High performance liquid chromatographic determination of thalidomide in patients affected by hepatocellular carcinoma

The present study developed a validate and precise reversed-phase high performance liquid chromatography (HPLC) method for the determination of thalidomide (T) in plasma, to quantify T in patients affected by hepatocellular carcinoma. Twelve male subjects aging from 62 to 82 years and weighting 66-88kg, were orally administered with single dose of T (200mg/BW). Two ml of stabilizer-solution (CH3OH/CH3CN, 1/1 (v/v)+CH3COOH 2%) were added to 1ml of human plasma and stoked to -80 degrees C until analyses. This moisture (1.38microl) was added with 20microl of CF3COOH and 100microl of phthalimide (IS) 1.75microg/ml, vortexed and centrifuged. Surnatant (800microl) was dried under vacuum at room temperature, added with 50microl of appropriate solution and injected onto HPLC. T and IS were detected at UV wavelength of 220nm with a run time of 10min. Mobile phase was 10mM pH 5.5NH4+CH3COO-/CH3CN, 75/25 (v/v) buffer at flow rate of 1.5ml/min. Inter-day and intra-day variation coefficient was <10% with an error of accuracy <10%. The present detection method was able to quantify T to every withdrawal time period (LOD 0.05microg/ml). The IS used in the present study had the same wavelength maximum absorption of T, differently from early UV detection methods reported in literature where phenacetin was used. Pharmacokinetic parameters belonging from the present study are not significantly different from those calculated in previously studies performed in human health subjects and patients affected by other pathology.

Metabolically labile cannabinoid esters: A ‘soft drug’ approach for the development of cannabinoid-based therapeutic drugs

Biphenylic ester derivatives, designed by using a 'soft-drug' approach, proved to possess good binding properties toward cannabinoid CB(1) and CB(2) receptors and, at the same time, their metabolically labile ester portion would promote a rapid systemic inactivation. This may constitute a possible solution to the psychotropic side effects encountered when cannabinoids are therapeutically employed as local analgesic or antiglaucoma agents.

Short-term effects of 3,4-methylen-dioxy-metamphetamine (MDMA) on 5-HT(1A) receptors in the rat hippocampus

The first effects of 3,4-methylen-dioxy-metamphetamine (MDMA, "ecstasy"), on serotonin 1A (5-HT(1A)) receptors in rat hippocampus were determined by means of [(3)H]-8-hydroxy-dipropylamino-tetralin ([(3)H]-8-OH-DPAT) and 5'guanosine-(gamma-[(35)S]-thio)triphosphate ([(35)S]-GTPgammaS) binding as well as inhibition of forskolin (FK)-stimulated adenylyl cyclase (AC) activity. The study was completed by [(35)S]-GTPgammaS functional autoradiography experiments carried out in frontal sections of rat brain, including the hippocampal region. Results showed that MDMA was either able to displace [(3)H]-8-OH-DPAT binding (K(i) congruent with 500 nM) or to reduce the number of specific sites (B(max)) without affecting K(d). The drug also failed to change the [(35)S]-GTPgammaS binding or to inhibit AC velocity, underlying its behavior as a non-competitive 5-HT(1A) receptor antagonist. Further, MDMA (1 or 100 microM), partially antagonized either [(35)S]-GTPgammaS binding stimulation of the agonists 5CT and 8-OH-DPAT or the AC inhibition induced by 5CT and DP-5CT. However, in contrast to binding studies, in AC assays the amphetamine displayed an effect also on EC(50), always being less potent than the reference antagonist WAY100,635. In functional autoradiography, MDMA behaved either as a partial 5-HT(1A) antagonist in limbic areas or, added alone, as an agonist, increasing the coupling signal presumably through 5-HT release from synapses. Interestingly, the selective 5-HT re-uptake inhibitor (SSRI) fluoxetine had no effect on MDMA [(35)S]-GTPgammaS binding activation. This latter finding indicates that the amphetamine can release 5-HT via alternative mechanisms to 5-HT transporter binding, probably via membrane synaptic receptors or vesicular transporters. The release of other transmitters is not excluded. Therefore, our results encourage at extending the study of MDMA biochemical profiles, in the attempt to elucidate those amphetamine-induced pathways with a potential for neurotoxicity or psycho-stimulant activity.

