Increased incidence of pulmonary metastases after celiotomy: counteraction by heparin

Early events of hepatic metastasis formation in mice: role of Kupffer and NK-cells in natural and interferon-gamma-stimulated defense

Surgical manipulation of a tumor may result in increased influx of tumor cells into the systemic and portal circulation and give rise to formation of metastases. In addition, major surgery has been reported to cause profound immunosuppression. In an attempt to increase the host-antitumor immune mechanisms following surgery we have studied the effect of preoperative administration of interferon-gamma, related to the antimetastatic effects of Kupffer cells (KC) and natural killer cells (NK-cells) in the early phase of liver metastasis formation. Colon carcinoma cells were injected into the superior mesenteric vein of syngeneic mice and after 17 days metastases were quantified by weight, number, and uptake of [125I]iododeoxyuridine. Unstimulated control mice developed 10.5 surface nodules per liver 17 days following injection of colon carcinoma cells into the superior mesenteric vein of syngeneic mice. This figure was only 2.6 in mice stimulated with a single dose of 1000 IU IFN-gamma 4 h prior to inoculation of tumor cells. Administration of GdCl3, which is reported to deplete and block the function of Kupffer cells, 24 h prior to tumor cell inoculation resulted in a 5-fold tumor mass increase relative to control. Injection of anti-asiolo-GM1 antiserum, which eliminates the hepatic NK-cells, induced a 10-fold increase in tumor mass. These results indicate an important early antimetastatic function of hepatic NK-cells and KC and that presurgical administration of IFN-gamma may be important for eliminating circulating tumor cells and inhibiting development of residual tumors.

Kupffer cells and liver metastasis. Optimization and limitation of activation of tumoricidal activity

Kupffer cells, tissue-fixed macrophages located in the sinusoids of the liver, represent the highest concentration of mononuclear phagocytes in the body. Their ability to act as scavengers of particulate material in the blood has given rise to speculation that they play a role in controlling hepatic metastases derived from blood-borne tumor cells. Circumstantial evidence for such a role has been obtained from animal studies where Kupffer cell function has been compromised or inhibited, and from anecdotal clinical observations. Current evidence suggests that Kupffer cells are capable of nonspecifically eliminating some circulating tumor cells from the circulation via phagocytosis. This surveillance mechanism would appear to be limited in capacity, and subject to a number of external factors. Recent studies have demonstrated that Kupffer cells can be activated to a tumoricidal state via the administration of biological response modifiers such as gamma interferon or muramyl peptides. The localization of liposomes within Kupffer cells after systemic administration has provided a considerable stimulus for the efficient targeting of macrophage-activating compounds to these cells. Such therapeutic intervention, while capable of inducing Kupffer cell tumoricidal activity in situ and inhibiting tumor growth, is limited with respect to the location of the tumor cells (sinusoidal versus parenchymal) and to the size of the metastatic nodule. Therapeutic intervention using liposomes containing macrophage-activating agents may only be of benefit in patients with minimal tumor load who are at risk for hepatic metastases, rather than those patients who already have clinically detectable liver tumors.

Failure of orally administered RA233 to influence B16 melanoma growth or metastasis

Possible prophylactic antitumor and/or antimetastatic effects of long-term oral administration of a potent inhibitor of platelet aggregation, the pyrimido-pyrimidine derivative RA233, were assessed using four phenotypically distinct clones of the mouse B16 melanoma. The clones tested included: a poorly tumorigenic, very slowly growing and poorly metastatic population (G3.15); a moderately tumorigenic and slowly growing population that frequently metastasizes to the lungs (G3.5); a highly tumorigenic, moderately growing and highly metastatic population (G3.12); and a highly tumorigenic and rapidly growing population that is generally nonmetastatic but can be slightly metastatic when tumors are initiated by very small numbers of cells (G3.26). Addition of 0.5 mg/ml RA233 to the drinking water continuously from the time of subcutaneous injection of cultured tumor cells until death from tumor growth, which resulted in a daily uptake of 80-100 mg/kg of drug per mouse, failed to significantly influence the tumorigenicities, tumor growth rates, metastatic incidences, or metastatic burdens of any of these clones. RA233 at doses equivalent to those delivered daily to experimental animals strongly inhibited ADP-induced aggregation of homologous C57BL/6 mouse platelets and exhibited selective anti-proliferative effects on cultured cells. Although RA233 prolonged bleeding times, pharmacokinetic analysis indicated that clearance of RA233 from mice was so rapid that achievement of sustained circulating levels sufficient to influence tumor cells or platelet-tumor cell interactions by oral administration was unlikely.

