On the mode of action of a new contragestational agent (DL 111-IT)

Effects of ODC on polyamine metabolism, hormone levels, cell proliferation and apoptosis in goose ovarian granulosa cells

Ornithine decarboxylase (ODC) plays an indispensable role in the process of polyamine biosynthesis. Polyamines are a pivotal part of living cells and have diverse roles in the regulation of cell proliferation and apoptosis, aging and reproduction. However, to date, there have been no reports about ODC regulating follicular development in goose ovaries. Here, we constructed ODC siRNA and overexpression plasmids and transfected them into goose primary granulosa cells (GCs) to elucidate the effects of ODC interference and overexpression on the polyamine metabolism, hormone levels, cell apoptosis and proliferation of granulosa cells. After interfering with ODC in GCs, the mRNA and protein levels of ODC and the content of putrescine were greatly decreased (P < 0.05). When ODC was overexpressed, ODC mRNA and protein levels and putrescine content were greatly increased (P < 0.05). The polyamine-metabolizing enzyme genes ornithine decarboxylase antizyme 1 (OAZ1) and spermidine / spermine-N1-acetyltransferase (SSAT) were significantly increased, and spermidine synthase (SPDS) was significantly decreased when ODC was downregulated (P < 0.05). OAZ1, SPDS and SSAT were significantly increased when ODC was upregulated (P < 0.05). In addition, after interference with ODC, progesterone (P4) levels in the culture medium of GCs increased greatly (P < 0.05), while the overexpression of ODC caused the P4 level to decrease significantly (P < 0.05). After ODC downregulation, granulosa cell activity was significantly reduced, the apoptosis rate was significantly increased, and the BCL-2 / BAX ratio was downregulated (P < 0.05). Under ODC overexpression, the activity of GCs was notably increased, the apoptosis rate was significantly reduced, and the BCL-2 / BAX protein ratio was upregulated (P < 0.05). Our study successfully induced ODC interference and overexpression in goose ovarian GCs, and ODC regulated mainly putrescine content in GCs with a slight influence on spermidine and spermine. Moreover, ODC participated in the adjustment of P4 levels in the culture medium of GCs, promoted granulosa cell proliferation and inhibited granulosa cell apoptosis.

Intramolecular oxidative cyclization of N-(2,2,2-trifluoro-1-(phenylimino)ethyl)benzimidamide

A fast and convenient method for synthesis of 1,3-diaryl-5-(trifluoromethyl)-1H-1,2,4-triazole compounds has been described via intramolecular oxidative cyclization of the N-(2,2,2-trifluoro-1-(arylimino)ethyl)benzimidamide intermediates by I₂/KI in excellent yields without any purification. N-(2,2,2-Trifluoro-1-(arylimino)ethyl)benzimidamide intermediates which are used in this project have been synthesized from the reaction of N-aryl-2,2,2-trifluoroacetimidoyl chlorides and benzamide hydrochloride derivatives at room temperature for the first time.

Contragestazol (DL111-IT) inhibits proliferation of human an-drogen-independent prostate cancer cell line PC3 in vitro and in vivo

AIM

To evaluate the antiproliferative activity of contragestazol (DL111-IT) on the human prostate cancer cell line PC3 in vitro and in vivo and to elucidate its potential molecular mechanisms.

METHODS

The cell killing ability of DL111-IT was measured by the 3-(4,5-dimethylthia-zol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent assay method and the tumor xenograft model. The cell cycle was analyzed by flow cytometry and protein expression, including retinoblastoma (pRb), cyclin-dependent kinase 4 (CDK4) and cyclin D1, was detected by Western blotting.

RESULTS

DL111-IT exhibited high efficiency on cell growth inhibition of the human androgen-independent prostate cancer cell line PC3. The drug concentration that yielded 50% cell inhibition (IC50 value) was 9.9 mg/mL. In the PC3 tumor xenograft study, DL111-IT (1.25 mg/kg-20.0 mg/kg) given once a day for 10 days significantly inhibited tumor growth, with the inhibition rate ranging from 21% to 50%. Flow cytometric analysis indicated that DL111-IT could cause G1 arrest in the PC3 cell line, but not apoptosis. DL111-IT enhanced pRb expression and down-regulated CDK4 and cyclin D1 expression, suggesting that cell cycle regulation might contribute to the anticancer property of DL111-IT.

