Roles of selenium in endotoxin-induced lipid peroxidation in the rats liver and in nitric oxide production in J774A.1 cells.

We examined the role of selenium (Se) in the mechanism of oxidative stress caused by endotoxin by feeding rats deficient a diet in this element. In rats fed the Se-deficient diet (concentration of Se, less than 0.027 microg g(-1)) for 10 weeks, Se level and glutathione peroxidase (GSH-Px) activity in the liver were about 47 and 43% lower, respectively, than those in rats fed a Se-adequate diet (Se, 0.2 microg g(-1)). Rat fed the Se-deficient diet and given endotoxin (6 mg kg(-1), i.p.) showed a mortality rates of about 43% at 18 h. Nevertheless, no lethality was observed with endotoxin (4 mg kg(-1), i.p.) challenge. Levels of serum lactate dehydrogenase and acid phosphatase leakage were significantly higher in Se-deficient rats than those in Se-adequate diet 18 h after endotoxin (4 mg kg(-1), i. p.) challenge. Superoxide anion generation and lipid peroxide formation in the liver of Se-deficient rat were markedly increased 18 h after endotoxin (4 mg kg(-1), i.p.) injection compared with those in the endotoxin/Se-adequate diet group, whereas non-protein sulfhydryl level in the liver after administration of endotoxin to Se-deficient rats was lower than that in Se-adequate rats treated with endotoxin. We investigated whether Se can suppress nitric oxide (NO) generation and cytotoxicity in endotoxin-treated J774A.1 cells. Treatment with Se (10(-6) M) markedly inhibited endotoxin (0.1 microg ml(-1))-induced NO production in J774A.1 cells. Se induced an increased activity of GSH-Px in cells after 24 h of incubation, suggesting that the preventive effect of Se on NO production in endotoxemia is due to the induction of Se-GSH-Px activity. However, Se did not affect endotoxin-induced cytotoxicity in J774A.1 cells. These findings suggested that the oxidative stress caused by endotoxin may be due, at least in part, to changes in Se regulation during endotoxemia.

Effects of antitumor activity and protection of shock symptoms by a traditional Chinese medicine (sho-saiko-to) in recombinant human tumor necrosis factor administered mice.

The effects of a traditional Chinese medicine Sho-saiko-to (Kampo prescription) were investigated on the various metabolic disorders and antitumor activity of recombinant human tumor necrosis factor (rhTNF) administered to mice. The glycogen level in liver of rhTNF (5 x 10(4) units/mouse, i.v.)-injected mice was markedly lower at 4 h post-intoxication than that in the control, whereas the administration of rhTNF to Sho-saiko-to (500 mg/kg/d, p.o.)-pretreated mice resulted in a greater level of glycogen than that in rhTNF alone-treated mice. In mice pretreated with Sho-saiko-to, the level of fibrinogen 4 h after rhTNF injection markedly increased as compared to that in mice treated with rhTNF alone. We also estimated the NO2 in murine macrophage cell line J774A.1 using mice serum after administration of Sho-saiko-to. Our results clearly demonstrated that J774A.1 cells stimulated with endotoxin (1 micrograms/ml) and rhTNF (1 x 10(4) units/ml) can effectively produce nitric oxide (NO), and ascertained the suppressive effect of Sho-saiko-to (500 mg/kg/d, p.o)-pretreated serum on NO generation by endotoxin/TNF-activated J774A.1 cells. When the cells were incubated with endotoxin/TNF and Sho-saiko-to pretreated serum (10-100 microliters), the NO level was significantly lower than that in control serum incubated with endotoxin/TNF alone. The effect of Sho-saiko-to (1 and 10 micrograms/ml) on in vitro cytotoxicity by rhTNF in Meth-A Sarcoma cells was observed to be in a dose dependent fashion. In addition, there was a remarkable enhancement of antitumor activity of rhTNF by Sho-saiko-to pretreatment in mice. These findings suggest that the Kampo prescription Sho-saiko-to may protect mice from severe shock syndrome by rhTNF, and that it may enhance rhTNF-induced activity.

Depressive effect of a traditional Chinese medicine (sho-saiko-to) on endotoxin-induced nitric oxide formation in activated murine macrophage J774A.1 cells.

