Pholiotic acid promotes apoptosis in human metastatic melanoma cells

Mushrooms produce a great variety of secondary metabolites that can be successful in both prevention and treatment of various cancers. In particular, higher Basidiomycete mushrooms contain various types of biologically active low-molecular compounds in fruiting bodies with suggested anticarcinogenic effects. The polyamine analogue {(2R)-2-[(S)-3-hydroxy-3-methylglutaryloxy] putrescine dicinnamamide} indicated with the name pholiotic acid, isolated for the first time by us from the fruiting bodies of the Basidiomycete Pholiota spumosa (Fr.) Sing. (Strophariaceae), inhibited the viability of human prostate cancer cells, such as other polyamine synthetic analogues that have shown antitumor activity in several types of cancer, including melanoma. Melanoma is an aggressive skin cancer that can metastasize to other organs and presents a high resistance to conventional therapies. In light of these considerations, the present study was therefore designed to assess whether this putrescine derivative could inhibit the growth of human metastatic melanoma cell lines, M14 and A2058. The results obtained demonstrate that this natural compound, at 12.5-50 μM concentration, was able to reduce cell viability of both cancer cells inducing cell death by intrinsic apoptotic pathway that probably involves PTEN activity, inhibition of Hsp70 expression and reactive oxygen species production. On the other hand, the increased expression of enzymes involved in polyamine catabolism trigger apoptotic cell death leading to polyamine depletion and generation of reactive oxygen species as by-products. In conclusion, these findings, starting point for further investigation, implement available our data to support pholiotic acid as an attractive potential chemopreventive agent, and provide a basis for further research into the use of this polyamine derivative as potential anticancer agent for melanoma in combination with existing therapies to improve treatment efficacy and overcome the obstacle of drug resistance.

A metabolomics-driven model for early remission prediction following vedolizumab treatment in patients with moderate-to-severe active ulcerative colitis

To predict early remission following anti-integrin therapy (vedolizumab [VDZ]) in patients with moderate-to-severe active ulcerative colitis (UC) using non-invasive biomarkers. The clinical data of a cohort of 33 patients with moderate-to-severe active UC admitted to the Department of Gastroenterology at Suzhou Municipal Hospital between January 2021 and December 2022 were collected. Of these, 9 patients declined VDZ treatment, and 21 received VDZ at doses of 300 mg weeks 0, 2, and 6, each administered within a 30-minute infusion period. The treatment regimen aimed to induce remission of clinical symptoms; hence, the same dose was administered every 8 weeks. At weeks 0 and 14, serum C-reactive protein (CRP) and erythrocyte sedimentation rate were measured using a modified Mayo score. In addition to clinical assessment, stool samples at baseline and weeks 14 were collected and evaluated using 16SrRNA gene sequencing and gas chromatography-mass spectrometry (GC-MS). Clinical remission was determined based on the clinical symptoms and partial Mayo scores. In patients who received VDZ, the strains of bifidobacterium longum (P = 0.022) and bacteroides sartorii (P = 0.039) significantly increased after treatment than before treatment. GC-MS analysis showed that taurine (P = 0.047) and putrescine (P = 0.035) significantly decreased after treatment. Furthermore, while acetamide exhibited a notable increase (P = 0.001), arachidic acid (P < 0.001) and behenic acid (P = 0.005) demonstrated statistically significant elevations. The combined prediction model of acetamide, taurine, and putrescine demonstrated a high predictive value of early remission in patients with moderate-to-severe active UC following VDZ treatment (area under the curve = 0.911, P = 0.014).

A combined ligand and target-based virtual screening strategy to repurpose drugs as putrescine uptake inhibitors with trypanocidal activity

Chagas disease, also known as American trypanosomiasis, is a neglected tropical disease caused by the protozoa Trypanosoma cruzi, affecting nearly 7 million people only in the Americas. Polyamines are essential compounds for parasite growth, survival, and differentiation. However, because trypanosomatids are auxotrophic for polyamines, they must be obtained from the host by specific transporters. In this investigation, an ensemble of QSAR classifiers able to identify polyamine analogs with trypanocidal activity was developed. Then, a multi-template homology model of the dimeric polyamine transporter of T. cruzi, TcPAT12, was created with Rosetta, and then refined by enhanced sampling molecular dynamics simulations. Using representative snapshots extracted from the trajectory, a docking model able to discriminate between active and inactive compounds was developed and validated. Both models were applied in a parallel virtual screening campaign to repurpose known drugs as anti-trypanosomal compounds inhibiting polyamine transport in T. cruzi. Montelukast, Quinestrol, Danazol, and Dutasteride were selected for in vitro testing, and all of them inhibited putrescine uptake in biochemical assays, confirming the predictive ability of the computational models. Furthermore, all the confirmed hits proved to inhibit epimastigote proliferation, and Quinestrol and Danazol were able to inhibit, in the low micromolar range, the viability of trypomastigotes and the intracellular growth of amastigotes.

