Benzoylurea Derivatives as a Novel Class of Antimitotic Agents: Synthesis, Anticancer Activity, and Structure−Activity Relationships

Synthesis, antimicrobial, anti-cancer and in silico studies of new urea derivatives

The reaction of an alkyl or aryl isocyanates with some primary amines in acetonitrile at room temperature afforded the corresponding alkyl- and aryl-urea derivatives. All the prepared urea compounds have been elucidated by FTIR, NMR, and elemental analysis. The compounds 1 and 3 were confirmed by single-crystal X-ray diffraction. The 4-tolylsulfonyl isocyanate reacted with the aryl amines 1, 2, 3, and 2,4-dichloroaniline to afford the corresponding sulfonylurea derivatives 5-8. Likewise, the reaction of the isocyanates with 2,4-dichloroaniline, 5-methyl isoxazole-3-amine, and 2-aminothiazole derivatives gave the corresponding urea derivatives 9-17. All the prepared compounds 5-17 were tested in vitro as anti-microbial and anti-HepG2 agents. Moreover, analyzing gene expression of TP53-exon4 and TP53-exon7, DNA damage values, and DNA fragmentation percentages have been discussed. The compounds 5 and 8 recorded the highest activity against the tested microbial strains with maximum activity against C. albicans (50 mm) and B. mycoides (40 mm), respectively. The compounds 5 inhibited the growth of E. coli, S. aureus, and C. Albicans at the MIC level of 0.0489 µM, while the compound 8 was able to inhibit the visible growth of E. coli and C. albicans at MIC value of 3.13 µM and S. aureus at 0.3912 µM. In the same line, compound 5 showed the best cytotoxic activity against the HepG2 cell line (IC₅₀ = 4.25 µM) compared to 5 fluorouracil with IC₅₀ = 316.25 µM. Expression analysis of liver cancer related to a gene including TP53-exon4 and TP53-exon7 was used in HepG2 Liver cancer cell lines using RT-qPCR. The expression values of TP53-exon4 and TP53-exon7 genes were decreased. The DNA damage values and DNA fragmentation percentages were increased significantly (P < 0.01) in the treated HepG2 (5) sample compared with the negative control. Docking studies were performed for the synthetic compounds against 2 bacterial proteins (DNA gyrase subunit B, and penicillin binding protein 1a) that are known targets for some antibiotics, and one cell division protein kinase 2 (CDK2) as target for anticancer drugs.

Urea Derivatives in Modern Drug Discovery and Medicinal Chemistry

The urea functionality is inherent to numerous bioactive compounds, including a variety of clinically approved therapies. Urea containing compounds are increasingly used in medicinal chemistry and drug design in order to establish key drug-target interactions and fine-tune crucial drug-like properties. In this perspective, we highlight physicochemical and conformational properties of urea derivatives. We provide outlines of traditional reagents and chemical procedures for the preparation of ureas. Also, we discuss newly developed methodologies mainly aimed at overcoming safety issues associated with traditional synthesis. Finally, we provide a broad overview of urea-based medicinally relevant compounds, ranging from approved drugs to recent medicinal chemistry developments.

Design and synthesis of 4-piperazinyl quinoline derived urea/thioureas for anti-breast cancer activity by a hybrid pharmacophore approach

In an attempt to improve anti-breast cancer activity, a new series of 4-piperazinylquinoline derivatives based on the urea/thiourea scaffold were designed and synthesised by a pharmacophore hybrid approach. We then examined for their antiproliferative effects on three human breast tumor cell lines, MDA-MB231, MDA-MB468 and MCF7, and two non-cancer breast epithelial cell lines, 184B5 and MCF10A. Among those 26 novel compounds examined, 5, 9, 17, 18, 21, 23 and 29 showed significantly improved antiproliferative activity on breast cancer cells. Compound 23 (4-(7-chloro-quinolin-4-yl)-piperazine-1-carbothioic acid (2-morpholin-4-yl-ethyl)-amide) (RL-15) is especially desirable, since its antigrowth/cell-killing activity is 7-11 fold higher on cancer than non-cancer cells. Data from cell biological studies demonstrated that cancer cells compromised plasma membrane integrity in the presence of compound 23. The cancer cell-specific property of compound 23 shown in cell culture stands in vivo test, this compound can be an excellent lead for effective and safe anticancer drug.

A comparative assessment of cytotoxicity of commonly used agricultural insecticides to human and insect cells

The cytotoxic potential of 13 commonly used agricultural insecticides was examined using cell-based systems with three human HepG2, Hek293, HeLa cells and three insect Tn5B1-4, Sf-21, and Drosophila S2 cells. Data showed that (1) an enhancement of some insecticides (e.g. pyrethroids) on cells proliferation; (2) an inhibition of some insecticides on cells viability; (3) various levels of susceptibility of different cells to the same insecticide; and (4) the cell type dependent sensitivity to different insecticides. The degree of cytotoxicity of insecticides on human cells was significantly lower than that on insect cells (P<0.05). Methomyl, even 20μg/ml, showed little cytotoxicity at 24h exposure whereas emamectin benzoate possessed the strongest cytotoxic potential in a dose-dependent fashion. The results revealed comparable cytotoxic property of agricultural insecticides against intact cells.

