Design and synthesis of novel steroidal imidazoles as dual inhibitors of AR/CYP17 for the treatment of prostate cancer

Steroidal 21-imidazolium salt derivatives: Synthesis and anticancer activity

Nitrogen-containing steroids are known as prostate cancer therapeutics. In this work, a series of pregnane derivatives bearing an imidazolium moiety were synthesized using Δ16-20-ketones as starting material. An improved approach for the construction of the 20-keto-21-heterocycle-substituted fragment involved the rearrangement of 16,17-epoxides with HCl, followed by reaction of the formed α-chloroketone with 1-substituted imidazoles. Binding affinity analysis of the imidazolium steroids and their synthetic intermediates to human CYP17A1 showed only type I (substrate-like) interactions. The strongest affinity was observed for 16α,17α-epoxy-5α-pregnan-20-on-3β-ol (Kd = 0.66 ± 0.05 µM). The steroid derivatives have been evaluated for antitumor activity against a range of prostate cancer cells as well as against various other solid tumor and hematologic cancer cell lines. All 21-imidazolium salts were active against the hormone-dependent prostate cancer line LNCaP. The most pronounced cytotoxicity in solid tumor and hematologic cancer cell lines was observed for intermediate product, 21-chloro-5α-pregn-16-en-20-on-3β-ol. Among the imidazolium salts, the derivatives with a single bond were more cytotoxic than their unsaturated congeners.

The Fundamental Role of Oxime and Oxime Ether Moieties in Improving the Physicochemical and Anticancer Properties of Structurally Diverse Scaffolds

The present review explores the critical role of oxime and oxime ether moieties in enhancing the physicochemical and anticancer properties of structurally diverse molecular frameworks. Specific examples are carefully selected to illustrate the distinct contributions of these functional groups to general strategies for molecular design, modulation of biological activities, computational modeling, and structure-activity relationship studies. An extensive literature search was conducted across three databases, including PubMed, Google Scholar, and Scifinder, enabling us to create one of the most comprehensive overviews of how oximes and oxime ethers impact antitumor activities within a wide range of structural frameworks. This search focused on various combinations of keywords or their synonyms, related to the anticancer activity of oximes and oxime ethers, structure-activity relationships, mechanism of action, as well as molecular dynamics and docking studies. Each article was evaluated based on its scientific merit and the depth of the study, resulting in 268 cited references and more than 336 illustrative chemical structures carefully selected to support this analysis. As many previous reviews focus on one subclass of this extensive family of compounds, this report represents one of the rare and fully comprehensive assessments of the anticancer potential of this group of molecules across diverse molecular scaffolds.

Oxazolinyl derivatives of androst-16-ene as inhibitors of CYP17A1 activity and prostate carcinoma cells proliferation: Effects of substituents in oxazolinyl moiety

Steroid derivatives modified with nitrogen containing heterocycles are known to inhibit activity of steroidogenic enzymes, decrease proliferation of cancer cells and attract attention as promising anticancer agents. Specifically, 2'-(3β-hydroxyandrosta-5,16-dien-17-yl)-4',5'-dihydro-1',3'-oxazole 1a potently inhibited proliferation of prostate carcinoma cells. In this study we synthesized and investigated five new derivatives of 3β-hydroxyandrosta-5,16-diene comprising 4'-methyl or 4'-phenyl substituted oxazolinyl cycle 1 (b-f). Docking of compounds 1 (a-f) to CYP17A1 active site revealed that the presence of substitutents at C4' atom in oxazoline cycle, as well as C4' atom configuration, significantly affect docking poses of compounds in the complexes with enzyme. Testing of compounds 1 (a-f) as CYP17A1 inhibitors revealed that the only compound 1a, comprising unsubstituted oxazolinyl moiety, demonstrated strong inhibitory activity, while other compounds 1 (b-f) were slightly active or non active. Compounds 1 (a-f) efficiently decreased growth and proliferation of prostate carcinoma LNCaP and PC-3 cells at 96 h incubation; the effect of compound 1a was the most powerful. Compound 1a efficiently stimulated apoptosis and caused PC-3 cells death, that was demonstrated by a direct comparison of pro-apoptotic effects of compound 1a and abiraterone.

Synthesis and Biological Evaluation of New Isoxazolyl Steroids as Anti-Prostate Cancer Agents

Steroids with a nitrogen-containing heterocycle in the side chain are known as effective inhibitors of androgen signaling and/or testosterone biosynthesis, thus showing beneficial effects for the treatment of prostate cancer. In this work, a series of 3β-hydroxy-5-ene steroids, containing an isoxazole fragment in their side chain, was synthesized. The key steps included the preparation of Weinreb amide, its conversion to acetylenic ketones, and the 1,2- or 1,4-addition of hydroxylamine, depending on the solvent used. The biological activity of the obtained compounds was studied in a number of tests, including their effects on 17α-hydroxylase and 17,20-lyase activity of human CYP17A1 and the ability of selected compounds to affect the downstream androgen receptor signaling. Three derivatives diminished the transcriptional activity of androgen receptor and displayed reasonable antiproliferative activity. The candidate compound, 24j (17R)-17-((3-(2-hydroxypropan-2-yl)isoxazol-5-yl)methyl)-androst-5-en-3β-ol, suppressed the androgen receptor signaling and decreased its protein level in two prostate cancer cell lines, LNCaP and LAPC-4. Interaction of compounds with CYP17A1 and the androgen receptor was confirmed and described by molecular docking.

