The effects of desogestrel and ethinylestradiol combination in normal and hyperandrogenic young girls: speculations on contraception in adolescence

Hormone profile and ovarian morphology were studied in two groups of adolescents (group 1:19 girls with slight signs of hyperandrogenism; group 2: 14 normal adolescents) in basal conditions and during a contraceptive combination of 30 micrograms ethinyl estradiol (EE) and 150 micrograms desogestrel (D). Treatment was associated with a low incidence of side effects in both groups. In group 1, acne generally improved within 12 months while hirsutism was only reduced in some subjects (58%) after 12 months of therapy (basal hair score 8.50 +/- 1.60 vs 5.81 +/- 1.53 p less than 0.001). Significant falls in plasma levels of LH, total and free testosterone and an increase in sex-hormone-binding globulin levels were observed during treatment especially in group 1. High percentage of multifollicular ovaries (75%) characterized hyperandrogenic subjects. Ovarian volume and number of follicles, higher in group 1 than 2 in basal conditions, showed a significant reduction in both groups and normal ovarian morphology was restored in hyperandrogenic subjects. Considering the high incidence of hyperandrogenemia in adolescence and its implications, our data suggest that the EE.D combination suits adolescent biological condition and is one of the suitable contraceptive methods in adolescents which also has therapeutic effects.

Frameshift lesions induced by oxazolopyridocarbazoles are recognized by the mismatch repair system in Escherichia coli

The simple reversible intercalating agent isopropyl-OPC (iPr-OPC) induces frameshift-1 mutations in Salmonella typhimurium and Escherichia coli. The mutagenic responses of S. typhimurium and E. coli wild-type strains are not proportional to the amount of drug intercalated into double-stranded nucleic acids in living bacteria; it occurs only above a minimum level of binding. The fact that mismatch-repair-deficient (mutS) as well as adenine-methylation-deficient (dam) E. coli mutants are hypermutable at low concentrations of iPr-OPC suggests that the majority of mutants induced by this intercalating drug occur as mismatch-repairable mutations (or lesions) in the newly synthesized DNA strand close to the replication fork.

Pattern of recognition of DNA by mammalian DNA topoisomerase II

The antitumor drug VP-16 stabilizes the topoisomerase II-DNA covalent complexes formed in an intermediate step of the isomerization reaction. The location of the sites of formation of these complexes and their relative strength were studied in vitro using pBR322. Sequences alignment of the regions containing the 24 detectable sites allows to identify GCGCGC-(N) alpha-TGAC with 9 less than or equal to alpha less than or equal to 25 as the DNA sequence recognized by topoisomerase II to form a cleavable complex. Changes in the last two nucleotides of the sequence determine weaker complexes.

Anti-sense oligonucleotides as potential antitumour agents: prospective views and preliminary results

The expression of some proto-oncogenes (c-myc, N-myc, epidermal growth factor receptor) is frequently enhanced in several human malignant tissues. The reduction of level of this expression through the use of anti-sense RNA or anti-sense oligodeoxynucleotides might therefore offer a new way to modify at the somatic level some genetic traits controlled by these oncogenes and possibly related to the maintenance of the transformed phenotype. This approach, although interesting, is paved with considerable conceptual and technical difficulties: multigene involvement in many natural oncogenic processes as well as delivery and stability of the anti-sense nucleic acids. This paper briefly discusses some of these points and presents preliminary results obtained with the alpha-anomeric oligodeoxyribonucleotides.