Synthesis of stable analogues of geranylgeranyl diphosphate possessing a (Z,E,E)-geranylgeranyl side chain, docking analysis, and biological assays for prenyl protein transferase inhibition

Herein, we report the synthesis of novel stable analogues of geranylgeranyl diphosphate (GGPP), in which the "natural" all-trans geranylgeranyl portion has been replaced by a (Z,E,E)-geranylgeranyl chain. The change in configuration and consequent change in the relative position of the polar portion with the lipophilic side chain did not improve the properties of the E,E,E analogues in their inhibition of geranylgeranyl protein transferase I (GGTase I). However, a significant level of GGTase I inhibition and selectivity for GGTase I over farnesyl transferase (FTase) was maintained the unsubstituted phosphonoacetamidoxy derivative 4 a. This has shed light on the relative importance of the configuration at the C2=C3 double bond among GGPP derivatives. Moreover, the biological activities of all the compounds reported herein, in particular the preferential FTase inhibitory activity shown by compound 6, were in good agreement with the results of docking analysis.

Use of Capillary Electrophoresis and Poly(ethylene Oxide) as the Coating Agent for the Determination of Substances Related to Heroin Addiction and Treatment

The purpose of this study was to identify and quantify morphine, codeine, methadone, and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine using capillary electrophoresis in urine specimens. Adequate peak separation was achieved using nearly neutral pH phosphate buffer and poly(ethylene oxide) as the coating agent. This dynamic coating of the inner surface of the capillary was obtained by rinsing with a solution containing this compound. The electroosmotic flow and the interactions between analytes and the capillary wall surface were reduced, while resolution and reproducibility were thus improved. Detection limits were appropriate for usual analytical requirements in forensic laboratories.

Synthesis of Anthranylaldoxime Derivatives as Estrogen Receptor Ligands and Computational Prediction of Binding Modes

N-Me-anthranylaldoximes possess a hydrogen-bonded pseudocyclic A' ring in place of the typical phenolic A-ring that is characteristic of most estrogen receptor (ER) ligands. We have investigated the role played by substituents introduced into either one or both of the peripheral 3- and 4-phenyl rings in modulating ER binding affinity. An efficient synthetic strategy was employed for the preparation of differentially substituted 3- and 4-aryl derivatives that involved exploiting the different reactivity of bromo- versus chloro-aryl groups in palladium-catalyzed cross-couplings. The binding data showed that ERalpha affinity could be improved by a single p-OH group in the 4-phenyl ring, whereas the same substitution on the 3-phenyl ring caused a dramatic reduction of ERbeta affinity. The most ERalpha-selective compound was the one with two p-OH groups on both phenyl substituents. To rationalize these results, ligand docking followed by molecular mechanics Poisson-Boltzmann/surface area (MM-PBSA) studies were carried out. These analyses suggested a molecular basis for the interaction of these compounds with the ERs and enabled the development of models able to predict the mode of ligand binding.

Variously substituted (phosphonoacetamido)oxy analogues of geranylgeranyl diphosphate (GGdP) as GGdP-transferase (GGTase) inhibitors and antiproliferative agents

