Design and synthesis of thiazole derivatives as potent FabH inhibitors with antibacterial activity.

Components of fatty acid biosynthetic pathway have been identified as attractive targets for the development of new antibacterial agents. Compounds of series A (4a-4 g) and series B (5a-5 g) were synthesized by the formation of an amine bond between aromatic acid and 4-phenylthiazol-2-amine or 4-(4-bromophenyl)thiazol-2-amine. These thiazole derivatives have evaluated as potent FabH inhibitors. Nineteen compounds (4b-4h, 4 k, 4 l, 5a-5h, 5k, 5l) are reported for the first time. Most of the synthesized compounds exhibited antibacterial activity in the MTT assay. The MIC value of these compounds ranged from 1.56 µg/mL to 100 µg/mL. Moreover, the tested compounds also showed FabH inhibition ability with IC50 value ranging from 5.8 µM to 48.1 µM. The IC50 values are near the MIC values. Compound 5f has exhibited the best antibacterial and Escherichia coli FabH inhibitory activity. Docking simulation and the QSAR study was conducted for learning about binding mode and the relationship between structure and activity.

Discovery of 4,6-substituted-(diaphenylamino)quinazolines as potent c-Src inhibitors.

A series of 4,6-substituted-(diaphenylamino)quinazolines as c-Src inhibitors have been prepared and their biological activity has also been evaluated. All the compounds displayed potential antiproliferation activities, with IC50 values ranging from 3.42 µM to 118.81 µM in five human tumor cell lines. Particularly, compound 15 exhibited higher cytotoxicity against the tested five tumor cell lines compared to the other small molecules. Generally, most of these compounds showed selectivity between the A549 cells and the other four cells, according to their corresponding IC50 values. The results obtained from the in vitro enzyme assay indicated compound 15 has remarkable inhibitory activity against c-Src kinase with an IC50 value of 27.3 nM, which is comparable to the control compounds. Furthermore, molecular docking and QSAR study by means of DS 3.5 (Discovery Studio 3.5, Accelrys, Co. Ltd) explored the binding modes and the structure and activity relationship (SAR) of these derivatives.

Design, synthesis, biological evaluation, and molecular modeling study of 4-alkoxyquinazoline derivatives as potential VEGFR2 kinase inhibitors.

A series of novel 4-alkoxyquinazoline derivatives were prepared and synthesized and their biological activities were evaluated as potential inhibitors of vascular endothelial growth factor receptor 2 (VEGFR2). Of these compounds, compound 3j demonstrated the most potent inhibitory activities against VEGFR2 tyrosine kinase and cell proliferation, the IC50 values of this compound reaching up to 2.72 nM and 0.35 µM, respectively, compared with Tivozanib (3.40 nM and 0.38 µM). The obtained results, along with a 3D-QSAR study and molecular docking that was used for investigating the probable binding mode, could provide an important basis for further optimization of compound 3j as a potential tyrosine kinase inhibitor.

Optimization of substituted 6-salicyl-4-anilinoquinazoline derivatives as dual EGFR/HER2 tyrosine kinase inhibitors.

4-Anilinoquinazolines as an important class of protein kinase inhibitor are widely investigated for epidermal growth factor receptor (EGFR) tyrosine kinase or epidermal growth factor receptor 2 (HER2) inhibition. A series of novel 6-salicyl-4-anilinoquinazoline derivatives 9-27 were prepared and evaluated for their EGFR/HER2 tyrosine kinase inhibitory activity as well as their antiproliferative properties on three variant cancer cell lines (A431, MCF-7, and A549). The bioassay results showed most of the designed compounds exhibited moderate to potent in vitro inhibitory activity in the enzymatic and cellular assays, of which compound 21 revealed the most potent dual EGFR/HER2 inhibitory activity, with IC50 values of 0.12 µM and 0.096 µM, respectively, comparable to the control compounds Erlotinib and Lapatinib. Furthermore, the kinase selectivity profile of 21 was accessed and demonstrated its good selectivity over the majority of the close kinase targets. Docking simulation was performed to position compound 21 into the EGFR/HER2 active site to determine the probable binding pose. These new findings along with molecular docking observations could provide an important basis for further development of compound 21 as a potent EGFR/HER2 dual kinase inhibitor.

A functional scaffold in marine alkaloid: an anticancer moiety for human.

Marine organisms have been developed as a new source of naturally occurring alkaloids. The bioactive scaffolds of marine alkaloids govern the cross-kingdom actions, possessing "unexpectedly" cytotoxic-related antitumor activities against human cancer cell lines. And the actions of marine alkaloids toward mammalian cells have been well substantiated by the recognition of their analogues as antitumor and enzyme modulatory agents. Different moieties of alkaloids target different cellular pathways. Structure-activity studies and docking analysis of marine alkaloids analogs attached importance to certain privileged moieties, and illustrated the mechanism of alkaloids' functionalization in mammals. The fascinating observations prompted us to review five kinds of alkaloid-like moieties including thiazole, pyrroloquinon, oxazole, pyridine and indole, and illuminate suggestively their various roles in common cellular processes of human beings. Meanwhile, an hypothesis was made correlatively to explain the different mechanisms of their anticancer activities in human cell lines.

