Antiproliferative effect of normal and 13-epi-D-homoestrone and their 3-methyl ethers on human reproductive cancer cell lines

In Vitro Pharmacological Activity, and Comparison GC-ToF-MS Profiling of Extracts from Cissus cornifolia (Baker) Planch

Cissus cornifolia (Baker) Planch is traditionally used in South African traditional medicine (SATM) to treat a variety of human infections. The antimicrobial activity of extracts from C. cornifolia was investigated in vitro against a plethora of pathogenic microorganisms using the microdilution assay. The acetone extract exhibited a notable minimum inhibitory concentration (MIC) value of 0.10 mg/mL against Mycoplasma hominis and a further MIC of 0.20 mg/mL against Candida parapsilosis, Streptococcus agalactiae, Pseudomonas aeruginosa, and Enterococcus faecalis. In the antiproliferative assays, both the ethyl acetate and methanol extracts exhibited a potent inhibition of the MCF-7-21 cell line. In the anti-inflammatory assays, both the ethyl acetate and methanol extracts exhibited IC₅₀ values of 15.59 and 15.78 µg/mL against Cyclooxygenase-2 (COX-2), respectively. Methanol extract further exhibited potent dual inhibition of both COX-2 and 15-LOX enzymes, hence, recommended to curb both related cancers, particularly breast cancer and inflammation-borne diseases. In the comparative gas chromatography time-of-flight mass spectrometry (GC/TOF-MS), the acetone, ethyl acetate, and methanol extract contained significantly prevalent amounts of compound 2-(2',4',4',6',6',8',8'-Heptamethyltetrasiloxan-2'-yloxy)-2,4,4,6,6,8,8,10,10-nonamethylcyclopentasiloxane with % area ranging from 15.714 to 39.225. The findings in the current work validates the use of the plant species in SATM in the treatment of cancer-like infections, opportunistic infections associated with HIV-AIDS. Furthermore, the in vivo studies and the mechanisms of action still need to be explored.

Heterocyclic androstane and estrane d-ring modified steroids: Microwave-assisted synthesis, steroid-converting enzyme inhibition, apoptosis induction, and effects on genes encoding estrogen inactivating enzymes

d-ring-fused and d-homo lactone compounds in estratriene and androstane series were synthesized using microwave-assisted reaction conditions. Microwave-irradiated synthesis methods were convenient and effective, and provided high yields with short reaction times. Their inhibition of C_17,20-lyase and 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) activities were studied in in vitro enzyme assays. d-ring-fused triazolyl estrone analog 24 showed potent inhibition of NADH-complexed 17β-HSD1, with a binding affinity similar to that of the substrate estrone; its inhibition against NADPH-complexed 17β-HSD1 was markedly weaker. Compound 24 also significantly and selectively reduced proliferation of cancer cell lines of gynecological origin. This estrane triazole changed the cell cycle and induced apoptosis of HeLa, SiHa, and MDA-MB-231 cancer cells, measured by both increased subG1 fraction of cells and activation of caspase-independent signaling pathways. A third mode of anti-estrogenic action of 24 saw increased mRNA expression of the SULT1E1 gene in HeLa cells; in contrast, its 3-benzyloxy analog 23 increased mRNA expression of the HSD17B2 gene, thus showing pronounced pro-drug anti-estrogenic activity. Estradiol-derived d-ring triazole compound 24 thus acts at the enzyme, gene expression and cellular levels to decrease the production of active estrogen hormones, demonstrating its pharmacological potential.

