Enhancement of interferon antitumor action by sodium butyrate.

Sodium butyrate together with interferon enhances the antitumor effect of interferon in vivo. When Sarcoma 180 TG cells are inoculated in mice, the mean survival time and final survival rate are greatly increased compared to those for treatment with interferon alone. Similarly, a significant delay in the mean survival time is observed when mice inoculated with L1210 cells are treated with sodium butyrate and interferon. This effect could be due at least in part to a potentiation of interferon action on the tumor cells.

Testicular wild-type p53 expression in transgenic mice induces spermiogenesis alterations ranging from differentiation defects to apoptosis.

While p53 is dispensable for development, an excess of p53 has dramatic consequences on the embryogenesis and on the cell differentiation. In an attempt to analyse in vivo the effects of p53 activity, we have generated transgenic mice expressing the wild-type p53 under the control of the metallothionein I promoter. In the three transgenic lines established, exogenous p53 is expressed constitutively in the postmeiotic cells of transgenic males and two lines are subfertile. Transgenic males expressing the upper level of p53 produce few spermatozoa since the majority of developing spermatids undergo apoptosis. In the subfertile males exhibiting an intermediate amount of p53, teratozoospermia is obvious suggesting an altered terminal differentiation of postmeiotic cells. In contrast lower level of p53 does not lead the third line to sterility. These results suggest that the activity of p53 is dependent in vivo on the amount of p53 present within cells, as it has been already demonstrated in vitro.

Randomized trial of CVPP for three versus six cycles in favorable-prognosis and CVPP versus AOPE plus radiotherapy in intermediate-prognosis untreated Hodgkin's disease.

PURPOSE: To evaluate in a randomized trial the impact of three versus six cycles of cyclophosphamide, vinblastine, procarbazine, and prednisone (CVPP) chemotherapy in favorable-prognosis and CVPP versus doxorubicin, vincristine, prednisone, and etoposide (AOPE) plus involved-field radiotherapy (RT) in intermediate-prognosis previously untreated Hodgkin's disease. PATIENTS AND METHODS: Of 256 patients evaluated, 80 with a favorable prognosis according to a prognostic index designed by the Grupo Argentina de Tratamiento de Leucemia Aguda (GATLA) were randomized to three versus six cycles of CVPP without RT and 176 with intermediate risk to CVPP versus AOPE, both for six cycles with RT between the third and fourth cycles of 30 Gy to the involved areas at diagnosis. CVPP consisted of intravenous (I.V.) cyclophosphamide and vinblastine on days 1 and 8, and oral procarbazine and prednisone on days 1 to 14, every 28 days. AOPE consisted of I.V. doxorubicin and vincristine on day 1, oral prednisone on days 1 to 5, and I.V. etoposide on days 1 and 3, every 28 days. RESULTS: Complete remission was obtained in 39 of 41 (95%) patients treated with three cycles of CVPP and 36 of 39 (92%) treated with six cycles in the favorable-risk group (difference not significant [NS]). In the intermediate-risk group, 89 of 92 (97%) treated with CVPP plus RT versus 75 of 84 (89%) treated with AOPE plus RT achieved a complete remission (P = .05). At 60 months, the event-free survival (EFS) and overall survival rates in the favorable-risk group were 80% and 91% for CVPP x 3 and 84% and 97% for CVPP x 6, respectively (P = NS). In the intermediate-risk group, 60-month EFS rate for CVPP plus RT was 85%, compared with 66% for AOPE plus RT (P = .009). The overall survival rate was 95% versus 87% respectively (P = .157). CONCLUSION: Three cycles of CVPP without RT are equally effective as six cycles in the favorable-risk group. However, in the intermediate-group, CVPP plus RT is superior to AOPE plus RT, with significantly fewer events before and after induction (P = .009), without a difference in overall survival.

Results of treatment with an intensive combination induction regimen containing idarubicin in children with acute myeloblastic leukemia: preliminary report of the Argentine Group for Treatment of Acute Leukemia.

