Antitumor Effects of the Novel Quinazolinone Holu-12: Induction of Mitotic Arrest and Apoptosis in Human Oral Squamous Cell Carcinoma CAL27 Cells

BACKGROUND/AIM

Quinazolinone is a privileged chemical structure employed for targeting various types of cancer. This study aimed to demonstrate the antitumor activity of synthesized 6,7-disubstituted-2-(3-fluorophenyl) quinazolines (HoLu-11 to HoLu-14).

MATERIALS AND METHODS

The cytotoxicity was assessed by the sulforhodamine B (SRB) assay. The cell cycle was examined by flow cytometry. The expression levels of cell cycle- and apoptosis-related proteins were estimated by western blotting. A xenograft animal model was used to explore the antitumor effects of HoLu-12.

RESULTS

Among four synthetic quinazolinone derivatives, HoLu-12 significantly reduced the viability of oral squamous cell carcinoma (OSCC) cells. HoLu-12 induced G₂/M arrest and increased the expression of cyclin B, histone H3 (Ser10) phosphorylation, and cleaved PARP, indicating that HoLu-12 could induce mitotic arrest and then apoptosis. Moreover, the combination of HoLu-12 and 5-fluorouracil (5-FU) displayed synergistic toxic effect on OSCC cells. HoLu-12 significantly inhibited tumor growth in vivo.

CONCLUSION

HoLu-12 induces mitotic arrest and leads to apoptosis of OSCC cells. Furthermore, HoLu-12 alone or in combination with 5-FU is a potential therapeutic agent for OSCC.

Antitumor activity, multitarget mechanisms, and molecular docking studies of quinazoline derivatives based on a benzenesulfonamide scaffold: Cell cycle analysis

The in vitro cytotoxicity of some substituted quinazolinones, 1-15, was evaluated using NCI (10 µM) in a full NCI 59-cell line panel assay. Relative to the reference drug, imatinib (PCE = 20/59), compounds 3, 4, 7, 9, and 10 exhibited remarkable antitumor activity against the tested cell lines, with positive cytotoxic effects (PCE) of 29/59, 18/59, 17/59, 44/59, and 24/59 respectively. Enzymatic inhibitory assay conducted on 3, 4, 9, and 10 as the most potent antitumor agents against EGFR, HER2 and CDK9 kinases, and COX-2 enzyme. Compound 3 possessed good COX-2 inhibitory activity (IC50 = 0.775 μM) compared to the reference drug, celecoxib (IC50 = 0.153 μM). Compounds 4 and 9 were closely potent to the reference compounds against EGFR and (HER2) tyrosine kinases, with IC50 values of 90.17 (and 131.39 for HER2) for 4 and 145.35 (and 129.07 for HER2) nM for 9; the reference drugs in this case, namely, gefitinib and erlotinib, exhibited IC50 values of 55.58 (90) and 110 (79.28) nM against the EGFR and (HER2) tyrosine kinases, respectively. Compound 4 was approximately similar potent against CDK9 kinase (IC50 = 67.04 nM) like the reference compound, dinaciclib (IC50 = 53.12 nM). Compound 9 induced cytotoxicity in the MCF-7 cell line (GI % at 10.0 μM = 47%) through pre-G1 apoptosis, thereby inhibiting cell growth at the G2/M phase. Molecular docking models of 3 and 4 with COX-2, EGFR, and CDK9 were conducted to determine their binding mode within the putative binding pockets.

Discovery of novel quinazolinone derivatives as potential anti-HBV and anti-HCC agents

As a continuation of earlier works, a series of novel quinazolinone derivatives (5a-s) were synthesized and evaluated for their in vitro anti-HBV and anti-hepatocellular carcinoma cell (HCC) activities. Among them, compounds 5j and 5k exhibited most potent inhibitory effect on HBV DNA replication in both drug sensitive and resistant (lamivudine and entecavir) HBV strains. Interestingly, besides the anti-HBV effect, compound 5k could significantly inhibit the proliferation of HepG2, HUH7 and SK- cells, with IC₅₀ values of 5.44, 6.42 and 6.75 μM, respectively, indicating its potential anti-HCC activity. Notably, the in vitro anti-HCC activity of 5k were more potent than that of positive control 5-fluorouracil and sorafenib. Further studies revealed that compound 5k could induce HepG2 cells apoptosis by dose-dependently upregulating Bad and Bax expression and decreasing Bcl-2 and Bcl-xl protein level. Considering the potent anti-HBV and anti-HCC effect, compound 5k might be a promising lead to develop novel therapeutic agents towards HBV infection and HBV-induced HCC.

