Design, synthesis and bioactivity of novel naphthalimide-benzotriazole conjugates against A549 cells via targeting BCL2 G-quadruplex and inducing autophagy.

AIMS: In this study, a series of novel naphthalimide-benzotriazole conjugates (1a-3c) based on 1, 8-naphthalimide as a core skeleton, aiming at G-quadruplexes, were designed and synthesized, and their anti-cancer activity and mechanism were studied. MATERIALS AND METHODS: Using the CCK-8 assay, FRET melting, EMSA, CD, and molecular docking, intracellular assays, western blotting, immunofluorescence, and flow cytometry. KEY FINDINGS: By the CCK-8 assay, it was found that the compound, 2-(3-(piperazin-1-yl)propyl)-6-(1H-benzo [d][1,2,3]triazol-1-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (3a), has better activity against A549 cells. Through extracellular assays, including FRET melting, EMSA, CD, and molecular docking, results showed that 3a selectively interacted with BCL2 G-quadruplex(es). Further studies by intracellular assays, including western blotting, immunofluorescence, flow cytometry, etc., verified that 3a mediated the death of A549 cells by two pathways: inhibition of the expression of the BCL2 gene, causing tumor cell apoptosis, and promotion of genetic instability, causing autophagy. This study suggests that the type of compounds, in particular, 3a, may be a potential molecule to explore for BCL2 G-quadruplex-targeted drugs against lung cancer. SIGNIFICANCE: Our findings demonstrate that compound 3a as a BCL2 G-quadruplex ligand induces DNA damage, autophagy, and apoptosis in A549 cells. This study provides us with a type of lead compound as an anti-tumor drug.

Design, synthesis and anti-cancer activity of pyrrole-imidazole polyamides through target-downregulation of c-kit gene expression.

Pyrrole-imidazole polyamide (PIP) can specifically bind in the B-DNA minor groove that has been used in several biological applications, such as anti-cancer activity, gene expression and translation control, and visualization of complex genomic areas. c-kit is a family member of the Tyrosine Kinase (RTK) type III receptor and plays a vital role in tumor growth, proliferation, differentiation, and cell apoptosis; however, its mutations and overexpression induce tumor dysfunction. Here, we designed and synthesized five matched PIPs that can recognize and bind to the DNA sequence in the oncogene c-kit promoter region, and evaluated their anti-cancer activity. The RTCA assay findings revealed that the PIPs would prevent the proliferation of cancer cells A549 and SGC-7901. EMSA assay showed that the PIPs were actively interacting with the c-kit gene target DNA. RT-PCR and Western blot assays have an effect on expression levels of the c-kit gene in the presence of PIPs. Flow cytometry and wound-healing assays showed that PIPs 4, 5 would cause apoptosis of cancer cells and inhibit the migration of cells, respectively. Overall findings indicate that PIP 5 has a relatively significant intracellular and extracellular impact on the target, contributing to migration and proliferation reduction, and cancer cell apoptosis. In addition, PIP has a certain ability to evolve into c-kit gene-targeting drugs.

Quinoline-3-carboxamide derivatives as potential cholesteryl ester transfer protein inhibitors.

A series of novel quinoline-3-carboxamide derivatives 10-17 and 23-27 were designed and synthesized as cholesteryl ester transfer protein (CETP) inhibitors. All of them exhibited activity against CETP. Particularly, compounds 24 and 26 displayed the best activity against CETP with the same inhibitory rate of 80.1%.

CoMFA, CoMSIA and eigenvalue analysis on dibenzodioxepinone and dibenzodioxocinone derivatives as cholesteryl ester transfer protein inhibitors.

CoMFA, CoMSIA and eigenvalue analysis (EVA) were performed to study the structural features of 61 diverse dibenzodioxepinone and dibenzodioxocinone analogues to probe cholesteryl ester transfer protein (CETP) inhibitory activity. Three methods yielded statistically significant models upon assessment of cross-validation, bootstrapping, and progressive scrambling. This was further validated by an external set of 13 derivatives. Our results demonstrate that three models have a good interpolation as well as extrapolation. The hydrophobic features were confirmed to contribute significantly to inhibitor potencies, while a pre-oriented hydrogen bond provided by the hydroxyl group at the 3-position indicated a good correlation with previous SAR, and a hydrogen bond acceptor may play a crucial role in CETP inhibition. These derived models may help us to gain a deeper understanding of the binding interaction of these lactone-based compounds and aid in the design of new potent compounds against CETP.

Molecular dynamics simulations of HIV-1 protease monomer: Assembly of N-terminus and C-terminus into beta-sheet in water solution.

HIV-1 protease (HIV-PR) consists of two identical subunits that are united together through a four-stranded antiparallel beta-sheet formed of the peptide termini of each monomer. Since the active site exists only in the dimer, a strategy that is attracting more and more attention in inhibitor design and which may overcome the serious drug resistance caused by competitive inhibitors is to block the peptide termini of the monomer, thereby interfering with formation of the active dimer. In the present work, we performed several extensive molecular dynamics (MD) simulations of the HIV-PR monomer in water to illustrate its solvated conformation and dynamics behavior. We found that the peptide termini usually assembled into beta-sheet after several nanoseconds' simulation, and became much less flexible. This beta-sheet is stabilized by intramolecular interactions and is not easily disaggregated under the present MD simulation conditions. This transformation may be an important transition during the relaxing and equilibrating of the HIV-PR monomer in aqueous solution, and the terminal beta-sheet may be one of the major conformations of the solvated HIV-PR monomer termini in water. This work may provide new insights into the dynamics behavior and dimerization mechanism of HIV-PR, and more significantly, offer a more rational receptor model for the design and discovery of novel dimerization inhibitors than crystalline structures.