Stressed Jerusalem artichoke tubers (Helianthus tuberosus L.) excrete a protein fraction with specific cytotoxicity on plant and animal tumour cell.

Wounds from Jerusalem artichoke (Helianthus tuberosus L.) tubers excrete bioactive metabolites from a variety of structural classes, including proteins. Here we describe a protein specifically active against tumour cells arising either from human, animal or plant tissues. The non-tumour animal cells or the plant callus cells are not sensitive to these excreta. The active product was only obtained after a wound-drought stress of plant tubers. The cytotoxicity varies according to the tumour cell type. For instance, some human tumour cell lines and especially the human mammary tumour cells MDA-MB-231 were shown to be very susceptible to the active product. The active agent is shown to contain an 18-kDa polypeptide with homology to a superoxide dismutase (SOD). A 28-kDa polypeptide, related to an alkaline phosphatase (AP), was shown to be tightly linked to this 18-kDa polypeptide. The excreted 28-kDa polypeptide also displayed a consensus sequence similar to the group of DING proteins, but with a smaller molecular weight. The superoxide dismutase polypeptide was shown to be involved in the antitumour activity, but the presence of smaller factors (MW<10 kDa), such as salicylic acid, can enhance this activity.

Analysis of secreted protease inhibitors after water stress in potato tubers.

Potato tubers (Solanum tuberosum) secrete two kinds of proteinase inhibitors after a water stress. The polypeptides have differing inhibitory activities but are Kunitz-type inhibitors based on amino-terminal sequences homologies. A proteolysis maturation type of a cell protease inhibitor was observed. They can constitute high MW complex, sometimes with another type of protein. The function of these protease inhibitors is discussed in relation to plant defence.

Quantification by affinity perfusion chromatography of phosphorylated BRCAl and BRCA2 proteins from tumor cells after lycopene treatment.

A new procedure for the quantification of phosphorylated BRCA1 (P-BRCA1) and BRCA2 (P-BRCA2) proteins in breast cell lines after different treatments was carried out. Cells were cultivated with [35S]-methionine and extracts subjected to three perfusion chromatographies. First heparin affinity chromatography purified cellular DNA-binding proteins. Subsequent specific immunoprecipitation of BRCA1 and BRCA2 proteins was performed with antibodies raised against BRCA1 or BRCA2. The immune complexes were isolated by protein A affinity chromatography. Phosphorylated BRCA1 or BRCA2 proteins were then purified with a Poros 20 AL column where anti-phosphothreonine and anti-phosphoserine antibodies were previously bound. The percentage of phosphorylated BRCA1 or BRCA2 proteins was calculated as follows: 100 x dpm of P-BRCA1 or P-BRCA2 eluted from the POROS 20AL column/total dpm eluted from POROS 20AL column. Treatment with 10 microM lycopene increased P-BRCA1 and P-BRCA2 in the breast tumor cell line MCF7 but not in MDA-MB-231 or MCF-10a, breast tumor or fibrocystic cell lines, respectively.

The effects of lycopene on the proliferation of human breast cells and BRCA1 and BRCA2 gene expression.

The purpose of this study was to demonstrate the effects of lycopene, the major tomato carotenoid, on the expression of the BRCA1 and BRCA2 genes in three breast tumour cell lines, MCF-7, HBL-100, MDA-MB-231 and the fibrocystic breast cell line MCF-10a. Flow cytometry analysis showed a G(1)/S phase cell cycle-arrest after treatment of the cells with 10 microM lycopene for 48 h. mRNA expression was studied by quantitative reverse transcription-polymerase chain reaction using the Taqman method. We observed an increase of BRCA1 and BRCA2 mRNA in the oestrogen receptor (ER)-positive cell lines (MCF-7 and HBL-100), and a decrease (MDA-MB-231) or no change (MCF-10a) in the ER-negative cell lines. BRCA1 and BRCA2 proteins were quantified by perfusion affinity chromatography. No variation in their expression was observed. These preliminary results on the effects of lycopene on the expression of BRCA1 and BRCA2 oncosuppressor genes in breast cancer may reflect cross-talk between the oestrogen and retinoic acid receptor (RAR) pathways.

In vitro and in vivo evaluations of THAM derived telomers bearing RGD and Ara-C for tumour neovasculature targeting.