N-[4-(4,6-Dimethyl-2-pyrimidinyloxy)-3-methylphenyl]-N'-[2-(dimethylamino)] benzoylurea induces cell-cycle arrest and apoptosis in human cancer cells

N-[4-(4,6-Dimethyl-2-pyrimidinyloxy)-3-methylphenyl]-N'-[2-(dimethylamino)]benzoylurea (SUD) is a novel synthesized benzoylurea derivative. We selected several human cancer cell lines to investigate whether SUD can inhibit the growth of cancer cells. We selected the liver cell line L-02 to investigate the effect of SUD on the normal cells. Flow cytometric analysis was used to detect the effect of SUD on cell cycle, Hoechst 33258 staining was used to evaluate the apoptosis induced by SUD, real-time fluorescence quantitative PCR was used to investigate the expression of the cell cycle-relevant and apoptosis-relevant genes, a reactive oxygen species (ROS) assay was used to observe the production of ROS, and western blotting was used to determine the level of cell cycle-relevant and apoptosis-relevant proteins. According to the results of the MTT assay, the growth of human cancer cell lines was significantly inhibited by SUD treatment in a time-dependent and concentration-dependent manner; however, the growth of human normal cells was not significantly inhibited by SUD treatment. The results of flow cytometric analyses showed that SUD induced cell-cycle arrest at the G2-phase in MCF-7 cells and at the G1-phase in BGC-823 cells. The results of Hoechst 33258 staining showed that SUD induced apoptosis in MCF-7 and BGC-823 cells. The results of the ROS assay showed that the production of ROS was increased by SUD in MCF-7 and BGC-823 cells. Our research suggests that the growth-inhibitory effect of SUD on MCF-7 cells was related to G2-phase arrest, which was associated with the upregulated expression of p53 and Chk1 proteins, and downregulation of the cyclin B1 gene, cdc25a, and cyclin-dependent kinase 1 (CDK1) proteins; the growth-inhibitory effect of SUD on BGC-823 cells was related to G1-phase arrest, which was associated with upregulation of the p53 gene and Chk1 protein and downregulation of cdc25a protein and the CDK4 gene. SUD also induced apoptosis in MCF-7 and BGC-823 cell lines through the mitochondrial pathway in a p53-dependent manner.

Comparison of the cytotoxic impact of chlorfluazuron on selected insect and human cell lines

To gain new insight into the mechanism of selective cytotoxicity of benzoylureas as insecticides, the in vitro mode of action of chlorfluazuron was investigated on lepidopteran Tn5B1-4 and Sf-21 cells and human Hek293 and HepG2 cells. Chlorfluazuron inhibited the proliferation of Tn5B1-4 and Sf-21 cells with 50% inhibitory concentration values (IC50) of 4.96 µM and 1.12 µM at 48 h and 2.37 µM and 1.76 µM at 96 h, respectively, versus that of Hek293 and HepG2 cells with IC50 values >20 µM. When transferred to chlorfluazuron-free medium, lepidopteran Tn5B1-4 and Sf-21 cells had a postinhibitory recovery development period within 24 h followed by a suppressed increase in cell viability, but human Hek293 and HepG2 cells showed an accelerated increase over their control level. Chlorfluazuron affected Tn5B1-4 and Sf-21 cells, with ≥1.8-fold decreases in the ratio of cellular N-acetylglucosamine (GlcNAc) level and protein content and ≥1.5-fold increases in the mitotic index and G2 /M-phase arrest. Neither Hek293 nor HepG2 cells contained GlcNAc, and chlorfluazuron had no significant effects on the cell cycle and mitotic index of Hek293 and HepG2 cells. In conclusion, the differences between human and lepidopteran cell lines in the characteristic GlcNAc content, G2 /M arrest in the cycle progress, and mitotic index of cells in response to chlorfluazuron may contribute to the selective toxicity of chlorfluazuron to lepidopteran cells.

Novel acylureidoindolin-2-one derivatives as dual Aurora B/FLT3 inhibitors for the treatment of acute myeloid leukemia

A series of 6-acylureido derivatives containing a 3-(pyrrol-2-ylmethylidene)indolin-2-one scaffold were synthesized as potential dual Aurora B/FLT3 inhibitors by replacing the 6-arylureido moiety in 6-arylureidoindolin-2-one-based multi-kinase inhibitors. (Z)-N-(2-(pyrrolidin-1-yl)ethyl)-5-((6-(3-(2-fluoro-4-methoxybenzoyl)ureido)-2-oxoindolin-3-ylidene)methyl)-2,4-dimethyl-1H-pyrrole-3-carboxamide (54) was identified as a dual Aurora B/FLT3 inhibitor (IC50 = 0.4 nM and 0.5 nM, respectively). Compound 54 also exhibited potent cytotoxicity with single-digit nanomolar IC50 values against the FLT3 mutant-associated human acute myeloid leukemia (AML) cell lines MV4-11 (FLT3-ITD) and MOLM-13 (FLT3-ITD). Compound 54 also specifically induced extrinsic apoptosis by inhibiting the phosphorylation of the Aurora B and FLT3 pathways in MOLM-13 cells. Compound 54 had a moderate pharmacokinetic profile. The mesylate salt of 54 efficiently inhibited tumor growth and reduced the mortality of BALB/c nude mice (subcutaneous xenograft model) that had been implanted with AML MOLM-13 cells. Compound 54 is more potent than sunitinib not only against FLT3-WT AML cells but also active against sunitinib-resistant FLT3-ITD AML cells. This study demonstrates the significance of dual Aurora B/FLT3 inhibitors for the development of potential agents to treat AML.

