Suppression of tumor growth by peritoneal macrophages isolated from mice treated with carboxyethylgermanium sesquioxide (Ge-132)

In a murine model it has been shown that the antitumor activity of carboxyethylgermanium sesquioxide (Ge-132) can be depleted by administration of macrophage (M phi) blockers. In the present study, the role that M phi play in the antitumor activity of the compound was investigated. Oral administration of Ge-132 in mice was demonstrated to be effective in activating M phi (Ge-132-cytotoxic M phi), and the cytotoxic activity of these M phi appeared in the peritoneal cavity of mice 48 hours after the oral administration of the compound. Co-cultivation of RL male-1 leukemia or Ehrlich carcinoma cells with Ge-132-cytotoxic M phi in vitro resulted in marked suppression of the growth of tumor cells. The transfer of peritoneal exudate cells (PEC), or purified M phi fractions of PEC from Ge-132-treated mice to mice bearing Ehrlich or RL male-1 ascites tumors resulted in significant protection. However, when the cytotoxic M phi were depleted by carbonyl-iron treatment in vitro, no antitumor effect was demonstrated in mice bearing Ehrlich or RL male-1 ascites tumors. Macrophage fractions obtained from PEC of Ge-132-treated mice exhibited an inhibitory effect against certain tumors both in vivo and in vitro suggesting that the antitumor effect of Ge-132 observed in vivo resulted from the activation of M phi.     

Importance of T-cells and macrophages in the antitumor activity of carboxyethylgermanium sesquioxide (Ge-132)

The purpose of this study was to investigate the effective mechanisms of Ge-132, an organogermanium compound with immunomodulatory activity, on experimental murine ascites tumors. The antitumor effects of Ge-132 were observed when mice inoculated with Ehrlich carcinoma (allogeneic) or RL male 1 leukemia (syngeneic) cells were treated orally. However, Ge-132 had no activity on EL-4 lymphoma (syngeneic) or Meth A fibrosarcoma (syngeneic). The antitumor activity of Ge-132 was not observed when tumor-bearing mice were treated with trypan blue, carrageenan, or monoclonal anti-Thy 1.2 antibody. However, when natural killer (NK) cells were eliminated from mice bearing RL male 1 or Ehrlich ascites tumors by treatment with anti-asialo GM1 antiserum, the antitumor activity of the compound was unchanged. This suggests that Ge-132 was effective against certain ascites tumors regardless of whether the tumor was syngeneic or allogeneic. Furthermore, its effect might be expressed through host defense mechanisms, including macrophages and/or T-cells.     

Cooperation of lymphokine(s) and macrophages in expression of antitumor activity of carboxyethylgermanium sesquioxide (Ge-132)

The administration of IFN containing sera (Ge-sera) obtained from Ge-132-treated mice (Ge-mice) or the passive transfer of macrophages (M phi) to mice bearing ascites tumors resulted in the inhibition of tumor growth. The cooperative role of Ge-sera and Ge-M phi in the display of Ge-132-antitumor activity was studied. When mice were pretreated with antimouse IFN gamma antiserum, no IFN-inducing and antitumor activities of the compound were detected. Cytotoxic activities were detected on peritoneal M phi of mice treated with Ge-sera, and passive transfer of these M phi to tumor-bearing mice resulted in the inhibition of tumor growth. When tumor-bearing mice were pretreated with substances toxic to M phi, there was no antitumor activity of Ge-sera observed. However, there was antitumor activity of Ge-sera in mice depleted of T-cells, even though the antitumor effects of the compound itself were not demonstrable in T-cell depleted mice. Therefore, a part of the antitumor activity of Ge-132 may appear to be expressed as follows: (1) Ge-132 stimulated T-cells to produce circulating lymphokine(s) which were inactivated by anti-IFN gamma treatment; (2) activated M phi were generated from resting M phi by such lymphokine(s); (3) the transplanted tumors were inhibited by these M phi.     