Recent Advances in Fluorescent Methods for Polyamine Detection and the Polyamine Suppressing Strategy in Tumor Treatment

The biogenic aliphatic polyamines (spermine, spermidine, and putrescine) are responsible for numerous cell functions, including cell proliferation, the stabilization of nucleic acid conformations, cell division, homeostasis, gene expression, and protein synthesis in living organisms. The change of polyamine concentrations in the urine or blood is usually related to the presence of malignant tumors and is regarded as a biomarker for the early diagnosis of cancer. Therefore, the detection of polyamine levels in physiological fluids can provide valuable information in terms of cancer diagnosis and in monitoring therapeutic effects. In this review, we summarize the recent advances in fluorescent methods for polyamine detection (supramolecular fluorescent sensing systems, fluorescent probes based on the chromophore reaction, fluorescent small molecules, and fluorescent nanoparticles). In addition, tumor polyamine-suppressing strategies (such as polyamine conjugate, polyamine analogs, combinations that target multiple components, spermine-responsive supramolecular chemotherapy, a combination of polyamine consumption and photodynamic therapy, etc.) are highlighted. We hope that this review promotes the development of more efficient polyamine detection methods and provides a comprehensive understanding of polyamine-based tumor suppressor strategies.

[Combined blockade of GluR1 AMPA and NMDA receptors effectively eliminates neurological disorders in rats with experimental allergic encephalomyelitis]

The experimental allergic encephalomyelitis (EAE) developed on the 11 - 12th day after inoculation of encephalitogenic mixture in 96% of female Wistar rats in the control group. In the majority of control rats, severe EAE with a long duration of action prevailed (average cumulative index, 25.6; average duration of illness, 15.8 days). A course of NMDA-antagonist memantine administration in a doze of 10 and 20 mg/kg prevented the development of EAE in 10% of rats. In rats with EAE (on the average, 12-13 days after the administration of encephalitogenic mixture) the drug slightly reduced the severity and duration of neurological disorder: the average cumulative index and duration of illness decreased by a factor of 1.4-1.5 in comparison to the control. The antagonist of NMDA and GluR1 AMPA receptors, IEM-1913, upon a course of administration in a doze of 0.1-1 mg/kg prevented the EAE development in 23-25% of rats. In the rats with EAE treated with IEM-1913 in the maximum doze (1 mg/kg), the EAE developed only after completion of the course of drug administration (on the 19-20th day), proceeded quickly (no more than 5 days), and in the easy form (average cumulative index. 8.3). High efficacy of IEM-1913 administration in rats with EAE is apparently connected with its neuroprotective and antiinflammatory action, which is related, on the one hand, to a combined block of NMDA and GluR1 AMPA of receptors in brain and, on the other hand, to a reduction of the permeability of BBB for encephalitogenic T-lymphocytes owing to the blockade of NMDA receptors in BBB.

Putrescine-1,4-dicinnamide from Pholiota spumosa (Basidiomycetes) inhibits cell growth of human prostate cancer cells

Previously, it was isolated from the fruiting bodies of the gilled mushroom Pholiota spumosa (Basidiomycetes, Strophariaceae), putrescine-1,4-dicinnamide, a phenylpropanoid derivative conjugated with polyamine putrescine never isolated before as a natural compound. Recently, polyamine analogs that are similar in structure to the natural polyamines but that cannot mimic their functions that are essential for cellular growth and differentiation, have shown antitumor activity in several types of human cancer cells. Therefore, we have now investigated the response of DU-145 cells, a well characterized androgen-independent human prostate cancer (PCA) cell line, to this phenylpropanoid derivative. The results presented here demonstrate that putrescine-1,4-dicinnamide, as suggested for polyamine analogs synthesized artificially, inhibits the cell growth of cancer cells inducing apoptosis cell death, mediated, at least in part, by the activation of caspase cascades, that at higher doses shift to necrosis, through the increase of reactive oxygen species (ROS) generation.

Sensitization of human colon adenocarcinoma cells (LoVo) to reactive oxygen species by a lysosomotropic compound

The in situ formation of cytotoxic metabolites by an enzyme-catalyzed reaction is a recent approach in cancer therapy. The present results show that multidrug-resistant human colon adenocarcinoma cells (LoVo) are significantly more sensitive than corresponding wild-type cells to hydrogen peroxide and aldehydes, the products of bovine serum amine oxidase (BSAO)-catalyzed oxidation of spermine. Pre-treatment of the cells with N1,N4-bis(2,3-butadienyl)-1,4-butanediamine (MDL 72527), a lysosomotropic compound, sensitized both cell lines to the subsequent exposure to spermine metabolites, as was evident from the decrease of cell survival by a log unit. The sensitizing effect was greater in the case of the multidrug-resistant cell line, an aspect of particular importance with respect to potential therapeutic applications of the method, since conventional cancer therapy suffers from the development of drug resistance. Cell viability was determined using a clonogenic assay. MDL 72527 (at 300 microM) produced numerous cytoplasmic vacuoles, presumably of lysosomal origin, after 6-h exposure, which decreased in size and number (in the presence of the drug) by 24 h and had almost disappeared completely at 48 h. Mitochondrial damage, as observed by transmission electron microscopy, seemed to correlate better with the cytotoxic effects of the treatment than the formation of vacuoles. We suggest that the release of lysosomal enzymes into the cytosol by MDL 72527 is the main reason for its sensitizing effect. It is known that lysosomotropic compounds, which release lysosomal enzymes, produce oxidative stress and apoptosis.