Targeting androgen receptor for prostate cancer therapy: From small molecules to PROTACs

Prostate cancer (PCa) remains a serious type of cancer for men worldwide. The majority of new PCa cases are associated with androgen receptor (AR) hyperactivity. Various AR-targeting molecules that suppress its activity have been discovered. In this review, we present the already marketed antiandrogens and a selection of structurally and chemically interesting AR-targeting compounds, from a pharmacochemical perspective. Focus has been placed on the applied design approaches, structural evolution and structure-activity relationships of the most prominent compound classes. Passing from the traditional steroidal AR antagonists to the modern AR-targeting proteolysis targeting chimeras (PROTACs), we intend to provide a comprehensive overview on AR-targeting molecules for PCa treatment.

Discovery of a novel AR/HDAC6 dual inhibitor for prostate cancer treatment

Androgen receptor (AR) and histone deacetylase 6 (HDAC6) are important targets for cancer therapy. Given that both AR antagonists and HDAC6 inhibitors modulate AR signaling, a novel AR/HDAC6 dual inhibitor is investigated for its anticancer effects in castration-resistant prostate cancer (CRPC). Zeta55 inhibits nuclear translocation of AR and suppresses androgen-induced PSA and TMPRSS2 expression. Meanwhile, Zeta55 selectively inhibits HDAC6 activity, leading to AR degradation. Zeta55 reduces the growth of AR-overexpressing VCaP prostate cancer cells both in vitro and in a CRPC xenograft model. These results provide preclinical proof of principle for Zeta55 as a promising therapeutic in prostate cancer treatment.

Antitumor and Radiosensitizing Effects of Zinc Oxide-Caffeic Acid Nanoparticles against Solid Ehrlich Carcinoma in Female Mice

This study aimed to evaluate the anticancer and radio-sensitizing efficacy of Zinc Oxide-Caffeic Acid Nanoparticles (ZnO-CA NPs). ZnO-CA NPs were formulated by the conjugation of Zinc Oxide nanoparticles (ZnO NPs) with caffeic acid (CA) that were characterized by Fourier Transform Infrared Spectra (FT-IR), X-ray Diffractometer (XRD), and Transmission Electron Microscopy (TEM). In vitro anticancer potential of ZnO-CA NPs was evaluated by assessing cell viability in the human breast (MCF-7) and hepatocellular (HepG2) carcinoma cell lines. In vivo anticancer and radio-sensitizing effects of ZnO-CA NPs in solid Ehrlich carcinoma-bearing mice (EC mice) were also assessed. Treatment of EC mice with ZnO-CA NPs resulted in a considerable decline in tumor size and weight, down-regulation of B-cell lymphoma 2 (BCL2) and nuclear factor kappa B (NF-κB) gene expressions, decreased vascular cell adhesion molecule 1 (VCAM-1) level, downregulation of phosphorylated-extracellular-regulated kinase 1 and 2 (p-ERK1/2) protein expression, DNA fragmentation and a recognizable peak at sub-G0/G1 indicating dead cells' population in cancer tissues. Combined treatment of ZnO-CA NPs with γ-irradiation improved these effects. In conclusion: ZnO-CA NPs exhibit in-vitro as well as in-vivo antitumor activity, which is augmented by exposure of mice to γ-irradiation. Further explorations are warranted previous to clinical application of ZnO-CA NPs.

Discovery of novel steroidal-chalcone hybrids with potent and selective activity against triple-negative breast cancer

A series of novel steroidal-chalcone derivates were designed and synthesized based on the molecular hybridization strategy and further evaluated for their growth inhibitory activity against three human cancer cell lines. The MTT results indicated that most compounds were apparently more sensitive to human breast cancer cells MDA-MB-231. Compounds 8 and 18 exerted the best cytotoxic activity against triple-negative MDA-MB-231 cells with the IC₅₀ values of 0.42 μM and 0.52 μM respectively, which were 23-fold increase or more compared with 5-Fu. Further mechanism studies demonstrated that compound 8 could induce cells apoptosis through regulating Bcl-2/Bax proteins and activating caspase-3 signaling pathway. Moreover, compound 8 could upregulate the cellular ROS levels which accelerated the apoptosis of MDA-MB-231 cells. In addition, interestingly, cell cycle assay showed that compound 8 could arrest MDA-MB-231 cells at S phase but not commonly anticipated G2/M phase. These evidences fully confirmed that compound 8 could be a potential candidate that deserves further development as an antitumor agent against triple-negative breast cancer.