In April 1990, the Argentine Group for Treatment of Acute Leukemia began a multicenter trial for the treatment of previously untreated acute myeloblastic leukemia patients who were under 21 years of age. Initial treatment consisted of an 8-day induction phase with cytarabine together with idarubicin on days 3 to 5 and etoposide on days 6 to 8. A multidrug consolidation phase was subsequently administered and, after a treatment-free interval of 2 to 4 weeks, two 5-day intensification courses with high-dose cytarabine and etoposide were delivered with a 4-week interval between each course. Continuation therapy was started 2 to 4 weeks after the second course, with 6-thioguanine daily and cytarabine daily for 4 days every 4 weeks. Treatment was stopped after 18 months in children in continuous complete remission. A preliminary evaluation of this ongoing study included 36 patients with a mean age of 7.5 years (age range, 5 months to 16 years). The majority of patients had a French-American-British classification of M2 (n = 13) or M4 (n = 8). Complete remission was achieved by 91.7% of patients, while one died from sepsis in bone marrow hypoplasia and two were regarded as treatment failures. At a median follow-up of 12 months (range, 2 to 23 months) there were 12 adverse events: six bone marrow relapses, one bone marrow/skin relapse, and five deaths in complete remission (all deaths occurred during the consolidation phase). During the induction phase most of the patients experienced prolonged myelosuppression, and grade 3 to 4 toxicity (according to the Children's Cancer Group criteria) was frequently seen. Alopecia was universal. However, toxicity was manageable. We conclude that idarubicin in combination with cytarabine and etoposide is a highly effective regimen for induction in children with acute myeloblastic leukemia.

Pharmacokinetic study of butyric acid administered in vivo as sodium and arginine butyrate salts.

Considering that butyrate-treated malignant cells can recover in a transitory fashion a non-cancerous phenotype, the authors carried out a pharmacokinetics study of butyric acid injected as sodium or arginine salts for possible antitumor therapies. In the case of 1-14C-labelled butyrate, the appearance of radioactivity in the blood of injected mice is rapid and some of it is maintained for relatively long periods in different organs, mainly the liver. However, no precision can be given about the structure of radioactive compounds in blood and tissues. Using gas-liquid chromatography, the authors studied the metabolism of butyrate in both animals and man. In mice and rabbits, the half-life is less than 5 min. In man, the butyric acid elimination curve can be divided into two parts corresponding to two half-lives: for the first (0.5 min), the slope suggests an accelerated excretion, while for the following (13.7 min), a slow plateau is observed. The rapid elimination of butyrate is a limiting factor for practical applications. However, the lack of toxicity supports its use in human therapy.

Immunomodulatory effects of arginine butyrate.

We have studied the effect of arginine butyrate on T cell and macrophage functions. When target cells are treated with this substance, they become resistant to T cell-mediated cytotoxicity, as detected by the chromium assay. In contrast, when effector T cells are treated, the cytotoxicity seems to be augmented. Peritoneal macrophages incubated with butyrate are increasingly adhesive to substrate. After in vivo treatment, spleen derived macrophages show an augmented cytostatic capacity in the presence of L1210 cells and an enhanced phagocytic activity for IgG-coated erythrocytes. To sum up, the overall effects of butyrate salts on different immune functions are somewhat reminiscent of that of interferon. It is likely that these immune effects contribute, at least in part, to explain its antitumor properties observed in grafted tumors in mice.

Low level toxicity and antitumor activity of butyric mono- and polyester monosaccharide derivates in mice.

This study compares the antitumor activity of five mono- and polyesters of n-butyric acid derived from monosaccharides in the murine model of Crocker 180 TG Sarcoma. Tumor incidence at ten days, mean survival time and final survival rate were significantly affected in all cases. Combined treatment by butyric esters, alpha/beta interferon (IFN) and/or Corynebacterium parvum used as immunestimulator improved the antitumor protection. Studies of acute toxicity in mice, performed by i.p. and oral routes, showed the low toxicity of butyric esters, which were devoid of detectable side effects with no incidence on ponderal growth when administered per os in rats daily for one month. Finally, a comparative study of antitumor activity, toxicity and water-solubility of various butyric esters enabled us to select among these new molecules two isomers (carbon-3 and carbon-6 of the glucose ring substituted with n-butyric acid) derived from monoacetone glucose for further investigations of their biological mechanism in vivo and in vitro.

Pharmacokinetic studies of N-butyric acid mono- and polyesters derived from monosaccharides.

The pharmacokinetics of seven butyric esters derived from monosaccharides were studied after iv administration of a bolus dose to rabbits. Results obtained showed that a constant plasma level of butyric acid is maintained due to the slow disappearance of butyric acid esters from the plasma in contrast to the case of salts, such as arginine butyrate, which are rapidly cleared. The maintenance of these covalent compounds in the body can increase concentrations of n-butyric acid in the tumor area for more efficient chemotherapy. These results seem to be directly related to the in vitro anticellular activity of butyric esters and the prolonged therapeutic protection in tumor-bearing animals.

