Jacques-Philippe Moulinoux

Natural Alkylglycerols Restrain Growth and Metastasis of Grafted Tumors in Mice

Alkylglycerols are natural etherlipids abundant in shark liver oil (SLO) in a diacylated form. SLO is known to have antitumor properties and was recently described as an inhibitor of tumor neovascularization. However, most studies did not discriminate between the respective activities of alkylglycerols and of fatty acids, which both have potent biological properties. In this work, a mouse model was used to investigate the antitumor effects of SLO and of alkylglycerols purified from the same source, both administered orally. We demonstrated that either pure alkylglycerols or SLO reduced the tumor growth in a similar manner, suggesting that alkylglycerols were involved in this effect. In alkylglycerol-treated mice, metastasis dissemination was reduced by 64 ± 8%, whereas SLO effect was 30 ± 9% below control. Purified alkylglycerols also decreased significantly plasmalogen content in tumors, whereas SLO had no such effect. Finally, we demonstrated that a 5-day treatment with alkylglycerols curtailed the presence in tumors of von Willebrand factor, a marker of endothelial cells. This result suggested an anti-angiogenic effect of alkylglycerols. In summary, alkylglycerols were shown to decrease the growth, vascularization, and dissemination of Lewis lung carcinoma tumors in mice. These findings suggest that the antitumor activity of SLO is likely mediated by the presence of alkylglycerols.

Atmospheric pressure chemical ionization-mass spectrometry method to improve the determination of dansylated polyamines.

Determination of polyamine pools is still a step impossible to circumvent in studies aimed at determining the pathophysiological role of natural polyamines. In addition, polyamine measurement in biological fluids and tissues may have clinical relevance, especially in cancer patients. Among the wide panel of analytical methods developed for the quantification of polyamines, high-performance liquid chromatographic (HPLC) separation of polyamines after derivatization with dansyl chloride remains the most commonly used method. In this work, we show that atmospheric pressure chemical ionization-mass spectrometry (MS) can be used to detect and quantify biologically relevant polyamines after dansylation, without chromatographic separation. Positive-ion mass spectra for each dansylated polyamine were generated after optimization by flow injection analysis (FIA). FIA coupled with MS detection by selected ion monitoring greatly increased the sensitivity of the polyamine detection. The method is linear over a wide range of polyamine concentrations and allows detection of quantities as low as 5 fmol. The FIA/MS method is about 50-fold more sensitive than the conventional HPLC/fluorimetry procedure. A good correlation (r>0.98) between these two methods was observed. The FIA/MS method notably reduces the time of analysis per sample to 1.5 min and turns out to be rapid, efficient, cost saving, reproducible, and sufficiently simple to allow its routine application.

Polyamine profiles in tumor, normal tissue of the homologous breast, blood, and urine of breast cancer sufferers.

Polyamines are involved in the development of breast cancer. We assayed polyamines in erythrocytes, urines, and breast tissues (tumor tissue and histologically normal breast tissue close to the tumor) of patients with invasive breast cancer (n=174) and benign breast disease (n=71, used as controls). Polyamine levels in red blood cells and urine were similar to the polyamine concentrations found in healthy subjects, and thus cannot be used as diagnostic markers of breast cancer. In cancer tissue, polyamines were significantly increased in comparison with the polyamine concentrations in controls, and were correlated to the tumor aggressiveness as evaluated by histological grade and Ki-67 proliferative index. On the other hand, correlation was found between polyamine levels in the tumor and the status of the hormone receptors. In the mammary tissue close to the cancer, polyamines dramatically decreased in comparison with the polyamine levels of tissue samples removed around the histologically proven benign tumors. The changes of the polyamine concentrations in the histologically normal breast tissue in the vicinity of the cancer could play a role in the cancer development and need further studies, especially if polyamines are considered as a potential therapeutic target in breastcancer.