The present study investigated whether or not Sho-saiko-to (crude powder extract, TJ-9) can suppress nitric oxide (NO) generation by endotoxin-activated J774A.1 cells in order to study the preventive mechanism of Sho-saiko-to against endotoxemia. In this experiment, we estimated the NO2- in the murine macrophage cell line J774A.1 using the Griess method. Our results clearly demonstrated that J774A.1 cells stimulated with endotoxin (0.01-10 micrograms/ml) can effectively produce NO, and the production was dependent on the dose of endotoxin. On the other hand, we investigated the suppressive effect of TJ-9 (10-100 micrograms/ml) on NO generation by endotoxin (0.1 microgram/ml)-activated J774A.1 cells. The NO level when the cells were incubated with endotoxin and TJ-9 (10-20 micrograms/ml) was slightly lower than that in cells treated with endotoxin alone. In contrast, treatment with TJ-9 (50-100 micrograms/ml) significantly inhibited endotoxin-activated NO generation in J774A.1 cells, whereas the treatment with TJ-9 (10-100 micrograms/ml) alone was ineffective in inducing NO formation and in inhibiting cell viability in the J774A.1 cells. These findings suggest that a Kampo presciption of Sho-saiko-to shows a suppressive effect on NO generation in macrophages stimulated with endotoxin, and that it may be useful in improving endotoxin-shock symptoms.

Antileukemic activity of Viva-Natural, a dietary seaweed extract, on Rauscher murine leukemia in comparison with anti-HIV agents, azidothymidine, dextran sulfate and pentosan polysulfate.

An antileukemic activity of partially purified polysaccharide of an edible seaweed. Viva-Natural, against Rauscher murine retrovirus-induced erythroleukemia has been demonstrated. This antileukemic effect is compared with standard anti-human immunodeficiency virus (HIV) agents, azidothymidine (AZT), dextran sulfate and pentosan polysulfate. Pretreatment with Viva-Natural, as an immunomodulator, on day 3 prior to the virus inoculation demonstrated definite prophylactic activity, while pretreatment with the other three anti-HIV agents showed no prophylactic activity. The replication of Rauscher virus in BALB/3T3 cell cultures accompanied by direct cytopathic effect (syncytia formation) was suppressed in the presence of Viva-Natural or the other anti-HIV agents in the culture medium. In spite of the antiviral potentials of the four agents in vitro, only Viva-Natural and AZT demonstrated therapeutic efficacy against Rauscher leukemia in mice.

Preventive effects of a Chinese herb medicine (sho-saiko-to) against lethality after recombinant human tumor necrosis factor administration in mice.

We observed the effects of a chinese herb medicine Sho-saiko-to on the lethal and antitumor activities of recombinant human tumor necrosis factor (rhTNF) administered in mice. Sho-saiko-to was noted to protect the rhTNF-induced lethality in galactosamine-hypersensitized mice, and also Sho-saiko-to pretreated mice was protected against the decrease of rectal temperature after rhTNF administration. On the other hand, there was a remarkable enhancement of antitumor activity of rhTNF by Sho-saiko-to pretreatment. These results suggest that Sho-saiko-to drug may protect mice from severe shock syndrome induced by rhTNF.

Potentiation of antitumor activity of pirarubicin by chlorpromazine in mice bearing doxorubicin-resistant P388 leukemia.

Chlorpromazine enhanced the cytotoxicity of pirarubicin against doxorubicin-resistant P388 leukemia cells in colony forming assays. Chlorpromazine also prolonged the survival of mice bearing doxorubicin-resistant P388 leukemia, when given in combination with pirarubicin.

Anticancer potential of Viva-Natural, a dietary seaweed extract, on Lewis lung carcinoma in comparison with chemical immunomodulators and on cyclosporine-accelerated AKR leukemia.