Introduction of definite amounts of nonpermeant molecules into living cells after electropermeabilization: direct access to the cytosol

The possibility of introducing definite amounts of nonpermeant molecules into electropermeabilized living cells has been approached by quantifying the amounts of Lucifer Yellow (LY; a 457-Da highly fluorescent molecule) and Phytolacca americana (Pokeweed) antiviral protein (PAP; a 30,000-Da ribosome-inactivating protein) retained by the cells after closure of the electric-field-induced transient structures of permeation. Without the electropermeabilization, these two molecules enter the cell only in very small amounts by fluid-phase pinocytosis. Under our experimental conditions, using the NIH 3T3 cells, the intracellular LY concentration can reach a value equivalent to the extracellular concentration and can be regulated by controlling the external concentration. We describe the use of LY in a rapid and efficient test for the determination of the best electrical-shock conditions of other cell lines. After electropermeabilization, PAP is 2 X 10(5) times more cytotoxic. Its toxicity can be detected at external concentrations (10(-11) M) corresponding to less than 10 internalized molecules per electropermeabilized cell. Therefore, after electropermeabilization, the nonpermeant molecules have a direct access to the cytosol and the biological effect of nonpermeant substances can be revealed.

alpha-DNA. VI: Comparative study of alpha- and beta-anomeric oligodeoxyribonucleotides in hybridization to mRNA and in cell free translation inhibition

alpha and beta-anomeric d(G2T12G2) oligodeoxyribonucleotides were compared for their hybridization to rA12: the observed melting temperatures are 27 degrees C for beta-oligodeoxyribonucleotide/RNA hybrid and 53 degrees C for alpha-oligodeoxyribonucleotide/RNA. alpha-oligonucleotides with the four bases, complementary to natural mRNAs, were synthesized for the first time, labeled at their 5'-end with [32P] and used as probes in Northern blot experiments. In spite of these higher affinities for their target RNA's, they were unable to block translation of natural or synthetic mRNA's in rabbit reticulocyte lysate. We have studied the RNase H activity on model rA12:alpha- or beta-d(G2T12G2) hybrids or on mRNA:alpha- or beta-oligonucleotides hybrids. Specific hybridization protects RNA strech when using alpha-oligonucleotides but not beta-oligonucleotides. Thus, our results show the inability of RNase H to degrade RNA in alpha-oligodeoxyribonucleotides:RNA duplexes.

Physicochemical and pharmacological properties of the antitumor ellipticine derivative 2-(diethylamino-2-ethyl)9-hydroxy ellipticinium-chloride, HCl

2-(Diethylamino-2-ethyl)9-hydroxyellipticinium-chloride, HCl (DHE), a new congener of the antitumor agent elliptinium acetate (Celiptium) (NMHE), has recently been selected for phase I clinical trials. NMHE has a methyl group at nitrogen 2 on the ellipticine ring while DHE possesses a basic diethylaminoethyl chain at this position. Compared to NMHE, the presence of the diethylaminoethyl side chain results in the following: a significant increase in the lipophilicity of the drug; no significant modification in either the binding constant values to DNA or the ability to intercalate between DNA base pairs; a marked decrease in the unwinding angle value of supercoiled DNA; and no significant change in the alteration of the catalytic activity of topoisomerase II in vitro. DHE appears to act as a simple reversible intercalating agent as shown by the selective mutagenic effect on Salmonella TA 1977 tester strain and by its inability to induce the SOS functions in a sfiA lac fusion containing Escherichia coli strain. From a pharmacological point of view, the presence of the diethylaminoethyl chain results in a 2-fold increase in the cytotoxicity to L1210 cultured cells, a strong increase in the antitumor efficiency on experimental murine tumors such as L1210 and P388 leukemia, B16 melanoma, M 5076 reticulosarcoma, and colon 38 adenocarcinoma, and finally an objective decrease in the acute and subacute toxicity in mice, rat, and macaque. The absence of significant differences in the interaction of NMHE and DHE with their potential targets in vitro leads to the hypothesis that the superiority of DHE in terms of cytotoxicity and antitumor efficiency may be due to an increase in the diffusion across cellular membrane and a more favorable biodistribution in vivo.