Antioxidative properties of natural polyamines and dimethylsilane analogues

Abstract Structural analogues of natural polyamines, which contain a –Si(CH3)2 group in the central carbon chain, have previously been found to be cytotoxic to various tumor cell lines in vitro and to inhibit tumor cell growth in experimentally grafted animals. In the present study, the antioxidative properties of dimethylsilane polyamine analogues were analyzed in comparison with the natural polyamines. Reactivities of these various polyamines against superoxide anions (generated from the hypoxanthine/xanthine oxidase reaction) and peroxyl radicals (produced from the thermal decomposition of water-soluble 2,2′-azo-bis-[2-amidinopropane] hydrochloride) were investigated. The dimethysilane analogues, and more particularly the hexamine derivative, exhibited the highest scavenging efficiency towards these two reactive oxygen species (ROS). Furthermore, analysis of their ability to prevent hydroxyl radical formation and to trap this ROS showed that the efficiency of the hexamine as a metal chelator and hydroxyl radical scavenger is similar to that of spermine. The higher antioxidant efficiency of the dimethylsilane polyamine analogues with respect to spermidine, together with their ability to displace this polyamine, essential for the promotion of cell growth, from its cellular anionic binding sites that are particularly prone to oxidation, could be biologically relevant and contribute to their in vivo cytotoxic effect and anti-tumor activity. Further experiments will be necessary to demonstrate clearly the relationship between their antioxidant properties and their antiproliferative effects.

(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.

Erythrocyte polyamines and prognosis in stage D2 prostatic carcinoma patients.

We studied 43 patients with newly diagnosed, untreated, stage D2 prostatic carcinoma, and correlated the initial performance status, hemoglobin, prostate specific antigen levels, tumor Gleason grade, extent of disease on the bone scan, and erythrocyte spermidine and spermine levels with progression. Three patients died of unrelated causes and were excluded from the study, 16 remained in remission with a mean 28 +/- 11 months of followup and 24 had progression (18, or 75%, of whom died of the cancer) with a mean 12 +/- 9 months of followup (p < 0.05 for followup) after initiation of hormonal therapy. Pretreatment performance status, hemoglobin, and erythrocyte spermidine and spermine levels were correlated with progression, hemoglobin and spermine being the most significant independent variables (p = 0.006 and p = 0.001, respectively). Concerning cause-specific survival, only hemoglobin and spermine erythrocyte levels were significant independent variables (p = 0.02 and p = 0.0025, respectively). If confirmed, polyamine erythrocyte levels obtained by a simple blood sample could discriminate at diagnosis patients with a high risk of rapid hormonal relapse who may benefit from a more aggressive primary management.

An evaluation of a polyamine-deficient diet for the treatment of inflammatory pain

Polyamines are thought to be involved in the regulation of numerous metabolic and electrophysiological processes in the nervous system. In this study we evaluated the effect of a synthetic polyamine-deficient diet on pain in a carrageenan (Car)-induced inflammatory rat model. Inflammation was induced with a unilateral subcutaneous injection of Car in a plantar hindpaw in rats fed without (control group) or with (deficiency group) a polyamine-deficient diet. Ipsilateral and contralateral hyperalgesia was evaluated using the Randall-Sellito pressure test. Heart rate changes were also recorded under general anesthesia. Then, the effects of a bupivacaine sciatic nerve block and subcutaneous injection of naloxone or ketamine were evaluated for Car-induced hyperalgesia. Data were analyzed using analysis of variance followed by unpaired Students t-test (significance P < 0.05). Before Car injection, no significant difference was observed in response to mechanical stimuli between the control and the deficiency groups (n = 114 in pooled data). Car injection induced significant ipsilateral and contralateral hyperalgesia in the control groups, whereas a significant analgesic effect appeared in the deficient groups on both the ipsilateral and contralateral hindpaws. This analgesic effect was confirmed by the electrocardiogram recording that showed a significant increase in heart rate in the control group after Car injection compared with the deficiency group that showed a decrease in heart rate under general anesthesia. Bupivacaine sciatic nerve block had no significant effect on hypoalgesia phenomena induced by polyamine deficiency. Naloxone administration had no effect in the control group but reversed the analgesic effect in the deficiency group. Ketamine administration induced a significant analgesic effect in the control group and partly reversed the analgesic effect in the deficiency group. In conclusion, a synthetic polyamine-deficient diet had a significant general analgesic effect on Car-induced mechanical hyperalgesia. The mechanism of analgesic action remains to be elucidated.

