Multiple forms of hypogonadism of central, peripheral or combined origin in males with Prader-Willi syndrome.

BACKGROUND: Hypogonadism in Prader-Willi syndrome (PWS) is generally attributed to hypothalamic dysfunction or to primary gonadal defect, but pathophysiology is still unclear. OBJECTIVES: To investigate the aetiology of hypothalamic-pituitary-gonadal axis dysfunction in PWS males. METHODS: Clinical examination and blood sampling for luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, inhibin B and sexhormone-binding globulin (SHBG) were performed in 34 PWS patients, age 5·1-42·7 years, and in 125 healthy males of same age range. All participants were divided into two groups : < or ≥13·5 years. RESULTS: Pubertal PWS patients showed an arrest of pubertal development. Patients <13·5 years had normal LH, FSH, testosterone and 7/10 had low inhibin B. Among those ≥13·5 years, 8/24 patients had normal LH and testosterone, high FSH and low inhibin B. 5/24 had low FSH, LH, testosterone and inhibin B; one showed normal LH and FSH despite low testosterone and inhibin B; 4/24 had low testosterone and LH but normal FSH despite low inhibin B; 6/24 showed high FSH, low inhibin B and normal LH despite low testosterone. Compared with controls, patients <13·5 years had lower LH, inhibin B, similar FSH, testosterone, SHBG levels and testicular volume; those ≥13·5 years had smaller testicular volume, near-significantly lower LH, testosterone, SHBG, inhibin B and higher FSH. CONCLUSION: PWS patients display heterogeneity of hypogonadism: (i) hypogonadotropic hypogonadism of central origin for LH and/or FSH; (ii) early primary testicular dysfunction (Sertoli cells damage); and (iii) a combined hypogonadism (testicular origin for FSH-inhibin B axis and central origin for LH-T axis).

Epicardial fat: the role of testosterone and lipid metabolism in a cohort of patients with Klinefelter syndrome.

CONTEXT: Klinefelter syndrome (KS), in which subjects have additional copies of X chromosomes, is the most common male sex chromosome abnormality, with a prevalence of 1 in 660 and an incidence of about 1 in 500-700 newborns. Its sign and symptoms include infertility, generally low testosterone levels, and an increased prevalence of obesity and metabolic syndrome. Epicardial fat thickness (EFT) reflects visceral adiposity rather than general obesity. OBJECTIVE: The aim of this study was to analyze echocardiographic EFT in a cohort of patients with KS in comparison with non-obese and obese euploid controls, and to evaluate its correlation with biochemical parameters. DESIGN, SETTING AND PARTICIPANTS: Two hundred and twenty-one KS patients referred to our Rare Endocrine Diseases clinic and 77 age-matched controls underwent Doppler echocardiography and a full investigation of anthropometric and body composition, Serum levels of total testosterone (T), estradiol (E2), sex hormone binding globulin (SHBG), fasting plasma glucose, insulin, cholesterol and triglycerides were obtained. All participants underwent dual energy X-ray absorptiometry (DEXA) scan to assess truncal body fat (TrBF). MAIN OUTCOME MEASURE: EFT, body composition and metabolic parameters in KS patients and how they are affected by genotype. RESULTS: EFT was greater in KS patients than in healthy non-obese (NOb) controls, but lower than in obese (OB) controls. When KS patients were divided into groups (hypogonadal; eugonadal; receiving testosterone replacement therapy [TRT]), EFT was greater in hypogonadal patients than in NOb controls and eugonadal patients, but showed no difference from the OB controls or TRT patients. Hypogonadal patients showed increased TrBF in comparison with NOb controls and eugonadal and TRT patients, and similar TrBF to OB controls. As expected, there was a strong correlation between BMI and EFT in both KS patients and controls (P < 0.0001). In contrast, there was a strong inverse correlation between testosterone and EFT in the control group, but not in KS patients. EFT was significantly correlated with TrBF in both populations (P < 0.0001). Multivariate analyses showed that the major determinants of both EFT and TrBF were BMI and the presence of KS itself. Testosterone and triglycerides were not included as variables in the models. CONCLUSION: EFT in hypogonadal KS subjects was similar to that of the obese eugonadal controls. Even though there was a direct correlation between BMI and EFT in both populations, the influence of TrBF on EFT was stronger. The presence of the supernumerary X chromosome appeared to be one of the strongest determinants of EFT and TrBF, independent of testosterone levels.