Antitumor effect in mice of an organic germanium compound (Ge-132) when different administration methods are used

The antitumor effect of an organic germanium compound, carboxyethylgermanium sesquioxide (Ge-132), was examined in mice using two systems: one, the ascitic form of Ehrlich carcinoma in DDI mice, and the other, the solid form of Meth-A fibrosarcoma in BALB/c mice. In the mice with Ehrlich ascitic tumors, a remarkable prolongation in life span was observed after intraperitoneal (i.p.) or per oral (p.o.) administration of Ge-132 (300 mg/kg), but not after intravenous (i.v.) injection of the same compound. Following i.p. or p.o. administration, cytotoxic macrophages (M?) were induced in the peritoneal cavity after 48 h. although this was not the case after i.v. injections. When the in vivo effect of these in vitro active M? was examined after adoptive transfer to mice bearing Ehrlich ascitic tumor cells, a significant antitumor effect was noted. In the mice bearing solid Meth-A tumors, i.v. injections of Ge-132 (100 mg/kg) were found to inhibit tumor growth remarkably, although i.p. and p.o. administrations did not have the same result. This inhibitory effect of Ge-132 by i.v. administration was explained by the continued augmentation of NK activity in peripheral blood, which was followed by the induction of specific killer cells appearing in the spleen. When the mice which had recovered from Meth-A tumor growth, following i.v. injections of Ge-132, were challenged with the same tumor on day 30, all mice were able to tolerate the challenge, but not a challenge of RL male 1 tumor cells. These observations may indicate that the differing antitumor effects of Ge-132 produced when different administration methods are used can be explained by the variation in effector cells induced by such different administration routes.     

Ability of sera from mice treated with Ge-132, an organo-germanium compound, to inhibit experimental murine ascites tumors

Serum specimens from mice treated orally with Ge-132 (100 mg/kg) exhibited antitumor activity against Ehrlich (allogeneic) and RL 1 (syngeneic) ascites tumors in BALB/c mice. Sera obtained from mice 24 hours after Ge-132 administration displayed the highest antitumor effect and the antitumor activity was dose-dependent. Sera prepared from mice 12, 36 or 48 hours after Ge-132 treatment had no protective effect. Circulating interferon (IFN) was induced at 24 hours after administration. The antiviral activity of serum from Ge-132-treated mice was inactivated by treatment with trypsin, low pH, and anti-IFN-gamma antiserum. The inactivated preparations of serum IFN induced by Ge-132 did not show antitumor activity when administered to mice bearing Ehrlich ascites tumors. These results suggest that the antitumor activity in the sera of Ge-132-treated mice may have been expressed through IFN-gamma which was induced by Ge-132.     

Suppression of Ehrlich ascites tumors in mice by minute virus of mice

As a model system to study parvoviral oncosuppression, Ehrlich ascites (EA) cells were injected into the peritoneal cavities of ICR mice, and the effect of im injection of minute virus of mice (MVM) on EA tumor growth was examined. Coinjection with MVM resulted in a dramatic inhibition of EA tumor formation. Tumor suppression required viable, infectious virus. Mice that had survived one EA-MVM coinjection acquired long-term resistance to additional injections of EA cells.     

Changes in lipoprotein lipase activity (LPLA) in tumor cells and tissues in mice bearing Ehrlich ascites tumor

Lipid content and lipoprotein lipase activity (LPLA) of serum and various tissues of mice bearing Ehrlich ascites tumor have been studied. The growing tumor caused hyperlipidemia, depletion of adipose tissue, a slight increase of heart lipid content, lipid accretion in the tumor cells and a relative increase of free fatty acids and cholesterol in the ascites fluid. LPLA of the post-heparin plasma was higher in tumorous than in control mice. Tumor growth led to a marked decline of LPLA in the adipose tissue and an elevation in the heart. It declined slightly in the older tumor cells and increased in the ascites plasma of the same. It has been concluded that: a) decline in adipose tissue LPLA may play an important part in the development of hyperlipidemia and loss of body fat; b) increase of the heart LPLA proves insufficient for elimination of the piled up blood lipids during progression; c) LPLA in the ascites fluid may favour the hydrolysis of triglycerides entering the ascites fluid, which might account at least in part for the fatty acids made available to the tumor; d) LPLA detected in the tumor cells might also facilitate the assimilation of lipids by the tumor cells.     

