The design, synthesis, and anti-tumor mechanism study of N-phosphoryl amino acid modified resveratrol analogues

Identification of 3-(9H-carbazol-9-yl)-2-(1,3-dioxoisoindolin-2-yl)propanoic acids as promising DNMT1 inhibitors

DNA methyltransferase 1 (DNMT1) is the primary enzyme responsible for maintaining DNA methylation patterns during cellular division, crucial for cancer development by suppressing tumor suppressor genes. In this study, we retained the phthalimide structure of N-phthaloyl-l-tryptophan (RG108) and substituted its indole ring with nitrogen-containing aromatic rings of varying sizes. We synthesized 3-(9H-carbazol-9-yl)-2-(1,3-dioxoisoindolin-2-yl)propanoic acids and confirmed them as DNMT1 inhibitors through protein affinity testing, radiometric method using tritium labeled SAM, and MTT assay. Preliminary structure-activity relationship analysis revealed that introducing substituents on the carbazole ring could enhance inhibitory activity, with S-configuration isomers showing greater activity than R-configuration ones. Notably, S-3-(3,6-di-tert-butyl-9H-carbazol-9-yl)-2-(1,3-dioxoisoindolin-2-yl)propanoic acid (7r-S) and S-3-(1,3,6-trichloro-9H-carbazol-9-yl)-2-(1,3-dioxoisoindolin-2-yl)propanoic acid (7t-S) exhibited significant DNMT1 enzyme inhibition activity, with IC50 values of 8.147 μM and 0.777 μM, respectively (compared to RG108 with an IC50 above 250 μM). Moreover, they demonstrated potential anti-proliferative activity on various tumor cell lines including A2780, HeLa, K562, and SiHa. Transcriptome analysis and KEGG pathway enrichment of K562 cells treated with 7r-S and 7t-S identified differentially expressed genes (DEGs) related to apoptosis and cell cycle pathways. Flow cytometry assays further indicated that 7r-S and 7t-S induce apoptosis in K562 cells and arrest them in the G0/G1 phase in a concentration-dependent manner. Molecular docking revealed that 7t-S may bind to the methyl donor S-adenosyl-l-methionine (SAM) site in DNMT1 with an orientation opposite to RG108, suggesting potential for deeper penetration into the DNMT1 pocket and laying the groundwork for further modifications.

Covalent Allosteric Inhibitors of Akt Generated Using a Click Fragment Approach

Akt is a protein kinase that has been implicated in the progression of cancerous tumours. A number of covalent allosteric Akt inhibitors are known, and based on these scaffolds, a small library of novel potential covalent allosteric imidazopyridine-based inhibitors was designed. The envisaged compounds were synthesised, with click chemistry enabling a modular approach to a number of the target compounds. The binding modes, potencies and antiproliferative activities of these synthesised compounds were explored, thereby furthering the structure activity relationship knowledge of this class of Akt inhibitors. Three novel covalent inhibitors were identified, exhibiting moderate activity against Akt1 and various cancer cell lines, potentially paving the way for future covalent allosteric inhibitors with improved properties.

Design, Synthesis, and Antitumor Activity of Novel Quinazoline Derivatives

In an attempt to explore a new class of epidermal growth factor receptor (EGFR) inhibitors, novel 4-stilbenylamino quinazoline derivatives were synthesized through a Dimorth rearrangement reaction and characterized via IR, ¹H-NMR, ¹³C-NMR, and HRMS. Methoxyl, methyl, halogen, and trifluoromethyl groups on stilbeneamino were detected. These synthesized compounds were evaluated for antitumor activity in vitro against eight human tumor cell lines with an MTS assay. Most synthesized compounds exhibited more potent activity (IC₅₀ = ~2.0 μM) than gefitinib (IC₅₀ > 10.0 μM) against the A431, A549, and BGC-823 cell lines. Docking methodology of compound 6c and 6i binding into the ATP site of EGFR was carried out. The results showed that fluorine and trifluoromethyl played an important role in efficient cell activity.

Biomimetic Total Synthesis of (±)-Homodimericin A

A biomimetic total synthesis of racemic homodimericin A was achieved in seven steps, including two cascade reactions. Aqueous buffer solutions are found to help both the oxidative dimerization cascade and the intramolecular Diels-Alder cascade. This synthetic sequence validates key steps in the biogenetic proposal of homodimericin A.

