Metabolism of a 20-methyl substituted series of vitamin D analogs by cultured human cells: apparent reduction of 23-hydroxylation of the side chain by the 20-methyl group.

We describe here for the first time the effect of introducing a 20-methyl group on the side-chain metabolism of the vitamin D molecule. Using a series of 20-methyl-derivatives of 1alpha,25-(OH)2D3 incubated with two different cultured human cell lines, HPK1A-ras and HepG2, previously shown to metabolize vitamin D compounds, we obtained a series of metabolic products that were identified by comparison to chemically synthesized standards on HPLC and GC-MS. 24-Hydroxylated-, 24-oxo-hydroxylated-, and 24-oxo-23-hydroxylated products of 20-methyl-1alpha,25-(OH)2D3 were observed, but the efficiency of 23-hydroxylation was low as compared with that of the natural hormone and, in contrast to 1alpha,25-(OH)2D3, no truncated 23-alcohol was formed from the 20-methyl analog. These data, taken together with results from other analogs with changes in the vicinity of the C17-C20 positions, lead us to speculate that such changes must alter the accessibility of the C-23 position to the cytochrome P450 involved. Using the HepG2 cell line, we found evidence that the 24S-hydroxylated product of 20-methyl-1alpha,25-(OH)2D3 predominates, implying that the liver cytochrome involved in metabolism is a different isoform. Studies with a more metabolically resistant analog of the series, 20-methyl-Delta(23)-1alpha,25-(OH)2D3, gave the expected block in 23- and 24-hydroxylation, and evidence of an alternative pathway, namely 26-hydroxylation. 20-Methyl-Delta(23)-1alpha,25-(OH)2D3 was also more potent in biological assays, and the metabolic studies reported here help us to suggest explanations for this increased potency. We conclude that the 20-methyl series of vitamin D analogs offers new perspectives into vitamin D analog action, as well as insights into the substrate preferences of the cytochrome(s) P450 involved in vitamin D catabolism.

New synthetic vitamin D analogs with antiproliferative activities.

The introduction of oxygen atoms into different positions of the vitamin D side chain is described. By combining the arising 23-oxa and 25-oxa elements with other structural modifications (19-nor, iso-19-nor, 20-methyl, 20-ene, 20,21-cyclo) calcitriol analogs with remarkable levels of dissociation between beneficial acitivities on cell growth regulation and undesired hypercalcemia were identified. Structure-activity relations are elaborated in a very systematic outline of the Schering drug finding program in this particular class of vitamin D compounds.

Synthesis and biological activity of a novel, highly potent progesterone receptor antagonist.

Herein we describe the chemical synthesis and pharmacological characterization of a novel, highly potent progesterone receptor (PR) antagonist, ZK 230211. The introduction of a 17alpha-pentafluorethyl side chain in the D-ring of the steroid skeleton allowed the combination of high antiprogestagenic activity with little or no other endocrinological effects. In contrast to many other antiprogestins, ZK 230211 did not convert to an agonist in the presence of protein kinase A (PKA) activators and showed high antiprogestagenic activity on both PR isoforms PR-A and PR-B. This high antiprogestagenic activity could also be demonstrated in several in vivo models. Furthermore, this compound displayed only marginal antiglucocorticoid effects. In tumor models ZK 230211 exhibited strong antiproliferative action. The pharmacological properties of ZK 230211 may prove useful in the treatment of endometriosis, leiomyomas, breast cancer, and in hormone replacement therapy.

Synthesis and biological activity of 11,19-bridged progestins.

A synthetic approach to 11,19-bridged progestins is described. The key step in the synthesis is a 6-endo-trig radical cyclisation. The new progestins were tested for their biological activities in vitro and in vivo and compared to those of known progestins.

Synthesis and biological activity of 17-chloro-16(17) unsaturated D-homo antiprogestins.

An efficient approach to 17-chloro-16(17) unsaturated D-homo antiprogestins is described. The key steps of the synthesis are a ring-expansion via dichlorocarbene addition to a 17-silyl enol ether and a palladium catalyzed coupling of an 11 beta-(4-aryltriflate) with tributyl(1-ethoxyethenyl)stannane or diethyl(3-pyridinyl)-borane. The new progesterone antagonists were tested for their biological activities and compared to those of known antiprogestins.

Synthesis and biological testing of 4'-(dimethylamino)-17 beta-hydroxy-17 alpha-(1-propynyl)benzo[12,12a]-11 alpha,18-cyclo-12a,12b-dihomo-13 alpha-estr-4-en-3-one: an interesting RU 38 486 analog.