Mixed complexes of Pt(II) and Pd(II) with ethylsarcosinedithiocarbamate and 2-/3-picoline as antitumor agents.

The [M(ESDT)Cl](n) (M=Pt(II), Pd(II); ESDT=EtO(O)CCH(2)N(CH(3))CS(2)(-), ethylsarcosinedithiocarbamate ion) species have been reacted with 2- or 3-picoline in dichloromethane in order to obtain mixed ligand complexes of the type [M(ESDT)(L)Cl] (L=2-picoline, 3-picoline). The synthesized compounds have been isolated, purified and characterized by means of elemental analyses, (1)H-/(13)C-/(1)H(13)C-HMBC (heteronuclear multiple bonding coherence) NMR and FT-IR spectroscopy. The biological activity of the compounds reported here has been then determined in terms of cell growth inhibition, DNA synthesis inhibition, detection of interstrand cross-links and DNA-protein cross-links, and micronuclei (MN) detection on a panel of tumor cell lines both sensitive and resistant to cisplatin. On the basis of the experimental results, coordination in the above mentioned complexes takes place in a near square-planar geometry, the dithiocarbamate moiety acting as a chelating agent, whereas the two remaining coordination sites are occupied by a chlorine atom and an amino ligand. Above all, [Pt(ESDT)(2-picoline)Cl] complex has shown very encouraging cytotoxicity levels higher or, at least, comparable to those exerted by cisplatin in the same experimental conditions.

Novel triazolium based 11(th) group NHCs: synthesis, characterization and cellular response mechanisms.

The novel NHC ligand precursor 1,4-bis(4-nitrobenzyl)-1H-1,2,4-triazol-4-ium bromide, [HTz((pNO2Bz)2)]Br, has been synthesized and used in the synthesis of the corresponding metal complexes M[Tz((pNO2Bz)2)]Br (M = Cu(I), Ag(I) or Au(I)). These compounds were characterized by several spectroscopic techniques including NMR and mass spectroscopy. The complete series of Au(I), Ag(I) and Cu(I) 1,2,4-triazole based NHC complexes has been synthesized aiming at a SAR study and at identifying the primary cellular targets accounting for their cytotoxic action. The cytotoxic properties of the NHC complexes have been assessed in various human cancer cell lines, including cisplatin sensitive and resistant cells, the most efficacious antiproliferative compound being Cu(I)-NHC, which was able to promote a growth inhibitory effect up to ten times higher than that promoted by cisplatin. A detailed analysis of molecular and cellular pharmacology allowed us to elucidate the role of the metallic core in determining the biological properties. In particular, gold(I) and silver(I) NHC complexes were found to be able to hamper mammalian thioredoxin reductase (TrxR) activity in human A431 cervical cancer cells, ultimately leading to a dramatic alteration of the cellular redox state and to the induction of cell death via apoptosis. Conversely, the copper NHC complex was found to be capable of inhibiting proteasome functionality thus determining the induction of a non-apoptotic cell death pathway.

Homoleptic phosphino copper(I) complexes with in vitro and in vivo dual cytotoxic and anti-angiogenic activity.

Homoleptic, tetrahedral Cu(i) complexes of the type [Cu(P)4]BF4 (1-3), where P are the phosphine ligands, 1,3,5-triaza-7-phosphaadamantane (PTA), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA) and 2-thia-1,3,5-triaza-phosphoaadamantane-2,2-dioxide (PTA-SO2), have been prepared. Novel complexes [Cu(DAPTA)4]BF42 and [Cu(PTA-SO2)4]BF43 have been fully characterized by means of spectroscopic methods, corroborated by XAS-EXAFS analysis of 2. In vitro cell culture experiments revealed a significant antiproliferative activity for Cu(i) compounds against several human cancer cell lines derived from solid tumors with preferential cell growth inhibition towards tumour compared to non-malignant cells. In vitro monitoring of migration and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs) showed an anti-angiogenic effect of copper(i) complexes at sub-cytotoxic concentrations. In vivo studies on the antitumor efficacy and ability to inhibit angiogenesis confirmed the dual cytotoxic and anti-angiogenic properties of Cu(i) derivatives.

