Targeted hyperthermia using magnetite cationic liposomes and an alternating magnetic field in a mouse osteosarcoma model.

We undertook a study of the anti-tumour effects of hyperthermia, delivered via magnetite cationic liposomes (MCLs), on local tumours and lung metastases in a mouse model of osteosarcoma. MCLs were injected into subcutaneous osteosarcomas (LM8) and subjected to an alternating magnetic field which induced a heating effect in MCLs. A control group of mice with tumours received MCLs but were not exposed to an AMF. A further group of mice with tumours were exposed to an AMF but had not been treated with MCLs. The distribution of MCLs and local and lung metastases was evaluated histologically. The weight and volume of local tumours and the number of lung metastases were determined. Expression of heat shock protein 70 was evaluated immunohistologically. Hyperthermia using MCLs effectively heated the targeted tumour to 45 degrees C. The mean weight of the local tumour was significantly suppressed in the hyperthermia group (p = 0.013). The mice subjected to hyperthermia had significantly fewer lung metastases than the control mice (p = 0.005). Heat shock protein 70 was expressed in tumours treated with hyperthermia, but was not found in those tumours not exposed to hyperthermia. The results demonstrate a significant effect of hyperthermia on local tumours and reduces their potential to metastasise to the lung.

Anti-metastatic gene therapy utilizing subcutaneous inoculation of EC-SOD gene transduced autologous fibroblast suppressed lung metastasis of Meth-A cells and 3LL cells in mice.

We have previously reported that superoxide stimulates the motility of tumor cells and the administration of Cu-Zn superoxide dismutase (SOD) significantly suppresses metastasis. However, ideally, anti-metastatic therapy should be long-lasting, systemically effective and have low toxicity. The half-life of Cu-Zn SOD in plasma is so short that it cannot provide long-lasting effects. Therefore, in this study we have developed a gene therapy in a mouse model utilizing extracellular SOD (EC-SOD), which is the most prevalent SOD isoenzyme in extracellular fluids. We retrovirally transfected fibroblasts (syngeneic) with the EC-SOD gene and established EC-SOD-secreting fibroblasts. Inoculation of EC-SOD-secreting fibroblasts suppressed both artificial and spontaneous metastatic lung nodules in mouse metastasis models. These data indicate the feasibility of anti-metastatic gene therapy utilizing the EC-SOD gene.

Anticancer activity of rViscumin (recombinant mistletoe lectin) in tumor colonization models with immunocompetent mice.

The antitumoral and immunostimulating properties of rViscumin (recombinant mistletoe lectin) were investigated in two mouse tumor models. After intravenous inoculation with RAW-117-P or L-1 sarcoma cells in Balb/c mice, rViscumin was given s.c. at non-toxic doses ranging from 0.3 to 150 ng rViscumin/kg. One set of experiments was performed to investigate the survival of rViscumin-treated animals. Another set was carried out to analyze the effect of rViscumin treatment on the number of tumor colonies in infiltrated lungs (RAW-117P) or liver (L-1) and the activation of immune cell subsets, respectively. An overall prolonged survival time after treatment with rViscumin and a reduction in the number of tumor colonies after administration of certain rViscumin doses was observed. Immunophenotyping of the peripheral leukocytes of treated mice revealed increased numbers of T-lymphocytes, pan-NK cells and activated monocytes. The results indicate that rViscumin has antineoplastic properties and might therefore be a promising candidate in cancer therapy.

Pulmonary artery perfusion of doxorubicin with blood flow occlusion: pharmacokinetics and treatment in a metastatic sarcoma model.