Diagnosit value of erythrocyte-free polyamines and histaminemia in malignant hepatic tumors and in liver cirrhosis

The present study tries to evaluate the diagnosit value in malignant hepatic tumors of polyamines, of which the relationship with cellular kinetics is known, and histamine, of which catabolism follows a similar pathway. One hundred and fifty six patients were studied: 53 with malignant liver tumors (27 primary, 26 metastatic) and 103 with non-tumoral liver diseases of which 65 were cirrhotic and 38 non-cirrhotic. Erythrocyte polyamines (spermidine and spermine) and histamine levels were assayed. The results indicate the following. 1. Polyamine levels were significantly increased (a) in cirrhotic patients, not only when compared with controls (p < 10−8), but also when compared with the non-cirrhotic patients (p < 10−7); (b) in primary malignant hepatic tumors (p < 10−3). 2. Histamine was significantly increased (a) in the non-tumoral liver diseases (p < 10−4), but with no difference between cirrhotic and non-cirrhotic patients; (b) in the secondary malignant tumor patients, histamine levels were lower than in primary tumor patients (p < 0.04). 3. There was no correlation, in all groups studied, between polyamine and histamine levels. These results suggest the following practical implications. 1. For non-tumor liver diseases, appreciably increased polyamine levels may represent a further argument favoring a cirrhotic condition. 2. In diagnosing hepatic scintigraphic defects, inbetween histamine and polyamines, are in favor of histamine synthesis. In the secondary malignant hepatic tumor group, histamine levels were low. sometimes considerably. Future studies, by estimating plasma diamine oxidase activity may he able to solve some of these questions. In conclusion, the evaluation of erythrocyte polyamine and histamine levels has two practical implications in hepatology. For non-tumor liver diseases, appreciably increased red blood cell polyamine levels may represent a further argument favoring a cirrhotic condition. In diagnosing hepatic scintigraphic defects, increased erythrocyte polyamine levels would suggest a primary malignant hepatic tumor; low histamine levels are more in favor of a secondary malignant hepatic process.

Differential recognition of free and covalently bound polyamines by the monoclonal anti-spermine antibody SPM8-2

The reactivity of an anti-spermine MAb (SPM8-2) toward polyamines either free or bound to a solid surface was investigated using equilibrium dialysis and ELISA methods. When polyamines were covalently linked to hydrophilized microtiter plates using carbodiimide, the MAb SPM8-2 reacted both with spermine and spermidine, with a higher affinity for the latter, but did not show any reactivity towards bound putrescine. In contrast, the MAb SPM8-2 reacted with all three polyamines bound to the microtiter plates with glutaraldehyde, with an affinity in the order: putrescine > spermidine > spermine. Equilibrium dialysis and competitive ELISA tests showed that the MAb SPM8-2 exhibited high affinity for free spermine and 50% and 5% cross-reactivity with free spermidine and putrescine respectively. The affinity of the MAb SPM8-2 for putrescine, spermidine and spermine appears to depend on whether the polyamine is free or bound. The antigenicity of the polyamines differs according to the nature of their link to the solid phase. These observations are discussed in the light of the structural modification produced by covalent binding of the polyamines. It is also concluded that when antibodies are used, due care has to be exercised in choosing the appropriate immunoassay for determining the specificity of antibodies directed against small haptens such as the polyamines.

Evolution of red blood cell polyamine levels in partially hepatectomized rat

Erythrocyte levels of polyamines, especially of spermidine are greatly elevated during the course of liver regeneration. In contrast to putrescine and spermine levels, from the tenth hour to the fourth week after partial hepatectomy, correlation has been observed between the elevation of liver and erythrocyte spermidine concentrations. Substituting drinking water with 2% alpha difluoromethylornithine (alpha-DFMO) commencing 48 hr prior to partial hepatectomy and continuing until death, though ineffective in inhibition of liver [3H]-thymidine incorporation, prevented the rise in hepatic putrescine concentrations (without modifying those of spermidine and spermine) and correlatively decreased red blood cell (RBC) spermidine levels. Thus, an excess of liver spermidine produced from an excess of newly synthetized putrescine could be released in blood and taken up by erythrocytes, especially as affinity of RBC for spermidine is at least 30 fold higher than that for putrescine. In vivo the spermidine half-life in RBC was estimated to be 2.5-3.0 hr, which could explain the elevation of erythrocyte and liver spermidine levels. The elevation of erythrocyte spermidine concentration is not correlated to that of the regenerating liver weight but dependent on the extent of partial hepatectomy. The elevation of erythrocyte spermidine concentrations, which appeared to be linked to the cellular proliferating activity, could contribute to determine intratumoral proliferation in cancerous patients.