Synthesis and biological activity of (hydroxymethyl)- and (diethylaminomethyl)benzopsoralens.

Some benzopsoralens, carrying a hydroxymethyl or a diethylaminomethyl group at the 3, 5, 8, and 11 positions, were prepared, and their biological activity was compared with that of 4-(hydroxymethyl)benzopsoralen (BP). 5-(Hydroxymethyl)benzopsoralen (7b), 11-(hydroxymethyl)benzopsoralen (7c), and 11-(diethylaminomethyl)benzopsoralen (8c) induced marked antiproliferative effects in mammalian cells by simple incubation in the dark; this activity appeared to be related to their ability to inhibit topoisomerase II. Benzopsoralens appeared to be more active, especially BP and 7c, upon UVA activation. Compounds carrying a methyl group at the 4 position together with a hydroxymethyl or diethylaminomethyl at the 8 position (7d and 8d, respectively) were also effective, although to a lower extent; instead, a substituent at the 3 position canceled all activity. Benzopsoralens did not induce interstrand cross-links in DNA in vitro, as seen in the induction of cytoplasmic <> mutations and double-strand breaks in yeast. This behavior is also compatible with their low mutagenic activity in E. coli WP2 and with the absence of any phototoxicity on the skin. For these features, benzopsoralens seem to be interesting potential drugs for PUVA photochemotherapy and photopheresis. The activity shown in the dark is not sufficient for their possible use as antitumor drugs, but it does offer a new model for the study of topoisomerase inhibitors.

DNA damage and cytotoxicity induced in mammalian cells by a tetramethylfuroquinolinone derivative.

1,4,6,8-Tetramethyl-2H-furo[2,3-h]quinolin-2-one [FQ] is an angelicin isoster characterized by a strong photosensitizing activity FQ shows a significant antiproliferative activity also in the dark, i.e., without UVA activation. The cytotoxic activity of FQ in the dark was detected in HeLa cells and in normal human lymphocytes; FQ showed notable antiproliferative effects, barely lower in comparison with ellipticine, used as a reference Similar results were obtained studying the FQ's capacity for forming chromosome aberrations. For both FQ and ellipticine, the chromosomal damage correlated closely with cell killing, when compared with ellipticine at the same levels of survival, FQ appeared to be much less genotoxic. Using alkaline elution we have investigated the ability of FQ to damage DNA. The formation of equivalent amounts of single-strand breaks (SSB) and DNA-protein cross-links (DPC) was observed; in addition, these lesions appeared to be located at the same sites in DNA. Experiments carried out with neutral elution demonstrated the formation of double-strand breaks (DSB). All these data are consistent with an inhibition of topoisomerase II; this hypothesis was confirmed performing an enzymatic test in vitro using topoisomerase II from Drosophila melanogaster embryos.

DNA damage induced by 4,6,8,9-tetramethyl-2H-furo[2,3-h]quinolin-2-one, a new furocoumarin analog: photochemical mechanisms.

Some photochemical and photobiological properties of 4,6,8,9-tetramethyl-2H-furo[2,3-h]quinolin-2-one (HFQ) were studied in comparison with its isomer 1,4,6,8-tetramethyl-2H-furo[2,3-h]quinolin-2-one (FQ) and 8-methoxypsoralen (8-MOP). The HFQ photobinds to DNA forming furan-side monoadducts (MAHFQ) that have molecular structure very similar to those of FQ (MAFQ). Unlike MA8-MOP and MAFQ, MAHFQ no longer photoreact. The HFQ, like FQ, produces moderate amounts of singlet oxygen but no superoxide anions. The HFQ and FQ induce numbers of DNA-protein cross-links (DPC), much more plentiful than those of 8-MOP (about two and seven times, respectively) but no interstrand cross-links. The mechanism of DPC formation was studied in vivo in mammalian cells by alkaline elution and in vitro using a new test mixing histones and DNA from calf thymus. The latter is a very useful technique for the double irradiation protocol. The DNA (or histones) are separately exposed to a first UVA dose in the presence of the sensitizer; then, after its unbound molecules have been removed, histones (or DNA) are added to assemble the chromatin-like complex that is irradiated again. According to in vitro and in vivo methods, DPC appear to be formed by FQ and 8-MOP by a biphotonic process that starts with monoadduct induction in DNA, followed by their conversion into DPC. In the resulting lesions, the sensitizer molecule forms a covalent bridge between the two macromolecules (DPC at length greater than zero). Instead, HFQ induces DPC by a monophotonic process; thus, HFQ is probably not a physical part of the bridge between DNA and proteins, which may be linked together directly, like DPC at zero length induced by UVC.