C-2 (E)-4-(Styryl)aniline substituted diphenylpyrimidine derivatives (Sty-DPPYs) as specific kinase inhibitors targeting clinical resistance related EGFRT790M mutant

With the aim to overcome the drug resistance induced by the EGFR T790M mutation (EGFR^T790M), herein, a family of diphenylpyrimidine derivatives (Sty-DPPYs) bearing a C-2 (E)-4-(styryl)aniline functionality were designed and synthesized as potential EGFR^T790M inhibitors. Among them, the compound 10e displayed strong potency against the EGFR^T790M enzyme, with the IC₅₀ of 11.0nM. Compound 10e also showed a higher SI value (SI=49.0) than rociletinib (SI=21.4), indicating its less side effect. In addition, compound 10e could effectively inhibit the proliferation of H1975 cells harboring the EGFR^T790M mutation, within the concentration of 2.91μM. Significantly, compound 10e has low toxicity against the normal HBE cell (IC₅₀=22.48μM). This work provided new insights into the discovery of potent and selective inhibitor against EGFR^T790M over wild-type (EGFR^WT).

A facile, stereoselective, one-pot synthesis of resveratrol derivatives

Background

Compounds based on trans-1,2-diphenylethene are the subject of intense interest both for their optical properties and as potential leads for drug discovery, as a consequence of their anticancer, anti-inflammatory and antioxidant properties. Perhaps the best known of these is trans-3,5,4′-trihydroxystilbene (resveratrol), that has been identified as a promising lead in the search for anti-ageing therapeutics.

Results

We report here a new, convenient, one-pot stereo-selective synthesis of resveratrol and other trans-stilbene derivatives. A wide range of known and novel “Resveralogues” were synthesised by using this simple protocol, including examples with electron donating and electron withdrawing substituents, in uniformly high yield. The structures of all compounds were confirmed by standard methods including ¹H and ¹³C NMR, IR and High Resolution Mass spectroscopy.

Conclusions

We have established a simple and convenient protocol for resveralogue synthesis. It is readily scalable, and sufficiently robust and simple for ready use in automated synthesis or for library development of resveralogues. This supersedes previously reported synthetic methods that required inert conditions, extensive purification and/or costly reagents.

Graphical abstract

Novel synthetic acridine derivatives as potent DNA-binding and apoptosis-inducing antitumor agents

Acridine derivatives have been explored as DNA-binding anticancer agents. Some derivatives show undesired pharmacokinetic properties and new derivatives need to be explored. In this work, a series of novel acridine analogues were synthesized by modifying previously unexplored linkers between the acridine and benzene groups and their antiproliferative activity and the DNA-binding ability were evaluated. Among these derivatives, compound 5c demonstrated DNA-binding capability and topoisomerase I inhibitory activity. In K562 cell lines, 5c induced apoptosis through mitochondria-dependent intrinsic pathways. These data suggested that compound 5c and other acridine derivatives with modified linkers between the acridine and benzene groups might be potent DNA-binding agents.

Exploration of acridine scaffold as a potentially interesting scaffold for discovering novel multi-target VEGFR-2 and Src kinase inhibitors

VEGFR-2 and Src kinases both play important roles in cancers. In certain cancers, Src works synergistically with VEGFR-2 to promote its activation. Development of multi-target drugs against VEGFR-2 and Src is of therapeutic advantage against these cancers. By using molecular docking and SVM virtual screening methods and based on subsequent synthesis and bioassay studies, we identified 9-aminoacridine derivatives with an acridine scaffold as potentially interesting novel dual VEGFR-2 and Src inhibitors. The acridine scaffold has been historically used for deriving topoisomerase inhibitors, but has not been found in existing VEGFR-2 inhibitors and Src inhibitors. A series of 21 acridine derivatives were synthesized and evaluated for their antiproliferative activities against K562, HepG-2, and MCF-7 cells. Some of these compounds showed better activities against K562 cells in vitro than imatinib. The structure-activity relationships (SAR) of these compounds were analyzed. One of the compounds (7r) showed low μM activity against K562 and HepG-2 cancer cell-lines, and inhibited VEGFR-2 and Src at inhibition rates of 44% and 8% at 50μM, respectively, without inhibition of topoisomerase. Moreover, 10μM compound 7r could reduce the levels of activated ERK1/2 in a time dependant manner, a downstream effector of both VEGFR-2 and Src. Our study suggested that acridine scaffold is a potentially interesting scaffold for developing novel multi-target kinase inhibitors such as VEGFR-2 and Src dual inhibitors.

