neutrophils and both are markedly decreased in mice fed high levels of alpha-tocopherol. Dietary alpha-tocopherol is also associated with a decrease in neutrophil-associated loss of an interleukin 8 (IL-8)-expressing transgene in this tumor model. We examined Hprt gene mutation frequency (expressed as the number of 6-thioguanine-resistant colonies per 10(5) clonable tumor cells), IL-8 transgene loss, and myeloperoxidase activity (an indirect measure of neutrophil number) in tumors from Mutatect mice fed diets supplemented with various concentrations of D-alpha-tocopherol acetate and/or D-gamma-tocopherol acetate or neither tocopherol for 4 weeks. Hprt gene mutation frequency and myeloperoxidase activity were statistically significantly lower in tumor cells from mice fed alpha-tocopherol at 50 or 100 mg/kg body weight per day than in tumor cells from mice fed 0 mg/kg body weight per day alpha-tocopherol (P<.001 for each comparison). IL-8 transgene loss occurred in 28 of 28 tumors (100%; 95% confidence interval [CI] = 86% to 100%) from mice fed alpha-tocopherol at 50 mg or less/kg body weight per day and seven of 18 tumors (39%; 95% CI = 24% to 54%) from mice fed 100 mg/kg body weight per day (P<.001, Fisher's exact test, referent groups [pooled] 0, 25, and 50 mg/kg). gamma-Tocopherol had no detectable effect on any of the three endpoints. Thus, dietary alpha-tocopherol decreases two forms of genetic instability in a dose-dependent manner in this experimental tumor model.

Plasma vascular endothelial growth factor (VEGF) measured in seventy dogs with spontaneously occurring tumours

BACKGROUND

Vascular endothelial growth factor (VEGF) acts specifically on endothelial cells mediating tumour neovascularisation and initiating tumour growth and metastasis. In humans, high VEGF levels are correlated with poorer prognosis but in dogs minimal information on plasma VEGF is available. Therefore, we analysed plasma VEGF in a variety of spontaneous canine tumours.

MATERIALS AND METHODS

Plasma from seventy dogs with various spontaneous tumours was taken prior to radiation therapy. A human VEGF ELISA was used for analysis.

RESULTS

Mean plasma VEGF was 7.2+/-7.8 pg/ml. Mean plasma VEGF level varied among different tumour types with the highest level in oral melanomas (12.4 pg/ml). In patients with sarcomas of soft tissue or bone origin, plasma VEGF levels increased significantly with decreasing haemoglobin concentration (p =0.013).

CONCLUSION

Canine plasma VEGF levels depend on tumour histology, with higher levels found in more aggressive tumours. The negative correlation between plasma VEGF and haemoglobin (hb) is most probably due to tissue hypoxia seen in anaemic animals.

Determination of vascular-endothelial growth factor levels in serum from tumor-bearing BALB/c mice treated with photodynamic therapy

MATERIAL/METHODS

We implanted a malignant tumour, BFS1 fibrosarcoma, into BALB/c mice and then treated them using a new photosensitizer, hydroxygallium (III) phthalocyanine tetrasulfonic acid tetrasodium salt, BON-6. The administration of this compound was followed by light irradiation using a halogen lamp at 680 nm. VEGF concentrations were measured in sera from the mice and compared to the time of tumor growth.

RESULTS

BON-6 was found to be effective in PDT. This feature was accompanied by low levels of VEGF after BON-6+PDT, and also prolongation of the time of survival of treated animals. The mice which received BON-6+PDT survived 83.8 days (SD 10.23). The mean survival time in control groups did not exceed 35 days. Additionally, measurement of tumor size showed total regression in single cases after BON-6+PDT.

CONCLUSIONS

PDT, by decreasing VEGF serum levels, may influence the capability of tumor tissue to form new vessels.

Tumor-host interactions accompanying the growth of the G:5:113 fibrosarcoma in the mouse: possibilities for a new therapeutic approach?

The experiments were aimed at describing in detail some interactions between a solid tumor growing from subcutaneously transplanted G:5:113 fibrosarcoma cells in vivo and its mouse host. The tumor was found to elevate significantly the number of granulocytes in the peripheral blood of the host after having achieved the volume of about 1 cm3 (day 40 after transplantation). Blood plasma from fibrosarcoma-bearing mice stimulated proliferation of progenitor cells for granulocytes and macrophages (GM-CFC) in vitro and suppressed growth of G:5:113 cell population in culture. Interestingly, both effects were observable as early as week 1 when the tumor was still macroscopically invisible and unpalpable. Conditioned medium from cultures of G:5:113 fibrosarcoma cells stimulated proliferation of GM-CFC in vitro. These findings might represent a starting point for studies aimed at designing new therapeutic approaches for the treatment of fibrosarcoma.

Immunomic analysis of human sarcoma

The screening of cDNA expression libraries from human tumors with serum antibody (SEREX) has proven to be a powerful method for identifying the repertoire of tumor antigens recognized by the immune system of cancer patients, referred to as the cancer immunome. In this regard, cancer/testis (CT) antigens are of particular interest because of their immunogenicity and restricted expression patterns. Synoivial sarcomas are striking with regard to CT antigen expression, with >80% of specimens homogeneously expressing NY-ESO-1 and MAGE-A3. In the present study, 54 sarcoma patients were tested for serum antibodies to NY-ESO-1, SSX2, MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, CT7, and CT10. Two patients had detectable antibodies to CT antigens, and this seroreactivity was restricted to NY-ESO-1. Thus, although highly expressed in sarcoma, CT antigens do not induce frequent humoral immune responses in sarcoma patients. Sera from these two patients were used to immunoscreen cDNA libraries from two synovial sarcoma cell lines and normal testis, resulting in the identification of 113 distinct antigens. Thirty-nine antigens were previously identified by SEREX analysis of other tumor types, and 2339 antigens (59%) had a serological profile that was not restricted to cancer patients, indicating that only a proportion of SEREX-defined antigens are cancer-related. A novel CT antigen, NY-SAR-35, mapping to chromosome Xq28 was identified among the cancer-related antigens, and encodes a putative extracellular protein. In addition to testis-restricted expression, NY-SAR-35 mRNA was expressed in sarcoma, melanoma, esophageal cancer, lung cancer and breast cancer. NY-SAR-35 is therefore a potential target for cancer vaccines and monoclonal antibody-based immunotherapies.