CONCLUSION

DL111-IT inhibits the proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo by a cell cycle regulation pathway.

Antiproliferative activity of contragestazol (DL111-IT) in murine and human tumor models in vitro and in vivo

PURPOSES

To evaluate the antiproliferative activity of contragestazol (DL111-IT) in vitro and in vivo and to elucidate potential molecular mechanisms.

METHODS

Cell killing ability of DL111-IT was measured by MTT/Trypan blue exclusion method and murine and human tumor models; cell cycle was analyzed by flow cytometry; pRb, CDK4 and Cyclin D1 expressions were detected by western blotting.

RESULTS

DL111-IT exhibited high efficiency on cell growth inhibition of 12 cancer cell lines, the IC50 values were 4.1-19.7 microg/ml. In Sarcoma-180 (S180) and Hepatoma-22 (H22) tumor bearing mice models, the inhibition rates were 55.9 and 55.6%, respectively, at the doses of DL111-IT 12.5-50.0 mg/kg for 9 days consecutive administration. Human ovarian carcinoma (HO-8910) xenograft study showed that, nine administrations (within 15 days) of DL111-IT (12.5-50.0 mg/kg) significantly inhibited tumor growth with the inhibition rates ranging from 17.0 to 64.3%. DL111-IT induced G1 arrest and overexpression of pRb, CDK4 and Cyclin D1 were observed in HO-8910 cell line, suggesting that cell cycle regulation might contribute to the anticancer property of DL111-IT.

CONCLUSIONS

DL111-IT could inhibit the proliferation of cancer cells both in vitro and in vivo via a cell cycle regulation pathway.

Analysis of polyamines as markers of (patho)physiological conditions

The aliphatic polyamines, putrescine, spermidine and spermine, are normal cell constituents that play important roles in cell proliferation and differentiation. The equilibrium between cellular uptake and release and the balanced activities of biosynthetic and catabolic enzymes of polyamines are essential for normal homeostasis in the proliferation and functions of cells and tissues. However, the intracellular polyamine content increases in hyperplastic or neoplastic growth. Although the involvement of polyamines in physiological and pathological cell proliferation and differentiation has been well established, the role they play is quite different in relation to cell systems and animal models and is dependent on inducer agents and stimuli. Also, the experimental procedures used to deplete polyamines have been shown to influence the cell responses. In this paper, the assay methods currently in use for polyamines are reviewed and compared with respect to sensitivity, reproducibility and applicability to routine analysis. The relevance of polyamine metabolism and the uptake/release process in many physiological and pathological processes is highlighted, and the cellular polyamine pathways are discussed in relation to the possible diagnostic and therapeutic significance of these mediators.

Search for new chemical entities as menses inducing agents

In continuation of an ongoing program on developing nonsteroidal pregnancy interceptives to be used as a menses regulating agent, a new class of compounds belonging to 3-substituted amino-1-aryl-6-hydroxy-hex-2-ene-1-ones series has been investigated for pregnancy interceptive activity in the hamster and rat. The compounds were administered (subcutaneous) on days 4-8 (hamster) and 5-9 (rat) post coitum (PC). The animals were laparotomized on days 12 (hamster) and 16 (rat) PC. To derive percent efficacy, the total number of implantation was divided by the number of normal and resorbed implantations. Among the 14 compounds evaluated, three were found to intercept pregnancy by 100%. Another compound was active by 75%, whereas the rest were inactive. None of the active compounds were, however, active in rat with this schedule. Results indicate that the observed species- and schedule-specific activity owes its origins to differences in the implantation physiology and early post-implantation development between the two species. The study, nevertheless, offers an insight to the new class of compounds for this activity.