Potent Anti-Ovarian Cancer with Inhibitor Activities on both Topoisomerase II and V600EBRAF of Synthesized Substituted Estrone Candidates

A series of 16-(α-alkoxyalkane)-17-hydrazino-estra-1(10),2,4-trien[17,16-c]-3-ol (3a-l) and estra-1(10),2,4-trien-[17,16-c]pyrazoline-3-ol derivatives (4a-d) were synthesized from corresponding arylidines 2a,b which was prepared from estrone 1 as starting material. Condensation of 1 with aldehydes gave the corresponding arylidine derivatives 2a,b which were treated with hydrazine derivatives in alcohols to give the corresponding derivatives 3a-l, respectively. Additionally, treatment of 2a,b with methyl- or phenylhydrazine in ethanolic potassium hydroxide afforded the corresponding N-substituted pyrazoline derivatives 4a-d, respectively. All these derivatives showed potent anti-ovarian cancer both in vitro and in vivo. The mechanism of anti-ovarian cancer was suggested to process via topoisomerase II and V600EBRAF inhibition.

Design and Synthesis of Novel Dehydroepiandrosterone Analogues as Potent Antiproliferative Agents

The aim of the present study was to determine the cytotoxic effects of a series of novel dehydroepiandrosterone derivatives containing triazole at the C₁₆ position on human cancer cells. The cancer cells used in the present study were A549, Hela, HepG-2, BEL7402, MCF-7, and HCT116. Several of the synthesised compounds exhibited potent antiproliferative effects. The most promising compound was (E)-3-hydroxy-16-((1-(4-iodophenyl)-1H-1,2,3-triazole-4-yl)methylene)-10,13-dimet-hyl-1,3,4,7,8,9,10,11,12,13,15,16-dodecahydro-2H-cyclopenta[a]phenanthren-17(14)-one (compound 2n), which showed considerably high antiproliferative activity in the HepG-2 cell line, with an IC₅₀ value of 9.10 µM, and considerably high activity against the MCF-7 cell line, with an IC₅₀ value of 9.18 µM. Flow cytometry assays demonstrated that compound 2n exerted antiproliferative effects by arresting cells in the G2 phase of the cell cycle and inducing apoptosis.

3,20-Dihydroxy-13α-19-norpregna-1,3,5(10)-trienes. Synthesis, structures, and cytotoxic, estrogenic, and antiestrogenic effects

New 3,20-dihydroxy-13α-19-norpregna-1,3,5(10)-trienes were synthesized. The effects of these compounds on breast cancer cells and ERα activation were investigated. The scaffold of compounds containing the six-membered ring D' annulated at 16α,17α-positions was constructed via the Lewis acid catalyzed Diels-Alder reaction of butadiene with 3-methoxy-13α-19-norpregna-1,3,5(10),16-tetraen-20-one 5 under a pressure of 600 MPa. The hydrogenation of primary cyclohexene adduct 6 followed by the one-pot reduction-demethylation (DIBAH) gave target epimeric 3,20-dihydroxy steroids 8a and 8b. The Corey-Chaykovsky reaction of the same conjugated ketone 5 gave a 16α,17α-methylene-substituted compound. The reaction of the latter with DIBAH yielded 3,20(R,S)-dihydroxy-16α,17α-methyleno-13α-19-norpregna-1,3,5(10)-triene 10. The hydrogenation of the 16,17-double bond of compound 5 produced a mixture of 17α- and 17β-epimeric ketones, reduction-demethylation of which gave 3,20(S)-dihydroxy-13α,17α-19-norpregna-1,3,5(10)-triene 12a and 3,20(R)-dihydroxy-13α,17β-19-norpregna-1,3,5(10)-triene 12b. All compounds were fully characterized by 1D and 2D NMR, HRMS, and X-ray diffraction. All target compounds showed pronounced cytotoxic effect against MCF-7 breast cancer cells and NCI/ADR-RES doxorubicin-resistant cells at micromolar concentrations. The ERα-mediated luciferase reporter gene assay demonstrated that all compounds, except for compound 10, are ERα inhibitors, while cyclopropane compound 10 proved to be an ERα activator. Docking experiments showed that all compounds are well accommodated to LBD ERα but have some differences in the binding mode.

