Synthesis, antiproliferative, acute toxicity and assessment of antiandrogenic activities of some newly synthesized steroidal lactams

Secosteroid diacylhydrazines as novel effective agents against hormone-dependent breast cancer cells

This research aimed to develop novel selective secosteroids that are highly active against hormone-dependent breast cancer. A simple and convenient approach to N'-acylated 13,17-secoestra-1,3,5(10)-trien-17-oic acid hydrazides was disclosed and these novel types of secosteroids were screened for cytotoxicity against the hormone-dependent human breast cancer cell line MCF7. Most secosteroid N'-benzoyl hydrazides have demonstrated high cytotoxicity against MCF7 cells with IC50 values below 5 μM, which are superior to that of the reference drug cisplatin. Hit compounds 2c, 2e and 2i were characterized by high cytotoxicity (IC50 = 1.6-1.9 μM) and very good selectivity towards MCF7 breast cancer cells. The lead secosteroids 2c, 2e and 2i also exhibit antiestrogenic effects and alter the expression of cell cycle regulating proteins. The effect of selected compounds on PARP (poly(ADP-ribose) polymerase) and Bcl-2 (B-cell CLL/lymphoma 2) indicates their proapoptotic potential. The synthesized secosteroids may be considered as new promising anti-breast cancer agents targeting ERα and apoptosis pathways.

Synthesis and in vitro antimicrobial activity of new steroidal hydrazone derivatives

Background

For many years, various drugs have been used for the treatment of infectious diseases but some bacterial microorganisms have induced resistance to several drugs. In a search of new antimicrobial agents, a series of new steroidal hydrazones were designed and synthesized.

Result

The structures of the compounds were established based on the spectral data. The in vitro antimicrobial activity of some newly synthesized compounds against bacteria and fungi was studied.

Conclusion

New compounds showed better or similar antimicrobial activity. Designing more efficient steroidal hydrazones from ketosteroid based on the current study may successfully lead to the development of antimicrobial agent.

Graphical abstract

Target specific uptake of a newly synthesized radiolabeled 5α-reductase inhibitor “Tc-99m-17-Oxo-17a-Aza-D-Homo-5-Androsten-3β-yl phenoxyacetate (Tc-99m-17a-Aza Steroid)” in rat prostatic neoplastic lesions

Objective:

Considering the 5α-reductase (5AR) inhibitory activity of the oximes and the importance of the ester group in increasing the anti-androgenic property, we reasoned to synthesize a compound having a lactam group in ring D and an ester group at the 3 β position of the androsterone nucleus. The study aims to radiolabel 17-oxo-17a-aza-D-homo-5-androsten-3β-yl phenoxyacetate (17a-aza steroid) with Tc-99m to evaluate its targeted uptake in experimentally induced prostate carcinogenesis in rats.

Materials and Methods:

The prediction of the optimal interaction and binding affinity of Tc-99m-17-oxo-17a-aza-D-homo-5-androsten-3 β-ylphenoxyacetate (Tc-99m-17a-aza steroid) toward 5AR inhibitor was done using Biopredicta Vlife MDS tool. Tc-99m-17a-aza steroid was developed by direct radiolabeling protocol. The radio-pharmacological characteristics (serum stability, plasma protein-binding ability, and lipophilicity) of the complex were evaluated. Further, the bio-distribution studies of the complex were performed in rats with experimentally induced prostate carcinogenesis.

Results:

The in-silico analysis exhibits favorable binding of Tc-99m-17a-aza toward 5AR with D score-130.97. The radiochemical purity of Tc-99m-17a-aza was 96.79%. The radio-complex maintained stability in the rat serum for a period of 6 h (hours). Plasma protein binding and Log Po/w value were observed to be 86.23 ± 7.08% and 0.118 ± 0.045, respectively. A significantly enhanced percent-specific uptake was observed in the prostate of rats with induced prostate carcinogenesis.

Conclusion:

The study concludes that Tc-99m-17a-aza exhibits prostate specificity and can be explored further for its potential as a radionuclide imaging probe.

A Convenient Synthesis of (16S,20S)-3β-Hydroxy-5α-pregnane-20,16-carbolactam and Its N-alkyl Derivatives

A concise synthesis of (16S,20S)-3β-hydroxy-5α-pregnane-20,16-carbolactam from tigogenin via the corresponding lactone is described. The most efficient synthetic route consisted of the lactone ring-opening with aminoalane reagent followed by PDC or Dess-Martin oxidation. The oxo-amide obtained was subjected to cyclization with Et₃SiH/TFA or Et₃SiH/Bi(TfO)₃. Alternately, the lactone was converted first to the oxo-acid, which was then subjected to the microwave-assisted reductive amination. N-Alkyl derivatives were also obtained in a similar way.