BACKGROUND: We compared pharmacokinetics, toxicity, and treatment efficacy of pulmonary artery perfusion of low-dose doxorubicin with blood flow occlusion to intravenous doxorubicin injection in a metastatic sarcoma model in the rat. METHODS: Animals received left pulmonary artery perfusion with 0.1, 0.2, or 0.5 mg/kg doxorubicin at a rate of 0.1 mL/min for 1 minute with 20 minutes of blood flow occlusion. Doxorubicin levels of the lung, heart, and serum were assayed. Body weights after treatment were recorded and right pneumonectomy was performed. The results were compared with those in rats that received 5 mg/kg doxorubicin by intravenous injection or the saline group. Pulmonary sarcoma metastases were treated with 0.5 mg/kg doxorubicin through lung perfusion or intravenously, or with saline solution. RESULTS: Doxorubicin levels in the lung, heart, and serum were 112.1 +/- 9.2 micrograms/g, 1.7 +/- 0.2 microgram/g, and 0.3 +/- 0.1 microgram/mL in the group with 0.5 mg/kg doxorubicin perfusion, versus 24.8 +/- 1.9 microgram/g, 10.1 +/- 1.3 microgram/g, and 0.7 +/- 0.2 microgram/mL in the intravenous group (p < 0.05). Animals had normal growth patterns and survived after right pneumonectomy in the perfused group, whereas the intravenous group failed to thrive. No tumors were found or a significant reduction in nodules was noted in the lungs treated with perfusion as compared with untreated right lungs or the intravenous and saline groups. CONCLUSION: This chemotherapy model has important pharmacokinetic advantages and causes an increased treatment response for pulmonary metastatic sarcoma with minimal systemic and local toxicity as compared with systemic doxorubicin administration.

Combined hyperthermia and immunotherapy treatment of multiple pulmonary metastases in mice.

The combination of immunotherapy and hyperthermia results in a greater reduction in tumour growth compared to either therapy used alone in a murine subcutaneous tumour model. To evaluate this combination further we tested it in a murine pulmonary metastasis model. Mice were given 5 x 10(5) MCA-105 sarcoma cells on day 0 intravenously resulting in the formation of pulmonary metastases. Mice were treated with local hyperthermia to the left hemithorax with a transcutaneous microwave applicator or with whole-body hyperthermia to 41 degrees C for 30 min on days 3 and 6. Immunotherapy included 5 x 10(7) syngeneic LAK cells administered on days 3 and 6 and interleukin-2 given intraperitoneally three times daily on days 3-7. Animals were killed on day 12 and pulmonary nodules enumerated. While the addition of whole-body hyperthermia to immunotherapy had no significant effect on tumour growth, the combination of local hyperthermia and immunotherapy significantly decreased the number of pulmonary nodules by 94% compared to controls in combined experiments. The mechanism of this beneficial effect may be related to increased trafficking of immune active cells to the tumour-bearing site, an increase in the sensitivity of tumour cells to lysis, or perhaps a local release of cytokines induced by hyperthermia. This study established the efficacy of combined immunotherapy and hyperthermia for the treatment of visceral metastases and provides impetus for the initiation of clinical trials.

gamma-Interferon plays a key role in T-cell-induced tumor regression.

Recent studies have demonstrated that noncytolytic T-cells can mediate regression of murine tumors. In this report, we demonstrate that MCA-105 tumor-draining lymph node cells (DLN) activated with the protein kinase C activator, bryostatin 1, plus a calcium ionophore are capable of inducing specific tumor regression in vivo when adoptively transferred to mice with established metastases. However, these activated DLN cells lack in vitro cytotoxicity against autologous tumor. Antibody against gamma-interferon (IFN-gamma) markedly inhibited the therapeutic efficacy of these activated DLN cells. Anti-tumor necrosis factor produced a statistically significant but weaker inhibition of tumor regression. IFN-gamma, but not tumor necrosis factor alpha, could be shown to be secreted by activated DLN cells in vitro in response to specific tumor. Secretion of IFN-gamma was primarily a function of CD8+ T-cells. IFN-gamma was not directly cytotoxic to sarcoma cells in vitro. Moreover, tumor cells incubated with IFN-gamma were not more susceptible to lysis by activated DLN cells. However, recombinant murine IFN-gamma had a significant antiproliferative effect against MCA-105 tumor cells when tested in a [3H]thymidine uptake assay. Similarly, supernatants obtained from DLN/autologous tumor cocultures markedly inhibited MCA-105 proliferation; this antiproliferative effect was abrogated by the addition of anti-IFN-gamma antibody to the cultures. These results suggest that secretion of IFN-gamma by adoptively transferred DLN cells plays an essential role in tumor rejection. The dominant effect of IFN-gamma may be its demonstrated antiproliferative activity.

Effect of thermoimmunotherapy with OK-432 on the development of spontaneous lung metastases in mice.