As an approach to the development of specific drug delivery systems, a new class of low macromolecular carriers called 'telomers' endowed with an antitumour agent, such as arabinofuranosylcytosine (Ara-C), RGDSK peptidic sequences, as tumour targeting moieties, and tyrosine groups labelled with 125I atoms allowing the in vivo scintigraphic follow up, were synthesized. Their tumour targeting ability was assessed in vivo in mice bearing a murine B16 melanoma. The biological results showed that the presence of RGDSK sequences onto the macromolecules leads to the selective targeting and the accumulation of telomers within the vascularized zone of the tumour. Moreover, such compounds exhibited in vitro a better IC(50) (0.015 muM) than pure Ara-C and in vivo an oncostatic index higher than 160%.

Methionine dependency and cancer treatment.

Conventional chemotherapies have showed their limits, notably for patients with advanced cancer. New therapeutic strategies must be identified, and the metabolic abnormalities of cancer cells offer such opportunities. Many human cancer cell lines and primary tumors have absolute requirements for methionine, an essential amino acid. In contrast, normal cells are relatively resistant to exogenous methionine restriction. The biochemical mechanism for methionine dependency has been studied extensively, but the fundamental mechanism remains unclear. A number of investigators have attempted to exploit the methionine dependence of tumors for therapeutic effects in vivo. To reduce in vivo methionine in plasma and tumours, dietary and pharmacological treatments have been used. Methionine-free diet or methionine-deprived total parenteral nutrition causes regression of a variety of animal tumours. Alternatively, methionine depletion was achieved by the use of methioninase. This enzyme specifically degrades methionine and inhibits tumour growth in preclinical models. Because of potential toxicity and quality of life problems, prolonged methionine restriction with diet or with methioninase is not suitable for clinical use. Methionine restriction may find greater application in association with various chemotherapeutic agents. Several preclinical studies have demonstrated synergy between methionine restriction and various cytotoxic chemotherapy drugs. The experimental results accumulated during the last three decades suggest that methionine restriction can become an additional cancer therapeutic strategy, notably in association with chemotherapy.

Inhibition of O6-alkylguanine-DNA alkyltransferase by O6-benzyl-N2-acetylguanosine increases chloroethylnitrosourea-induced apoptosis in Mer+ human melanoma cells.

The exposure of cells to -benzyl- 2-acetylguanosine (BNAG) and several guanine derivatives is known to reduce -alkylguanine-DNA alkyltransferase (AGAT) activity and to decrease the resistance of methyl enzyme repair positive (Mer ) cells to chloroethylnitrosoureas (CENUs) and. We evaluated the influence of AGAT activity inhibition by BNAG on the ability of two CENUs, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 3-(2-chloroethyl)-1-(2-methylsulphonyl)ethyl-3-nitrosourea (cystemustine), to induce an apoptotic response in two melanoma cell lines, M3 Dau (Mer ) and IPC 227F (Mer ). The apoptotic morphology of cells was assessed by microscopy after Wright-Giemsa or Hoechst 33342 staining of cells, and DNA internucleosomal cleavage was demonstrated by the ladder-like pattern of DNA separated by agarose gel electrophoresis. The concentration-dependent number of apoptotic cells assessed using a terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick-end labelling (TUNEL) assay 72 h after BCNU or cystemustine treatment (0-400 microM for 2 h) was increased by prior AGAT depletion with BNAG pretreatment (300 microM for 4 h) in Mer cells. These results suggest that the DNA lesions on the position of guanine are a key event in inducing an apoptotic response in melanoma cells. We also observed that cystemustine was a more potent inducer of apoptosis than BCNU, and that the synergism with BNAG was more potent with cystemustine than with BCNU. These results suggest that the nature of the CENUs associated with an AGAT inhibitor is a determinant factor in forecasting the clinical efficacy of the association, especially in melanoma.

Pharmacokinetic study of cystemustine, administered on a weekly schedule in cancer patients.