Alpha-DNA. IV: Alpha-anomeric and beta-anomeric tetrathymidylates covalently linked to intercalating oxazolopyridocarbazole. Synthesis, physicochemical properties and poly (rA) binding

A new set of molecules made of an intercalating agent (oxazolopyridocarbazole, OPC) covalently linked through a polymethylene chain of various length to the 3' end of alpha-anomeric or beta-anomeric tetradeoxynucleotides (alpha- or beta-T4) have been synthesized. The beta-thymidylate modified compound (beta-T4C5OPC) is able to interact with the complementary sequence, beta-poly (rA); this interaction is strongly stabilized compared to the parent compound, beta-oligo(dT)4 and is specific for poly (rA). The molecule synthesized from the unnatural alpha-anomer, alpha-T4C5OPC, is also able to interact with poly (rA) leading to the formation of an alpha-beta hybrid stabilized by the energy provided by the OPC moiety. The stoechiometry of the binding reaction shows that an A-T pairing occurs in the alpha-beta heterohybrids. Tm studies reveal that the alpha-beta heterohybrids are more stable than their beta-beta counterparts.

Isolation and characterization of the glutathione-elliptinium conjugate in human urine

In a cancer patient given 100 mg/m2 elliptinium by intravenous infusion, the glutathione conjugate was found in urine. This metabolite was isolated after ion-exchange treatment and high performance liquid chromatography. Its structure was assessed by fast-atom bombardment mass spectrometry and comparison with an authentic sample.

alpha-DNA II. Synthesis of unnatural alpha-anomeric oligodeoxyribonucleotides containing the four usual bases and study of their substrate activities for nucleases

This paper describes for the first time the synthesis of alpha-oligonucleotides containing the four usual bases. Two unnatural hexadeoxyribonucleotides: alpha-[d(CpApTpGpCpG)] and alpha-[d(CpGpCpApTpG)], consisting only of alpha-anomeric nucleotide units, were obtained by an improved phosphotriester method, in solution. Starting material was the four base-protected alpha-deoxyribonucleosides 3a-d. Pyrimidine alpha-deoxynucleosides 3a and 3b were prepared by self-anomerization reactions followed by selective deprotection of sugar hydroxyles, while the two purine alpha-deoxynucleosides 3c and 3d were prepared by glycosylation reactions. In the case of guanine alpha-nucleoside derivative a supplementary base-protecting group: N,N-diphenylcarbamoyl was introduced on O6-position in order to avoid side-reactions during oligonucleotide assembling. The hexadeoxynucleotide alpha-[d(CpApTpGpCpG)] was tested as substrate of selected endo- and exonucleases. In conditions where the natural corresponding beta-hexamer was completely degradated by nuclease S1 and calf spleen phosphodiesterase, the alpha-oligonucleotide remained almost intact.

Quantification by fluorescence of apurinic sites in DNA

Time dependent fluorescence is observed when single or double stranded DNA with apurinic sites are mixed with 9-NH2-ellipticine. A concentration dependent plateau is obtained which is linearly related to the ratio of apurinic sites in DNA. We therefore suggest that it is possible to have a direct measurement of apurinic sites in DNA by fluorescence.

Oxidative biotransformation of the antitumour agent elliptinium acetate: Structural characterization of its human and rat urinary metabolites

The electrophilic properties of the antitumour drug N(2)-methyl-9-hydroxyellipticinium acetate (Celiptium) are revealed by the detection of thiol-conjugate metabolites in man and rat urine. Besides the unchanged drug and its glucuronide, the cysteinyl- (in man) and the N-acetylcysteinyl- (in man and rat) conjugates have been unambiguously characterized using NMR, UV and mass spectral data. The urinary excretion profile exhibits total excreted products of 21% (in man) and 9% (in rat) with respect to the administered dose. The unchanged drug is found to be the major excreted compound from urine in both species (17% in man, 6.3% in rat); whereas the glucuronide (2.6% in man, 1.5% in rat), cysteinyl- (1.3% in man) and N-acetylcysteinyl- (0.2% in man, 1.2% in rat) conjugates represent the minor excreted compounds. The presence of the latter thio-conjugates provides an indirect proof of the in vivo generation of an oxidized intermediate form of the administered drug.