DNA damage induced by 4,6,8,9-tetramethyl-2H-furo[2,3-h]quinolin-2-one, a new furocoumarin analog: biological consequences.

4,6,8,9-Tetramethyl-2H-furo[2,3-h]quinolin-2-one (HFQ) and its isomer FQ (1,4,6,8-tetramethyl-2H-furo[2,3-h]quinolin-2-one) showed very strong antiproliferative activity in mammalian cells, about two times greater than 8-methoxypsoralen (8-MOP). Both compounds induced DNA-protein cross-links (DPC) but not interstrand cross-links. The FQ generated DPC in a biphotonic process, yielding a new kind of diadduct, whereas HFQ induced DPC by a monophotonic one, probably without its physical participation in the covalent bridge. These lesions gave different toxic responses. Sensitization of FQ led to extensive DNA fragmentation and to a number of chromosomal aberrations. Conversely, HFQ seemed to be completely inactive and 8-MOP gave intermediate results. A strict relationship between DPC formation and induction of chromosomal aberrations was observed. The HFQ did not induce light skin erythemas, whereas FQ was more phototoxic than 8-MOP, thus suggesting that FQ lesions, DPC in particular, may be implicated in skin phototoxicity. Ehrlich ascites cells, a transplantable mouse tumor, inactivated by furoquinolinone sensitization and injected into healthy mice, protected them from a successive challenge by viable tumor cells. This response appeared to be based on an immune mechanism. Comparable amounts of base substitution revertants were scored when testing furoquinolinones and 8-MOP in bacteria but no DPC were detected. This suggests that classic mutagenesis tests on bacteria are insufficient to give adequate information on furocoumarin genotoxicity. Given its features, HFQ can be regarded as an interesting new agent for psoralen plus UVA photochemotherapy and photopheresis.

Photobiological properties of 1'-thieno-4,6,4'-trimethylangelicin.

Some photobiological properties of 1'-thieno-4,6,4'-trimethylangelicin (TTMA), a new isoster of 4,6,4'-trimethylangelicin (TMA) were studied in comparison with the parent compound. The TTMA absorbs UVA light and photobinds in vitro to DNA more efficiently than TMA; however, in Ehrlich cells in vivo TTMA linked to DNA to a lesser extent than the parent compound. In general, the formation of damage into DNA is in line with this last result: In fact, TTMA and TMA form equivalent amounts of interstrand cross-links (ISC) both in vitro in linearized PM2 DNA and in vivo in HeLa cells. In this system TTMA induces DNA-protein cross-links (DPC) more efficiently than TMA; on the contrary, no significant amounts of single-strand breaks were detected with both compounds. The antiproliferative activity of TTMA is consistent with these results, being only slightly more pronounced than that of TMA. Experiments carried out using double irradiation demonstrated that these drugs are capable of inducing antiproliferative effects by biphotonic reactions, including the formation of both ISC and DPC. Thus, replacement of the oxygen atom by a sulfur increases the UV absorption of the drug and its capacity to photobind to DNA in vitro but does not yield a comparable enhancement of its photosensitizing properties in vivo; this might be due to various reasons, for instance to an increase in the lipophilic character that could modify the behavior in vivo.

Synthesis, characterization and in vitro cytotoxicity of new organotin(IV) derivatives of N-methylglycine.