A COMPARISON OF THE STEREOISOMERIC PENTA-COORDINATED PHOSPHORUS INTERMEDIATES FORMED FROM 19 DIMETHOXYL N-PHOSPHORYL AMINO ACIDS BY DFT CALCULATIONS

N-phosphoryl amino acids (PAAs) are important species in the origin of life that self-catalyze and self-assemble into polypeptides and polynucleotides under mild conditions. Both experimental and theoretical studies have shown that a penta-coordinated phosphorus intermolecular mixed carboxylic-phosphoric anhydride (IMCPA) is formed as the common intermediate in these reactions. In this work, the mechanism for the formation of stereoisomeric IMCPAs from PAAs is investigated using density functional theory (DFT) calculations at the B3LYP/6-311+G(d,p) theoretical level. The molecular structures of the cis- and the trans-IMCPAs, as well as the transition states of the two stereochemical reaction pathways, were characterized in detail. The results showed that the hydroxyl groups of PAAs were situated in favorable positions for attacking the phosphorus atom from two sides of the phosphoryl group, resulting in the formation of the cis-IMCPA and the trans-IMCPA, respectively. The trans-isomers were predicted to be more likely to undergo a further reaction involving an ester exchange on the phosphorus than the cis-isomers. By comparing the relative energies of the IMCPAs and the activation energies, the trans-IMCPAs were computed to be more stable than the cis-IMCPAs, but the energy barriers for the formation of the trans- and the cis-isomers were similar. This work is expected to shed light on the stereochemical effect involved in the chemical evolution of biomolecules.

Novel synthetic 2-amino-10-(3,5-dimethoxy)benzyl-9(10H)-acridinone derivatives as potent DNA-binding antiproliferative agents

A series of novel 9(10H)-acridinone derivatives with terminal amino substituents at C2 position on the acridinone ring were synthesized and studied for their antiproliferative activity and underlying mechanisms. These compounds demonstrated promising cytotoxicity to leukemia cells CCRF-CEM, displaying IC(50) values in the low micromolar range. Structure-activity relationships (SAR) indicated that the compound 6d bearing a pyrrolidine substituent and 8a with a methyl ammonium side chain displayed higher cytotoxicity to CCRF-CEM cells and also solid tumor cells A549, HepG2, and MCF7. Furthermore, the compounds 6d and 8a had strong binding activity to calf thymus DNA (ct DNA), as detected by UV absorption and fluorescence quenching assays, but limited inhibitory activity to human topoisomerase 1 (topo 1). Taken together, this study discovered a series of new synthetic 9(10H)-acridinone derivatives with potent DNA binding and anticancer activity.

Design, synthesis, and biological evaluation of resveratrol analogues as aromatase and quinone reductase 2 inhibitors for chemoprevention of cancer

A series of new resveratrol analogues were designed and synthesized and their inhibitory activities against aromatase were evaluated. The crystal structure of human aromatase (PDB 3eqm) was used to rationalize the mechanism of action of the aromatase inhibitor 32 (IC50 0.59 microM) through docking, molecular mechanics energy minimization, and computer graphics molecular modeling, and the information was utilized to design several very potent inhibitors, including compounds 82 (IC50 70 nM) and 84 (IC50 36 nM). The aromatase inhibitory activities of these compounds are much more potent than that for the lead compound resveratrol, which has an IC50 of 80 microM. In addition to aromatase inhibitory activity, compounds 32 and 44 also displayed potent QR2 inhibitory activity (IC50 1.7 microM and 0.27 microM, respectively) and the high-resolution X-ray structures of QR2 in complex with these two compounds provide insight into their mechanism of QR2 inhibition. The aromatase and quinone reductase inhibitors resulting from these studies have potential value in the treatment and prevention of cancer.