Laminin gamma2-chain fragment in the circulation: a prognostic indicator of epithelial tumor invasion

Laminin (LN) 5, the major component of epithelial-derived extracellular matrix (ECM), plays a major role in cell adhesion and motility. Previous reports stated that proteolytic processing of the NH(2)-terminal region of the gamma2 chain enhances cell motility on LN5, indicating that the degraded gamma2 chain NH(2)-terminal region would be shed from the ECM. However, soluble LN gamma2 NH(2)-terminal fragment (G2F) have not been detected in biological fluids. Here, we developed a double-monoclonal electrochemiluminescence immunoassay for human G2F and detected its presence in the normal human circulation (mean +/- SD: 39.2 +/- 10.3 ng/ml; n = 10). We also measured serum levels of G2F in nude mice orthotopically transplanted with three different human pancreatic carcinoma cell lines: MIApaca-II (secreting no LN5), HPAC (secreting the alpha3beta3gamma2 heterotrimer of LN5), or KP-1 (secreting the monomeric gamma2 chain of LN5). Serum levels of G2F drastically increased in the nude mice transplanted with HPAC (mean +/- SD: 351 +/- 33 ng/ml, 5 weeks after transplantation), the most invasive tumor cells to generate extensive peritoneal dissemination in vivo. A moderate increase in serum levels of G2F was also observed in mice transplanted with KP-1 (87.9 +/- 82 ng/ml, 5 weeks after transplantation), but no antigen was detected in the sera of MIApaca-II-transplanted mice. Therefore, circulating G2F was demonstrated to be a sensitive marker for LN5 production of primary pancreatic carcinomas, even if it was produced only as a monomeric gamma2 chain. In 11 established human pancreatic tumor cell lines (6 of LN5-producing cells and 5 of nonproducing cells), LN5-secreting cells have significantly higher levels of cell surface expression of beta4 integrin than nonsecreting cells. Thus, LN5 secretion is accompanied by cell surface expression of alpha6beta4 integrin, participating in hemidesmosome reorganization to form invading edges of malignant epithelial carcinomas. These data reveal that the level of circulating G2F is a new, prognostic, tumor-characterizing marker for estimating the invasiveness and malignancy of epithelial carcinomas in cancer patients.

Determination of basic fibroblast growth factor levels in serum of tumor-bearing BALB/c mice treated with photodynamic therapy

In the present study we have checked whether photodynamic therapy (PDT) may influence concentration of basic Fibroblast Growth Factor (bFGF) in in vivo conditions. We have implanted malignant tumor, i.e. BFS1 fibrosarcoma into BALB/c mice and have them treated using well established photosensitizer, hematoporphyrin derivative and new compound, hydroxygallium (III) phthalocyanine tetrasulfonic acid tetrasodium salt, BON-6. The administration of those compounds was followed by light irradiation using a halogen lamp at proper wavelengths. Our results indicate that in vivo photodynamic therapy may cause a significant decrease in bFGF concentration and this phenomenon is accompanied by prolongation of survival of treated animals.

Stat1 negatively regulates angiogenesis, tumorigenicity and metastasis of tumor cells

Stat1 is deficient or inactive in many types of human tumors whereas some tumors have activated Stat1. Whether Stat1 affects tumor growth and metastasis is unclear. In the present study, we used Stat1 knockout tumor cells to determine (1) whether Stat1 can regulate angiogenesis, growth, and metastasis of tumor cells; and (2) whether Stat1 is required for the inhibitory effect of IFN-beta on the expression of angiogenic factor bFGF. Highly tumorigenic and metastatic RAD-105 tumor cells derived from a fibrosarcoma of a Stat1 knockout mouse were reconstituted with a Stat1 expression vector. The reconstitution of Stat1 suppressed the tumorigenicity and metastasis of RAD-105 cells in nude mice which correlated with a decreased microvessel density and decreased expression of proangiogenic molecules bFGF, MMP-2, and MMP-9 in vivo. Moreover, noncytotoxic concentrations of IFN-beta significantly inhibited the in vitro expression of bFGF in the Stat1-reconstituted cells but not in the Stat1-deficient cells, which was consistent with decreased bFGF expression of Stat1-reconstituted tumors in vivo. Therefore, Stat1 is essential for IFN-mediated inhibition of bFGF production, suggesting that tumor-intrinsic Stat1 is an important mediator for antiangiogenic signals, such as IFN. Collectively, these data demonstrate that Stat1 expressed by tumor cells is a negative regulator of tumor angiogenesis and, hence, tumor growth and metastasis.

Identification of a tumor-associated contact-dependent activity which reversibly downregulates cytolytic function of CD8+ T cells

Tumors elicit an immune response in hosts and yet, paradoxically, often grow progressively with fatal consequences. This phenomenon has been attributed to the possible expression by tumor cells of immunomodulatory factors that overcome the anti-tumor effector functions of both specific and non-specific immune cells. This study reports on the ability of the methylcholanthrene-induced fibrosarcoma, Meth A, as well as other tumors of varied histological origins to downregulate the lytic activity of CD8+ T cells. The suppressive activity is contact-dependent and reversible. As tumor-bearing hosts are rarely immunosuppressed systemically, these findings may explain how local events within the tumor bed subvert the specific anti-tumor immune response.

Phosphoglycerate kinase acts in tumour angiogenesis as a disulphide reductase

Disulphide bonds in secreted proteins are considered to be inert because of the oxidizing nature of the extracellular milieu. An exception to this rule is a reductase secreted by tumour cells that reduces disulphide bonds in the serine proteinase plasmin. Reduction of plasmin initiates proteolytic cleavage in the kringle 5 domain and release of the tumour blood vessel inhibitor angiostatin. New blood vessel formation or angiogenesis is critical for tumour expansion and metastasis. Here we show that the plasmin reductase isolated from conditioned medium of fibrosarcoma cells is the glycolytic enzyme phosphoglycerate kinase. Recombinant phosphoglycerate kinase had the same specific activity as the fibrosarcoma-derived protein. Plasma of mice bearing fibrosarcoma tumours contained several-fold more phosphoglycerate kinase, as compared with mice without tumours. Administration of phosphoglycerate kinase to tumour-bearing mice caused an increase in plasma levels of angiostatin, and a decrease in tumour vascularity and rate of tumour growth. Our findings indicate that phosphoglycerate kinase not only functions in glycolysis but is secreted by tumour cells and participates in the angiogenic process as a disulphide reductase.