The synthesis and characterization of new coordination compounds of some diorganotins(IV) with N-methylglycine (sarcosine) are reported; all these derivatives mainly tend to assume a chelate structure. As single crystals were not obtained, a large number of experimental techniques were used to accomplish a definitive characterization and determination of their structure. Results obtained by (1)H/(119)Sn NMR, FT-IR and (119)mSn-Mössbauer spectroscopy and thermogravimetric analysis allow us to deduce the pentacoordination for 1:1 (Sn/sarcosine) derivatives [R(2)SnCl(2)(Sar)](+)Cl(-) (R=Me, n-Bu) in a trigonal-bipyramidal structure, and the hexacoordination for 1:2 complexes [R'(2)Sn(Sar)(2)](2+)2Cl(-) (R'=Me, n-Bu, Ph) in an octahedral structure; however, the probability of partially or totally non-chelate structures for some adducts increases with the steric hindrance of the R/R' groups and the number of the sarcosine molecules bound to the tin atom, so that they give rise to fluxional equilibria in solution. Finally, the synthesized compounds have been tested for in vitro cytotoxic activity against human adenocarcinoma HeLa cells showing, in some cases, strong activity even at low concentration.

Characterization studies and cytotoxicity assays of Pt(II) and Pd(II) dithiocarbamate complexes by means of FT-IR, NMR spectroscopy and mass spectrometry.

The precursors [M(ESDTM)Cl(2)] (M=Pt(II), Pd(II); ESDTM=EtO(2)CCH(2)(CH(3))NCS(2)Me, S-methyl(ethylsarcosinedithiocarbamate)) were synthesized as previously reported [J. Inorg. Biochem. 83 (2001) 31] and used to obtain [M(ESDT)Cl](n) (ESDT=ethylsarcosinedithiocarbamate anion) species. The complexes formed through reaction between [M(ESDT)Cl](n) and the two chiral amino-alcohols synephryne (Syn) and norphenylephrine (Nor) have been synthesized, with the ultimate goal of preparing mixed dithiocarbamate/amino metal complexes of the type [M(ESDT)(Am)Cl] (Am=Syn, Nor). These compounds have been isolated, purified and characterized by means of FT-IR, mono- and bidimensional NMR spectroscopy and mass spectrometry ESI/MS (electronspray mass spectra). The experimental data suggest that in all cases coordination of the dithiocarbamate ligand (ESDT) takes a place through the two sulfur atoms, the -NCSS moiety acting as a symmetrical bidentate chelating group, in a square-planar geometry around the M(II) ion, while the other two coordination positions are occupied by the chlorine atom and the amino-alcohol ligand, respectively. In particular, synephrine and norphenylephrine appear to be bound to the metal atom through the amino nitrogen atom by means of a dative bond. Finally, the biological activity of the new complexes has been studied by MTT (tetrazolio salt reduction) test and by detecting the inhibition of DNA synthesis and of clonal growth in various cancer cell lines. All Pd(II) derivatives showed a noticeable activity very close to that of cisplatin, used as reference drug. Moreover, they showed significantly reduced cross-resistance to cisplatin in a pair of cell lines (2008/C13*) with known acquired cisplatin resistance mechanisms.

Pt(II) and Pd(II) derivatives of ter-butylsarcosinedithiocarbamate. Synthesis, chemical and biological characterization and in vitro nephrotoxicity.

This work reports on the synthesis, characterization and biological activity of new coordination compounds of the type [M(TSDTM)X(2)] (M=Pt(II), Pd(II); X=Cl, Br; TSDTM=ter-butylsarcosine(S-methyl)dithiocarbamate) and [Pd(TSDT)X](n) (TSDT=ter-butylsarcosinedithiocarbamate) in order to study their behavior as potential antitumor agents. All the synthesized compounds were characterized by means of elemental analysis, FT-IR, (1)H and (13)C-NMR spectroscopy and thermogravimetric analysis, suggesting a chelate S,S' structure of the TSDTM/TSDT ligand in a square-planar geometry. Finally, the synthesized complexes have been tested for in vitro cytotoxic activity against human leukemic HL60 and adenocarcinoma HeLa cells; the most active compound [Pt(TSDTM)Br(2)], characterized by IC(50) values very similar to those of the reference compound (cisplatin), was also tested for in vitro nephrotoxicity showing a very low renal cytotoxicity as compared to cisplatin itself.