The hepatoprotective effect of putrescine against cadmium-induced acute liver injury

The hepatoprotective effect of putrescine against cadmium liver injury was investigated. Male Wistar rats were injected with a dose of cadmium (6.5 mg CdCl(2)/kg bodyweight, intraperitoneally). Normal saline (group I) or putrescine (300 micro mol/kg bodyweight; group II) were injected 2, 5 and 8 h later. A number of animals of both groups were killed 0, 12, 16, 24, 48 or 60 h after cadmium intoxication. Liver tissue was histologically assessed for necrosis, apoptosis, peliosis, mitoses, and inflammatory infiltration. Apoptosis was also quantified by the TUNEL assay for hepatocytes and nonparenchymal liver cells. The discrimination between hepatic cell subpopulations was achieved histochemically. The mitotic index in hematoxylin-eosin-stained sections and by the immunochemical detection of Ki67 nuclear antigen, (3)H-thymidine incorporation into hepatic DNA, and hepatic thymidine kinase activity were all used as indices of liver regeneration. Both hepatocyte apoptosis and liver necrosis evolved in a biphasic temporal pattern. Nonparenchymal cell apoptosis and peliosis hepatis evolved in a monophasic pattern and were correlated closely. Putrescine administration totally reversed liver necrosis and hepatocyte apoptosis. The time profile of nonparenchymal apoptosis was altered and peliosis hepatis was also totally attenuated. In conclusion, putrescine protected hepatocytes and modulated the mechanism of cadmium-induced acute hepatotoxicity.

Inhibition of arterial thrombosis by polyamines in a canine coronary artery injury model

Polyamines are polycations present in all living organisms and have been shown to play an important role in various physiological functions. Previous studies have shown that various amines including polyamines inhibit platelet activation. Among the amines tested tetra-amine, spermine is the potent inhibitor of platelet aggregation. In spite of vast literature on the anti-aggregatory effect of amines, there are no definitive studies testing their efficacy in an in vivo thrombosis model. In the present study, we investigated if polyamines could inhibit in-vivo thrombosis. A partially occlusive thrombus was generated by application of electric current in canine coronary artery. In control animals, the artery was completely in 76+/-14 min after the current was discontinued. When 40 mg/kg (1.44 mM) spermine was given immediately after stopping the current blood flow remained patent for >240 min. At equimolar concentration, triamine, spermidine and diamine putrescine are also equally effective in preventing thrombus development. The anti thrombic effect of polyamines was not associated with increased bleeding tendency, as judged by the amount of blood adsorbed by a gauge pad placed in a surgical incision extending to the muscle tissue and by a standard template bleeding. These results indicate that apart from inhibiting in-vitro platelet aggregation polyamines can also inhibit in-vivo thrombus formation.

(Z)-1,4-diamino-2-butene as a vector of boron, fluorine, or iodine for cancer therapy and imaging: synthesis and biological evaluation

Polyamine vectors are attractive for tumor targeting. We envisaged (Z)-1,4-diamino-2-butene (Z-DAB), an unsaturated analogue of putrescine as vector of (10)B, (18)F and (131)I for boron neutron capture therapy (BNCT), and tumor imaging by positron emission tomography or scintigraphy respectively. In the present work, the synthesis and characterization of new derivatives of Z-DAB were reported. Z-DAB was actively transported in cells via the polyamine transport system and converted into the spermidine analogue.(E)-2-iodo-1,4-diamino-2-butene (E-I-DAB) was not taken up by the polyamine transport system and may not be suitable for tumor imaging. In contrast, (Z)-2-[4-(5,5-dimethyl-dioxaborinan-2-yl)phenyl]methyl-1,4-diamino-2-butene (Z-4-Bbz-DAB) was a substrate of the transport system and allowed significant boron accumulation in 3LL cells. Its potential in BNCT will be evaluated.

Synthesis of diaminobutane derivatives as potent Ca(2+)-permeable AMPA receptor antagonists

We synthesized diaminobutane derivatives as potent Ca(2+)-permeable AMPA receptor antagonists with non-hypotensive activity. Compound 10c showed selective Ca(2+)-permeable AMPA receptor antagonist activity and neuroprotective effects in transient global ischemia models in gerbils.

Inhibition of platelet aggregation by putrescine, spermidine, and spermine in hypercholesterolemic rabbits

BACKGROUND

Hypercholesterolemia causes alterations in platelet function. Platelet hyperaggregation is considered a predisposing factor for atherosclerosis. In this paper, the antiaggregating effect of the polyamines putrescine, spermidine, and spermine was studied on platelets of normal and hypercholesterolemic rabbits.

METHODS

New Zealand rabbits were fed with a cholesterol-enriched diet for 10 weeks. Lipids and glucose were determined in serum. The assays of platelet aggregation were carried out using platelet-rich plasma (PRP) obtained from both control and cholesterol-fed rabbits. We used 2.5 micromol /mL ADP and 2 microg/mL collagen as inductors of platelet aggregation. In addition, arginase activity and L-arginine content were determined in PRP.