Design, synthesis, brine shrimp lethality and cytotoxicity of some novel 17a-aza-D-homo-androster-17-one derivatives

In this work, twenty-eight novel 17a-aza-D-homo-androster-17-one derivatives, which divided into two categories, were synthesized with commercial available starting material (dehydroepiandrosterone) via oximation reaction, Beckmann rearrangement, hydroxyl protection, N-alkylation and deprotection. All compounds were characterized by ¹H NMR, ¹³C NMR and HRMS. The structure of 14 g was also identified by X-ray single crystal diffraction. The bioactivities, brine shrimp toxicity and cytotoxicity, of all derivatives were tested. The results indicated that compounds 11 h, 11i, 11 m, 11 s, 14 b and 14 g exhibited excellent toxicity against brine shrimp with LC₅₀ values ranging from 5.34 to 16.89 μg/mL, and compounds 11 s and 14 g displayed significant cytotoxicity against HT29 cells and A549 cells with IC₅₀ values of 9.70 μM and 8.85 μM, respectively. Structure-activity relationships are discussed based on the results obtained from our research, and some important determinants for further modification of steroids towards the development of novel drug candidates are identified.

Steroidal thiazolidinone derivatives: Design, synthesis and their molecular interaction with human serum albumin

A series of steroidal thiazolidinone derivatives have been synthesized through one-pot multicomponent reaction involving steroidal ketone, thiosemicarbazide/methyl-thiosemicarbazide and DMAD in presence of AlCl₃ as a Lewis acid catalyst. Among all the synthesized steroidal thiazolidinone derivatives, compound 7-9 (ST 7-9) were investigated for their in vitro molecular interaction with human serum albumin. Intrinsic fluorescence spectroscopy, constant wavelength synchronous fluorescence spectroscopy, circular dichroism and UV-visible absorption techniques have been exploited to characterize the binding phenomena in phosphate buffer solution at pH 7.4. The experimental results indicated that ST 7-9 bind to HSA and the intrinsic fluorescence of HSA was quenched through static quenching mechanism. The binding parameters were calculated and the binding constants obtained were 1.44 × 10⁵ M^-1 for ST 7, 0.84 × 10⁵ M^-1 for ST 8 and 1.06 × 10⁵ M^-1 for ST 9. Circular dichroism analysis confirms that the presence of ST 7-9, altered the secondary structure of HSA due to partial unfolding of the polypeptide chain. Furthermore, hemolytic activity assay demonstrated that the synthesized steroidal thiazolidinone derivatives have good compatibility towards human red blood cells. Finally, molecular docking studies revealed that the steroidal thiazolidinones can bind in the hydrophobic cavity of HSA, by hydrophobic and hydrogen bonding interaction. These results provided valuable information about the binding mechanism of ST 7-9 with HSA and play a pivotal role in the development of steroidal heterocycle inspired compounds.

Synthesis and preliminary screening for the biological activity of some steroidal Δ4-unsaturated semicarbazone derivatives

Eleven new steroidal mono- and bis(semicarbazones) 2a-e, 4d and 3a-e have been prepared starting from various 3-oxo-α,β-unsaturated steroids. Mono-semicarbazones 2a-e were further subjected to ethyl chloroacetate in boiling absolute ethanol but, instead of expected intramolecular cyclocondensation reaction products, the new carbazate esters 5a-e were obtained. The structures of all synthesized compounds and identification of each E/Z isomer were deduced by elemental analysis, HRMS, NMR, and IR spectroscopy. Preliminary screening for the cytotoxic activity in vitro of the new compounds has been conducted against three cancer cell lines, K562, Jurkat and HeLa cells. HeLa cells were the most sensitive while K562 cells were the least sensitive to the cytotoxic action of the novel steroid derivatives. Compounds 2e, 3c and 5e were found to have the best but still moderate cytotoxic effects. All tested compounds showed very weak antimicrobial activities. These results demonstrate that the replacement of thioxo group with carbonyl group in steroidal hydrazone derivatives resulted in decrease in their biological activity.

Novel synthesis of steroidal oximes and lactams and their biological evaluation as antiproliferative agents

A novel three-step methodology to obtain 6a-aza-B-homo steroidal lactams has been developed starting from the easily available cholesterol and pregnenolone. In addition, a new procedure for the synthesis of a 6a-aza-B-homo steroidal lactam analog of vespertilin, starting from diosgenin has been established. In both synthetic pathways, the key intermediate is a hydroxyimino derivative obtained in a one- or two-step sequence from the starting materials. These methods avoid the use of hazardous oxidant agents in the process. The new steroidal oximes and lactams were examined for their antiproliferative activities against several tumor cell lines. The 6,23-dihydroxyimino derivative exhibited the highest activity with GI₅₀ values of 11-22µM.