Platinum(II) and palladium(II) complexes with dithiocarbamates and amines: synthesis, characterization and cell assay.

The [M(ESDT)Cl]n (M = Pd or Pt; ESDT = EtO2CCH2(CH3)NCS2, methylamino-acetic acid ethyl ester-dithiocarboxylate) species have been reacted with various amines (py, pyridine; PrNH2, n-propylamine; c-BuNH2, cyclobutylamine; en, ethylenediamine) in dichloromethane or chloroform with the aim to obtain mixed ligand complexes. The neutral complexes [M(ESDT)(L)Cl] (L = py, PrNH2 or c-BuNH2) and the ionic species ([M(ESDT)(L)2]Cl and [M(ESDT)(En)]Cl) have been isolated, and characterized by IR and proton NMR spectroscopies. The crystal structure of [Pd(ESDT)(PrNH2)Cl] has been determined by X-ray crystallography. The behaviour of the complexes in various solvents was described on the basis of the proton NMR spectra. The complexes and the dithiocarbamato intermediates have been tested for in vitro cytostatic activity against human leukemic HL-60 and HeLa cells.

Cell killing and DNA damage induced in cultured mammalian cells by some tetrahydrobenzopsoralenquinones.

The mechanism of action of two tetrahydrobenzopsoralenquinones: 4-methyl-tetrahydrobenzopsoralenquinone (compound 3) and 4-hydroxymethyltetrahydrobenzopsoralenquinone (compound 4) was studied in mammalian cells. These agents differ structurally from earlier benzo and tetrahydrobenzopsoralen derivatives 4-hydroxymethylbenzopsoralen (compound 1) and 4-hydroxymethyltetrahydrobenzopsoralen (compound 2) by the replacement of the benzopyranone with a quinonepyranone. In this study, we evaluated the antiproliferative activity of such derivatives in normal human lymphocytes and CHO cells cultivated in vitro. Compound 4 showed a noticeable antiproliferative activity. Studying the induction of chromosomal aberrations and of SCEs, we demonstrated that compound 4 has a clastogenic effect on mammalian cells. By means of DNA filter elution and protein precipitation techniques we evaluated the DNA damage produced by the tested compounds. Some experiments performed in presence of a DNA synthesis inhibitor showed that ongoing DNA synthesis is involved in cell killing by derivative 4. All data obtained suggest that compound 4 can interfere with the activity of topoisomerase II. Catalytic studies carried out with purified topoisomerase II and bacteriophage DNA confirmed this hypothesis.

DNA damage and topoisomerase II inhibition induced by a benzopsoralen derivative.

The ability of 4-hydroxymethyl-4',5'-benzopsoralen (HMBP) to damage DNA of Chinese hamster ovary cells (CHO) and to inhibit the activity of topoisomerase II in vitro has been studied. This compound is characterized by a fourth ring condensed at the furan-side in the psoralen molecule. Contrary to other known furocoumarin derivatives, HMBP induces chromosomal aberrations in mammalian cells without UVA activation. The lesions induced in the dark by HMBP in DNA were studied by alkaline and neutral elution in CHO cells; comparable amounts of single-strand breaks and DNA-protein cross-links as well as the formation of double-strand breaks were detected. Moreover, HMBP appeared to inhibit the activity of mammalian topoisomerase II in vitro, in both the catenation and the decatenation assay. In these experiments the drug was effective only when it was pre-incubated with DNA substrate. These results are also consistent with the cytotoxic and mutagenic activity of HMBP in the dark, as tested on V79 Chinese hamster cells (V79/HGPRT system).

Synthesis and antiproliferative activity of some variously substituted acridine and azacridine derivatives.