In Vitro and In Vivo Anti-Breast Cancer Activities of Some Synthesized Pyrazolinyl-estran-17-one Candidates

A series of estrone derivatives, 2–4, were synthesized from the corresponding arylidine estrone, 2a,b, as starting materials, which were prepared by condensation of estrone (3-hydroxy-estran-17-one, 1) with 4-bromobenzaldehyde and thiophene-2-aldehyde. Treating of 2a,b with hydrazine derivatives in acetic acid or propionic acid afforded pyrazoline derivatives, 3a–f and 4a–f, respectively. Furthermore, results proved the superiority of thienyl derivatives over 4-bromophenol derivatives in terms of cytotoxic effects on MCF-7 cancer cells. In vivo xenograft breast cancer animal model experiments revealed that the synthesized derivatives can be used for decreasing tumor volume, while the most potent derivative (4f) decreased the development of tumor volume by about 87.0% after 12 days.

Stereoselective synthesis of the four 16-hydroxymethyl-3-methoxy- and 16-hydroxymethyl-3-benzyloxy-13α-estra-1,3,5(10)-trien-17-ol isomers and their antiproliferative activities

The reduction of 16-hydroxymethylene-3-methoxy-13α-estra-1,3,5(10)-trien-17-one (14) and 16-hydroxymethylene-3-benzyloxy-13α-estra-1,3,5(10)-trien-17-one (16) yielded a mixture of two diastereomeric diols, the 16α-hydroxymethyl,17β-hydroxy and 16β-hydroxymethyl,17α-hydroxy isomers (17a-20a) in a ratio of 6:1. We describe a straightforward synthetic route to transform the isomers with trans functional groups attached to ring D (17a-20a) into isomers with cis functional groups (25a-28a). We determined the in vitro antiproliferative activities of compounds 17a-20a and 25a-28a by means of MTT assays against a panel of human adherent cancer cell lines HeLa, A2780, MCF-7, T47D, MDA-MB-231 and MDA-MB-361.

Synthesis of novel 13α-estrone derivatives by Sonogashira coupling as potential 17β-HSD1 inhibitors

Novel 13α-estrone derivatives were synthesized by Sonogashira coupling. Transformations of 2- or 4-iodo regioisomers of 13α-estrone and its 3-methyl ether were carried out under different conditions in a microwave reactor. The 2-iodo isomers were reacted with para-substituted phenylacetylenes using Pd(PPh₃)₄ as catalyst and CuI as a cocatalyst. Coupling reactions of 4-iodo derivatives could be achieved by changing the catalyst to Pd(PPh₃)₂Cl₂. The product phenethynyl derivatives were partially or fully saturated. Compounds bearing a phenolic OH group furnished benzofurans under the conditions used for the partial saturation. The inhibitory effects of the compounds on human placental 17β-hydroxysteroid dehydrogenase type 1 isozyme (17β-HSD1) were investigated by an in vitro radiosubstrate incubation method. Certain 3-hydroxy-2-phenethynyl or -phenethyl derivatives proved to be potent 17β-HSD1 inhibitors, displaying submicromolar IC₅₀ values.

Mechanism of antiproliferative action of a new d-secoestrone-triazole derivative in cervical cancer cells and its effect on cancer cell motility