Synthesis, characterization and in vitro cytotoxic activities of new steroidal thiosemicarbazones and thiadiazolines

New steroidal thiosemicarbazones and 1,3,4-thiadiazolines as potential anticancer agents are described.

Synthesis and antiproliferative evaluation of some novel B-nor-D-homosteroids

Using 3β-hydroxy-5-androsten-17-one as a starting material, a series of novel nitrogen-containing B-nor-D-homosteroids were designed and synthesized by the oximation, Beckman rearrangement, ozonation, cyclization and condensation reaction. The structures of all new compounds were determined by analysis of their NMR, MS and IR spectra. The antiproliferative activity of compounds was evaluated against HT-29 (colonic carcinoma), HeLa (human cervical carcinoma) and Bel 7404 (human liver carcinoma) cells.

Synthesis and evaluation of some new aza-B-homocholestane derivatives as anticancer agents

Using analogues of some marine steroidal oximes as precursors, a series of aza-B-homocholestane derivatives possessing different substituted groups at the 3-position of the steroidal nucleus were synthesized. Their biological activity against cancer cell proliferation was determined with multiple cancer cell lines. Aza-B-homocholestane derivatives possessing 3-hydroxyl, 3-hydroximino and 3-thiosemicarbazone groups displayed remarkable cytotoxicity to cancer cells via apoptosis inducing mechanism. Compounds 5, 10, 12, 15 and 18 exhibited better potency to inhibit cancer cell proliferation. In addition, compound 15 was further evaluated with three dimensional (3D) multicellular spheroids assay to determine its potency against spheroid growth. The structure-activity relationship (SAR) generated in the studies is valuable for the design of novel chemotherapeutic agents.

Synthesis and cytotoxic activity of some 4,6-diaza-A,B-dihomo-steroid bilactams

Using cholesterol, stigmasterol and sitosterol as starting materials, some 4,6-diaza-A,B-dihomo-steroid bilactams were synthesized via two different synthetic routes by oxidation, reduction, oximation, Beckman rearrangement, etc. The cytotoxic activity of the synthesized compounds against SGC 7901 (human ventriculi carcinoma), Bel-7404 (human liver carcinoma), HeLa (human cervical carcinoma) and HT-29 (colonic carcinoma) cancer cells were investigated. The results showed that compounds 2 and 7b displayed a good cytotoxic activity to the SGC 7901, Bel 7404 and HeLa tumor cell lines with the IC50 values of 11.6, 16.4, 13.9 and 13.1, 21.8, 13.1 μmol/L, respectively. Their cytotoxic activity is almost same as cisplatin to these cells. The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs.

Steroidal 5α-reductase and 17α-hydroxylase/17,20-lyase (CYP17) inhibitors useful in the treatment of prostatic diseases

The role of steroidal inhibitors of androgen biosynthesis as potential weapons in the treatment of prostatic diseases, such as benign prostatic hyperplasia and prostatic cancer will be reviewed. Two enzymes have been targeted in the development of inhibitors that potentially could be useful in the management of such conditions. 5α-Reductase is primarily of interest in benign prostatic disease, though some role in the chemoprevention of prostatic carcinoma have been considered, whereas the 17α-hydroxylase/17,20-lyase (CYP17) enzyme is of interest in the treatment of malignant disease. An overview of the main achievements obtained during the past years will be presented, however special focus will be made on steroidal molecules that reached clinical trials or have been commercially launched. Relevant examples of such drugs are finasteride, dutasteride, abiraterone acetate and galeterone (TOK-001, formerly known as VN/124-1). This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Synthesis and evaluation of some 17-acetamidoandrostane and N,N-dimethyl-7-deoxycholic amide derivatives as cytotoxic agents: structure/activity studies

Using pregnenolone and 7-deoxycholic acid as starting materials, some 17-acetamidoandrostane and N,N-dimethyl-7-deoxycholic amide derivatives were synthesized. The cytotoxicity of the synthesized compounds was tested in vitro against two tumor cell lines: SGC 7901 (human gastric carcinoma) and Bel 7404 (human liver carcinoma). The result showed that the blockage of the interaction of the amide group with outside groups might cause a decrease of the cytotoxicity, and an O-benzyloximino group at the 3-position of N,N-dimethyl-7-deoxycholic amide could enhance the cytotoxic activity of the compound. The information obtained from the studies provides the structure-activity relationship for these compounds and may be useful for the design of novel chemotherapeutic drugs.

Anticancer steroids: linking natural and semi-synthetic compounds

Steroids, a widespread class of natural organic compounds occurring in animals, plants and fungi, have shown great therapeutic value for a broad array of pathologies. The present overview is focused on the anticancer activity of steroids, which is very representative of a rich structural molecular diversity and ability to interact with various biological targets and pathways. This review encompasses the most relevant discoveries on steroid anticancer drugs and leads through the last decade and comprises 668 references.