Relationship between cytostatic activity of oxazolopyridocarbazoles and accessibility of DNA intercalation sites in living bacteria

The ability of oxazolopyridocarbazole (OPC) derivatives to interact with DNA in living bacteria through reversible intercalation has been determined by using as probes their selective mutagenic effect on Salmonella typhimurium TA 1977 and TA 1537 as detected by frame-shift-1 reversion, the absence of intervention of the error-prone repair system on the mutagenic efficiency, the absence of induction of the SOS functions, and the absence of effect of recA and uvrB mutations on their bacteriostatic properties. Involvement of simple reversible intercalation as the event responsible for the bacteriostatic effect of the drugs has been further investigated by the establishment of a significant correlation between the maximum number of accessible intercalating sites in living bacteria and the bacteriostatic effect expressed in terms of the ED50. This correlation has been established by using bacteria spontaneously exhibiting different sensitivities toward the drugs as well as a resistant strain obtained by adaptation in the presence of increasing amounts of isopropyl-OPC. The number of intercalating sites in living bacteria was determined by using the change in the fluorescence properties of the drugs upon binding to intercalating sites. The results obtained clearly demonstrate that the number of intercalating sites is the parameter that controls the bacteriostatic effect of the drugs, indicating that DNA is the target for these drugs and that reversible intercalation is responsible for the cytostatic effect.

Uptake, cytofluorescence, and cytotoxicity of oxazolopyridocarbazoles (amino acid-ellipticine conjugates) in murine sarcoma cells

The uptake, cytofluorescence, and cytotoxicity of elliptinium (NMHE) and a series of fluorescent oxazolopyridocarbazoles [amino acid-ellipticine conjugates (AA-NMHE)] were studied in murine sarcoma cells. For all these drugs, the uptake was rapid, directly proportional to the drug concentration, and unaffected by metabolic inhibitors which is consistent with a diffusion mechanism. By 4 h, the intracellular concentration of NMHE exceeded the external drug concentration by about 100 times; this suggests that the toxicity of NMHE is not, as previously assumed, limited by its transport across tumor cell membranes. Conjugation of NMHE with aliphatic amino acids increased the cellular uptake 5- to 7-fold. Cellular exposure to AA-NMHE conjugates resulted in the appearance of granular cytoplasmic fluorescence which was readily translocated to the nucleus upon continued exposure to fluorescent light. The cytotoxicity of the AA-NMHE conjugates (drug concentration required to reduce colony formation by 63% on the exponential part of the survival curve = 3-14 microM) was less than of NMHE (drug concentration required to reduce colony formation by 63% on the exponential part of the survival curve = 0.7 microM) as shown by colony formation following 4 h drug exposure. In contrast, the isoleucine-NMHE conjugate was the most cytotoxic compound (drug concentration required to reduce colony formation by 63% on the exponential part of the survival curve = 0.045 microM) when the drug exposure period was extended to 8 days. The general lower toxicity of the AA-NMHE conjugates is likely due to loss of the phenolic character of the NMHE moiety; therefore, attempts to link NMHE to amino acids remain attractive but will have to be done without affecting the 9-hydroxy group of NMHE.

Frameshift mutagenesis in Salmonella typhimurium by reversible DNA intercalators: effect of a UVR B mutation

The simple reversible intercalating agents isopropyl-oxazolopyridocarbazole and 9-aminoacridine have been found to induce frameshift -1 mutations at a much lower level in Salmonella typhimurium delta uvrB TA 1537 than in the uvr+ wild type TA 1977 strain. This phenomenon can neither be explained by differential cytotoxicity of the drug nor by selective permeation and accessibility to intercalating sites to bacterial DNA. These finding indicate that the lower mutagenicity of intercalating agents in the delta uvrB strains does not result from nonspecific phenotypic modifications of parameters which control the mutagenesis. That leads to the hypothesis that in agreement with the Streisinger's model, the excision repair system could be directly involved in the appearance of frameshift mutations.