Cervical cancer is the fourth most frequently diagnosed tumor and the fourth leading cause of cancer death in females worldwide. Cervical cancer is predominantly related with human papilloma virus (HPV) infection, with the most oncogenic types being HPV-18 and -16. Our previous studies demonstrated that some d-secoestrone derivatives exert pronounced antiproliferative activity. The aim of the current investigation was to characterize the mechanism of action of d-secoestrone-triazole (D-SET) on three cervical cancer cell lines with different pathological backgrounds. The growth-inhibitory effects of D-SET were determined by a standard MTT assay. We have found that D-SET exerts a pronounced growth-inhibitory effect on HPV 18-positive HeLa and HPV-negative C-33 A cells, but it has no substantial inhibitory activity on HPV 16-positive SiHa or on intact fibroblast MRC-5 cell lines. After 24h incubation, cells showed the morphological and biochemical signs of apoptosis determined by fluorescent double staining, flow cytometry and caspase-3 activity assay. Besides the elevation of the ratio of cells in the subG1 phase, flow cytometric analysis revealed a cell cycle arrest at G2/M in both HeLa and C-33 A cell lines. To distinguish the G2/M cell population immunocytochemical flow cytometric analysis was performed on HeLa cells. The results show that D-SET significantly increases the ratio of phosphorylated histone H3, indicating cell accumulation in the M phase. Additionally, D-SET significantly increased the maximum rate of microtube formation measured by an in vitro tubulin polymerization assay. Besides its direct antiproliferative activity, the antimigratory property of D-SET has been investigated. Our results demonstrate that D-SET significantly inhibits the migration and invasion of HeLa cells after 24h incubation. These results suggests that D-SET is a potent antiproliferative agent against HPV 16+ and HPV-negative cervical cancer cell lines, with an efficacious motility-inhibiting activity against HPV 16+ cells. Accordingly D-SET can be regarded as a potential drug candidate with a promising new mechanism of action among the antiproliferative steroids, potentially allowing for the design of novel anticancer agents.

Synthesis and Biological Evaluation of Triazolyl 13α-Estrone-Nucleoside Bioconjugates

2′-Deoxynucleoside conjugates of 13α-estrone were synthesized by applying the copper-catalyzed alkyne–azide click reaction (CuAAC). For the introduction of the azido group the 5′-position of the nucleosides and a propargyl ether functional group on the 3-hydroxy group of 13α-estrone were chosen. The best yields were realized in our hands when the 3′-hydroxy groups of the nucleosides were protected by acetyl groups and the 5′-hydroxy groups were modified by the tosyl–azide exchange method. The commonly used conditions for click reaction between the protected-5′-azidonucleosides and the steroid alkyne was slightly modified by using 1.5 equivalent of Cu(I) catalyst. All the prepared conjugates were evaluated in vitro by means of MTT assays for antiproliferative activity against a panel of human adherent cell lines (HeLa, MCF-7 and A2780) and the potential inhibitory activity of the new conjugates on human 17β-hydroxysteroid dehydrogenase 1 (17β-HSD1) was investigated via in vitro radiosubstrate incubation. Some protected conjugates displayed moderate antiproliferative properties against a panel of human adherent cancer cell lines (the protected cytidine conjugate proved to be the most potent with IC₅₀ value of 9 μM). The thymidine conjugate displayed considerable 17β-HSD1 inhibitory activity (IC₅₀ = 19 μM).

Synthesis and biological evaluation of 13α-estrone derivatives as potential antiproliferative agents

13α-Estrone derivatives containing various substituents on C-3 and C-17 were synthesized, and evaluated by means of MTT assays for in vitro antiproliferative activity against a panel of human adherent cancer cell lines (HeLa, MCF-7, A2780 and A431). Compounds with N-benzyltriazolylmethoxy moieties on C-3 proved to be more potent than their 3-hydroxy or 3-ether counterparts. Some triazoles exerted substantial cytostatic effects against particular tumor cell lines, with submicromolar IC50 values.

Synthesis and biological activity of two pregnane derivatives with a triazole or imidazole ring at C-21