Novel 1,3,4-oxadiazole thioether derivatives targeting thymidylate synthase as dual anticancer/antimicrobial agents.

A series of novel 1,3,4-oxadiazole thioether derivatives (compounds 9-44) were designed and synthesized as potential inhibitors of thymidylate synthase (TS) and as anticancer agents. The in vitro anticancer activities of these compounds were evaluated against three cancer cell lines by the MTT method. Among all the designed compounds, compound 18 bearing a nitro substituent exhibited more potent in vitro anticancer activities with IC50 values of 0.7±0.2, 30.0±1.2, 18.3±1.4 µM, respectively, which was superior to the positive control. In the further study, it was identified as the most potent inhibitor against two kinds of TS protein (for human TS and Escherichia coli TS, IC50 values: 0.62 and 0.47 µM, respectively) in the TS inhibition assay in vitro and the most potent antibacterial agents with MIC (minimum inhibitory concentrations) of 1.56-3.13 µg/mL against the tested four bacterial strains. Molecular docking and 3D-QSAR study supported that compound 18 can be selected as dual antitumor/antibacterial candidate in the future study.

Novel Schiff-base-derived FabH inhibitors with dioxygenated rings as antibiotic agents.

Fatty acid biosynthesis plays a vital role in bacterial survival and several key enzymes involved in this biosynthetic pathway have been identified as attractive targets for the development of new antibacterial agents. Of these promising targets, ß-ketoacyl-acyl carrier protein (ACP) synthase III (FabH) is the most attractive target that could trigger the initiation of fatty acid biosynthesis and is highly conserved among Gram-positive and -negative bacteria. Designing small molecules with FabH inhibitory activity displays great significance for developing antibiotic agents, which should be highly selective, nontoxic and broad-spectrum. In this manuscript, a series of novel Schiff base compounds were designed and synthesized, and their biological activities were evaluated as potential inhibitors. Among these 21 new compounds, (E)-N-((3,4-dihydro-2H-benzo[b][1,4]dioxepin-7-yl)methylene)hexadecan-1-amine (10) showed the most potent antibacterial activity with a MIC value of 3.89-7.81 µM(-1) against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with an IC(50) value of 1.6 µM. Docking simulation was performed to position compound 10 into the E. coli FabH active site to determine the probable binding conformation.

Discovery of 6-substituted 4-anilinoquinazolines with dioxygenated rings as novel EGFR tyrosine kinase inhibitors.

It had been reported that some dioxygenated rings fusing with the quinazoline scaffold could lead to new EGFR inhibitors. Based on this, several kinds of oxygenated alkane quinazoline derivatives were synthetized and evaluated as EGFR inhibitors. Their antiproliferative activities were tested against four cancer cell lines: A431, MCF-7, A549, and B16-F10. Most derivatives could counteract EGF-induced EGFR phosphorylation, and their potency was comparable to the reference compound Erlotinib. The size of the fused dioxygenated ring was crucial for the biological activity and the heptatomic ring derivative 19 showed potent in vitro inhibitory activity in the enzymatic assay as well as in the cellular assay.

Hypomethylated CpG around the transcription start site enables TERT expression and HPV16 E6 regulates TERT methylation in cervical cancer cells.

OBJECTIVE: The human papillomavirus (HPV) oncoprotein, E6, activates telomerase reverse transcriptase (TERT) expression and causes cellular immortalization. It remains unclear whether E6 affects TERT transcription by altering DNA methylation profiles. In this study, we explored the methylation status of the TERT promoter in cervical cancer cell lines and its variations after E6 was silenced by RNAi. METHODS: Three kinds of cervical cell lines (HPV16 positive: CaSki and SiHa; HPV18 positive: HeLa), were taken to analyze the methylation status of the TERT promoter by methylation-specific polymerase chain reaction (MSP) and bisulfite sequencing (BS). Stealth RNAi was transiently transfected to these cell lines to silence the expression of HPV16/18 E6, and the subsequent changes of TERT mRNA levels and TERT promoter DNA methylation were examined. RESULTS: Hypomethylation of the DNA around the TERT transcription start site (-156 to +162 bp) was functionally related to its transcription. After transfection with Stealth RNAi, the levels of HPV16/18 E6 and TERT mRNA were greatly decreased. The methylated CpG around the transcription start sites in CaSki and SiHa cells were statistically increased (respectively P=0.016, P=0.000). However, there was no significant difference in HeLa cells (P=0.128). CONCLUSION: Hypomethylated CpG around the transcription start site enables the expression of TERT in cervical cancer cells. Our results show for the first time that HPV16 E6 can promote TERT transcription through demethylating the DNA sequence around the TERT transcription start site in cervical squamous cancer cells.