Peroxidase-catalyzed covalent binding of the antitumor drug N2-methyl-9-hydroxyellipticinium to DNA in vitro

In the presence of DNA, the antitumor drug N2-methyl-9-hydroxyellipticinium (elliptinium; NMHE) [Le Pecq, J. B., Gosse, C., Dat-Xuong, N., & Paoletti, C. (1975) C. R. Seances Acad. Sci., Ser. D 281, 1365-1367] is oxidized by the horseradish peroxidase-hydrogen peroxide (HRP-H2O2) system to the quinone imine derivative N2-methyl-9-oxoellipticinium (NMOE) [Auclair, C., & Paoletti, C. (1981) J. Med. Chem. 24, 289-295], which interacts with DNA according to the intercalation mode. When excess H2O2 was used, the major part of the quinone imine was further oxidized to the o-quinone N2-methyl-9,10-dioxoellipticinium [Bernadou, J., Meunier, G., Paoletti, C., & Meunier, B. (1983) J. Med. Chem. 26, 574-579]. In the presence of stoichiometric amounts of H2O2 (H2O2/NMHE = 1), NMOE reacts with DNA, yielding a fluorescent compound irreversibly linked to the nucleic acid, which is related to the covalent binding of the ellipticinium chromophore. Under optimal reaction conditions, NMHE binding occurs according to a first-order process (k = 4.3 X 10(-3) min-1) with a linear increase with respect to drug to nucleotide ratio up to a maximum binding of 1 NMHE per 20 base pairs (r = 0.05). The fluorescence spectra (ex, 330 nm; em, 548 nm) of NMHE bound to DNA, the occurrence of energy transfer from the DNA to the drug, and the DNA length increase of the DNA-NMHE adduct suggest that the binding occurs at the intercalating site with limited denaturation of the DNA helix.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficient breakage of DNA apurinic sites by the indoleamine related 9-amino-ellipticine

The aromatic amine, 9-NH2-ellipticine, is a synthetic DNA intercalating derivative of the antitumor agent ellipticine, which breaks circular DNA containing apurinic sites. This breakage is inhibited when the apurinic (AP) sites are reduced. The concentration of 9-NH2-ellipticine required to get a significant effect (0.1 microM) is the lowest known among chemicals which induce the same breakage reaction. Comparison with the action of structurally related amines shows that the amino-indole structure is specific for AP sites. The ability of ellipticine derivatives to induce breakage in DNA containing apurinic sites is related to the nucleophile substituent in position 9. Two ellipticine derivatives with known antitumor activity, BD 40 and 9-OH-ellipticine, were able to break purified DNA at apurinic sites.

A revised structure of the antitumor drug elliptinium--amino(acid) adducts

Using simple organic reactions and spectrometric techniques (nuclear magnetic resonance and mass spectrometry), we propose a revised structure of the adducts obtained through the H2O2-peroxidase oxidation of the antitumor drug ellipticinium and aliphatic amino(acid) compounds. These derivatives display an oxazole ring structure between the O(9)- and N(10)- atoms.

Synthesis and cytotoxic activity of hydroxylated derivatives of olivacine in relation with their biotransformation