Two different types of concomitant resistance induced by murine tumors: morphological aspects and intrinsic mechanisms

Concomitant resistance (CR) is the phenomenon according to which a tumor-bearing host inhibits the growth of a secondary implant of the same tumor at a distant site. Confirming and extending previous results of our laboratory, histological studies have revealed that two temporally separate peaks of CR can be detected throughout tumor evolution. The first peak induced by immunogenic small tumors, in euthymic but not in nude mice, is associated with extensive necrosis of the secondary tumor implant and a profuse infiltration of polymorphonuclear granulocytes and mononuclear cells resulting in its final destruction; these features correspond to a typical immunological rejection. The second peak of CR induced by both immunogenic and non-immunogenic large tumors, in euthymic as well as in nude mice, is characterized by a dormant tumor stage with scarce or null mononuclear infiltration, associated with a significant reduction of tumor mitotic index and of the number of PCNA+ cells along with an increase in apoptosis and an arrest in S phase. In previous reports we suggested that a 1000 D serum fraction from mice bearing large tumors could be responsible for the induction of this dormant tumor stage. In this study tumor cells incubated in vitro with that serum factor mimicked the inhibition and cellular alterations observed in vivo in the secondary tumor inhibited by the second peak of CR. Moreover, the passive transfer of this factor by the intra-peritoneal (i.p.) route induced an in vivo inhibition of an i.p. tumor reproducing the image characteristic of the second peak of CR. This represents a direct proof that this serum factor can restrain tumor growth in vivo and that it is, most probably, the effector of the second peak of CR.

Blood perfusion of subcutaneous tumours in mice following the application of low-level direct electric current

Electrotherapy with low-level direct electric current has been proved to be an effective local treatment of solid tumours. In the presented study an attempt was made to evaluate the effect of a single treatment with electrotherapy on blood perfusion of solid subcutaneous fibrosarcoma Sa-1 tumours in A/J mice. The tissue-staining method with Patent blue-violet dye, the rubidium extraction technique, and the noninvasive near-infrared spectroscopy method were used for this purpose. Results of all methods indicate that perfusion and subsequently oxygenation of tumours were reduced due to application of electrotherapy.

Suppression of solid tumor growth by a monoclonal antibody against tumor vasculature in rats: involvement of intravascular thrombosis and fibrinogenesis

We have reported that immunization of rat tumor-derived endothelial cells (TEC) isolated from KMT-17 solid tumors results in the generation of several monoclonal antibodies (MAbs). TES-23, one of these MAbs, recognizes a naturally occurring 80-kDa antigen expressed on endothelial cells of tumor blood vessels. To determine whether such MAbs can suppress solid tumor growth in vivo by impairment of endothelial cells in tumors following direct binding, we tested the biodistribution of (125)I-labeled TES-23 in rats bearing KMT-17 solid tumors. We also examined the effect of treatment using unconjugated TES-23 on tumor growth and histo-pathological changes in tumor tissues. Biodistribution studies showed localization of TES-23 into tumor tissues 60 min after intravenous injection. TES-23 suppressed significantly the growth of KMT-17 solid tumors following administration for 5 days. Histo-pathological examination showed that TES-23 caused degeneration, apoptosis and/or necrosis and denudation of endothelial cells in viable tumor areas following local aggregation and adhesion of lymphocytes, with subsequent intravascular thrombus formation by platelets and fibrin. Our results indicate that TES-23, which recognizes TEC, can target endothelial cells of solid tumor vasculature directly, resulting in growth suppression in vivo by reduction of blood flow due to intravascular thrombosis. Our results also suggest that targeting tumor vasculature is a potentially attractive approach for the treatment of solid tumors.

Biochemical evaluation of antitumor effect of muthu marunthu (a herbal formulation) on experimental fibrosarcoma in rats

Natural products from plants are rich sources used for treating a number of diseases. Many of the pharmacological principles of the currently used anticancer agents have been initially isolated from plants. Most of the herbal drugs are a mixture of a number of plant ingredients. Their cumulative effect increases the efficacy of the drug in curing the diseases. Muthu Marunthu is a herbal formulation comprising of eight various plant ingredients, and has been claimed to possess antitumor effect. Therefore, attention has been focused on studying the various plant ingredients in the drug as a whole for its antitumor effects. It was observed that the growth rate in rats was normal and there was no change in blood parameters such as glucose, urea, proteins, cholesterol and also in the activities of pathophysiological enzymes such as lactate dehydrogenase (LDH), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), alkaline and acid phosphatase after Muthu Marunthu administration. The tumor weight was found to be reduced in methylcholanthrene induced fibrosarcoma rats after Muthu Marunthu treatment. Elevated levels of glycocomponents of glycoproteins such as hexose, hexosamine, sialic acid and fucose in plasma of fibrosarcoma rats decreased significantly after Muthu Marunthu treatment. The DNA and RNA levels of liver and kidney, which were increased in fibrosarcoma rats, returned to near normal levels after Muthu Marunthu treatment. The vitamins such as A, C and E in plasma were decreased in fibrosarcoma rats but increased significantly after Muthu Marunthu treatment. The altered levels of copper, zinc and selenium in plasma have also been corrected after Muthu Marunthu treatment. These observations clearly suggested the antitumor potency of Muthu Marunthu in experimentally induced fibrosarcoma in rats.

Dose-related effects of growth hormone on IGF-I and IGF-binding protein-3 levels in non-islet cell tumour hypoglycaemia

Mesenchymal tumours are a well recognised cause of spontaneous hypoglycaemia. The mechanism is thought to relate to hypersecretion by tumour cells of high molecular mass insulin-like growth factor-II (pro-IGF-II), with consequent suppression of growth hormone (GH) secretion. The use of recombinant human (rh)GH has been reported to alleviate hypoglycaemia in non-islet cell tumour hypoglycaemia, and the mechanism is thought to relate to GH-mediated increments in serum levels of IGF-binding protein-3 (IGFBP-3), thereby reducing the bioavailability of IGF-II. We report the effect of increasing doses of rhGH on the clinical condition and serum IGF-I and IGFBP-3 levels in two patients with solitary pleural fibrous tumours causing severe hypoglycaemia. Hypoglycaemia was successfully alleviated in each patient although, despite using large doses of rhGH, the observed increments in IGFBP-3 were only modest. We postulate that the beneficial effects of rhGH in this situation are likely to be multifactorial and not simply related to increments in serum IGFBP-3 levels.

Lovastatin inhibits tumor growth and metastasis development of a rat fibrosarcoma

HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, the rate limiting enzyme in cholesterol synthesis, catalyses mevalonate production and, hence, influence the synthesis of isoprenoid metabolites. It has already been demonstrated that products of the mevalonate pathway play an important role in the progress of the cell cycle and cell survival. Lovastatin (LOV) competitively inhibits HMG-CoA reductase, blocking the synthesis of mevalonic acid and the generation of non-sterol isoprenoids, such as farnesyl residues. The posttranslational farnesylation of p21ras protein is essential for its binding to the membrane and, therefore, for its transforming activity. Considering that p21ras protein was reported to have a significant rol in metastatic behavior of tumor cells, we decided to study LOV as an antimetastatic agent on a rat fibrosarcoma. We demonstrated that a short treatment with LOV diminished primary tumor growth and the number and size of lung experimental metastasis.