[Inhibitory effect of arginine butyrate on the development of Crocker 180/TG tumor in Swiss mice]. / Action inhibitrice du butyrate d'arginine sur le développement de la tumeur 180/TG de Crocker chez les souris Swiss.

Arginine butyrate slightly increases the resistance of Swiss Mice to allografted 180/TG tumor cells. A single injection of Corynebacterium Parvum has comparable effects. However, it they are associated, survival rate is significantly augmented.

Antitumor effect of arginine butyrate in conjunction with Corynebacterium parvum and interferon.

The antitumor effect of arginine butyrate, used alone or in conjunction with interferon (IFN), was studied using randomly selected Swiss mice inoculated i.p. with 10(6) 180 TG Crocker tumor cells. The results of these different therapeutic regimens were estimated by tumor incidence at 10 days, by the time necessary to protect 50% of the animals, and by the final survival rate. Combined treatment by IFN and arginine butyrate was effective; but in order to compensate for IFN's immune repressive effects, a single injection of Corynebacterium parvum was administered in some experiments prior to IFN and/or arginine butyrate. After this immune potentiation, both IFN and arginine butyrate used separately significantly protected the animals. However, optimal results were obtained when a single C. parvum injection was followed by nine daily alternating shots of arginine butyrate and IFN.

Aspartate-assisted immune stimulation: its importance in antitumor and antiviral protection.

Immune stimulators such as Corynebacterium parvum (CP) are useful for antitumoral and antiviral therapy. However, the immune trigger cannot be reactivated without adversely affecting the disease. We have tried to amplify the results yielded by a single injection of CP by using either interleukin-2 (IL2) or aspartate salts (ASP). In the present report, we show that IL2 has no detectable clinical effect. In contrast, the addition of an ASP salt increases the antiviral and antitumoral protection afforded by the CP-induced trigger. Moreover, treatment using only ASP slightly protects against tumor development and significantly increases antiviral resistance during experimental encephalomyocarditis (EMC) infection. This ASP-assisted CP immune stimulation improves antitumoral resistance even when ascitic tumors have already developed. In the latter case, tumor regression can even be detected. Since ASP increases T-cell cytotoxicity in vitro and aggravates spontaneous T-cell lymphomas in AKR mice, the involvement of T-cell-mediated immunity may explain antitumoral and antiviral effects. We propose the use of this therapeutic model for human cancer therapy, and possibly for treating AIDS.

Coordinated therapeutic effects of immune modulators and interferon.

Immune modulators injected 24 h before encephalomyocarditis virus significantly increase antiviral resistance in mice when interferon is administered 1 h after the virus. These immune modulators can be crude bacterial extracts or synthetic drugs. In some cases, the responses are additive; in others, they are clearly cooperative. To protect the mice against the development of 180 TG Crocker sarcomas, the association of bacterial extracts and interferon is highly effective under the condition that the drug concentrations and chronological order and number of injections are well defined. In contrast, the conjunction of interferon and synthetic immune modulators, in particular cimetidine, result in delayed tumor development with no significant change in the final survival rate in the experimental model described here.

[Stimulation by isoprinosine of the antiviral effect of interferon]. / Effet stimulant de l'isoprinosine sur l'action antivirale de l'interféron

With a single dose of interferon, isoprinosine greatly enhances the antiviral protection of Mice against the lethal effect of encephalomyocarditis virus (100 LD 50).

Enhancement of antiviral protection against encephalomyocarditis virus by a combination of isoprinosine and interferon.

The antiviral effect of interferon against encephalomyocarditis (EMC) virus infection in mice was enhanced by isoprinosine. However, the enhancement was only obtained when both interferon and the virus were inoculated into the peritoneum; the inoculation route of isoprinosone did not modify significantly the final results. In addition, the time sequence of injections was of great importance; generally the injection of isoprinosine had to precede that of interferon by a few hours.

Antitumor therapy based on the use of an immune modulator, arginine butyrate and interferon.

The analysis of the likely physiological role of interferon during pregnancy and antitumor protection can be employed in developing a new strategy in antitumor therapy. Indeed, pretreatment of the patients with a potent immune stimulation compensates to some extent interferon's immune repressive effects. Through the modulation of the cytoskeleton, interferon enhances macrophage activity. Moreover, butyrate by its own effect on the malignant phenotype increases interferon sensitivity in a number of malignant cells. All of these substances should be used at the lowest possible concentration delivered as closely as possible to the target area.

Importance of coordinated immune stimulation in experimental antitumor treatment.