RESULTS

Serum total cholesterol and LDL-cholesterol concentrations were increased from 26.3 +/- 8.1 to 1,485.0 +/- 26.8 mg/dL and from 15.9 +/- 5.9 to 1,383.8 +/- 58.9 mg/dL, respectively, whereas triglyceride concentration increased from 88.3 +/- 35.6 to 411.0 +/- 154.5 mg/dL upon cholesterol feeding. Seventy-five percent of platelet aggregation inhibition was observed with 10 microM of polyamines in PRP of normal rabbits. Spermine inhibited platelet aggregation by 54% in PRP of hypercholesterolemic rabbits when ADP was used as agonist. The order of polyamine action was spermine > spermidine > putrescine. In addition, we found that platelet arginase activity and L-arginine content were unaltered upon hypercholesterolemia.

CONCLUSIONS

These results show that the polyamines putrescine, spermidine, and spermine have antagonist action in platelet aggregation and suggest a key role of polyamines in platelet aggregation under normal and hypercholesterolemic conditions.

Effect of the polyamine oxidase inactivator MDL 72527 on N(1)-(n-octanesulfonyl)spermine toxicity

N(1)-(n-octanesulfonyl)spermine (N(1)OSSpm) is a potent calmodulin antagonist. In the present work, its toxicity to DHD/K12/TRb and CaCo-2 cells, two colon carcinoma-derived cell lines, was studied with the aim to identify those properties of the cells, which determine their sensitivity to N(1)OSSpm and related structures. Exposure of the cells to MDL 72527, a compound considered to be a selective inactivator of polyamine oxidase (PAO) increased the cytotoxicity of N(1)OSSpm to both cell lines. In contrast, toxicity of trifluoperazine, a calmodulin antagonist with a polyamine-unrelated structure, was not enhanced by MDL 72527. Combined exposure of cells to 2-(difluoromethyl)ornithine (DFMO) (a selective inactivator of ornithine decarboxylase), MDL 72527 and N(1)OSSpm produced a synergistic cytotoxic effect. Neither the intrinsic PAO activity of the cells (as determined with N(1), N(12)-diacetylspermine as substrate), nor their ability to accumulate the drug was a determinant of the cytotoxic effect of N(1)OSSpm. These data suggest that MDL 72527 has a target unrelated to PAO, which is responsible for the enhancement of N(1)OSSpm (and spermine) toxicity. Identification of this target may be of use if the therapeutic potentials of MDL 72527 are to be exploited.

Prevention by L-arginine and polyamines of delayed development and embryotoxicity caused by chemically-induced diabetes in rats

Diabetes mellitus induction with alloxan at a dose of 110 mg/kg i.p. in rats on Day 4 of pregnancy causes delayed development and resorptions as signs of embryotoxicity. In the present study, the administration of human NPH insulin at doses of 1 to 5 U/d to rats or 1.0 mL of 10 mM L-arginine for 8 d, starting the day following diabetes induction, prevented embryotoxicity and delayed development. Similar results were obtained when the polyamines putrescine, spermidine, or spermine were administered at doses of 1.0 mL of a 10 microM solution to each rat daily. However, even though L-arginine and polyamines prevented adverse effects of severe diabetes on the conceptus, and caused normalization of glucose, beta-hydroxybutyrate levels remained elevated. These results support the hypothesis that the mechanisms of normal and altered development could be mediated by the action of polyamines.

Putrescine-modified catalase with preserved enzymatic activity exhibits increased permeability at the blood-nerve and blood-brain barriers

Much evidence exists in support of the hypothesis that free radicals contribute to the pathogenesis of several neurodegenerative disorders and that mechanisms of free radical generation occur both intracellularly and extracellularly. Previous studies in this laboratory have shown that covalent modification of growth factors and antioxidant enzymes with the naturally occurring polyamine, putrescine, increases their permeability at the blood-nerve and blood-brain barriers (BNB and BBB), but does not significantly inhibit bioactivity. Furthermore, putrescine-modified superoxide dismutase (SOD) was shown to reduce neurodegeneration in a rat model of global cerebral ischemia. The purpose of the present study was to modify the antioxidant enzyme, catalase (CAT), with putrescine (PUT) at carboxylic acid groups whose ionization, and hence reactivity, was controlled with pH and investigate the effects on permeability and enzymatic activity. Modification of CAT with PUT increased its permeability 2-3-fold and preserved 67% of its enzymatic activity compared to native CAT and 137% compared to lyophilized CAT. The results of this study indicate that modification of CAT with putrescine increases its permeability while preserving enzymatic activity. PUT-SOD administered in combination with PUT-CAT may eliminate both the superoxide radical and the H2O2 produced from the dismutation of superoxide, respectively, and thus prevent the formation of hydroxyl radicals. This combination may exhibit increased neuroprotective effects, compared to native enzymes, following systemic administration for the treatment of free radical associated neurodegenerative disorders.