Activity of lysosomal and nonlysosomal proteases and contents of protein and its degradation products in the blood serum of rats with fibrosarcoma induced by methylcholanthrene

Activity of lysosomal and nonlysosomal proteases and contents of protein and its degradation products in the blood serum of rats with methylcholantrene fibrosarcoma were evaluated. Activity of lysosomal proteases and prolidase and prolinase as well in the blood serum of rats with methylcholanthrene tumour did not differ from the activity of these enzymes in the blood serum of control rats. Only the activity of elastase and collagenase in the blood serum of rats with methylcholanthrene tumour especially with tumour of intermediate and big mass was increased. Content of total protein was decreased in the blood serum of rats with tumour of intermediate and big mass and contents of glycoproteins and alfa-amin nitrogen were increased in comparison to the blood serum of control rats.

A serum-mediated mechanism for concomitant resistance shared by immunogenic and non-immunogenic murine tumours

Resistance of tumour-bearing mice to a second tumour challenge, that is concomitant resistance, was evaluated in euthymic and nude mice using nine tumours with widely different degrees of immunogenicity. Two temporally separate peaks of concomitant resistance were detected during tumour development. The first one was exhibited only by small immunogenic tumours; it was tumour specific and mediated by classical immunological T-cell-dependent mechanisms. The second peak was shared by both immunogenic and non-immunogenic large tumours; it was non-specific, thymus independent and correlated with the activity of a serum factor (neither antibody nor complement) that inhibited the in vitro proliferation of tumour cells. This factor was eluted from a Sephadex G-15 column at fractions corresponding to a molecular weight of approximately 1000 Da and it was recovered from a high-performance liquid chromatography column in one peak presenting maximum absorption at 215 and 266 nm. The data presented in this paper suggest for the first time, to our knowledge, that in spite of the differences between immunogenic and non-immunogenic tumours, a common serum-mediated mechanism seems to underlie the concomitant resistance induced by both types of tumours at late stages of tumour development.

Alpha-tocopherol ameliorates cyclophosphamide-induced hyperlipidemia in fibrosarcoma-bearing rats

Cyclophosphamide, an alkylating agent, is currently being used for the treatment of various types of cancer, either alone or in combination with other cytostatic drugs. However, cyclophosphamide has a detrimental effect on lipid metabolism and causes hyperlipidemia in patients. Since alpha-tocopherol is known to reduce hyperlipidemia, we have investigated the effects of adding alpha-tocopherol to the cyclophosphamide treatment. Our study, carried out on fibrosarcoma-bearing rats, shows that alpha-tocopherol markedly reduces cyclophosphamide-induced hyperlipidemia and brings lipid metabolism down to values observed in untreated controls.

Investigation of phagocyte-inducible factor in tumor-implanted mice

The number of spleen Mac-1-positive cells was markedly increased in methylcholanthrene-induced Meth-A fibrosarcoma (Meth-A)-implanted mice. When the sera of Meth-A-implanted mice were added to normal bone marrow cells, granulocyte and macrophage colony stimulating factor (GM-CSF)-dependent growth of bone marrow cells was significantly enhanced. Analysis of the Meth-A-implanted mice sera showed that the levels of serum transferrin were markedly elevated. When the sera of Meth-A-implanted mice were pretreated with anti-mouse transferrin antibody, the enhancement of GM-CSF-dependent cell growth was almost abolished. Cell growth was also stimulated by the addition of transferrin which also caused an increase in the number of Mac-1-positive cells. Analysis of the effect of transferrin on bone marrow cells showed that the response of the cells to GM-CSF was significantly increased by preincubation with transferrin.

Effect of administering cyclophosphamide and vitamin E on the levels of tumor-marker enzymes in rats with experimentally induced fibrosarcoma

Cyclophosphamide, and antineoplastic drug, and vitamin E, the common antioxidant present in the diet, were administered in separate dosages and in combination to animals (rats) with fibrosarcoma, metastatic tumor of the connective tissues, induced. The anticancer drug (20 mg/kg body weight) and the vitamin-E (400 mg/kg body weight) was administered for a period of 28 days from the day of tumor transplantation. The individual and the combined effects of these two substances were investigated by checking the growth of the tumor. Tumor markers like lactate dehydrogenase (LDH), serum glutamate pyruvate transminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), acid phosphatase, and alkaline phosphatase were analyzed for the changes in their concentration in serum, liver, and kidney to assess the success of the therapy. The increased level of the enzymes in the fibrosarcoma-suffering rats (GPII) was reduced by cyclophosphamide treatment (GP III) and vitamin E administration (GP IV). Among the treated groups, the combination therapy (GP V) showed greater efficacy in the treatment of fibrosarcoma than did individual administration, as there was more reduction in the levels of enzymes in Group V than those in to Groups III and IV. The enzyme levels were brought to near the normal level.

Effect of intralipid infusion on serum high- and low-density lipoprotein cholesterol, lecithin:cholesterol acyltransferase, and lipoprotein lipase in tumor-bearing rats

We compared the effects of 0.45% normal saline (NS), 5% Intralipid (IL), and 16.7% glucose (Glu) infusions on total serum triglycerides and cholesterol, serum high-(HDL-c) and low-density lipoprotein cholesterol (LDL-c), and activity of serum lecithin:cholesterol acyltransferase (LCAT), and serum lipoprotein lipase (LPL) in rats implanted with a fibrosarcoma. In tumor-bearing rats given NS, a two-fold increase in total serum cholesterol, a four-fold increase in LDL-c, and a five-fold decrease in the HDL-c/LDL-c ratio were observed compared to tumor-free rats. In tumor-bearing rats administered IL, a two-fold increase in total serum triglyceride and cholesterol, a three-fold increase in HDL-c and HDL-c/LDL-c ratio, and a two-fold increase in LPL activity were observed compared to tumor-bearing rats administered NS. In tumor-bearing rats administered Glu, a two-fold decrease in total serum cholesterol, a two-fold decrease in HDL-c, and a three-fold decrease in LDL-c were observed compared to tumor-bearing rats administered NS. Tumor weights and LCAT activity did not differ significantly between treatment groups. Previous results have demonstrated that lipophilic compounds that interact with plasma lipoproteins have altered pharmacological effects when administered with IL. Therefore, this study suggests that IL infusions alter the HDL-c/LDL-c ratio and could affect the pharmacological behavior of anticancer compounds that predominantly distribute into the LDL fraction upon entrance into the bloodstream.