Binding of quinazolinones to c-KIT G-quadruplex; an interplay between hydrogen bonding and π-π stacking

Stabilization of G-quadruplex structures in the c-KIT promoter with the aid of ligands has become an area of great interest in potential cancer therapeutics. Understanding the binding process between ligands and G-quadruplex is essential for a discovery of selective ligands with high binding affinity to G-quadruplex. In the present work, binding mechanisms of 4-quinazolinones to c-KIT G-quadruplex were investigated theoretically by means of molecular dynamics (MD) simulations. To explore the binding affinity of ligands, binding free energy calculations were performed using the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method. We demonstrate that the key interactions in G-quadruplex-ligand complexes are π-π stacking and hydrogen bond interactions. However, neither of these two interactions alone determines the stability of the G-quadruplex-ligand complexes; rather, it is the result of an intricate interplay between the two. To further examine the nature of the binding, a free energy decomposition analysis at residue level was carried out. The results clearly demonstrate the crucial roles of two hot spot residues (DG4 and DG8) for the binding of ligands to c-KIT G-quadruplex, and highlight the importance of the planar aromatic moiety of ligands in G-quadruplex stabilization via π-π stacking interactions. Our study can assist in the design of new derivatives of 4-quinazolinone with high binding affinity for c-KIT G-quadruplex.

Assessment of quinazolinone derivatives as novel non-nucleoside hepatitis B virus inhibitors

Hepatitis B virus (HBV) infection is a worldwide public health issue. Search for novel non-nucleoside anti-HBV agents is of great importance. In the present study, a series of quinazolinones derivatives (4a-t and 5a-f) were synthesized and evaluated as novel anti-HBV agents. Among them, compounds 5e and 5f could significantly inhibit HBV DNA replication with IC₅₀ values of 1.54 μM and 0.71 μM, respectively. Interestingly, the selective index values of 5f was higher than that of lead compound K284-1405, suggesting 5f possessed relatively safety profile than K284-1405. Notably, 5e and 5f exhibited remarkably anti-HBV activities against lamivudine and entecavir resistant HBV strain with IC₅₀ values of 1.90 and 0.84 μM, confirming their effectiveness against resistant HBV strain. In addition, molecular docking studies indicated that compounds 5e and 5f could well fit into the dimer-dimer interface of HBV core protein dominated by hydrophobic interactions. Notably, their binding modes were different from the lead compound K284-1405, which may be attributed to the additional substituent groups in the quinazolinone scaffold. Taken together, 5e and 5f possessed novel chemical structure and potent anti-HBV activity against both drug sensitive and resistant HBV strains, thus warranting further research as potential non-nucleoside anti-HBV candidates.

Molecular docking, molecular modeling, vibrational and biological studies of some new heterocyclic α-aminophosphonates

A new diphenyl (aryl) (Ǹ-quinazolin-4-yl-hydrazino) methylphosphonates 3a-3d was synthesized via anhydrous zinc chloride catalyzed Kabachnic-Fields reaction. The structure of the synthesized compounds was confirmed by elemental analysis, FT-IR, ¹H NMR, ¹³C NMR, ³¹P NMR and MS spectral data. The synthesized compounds showed significant antimicrobial and also remarkable cytotoxicity anticancer activities against breast carcinoma cell line (MCF7). The quantum chemical calculations were performed using density functional theory (DFT) to study the effect of the changes of molecular and electronic structures on the biological activity of the investigated compounds. Also, NBO and theoretical FT-IR were calculated. The experimental results were validated by molecular docking simulation of compound 3b in the active pocket of the enzyme. The important binding interactions with the key residues in the active site were revealed. A good correlation was found between the quantum chemical parameters and experimental data.