A partial synthesis of the title compound, 4'-(dimethylamino)-17 beta-hydroxy-17 alpha-(1-propynyl)benzo[12,12a]-11 alpha,18-cyclo-12a,12b- dihomo-13 alpha-estr-4-en-3-one 1, is reported. The key step in this synthesis represents an intramolecular alkenylaryl radical cyclization. Treatment of 18-[bromo-5-(dimethylamino)phenyl]gona-5,9(11)-diene-3,17-dione-3, 17- bis[cyclic 1,2-ethanediyl acetal] 5 with tributyl tin hydride and a radical initiator introduces the desired 11 beta,18-bridge. The reduced progesterone receptor affinity of this RU 38 486 analog contributes valuable information to the empirical characterization of the steroid binding site of the receptor protein and explains the observed lack of in vivo antigestational activity.

Synthesis and biological activities of 8(14)a-homocalcitriol.

8(14)a-Homocalcitriol was synthesized and tested for its biologic activities. It exhibited a vitamin D agonist activity profile. The compound was bound to the pig intestinal receptor with an affinity slightly less than calcitriol, showed the same potency in inducing HL 60 cell differentiation and inhibition of keratinocyte proliferation as calcitriol, and was found to be approximately 10-fold less potent in inducing hypercalcemia and hypercalciuria after a single injection in normal rats.

Progesterone antagonists: tumor-inhibiting potential and mechanism of action.

A new approach for the treatment of breast cancer could be the use of progesterone antagonists. These compounds were originally developed for the inhibition of progesterone-dependent processes and have been shown to be effective in inhibition of nidation and interruption of pregnancy. Although the roles of progesterone and the progesterone receptor in control of cell growth remain unclear, it was found in progesterone receptor positive mammary carcinoma cell lines that the antiprogestin, Mifepristone, had an inhibitory effect on cell growth and a growth-inhibiting action on the DMBA-induced mammary carcinoma of the rat. We have shown that the progesterone antagonists, Onapristone and ZK 112993, which possess a reduced antiglucocorticoid activity compared to Mifepristone, exert a strong tumor-inhibiting effect in a panel of hormone-dependent mammary tumor models. The effects of these compounds were in some systems superior to those of tamoxifen or high dose progestins and comparable to ovariectomy. Although prerequisites for their antiproliferative potency are an affinity to the progesterone receptor as well as a sufficient number of available receptors in the tumors, the strong tumor inhibiting potential of the antiprogestins cannot be explained by a classical anti-hormonal mechanism. Surprisingly, the antitumor activity is evident in spite of elevated serum levels of ovarian and pituitary hormones. It was established by morphometric procedures that treatment with Onapristone triggers differentiation of the mitotically active polygonal tumor epithelial cell towards secretory active glandular structures and acini. All our quantitative light and electron microscopic data indicate that the antitumor action of antiprogestins is accompanied by the initiation of terminal differentiation leading to (apoptotic) cell death. Finally, our flow cytometry studies revealed an accumulation of the tumor cells in the G0G1 phase of the cell cycle, which may result from induction of differentiation since a differentiation-specific G1 arrest has already been proposed for other stem cell systems. It can be concluded from these data that the progesterone receptor antagonists differ in their mode of action from compounds used in established endocrine treatment strategies for mammary carcinoma. The ability of progesterone antagonists like Onapristone to reduce the number of cells in S-phase may offer a significant clinical advantage, since it is established that the S-phase fraction is a highly significant predictor of disease-free survival among axillary node-negative patients with diploid mammary tumors.

Tumor-inhibiting potential of ZK 112.993, a new progesterone antagonist, in hormone-sensitive, experimental rodent and human mammary tumors.

The progesterone antagonists Onapristone (ZK 98.299) and Mifepristone (RU 486) proved to be strong inhibitors of various rodent mammary tumors. Therefore, a further potent antiprogestin, ZK 112.993, and 11 beta-(4-acetyl-phenyl)-analog of Mifepristone, with a high progesterone receptor affinity was tested in experimental rodent and human breast cancer models. In the hormone-dependent MXT(+) mammary tumor of the mouse, treatment of tumors immediately after implantation with 5 mg/kg for 6 weeks led to an inhibition of growth by 95%, being significantly superior to that caused by tamoxifen, diethylstilbestrol and Onapristone. Treatment of established MXT(+) tumors by ZK 112.993 at doses of 0.5, 1.0 and 2.0 mg/kg led to a strong inhibition that equalled that of ovariectomy and surpassed that of Onapristone in the lower doses. In the human, receptor positive mammary carcinoma T61 implanted in male, castrated nude mice, ZK 112.993 (10 mg/kg) significantly retarded tumor growth. Its effect was again superior to Onapristone though weaker than that of tamoxifen. The NMU-induced mammary carcinoma of the rat (established tumors) was inhibited by ZK 112.993 (5 and 10 mg/kg) in a dose-dependent manner slightly superior to Onapristone but weaker than after ovariectomy. Due to its strong antitumor activity and because of the innovative mechanism of action of antiprogesterones in tumor treatment, ZK 112.993 could be of great value for the treatment of breast cancer.

