Synthesis and Evaluation of Cytotoxic Effects of Amino-ester Derivatives of Natural α,β-Amyrin Mixture

<div><p>Natural α,β-amyrins were isolated from endemic Brazilian Esenbeckia grandiflora Mart., and eight synthetic derivatives were obtained by esterification reactions with bromo acetate, followed by amine treatment. The structures of the all compounds were confirmed by 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and high-resolution mass spectrometry (HRMS) data analysis. The derivatives were screened for cytotoxic activity against human tumor cell-lines PC3 (prostate carcinoma), HCT-116 (colon carcinoma) and HL60 (leukemia). HCT-116 and PC3 cell-lines showed weak tumor growth inhibition (range of 13.9-25.4 and 10.3-28.8%, respectively), but the derivatives presented moderate activity against HL60 (range of 13.6-59.0%). Diethyl, aniline, morpholine and imidazole moieties presented higher activities (range of 45.9-59.0%).</p></div

Docking, Synthesis and Antiproliferative Activity of <i>N</i>-Acylhydrazone Derivatives Designed as Combretastatin A4 Analogues

<div><p>Cancer is the second most common cause of death in the USA. Among the known classes of anticancer agents, the microtubule-targeted antimitotic drugs are considered to be one of the most important. They are usually classified into microtubule-destabilizing (e.g., Vinca alkaloids) and microtubule-stabilizing (e.g., paclitaxel) agents. Combretastatin A4 (CA-4), which is a natural stilbene isolated from <i>Combretum caffrum</i>, is a microtubule-destabilizing agent that binds to the colchicine domain on β-tubulin and exhibits a lower toxicity profile than paclitaxel or the Vinca alkaloids. In this paper, we describe the docking study, synthesis, antiproliferative activity and selectivity index of the <i>N</i>-acylhydrazone derivatives (<b>5a–r</b>) designed as CA-4 analogues. The essential structural requirements for molecular recognition by the colchicine binding site of β-tubulin were recognized, and several compounds with moderate to high antiproliferative potency (IC₅₀ values ≤18 µM and ≥4 nM) were identified. Among these active compounds, LASSBio-1586 (<b>5b</b>) emerged as a simple antitumor drug candidate, which is capable of inhibiting microtubule polymerization and possesses a broad <i>in vitro</i> and <i>in vivo</i> antiproliferative profile, as well as a better selectivity index than the prototype CA-4, indicating improved selective cytotoxicity toward cancer cells.</p></div

Initial conception and molecular design of <i>N</i>-acylhydrazone derivatives 5a–s.

<p>Initial conception and molecular design of <i>N</i>-acylhydrazone derivatives 5a–s.</p

Antiproliferative activity of compounds <b>CA-4</b>, <b>5b</b> and <b>9–12</b> against HL-60, SF295, HCT-8 and MDA-MB435 tumor cells.

<p>Antiproliferative activity of compounds <b>CA-4</b>, <b>5b</b> and <b>9–12</b> against HL-60, SF295, HCT-8 and MDA-MB435 tumor cells.</p

Intermolecular hydrogen bond geometry.

<p>Intermolecular hydrogen bond geometry.</p

ORTEP view of compound 5b with the atom displacement ellipsoids drawn at a 50% probability level.

<p>ORTEP view of compound 5b with the atom displacement ellipsoids drawn at a 50% probability level.</p

Polar interactions between CA-4 (A) or LASSBio-1593 (B) with the colchicine binding site of β-tubulin (PDB code: 1sa0).

<p>Polar interactions between CA-4 (A) or LASSBio-1593 (B) with the colchicine binding site of β-tubulin (PDB code: 1sa0).</p

Design of compounds 9–12 from molecular modification of prototype 5b.

<p>Design of compounds 9–12 from molecular modification of prototype 5b.</p

Hypomethylation at H19DMR in penile squamous cell carcinoma is not related to HPV infection

Penile squamous cell carcinoma (SCC) is a rare and aggressive tumour mainly related to lifestyle behaviour and human papillomavirus (HPV) infection. Environmentally induced loss of imprinting (LOI) at the H19 differentially methylated region (H19DMR) is associated with many cancers in the early events of tumorigenesis and may be involved in the pathogenesis of penile SCC. We sought to evaluate the DNA methylation pattern at H19DMR and its association with HPV infection in men with penile SCC by bisulfite sequencing (bis-seq). We observed an average methylation of 32.2% ± 11.6% at the H19DMR of penile SCC and did not observe an association between the p16INK4a+ (p = 0.59) and high-risk HPV+ (p = 0.338) markers with methylation level. The average methylation did not change according to HPV positive for p16INK4a+ or hrHPV+ (35.4% ± 10%) and negative for both markers (32.4% ± 10.1%) groups. As the region analysed has a binding site for the CTCF protein, the hypomethylation at the surrounding CpG sites might alter its insulator function. In addition, there was a positive correlation between intense polymorphonuclear cell infiltration and hypomethylation at H19DMR (p = 0.035). Here, we report that hypomethylation at H19DMR in penile SCC might contribute to tumour progression and aggressiveness regardless of HPV infection.</p

Conditions and reagents: a) 80% aq. N₂H₄.H₂O, EtOH, reflux, 2 h, 93%.

<p><b>b) ArCHO, EtOH, HCl (cat), r.t., 0.5–4 h, 62–95%</b>.</p