BACKGROUND: Cystemustine is a chloroethylnitrosourea mostly active in humans against glioma and melanoma. The present report describes the results of a new phase I trial with cystemustine administered on a weekly schedule. The pharmacokinetic and pharmacodynamic properties of cystemustine were investigated. PATIENTS AND METHODS: Forty-three patients entered this study. Cystemustine was administered at dose levels ranging from 30 to 60 mg/m2. The drug was given on days 1, 8, 15 and 22, followed by a 4-week rest period. RESULTS: Thrombocytopenia was the dose-limiting toxicity and appeared to be reversible, but probably cumulative. This toxicity appeared dose-related, both in frequency and severity. The maximum tolerated dose was 60 mg/m2. Nonhematological toxicity was generally mild. Three partial responses were observed at dose levels of 50 and 60 mg/m2. Pharmacokinetics analysis showed mono- or biphasic cystemustine blood disposition with a mean a half-life of 4 min and mean terminal half-life of 49 min. CONCLUSIONS: There was a clear linear relationship between the area under the blood drug concentration-time curve (AUC) and the dose of cystemustine (P < 0.001). There was also a significant relationship between the AUC and the toxic effects of cystemustine on platelets, granulocytes and leukocytes (P < 0.001). A reasonable starting dose for phase II studies is 40 mg/m2, with dose escalation based on blood cell counts.

Determination of BRCA2 oncosuppressor protein expression in human mammary cells by affinity perfusion high-performance chromatography.

In this work, we report a method for the determination of BRCA2 oncosuppressor protein in human mammary cells by affinity perfusion chromatography. This method involves labeling proteins with [(35)S]-methionine. The isolation and purification of DNA-binding proteins was performed by affinity chromatography on Heparin POROS 20HE. BRCA2 proteins, known to act in the transcriptional control and in DNA repair activity, are included in the DNA-binding proteins. Specific immunoprecipitation was performed with anti-BRCA2 antibodies, and the immune complex [(35)S-BRCA2 proteins/anti-BRCA2 antibodies] was isolated by affinity chromatography on a Protein A POROS column. This procedure allows the determination of the percentage of BRCA2 among the DNA-binding proteins and the quantitation of the difference of expression of BRCA2 oncosuppressor protein in breast carcinoma cells and in normal breast cells treated or untreated with phytoestrogens, such as daidzein or genistein.

Joint scintigraphy in rabbits with 99mtc-N-[3-(triethylammonio)propyl]-15ane-N5, a new radiodiagnostic agent for articular cartilage imaging.

UNLABELLED: The aim of this study was to investigate joint scintigraphy in rabbits with 99mTc-N-[3-(triethylammonio)propyl]-15ane-N5 (NTP 15-5), a new radiopharmaceutical that specifically localizes in cartilaginous tissues. METHODS: Scans obtained after intravenous injection of the 99mTc-labeled compound in normal and arthropathy-induced rabbits were compared with those of the bone-imaging agent 99mTc-methylene diphosphonate (99mTc-MDP). RESULTS: The radioactive uptake of 99mTc-NTP 15-5 was detected in cartilaginous tissues 5 min after injection and was stable for 2 h. The uptake intensity was related to age and joint disease severity, and cartilage alterations not revealed by radiography induced a significant decrease of radiotracer uptake. On the other hand, imaging performed with 99mTc-MDP did not reveal the early changes in arthrosis but was more specific for bone remodeling in advanced stages of diseases or in inflammatory processes. CONCLUSION: Our results indicate that 99mTc-NTP 15-5 could be a good tracer for human arthrosic and arthritic cartilage detection, especially for the early diagnosis of joint diseases.

Cyclosporine A inhibition of prolactin-dependent up-regulation of BRCA1 protein expression in human breast cell lines.

BACKGROUND: Previously, we reported experimental evidence that BRCA1, breast and ovarian cancer susceptibility gene is up-regulated in response to Prolactin stimulation. In this work, we studied the effects of Cyclosporine A and the competition with Prolactin on BRCA1 protein expression in vitro. METHODS: The expression of BRCA1 was monitored in a human breast cancer cell line (MCF7) by comparison with a normal breast epithelial one (MCF10a) treated with Cyclosporine A and ovine Prolactin. The amount of BRCA1 protein expression was quantified using a strategy of two successive affinity perfusion chromatographies. RESULTS AND CONCLUSION: We showed that Prolactin in presence of Cyclosporine A has no effect on BRCA1 protein expression in human breast cell lines. This emphasized the hypothesis that BRCA1 may be stimulated by Prolactin.

Application to a cartilage targeting strategy: synthesis and in vivo biodistribution of (14)C-labeled quaternary ammonium-glucosamine conjugates.