Oral administration of putrescine inhibits Cryptosporidium parvum infection of neonatal C57BL-6 mice and is independent of nitric oxide synthesis

We examined the efficacy of oral administration of putrescine (a byproduct of arginine metabolism) in the prevention of Cryptosporidium parvum infection of neonatal C57BL-6 mice. Mice were challenged with the parasite at 7 days of age. Mice receiving putrescine from 3 through 10 days of age had a delayed pattern of infection as compared with control mice. Mice receiving putrescine from 3 through 21 days of age did not become infected, whereas control mice were heavily infected. We also tested the hypothesis that putrescine inhibited C. parvum infection by enhancing nitric oxide (NO) production. Mice receiving the NO inhibitor N omega-L-arginine methyl ester (L-NAME) parenterally and putrescine orally did not become infected. Thus, it appears that putrescine inhibits C. parvum infection in an NO-independent manner.

The role of the polyamine inhibitor eflornithine in the neuropathogenesis of experimental murine African trypanosomiasis

The treatment of late-stage human African trypanosomiasis is complicated by a post-treatment reactive encephalopathy, also referred to as a 'reactive arsenical encephalopathy', that may be fatal. This study used a well established experimental mouse system to assess the use of the trypanostatic drug, eflornithine, in the management of this post-treatment reaction. Female CD-1 mice infected with an eflornithine-resistant trypanosome stabilate and treated with the trypanocidal compound diminazene aceturate on or after day 21 post-infection develop a reactive encephalopathy and relapsing parasitaemia. If these animals are re-treated with diminazene aceturate, a severe encephalopathy develops histologically comparable with that of human cases and characterized by a severe meningoencephalitis and astrogliosis. Histopathological and immunocytochemical examination shows that administration of eflornithine before or after the development of this reactive encephalopathy prevented or ameliorated the inflammatory reaction. Since an eflornithine resistant stabilate was used, this effect appears to be independent of the drug's trypanostatic action and illustrates an important, previously unrecognized, pharmacological property of eflornithine. Consideration can now be given to the use of eflornithine for the management of human trypanosomiasis cases, even where trypanosome resistance to eflornithine exists.

Topical putrescine (Fibrostat) in treatment of hypertrophic scars: phase II study

Previous studies indicated that tissue transglutaminase plays a role in the cross-linking of type III procollagen in wound matrices and that this may be inhibited by 50 mM putrescine in vitro. For this reason, the clinical effect of 50 mM putrescine in a eutectic vehicle (Fibrostat) was studied in this phase II double-blind crossover study in 43 patients. Twenty of the patients had had recent surgery and were studied for product safety rather than efficacy. No toxic effects were observed in this group of patients, and only 1 of the 23 unoperated patients had a rash during treatment. The observed effect of Fibrostat versus sham treatment of 1 month's duration in active hypertrophic scar was a significant improvement of hypertrophy in 23 patients during the Fibrostat treatment arm, regardless of the order in which treatment was received. It is suggested that Fibrostat is a safe therapeutic agent for treatment of hypertrophic scar. Clinical examples to illustrate its use are given.

[The involvement of polyamines in the malignant proliferative process. The anticancer effect of polyamine deprivation]

The fact that tumors require polyamines for growth has been repeatedly demonstrated. In vivo polyamines are available both from endogenous (intracellular biosynthesis) and exogenous sources (food and intestinal microflora). We investigated in rats grafted with Mat-Lylu prostatic adenocarcinoma the distribution between tumor and tissues of orally administered (14C) putrescine (Pt). The amount of radioactivity retained by tumors was directly proportional to the tumor volume. In a tumor of 25 cm3 19% of the totally retained radioactivity was found. The accumulation of Pt by intestinal brush-border membrane vesicles prepared from tumor-bearing animals was significantly higher than by vesicles from healthy rats. Our results indicate that the presence of a tumor induces an adaptive response in the small intestine which stimulates the uptake of exogenous polyamines. Our therapeutic strategy was to realise a total blockade of all endogenous and exogenous sources of polyamines by feeding animals with a drug (DFMO, MDL 72527, antibiotics) containing polyamine deficient chow. We observed that polyamine deprivation largely reduced both primary tumor and metastatic development. Natural Killer cell cytotoxic activity and blood formula were restored to normal values after treatment. Furthermore polyamine deprivation enhanced anti-tumoral efficacy of chemotherapy.

[Protective effect of putrescine on oleic acid-induced respiratory distress syndrome (RDS)]

The effect of putrescine on oleic acid-induced RDS were studied in rat, it was found that preadministration of putrescine to rat with RDS significantly improved its hypoxemia, pulmonary edema and histologic injury; inhibited the leakage of protein from plasma; lowered increase of pulmonary lipid peroxidation products (malondialdehde, MDA). The result suggests that putrescine could have significant potential for clinical treatment of acute pulmonary injury.

Protective action of putrescine against rat liver injury

The hepatoprotective action of orally dosed putrescine was investigated using rat models of liver injury. When rats received putrescine orally soon after a dose of carbon tetrachloride or D-galactosamine, deranged serum alanine aminotransferase values and prothrombin times were significantly attenuated compared with control levels, with improved histologic extent of liver injury. Putrescine addition to the medium of rat hepatocytes in primary culture reduced cell killing induced by D-galactosamine or the membrane detergents chenodeoxycholic acid and Triton X-100. Similar reduction was seen in cells exposed to tert-butyl hydroperoxide (TBHP), an agent producing cell death through lipid peroxidation, with attenuation of cellular malondialdehyde content. Putrescine also significantly attenuated the extent of increased plasma membrane microviscosity as assessed with 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene in TBHP-treated cells. These results suggest that orally given putrescine protects against liver injury. Plasma membrane stabilization and reduction of lipid peroxidation may contribute to this hepatoprotection.