Pregnane derivatives are studied as agents for the treatment of different hormone-dependent diseases. The biological importance of these steroids is based on their potential use against cancer. In this study, we report the synthesis, characterization and biological activity of two pregnane derivatives with a triazole (3β-hydroxy-21-(1H-1,2,4-triazol-1-yl)pregna-5,16-dien-20-one; T-OH) or imidazole (3β-hydroxy-21-(1H-imidazol-1-yl)pregna-5,16-dien-20-one; I-OH) moieties at C-21. These derivatives were synthesized from 16-dehydropregnenolone acetate. The activity on cell proliferation of the compounds was measured on three human cancer cells lines: prostate cancer (PC-3), breast cancer (MCF7) and lung cancer (SK-LU-1). The cytotoxic and antiproliferative effects of T-OH and I-OH were assessed by using SBR and XTT methods, respectively. The gene expressions were evaluated by real time PCR. In addition, results were complemented by docking studies and transactivation assays using an expression vector to progesterone and androgen receptor. Results show that the two compounds inhibited the three cell lines proliferation in a dose-dependent manner. Compound I-OH downregulated the gene expression of the cyclins D1 and E1 in PC-3 and MFC7 cells; however, effect upon Ki-67, EAG1, BIM or survivin genes was not observed. Docking studies show poor interaction with the steroid receptors. Nevertheless, the transactivation assays show a weak antagonist effect of I-OH on progesterone receptor but not androgenic or antiandrogenic actions. In conclusion, the synthesized compounds inhibited cell proliferation as well as genes key to cell cycle of PC-3 and MCF7 cell lines. Therefore, these compounds could be considered a good starting point for the development of novel therapeutic alternatives to treat cancer.

Synthesis of A-ring halogenated 13α-estrone derivatives as potential 17β-HSD1 inhibitors

13α-Estrone and its 3-methyl or benzyl ether were halogenated in ring A with N-bromo- or N-iodosuccinimide or 1,3-dibromo-5,5-dimethylhydantoin as electrophile triggers. The chemo- and regioselectivities of the reactions depended greatly on the nature of the substituent on C-3. Bromination of the ethers led to 2- and 4-regioisomers. Bis-halogenation occurred only in the case of the phenolic derivative. Iodination and bromination resulted in similar products, except that the 3-benzyl ether could not be iodinated under the applied conditions. The potential inhibitory action of the new halogenated 13α-estrones on human 17β-hydroxysteroid dehydrogenase 1 activity was investigated via in vitro radiosubstrate incubation. Some compounds proved to be effective inhibitors, with IC50 values in the submicromolar range.

Synthesis of antiproliferative 13α-d-homoestrones via Lewis acid-promoted one-pot Prins-Ritter reactions of d-secosteroidal δ-alkenyl-aldehydes

A simple one-pot Prins-Ritter route was developed for the synthesis of 16-acylamino-17a-hydroxy-d-homoestrone 3-benzyl and 3-methyl ethers in the 13α-estrone series. The d-secosteroidal δ-alkenyl-aldehydes were allowed to react with different nitriles in the presence of BF3·OEt2 as a Lewis acid catalyst. Prins cyclizations afforded 17a-hydroxy-16-carbenium ions, which underwent Ritter reactions with nitriles, leading to 16α- or 16β-acylamino derivatives. A side-product in which a dihydro-1,3-oxazine was bridged to six-membered ring D at positions 16α,17aα was formed in each reaction. The antiproliferative properties of the novel 13α-d-homosteroids were determined on a panel of human adherent cancer cell lines (HeLa, MCF-7, T47D, MDA-MB-231, MDA-MB-361, A2780 and A431) by means of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays. Some compounds proved to be more effective (with submicromolar IC50 values) than the reference agent cisplatin. One of the most potent compounds substantially increased the rate of tubulin polymerization. Cell cycle analyses by flow cytometry indicated a concentration-dependent accumulation of the G2/M cell population.

Synthesis and in vitro pharmacological evaluation of N-[(1-benzyl-1,2,3-triazol-4-yl)methyl]-carboxamides on d-secoestrone scaffolds

An efficient synthesis of several N-[(1-benzyl-1,2,3-triazol-4-yl)methyl]carboxamides in the 13β- and 13α-d-secoestrone series is reported. Novel triazoles were synthesized via the Cu(I)-catalyzed azide-alkyne cycloaddition of steroidal alkynyl carboxamides and p-substituted benzyl azides. Each of the products was evaluated in vitro by means of MTT assays for antiproliferative activity against a panel of human adherent cancer cell lines (HeLa, MCF-7, A431 and A2780). Some of them exhibited activities similar to those of the reference agent cisplatin. On change of the substitution pattern of the benzyl group of the azide, great differences in the cell growth-inhibitory properties were observed. The p-alkylbenzyl-substituted triazoles selectively exerted high cytostatic action against A2780 cells, with IC50 values of 1 µM. We investigated the potential inhibitory action exerted on the human 17β-HSD1 activity of the new secosteroids. Three triazoles effectively suppressed the estrone to 17β-estradiol conversion with IC50 values in low micromolar range.