[Clinical application of telomerase RNA component gene amplification assay in cervical lesions.].

OBJECTIVE: To investigate the significance of genomic amplification of the telomerase RNA component (TERC) gene to serve as a genetic biomarker in the screening of cervical lesions. METHODS: A total of 715 cases were recruited, with liquid-based cytology diagnosis as normal (n = 347), atypical squamous cells of undetermined significance (ASCUS, n = 180), atypical squamous cells cannot exclude a high-grade lesion (ASC-H, n = 13), low-grade squamous intraepithelial lesions (LSIL, n = 115), high-grade squamous intraepithelial lesions (HSIL, n = 59) and atypical glandular cells (AGC, n = 1). The remaining cervical cells in the cytological preserving fluid were analyzed using a two-color fluorescence in situ hybridization (FISH) probe targeted to chromosome 3q26 containing TERC gene. The TERC gene findings were compared to the cytological and histological detected results, as well as high-risk human papillomavirus (HPV) detected results. RESULTS: Genomic amplification of TERC gene was found in 5.8% of normal specimens, 22.2% of ASCUS, 30.8% of ASC-H, 27.8% of LSIL, 86.4% of HSIL and 1/1 of AGC. The positive rate was significantly lower in normal, ASCUS, ASC-H and LSIL compared with HSIL (all P < 0.01). Significantly more cells with genomic amplification of TERC gene were found in cervical intraepithelial lesion (CIN) II-III than CINI (77.8% vs. 9.3%), as well as invasive cervical cancer (96.7% vs. 9.3%), both P < 0.01. The rate of TERC gene amplification was higher in HPV positive patients (33.5%) than in HPV negative patients (5.2%, P < 0.01). The sensitivity of TERC gene amplification was significantly higher than that of cytological screening (81.88% vs. 36.96%, P < 0.01) in the differentiation of CINII or higher and CINI or lower diseases, its specificity was higher than high-risk HPV test (93.32% vs. 33.93%, P < 0.01) and positive prediction value (81.29%) was similar with cytological method (86.44%, P > 0.05); but its negative prediction value (93.56%) was lower than HPV test (97.06%, P < 0.05). CONCLUSIONS: The positive rates of TERC gene amplification increased as cervical diseases worsened. TERC gene amplification is related to HPV infection. The gain of chromosome 3q26 in cytological specimens is an effective molecular genetic biomarker in screening of CINII or higher and invasive cervical cancer.

[Evaluation of genomic amplification of the human telomerase RNA component gene in the screening of cervical lesions].

OBJECTIVE: To investigate the genomic amplification of the human telomerase RNA component (hTERC) gene in cervical cytology and evaluate its role in screening of cervical lesions. METHODS: A total of 301 cases were recruited, with liquid-based cytology diagnoses as normal (n = 203), atypical squamous cells (ASC, n = 66), low-grade squamous intraepithelial lesions (LSIL, n = 18), and high-grade squamous intraepithelial lesions (HSIL, n = 14). Following cytological examination, the slides were analyzed using a two-color fluorescence in situ hybridization (FISH) probe targeted to chromosome 3q26 containing hTERC. The hTERC findings were compared to the cytologic and histologic results, as well as high-risk human papilloma viruses (HPV) results. RESULTS: Genomic amplification of hTERC was found in 3.0% (6/203) of normal specimens, 21.2% (14/66) of ASC, 44.4% (8/18) of LSIL and 92.9% (13/14) of HSIL, with a significant difference in each pair wise (all P < 0.05). Significantly more cells with 3q26 gain were found in cervical intraepithelial lesion (CIN)II than in CINI (75.0% vs. 20.0%), as well as in CINIII (86.7% vs. 20.0%) and squamous cervical cancer (SCC) than in CINI (100.0% vs. 20.0%)(all P < 0.01). The sensitivity of hTERC amplification was significantly higher than cytological screening (82.6% vs. 17.4%, P < 0.01), and its specificity was higher than high-risk HPV test (67.8% - 73.5% vs. 25.6% - 27.7%, P < 0.01) in the diagnosis of HSIL (CINII - III). The abnormal hTERC signal type mostly was 2:3 in CINI (84.9%); whereas in CINII - III, 2:3, 2:4 and 4:4 accounted for 44.6%, 24.8% and 17.8%, respectively. CONCLUSION: Testing the gain of chromosome 3q26 in cytological specimens using specific probe for hTERC is powerful in screening of HSIL, and the amplification patterns of 2:4 and 4:4 may serve as potential prognosis markers.