Viva-Natural, extracted from a dietary seaweed, containing a macrophage-activating polysaccharide, has been confirmed to be active against intraperitoneally implanted Lewis lung carcinoma (LLC) and spontaneous AKR T cell leukemia. The antitumor potential against LLC has been evaluated in comparison with standard synthetic immunomodulators such as pyran copolymer (MVE-2), isoprinosine, levamisole, and tilorone while manipulating the immune systems by immunosuppressive agents, cyclophosphamide (CY) and 2-chloroadenosine. The anti-LLC activity of Viva-Natural has been found to be superior to that of isoprinosine but inferior to that of MVE-2. LLC-enhancing effect of CY could be partially reserved by the subsequent administration of Viva-Natural or MVE-2 but not by isoprinosine. 2-Chloroadenosine, a specific macrophage inhibitor, abrogated the anti-LLC activity of Viva-Natural and isoprinosine but not the activity of MVE-2. Levamisole and tilorone showed no anti-LLC activity. Ethanol-precipitable fraction of water-soluble part of Viva-Natural (crude polysaccharide) demonstrated curative activity similar to that of MVE-2. Viva-Natural reversed the potentiation effect of ciclosporin on the development of leukemia in AKR mice at preleukemic stage.

Effect of pretazettine and viva-natural, a dietary seaweed extract, on spontaneous AKR leukemia in comparison with standard drugs.

Antileukemic activity of pretazettine hydrochloride (PTZ: a narcissus alkaloid) and Viva-Natural (a seaweed extract) has been confirmed against spontaneous AKR T cell leukemia in mice containing 20% of advanced leukemia. The activity of both agents has been compared with selected standard cytotoxic drugs, vincristine (VCR), methotrexate (MTX), 6-thioguanine (6-TG), and adriamycin (ADR), and immunomodulators, pyran copolymer (MVE-2), isoprinosine, levamisole and tilorone. PTZ activity seems to be superior (90% increase in life span, ILS) to those of MTX (71% ILS), 6-TG (60%), and ADR (49%), and inferior to VCR (114% ILS). Viva-Natural has been found to be the only immunomodulator (61%) active against AKR T cell leukemia, while all standard immunomodulators tested were not active. Combination treatment of PTZ with VCR, or 6-TG, or ADR, or Viva-Natural were synergistic, but combination of PTZ with MTX was not beneficial. PTZ or VCR has been found to be therapeutically very effective (323 or 347% ILS, respectively) against mice in advanced stage of leukemia, and induced complete clinical remissions. Also, PTZ has been found to reverse the leukemia-enhancing effect of ciclosporin in AKR mice at preleukemic stage.

Evaluation of antitumor activity of 1-beta-D-arabinofuranosyl-2-amino-1,4(2H)-4-iminopyrimidine in murine tumors.

1-beta-D-Arabinofuranosyl-2-amino-1,4(2H)-4-iminopyrimidine (ara-AIPy), a new deaminase-resistant analog of cytarabine, exhibited extremely potent antitumor activity against P388 leukemia [400 mg/kg on Days 1-5; increase in life span (ILS), 211%] and significant inhibition against Lewis lung carcinoma (inhibition of tumor weight, 68%) and mammary adenocarcinoma 755 (inhibition of tumor weight, 82%). Schedule-dependency studies indicate that this drug, unlike cytarabine, was effective irrespective of its treatment schedules. The drug exhibited therapeutic efficacy against established P388 tumor transplants (400 mg/kg on Days 3-7; ILS, 131%) and inhibited the tumor growth effectively even when administered as a single dose on Day 1 by both ip (2000 mg/kg; ILS, 150%) and iv (500 mg/kg; ILS, 68%) routes. Ara-AIPy was most effective when administered on Days 1, 3, 5, 7, and 9 after tumor transplantation (400 mg/kg; ILS, 210%, with 50% of animals 60-day survivors). Ara-AIPy inhibited the growth of L1210 leukemia when both the tumor transplantation and the drug treatment were administered by iv route (500 mg/kg on Days 1, 5, and 9; ILS, 181%). The routes of administration of ara-AIPy experiments showed that the drug was effective by both ip and iv routes of administration; however, better therapeutic values were obtained by ip schedules. These studies demonstrate that ara-AIPy exhibits highly significant and broad-spectrum antitumor activity against a variety of experimental animal tumor models and suggest a possible future role for this drug in the treatment of human neoplasia.

Antitumor activity and mechanism of action of 6-thio-3-deazaguanine.