Effects of DL111-IT or combined with RU486 on uterine polyamines biosynthesis in rats during early gestation

DL111-IT, a non-hormonal contragestional agent, revealed synergistic effects in combination with mifepristone (RU486) in some species. The present study was undertaken to clarify the role of DL111-IT when used alone or plus RU486 on uterine polyamines biosynthesis, histologic alteration of decidual cells, and antifertility activity in rats. The levels of polyamines in pregnant rat uterus were determined by formed benzoyl chloride derivatives of polyamines for RP-HPLC. The results showed that all the treated groups including DL111-IT 2.8 mg. kg(-1). d(-1), RU486 3.0 mg. kg(-1). d(-1), and DL111-IT 0.56 mg. kg(-1). d(-1) plus RU486 0.6 mg. kg(-1). d(-1) caused 100% early pregnancy arrest. Uterine putrescine, spermidine, and spermine levels in comparison with vehicle control were declined significantly from d7 of gestation (1 day after treatment) to d9 or d14 (3 days or 8 days after treatment) by Duncan's multiple range test, and accompanied by histologic alterations, edema, degeneration and dissolution of decidual cells with nuclei indefinite in appearance on d8 of gestation (2 days after treatment). The combined administration at lower doses caused the most injury. The data verified that the decrease in uterine polyamine levels and subsequent decidual cells injuries were the critical role of early pregnancy arrest induced by DL111-IT or RU486. The two compounds used in combination with lower dosages revealed greatly synergistic effects.

Termination of early pregnancy in the mouse, rat and hamster with DL111-IT and RU486

The effectiveness of DL111-IT and RU486 given alone and in combination for terminating early pregnancy was tested in the rat, mouse, and hamster. In the mouse and rat, the combination of RU486 and DL111-IT is much more effective in terminating pregnancy than either of the two compounds used alone (single or multiple treatment). A low-effective dose of DL111-IT in combination with a non-effective or a sub-effective dose of RU486, exerted additive or synergistic effects resulting in resorption of embryos and termination of pregnancy. The serum progesterone concentrations were significantly suppressed by these combinations when pregnancy was terminated. In the hamster, single treatment with DL111-IT plus RU486 exhibited a strong effect on interrupting early pregnancy. The ED50 of RU486 in combination of a non-effective dose of DL111-IT was decreased to 163-fold lower dose than RU486 given alone. It is concluded that in mouse, rat, and hamster, the synergistic action between DL111-IT and RU486 not only greatly enhances efficacy in terminating pregnancy but also reduces substantially the dose required to produce this effect.

Luteolytic effects of DL111-IT in pregnant rats

The present studies were conducted to evaluate the effects of DL111-IT [3-(2-ethyl phenyl)-5-(3-methoxy phenyl)-1H-1,2,4 triazol] on ovaries of pregnant rats. Pregnant rats were i.m. treated with DL111-IT 2.5 mg kg(-1) day(-1) or camellia oleum (vehicle control) 0.2 ml/day from day 6 of pregnancy for 1, 3 or 5 days. Blood and ovaries were collected 24 h after the last injection. Ovarian fresh weight and protein contents, activities of the 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) in ovaries, and cell apoptosis of corpus luteum (including hematoxylin-eosine stain, in situ 3'-end labeling and nucleosomal banding) were estimated. Compared with that in the control group, ovarian fresh weight declined 11% and 22% after DL111-IT-3 days and -5 days; protein content dropped 29% after 5-day administration. DL111-IT for 3 days provoked a marked decrease of serum progesterone, by 31% of the control; the activity of 3beta-HSD decreased 34.4% after i.m. DL111-IT for 5 days, while that of 20alpha-HSD increased dramatically after only one injection of DL111-IT (P < 0.01). Histological analysis and in situ 3'-end DNA labeling indicated that DL111-IT induced the pyknosis of cells and the formations of apoptotic bodies and intense oligonucleosomes in luteal cells of pregnant rats. The cell apoptosis induced by DL111-IT was further confirmed by evaluation of nucleosomal DNA fragmentation by agarose gel electrophoresis in cultured luteal cells exposed to DL111-IT for 24 h. In conclusion, all results, including shrunken luteal cells, decreased concentration of protein content and serum progesterone, changed activities of 3beta-HSD and 20alpha-HSD and formation of DNA fragments in luteal cells, showed the luteolytic effect of DL111-IT in pregnant rats.