A molecular understanding of D-homoestrone-induced G2/M cell cycle arrest in HeLa human cervical carcinoma cells

2-Methoxyestradiol (ME), one of the most widely investigated A-ring-modified metabolites of estrone, exerts significant anticancer activity on numerous cancer cell lines. Its pharmacological actions, including cell cycle arrest, microtubule disruption and pro-apoptotic activity, have already been described in detail. The currently tested d-ring-modified analogue of estrone, d-homoestrone, selectively inhibits cervical cancer cell proliferation and induces a G2/M phase cell cycle blockade, resulting in the development of apoptosis. The question arose of whether the difference in the chemical structures of these analogues can influence the mechanism of anticancer action. The aim of the present study was therefore to elucidate the molecular contributors of intracellular processes induced by d-homoestrone in HeLa cells. Apoptosis triggered by d-homoestrone develops through activation of the intrinsic pathway, as demonstrated by determination of the activities of caspase-8 and -9. It was revealed that d-homoestrone-treated HeLa cells are not able to enter mitosis because the cyclin-dependent kinase 1-cyclin B complex loses its activity, resulting in the decreased inactivation of stathmin and a concomitant disturbance of microtubule formation. However, unlike 2-ME, d-homoestrone does not exert a direct effect on tubulin polymerization. These results led to the conclusion that the d-homoestrone-triggered intracellular processes resulting in a cell cycle arrest and apoptosis in HeLa cells differ from those in the case of 2-ME. This may be regarded as an alternative mechanism of action among steroidal anticancer compounds.

Synthesis of trans-16-triazolyl-13α-methyl-17-estradiol diastereomers and the effects of structural modifications on their in vitro antiproliferative activities

Novel 16-triazoles in the 13α-estrone series were synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition of the two diastereomeric (on C-16 and on C-17) 16-azido-13α-estra-1,3,5(10)-trien-17-ol 3-benzyl ethers with substituted phenylacetylenes. The new heterocyclic derivatives were evaluated in vitro by means of MTT assays for antiproliferative activity against a panel of human adherent cancer cell lines (HeLa, MCF-7, A431, A2780, T47D, MDA-MB-231 and MDA-MB-361). The inversion of the configurations at C-16 and C-17 selectively affected the growth-inhibitory properties of the tested compounds. The 16β,17α isomers generally proved to be potent on all cell lines, with IC50 values comparable to those of the reference agent cisplatin. Change of the substitution pattern of the phenyl group of the acetylene led to great differences in antiproliferative properties. Exclusively the p-phenyl-substituted triazoles exerted high cytostatic effects. One of the most potent compounds activated caspase-3 and caspase-9 without influencing caspase-8, confirming the induction of apoptosis via the intrinsic pathway.

Syntheses and antiproliferative effects of D-homo- and D-secoestrones

Substituted and/or heterocyclic d-homoestrone derivatives were synthetized via the intramolecular cyclization of a δ-alkenyl-d-secoaldehyde, -d-secoalcohol or -d-secocarboxylic acid of estrone 3-benzyl ether. The d-secoalcohol was modified at three sites in the molecule. The in vitro antiproliferative activities of the new d-homo- and d-secoestrone derivatives were determined on HeLa, MCF-7, A431 and A2780 cells through use of MTT assay. d-Homoalcohols 3 and 5 displayed cell line-selective cytostatic effects against ovarian and cervical cell lines, respectively. Two d-secoestrones (6 and 12c) proved to be effective, with IC50 values comparable with those of the reference agent cisplatin. A selected compound (6) was tested by tubulin polymerization assay and its cancer specificity was additionally determined by using noncancerous human fibroblast cells.