The growth of MAT-LyLu rat prostatic adenocarcinoma can be prevented in vivo by polyamine deprivation

The combination of inhibitors of ornithine decarboxylase and polyamine oxidase, and of antibiotics suitable for the (partial) decontamination of the gastrointestinal tract, with a polyamine deficient diet, is responsible for the almost complete inhibition of the growth of MAT-LyLu prostatic adenocarcinoma. In the tumor-bearing animals, erythrocyte spermidine levels were reduced, but spermine concentrations were increased. As has been previously observed, the increase in erythrocyte spermine level was associated with an enhancement of malignant cell death. Adriamycin administration did neither diminish tumor growth, nor potentiate the antitumor effect of polyamine deprivation treatment. Interruption of the polyamine deprivation treatment was accompanied by a significant enhancement of tumor growth. Since polyamine deprivation causes only reversible growth inhibition, it seems not appropriate as a monotherapy.

Effect of polyamine deprivation on the survival of intracranial glioblastoma bearing rats

It has previously been shown that systematic polyamine deprivation results in the almost complete inhibition of the growth of several solid tumors. The same polyamine deficient diet (containing antibiotics for the decontamination of the gastrointestinal tract, the ornithine decarboxylase inhibitor 2-(difluoromethyl)ornithine, and the polyamine oxidase inhibitor N1, N4-bis-(2,3-butadienyl)putrescine; "drug-containing polyamine deficient chow", DC-PDC) was applied for the first time to the treatment of rats with an intracranial tumor. Rats received intracortical grafts of C6 rat glioblastoma cells, and the length of their survival was determined. Treatment with DC-PDC, starting four days after tumor cell inoculation, significantly prolonged the median survival of the glioblastoma-bearing rats. The results underline the general growth inhibitory effect of systematic polyamine deprivation. Since the effect of polyamine restriction on tumor growth is reversible, combinations with cytotoxic drugs have to be found which exploit the changed functions of polyamine deficient tumor cells.

Inhibition of the growth of U-251 human glioblastoma in nude mice by polyamine deprivation

An almost complete prevention of tumor growth was achieved in U-251 human glioblastoma xenografted nude mice, by partial decontamination of the gastrointestinal tract and feeding of a polyamine-free diet containing inhibitors of ornithine decarboxylase (DFMO) and of polyamine oxidase (MDL 72527). After one week of polyamine deprivation, spermidine concentrations were lowered, and spermine levels were increased in all tissues. In contrast, putrescine concentrations were only reduced in tumor and in brain. Erythrocyte polyamine determinations revealed differences similar to those observed in tissues: spermidine concentration was lowered by 50% and spermine level was 3-fold increased. If this or related treatments should become of therapeutic importance in the future, then the determination of erythrocyte polyamine levels might be of diagnostic value.

Potentiation of natural killer cell activity and tumor immunity by diacetylputrescine

The objective of the present investigation was to evaluate the immunomodulating properties of tetramethylenebisacetamide (N,N' 1-diacetylputrescine, DAP), a known inducer of cellular differentiation. We examined the effect of DAP administration in vivo on splenic and nonadherent peritoneal natural killer (NK) cell activity. A single i.p. injection of DAP (100 mg/kg) enhanced cytolytic activity directed against YAC-1 and MCA-38 tumor target cells 2- to 3-fold. Cytolytic activity peaked 3 days following DAP injection. DAP treatment increased the frequency of asialo-GM1-positive splenocytes to 15% compared with 5% for vehicle treated controls. Furthermore, cytolytic activity could be eliminated by treatment with anti-asialo-GM1 antibodies and complement. Lysis of NK-resistant P815 and EL4 tumor target cells was not observed in leukocytes from DAP-treated mice. DAP treatment of mice given injections i.p. of MCA-38 tumor cells increased survival time of the mice by 37%, curing 10% of the animals of the tumor. DAP treatment of mice given injections intrasplenically of MCA-38 tumor cells reduced both the number and the size of the hepatic metastases. The antitumor effect of DAP in vivo could be eliminated by pretreating mice with anti-asialo-GM1 antibodies or utilizing NK cell deficient beige (bg/bg) mice. These results indicate that the observed anti-tumor activity of DAP is mediated, at least in part, by NK cells.

Endogenous and exogenous polyamines in support of tumor growth

The combination of inhibitors of ornithine decarboxylase and polyamine oxidase and of antibiotics suitable for the (partial) decontamination of the gastrointestinal tract with a polyamine-deficient diet reduced the growth rate of Lewis lung carcinoma by more than 80%. The formation of lung metastases was prevented by 70 to 100%, depending on the treatment. The reduction of tumor growth was accompanied by a decrease of tissue polyamine concentrations, a reduced rate of tumor cell proliferation, and protein synthesis. The comparison of the ornithine decarboxylase inhibitors Eflornithine [D,L-2-(difluoromethyl)ornithine] and (E)-2-(fluoromethyl)dehydroornithine ethylester confirmed the greater in vivo potency of the latter compound. Our method of growth inhibition by systematic polyamine deprivation is not tumor specific, but presumably generally applicable to rapid growth.