A group of 9-substituted acridine and azacridine derivatives (m-AMSA analogues) were synthesised following classical procedures as potential antitumour agents with inhibitory effects on DNA topoisomerase II. Some were found to have noticeable cytotoxicity against human HL-60 and HeLa cells grown in culture. Their non-covalent interactions with calf thymus DNA have been studied using fluorescence quenching. We evaluated DNA damage produced by the tested compounds by means of DNA filter elution and protein precipitation techniques. Catalytic studies carried out with purified topoisomerase confirmed these agents as antitopoisomerase inhibitors. Chemotherapy of solid-tumour-bearing mice with tested compounds allowed an aza-analogue (compound IIIb), as potent as m-AMSA but less toxic towards the host, to be recognised.

Synthesis of a new platinum(II) complex: anticancer activity and nephrotoxicity in vitro.

New mixed dithiocarbamate-amino Pt(II) complex ([Pt(ESDT)(Py)Cl]) has been recently synthesised with the aim to produce potential anticancer drug able to conjugate cytostatic activity with lack of nephrotoxicity. This complex contains: (1) an amino ligand; (2) a good leaving group (halide); and (3) an S-containing chelating agent potentially able to protect the metal centre from its interaction with S-containing protein-legating sites that are believed to be at the basis of the nephrotoxicity of Pt(II)-based drugs. This complex has been found to be effective as an antiproliferative agent (more active than cis-platin) towards a normal human adenocarcinoma cell line and the corresponding cis-platin-resistant C13 strain. Toxicity tests on the kidney were performed by means of a renal cortical slice model. The slices, prepared with a Brendel-Vitron slicer, were incubated with different doses (0.125-5.0 x 10(-4) M, final concentration) of [Pt(ESDT)(Py)Cl] or cis-platin dissolved in methyl sulphoxide. The platinum(II) complex showed very low renal cytotoxicity as compared with cis-platin; in particular, lipid peroxidation induced by cis-platin appeared about five-fold higher than that induced by [Pt(ESDT)(Py)Cl]. In conclusion, besides being less toxic for the kidney, the results showed that the new synthesised platinum(II) complex appeared in vitro more effective than cis-platin when tested on sensitive and resistant cis-platin tumour cell lines.

Activity of 3-carbethoxyangelicin photolysis products.

3-Carbethoxyangelicin (3-CA), carrying an electron-withdrawing group at the pyrone side, has been prepared to have a fully monofunctional angelicin derivative. 3-CA does not photoreact with DNA and induces a moderate antiproliferative activity. 3-CA proved to be extremely sensitive to ultraviolet A (UVA) light, undergoing rapid photolysis. Only one photolysis product has been isolated and identified. By means of alkaline elution, we observed that 3-CA and its photolysis products are able to induce a large amount of single-strand breaks in DNA in vivo. The results obtained from studying the capacity to produce singlet oxygen suggest that the photodynamic mechanism of action of 3-CA very likely results from its capacity--as well as that of its photolysis products--to produce singlet oxygen.

RNA-protein cross-links induced by sensitization with a pyrroloquinolinone derivative, a furocoumarin analogue.

The capacity of 2,6-dimethyl-9-methoxy-4H-pyrrolo [3,2,1-ij] quinolin-4-one (PQ), a furocoumarin analogue, of inhibiting protein synthesis in Ehrlich cells upon UVA irradiation was investigated. Using 8-methoxypsoralen (8-MOP) as a reference, we observed that in our short-term test the block of RNA synthesis do not affect protein synthesis, which is driven by pre-synthesised molecules of m-RNA; actually 8-MOP, studied at 100 microM concentration, practically abolished RNA synthesis without affecting significantly protein synthesis. Studying PQ sensitization in HL60 cells by alkaline elution and protein precipitation, the formation of covalent RNA-protein cross-links was observed. 8-MOP, assayed in severe experimental conditions, induced only moderate amounts of such lesion. On the basis of the data obtained in experiments carried out using various scavengers or exposing cells to UVA light in a nitrogen atmosphere, this damage appeared to be due to singlet oxygen formation, which is generated by PQ to a large extent. These results are consistent with the data obtained by H. Singh and J.A. Vadasz (Singlet oxygen: a major reactive species in the furocoumarin photosensitized inactivation of E.coli ribosomes, Photochem. Photobiol., 28 (1978) 539-545) on E.coli ribosomes. The lower activity we observed with 8-MOP might be attributed to a different sensitivity of whole mammalian cells in comparison with isolated ribosomes.