Design, Synthesis, Characterization, and Cytotoxicity of New Pyrazolylmethylene-2-thioxoimidazolidin-4-one Derivatives towards Androgen-Sensitive LNCaP Prostate Cancer Cells

Abstract

A new class of pyrazolylmethylene-2-thioxoimidazolidin-4-one derivatives 3a-p were rationally designed and synthesized with the aim of exploring their potential as treatments for prostate cancer. The synthesized compounds 3a-p were biologically analyzed for their anticancer effects against AR⁺LNCaP, AR^-PC-3, and Wi38 cell lines. The observed IC₅₀ values against AR⁺LNCaP ranged between 10.27 ± 0.14 and 109.72 ± 2.06 µM after 24 h of incubation. Compounds 3i-k, 3m, and 3o-p recorded IC₅₀ values of 05.22 ± 0.12 to 11.75 ± 0.07 µM after 48 h incubation in the presence of 1 nM DHT, with higher selectivity towards AR⁺LNCaP. Moreover, compounds 3i and 3k significantly induced Caspase 3 accumulation, reduced DNA content at the various stages of the cell cycle, and ultimately caused AR⁺LNCaP cell growth arrest, as confirmed by cell apoptosis assays. These findings suggest that these analogues of androgen receptor blockers have promising potential for further investigation as effective treatments for prostate cancer.

Keywords: LNCaP; PC3; androgen receptors blockers; imidazole; prostate cancer; pyrazole.

Figure 1

Some examples of androgen receptor blockers.

Figure 2

Design of the target hybrid compounds 3a–p.

Scheme 1

Synthesis of derivatives of pyrazolylmethylene-2-thioxoimidazolidin-4-one 3a–p.

Figure 3

Carbon–fluorine splitting in ¹³C-NMR (APT) spectrum of compound 3k.

Figure 3

Carbon–fluorine splitting in ¹³C-NMR (APT) spectrum of compound 3k.

Figure 4

Effect of compounds 3i–k, 3m, and 3o–p and reference drug Enzalutamide treatment on the accumulation of Caspase 3 in AR⁺LNCaP cells compared to control (untreated AR+LNCaP) measured by Invitrogen Elisa kit for detection of active human caspase 3. Data are presented as mean ± SE of at least three independent measurments. Statistical significance was determined compared to untreteated AR+LNCaP cells using one-way ANOVA test.

Figure 5

Evaluation of DNA contents of AR⁺LNCaP cells at the different stages of the cell cycle after treatment with the test compounds 3i and 3k.

Figure 6

Effect of the test compounds 3i and 3k on AR⁺LNCaP cell apoptosis.