Superoxide dismutase (SOD) activity with Fe-chlorin e6-Na and suppression of malignant tumor growth in rats

Derivatives of porphyrin, specifically Fe-chlorin e6-Na (FeCNa), mimic superoxide dismutase (SOD). This SOD activity was determined by decrease in electron spin resonance (ESR) signals and increase in hydrogen peroxide (H2O2) as the intermediate of O2-. by the coloration using 4-aminoantipyrin. Chlorin e6-Na used for cancer photodynamic therapy (PDT)(1) does not show SOD mimicking activity. The specific activity of FeCNa, comparing with bovine RBC-SOD, was 1/7.5 as determined by ESR analysis. The iron element of Fe-chlorin e6-Na, being tightly encased in the molecule, did not participate in the Fenton reaction. The SOD mimetic activity of FeCNa was stable against physico-chemical treatment such as pH shock, heat and digestion by pronase. For cancer bearing rats with oxidative stress (OS), immediate relief of OS was possible by a single intraperitoneal injection of FeCNa and relief continued for 24 hours. The subsequent administration of FeCNa suppressed cancer growth in vivo.

Coagulation activation by MC28 fibrosarcoma cells facilitates lung tumor formation

Tumor cells interact with the hemostatic system in various ways and may thus influence malignant growth and spread. MC28 fibrosarcoma cells possess a potent procoagulant activity (PCA) and form lung tumors following intravenous injection. The aim of this work was to study the relationship between PCA, intravascular coagulation and lung seeding in the MC28 model. MC28 cells were injected into control, warfarinized and heparinized hooded Lister rats. Coagulation changes were monitored by thromboelastography (TEG) and Sonoclot analysis (SA), lung fibrin formation by light and electron microscopy, tumor seeding by macroscopic counting and tumor cell and platelet deposition in the lungs by radiolabelling. PCA was measured by chromogenic assay. MC28 PCA was characterized as a tissue factor-factor VIIa complex that probably arose during cell culture or disaggregation of solid tumors. Injection of tumor cells caused marked coagulopathy and was rapidly (within 30 min) followed by fibrin deposition in the lungs and accumulation of radiolabelled platelets. Heparin and warfarin significantly reduced lung seeding (p < 0.001) and reduced retention of radiolabelled tumor cells in the pulmonary circulation (p < 0.01). Inhibition of cellular PCA by prior treatment with concanavalin A markedly reduced intravascular coagulation and lung seeding. We conclude that MC28 cells cause intravascular coagulation as a direct result of their procoagulant activity. The data suggest that tumor cells form complexes with platelets and fibrin which are retained in the lungs long enough for extravasation and seeding to occur.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of total and interstrand DNA adducts in tumor and kidney with antitumor efficacies and differential nephrotoxicities of cis-ammine/cyclohexylamine-dichloroplatinum(II) and cisplatin

Mixed amine platinum complexes have been identified as a new class of antitumor agents with activity in some cisplatin-resistant tumor models. cis-Ammine/cyclohexylamine-dichloroplatinum(II) is one such analog that we have evaluated in vivo and found it to have antitumor activity that was comparable to that of cisplatin in a solid murine fibrosarcoma tumor model. In contrast to the nephrotoxicity observed with cisplatin, the analog was free from inducing this side-effect. Pharmacokinetics of the two compounds administered i.v. at equitoxic dose levels to tumor-bearing mice indicated similar decay kinetics of total platinum in plasma, kidney and the tumor. Furthermore, DNA-platinum adducts of the two agents were similar in the tumor. Total adduct levels in the kidney, on the other hand, were significantly greater (P < 0.5) by up to 4-fold for cisplatin compared with the mixed amine analog. Likewise, the levels of interstrand cross-links of the two platinum complexes were comparable in the tumor, but significantly greater (P < 0.05) in the kidney for cisplatin. The data indicate that the greater renal levels of total and interstrand DNA-platinum adducts formed by cisplatin correlate with renal damage associated with this agent, and suggest that adduct levels, and not total tissue platinum levels, provide a more useful correlation with pharmacodynamic observations.

Procoagulant activity of the MC28 fibrosarcoma cell line in vitro and in vivo

Experimental evidence suggests that many tumours can activate blood coagulation and that such interaction is part of the pathology of metastatic tumour growth. This study aimed to study the procoagulant activity of the methylcholanthrene-induced (MC28) fibrosarcoma to determine whether coagulation activation by these cells could explain the previously reported effects of oral anticoagulants on lung seeding in this model. MC28 cells shortened the recalcification times of normal and factor VII-deficient plasma and directly activated factor X in a chromogenic assay, but did not aggregate platelets in vitro in either whole blood or platelet-rich plasma. Cellular coagulant activity was calcium-dependent, blocked by DFP and concanavalin A but not inhibited by iodoacetamide, E-64 or antibodies to human tissue factor or factor VII. Injection of viable MC28 cells into hooded Lister rats induced a decrease in platelet count (P < 0.001), plasma factor X (P < 0.001) and fibrinogen (P < 0.05) and a marked increase in plasma haemoglobin (P < 0.001). These effects were either not observed or were considerably less marked in heparinized or warfarinized animals. Injection of MC28 cells treated with concanavalin A in vitro completely abolished the clotting changes observed with untreated cells. In conclusion, MC28 cells possessed a potent factor X-activating serine proteinase procoagulant in vitro, which had some of the characteristics of a tissue factor/factor VIIa complex. In vivo, MC28 cells caused clotting activation and intravascular fibrin generation. Since thrombocytopenia was abolished by heparin and the cells lacked platelet aggregating activity in vitro, thrombocytopenia was probably secondary to intravascular coagulation and thrombin generation. The trigger for intravascular clotting activation appeared to be the cellular procoagulant activity since it was abolished by prior in vitro blockade of the latter with concanavalin A.

[Differences in antitumor effect of various BRMs by intratumoral administration: induction of immunosuppressive acidic protein]

The antitumor effects of biological response modifiers (BRM) in a new experimental mouse model, the "double grafted tumor system", were analysed. BALB/c mice received simultaneous inoculations of Meth-A fibrosarcoma cells on right flank (10(6) cells) and left flank (2 x 10(5) cells) on day 0, and BRMs were injected intratumorally into right tumor on day 3, 4 and 5. The growth of the left-flank tumor was the real target for the evaluation of a given drug after 21 days. PSK (a protein-bound polysaccharide preparation), IL-1 and Cepharanthin, cured not only the right, but also the left, non-treated tumor in a double grafted tumor system. OK-432 (a Streptococcus preparation) and BCG cured the right tumor and inhibited the growth of the left tumor. Lentinan (a polysaccharide preparation) inhibited neither the right nor the left tumor. Immunosuppressive acidic protein (IAP) in serum was increased transiently soon after intradermal injection of PSK, OK-432 and TNF in BALB/c mice. But Lentinan did not induce IAP. IAP in serum was gradually increased after intradermal inoculation of Meth-A tumor in BALB/c mice. At 21 days after tumor inoculation, IAP in serum reached a maximum level (300 micrograms/ml). The serum IAP level of Meth-A-bearing mice as well as that of normal mice increased after the intratumoral injection of PSK. At 21 days after tumor inoculation, IAP in PSK-treated mice returned to normal level. The biochemical differences between PSK-induced IAP (early, inflammatory IAP) and Meth-A-induced IAP (late, tumor-induced IAP) was investigated by crossed immunoaffino electrophoresis (CIAE). Inflammatory IAP was rich in biantennary sugar chain, and tumor-induced IAP was rich in tri-tetraantennary sugar chain.