6-Thio-3-deazaguanine (TDG), a relatively new purine antimetabolite, exhibits significant antitumor activity against a variety of experimental animal tumor models including C3H mammary adenocarcinoma, Lewis lung carcinoma, adenocarcinoma 755, and leukemias L1210 and P388. However, the drug was ineffective against 3-deazaguanine-resistant L1210 (both in vitro and in vivo) and CEM cells (in vitro). The resistant cells appear to lack HGPRTase activity because the extracts from these cell lines failed to convert hypoxanthine to IMP. These data indicate that TDG needs to be activated by hypoxanthine guanine phosphoribosyltransferase prior to its growth inhibitory effects. Cytotoxicity of TDG was completely reversed by hypoxanthine and inosine. TDG inhibited the synthesis of DNA and RNA equally and effectively, whereas the inhibition of protein synthesis required a prolonged drug exposure and appears to be a consequence of the inhibition of DNA and RNA synthesis. Data from these studies suggest that TDG is an effective antitumor agent, and its spectrum of antitumor activity and mechanism of action appears to be different from that of 3-deazaguanine.

Anticancer activity of a natural product, viva-natural, extracted from Undaria pinnantifida on intraperitoneally implanted Lewis lung carcinoma.

A natural product, named Viva-Natural, extracted from a dietary seaweed Undaria pinnantifida has been found to be therapeutically active against Lewis lung carcinoma (LLC). Viva-Natural also demonstrated moderate prophylactic activity against LLC in allogeneic mice. The active principle(s) which was concentrated in the water-insoluble fraction of Viva-Natural was essentially noncytotoxic in KB cell cultures, and probably a polysaccharide. Viva-Natural was found to be significantly effective in enhancing the natural cytolytic activity of peritoneal macrophages against KB cells as targets in in vitro assay, suggesting that the antitumor action of Viva-Natural might be indirect through the activation of nonspecific immune systems. A combination therapy of Viva-Natural and standard anticancer drugs was additively or synergistically effective.

Therapeutic activity of pretazettine, a narcissus alkaloid, on spontaneous AKR leukemia.

A narcissus alkaloid, pretazettine hydrochloride (PTZ) has been shown to be active against spontaneous AKR leukemia. The long-term treatment with PTZ begining at 5--7 months of age of a group of AKR mice containing 10--20% of advanced leukemic mice significantly prolonged the life span of the group. The therapeutic effectiveness of PTZ has been compared with several standard antileukemic drugs. PTZ decreased the AKR virus titer in the circulating blood of mice and its antiviral activity in AKR virus infected NIH/3T3 cells has been confirmed by XC assay.

Therapeutic activity of pretazettine on Rauscher leukemia: combination of antiviral activity and cellular protein inhibition.

Pretazettine hydrochloride (PTZ) has been found to inhibit protein synthesis, without being inhibitory to DNA and RNA, in Rauscher leukemic blood cells in mice for at least 6 h after its administration. With comparison to Virazole and cycloheximide, the specific anti-Rauscher virus activity of PTZ has been demonstrated only in acutely-infected NIH/3T3 cells but not in chronically-infected cells. It is not certain that the inhibitory action of PTZ on reverse transcriptase is contributory to its therapeutic activity in leukemic mice.

Therapeutic activity of pretazettine, a narcissus alkaloid on Rauscher leukemia: comparison with tazettine and streptonigrin.

The therapeutic activity of narcissus alkaloid pretazettine HC1 (PTZ) on established Rauscher leukemia has been demonstrated and compared with the isomer tazettine (TZ) and an antibiotic, streptonigrin (SN). PTZ and SN showed remarkable prolongation effect on the life span of the leukemic mice and the antiviral activity has been confirmed in mouse 3T3 cells infected with Rauscher virus. TZ showed no significant activity in the leukemic mice and was inhibitory to the virus growth in the cells at much higher doses than PTZ. It is suggested that the stereochemical rearrangement from PTZ to TZ inactivates the biological activity of PTZ.

Combination chemotherapy of Rauscher leukemia and ascites tumors by narcissus alkaloid with standard drugs and effect on cellular immunity.

The therapeutic activity of the narcissus residual alkaloid A-2 against Rauscher leukemia has been compared with 10 standard anticancer drugs, and synergistic or additive combination pairs have been selected using a viral leukemia and two transplantable tumor systems. An increased beneficial effect has been demonstrated by a combination of the alkylating and DNA-binding agents and the alkaloid against the three malignant tumors, while a beneficial effect by combining the alkaloid and the antimetabolites (either 6-MP or 5-azacytidine) was seen only against the viral leukemia. The alkaloid has no suppressive activity against cellular immunity as tested by PHA reactivity and allogeneic tumor rejection systems.