Modification of the Cp′ ring in the ferrocifen precursor and its influence on the recognition by the estrogen receptor

A synthetic pathway giving access to diphenyl ethylene organometallic derivatives possessing the ferrocifen precursor skeleton modified in the Cp′ ring is described. It relies on reaction of the (η⁵-propionylcyclopentadienyl) (η⁶-benzene)iron(II) salt 7 with substituted cyclopentadienyl anions or their heteroanalogs followed by the McMurry coupling reaction with 4,4′-dihydroxybenzophenone. Using this approach pentamethylcyclopentadienyl and 3,4-dimethylphospholyl analogs of ferrocifen precursor (10 and 11) have been synthesized. Even with the presence of the bulky and containing phosphorus η⁵-ligands these compounds are still recognized by the two subtypes of estrogen receptor(ERα and ERβ).     

Organometallic SERMs (selective estrogen receptor modulators): Cobaltifens, the (cyclobutadiene)cobalt analogues of hydroxytamoxifen

The McMurry coupling of (tetraphenylcyclobutadiene)cobalt(cyclopentadienyl) ketones, (C₄Ph₄)Co[C₅H₄C(O)R], where R = Me, 3a, or Et, 3b, with a range of substituted benzophenones furnished a series of cobaltifens, organometallic analogues of tamoxifen whereby a phenyl ring has been replaced by an organo-cobalt sandwich moiety. These systems of the general formula (η⁴-C₄Ph₄)Co[η⁵-C₅H₄C(R)C(Ar)Ar′], where R = Me or Et, and Ar = Ar′ = p-C₆H₄X where X is OH, 2a and 2b, OMe, 2c and 2d, OBn, 2e and 2f, or O(CH₂)₂NMe₂, 12a and 12b, and where Ar = C₆H₄OH and Ar′ = C₆H₄O(CH₂)₂NMe₂, 2g and 2h, have been characterised by NMR spectroscopy and/or X-ray crystallography. The effect of 2a and 2b, 2g and 2h, and 12a and 12b on the growth of MCF-7 (hormone-dependent) and MDA-MB-231 (hormone-independent breast cancer cells) was studied. The dihydroxycobaltifens 2a and 2b exhibit a strong estrogenic effect on MCF-7 cells while the aminoalkyl-hydroxycobaltifens, 2g and 2h, were found to be only slightly cytotoxic on MDA-MB-231 cells (IC₅₀ = 27.5 and 17 μM); surprisingly, however, the bis-(dimethylaminoethoxy)cobaltifens, 12a and 12b were shown to be highly cytotoxic towards both cell lines (IC₅₀ = 3.8 and 2.5 μM).     

Piperidine Nucleophilic Substitution Without Solvent: An Efficient Synthesis of Raloxifene

Mild and high-yielding synthesis is described for raloxifene via piperdine nucleophilic substitution of a new raloxifene intermediate 3-aroyl-2-aryl-substituted benzo[b]thiophenes, which is obtained by acylation of para-substituted benzoyl chlorides and 2-arylbenzo[b]thiophenes. The key step is solvent free and offers valuable advantages, such as low cost, and is suitable for industrial production.     

A new approach to desketoraloxifene analogs from oxygen-bearing 3-iodobenzo[b]thiophenes prepared via iodocyclization

A formal total synthesis of the benzothiophene selective estrogen receptor modulator (SERM) desketoraloxifene and analogs has been accomplished from alkynes bearing electron-rich aromatic rings by electrophilic cyclization using I₂. This approach affords oxygen-bearing 3-iodobenzo[b]thiophenes in excellent yields, which are easily further elaborated using a two-step approach involving Suzuki-Miyaura and Mitsunobu coupling reactions.     

具有选择性雌激素受体调节活性的大豆苷元衍生物的合成及生物活性研究

以大豆苷元为母体,取代氨基烷氧基为侧链,设计、合成了28个结构耨颖的未见文献报道的大豆苷元衍生物,并检测了其对雌激素受体阳性的人乳腺癌细胞株MCF-7的体外活性.结果表明,化合物4c,4g及6a对MCF-7的增殖有显著的抑制作用,48,72 h的抑制率均大于50％(p＜0.01).化合物11h具有显著的促进MCF-7细胞增殖的作用,48,72h的增殖率均大于20％(P＜0.05);化合物10a作用48 h时对MCF-7细胞的增殖有显著的促进作用,增殖率大于10％(p＜0.05).     