Pregnane derivatives as pregnancy interceptive agents: efficacy determination on growing trophoblasts (in vitro) and in pregnant hamsters (in vivo)

An in vitro test system was standardized to study potentiality of five hormonally inert pregnane derivatives on growing trophoblasts isolated from ectoplacental cone (EPC) of day 8 hamster embryo. Cells were incubated with different concentrations of respective compounds in surface droplets. The response was determined by analyzing the sequence of changes in cell morphology like attachment, growth, proliferation, differentiation and/or degeneration within 24 or 48 h following seeding. The in vivo efficacy of these compounds was determined in hamster during peri- and immediate post-implantation periods (days 3-8 post coitum). Two compounds 88/583 and 88/585 were found to inhibit not only growth and proliferation of the cells but caused total degeneration within 24 h. The same compounds induced partial to complete resorption of the foetuses in treated animals. Whereas, the other three compounds 88/506, 88/594 and 89/43 that showed lack of comparable potentiality in vitro were found to be equally ineffective in vivo. The results indicate a positive correlationship between in vitro and in vivo activity.

Chemically induced alterations in maternal homeostasis and histology of conceptus: their etiologic significance in rat fetal anomalies

Possible relationships between maternal acid-base-electrolyte imbalance, histological changes in the maternal/extraembryonic tissues (decidua, placenta, membranes enclosing cavities), and fetal anomalies induced by maternotoxic doses of ethylene glycol, sodium salicylate, and cadmium chloride in rats were investigated. Acid-base-electrolyte, histologic and, teratologic studies were conducted concurrently with, as far as feasible, a similar protocol. Ethylene glycol caused 1) maternal homeostatic changes including metabolic acidosis and hyperosmolality, 2) extraembryonic lesions with degeneration of allantois and reduced villigenesis being more prevalent, and 3) materno-fetal effects such as decreases in fetal and maternal body weights, decreased maternal food intake, and fetal abnormalities (vertebral, rib, and sternebral defects). Few of these changes occurred when NaHCO3, an endogenous agent known to correct metabolic acidosis, was coadministered with ethylene glycol. Ethylene glycol-induced maternal metabolic acidosis, concurrent with hyperosmolality, was suspected to contribute toward reduction in villigenesis and fetal anomalies, including body weight reductions. Sodium salicylate induced the following: 1) mild maternal acidosis, hypokalemia, and hypophosphatemia with no significant change in pH; 2) maternal hemorrhage in extraembryonic cavities, papillary proliferation of the visceral yolk sac endoderm, and failure to form the chorioallantoic labyrinth; and 3) resorptions, hydrocephaly, rib defects, and fetal body weight reduction. Upon simultaneous treatment with sodium salicylate, NaHCO3 significantly reduced, and NH4Cl enhanced the incidence of the above histologic and teratologic effects, without significantly altering acid-base values. An etiologic association between the above salicylate-induced maternal and extraembryonic lesions and teratogenicity was likely. Cadmium chloride, whether administered by the intraperitoneal (ip) or intravenous (iv) route, caused 1) hydrocephaly, anophthalmia, vertebral and rib defects, reduction in fetal body weight, resorptions and maternal toxicity (acute peritonitis by the ip route only), and 2) extensive necrosis and hemorrhage in the decidua basalis, hemorrhage in the ectoplacental cone and around Reichert's membrane, and absence of chorioallantoic labyrinth. An etiologic relationship between these teratologic and histologic effects seemed probable, since both were dose-related. From the above studies, it was hypothesized that maternal factors--metabolic acidosis, hyperosmolality, hemorrhages in the ectoplacental cone, extraembryonic cavities, and around Reichert's membrane, and necrosis of decidua basalis--may have, directly or indirectly, reduced fetal nutrition and materno-embryonic gaseous exchange, which ultimately altered fetal development.