Aberrant signalling through the pathways of small GTP-binding proteins, belonging to the Ras superfamily (Ras, Rho, Rac, Cdc42 etc.), occurs in several types of cancer, where mutated Ras accumulates in its GTP-bound active form and causes uncontrolled cell proliferation. For these reasons, molecules able to target the Ras pathway in any of its stages are potentially useful in anti-cancer therapies. Inhibition of farnesyl-protein transferase (FTase), the enzyme that post-translationally activates Ras, has been pursued for the obvious role of the Ras oncoprotein in human malignancies. It was later found that some mutated forms of Ras (K- and N-Ras) can also be geranylgeranylated by geranylgeranyl-protein transferase (GGTase) when FTase is blocked, circumventing the antiproliferative effects of FTase inhibitors. Therefore, a new task has been the search for new GGTase inhibitors, which can also interfere on cell proliferation by blocking the isoprenylation of other Ras superfamily proteins (i.e. Rho, Rac, Cdc42) involved in the regulation of cell cycle progression. We have recently described a series of phosphonoacetamido- and phosphonoacetamidoxy-stable analogues of geranylgeranyl-diphosphate (GGdP) possessing good GGTase inhibitory properties and, some of them, also remarkable GGTase/FTase selectivity levels. We have now extended this series to a larger number of variously substituted phosphonoacetamidoxy-analogues of GGdP in order to establish the effect on GGTase inhibitory activity and selectivity due to the presence of different substituents in the polar portion of these GGdP mimics. We have also measured the cytotoxicity of these compounds on tumour cell lines with the aim of evaluating their potential anti-proliferative effects.

New NO-Releasing Pharmacodynamic Hybrids of Losartan and Its Active Metabolite: Design, Synthesis, and Biopharmacological Properties

In a preliminary work, we reported two NO-sartans, possessing the characteristics of an AT(1) antagonist and a "slow NO donor", obtained by adding NO-donor side chains to losartan 1. The NO release from an NO-sartan should be modulated in order to strengthen the antihypertensive activity of the native drug and to ensure additional effects, such as the antiplatelet and anti-ischemic ones. To obtain a collection of prototypical NO-sartans, showing different rates of NO release, new NO-donor moieties have been linked to 1 or its active metabolite 2 (EXP 3174). Almost all the synthesized compounds exhibited both AT(1)-antagonist and NO-mediated vasorelaxing properties, with a wide range of NO-releasing rates. Further pharmacological investigation on compound 4a showed that it possessed antihypertensive and cardiac antihypertrophic effects similar to those of the reference AT(1)-blocking or ACE-inhibiting drugs. Furthermore, the additional anti-ischemic cardio-protective properties and antiplatelet effects of 4a have been preliminarily investigated.

N6‐isopentenyladenosine arrests tumor cell proliferation by inhibiting farnesyl diphosphate synthase and protein prenylation

The physiological effects of a variety of N6-substituted adenine and adenosine derivatives called cytokinins have been documented in plants, but information on their occurrence and function in other biological system is limited. Here we investigated the anti-proliferative effect of N6-isopentenyladenosine (i6A), an adenosine and isoprenoid derivative, in a thyroid cell system, FRTL-5 wild-type, and K-ras transformed KiMol cells. Addition of i6A to FRTL-5 cells caused a dose-dependent arrest of the G0-G1 cell phase transition associated with a reduction of cells in the S phase that was much more evident in KiMol cells. I6A arrested tumor cell proliferation by inhibiting farnesyl diphosphate synthase (FPPS) and protein prenylation. Indeed the addition of farnesol reversed these effects and i6A affected protein prenylation, in particular lamin B processing. I6A effect was not mediated by the adenosine receptor but was due to a direct modulation of FPPS enzyme activity as a result of its uptake inside the cells. I6A inhibited FPPS activity more efficaciously in KiMol cells than in normal FRTL-5. Moreover, the i6A anti-proliferative effect was evaluated in vivo in a nude mouse xenograft model, where KiMol cells were implanted subcutaneously. Mice treated with i6A showed a drastic reduction in tumor volume. Our findings indicate that this isoprenoid end product might be used for antineoplastic therapy, an application emulating that of the lovastatin and/or farnesyl-transferase inhibitors

Phosphonomethylphosphorylmethyl(oxy)-analogues of geranylgeranyl diphosphate as stable and selective geranylgeranyl protein transferase inhibitors

The diphosphate moiety of geranylgeranyldiphosphate (GGdP) was replaced with metabolically and hydrolytically stable analogous polar portions, in an attempt to obtain new geranylgeranyltransferase (GGTase) inhibitors, which could also be selective over congener enzyme farnesyltransferase (FTase). In particular, the phosphonomethylphosphorylmethoxy derivative showed the highest inhibition potency, accompanied by a satisfactory GGTase/FTase selectivity.