Selenium Analogue of LSZ102 as a Highly Potent ER-α Binder

Nowadays, selective estrogen receptor modulators (SERMs) and downregulators (SERDs) are used as the first-line medical treatment for estrogen receptor positive (ER+) tumors. Herein we report synthesis, ER-α binding activity, and cytotoxicity of LSZ102 selenium analogues 11 and 28 . TR-FRET competitive ER-α binding experiments and cytotoxicity assays have shown that the selenium analogues exhibit closely related activity to LSZ102. Furthermore, the prepared selenium analogues are not toxic in rat cardiomyoblasts (H9C2), indicating that substituted benzo[b]selenophene is a prospective scaffold for the development of ER-α modulators and downregulators for the treatment of ER+ cancers.     

Organometallic analogues of tamoxifen: Effect of the amino side-chain replacement by a carbonyl ferrocenyl moiety in hydroxytamoxifen

Since the widely prescribed selective estrogen receptor modulator (SERM) tamoxifen encounters growing cases of resistance in long-term treatments, alternative drugs with different therapeutic scopes have to be developed. Many investigators have modified the triphenylethylene scaffold, but very few have changed its amino side chain, essential for the antiestrogenic activity. For the first time, a lipophilic and stable organometallic entity, -OCH₂CO-[(η⁵-C₅H₄)FeCp], has replaced this key functional side chain, while keeping a good affinity for the estrogen receptor and an antiproliferative activity on cancer cells (MCF-7 and PC-3). Its mechanism of action is likely to be different from the antihormonal pathway followed by hydroxytamoxifen, and from the cytotoxicity observed for the ferrocifens.     

Towards Unravelling the Role of ERα-Targeting miRNAs in the Exosome-Mediated Transferring of the Hormone Resistance

Hormone therapy is one of the most effective breast cancer treatments, however, its application is limited by the progression of hormonal resistance, both primary or acquired. The development of hormonal resistance is caused either by an irreversible block of hormonal signalling (suppression of the activity or synthesis of hormone receptors), or by activation of oestrogen-independent signalling pathways. Recently the effect of exosome-mediated intercellular transfer of hormonal resistance was revealed, however, the molecular mechanism of this effect is still unknown. Here, the role of exosomal miRNAs (microRNAs) in the transferring of hormonal resistance in breast cancer cells has been studied. The methods used in the work include extraction, purification and RNAseq of miRNAs, transfection of miRNA mimetics, immunoblotting, reporter analysis and the MTT test. Using MCF7 breast cancer cells and MCF7/T tamoxifen-resistant sub-line, we have found that some miRNAs, suppressors of oestrogen receptor signalling, are overexpressed in the exosomes of the resistant breast cancer cells. The multiple (but not single) transfection of one of the identified miRNA, miR-181a-2, into oestrogen-dependent MCF7 cells induced the irreversible tamoxifen resistance associated with the continuous block of the oestrogen receptor signalling and the activation of PI3K/Akt pathway. We suppose that the miRNAs-ERα suppressors may act as trigger agents inducing the block of oestrogen receptor signalling and breast cancer cell transition to an aggressive oestrogen-independent state.     

Synthesis of 11β-ether-17α-ethinyl-3,17β-estradiols with strong ER antagonist activities

We have previously found that several families of nonpolar short chain 11 β-ethers and esters of estradiol are selective estrogen receptor modulators(SERMs).Surprisingly,the transformation from potent estrogen to anti-estrogen occurs when the 11β-side chain is increased slightly in length from four to five non-hydrogen atoms.To generate strong antagonists for preclinical development,we have synthesized other similar ER ligands with 11β-ethers and with an additional ethinyl group at the 17α-position in order to slow metabolism of the steroidal moiety.Here we report the synthesis and biological activity of two such compounds(11β-i-PrO-propyl and 11β-t-BuO-propyl ethers) with extremely strong antagonist activities.