Pregnancy interceptive efficacy and biological profile of 3-amino-6,7-dimethoxy-1H-pyrazolo [3,4-b] quinoline (compound 85/83) in rodents

Administration of compound 85/83 during the peri- and post-implantation period intercepted pregnancy in hamster and guinea pig by parenteral route and in hamster by oral route also. The m.e.d. for hamster and guinea pig was 10 and 20 mg/kg, respectively; lower doses were less effective. Restricting the administration to early post-implantation schedule interrupted pregnancy partially in both species. The compound was, however, ineffective in rat and in the pre-implantation schedule (days 1-4 post-coitum) in hamster. When tested in vitro on growing trophoblasts at 13.8 x 10(-5) M concentration, it prevented growth and caused degeneration of the cells within 24 h; lower concentration (9.2 x 10(-5) M) was less effective. The compound was found to be devoid of estrogenic, antiestrogenic, progestational and antiprogestational properties in conventional bioassays. In hormone competition assays, its relative binding affinity (RBA) to estrogen receptor was negligible (0.002% of estradiol-17 beta), while for uterine cytosol progesterone receptors in rabbit and hamster was 0.06 and 0.08% of progesterone, respectively. The compound 85/83 appears to intercept pregnancy by interfering with development of trophoblast cells.

Embryotoxicity and teratogenicity of DL111-IT, an early pregnancy-terminating agent, in the subsequent gestation following administration in rats

DL 111-IT is a new non-hormonal early pregnancy-terminating agent. The subsequent embryotoxic and teratogenic effects of DL111-IT were studied in the rats whose first pregnancy had been terminated by the agent. The secondary pregnancy of the treated rats were allowed to initiate at 30-, 45-, and 90-day intervals, respectively, after the termination of the first pregnancy. The toxicities primed with DL111-IT, such as resorbed embryos and nephrohydrosis fetuses, were found to be 8.0% and 8.5%, respectively, in the rats with pregnancy at 30-day interval. This is significantly different from 4.0% resorbed embryos and 2.4% nephrohydrosis fetuses in vehicle control (P less than 0.05). However, the rate of resorbed embryos decreased to 7.0% or 6.0% in the rats with pregnancy at 45- or 90-day intervals, respectively. No other significant embryotoxicity and teratogenicity were observed in those rats initiating their pregnancy 45 days later after first-pregnancy termination by DL111-IT. Thus, DL111-IT appears to have very low subsequent toxicity in the course of rat pregnancy cycles.

A chemical classification of nonsteroidal antagonists of sex-steroid hormone action

A highly varied collection of nonsteroids have been reported over the last forty years as being able to exert an antihormonal action versus steroid hormones in vivo. This diversity is partly explained by the manifold molecular targets of these compounds which may be either enzymes or receptors (leading to inhibition of steroid production and action respectively) and by the different possible levels of interference within feedback loops between the central nervous system, pituitary, gonads and other peripheral organs. The present chapter is a chemist's classification of some of these structures often in the absence of detailed biochemical data. Nonsteroid antiestrogens (and estrogens) most often share a common feature with diethylstilbestrol and consequently the effects of structural modifications on biological activities can be studied in a rational manner. This is not the case for non-steroidal antiandrogens that we have only been able to classify into conventional chemical groups. Nor have any true lead compounds nor well-defined chemical classes been identified for nonsteroid antiprogestogens. This is however the only hormonal class where natural products play an important role.

Contraceptive and hormonal properties of a new 1,4-dihydro-2-oxoquinoline derivative (compound 84-182) in rodents and rhesus monkeys

Compound 84-182 prevented pregnancy when administered subcutaneously at 10 mg/kg dose on days 3-8 post-coitum in hamsters and on days 6-10 post-coitum in guinea pigs. At lower doses, while in hamsters there was a marked reduction in implantation number, majority of implantations in guinea pigs showed signs of resorption. The compound was ineffective when administered at 10 mg/kg dose on days 1-3 or 6-7 post-coitum in hamsters and on days 1-5 or 4-8 post-coitum in rats. In rhesus monkeys, treatment with the compound at 5 and 10 mg/kg doses on days 16-21 of the menstrual cycle induced frank vaginal bleeding between days 21 and 24. Treatment on days 21-30 or after confirmation of pregnancy on days 32-36 was ineffective. In conventional bioassays, the compound was devoid of any estrogenic, antiestrogenic, progestational, antiprogestational, androgenic or antiandrogenic properties at the contraceptive dose. In competitive protein binding assay, the compound showed relative binding affinity (RBA) of less than 0.1% and 0.28% of progesterone, respectively, for rabbit and hamster uterine cytosol progesterone receptors. Its RBA for rat uterine cytosol estrogen receptors was less than 0.1% of estradiol-17 beta.