Antiproliferative and Antimetastatic Properties of 16-Azidomethyl Substituted 3-O-Benzyl Estrone Analogs

Four diastereomers of 16-azidomethyl substituted 3-O-benzyl estradiol (1-4) and their two estrone analogs (16AABE and 16BABE) were tested for their antiproliferative properties against human gynecological cancer cell lines. The estrones were selected for additional experiments based on their outstanding cell growth-inhibiting activities. Both compounds increased hypodiploid populations of breast cancer cells, and 16AABE elicited cell cycle disturbance as evidenced by flow cytometry. The two analogs substantially increased the rate of tubulin polymerization in vitro. 16AABE and 16BABE inhibited breast cancer cells' migration and invasive ability, as evidenced by wound healing and Boyden chamber assays. Since both estrone analogs exerted remarkable estrogenic activities, as documented by a luciferase reporter gene assay, they can be considered as promising drug candidates for hormone-independent malignancies.

Oxidized Juncuenin B Analogues with Increased Antiproliferative Activity on Human Adherent Cell Lines: Semisynthesis and Biological Evaluation

Phenanthrenes have become the subject of intensive research during the past decades because of their structural diversity and wide range of pharmacological activities. Earlier studies demonstrated that semisynthetic derivatization of these natural compounds could result in more active agents, and oxidative transformations are particularly promising in this regard. In our work, a natural phenanthrene, juncuenin B, was transformed by hypervalent iodine(III) reagents using a diversity-oriented approach. Eleven racemic semisynthetic compounds were produced, the majority containing an alkyl substituted p-quinol ring. Purification of the compounds was carried out by chromatographic techniques, and their structures were elucidated by 1D and 2D NMR spectroscopic methods. Stereoisomers of the bioactive derivatives were separated by chiral-phase HPLC and the absolute configurations of the active compounds, 2,6-dioxo-1,8a-dimethoxy-1,7-dimethyl-8-vinyl-9,10-dihydrophenanthrenes (1a-d), and 8a-ethoxy-1,7-dimethyl-6-oxo-8-vinyl-9,10-dihydrophenanthrene-2-ols (7a,b) were determined by ECD measurements and TDDFT-ECD calculations. The antiproliferative activities of the compounds were tested on different (MCF-7, T47D, HeLa, SiHa, C33A, A2780) human gynecological cancer cell lines. Compounds 1a-d, 4a, 6a, and 7a possessed higher activity than juncuenin B on several tumor cell lines. The structure-activity relationship studies suggested that the p-quinol (2,5-cyclohexadien-4-hydroxy-1-one) moiety has a considerable effect on the antiproliferative properties, and substantial differences could be identified in the activities of the stereoisomers.

Stereoselective synthesis of new type of estradiol hybrid molecules and their antiproliferative activities

To prepare new type of estrane hybrid molecules, we chose 3-methoxy- and 3-benzyloxy-17β,16β-epoxymethylene-estra-1,3,5(10)-trienes as starting materials (2 and 5). These steroid oxetanes were transformed with ethylene glycol in the presence of BF₃.OEt₂ into 3-methoxy- and 3-benzyloxy-16β-(2'-oxa-4'-hydroxy)butyl-17β-hydroxy-estra-1,3,5(10)-trien-17β-ols (3a and 6a). Iodination of the terminal hydroxy group afforded iodo derivatives 3b and 6b, which underwent one-pot 3-O-alkylation with unprotected ascorbic acid to yield 3c and 6c. The same process with salicylic acid led to 2-O-alkylated salicylic acid derivatives 3d and 6d. Iodo derivatives 3b and 6b underwent nucleophilic exchange reaction with NaN₃ furnishing the corresponding azido compounds 3e and 6e. These compounds were subjected to azide-alkyne CuAAC reactions with phenylacetylene and their p-substituted derivatives to form 1,4-substituted triazoles 3f-h and 6f-h. The reduction of 3e and 6e with hydrazine hydrate in the presence of Raney Ni provided the corresponding amino derivatives 3i and 6i. These compounds were reacted further with varied substituted benzoic acids to deliver terminal benzamido derivatives 3j-m and 6j-m. We determined the in vitro antiproliferative activities of compounds 2, 5, 3a-m and 6a-m by means of MTT assays on a panel of human adherent cancer cell lines A2780, MCF-7, MB-231 and SiHa.

Isolation and Pharmacological Investigation of Compounds From Euphorbia matabelensis

This work deals with the isolation and pharmacological investigations of compounds of Euphorbia matabelensis. After multiple separation process, including thin layer chromatography (TLC), vacuum liquid chromatography, preparative TLC, and high-performance liquid chromatography, 1 diterpene (ingenol) and 2 flavonoids (naringenin and eriodictyol) were obtained from the methanol extracts prepared from the stems and roots of the plant. The structures of the isolated compounds were determined by nuclear magnetic resonance (NMR) and MS measurements and comparison with literature data. All compounds were isolated for the first time from the plant. Eriodictyol was detected for the first time from a Euphorbia species. The compounds were tested for their antiproliferative (on HeLa, C33a, MCF-7, and MDA-MB-231 cell lines) and GIRK channel blocking activities. None of the compounds proved to be active in these test systems.

Anti-Cancer Activity of Novel Dihydrotestosterone-Derived Ring A-Condensed Pyrazoles on Androgen Non-Responsive Prostate Cancer Cell Lines

Regioselective synthesis of novel ring A-fused arylpyrazoles of dihydrotestosterone (DHT) was carried out in two steps under facile reaction conditions. Aldol condensation of DHT with acetaldehyde afforded a 2-ethylidene derivative regio- and stereo-selectively, which was reacted with different arylhydrazines in the presence of iodine via microwave-assisted oxidative cyclization reactions. The 17-keto analogs of steroidal pyrazoles were also synthesized by simple oxidation in order to enlarge the compound library available for pharmacological studies and to obtain structure–activity relationship. The antiproliferative activities of the structurally related heteroaromatic compounds were tested in vitro on human cervical and breast adenocarcinoma cell lines (HeLa, MCF-7 and MDA-MB-231) and on two androgen-independent malignant prostate carcinoma cell lines (PC-3 and DU 145). Based on primary cytotoxicity screens and IC₅₀ assessment, a structure-function relationship was identified, as derivatives carrying a hydroxyl group on C-17 exhibit stronger activity compared to the 17-one counterparts. Cancer cell selectivity of the derivatives was also determined using non-cancerous MRC-5 cells. Furthermore, the proapoptotic effects of some selected derivatives were verified on androgen therapy refractive p53-deficient PC-3 cells. The present study concludes that novel DHT-derived arylpyrazoles exert cancer cell specific antiproliferative activity and activate apoptosis in PC-3 cells.