Methylacetylenic putrescine (MAP), an inhibitor of polyamine biosynthesis, prevents the development of collagen-induced arthritis

The objective of the present investigation was to examine the effects of an irreversible inhibitor of ornithine decarboxylase (2R,5R)-6-heptyne-2,5,diamine (methylacetylenic putrescine, MAP) on experimentally induced arthritis in mice. MAP (0.5-0.05%) was administered in drinking water to DBA/1 mice immunized with native chick type II collagen (CII). The development of arthritis was inhibited only in those mice receiving 0.5% MAP; lower doses were ineffective. Putrescine and spermidine levels were decreased and spermine levels were increased in spleen and lymph node cells from drug-treated mice compared to control arthritic mice. Furthermore, when control mice were developing arthritis, serum anti-CII antibody levels were lower in the MAP-treated group. MAP inhibited antibody production early in the immune response to CII; there was an association between inhibition of antibody production and inhibition of the development of arthritis. When MAP was discontinued, the nonarthritic, drug-treated mice did not develop the disease. Late administration of MAP (beginning 19 days after CII immunization) did not affect the incidence or the severity of the arthritis. Cyclophosphamide treatment begun at the same time significantly inhibited the development of the disease. In vitro T cell responses to denatured type II collagen (dCII) in untreated and MAP-treated mice were examined 14 days after immunization with CII. This is a time of peak T cell responsiveness in untreated animals. MAP treatment had no effect on the T cell response to dCII. These results indicate that MAP can prevent the development of CII-induced arthritis, possibly by inhibiting the autoantibody response. Therefore, inhibitors of polyamine biosynthesis deserve further investigation as potential immunosuppressive agents.

Phase I study of methylacetylenic putrescine, an inhibitor of polyamine biosynthesis

In a phase I clinical trial, nine patients with advanced malignancies not amenable to alternative therapy received alpha-methyl-delta-acetylenic putrescine (MAP), an enzyme-activated, irreversible inhibitor of ornithine decarboxylase (ODC). MAP was given orally in increasing doses to successive groups of three patients as follows: 375 mg, 750 mg and 1500 mg/day, given as three equally divided doses for 4 weeks. Doses of 375 and 750 mg/day were well tolerated, with no detectable toxicity. Of three patients receiving 1500 mg/day, two experienced moderate to severe myelosuppression; one of these also became anuric, requiring the discontinuation of therapy after 9 days. Both effects were reversible after treatment was stopped. No objective responses were observed, with five patients having stable disease and four, progressive disease during the study period. In the seven patients in whom it could be calculated, the plasma elimination half-life t1/2 of MAP measured on the last day of treatment was between 3.9 and 9.2 h in six patients (mean, 5.6 h) and 26.1 h in the seventh. Mean steady-state trough concentrations of MAP were 2.3 mumol after the 375 mg/day dose, 7.1 mumol after 750 mg/day and 16.6 mumol after dosing with 1500 mg/day for 4 weeks, the levels after each treatment schedule being sufficient to inhibit ODC as demonstrated by increases in the urinary excretion of decarboxylated S-adenosylmethionine (dc-SAM). MAP treatment was associated with mean maximal increases in the urinary excretion of dc-SAM of 2.6-, 9.3- and 17.9-fold after 375, 750 and 1500 mg/day for 4 weeks, respectively, but no consistent changes in the urinary excretion of the polyamines, putrescine, spermidine or spermine were observed. Thus, the 24-h urinary excretion of dc-SAM may be used as a conveniently accessible marker of ODC inhibition in cancer patients.

Cytotoxic activity of a polyamine analogue, monoaziridinylputrescine, against the PC-3 human prostatic carcinoma cell line

We have previously demonstrated that prostate and prostate-derived rodent tumors can be manipulated into increasing their accumulation of radiolabeled putrescine by alpha-difluoromethylornithine (DFMO)-induced depletion of intracellular putrescine and spermidine. As methods which increase intracellular accumulation of cytotoxic agents often increase the chemotherapeutic effectiveness of the agent, we examined whether an alkylating derivative of putrescine would be cytotoxic to tumor cells. We present here our findings on the cytotoxicity of the aziridinyl derivative of putrescine (AZP) against prostatic cancer cells. The apparent Km for putrescine was 2.5 microM with or without DFMO pretreatment and the apparent Ki for AZP was 1 microM with or without DFMO pretreatment. Intracellular polyamine depletion by DFMO pretreatment resulted in a 3.7-fold greater accumulation of AZP compared to non-DFMO-treated cells. The growth inhibitory activity of AZP was increased with prior polyamine depletion by DFMO with the 50% effective dose decreasing from 18 microM to 2.1 microM. Putrescine was able to block the cytotoxic effect of AZP. Putrescine was also able to rescue the AZP-treated PC-3 cells for up to 6 h following a 1-h exposure to AZP. It appears that aziridinylputrescine behaves like putrescine in that it competes with putrescine for uptake into the cell and, like putrescine, has its uptake into the cell increased by prior polyamine depletion. It differs from putrescine in that it expresses cytotoxic activity and inhibits the growth of the human prostate-derived PC-3 cell line. This cytotoxic activity is also increased by prior polyamine depletion. The cytotoxic behavior of AZP is dependent both on the concentration and duration of exposure. Putrescine can rescue the cells from the effect of AZP. AZP is a potentially useful cytotoxic analogue that utilizes the polyamine transport system for its uptake into the cell.