Serum "big insulin-like growth factor II" from patients with tumor hypoglycemia lacks normal E-domain O-linked glycosylation, a possible determinant of normal propeptide processing

The insulin-like growth factor II (IGF-II) gene is overexpressed in many mesenchymal tumors and can lead to non-islet-cell tumor hypoglycemia (NICTH). ProIGF-II consists of the 67 aa of IGF-II with a carboxyl 89-aa extension, the E domain. A derivative of proIGF-II containing only the first 21 aa of the E domain [proIGF-II-(E1-21)] has been isolated by others from normal serum and has O-linked glycosylation. We found that the "big IGF-II" of normal serum, as detected by an RIA directed against residues 1-21 of the E domain of proIGF-II, was reduced in size by treatment with neuraminidase and O-glycosidase. The big IGF-II, which is greatly increased in NICTH sera, was unaffected by neuraminidase and O-glycosidase treatment. We have also shown that big IGF-II from normal serum is retained by jacalin lectin columns and that big IGF-II from NICTH serum was not retained, indicating that it lacked O-glycosylation. Normal O-linked glycosylation may be required for proper peptidase processing of proIGF-II. The lack of normal O-linked glycosylation by tumors may explain the predominance of big IGF-II in NICTH sera. In normal serum, most of the IGF-II is present in a 150-kDa ternary complex with IGF-II binding protein (IGFBP) 3 and alpha subunit. In NICTH serum, however, the complexes carrying big IGF-II are < 50 kDa. We investigated whether big IGF-II of NICTH was responsible for this abnormality. Tumor big IGF-II and IGF-II were equally effective in forming the 150-kDa complex with purified IGFBP-3 and 125I-labeled alpha subunit. Both 125I-labeled IGF-II and 125I-labeled proIGF-II-(E1-21), when incubated with normal serum, formed the 150-kDa complex as detected by Superose 12 exclusion chromatography. We conclude that the nonglycosylated big IGF-II of NICTH serum can form normal complexes with serum IGFBPs. The defective binding in NICTH is attributable to defective IGFBP-3 binding.

Differential induction of prostaglandin E2-dependent and -independent immune suppressor cells by tumor-derived GM-CSF and M-CSF

Both prostaglandin E2 (PGE2)-dependent (indomethacin-sensitive) and PGE2-independent (indomethacin-insensitive) suppressor cell activities that inhibited mitogenic T cell blastogenesis appeared in the bone marrow and spleen of mice on days 20 to 30 following transplantation of NFSA fibrosarcoma molecularly expressing mRNA for both macrophage (M) and granulocyte-macrophage (GM) colony-stimulating factors (CSFs). The present study was done to characterize the two different suppressor cells isolated from NFSA tumor-bearing mice and to verify a role of CSFs in the induction of suppressor cells in vitro. Whereas PGE2-releasing suppressor cells were found in bone marrow and spleen cells isolated from tumor-bearing mice, indomethacin-insensitive suppressor cells in both tissues were localized predominantly in adherent cell fractions. An increase in Mac-1+ and Mac-2+ spleen cell populations with two to three times larger cell volumes was observed, and both showed strong PGE2-releasing capacity and indomethacin-sensitive suppressor cell activity. However, after elimination of Mac-1+ or Mac-2+ cells, bone marrow cells still showed higher PGE2-releasing capacity and indomethacin-sensitive suppressor activity. The in vitro cultures of normal bone marrow and spleen cells with NFSA cell conditioned medium (NFSA-CM) induced heterogeneous mixtures of indomethacin-sensitive and - insensitive suppressor cells like those observed in cultures with the combination of M-CSF and GM-CSF. However, cultures with either GM-CSF or M-CSF resulted in the induction of indomethacin-sensitive suppressor cells by GM-CSF and of indomethacin-insensitive suppressor cells by M-CSF. In addition, NFSA-CM pretreated with anti-GM-CSF antibody induced indomethacin-insensitive suppressor cells in in vitro cultures of bone marrow and spleen cells. These results suggest that two distinctly different suppressor cells developed under hemopoiesis of myelomonocytic lineage cells are regulated differentially by the two macrophage growth factors, M-CSF and GM-CSF.

The production of a factor X activator by a methylcholanthrene-induced rat fibrosarcoma

The association between neoplasia and thrombosis has been well documented. We have studied the production of a procoagulant which is a factor X activator in a rat fibrosarcoma model. Extracts of excised tumor were assayed in a one stage clotting assay using normal and factor deficient human plasmas. The activity was not due to tissue factor, as acceleration of clotting was observed in FVII deficient plasma. No activity was noted in FX deficient plasma. The activator was capable of cleaving 125I-FX in the absence or presence of calcium. A radioimmunoassay (RIA) demonstrated a 5,100-fold increase in the levels of FX activation peptide after exposure to sarcoma extract. The FX activation occurs in the absence of calcium although the effect is greatly accelerated in the presence of 5 mM CaCl2. Using a two-stage amidolytic assay, functional activation of FX by the sarcoma was demonstrated. Inhibitor studies suggest that the sarcoma-derived procoagulant is a serine protease. The methylcholanthrene-induced rat sarcoma may serve as a useful model for investigating the regulation and effects of cancer procoagulants.

The effects of glutamine-enriched total parenteral nutrition on tumor growth and host tissues

The effects of glutamine-enriched total parenteral nutrition (TPN+GLN) were studied in tumor-bearing rats because glutamine can benefit host tissues but also may stimulate tumor growth. Rats were implanted with the methylcholanthrene-induced fibrosarcoma (MCA sarcoma) and were studied when the tumor constituted less than 5% of carcass weight (small tumor) and when the tumor constituted 10% of carcass weight (large tumor). Provision of 20% of TPN protein as glutamine produced a significant increase in the arterial glutamine level and maintained the skeletal muscle intracellular glutamine concentration (2.02 +/- 0.1 versus 1.39 +/- 0.07 mumol/g, p less than 0.01). Concurrently, hindquarter GLN fractional release increased nearly threefold (p less than 0.05) in the TPN+GLN group. Glutamine-enriched total parenteral nutrition did not affect carcass weight, tumor weight, tumor DNA content, or tumor glutaminase activity. Furthermore, DNA flow cytometric analysis did not demonstrate any difference in percentage of aneuploid tumor cells within the G1, S, or G2M cell cycles. However, the ratio of aneuploid to diploid cells within the tumor mass increased by 20% in animals receiving glutamine. Glutamine-enriched total parenteral nutrition had no effect on tumor glutathione (GSH) levels. No increase in hepatic GSH levels was observed, but gut mucosal GSH levels were 20% greater in the TPN+GLN group (p less than 0.05). The provision of glutamine-enriched TPN may be beneficial to the host by maintaining skeletal muscle glutamine stores and by supporting gut GSH biosynthesis. In this tumor model, TPN+GLN does not appear to increase tumor size, tumor DNA content, or tumor glutamine metabolism, but the ratio of tumor cells to host infiltrating cells within the tumor mass appears to be increased.