As part of a cartilage targeting program based on the affinity of the quaternary ammonium (QA) moiety for cartilage, QA derivatives of D-glucosamine (DG), an antirheumatic drug exhibiting a natural tropism for cartilaginous tissues, were designed and evaluated by pharmacokinetic studies. Two QA-DG conjugates were synthesized and labeled with (14)C by cross-linking the QA entity (trimethylammonium or pyridinium) to [(14)C]DG via an amide bond in a two-step procedure. After intravenous injection to male Sprague-Dawley rats, the two (14)C-labeled conjugates exhibited similar pharmacokinetic profiles, but their behavior clearly differed from that of unconjugated DG in several ways. (i) The tissue distribution for the conjugates was more restricted, with a decreased radioactivity level for whole tissues except for kidney, cartilage, and skin. (ii) The radioactivity concentrated more rapidly and strongly in cartilage for the conjugates than for DG for the short times after injection; on the other hand, 1 h after administration, the radioactivity level in cartilage was higher for DG, this result being consistent with the tropism already observed for this compound. (iii) Both conjugates were eliminated predominantly by the urinary route (85%); the radioactivity level in urine for DG was lower (45% of the injected dose), and significant (14)CO(2) was found in expired air, indicating metabolization and utilization of DG for energy-consuming processes. (iv) Blood and plasma kinetics studies displayed an enterohepatic cycle for DG, whereas for the QA conjugates, a rapid disappearance was observed. (v) HPLC analyses of plasma and urine indicated a low degree of metabolization for the conjugates, most of the radioactivity recovered in urine and plasma corresponding to the unchanged molecule. This study demonstrates that the introduction of the QA moiety on DG modifies its biodistribution and lends it a greater specificity for cartilage, at least for short times after injection. These findings justify further work on QA derivatives of other antirheumatic agents.

Disposition in rats of N-pyridinium-propyl-cyclam, N-triethylammonium-propyl-cyclam, and N-[Triethylammonium]-3-propyl-[15]ane-N5, potential cartilage imaging agents.

Quaternary ammonium compounds are known to highly concentrate in articular cartilages after i.v. administration. This property was used to synthesize new potential radiodiagnostic agents for joint imaging. Pharmacokinetic study was performed in rats for three new compounds: N-pyridinium-propyl-cyclam (NPPC), N-triethylammonium-propyl-cyclam (NTPC), and N-[triethylammonium]-3-propyl-[15]ane-N5 (NTP 15-5). After i.v. administration, [(3)H]NPPC and [(3)H]NTPC highly and rapidly concentrated in articular cartilage, this uptake being followed by a single exponential decrease with half-lives of, respectively, 75 and 82 min. Except cartilage, only the kidney was highly labeled. After complexation of (99m)Tc by NPPC, NTPC, and NTP 15-5, only (99m)Tc-NTP 15-5 exhibited a high affinity for cartilage. On the other hand, the pharmacokinetic behavior of (99m)Tc-NTPC and (99m)Tc-NPPC was very different from those of their (3)H-labeled analogs. Concentration in cartilaginous tissues was strongly diminished, and liver and bone were highly labeled. For all labeled species, the major route of excretion was urine, and HPLC analysis showed that [(3)H]NTPC and [(3)H]NPPC were excreted under their unchanged form. On the other hand, no (99m)Tc-NTPC and (99m)Tc-NPPC were found in the urine, the radioactivity being mainly due to free technetium, contrary to (99m)Tc-NTP 15-5, which was excreted in the urine under the complexed form. These data can explain the striking differences observed between the three (99m)Tc-labeled molecules, the lack of concentration of (99m)Tc-NTPC, and (99m)Tc-NPPC in cartilages in comparison with their (3)H-labeled analogs due to an instability in vivo of these technetiated complexes.

New quaternary ammonium oxicam derivatives targeted toward cartilage: synthesis, pharmacokinetic studies, and antiinflammatory potency.

Analogues of nonsteroidal antiinflammatory drugs (NSAIDs) oxicams, in which the active group was linked to a quaternary ammonium function [(4-hydroxy-2-methyl-2H-1,2-benzothiazine-1, 1-dioxide-3-carboxamido)2-methylpyridinium iodide or piroxicam-N(+) and [3-(4-hydroxy-2-methyl-2H-1,2-benzothiazine-1, 1-dioxide-3-carboxamido)propyl]trimethylammonium iodide or propoxicam-N(+)] were synthesized. Compounds were labeled with tritium for piroxicam-N(+) and carbon-14 for propoxicam-N(+). Pharmacokinetic studies conducted on rats showed that these molecules were able to highly concentrate in joint cartilages but their bioavailability by the oral way was low. Only propoxicam-N(+) exhibited a sufficient water solubility to be administered intravenously. This molecule was able to restore proteoglycans biosynthesis in cultured articular chondrocytes treated with Interleukin-1beta with an efficiency identical to that of indomethacin. These results suggest that the functionalization of oxicam derivatives by a quaternary ammonium group greatly increases their affinity toward articular cartilage without eliminating their pharmacological activity. New drugs synthesized according to this scheme could be useful to obtain a significant decrease of the efficient administered dose and consequently an attenuation of adverse effects such as digestive toxicity.