Cycloaddition of steroidal cyclic nitrones to C=N dipolarophiles: stereoselective synthesis and antiproliferative effects of oxadiazolidinones in the estrone series

Cyclic nitrones of estrone 3-methyl or 3-benzyl ether were reacted with phenyl isocyanate or nonsubstituted phenyl isocyanates as reactive CN dipolarophiles, yielding condensed homosteroidal oxadiazolidinones. These dipolar cycloadditions were carried out under conventional heating or microwave irradiation. The chemo- and stereoselectivities of the reactions and the effects of the aromatic substituents on the reaction rates and yields were investigated and compared. The structures of the new products were determined by NMR (one- and two-dimensional) and MALDI-MS techniques, with C70 fullerenes as matrix in the latter case. The antiproliferative properties of the synthetized compounds were determined on a panel of human adherent cell lines (HeLa, MCF7, A2780 and A431) by means of MTT assays. Some of them exhibited activities comparable to that of the reference agent cisplatin. Flow cytometry indicated that one of the most potent agents (11a) resulted in a cell cycle blockade.

Synthesis of sex hormone-derived modified steroids possessing antiproliferative activity

During recent years intensive research has been focused on the synthesis of structurally modified steroid hormones in order to obtain compounds with beneficial biological activity such as cell-growth inhibition. Experimental results have revealed that some steroidal derivatives possess direct cytostatic effect on cancer cells in a hormone receptor-independent manner. After a brief account on the most important biological function and characteristics of the naturally occurring sex hormones in physiological and pathological conditions, structural modifications of estrane and androstane scaffolds are discussed in detail. The review covers literature publications (from 2002 to 2012) relating to the synthesis and antiproliferative activity of semisynthetic sex hormone-derived molecules containing simple or heterocyclic substituents. The compounds reviewed are divided into three main categories according to their sterane framework and the nature of substitution. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Androgen receptor increases CD133 expression and progenitor-like population that associate with cisplatin resistance in endometrial cancer cell line

Endometrial cancer (EMC) is a sex steroid hormone-related female malignancy. Androgen and androgen receptor (androgen/AR) signals have been implicated in EMC progression. Cancer stem/progenitor cells (CSPCs) are suspected to link to chemoresistance in patients with EMC. In this study, we examined the androgen/AR roles in cisplatin resistance and CSPC population. We found AR expression increased naive EMC side population, CSPC population, cell migration, and epithelial-mesenchymal transition. Meanwhile, it decreased cisplatin cytotoxic effect on EMC cells. Collaterally, endogenous AR expressions in EMC cells were upregulated in the cisplatin-resisting state. Moreover, AR expression could further enhance CD133 expression, CSPC-related markers, and drug-resistance gene messenger RNA expression in EMC cells. Finally, the AR-associated gene expression might go through indirect regulation. This is the first report revealing AR function on EMC cells' CSPC and cisplatin resistance.

Cytotoxic effect of novel dehydroepiandrosterone derivatives on different cancer cell lines

The aim of this study was to determine the cytotoxic effect of human cancer cells on three series of novel dehydroepiandrosterone derivatives containing triazole or pyrazole rings at C-17 and an ester moiety at C-3 of the androstane skeleton. The panel cancer cells used in this study were the following: PC-3, MCF-7 and SKLU-1. The results from this study indicated that the steroidal derivatives 4a-4e and 4f-4k showed the highest cytotoxic potency. This difference in this activity could be attributed to the ability of the triazole (three nitrogen atoms) to form stronger hydrogen bonds with the active site of the cell as compared to the pyrazole group having two nitrogen atoms. Compounds 4f-4k having an aromatic ester at C-3 showed an enhanced cytotoxic activity as compared to their aliphatic counterparts 4a-4e. Apparently the electronegative phenyl ring increased the polarity of the molecule, thus increasing the dipole-dipole association of the steroidal molecule with the reactive site of the cell.