Concise synthesis and biological evaluation of 2-Aroyl-5-amino benzo[b]thiophene derivatives as a novel class of potent antimitotic agents

The biological importance of microtubules make them an interesting target for the synthesis of antitumor agents. The 2-(3',4',5'-trimethoxybenzoyl)-5-aminobenzo[b]thiophene moiety was identified as a novel scaffold for the preparation of potent inhibitors of microtubule polymerization acting through the colchicine site of tubulin. The position of the methoxy group on the benzo[b]thiophene was important for maximal antiproliferative activity. Structure-activity relationship analysis established that the best activities were obtained with amino and methoxy groups placed at the C-5 and C-7 positions, respectively. Compounds 3c-e showed more potent inhibition of tubulin polymerization than combretastatin A-4 and strong binding to the colchicine site. These compounds also demonstrated substantial antiproliferative activity, with IC50 values ranging from 2.6 to 18 nM in a variety of cancer cell lines. Importantly, compound 3c (50 mg/kg), significantly inhibited the growth of the human osteosarcoma MNNG/HOS xenograft in nude mice.

Synthesis and biological evaluation of novel (thio)urea derivatives as potential antitumor agents

A series of novel (thio)ureas containing the pyrimidinyl group was designed and synthesized. Their in-vitro antitumor activity against different human tumor cells was examined. Some of the compounds showed potential antitumor activity, which provided some hints for further studies on structure modification.

Synthesis, structure-activity relationship and biological evaluation of anticancer activity for novel N-substituted sophoridinic acid derivatives

Sophoridine (1), a natural anticancer drug, has been used in China for decades. A series of novel N-substituted sophoridinic acid derivatives were synthesized and evaluated for their cytotoxicity with 1 as the lead. The structure-activity relationship indicated that introduction of an aliphatic acyl on the nitrogen atom might significantly enhance the anticancer activity. Among the compounds, 6b bearing bromoacetyl side-chain afforded a potential effect against four human tumor cell lines (liver, colon, breast, and lung). The mechanism of action of 6b is to inhibit the activity of DNA topoisomerase I, followed by the S-phase arrest and then cause apoptotic cell death, similar to that of its parent 1. We consider 6b promising for further anticancer investigation.

Synthesis and Evaluation of Haloacetyl, α-Bromoacryloyl and Nitrooxyacetyl Benzo[b]furan and Benzo[b]thiophene Derivatives as Potent Antiproliferative Agents Against Leukemia L1210 and K562 Cells

Identification of novel and selective anticancer agents remains an important and challenging goal in pharmacological research. In search of new compounds with strong antiproliferative activity and simple molecular structure, we have synthesized three different series of compounds in which different substituents were linked to the 3-amino position of the 2-(3', 4', 5'-trimethoxybenzoyl)-benzo[b]furan or benzo[b]thiophene ring system. These substituents, corresponding to acetyl/haloacetyl, α-bromoacryloyl and nitrooxyacetyl moieties had different electrophilic properties. The benzoheterocycle parent structures were selected because of their reported bioactivities. Compounds bearing a methoxy group at the 6-position of the benzo[b]furan skeleton, were identified as potent antiproliferative agents against the human chronic myelogenous K562 and murine L1210 leukemia cell lines. Comparison of positional isomers indicated that moving the methoxy group from the 6- to the 5- or 7-position yielded inactive compounds. The effects of a selected series of compounds on cell cycle progression correlated well with their strong antiproliferative activity and inhibition of tubulin polymerization. The analysis of structure-activity relationships observed in the series of compounds described here may represent a platform for the design of more active molecules.

Synthesis and biological evaluation of 2-(3',4',5'-trimethoxybenzoyl)-3-N,N-dimethylamino benzo[b]furan derivatives as inhibitors of tubulin polymerization

Molecules that target microtubules have an important role in the treatment of cancer. A new class of inhibitors of tubulin polymerization based on the 2-(3,4,5-trimethoxybenzoyl)-2-dimethylamino-benzo[b]furan molecular skeleton was synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization, and cell cycle effects. The most promising compound in this series was 2-(3,4,5-trimethoxybenzoyl)-3-dimethylamino-6-methoxy-benzo[b]furan, which inhibits cancer cell growth at nanomolar concentrations and interacts strongly with tubulin by binding to the colchicine site.