Investigation of the Antineoplastic Effects of 2-(4-Chlorophenyl)-13α-Estrone Sulfamate against the HPV16-Positive Human Invasive Cervical Carcinoma Cell Line SiHa.

Cervical carcinoma is one of the most frequent malignant gynecological cancers in women of reproductive age. Because of the poor tolerability of currently available chemotherapeutic agents, efforts have been focused on developing innovative molecules, including steroids, that exert antineoplastic effects with a better safety profile. In addition to their endocrine properties, certain estrogens exhibit additional biological activities, such as antiangiogenic and anticancer effects. Based on previous studies, the antineoplastic properties of 13α-estrone sulfamate derivatives (13AES1-3) were investigated, and the mechanism of action for the most promising compound 13AES3 was explored. Based on their effects on the viability of different human adherent gynecological cancer cells, the SiHa cervical cell line was used for mechanistic experiments. The most active analog 13AES3 was shown to exert considerable proapoptotic effects, as evidenced by a colorimetric caspase-3 assay and fluorescent double staining. It also elicited antimigratory and anti-invasive effects in a concentration-dependent manner, as evidenced by wound healing and Boyden chamber assays, respectively. Regarding their mechanism of action, 13AES derivatives were shown to inhibit tubulin polymerization, and computer simulations provided a possible explanation for the importance of the presence of the chlorophenyl ring on the estrane skeleton. 13AES3 is considered to be the first 13α-estrone derivative with a significant antineoplastic potency against SiHa cancer cells. Therefore, it might serve as a valuable lead molecule for the design of anticancer agents targeting cervical carcinomas.

Synthesis and Antiproliferative Activity of Steroidal Diaryl Ethers.

Novel 13α-estrone derivatives have been synthesized via direct arylation of the phenolic hydroxy function. Chan-Lam couplings of arylboronic acids with 13α-estrone as a nucleophilic partner were carried out under copper catalysis. The antiproliferative activities of the newly synthesized diaryl ethers against a panel of human cancer cell lines (A2780, MCF-7, MDA-MB 231, HeLa, SiHa) were investigated by means of MTT assays. The quinoline derivative displayed substantial antiproliferative activity against MCF-7 and HeLa cell lines with low micromolar IC50 values. Disturbance of tubulin polymerization has been confirmed by microplate-based photometric assay. Computational calculations reveal significant interactions of the quinoline derivative with the taxoid binding site of tubulin.

Transition metal-catalysed A-ring C-H activations and C(sp2)-C(sp2) couplings in the 13α-oestrone series and in vitro evaluation of antiproliferative properties.

Facile syntheses of 3-O-carbamoyl, -sulfamoyl, or -pivaloyl derivatives of 13α-oestrone and its 17-deoxy counterpart have been carried out. Microwave-induced, Ni-catalysed Suzuki-Miyaura couplings of the newly synthesised phenol esters with phenylboronic acid afforded 3-deoxy-3-phenyl-13α-oestrone derivatives. The carbamate and pivalate esters proved to be suitable for regioselective arylations. 2-(4-Substituted) phenyl derivatives were synthesised via Pd-catalysed, microwave-assisted C-H activation reactions. An efficient, one-pot, tandem methodology was elaborated for the introduction of the carbamoyl or pivaloyl group followed by regioselective C-2-arylation and subsequent removal of the directing group. The antiproliferative properties of the novel 13α-oestrone derivatives were evaluated in vitro on five human adherent cancer cell lines of gynaecological origin. 3-Sulfamate derivatives displayed substantial cell growth inhibitory potential against certain cell lines. The newly identified antiproliferative compounds having hormonally inactive core might be promising candidates for the design of more active anticancer agents.

Synthesis, Biological Evaluation and Docking Studies of 13-Epimeric 10-fluoro- and 10-Chloroestra-1,4-dien-3-ones as Potential Aromatase Inhibitors.

Fluorination of 13-epimeric estrones and their 17-deoxy counterparts was performed with Selectfluor as the reagent. In acetonitrile or trifluoroacetic acid (TFA), 10ß-fluoroestra-1,4-dien-3-ones were formed exclusively. Mechanistic investigations suggest that fluorinations occurred via SET in acetonitrile, but another mechanism was operative in TFA. Simultaneous application of N-chlorosuccinimide (NCS) and Selectfluor in TFA led to a 1.3:1 mixture of 10ß-fluoroestra-1,4-dien-3-one and 10ß-chloroestra-1,4-dien-3-one as the main products. The potential inhibitory action of the 10-fluoro- or 10-chloroestra-1,4-dien-3-one products on human aromatase was investigated via in vitro radiosubstrate incubation. The classical estrane conformation with trans ring anellations and a 13ß-methyl group seems to be crucial for the inhibition of the enzyme, while test compounds bearing the 13ß-methyl group exclusively displayed potent inhibitory action with submicromolar or micromolar IC50 values. Concerning molecular level explanation of biological activity or inactivity, computational simulations were performed. Docking studies reinforced that besides the well-known Met374 H-bond connection, the stereocenter in the 13 position has an important role in the binding affinity. The configuration inversion at C-13 results in weaker binding of 13α-estrone derivatives to the aromatase enzyme.