Synthesis of novel 1,2-bis-quinolinyl-1,4-naphthoquinones : ERK2 inhibition, cytotoxicity and molecular docking studies

Two novel series of N-2,3-bis(6-substituted-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)naphthalene-1,4-diones 3a-d and substituted N-(methyl/ethyl)bisquinolinone triethyl-ammonium salts 4e,f were successfully synthesized. The synthesized compounds were targeted as new candidates to extracellular signal-regulated kinases 1/2 (ERK1/2) with considerable antineoplastic activity. The synthesis involved the reactions of 2 equivalents of 4-hydroxy-2(1H)-quinolinones la-f and one equivalent of 1,4-naphthoquinone (2) in a mixture of ethanol/dimethylformamide (1:1) as a solvent and 0.5 mL Et3N. In the reaction of 6-methyl-4-hydroxyquinolone 1b with 2, a side product 4b of the second series was obtained. In general, the presence of free NH-quinolone gave a single compound of the first series, whereas reaction of N-methyl/ethyl-quinolones 1e, f with 2 enhanced the formation of compounds of the second series. The structures of the new compounds were proved by different spectroscopic techniques such as IR, NMR (2D-NMR) and mass spectra, elemental analysis, and X-ray crystallography. To further elucidate the mechanism of action of these newly synthesized compounds, compounds 3a, 3b, 4e and 4f were selected to investigate for their MAP Kinases pathway inhibition together with molecular docking using ATP-binding site of ERK2. The results revealed that compounds 3a, 3b and 4f inhibited ETS-1 phosphorylation by ERK2 in a dose dependent manner. Also, compound 4f showed highest potency for ERK2 inhibition with ATPcompetitive inhibition mechanism which was confirmed by the formation of three hydrogen bond in the molecular docking studies. The synthesized compounds were then tested for their in vitro anticancer activity against the NCI-60 panel of tumor cell lines. Interestingly, the selected compounds displayed from modest to strong cytotoxic activities. Compound 3b demonstrated broad spectrum anti-tumor activity against the nine tumor subpanels tested, while compound 3d proved to be lethal to most of the cancer cell lines as shown by their promising GI(50) and TGI values in NCI in vitro five dose testing. These results revealed that the synthesized compounds can potentially serve as leads for the development of novel chemotherapeutic agents and structure improvement will be necessary for some derivatives for enhancing their cellular activities and pharmacokinetic profile.Peer reviewe

Synthesis and Structure Determination of Substituted Thiazole Derivatives as EGFR/BRAFV600E^{V600E} Dual Inhibitors Endowed with Antiproliferative Activity

2,3,4-trisubstituted thiazoles 3a–i, having a methyl group in position four, were synthesized by the reaction of 1,4-disubstituted thiosemicarbazides with chloroacetone in ethyl acetate/Et$_3$N at room temperature or in ethanol under reflux. The structures of new compounds were determined using NMR spectroscopy, mass spectrometry, and elemental analyses. Moreover, the structure of compound 3a was unambiguously confirmed with X-ray analysis. The cell viability assay of 3a–i at 50 µM was greater than 87%, and none of the tested substances were cytotoxic. Compounds 3a–i demonstrated good antiproliferative activity, with GI$_{50}$ values ranging from 37 to 86 nM against the four tested human cancer cell lines, compared to the reference erlotinib, which had a GI$_{50}$ value of 33 nM. The most potent derivatives were found to be compounds 3a, 3c, 3d, and 3f, with GI50 values ranging from 37 nM to 54 nM. The EGFR-TK and BRAF$^{V600E}$ inhibitory assays’ results matched the antiproliferative assay’s results, with the most potent derivatives, as antiproliferative agents, also being the most potent EGFR and BRAF$^{V600E}$ inhibitors. The docking computations were employed to investigate the docking modes and scores of compounds 3a, 3c, 3d, and 3f toward BRAF$^{V600E}$ and EGFR. Docking computations demonstrated the good affinity of compound 3f against BRAF$^{V600E}$ and EGFR, with values of −8.7 and −8.5 kcal/mol, respectively

Synthesis and Structure Determination of Substituted Thiazole Derivatives as EGFR/BRAFV600E Dual Inhibitors Endowed with Antiproliferative Activity

2,3,4-trisubstituted thiazoles 3a–i, having a methyl group in position four, were synthesized by the reaction of 1,4-disubstituted thiosemicarbazides with chloroacetone in ethyl acetate/Et3N at room temperature or in ethanol under reflux. The structures of new compounds were determined using NMR spectroscopy, mass spectrometry, and elemental analyses. Moreover, the structure of compound 3a was unambiguously confirmed with X-ray analysis. The cell viability assay of 3a–i at 50 µM was greater than 87%, and none of the tested substances were cytotoxic. Compounds 3a–i demonstrated good antiproliferative activity, with GI50 values ranging from 37 to 86 nM against the four tested human cancer cell lines, compared to the reference erlotinib, which had a GI50 value of 33 nM. The most potent derivatives were found to be compounds 3a, 3c, 3d, and 3f, with GI50 values ranging from 37 nM to 54 nM. The EGFR-TK and BRAFV600E inhibitory assays’ results matched the antiproliferative assay’s results, with the most potent derivatives, as antiproliferative agents, also being the most potent EGFR and BRAFV600E inhibitors. The docking computations were employed to investigate the docking modes and scores of compounds 3a, 3c, 3d, and 3f toward BRAFV600E and EGFR. Docking computations demonstrated the good affinity of compound 3f against BRAFV600E and EGFR, with values of −8.7 and −8.5 kcal/mol, respectively