New synthetic flavone derivatives induce apoptosis of hepatocarcinoma cells

Natural flavonoids have broad biological activity, including anticancer. In this study, a series of novel flavone derivatives were synthesized with the substitutions of chlorine, isopropyl, methoxy, and nitro groups on the benzene ring of flavone skeleton to develop effective anticancer agents. Antiproliferative assays showed that the synthesized chemicals possess notable activity against hepatocarcinoma cells (HepG-2); in particular, the compound 6f with chlorine and dimethoxy modifications at the two benzene rings showed an IC(50) at 1.1 microM to HepG-2. The 6f also displayed marked anticancer activity towards a panel of cancer cells, including nasopharyngeal carcinoma cells (CNE-2 and CNE-1), breast adenocarcinoma cell (MCF-7), and epithelial carcinoma cells (Hela). Exposing HepG-2 cells to compound 6f at 10 microM induced chromatin condensation, nuclear disassembly, and DNA fragmentation. In 6f-treated HepG-2 cells, the sub-G(0) population was remarkably increased; and in these cells, both caspase-8 and caspase-9 activity was significantly increased, which in turn activated caspase-3. In addition, proapoptotic Bax was upregulated by compound 6f while the antiapoptotic Bcl-2 was downregulated. Taken together, our data suggest that the new flavonoid derivative 6f triggers apoptosis through both death-receptor and mitochondria-dependent intrinsic pathways, being a potent therapeutic agent against hepatocarcinoma.

In vitro and in vivo studies on stilbene analogs as potential treatment agents for colon cancer

Based on the potential of resveratrol as a colon cancer chemopreventive agent, a set of 26 stilbenes were synthesized and tested against the colon cancer cell lines HT-29 and Caco-2. (Z)-4-(3,5-Dimethoxystyryl)aniline (4), (Z)-methyl-4-(3,5-dimethoxystyryl)benzoate (6), and (Z)-1,3-dimethoxy-5-(4-methoxystyryl)benzene (10) showed strong inhibitory activity in vitro. In vivo studies using HT-29 xenografts in immunodeficient mice were conducted with 4, 6 and 10, together with their corresponding trans isomers (3, 5, and 9, respectively), at the dose of 10 mg/kg body weight. Tumor volume was significantly lowered in 3-, 4-, and 9-treated groups. The cis- and trans-amino analogs (4 and 3, respectively) had similar effect on tumor growth, a 40% decrease compared to the control. Analysis of the serum revealed that 4 isomerized to 3, which may explain their similar effects in SCID mice. Stilbenes 5, 6, 9, and 10 retained their configurations in the serum. Stilbenes 6 and 10 lacked tumor-suppressive effect in SCID mice; the serum levels of these analogs were low (18.8 and 15.5 ng/mL, respectively). Stilbene 9, while weakly active in vitro demonstrated good activity in vivo, was found at higher levels in the serum (69.9 ng/mL) compared to 10. The anti-tumorigenic activity of these stilbene analogs may be partly linked to their effects on proteins involved in cell proliferation, as observed by lowered expression of proliferating cell nuclear antigen and upregulation of the cyclin-dependent kinase inhibitor, p27, in the tumor tissues. Overall, identification of the anti-tumorigenic potential of these compounds provides opportunities for their use against colorectal cancer.

Resveratrol and resveratrol analogues--structure-activity relationship

Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a compound found in wine and is held responsible for a number of beneficial effects of red wine. Besides the prevention of heart disease and significant anti-inflammatory effects, resveratrol might inhibit tumor cell growth and even play a role in the aging process. We here describe the structure-activity relationship of resveratrol and analogues of resveratrol regarding the free radical scavenging and antitumor effects of this exciting natural compound. In addition, we have synthesized a number of analogues of resveratrol with the aim to further improve the beneficial effects of resveratrol. Our studies were based on the analysis of structural properties, which were responsible for the most important effects of this compound. Striking in vivo effects can be observed with hexahydroxystilbene (M8), the most effective synthetic analogue of resveratrol. We could show that M8 inhibits tumor as well as metastasis growth of human melanoma in two different animal models, alone and in combination with dacarbacine.