We have proposed an antitumor therapeutic model in mice grafted with Crocker 180TG cells. The treatment strategy involves a coordinated immune stimulation which should always precede treatment of target cells. Potent stimulators mobilizing the majority of immune competent cells can be injected only once since repetition results in adverse effects on the response. Thus, to circumvent this difficulty, we propose the amplification, after a single shot of Corynebacterium parvum extract, of the immune response by cimetidine. Indeed, it has been reported that cimetidine inhibits suppressor T cell functions. The second phase acting on the target employs interferon and arginine butyrate since they reconvert a number of transformed target cells to normal phenotype. Important antitumor effects can be obtained in the present model even if the treatment is initiated relatively late after tumor graft. All the drugs employed are harmless on normal cells and are used at relatively low concentrations.

Effect of coordinated therapeutic assays using C. parvum, interferon and arginine butyrate on spontaneous disease and survival of AKR mice.

AKR mice, known to develop spontaneous leukemia in almost 100% of cases, were studied throughout their life-span. Different treatments combining a potent immune stimulator, Corynebacterium parvum (CP), with interferon (IFN) and arginine butyrate were initiated at the 15th week of life. In a preliminary series of experiments, CP (200 micrograms), IFN (20,000 units) and butyrate 50 mM) were employed in a well-defined chronological order. In controls, the mean survival time (MST) was 35.17 +/- 1.67 weeks and the final survival rates was 0/50 mice for all experiments. Only CP associated with arginine butyrate significantly augmented the MST (42.5 +/- 3.66 weeks) and final survival rate (9/35 mice). In an adjusted set of experiments, reducing the IFN concentration to 10,000 and 5,000 units and that of butyrate to 6 mM greatly improved the results. The MST was substantially increased with the combinations of CP + IFN + butyrate (41.4 +/- 1.86 weeks), CP + IFN (42.73 +/- 3.29 weeks) and butyrate + IFN (41 +/- 2.34 weeks), as well as the final survival rates (8/15, 10/15 and 6/15 mice respectively). An important finding was that when CP and IFN were used separately, they were ineffective.

Anti-tumor protection induced in mice by fatty acid conjugates: alkyl butyrates and poly(ethylene glycol) dibutyrates.

Simple fatty acids, especially butyrate salts, have interesting biological properties, since they are able to down-regulate cell growth and promote various differentiated cellular functions. Their use for anti-tumor treatment is, however, hampered by their over-rapid diffusion in the blood, followed by a short-lived biological action. We have therefore devised conjugates linking butyrate with either (i) aliphatic alcohols of increasing carbon numbers ranging from C4 to C12 or (ii) poly(ethylene glycols) of increasing molecular weights. In both cases, the resulting butyric esters can be hydrolysed by esterases which can release biologically active subunits from the synthetic compounds. As shown in the present study, only one conjugate in each series gave satisfactory anti-tumor protection: namely, I-octyl butyrate and poly(ethylene glycol 1000) dibutyrate respectively. A single immune-stimulatory injection of purified Corynebacterium parvum extract prior to administration of the conjugates significantly increased the anti-tumor potency.

Cyclophosphamide-immunodepressed FVB/N mice: potentiating the effects of testicular cytomegalovirus infection.

The aim of this study was to investigate the effect of cyclophosphamide (CY) immunosuppression on the infection of germinal cells following testicular inoculation of male FVB/N mice with murine cytomegalovirus (MCMV). We used CY to modulate the immune status in order to mimic iatrogenic immunosuppression in humans (organ transplantation) as closely as possible. We show that viral pathological manifestations observed in mice treated with this CY-MCMV combination were severer than those observed in immunocompetent male mice infected with MCMV alone. As previously reported, the typical MCMV cellular inclusions were present in interstitial spaces; however, the spermatogenic cells were never directly infected. Nonetheless, at the end of our observation, we obtained definitive necrosis of the testes. These results suggest that germline cell necrosis induces sterility in immunodepressed infected male mice indirectly. In the case of organ transplantation, particular attention should be accorded to male patients receiving CY.

Isoprinosine increases the antitumor action of interferon.

The association of relatively low doses of interferon with an immunostimulant, isoprinosine, enhanced the antitumor effect of interferon. Each mouse was inoculated with 10(6) Crocker Tumor 180/TG cells. The best results were obtained when both interferon and isoprinosine were injected three times a week for 1 month. Under these conditions, the mean survival time increased from 26 days in the controls to 45 days in the interferon-treated group to 64 days when both agents were used. Isoprinosine alone had no effect. The final survival rate increased from 1 mouse out of 50 mice in the control group to 10 mice out of 50 in the interferon-treated groups and to 25 mice out of 50 with the combined treatment.