Synthesis of a resveratrol analogue with high ceramide-mediated proapoptotic activity on human breast cancer cells

Resveratrol, a natural product with a stilbene structure, exerts profound proapoptotic activity in human cancer cells, by triggering the accumulation of ceramide, a bioactive sphingolipid. We studied the biological effects of seven methoxylated and/or naphthalene-based resveratrol analogues and compared these compounds with resveratrol with the objective to identify an analogue with higher ceramide-mediated proapoptotic activity relative to resveratrol. Here we show that the compound with three hydroxyls and a naphthalene ring is the most effective in triggering apoptosis coupled to the induction of endogenous ceramide in human cancer cells.

N-i-Propoxy-N-biphenylsulfonylaminobutylhydroxamic acids as potent and selective inhibitors of MMP-2 and MT1-MMP

Structural manipulation of the pharmacophoric model of type A selective MMP inhibitors (MMPi), obtained by the insertion of some alkyl substituents R2 possessing an appropriate geometry, steric bulkiness and lipophilicity, is able to improve potency, in the subnanomolar range on MMP-2, and to give a good MMP inhibition on MMP-14 (MT1-MMP) in the designed MMPi of type C, while maintaining a good MMP-1/MMP-2 selectivity profile. The simultaneous inhibition of these two enzymes yields type C compounds, which are potent antiangiogenic agents, able to block a chemoinvasion model on HUVEC cells in the micromolar range.

Stable propylphosphonic acid analogues of geranylgeranyl diphosphate possessing inhibitory activity on geranylgeranyl protein transferase

Stable analogues of geranylgeranyl diphosphate, possessing 3-(phosphono)propionamido moieties in the place of the metabolically unstable diphosphate portion, were prepared and submitted to prenyltransferase (GGTase and FTase) inhibition assays. In one case, an excellent GGTase inhibitory activity was obtained (IC(50) = 39 nM), accompanied by a certain degree of GGTase vs. FTase selectivity.

Synthesis and antimicrobial activity of new 7β-(benzo[a]dihydrocarbazolyloxyacetyl)-substituted cephalosporins

Selected 7beta-(benzo[a]dihydrocarbazolyloxyacetyl)-substituted cephalosporins (1a-e) were synthesised and tested for their antimicrobial activity against Gram-positive and Gram-negative clinical pathogens. All compounds synthesised (1a-e) showed an in vitro antimicrobial activity similar to that of ceftriaxone and cefpirome against the Gram-positive bacteria, and superior to that of penicillin and cefaclor against pen-R Staphylococcus aureus species. Like all beta-lactam agents, compounds 1a-e were in an inactive Minimum Inhibitory Concentration (MIC > 32 microg/ml) against methicillin-resistant S. aureus species. Furthermore, as expected, no cross-resistance was observed against the erythromycin-resistant Staphylococcus pyogenes strain. Finally, it is worth underlining that compounds 1a and 1e showed a similar activity to that of ceftriaxone and superior to cefaclor against penicillin-resistant Streptococcus pneumoniae isolates, a key respiratory tract infection (RTI) causing pathogen difficult to treat with currently marketed antibiotics.

Stable analogues of geranylgeranyl diphosphate possessing improved geranylgeranyl versus farnesyl protein transferase inhibitory selectivity

Phosphonoacetamido(oxy) groups have proven to be good mimics of the diphosphate portion in geranylgeranyl protein transferase I (GGTase I) inhibitors. The introduction of small alkyl groups (Me, Et) into the diphosphate mimic moiety caused a further decrease in collateral farnesyl protein transferase (FTase) inhibitory activity, thereby improving GGTase I over FTase selectivity.