The effect of combined hyperthermia and intratumoral administration of OK-432 (Picibanil) on the development of spontaneous lung metastases was studied. The spontaneous non-immunogenic fibrosarcoma, FSa-II, transplanted into the right foot of C3Hf/Sed mice, was used throughout. Hyperthermia was given locally by immersing the animal foot in a water bath set at 44.0 degrees C for 30 min. OK-432 in the dose of 2.5 KE was injected into the tumour 3 h before hyperthermia. This treatment has been shown to strongly inhibit local tumour growth. Sham hyperthermia, i.e. restraining the mice in holders, as well as local injection of saline solution, increased metastases incidence. The high incidence of metastases following combined sham hyperthermia and saline injection was substantially reduced by intratumoral administration of OK-432 given alone or combined with hyperthermia.

Consequences of blood loss on growth of artificial metastases.

Previous studies have shown that lung metastases from a nonimmunogenic sarcoma (LS175) in BN (homozygous for RTln) rats were stimulated by blood transfusions. Enhanced growth was also observed after abdominal surgery combined with allogeneic blood transfusions while syngeneic blood transfusions had no effect. These experimental findings have been confirmed in retrospective clinical studies. The allogeneic blood transfusion effect may be avoided in cancer patients by autologous blood transfusions although this implies blood donation before surgery. The aim of the present study was to investigate the effect of blood loss before surgery on formation ('take') of lung colonies, and on the outgrowth of established metastases in the BN rat model. These aspects of tumour behaviour were also investigated in rats undergoing surgery, or receiving blood transfusion, or both, after blood loss. The results indicate that blood loss has a profound stimulating effect on the growth of established metastases, but not on the 'take' of tumour cells. This stimulating effect was also present when blood loss was combined with surgery, while previously surgery alone was found to have no effect. Allogeneic and syngeneic transfusions in combination with blood loss both had a strong stimulating effect on growth of established lung metastases. The results indicate that blood loss may be an important factor in determining the outcome of metastatic growth.

[Action of doxorubicin and a doxorubicin-heparin complex on the growth and metastasis of experimental tumors and the hemostatic system indices]. / Deistvie doksorubitsina i kompleksa doksorubitsin--geparin na rost i metastazirovanie éksperimental'nykh opukholei i nekotorye pokazateli sistemy gemostaza.

The electrophoretic and spectral analyses have been used to show the possibility to form a complex consisting of doxorubicin and adriamycin with heparin, the molar ratio being 6:1 and pH 4.8-7.4. Doxorubicin and adriamycin had procoagulant properties but the doxorubicin-heparin complex showed an anticoagulant activity. In experiments on rats with the Pliss lymphosarcoma and sarcoma 45 the doxorubicin-heparin complex depressed more efficiently the tumour growth and metastasis spreading. The combination of doxorubicin and the doxorubicin heparin complex with the trypsin-heparin complex which imitate the hyperfunction of anticoagulative system markedly increased the antitumour effects.

Effect of X-rays and cyclophosphamide on solid tumors and naturally occurring metastases in mice.

Combinations of single doses of X-rays given locally to a transplanted tumor and single i.p. doses of cyclophosphamide (CY) were tested in mice bearing solid transplanted fibrosarcomas. The end points examined were growth delay and local control of the implanted tumor, the incidence of distant metastases, and survival times free of either local recurrence or metastases. Growth delay and local control increased more steeply with X-ray dose than with dose of CY. From 8 to 10 days of extra regrowth delay required only 10 to 20% extra X-ray dose, but it required a doubling of CY dose from three-eighths to three-fourths of the maximum tolerated dose. The incidence of metastases and the survival time of the mice also depended more upon the local dose of X-rays than that of CY. This result was not expected and suggests that metastases are eliminated more certainly if the primary (implanted) tumor is locally controlled on a long-term basis. A significant proportion of mice, over 50%, was cured of both the transplanted tumor and distant metastases only when the highest doses of both X-rays and CY were given simultaneously. Extended intervals between the two agents gave inferior results, intervals of 8 days giving significantly worse results, but 4 days giving not significantly worse results than simultaneous administration, especially when the X-ray treatment was given first. The interval of 4 days would, however, be sufficient to avoid the enhancement of radiation injury in normal tissues in mice.