Synthesis and surface-active properties of glycosyl carbamates and thioureas.

Several amphiphilic glycosyl carbamates, glycosyl thiocarbamates and glycosylthioureas were prepared by addition of the anomeric hydroxyl group of acetylated glycosyl derivatives to alkyl isocyanates, or by reaction of glycosyl isothiocyanates with alcohols or amines. The solubility, critical micelle concentrations and detergent efficiency for the extraction of proteins of these compounds were evaluated and compared.

Prolactin-dependent up-regulation of BRCA1 expression in human breast cancer cell lines.

We report experimental evidence that BRCA1, a breast and ovarian cancer susceptibility gene, is up-regulated in response to prolactin (PRL) stimulation. Expression of the BRCA1 gene was monitored in 2 human breast cancer cell lines (MCF-7 and T-47D) and in the normal mammary epithelial cell line MCF10a. Using competitive RT-PCR, we have shown that PRL induced an increase in BRCA1 mRNA level in MCF-7 and T-47D cell lines at a dose resulting in the maximal enhancement of cell proliferation. The up-regulation was 12-fold in MCF-7 cells and 2-fold in T-47D cells. No increase in BRCA1 mRNA level was observed in the MCF10a cell line. The level of BRCA1 protein was quantified using an affinity chromatography strategy. At the protein level, PRL treatment induced a 4-fold increase of BRCA1 protein expression in MCF-7 and a 6-fold increase in T-47D cells, whereas BRCA1 protein expression was not affected by PRL in MCF10a.

Quantification of BRCA1 protein in sporadic breast carcinoma with or without loss of heterozygosity of the BRCA1 gene.

In sporadic breast cancer, no mutations of the BRCA1 gene have been reported so far, whereas BRCA1 mRNA is markedly decreased in invasive breast cancer. To elucidate the contribution of the BRCA1 gene in sporadic breast cancer, we quantified the BRCA1 protein, using [125I] labeling of whole-cell proteins, lentil-lectin affinity chromatography, immunoprecipitation by anti-BRCA1 antibodies (C-20, D-20, I-20 and K-18), purification of the immune complex by protein A affinity chromatography and chromato-focusing. As loss of 1 allele may lead to a decreased expression of the gene, 10 tumors were previously checked for loss of heterozygosity (LOH) of the BRCA1 gene, using 3 intragenic microsatellite markers. Our results indicated that the BRCA1 gene product was decreased in the 4 tumors with LOH compared with matched normal breast tissues. Reduced amounts of BRCA1 protein were also detected in 3 of 6 tumors without LOH. Our quantitative method allowed us to demonstrate that the BRCA1 protein level was decreased in sporadic invasive breast carcinomas with or without LOH of the BRCA1 gene, implying multiple mechanisms of BRCA1 expression down-regulation in these tumors. Our data suggest that the amount of BRCA1 protein present may play an important role in human sporadic breast carcinoma.

Isolation, purification and quantification of BRCA1 protein from tumour cells by affinity perfusion chromatography.

A new procedure for the isolation, purification and quantification of the product of the oncosuppressor gene brca1 in breast tissues, was carried out. It involves internal cell protein [35S]methionine labelling followed by two perfusion chromatographies. The first one is heparin affinity chromatography, to purify all of the cell DNA-binding proteins. A subsequent specific immunoprecipitation of BRCA1 protein was performed with an antibody raised against BRCA1. The immune complex was isolated using the second chromatographic step, Protein A affinity chromatography. The amount of BRCA1 expressed by cells was expressed as a ratio, in percent, calculated as follows: 100x amount of labelled DNA-binding proteins (dpm) that bound specifically to the anti-BRCA1 polyclonal antibodies (K-18)/amount of whole labelled DNA-binding protein (dpm) purified on a heparin column. Applications to MCF7 and T-47D human breast tumour cell lines, which were treated or not using 2 mM sodium butyrate demonstrated an increase in BRCA1 protein expression.