Neoadjuvant (preoperative) chemotherapy for breast cancer

Despite recent developments in the treatment of breast cancer, metastatic breast cancer remains an incurable disease. Postoperative adjuvant treatment may improve the survival of a subgroup of node positive, Stage II breast cancer patients, but the proportion of failures is still high. Preoperative adjuvant chemotherapy, an example of a new approach in scheduling of available agents, is based on sound theoretical and experimental principles. In this report, the authors summarize the background data on the rationale for preoperative adjuvant chemotherapy and present preliminary results of this study in which preoperative treatment starting with one course of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) was given to newly diagnosed patients with breast cancer. Analysis of the first 43 patients given such treatment has shown that the side effects were comparable to those seen in patients treated with conventional postoperative chemotherapy, and that the delay time between diagnosis and starting chemotherapy has been substantially reduced compared to the historic group of patients. Additional aspects of this study include the introduction of fine-needle aspiration as the only diagnostic method for obtaining the tissue diagnosis of breast cancer, as well as a more intensive interaction between the surgeons from private practice and the oncology institute.

Effect of plasma fibronectin, macrophages, and glycosaminoglycans on tumor cell growth

Fibronectin (Fn) synergizes with macrophages (M phi) in inducing cytostasis and cytotoxicity of neoplastic cells in culture. Since heparin enhances Fn's opsonic activity in many systems, we investigated its effect on Fn-macrophage synergy in cytostasis. MCG-T14 (a spontaneous mouse mammary adenocarcinoma) cells (4 X 10(4] were added to wells both with and without C. parvum activated M phi monolayers. To these cultures were added increasing concentrations of Fn with or without heparin. Fn synergizes with both M phi S and heparin in inhibiting tumor cell growth. The combined cytostatic effect of Fn, heparin and M phi S is more than additive. In other experiments, MCG-T14 cells were pre-incubated for 2 hr with Fn, washed free of Fn, and treated as above. The results of these experiments were similar to coculture experiments, but the effect of heparin was even more pronounced. Dermatan sulfate and hyaluronic acid had a variable effect on Fn and Fn-macrophage induced cytostasis.

Effect of operation on peripheral lymphocyte counts and production of adenosine triphosphate (ATP) in cancer patients

Lymphocyte bioenergetics in cancer patients undergoing surgery is largely unexplored. The effect of surgery on total lymphocyte counts and adenosine triphosphate (ATP) production is reported. Lymphocyte ATP was assayed by the coupled enzymatic method using hexokinase and glucose 6-phosphate dehydrogenase and lymphocyte counts were calculated from total leukocyte counts and differential counts. Lymphocyte ATP assay and counts were carried out in 13 patients pre- and postoperatively, and lymphocyte counts were scored in six more patients similarly. In 69% of the patients lymphocyte ATP production was depressed postoperatively, and this condition appeared to be associated with cancer spread and immunosuppressive tumors. Postoperative increase in lymphocyte ATP was observed following hysterectomy, colostomy, and also after blood transfusion. The significance of the findings are discussed. Changes in postoperative lymphocyte counts correlated with lymphocyte ATP in 62% of the cases.

Prevention of liver reticuloendothelial systemic host defense failure after surgery by intravenous opsonic glycoprotein therapy

Depression of the reticuloendothelial system (RES) was observed in rats following operative trauma consisting of laparotomy and jejunal enterotomy. This RES depression was manifested as a significant impairment in the phagocytic clearance of intravenously injected blood-borne test colloid mediated by a decline in hepatic Kupffer cell phagocytosis. Reticuloendothelial systemic host defense depression was correlated with a significant decline in bioassayable and immunoreactive opsonic alpha(2)SB glycoprotein concentration over a 1-3 hr postoperative period with rebound elevation in opsonic activity by 24 hr postsurgery. Intravenous administration of purified opsonic alpha(2)SB glycoprotein at the end of the operation prevented postoperative opsonic deficiency and restored normal hepatic RES phagocytic function. These studies coupled with previous observations in patients following surgery or after severe multiple trauma suggest that reticuloendothelial depression during and after operation mediated by opsonic deficiency may lead to a precarious imbalance between systemic host defense and the dissemination of blood-borne foreign and effete particulate matter such as injured platelets, fibrin microaggregates and immune complexes. Immunoreactive serum opsonic alpha(2)SB glycoprotein determinations may serve as a valuable index of hepatic RE clearance capacity and opsonin therapy may potentially be a selective means to augment systemic host defense.

Heparin, dextran 1000 and metastasis formation after I.V. tumour cell injection in dextran non-sensitive rats

The present study of the effect of heparin and dextran 1000 on the metastasis formation after i.v. tumour cell injection in dextran non-sensitive rats using a syngeneic 20-methylcholanthrene induced fibrosarcoma showed that heparin treatment decreased with formation of pulmonary metastases in animals both untreated and treated with dextran 1000. Treatment with dextran 1000 increased the formation of pulmonary metastases in animals both untreated and treated with heparin and the effect of dextran 1000 was thus not affected by heparin treatment. Heparin did not have any direct action on the tumour cells, which influenced metastasis formation. The data suggest that heparin acts as an anticoagulant with decreased microthrombus formation around lodged cells and that dextrax 1000 stimulates metastasis formation primarily by mechanisms other than intravascular coagulation.