Relative abilities of bis(ethyl) derivatives of putrescine, spermidine, and spermine to regulate polyamine biosynthesis and inhibit L1210 leukemia cell growth

It has been shown previously (Porter et al., Cancer Res., 45: 2050-2057, 1985) that the N1,N8-bis(ethyl) derivative of spermidine has significant antiproliferative activity which appears to derive from its regulatory effects on the polyamine biosynthetic pathway, particularly on ornithine decarboxylase activity. In the present study, N1,N4-bis(ethyl)putrescine (BEP) and N1,N12-bis(ethyl)spermine (BESm) were compared with N1,N8-bis(ethyl)spermidine (BES) in their ability to inhibit cell growth and regulate polyamine biosynthesis. With cultured L1210 murine leukemia cells, the IC50 values at 48 h were approximately 2 mM for BEP, 30 microM for BES, and 1 microM for BESm making the latter the most effective polyamine inhibitor or analogue thus far identified. At concentrations which approximated IC50 values and yielded similar intracellular concentrations at 48 h (1500-2000 pmol/10(6) cells), the effects of the analogues on polyamine biosynthesis generally correlated with their antiproliferative activity. BEP, at 1 mM, exerted relatively minor effects on polyamine biosynthesis. By contrast, 100 microM BES totally eliminated ornithine decarboxylase activity, depleted putrescine and spermidine pools, and decreased spermine pools by 40%. AdoMet decarboxylase activity was lowered slightly. The most impressive effects were obtained with 10 microM BESm which decreased ornithine and AdoMet decarboxylase activities by 99 and 84%, respectively; depleted putrescine and spermidine pools; and decreased spermine pools by 73%. None of the analogues, at 1 or 3 mM, had significant direct inhibitory effects on the decarboxylase activities from untreated cells with the exception of BESm which inhibited ornithine but not AdoMet decarboxylase activity. Thus, the effects of the analogues on these enzymes in treated cells are presumed to be mainly mediated by regulatory mechanisms. In this regard, BESm was superior to BES since both ornithine and AdoMet decarboxylase activities were suppressed. Given its unique activities, BESm would seem to have potential as both an antiproliferative agent and also as an experimental probe for studying regulation of the polyamine pathway, particularly AdoMet decarboxylase.

Putrescine dependent growth of mycoplasma infected mammalian cells

The aliphatic diamine putrescine, a metabolic precursor of the polyamines spermidine and spermine, markedly stimulated the growth of a murine lymphoblastoid cell line (R 1.1) infected with Mycoplasma orale, under conditions of arginine limitation. The diamine acted by suppressing the growth of the mycoplasma, which use arginine as a major energy source, and thereby prevented the depletion of arginine from the medium. The antimycoplasmal effects of putrescine occurred at concentrations that were neither stimulatory nor toxic to uninfected cells.

[Therapy of prostate carcinoma with polyamine synthesis inhibitors. I. Physiological and pathophysiological principles]

The therapeutic concept of irreversible inhibition of both ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) by alpha-difluoromethylornithine (DFMO) and methylglyoxal bis-guanylhydrazone (MGBG) is based on pathologic activities of these enzymes in tumor tissue. The polyamines putrescine, spermidine and spermine are measured in highest concentration in the prostate of both men and animals, with a significant increase of spermine in benign hyperplasia of the prostate. Patients with metastatic cancer of the prostate have elevated putrescine levels in the 24-hour urine. Treatment with 3 or 1% DFMO or 11 mg/kg MGBG in transplantable human and experimental cancer of the prostate demonstrated a significant anti-growth effect. A combination of DFMO and MGBG is tumor-destructive. The combination of 1% DFMO and 11 mg/kg MGBG distinctly reduces the activity of ODC and SAMDC and significantly lowers the levels of putrescine, spermidine and spermine in the tumor.

Changes in polyamine metabolism of rat liver after administration of D-galactosamine. Favorable effects of putrescine administration on galactosamine-induced hepatic injury

There are many reports showing a close relation between polyamine metabolism and tissue growth or recovery of damaged tissues, such as regenerating liver. Thus, changes in polyamine metabolism in the livers from rats treated with D-galactosamine, an inducer of experimental hepatitis, were studied. The activity of ornithine decarboxylase started to increase 14 hr after administration of galactosamine and reached 30 times the normal activity at about 25 hr, the time of maximum severity of hepatitis. The content of putrescine increased to about 10 times the control value. After increases in the putrescine content and ornithine decarboxylase activity, the hepatitis started to diminish. Increases in the activity of S-adenosylmethionine decarboxylase and the content of spermidine were observed 33-37 hr after administration of galactosamine. The maximum values of these parameters, which were significantly higher than the control values, were observed after the healing process had started.