The chemical synthesis of 9-hydroxyolivacine and 7-hydroxyolivacine based on a biomimetic approach is described. These two hydroxylated derivatives have been found as main in vitro metabolites of olivacine after incubation with rat hepatic microsomes. The pretreatment of animals with benzo[a]pyrene caused a large increase in both microsomal hydroxylations, whereas the pretreatment with phenobarbital caused a weak increase, with a preservation of 9-hydroxylation/7-hydroxylation ratio greater than 1 in both cases. The two hydroxyolivacines have been also found as principal in vivo metabolites of olivacine in rat bile as glucuronide and sulfate conjugates. The pretreatment of animals with benzo[a]pyrene reverses the 9-hydroxyolivacine/7-hydroxyolivacine ratio excretion in bile to a value that is less than 1. In both in vitro and in vivo experiments, the free metabolites were identified by HPLC and UV-visible, MS, and 1H NMR spectra. Hydroxylation at position 9 increases the in vitro cytotoxicity against leukemia L1210 cells (ID50 = 0.06 microM compared to 2.03 microM for olivacine) and an opposite effect is observed for hydroxylation at position 7 (ID50 = 12.8 microM). On the other hand, hydroxylation at position 9 has no effect on the in vivo antitumor activity against L1210. This might be related to the oxidative and conjugative metabolic pathways that play an important role in antitumor activity and deactivation of olivacine and its hydroxy metabolites.

Selective binding of elliptinium acetate onto the 3'-terminal ribose of diribonucleosides monophosphates

We report the full structure of two elliptinium diribonucleosides monophosphate adducts: the oxidized form of this antitumor agent alkylates very selectively the pX ribose of ApX (X = G or U) leading to a spiro derivative, where the C10 atom of ellipticine skeleton is linked to both sugar oxygen atoms 2' and 3'. No other adducts could be detected, specially the expected ones corresponding to the usual alkylation sites of bases.

Evidence for electrophilic properties of N2-methyl-9-hydroxy ellipticinium acetate (Celiptium) from human biliary metabolites

The human biliary metabolism of the antitumor agent N2-methyl-9-hydroxyellipticinium acetate is described. Three major compounds have been identified by high-performance liquid chromatography and comparison with synthetic reference derivatives: the unchanged drug, the O-glucuronide conjugate and the cysteinyl-ellipticinium adduct. The latter one is the expected detoxification compound of an intermediate electrophilic quinone-imine derivative generated in vivo. This result provides a further evidence that hydroxylated forms of ellipticine derivatives might be activated by a biooxidation route.

Use of a new DNA intercalating fluorescing probe for studies on the mechanism of frameshift mutagenesis in Salmonella typhimurium

As a general rule, ellipticine derivatives are mutagenic and intercalate into double-stranded nucleic acids. We have tested a new fluorescent ellipticine compound, 10[(1-carboxy-2-methylpropylidene)-amino]-9-hydroxy-2-methylell ipticinium (val-NMHE), for establishing the relationship between the amount of drug bound to nucleic acids in situ in Salmonella typhimurium and its biological effects: decrease of growth rate and mutagenesis. Val-NMHE is mutagenic only on Ames'strain TA 1977 which carries a + 1 frameshift mutation. On a per cell basis, the number of revertants is not linearly correlated to the amount of drug bound to nucleic acids: this number is relatively higher for increasing amounts of drug. This effect is not related to the mere probability of interaction between the drug molecule and its target, a GGGG/CCCC sequence. It might be explained by other hypotheses briefly discussed herein.

Covalent binding of the antitumor agent N2-methyl-9-hydroxy-ellipticinium acetate (NSC 264137) on RNA and poly A in vitro

The antineoplastic compound N2-methyl-9-hydroxyellipticinium (9-OH-NME) is able to bind to different biological molecules after an oxidative activation by horseradish peroxidase and hydrogen peroxide. In this study, the efficient covalent binding in vitro of 9-OH-NME onto RNA and poly A is described. The phenomenon is analyzed by different HPLC methods and the yield of binding is determined using [3H]9-OH-NME. For an initial ratio drug per nucleotide of 0.07, the rb obtained (ratio of drug bound per nucleotide) of 0.026 for RNA and 0.044 for poly A, which represent respectively a yield of 40% and 60% for the drug fixation onto these macromolecules. These facts demonstrate the high electrophilicity of para-quinone-imine derivatives in ellipticinium series.