Increase in alkaline phosphatase activity in the liver of mice bearing Ehrlich ascites tumor.

In mice bearing Ehrilich ascites tumors, alkaline phosphatase activity was increased fivefold in the liver and by 50% in the kidney. In mice bearing solid tumors caused by inoculation of tumor cells into the axillary region, the activity of this enzyme in the liver was increased 11-fold, whereas the activity in the kidney did not change. Alkaline phosphatase activities in the liver and kidney were not altered by administration of adrenal steroids. Adrenalectomy, fasting, and pregnancy did not affect the activity of alkaline phosphatase in the liver and kidney. Treatment with tumor extracts or ascites fluid of normal mice increased liver alkaline phosphatase activity. These findings suggested that the elevation of liver alkaline phosphatase activity was cuased primarily by the tumor itself, and not by hormonal imbalance provoked secondarily by the presence of the tumor.     

Folate enzymes in Ehrlich ascites carcinoma-bearing mice

The activity of 4 enzymes involved in the formation and interconversion of folate coenzymes has been examined in liver and kidney of healthy and Ehrlich ascites carcinoma-bearing mice. In the liver, a 50% increase of methylenetetrahydrofolate reductase activity was shown soon after tumour cell inoculation, while the activity of formyltetrahydrofolate synthetase and methylenetetrahydrofolate dehydrogenase decrease by 20% at an advanced stage of tumour development. In kidneys of the host mouse the only change observed was a decrease of dihydrofolate reductase activity. The levels of activity of all assayed enzymes found in host organs were similar to that in Ehrlich carcinoma cells.     

羧乙基锗倍半氧化物抗移植瘤实验

将移植了ＨｅｐＡ鼠肝癌的ＮＩＨ鼠随机分为四组，一组作对照组，另三组分别给予Ｇｅ－１３２、ＣＹ、Ｇｅ－１３２＋ＣＹ治疗。２周后处死，测定血清中ＳＯＤ活性，对瘤体进行病理切片检查。结果表明：治疗组肿瘤重量较轻，ＳＯＤ活性较高（Ｐ＜０．０５）。Ｇｅ－１３２组的癌组织中白细胞浸润程度较高，细胞免疫力较强。对鼠肝癌的抑制率，Ｇｅ－１３２与ＣＹ合用有相加作用。     

Antitumor effect of normal intestinal microflora on Ehrlich ascites tumor

In order to investigate the antitumor activity of intestinal microflora, the constitution of normal flora was examined in humans, guinea pigs and mice. It was clarified that Eubacterium, Bifidobacterium and Bacteroides were the predominant bacterial genera in humans. In addition, neither Clostridium nor Enterobacteriaceae was detected in guinea pigs and neither Clostridium nor Bifidobacterium was present in mice. Total bacterial counts in tumor-bearing mice were reduced in comparison with those in normal mice. Especially, in the ileum of tumor-bearing mice, the incidence of anaerobic bacterial genera was strikingly decreased. From the bacteria found, 59 living and killed strains isolated from intestinal microflora were examined for antitumor activity against Ehrlich ascites tumor. It was observed that 11 of the tested strains had antitumor activity. Four of these were toxic to the host, and in particular, all mice injected with Pseudomonas aeruginosa (TYM-8) died within several days. Eubacterium lentum (TYH-11), Propionibacterium acnes (TYM-28), Proteus mirabilis (TYM-7) and Serratia marcescens (TY-142), in which antitumor activity was recognized with living and formalin-killed bacteria, cured the tumor-bearing mice, and the culture supernatant of S. marcescens contained apparent antitumor activity.