Diaryl-substituted salicyl- and anthranyl-ketoximes as potential estrogen receptor ligands

3,4-diphenylsalicylaldoxime and 3,4-diphenylanthranylaldoxime derivatives, containing small groups (methyl or ethyl) on the imine carbon atom, were synthesized and submitted to biological assays. Binding tests performed on uterine cytosol estrogen receptor (ER) preparation and on purified full-length human ERalpha and ERbeta, showed that the newly synthesised compounds exhibit considerably lower binding affinities with respect to reference non-substituted 3,4-salicylaldoxime.

New N-arylsulfonyl-N-alkoxyaminoacetohydroxamic acids as selective inhibitors of gelatinase A (MMP-2)

New N-arylsulfonyl-substituted alkoxyaminoaceto hydroxamic acid derivatives of types 8 and 10 designed as oxa-analogues of known sulfonamide-based MMPi of types 2 and 7 were synthesized and tested for their inhibitory activities on some matrix metalloproteinases. The combination of a biphenylsulfonamide group with oxyamino oxygen in the pharmacophoric central skeleton of sulfonamide-based MMPi obtained in the new sulfonamides 10 seems to be able to give selectivity for MMP-2 over MMP-1. The most potent derivative of this type, 10a, shows similar anti-invasive properties to the analogue reference drug CGS27023A, 2, in an in vitro model of invasion on matrigel, carried out on cellular lines of fibrosarcoma HT1080 (tumoural cells over-expressing MMP-2 and MMP-9).

Efficient application of monolithic silica column to determination of illicit heroin street sample by HPLC

In this paper, an HPLC method is proposed for a routine, rapid and simple analysis of heroin samples confiscated from the illicit market, based on a new type of packing for HPLC columns (monolithic silica). Acetonitrile and pH 3.5 phosphate buffer solution were used under both isocratic and gradient conditions. Under our analytical conditions, all the components of a typical mixture of an illicit heroin sample proved to be fully separated into well-resolved peaks in 7 min. Analytical linearity and accuracy of the method were also studied for all analytes using tetracaine hydrochloride as the internal standard.

Synthesis of aniline-type analogues of farnesyl diphosphate and their biological assays for prenyl protein transferase inhibitory activity

Stable analogues of farnesyl diphosphate, possessing an aniline-type portion in the prenyl-mimic moiety and phosphonoacetamido(oxy) groups in the place of the metabolically unstable diphosphate unit, were synthesised and submitted to biological assays. The enzyme inhibition tests performed on FTase and GGTase I show that the newly synthesised compounds based on a combination of the aniline-containing portions with (phosphonoacetamido)oxy groups do not afford potent inhibitors.

Novel estrogen receptor ligands based on an anthranylaldoxime structure: role of the phenol-type pseudocycle in the binding process

The 3,4-diphenylsalicylaldoxime system 1 is an estrogen receptor (ER) ligand of unusual structure, having a hydrogen-bonded pseudocyclic A'-ring in place of the paradigmatic phenolic A-ring that is characteristic of most estrogens. We have investigated the role played by the pseudocycle A' in binding to the ER by preparing 3,4-diphenylbenzaldoxime (4), a compound that completely lacks this ring but still preserves all of the other features of the original molecule 1, as well as a series of 3,4-diphenylanthranylaldoximes (5a-c) in which the nature of the heteroatom participating in the formation of pseudoring A' has been changed from an oxygen (1) to a nitrogen that is either unsubstituted (5a) or substituted with small alkyl groups (a methyl in 5b, or an ethyl in 5c). The importance of hydrogen-bonded pseudocycle A' in the binding process was confirmed by the fact that benzaldoxime 4 showed a greatly reduced binding affinity compared to salicylaldoxime 1. Moreover, the binding affinity improved considerably when the A'-ring contained either an unsubstituted nitrogen (5a) or an N-Me group (5b). On the other hand, the N-Et-substituted anthranyl derivative 5c showed a marked drop in binding affinity. Molecular modeling docking studies on ERalpha confirmed that compounds 5a and 5b fit nicely in the ligand binding pocket, with an especially comfortable fit for the N-Me group of 5b in a small hydrophobic pocket surrounded by nonpolar residues. The limited size of this pocket does not allow accommodation of N-substituents larger than a methyl group, which is consistent with the low binding affinity of the N-Et compound 5c.