Synthesis of antiprogestational steroids.

The discovery of the first competitive progesterone antagonist RU 38,486 has initiated an intense search for more potent and more selective anti-progestins. Among several hundreds of compounds under preliminary investigation, biological characterization is most advanced for derivatives RU 38,486, ZK 98,734 and ZK 98,299. These compounds do not only differ in relative potency, but are clearly distinguished by their different behaviour in various animal models. Emphasis is laid on the synthetic problems associated with chemical operations in a sterically crowded environment as represented by structures RU 38,486 and ZK 98,299.

Studies on the mechanisms of action of progesterone antagonists.

Antigestagens of RU-38.486-type were investigated in different pregnancy models reflecting either "endometrial" or "myometrial" effects. All antigestagens were found effective inhibitors of nidation in guinea pigs. This was evidence for a role of embryonic progesterone in the earliest events of nidation. No comparable inhibition could be obtained by ovariectomy. A more complex pharmacology was found around day 43 p.c. when the abortion was brought about by expulsion. RU-38.486 had marginal activity only. Antigestagens with reduced anti-glucocorticoid activity tended to induce abortions more effectively and faster. Some antigestagen-prostaglandin combinations were found of extreme abortifacient activity. Surprisingly it seemed that anti-glucocorticoid properties in addition to (or rather than) antigestagenic activities bring about this synergism with prostaglandin. The employed guinea pig model for pregnancy termination thus characterized two types of antigestagens: ideal ones for monotherapy or combined use with prostaglandin, respectively. Antigestagens induced a highly sensitive myometrium to prostaglandin-stimulation (Sulprostone) and a marked softening and dilatation of the cervix. Antigestagens perfectly prime the genital tract for oxytocic stimuli, they do not overcome the arrested uterine prostaglandin-secretion of the pregnant uterus at the same time.

Synthesis of ent-17-(prop-1-ynyl-17 beta-hydroxy-11 beta-(4-(N,N-dimethylamino)-phenyl)-4,9-estradien-3-one, the antipode of RU-38 486.

The title compound was synthesized and tested for its biological activities. It showed neither antiprogesterone nor antiglucocorticoid properties.

New steroids with antiprogestational and antiglucocorticoid activities.

A number of 11-substituted 19-norsteroids with inverse configuration at C-13 were synthesized. 11 beta-Aryl compounds in this series were found to possess antiprogestational and antiglucocorticoid activities.

[Experiences with the metroplasty]. / Erfahrungen mit der Metroplastik.

Report on 34 metroplasties between 1955 and 1980 at the women's hospital in Halle. 20 patients postoperatively delivered 24 children. One patient is pregnant at present. There were 6 abortions. A spontaneous delivery is possible if there are no additional indications for caesarean section. In 26 cases infertility was the indication to perform the metroplasty. In case of coexisting sterility past experience has shown to insist on an exact diagnostic procedure of sterility.

Interaction of convulsive ligands with benzodiazepine receptors.

The gamma-aminobutyric acid (GABA)-benzodiazepine receptor complex, which is composed of distinct proteins embedded in the neuronal plasma membrane, is important for several effects of benzodiazepines, including protection afforded against convulsions. During structural modification of ethyl beta-carboline-3-carboxylate an agent was discovered which has high affinity for brain benzodiazepine receptors but which is a potent convulsant. Also in contrast to benzodiazepines, this type of benzodiazepine receptor ligand favors benzodiazepine receptors in the non-GABA-stimulated conformation, which may explain the convulsive properties.

[Endocrine aspects of ovarian concer. II. Biochemical and histochemical examinations]. / Endokrine Aspekte des Ovarialkarzinoms II. Biochemische und histochemische Untersuchungen.

In the values of estradiol estimated radioimmunologically in the serum in a group of 12 patients with carcinoma of the ovary there were no significant differences to a control group. The histochemical reaction for the visualiztion of steroid-3beta-ol-dehydrogenase was in 3 of 10 cases only slightly positive.