Alleviation of autoimmune disease by dietary lipids containing omega-3 fatty acids

Dietary marine lipids that are enriched in omega-3, or n-3, fatty acids reduce the severity of autoimmune glomerulonephritis in several inbred murine strains. The protective effect of dietary n-3 fatty acids is also seen with a rat model of immune-complex induced vasculopathy, but no protective effects were seen with autoimmune vasculitis in the MRL/lpr mouse or with type II collagen-induced arthritis in rats. Dietary n-3 fatty acids are potential therapeutic agents for the treatment of autoimmune diseases, but careful clinical trials with the purified forms of n-3 fatty acids are needed to determine the usefulness of this intervention.

In vivo tumor growth enhancement by granulocyte colony-stimulating factor

The intraperitoneal administration of human recombinant granulocyte colony-stimulating factor (G-CSF) enhanced the growth of intradermally inoculated tumor in mice; in a Meth A fibrosarcoma model, G-CSF administration significantly shortened the latency before tumor appearance, accelerated the increase of tumor size, shortened the survival time of tumor-bearing mice and increased the incidence of lethal tumor growth. A similar growth-enhancing effect of G-CSF was observed in models employing Meth 1 fibrosarcoma, colon carcinoma 26, and L1210 leukemia, although not all the effects were statistically significant. In vitro study showed that G-CSF did not enhance Meth A growth in suspension culture or in soft agar. These data suggest that G-CSF enhances the Meth A growth not directly but through the mediation of host factors. The accumulation of neutrophils was histologically observed in the tumor nodule, the blood, and the spleen in mice given G-CSF repeatedly. The spleen cells and the peripheral blood leukocytes of G-CSF-injected mice enhanced Meth A growth in vitro as compared with those of mice injected with physiological saline. These results suggest the possibility that the in vivo growth of tumor cells was enhanced by G-CSF-induced overproduction of cells including neutrophils.

Modulation of hematopoietic colony formation of stem cells in peripheral blood by anti-TGF-beta in patients with severe immunosuppression

The influence of transforming growth factor-beta (TGF-beta) on hematopoiesis has been evaluated by adding blocking antibodies against TGF-beta to colony forming assays (CFU-c). When optimum concentrations of recombinant growth factors, granulocyte-macrophage colony stimulating factor (GM-CSF), and interleukin-3 (IL-3) were added to stem cells from the peripheral blood of healthy individuals and certain patients with tumors or HIV infection, the anti-TGF-beta capable of blocking 5 ng/ml of active TGF-beta had no significant influence on erythroid or myeloid colony formation. However, in certain immunosuppressed individuals, anti-TGF-beta resulted in a significant decrease of erythroid colony formation and slight suppression of myeloid colony formation. The significant inhibition of hematopoiesis by plasma of HIV patients could be due to the presence of active forms of TGF-beta. The results of the blocking experiments are consistent with the concept that TGF-beta in low concentrations is essential for erythropoiesis and myelopoiesis but that higher levels of TGF-beta primarily inhibit erythropoiesis in vitro. TGF-beta serves as a coordinating factor when efficient recruitment of granulocytes and monocytes is more essential than erythropoiesis and stem cell growth.

The effect of cis-diamminedichloroplatinum(II) treatment at elevated temperatures on murine fibrosarcoma, FSa-II

The effect of cis-diamminedichloroplatinum(II) (cis-DDP) on the murine fibrosarcoma cells was investigated in vitro and in vivo. For in vitro experiments tumour cell suspensions containing a given amount of cis-DDP were treated in water bath maintained at a desired temperature, and cell survival was determined by the lung colony assay. The D0 or the time to reduce survival from 1.0 to 0.37 on the exponential portion of the survival curve was determined and 1/D0 was plotted as a function of 1/T, where T stands for the absolute temperature. The slope of this Arrhenius plot indicated that the activation energy for chemical reaction of cis-DDP was 44 kcal/M between the temperature range from 37 to 41 degrees C. For in vivo experiments tumours were transplanted into the foot and treated by immersing the animal foot into a water bath when each tumour reached an average diameter of 4 mm (35 mm3). The drug was injected i.p. immediately before hyperthermia. The tumour growth (TG) time or the time required for a tumour to reach 1000 mm3 from the treatment day was determined, and the median TG time was obtained by logit analysis. Dose-response curves between the TG time and drug dose indicated that the cytotoxic effect of cis-DDP was enhanced at elevated temperatures. This enhancement increased with increasing temperature from room temperature to 43.5 degrees C. Because of short plasma half-time of cis-DDP, continuous infusion and pulse injections were attempted.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of parenteral nutrition on tumor growth and erythrocyte polyamine levels in the rat

The influence of total parenteral nutrition (TPN) on tumor growth and erythrocyte polyamine levels was evaluated in rats with a transplantable fibrosarcoma or a Ward colon tumor. During the experimental periods the fibrosarcoma grows exponentially when rats are fed chow ad libitum while the colon tumor reaches a plateau of its Gompertzian growth curve. A 12-day regimen of TPN resulted in an increased growth of the colon tumor but not the fibrosarcoma. The erythrocyte putrescine levels of fibrosarcoma-bearing rats and the levels of putrescine, spermidine, and spermine of Ward colon-tumor-bearing rats were significantly increased by TPN compared with similarly treated nontumor-bearing (NTB) rats. When the growth of the fibrosarcoma was slowed by feeding a restricted intake (RI) regimen, a subsequent 6-day regimen of TPN resulted in increased tumor growth. Erythrocyte polyamine levels of fibrosarcoma-bearing, RI-rats were elevated by TPN repletion. There was a consistent, significant, interaction between TPN and tumor presence on the erythrocyte putrescine levels in fibrosarcoma-bearing rats and the levels of all polyamines in Ward colon-tumor-bearing rats. The effects of TPN on tumor growth and erythrocyte polyamine levels of tumor-bearing rats may be dependent on the growth characteristics of the tumor. The data demonstrate that TPN consistently enhanced the tumor contribution to the erythrocyte putrescine pool.