Glycosaminoglycans provide a binding site for thyroglobulin in orbital tissues of patients with thyroid-associated ophthalmopathy

The presence of thyroglobulin (Tg) in orbital tissues of patients with thyroid-associated ophthalmopathy (TAO) supports a role of Tg in TAO pathogenesis. To search for Tg-binding sites in orbital tissues, because Tg is a heparin-binding protein, we investigated its binding to glycosaminoglycans (GAGs) that are abundant in orbital tissues: chondroitin sulfate B (CSB) and C (CSC) and hyaluronic acid (HA). Both in solid phase and solution phase assays purified human Tg bound to GAGs. In solid-phase assays, binding was increased by coincubation with heparin or GAGs in solution, or with an antibody against a Tg heparin-binding sequence (Arg2489-Glu2503), possibly suggesting crosslinking of Tg molecules induced by GAGs or by the presumably bivalent antibody. Orbital tissue extracts from TAO patients that contained Tg were subjected to high-salt treatment, which resulted in separation of Tg from GAGs, as observed by column chromatography. After separation from GAGs, the Tg in orbital tissue extracts acquired the ability to bind to immobilized CSB, and heparin enhanced binding, resembling the findings with purified human Tg. Therefore, we conclude that GAGs provide binding sites for Tg in orbital tissues, which may explain the presence of Tg in orbital tissues of patients with TAO.

Involvement of prenylated proteins in calcium signaling induced by LTD4 in differentiated U937 cells

We investigated signal transduction pathways for LTD4 in the human promonocytic cell line U937 known, upon differentiation, to express CysLT1 receptors. We confirmed the presence of high-affinity binding sites for 3H-LTD4, which, in functional studies, displayed the features of CysLT1 receptor. In fact, three potent and selective CysLT1 receptor antagonists were able to completely inhibit LTD4-induced response. In turn, cytosolic Ca2+ ([Ca2+]i) increase (EC50 = 3.4 nM +/- 27% CV) was only partially sensitive to pertussis toxin (PTx) as well as to the prenylation inhibitor fluvastatin and to the specific geranylgeranylation and farnesylation inhibitors BAL 9504 and FPT II. Finally, Clostridium sordellii lethal toxin, inhibitor of the Ras family of GTPases, and FTS, a potent methyltransferase inhibitor, were both able to partially inhibit LTD4-induced [Ca2+] increase, suggesting a role for a Ras family member in [Ca2+]i regulation. In conclusion, in dU937 LTD4 signal transduction involves: (a) at least two pathways, one sensitive and one insensitive to PTx; (b) isoprenylated proteins, such as betagamma subunits and, possibly, a small G protein of the Ras family.

Role for inner ring deiodination preventing transcutaneous passage of thyroxine

Creams containing thyroid hormone are commonly employed for cosmetic purposes. To verify whether T(4) applied to the skin surface can enter the bloodstream either directly or as a metabolite, a cream containing L-T(4) [3,5,3',5'-tetraiodothyronine (T(4))] was self-applied by volunteers for 2 wk. No significant variations in urinary iodide, TSH, and serum (total and free) T(4) and T(3) concentrations were observed at any time relative to pretreatment values, whereas rT(3) concentrations increased significantly 6 and 12 h after cream application. The increased rT(3) concentration led us to investigate the presence of inner ring type III deiodinase (D3) activity in human skin. Using human surgical discard skin, we found that T(4) can be carried across human epidermis in a liposome cream. Substantial inner ring deiodination was suggested by the fact that only 10% of transferred thyroid hormone remained as T(4), and T(3) was not detected. We then measured D3 activity in a surgical skin specimen. The K(m) for T(3) was 1.74 nmol/liter, and the maximum velocity was 23.5 fmol/microg microsomal protein/h. In conclusion, our study indicates that normal human skin serves as a substantial, but incomplete, barrier to T(4) passage. D3 plays an important role in augmenting T(4) blockade by inactivating T(4) to rT(3).