Significance of abnormal serum binding of insulin-like growth factor II in the development of hypoglycemia in patients with non-islet-cell tumors

We reported that serum and tumor from a hypoglycemic patient with a fibrosarcoma contained insulin-like growth factor II (IGF-II), mostly in a large molecular form designated "big IGF-II." We now describe two additional patients with non-islet-cell tumor with hypoglycemia (NICTH) whose sera contained big IGF-II. Removal of the tumor eliminated most of the big IGF-II from the sera of two patients. Because specific IGF-binding proteins modify the bioactivity of IGFs, the sizes of the endogenous IGF-binding protein complexes were determined after neutral gel filtration through Saphadex G-200. Normally about 75% of IGFs are carried as a ternary complex of 150 kDa consisting of IGF, a growth hormone (GH)-dependent IGF-binding protein, and an acid-labile complexing component. The three patients with NICTH completely lacked the 150-kDa complex. IGF-II was present as a 60-kDa complex with variable contributions of smaller complexes. In the immediate postoperative period, a 110-kDa complex appeared rather than the expected 150-kDa complex. Abnormal IGF-II binding may be important in NICTH because the 150-kDa complexes cross the capillary membrane poorly. The smaller complexes present in our patients' sera would be expected to enter interstitial fluid readily, and a 4- to 5-fold increase in the fraction of IGFs reaching the target cells would result.

Interorgan glutamine metabolism in the tumor-bearing rat

The effects of progressive malignant disease on gut/liver glutamine metabolism were studied in order to gain further insight into the altered glutamine metabolism that characterizes the host with cancer and to further elucidate the causes and consequences of glutamine depletion in tumor-bearing rats. Rats were inoculated on Day 0 with 2 X 10(6) viable fibrosarcoma cells and blood glutamine was measured every 6 days. On Day 24 the animals underwent laparotomy and sampling of arterial, portal venous, and hepatic venous blood. Arterial glutamine fell by more than one-third in tumor-bearing rats and the arterial-portal venous concentration difference for glutamine across the intestinal tract was diminished by 50% (P less than 0.01). Simultaneously the fractional extraction of glutamine by the gut was reduced from 21 to 15% (P less than 0.05). The liver switched from an organ of near glutamine balance in control rats to one of marked glutamine output in tumor-bearing rats (P less than 0.01). The wet weight of the small intestine was diminished by 15% in tumor-bearing rats and villous height was uniformly decreased in tumor-bearing rats with an average reduction in villous height of 26% (P less than 0.05). The causes of glutamine depletion in this tumor-bearing rat model remain unclear. The growing tumor may behave as a glutamine trap but also appears to alter glutamine metabolism in vital metabolic processing centers such as the gut and liver. Malignant cells may compete with gut mucosal cells for glutamine resulting in a diminished gut glutamine utilization and detrimental changes in mucosal architecture.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic studies with zinc(II)-phthalocyanine in tumour-bearing mice

Zn(II)-phthalocyanine (Zn-Pc) incorporated into unilamellar liposomes of dipalmitoylphosphatidylcholine has been injected intraperitoneally (0.5 mg kg-1) to BALB/c mice bearing a transplanted MS-2 fibrosarcoma. The drug is specifically transported by serum lipoproteins and cleared from the serum via the bile-gut pathway in a biphasic process: approximately 60% of Zn-Pc is eliminated with a serum half-life of approximately 9 hours, while the remaining aliquot is eliminated at a very slow rate. Several normal tissues take up the drug within 3 hours after administration but release it almost completely after 24-48 hours. On the other hand, the tumour shows a maximum concentration of Zn-Pc (approximately 0.6 microgram g-1 of tissue) after 18-24 hours; at this time, the ratio between the Zn-Pc levels in the tumour and the muscle (which represents the surrounding normal tissue) is approximately 7.5. The results are discussed in terms of a possible use of Zn-Pc as a photosensitizer in the photodynamic therapy of tumours.

Growth of an implanted fibrosarcoma in rats is associated with high levels of plasma prostaglandin-E2 and thromboxane-B2

Growth of BN175, a malignant fibrosarcoma, was correlated with high plasma TXB2 and PGE2 levels. This statistically significant increase was first detected 17 days after inoculation of the tumor, at which time the tumors were 20 mms in diameter. A further increase in tumor size was associated with still higher PGE2 and TXB2 values. At the same time, progressive alterations in platelet function, as measured by ADP-induced platelet aggregation, were observed. 6-keto-PGF1 alpha levels remained normal throughout the whole experiment. It was concluded that tumor growth was associated with changes in PG synthesis and platelet function, although it remains unclear whether these changes were caused by some host immunological response towards the tumor or were predominantly the result of tumor PG-synthesis.

Relationship of erythrocyte polyamine levels and growth rate of transplantable tumors in rats

Varying levels of polyamines in the urine, plasma, and erythrocytes (RBC) of cancer patients have been demonstrated. The growth rate of the tumor has been suggested as a primary factor which determines whether the polyamine levels in urine are elevated. To further evaluate tumor size and growth rate as variables affecting polyamine levels in physiological fluids, the effect of a transplantable fibrosarcoma and colon tumor on the RBC polyamine levels of Fischer 344 rats was determined. The tumors were implanted s.c. and grew without metastasis or spontaneous regression. The fibrosarcoma grew exponentially up to a weight of approximately 69 +/- 15 (SD) g and was associated with a linear increase in RBC polyamine levels compared with that of non-tumor-bearing rats. RBC putrescine, spermidine, and spermine levels were significantly elevated at tumor weights of 12.5 +/- 1.4, 20.4 +/- 3.8, and 33.2 +/- 5.0 g, respectively. The respective polyamines increased consistently thereafter until the tumor weight was 57.8 +/- 5.8 g. In contrast with the fibrosarcoma, the colon tumor grew exponentially only to a weight of 9.2 +/- 4.7 g, at which time the growth rate of the tumor began to decrease (time T of the Gompertz model). RBC polyamine levels of rats with the colon tumor showed only a transient increase. RBC putrescine levels were significantly increased at a tumor weight of 12.9 +/- 1.2 g and spermidine at a tumor weight of 17.4 +/- 0.2 g. RBC spermine levels were significantly elevated at both tumor weights; thereafter, all RBC polyamine levels returned to normal. Host cachexia was evident when the fibrosarcoma and colon tumors weighed 12.5 +/- 0.9 and 7.2 +/- 2.6 g, respectively. The polyamine levels of the fibrosarcoma differed significantly from that of the colon tumor. These levels, however, did not correlate with the exponential growth rates. The results suggest that the tumor is the major source of elevated RBC polyamines. The data also suggest that the tumors must be rapidly growing for the elevation in polyamines to occur. This may partly explain why patients with extensive neoplastic disease that may have surpassed time T in the Gompertz model do not manifest abnormal polyamine levels.