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Pteridines are an important class of heterocyclic compounds with diverse biological activities. Here, we report a series of pteridin-7(8 H )-one derivatives and their antiproliferative activities toward MKN-45, MGC-803, EC-109, and H1650. Structure-activity relationship studies showed that compound 12 exerted the most potent antiproliferative activity against MKN-45 and MGC-803 with the IC 50 values of 4.32 and 7.01 μM, respectively. Besides, compound 12 induced morphological changes and apoptosis of MKN-45 cells, increased expression of Bax, down-regulated expression of Bcl-2 and caused cleavage of caspase-3/9. Additionally, we first reported the construction of the novel bicyclic 8,9-dihydro-7 H -purine-8-carboxylate scaffold through the competitive 5-endo cyclization reaction with two C-N bonds and a chiral carbon center established. [ABSTRACT FROM AUTHOR]

A series of new [1,2,3]triazolo[4,5- d ]pyrimidine/thiourea hybrids were designed and synthesized through the scaffold replacement/ring cleavage strategy. SARs studies revealed that the N -heteroarene moiety attached to the thiourea is preferred over the phenyl ring for the R 2 substituents, while the hydrophobic aromatic group is beneficial for improving the activity. Among these compounds, compound 5r significantly inhibited cell growth of lung cancer cell lines H1650 and A549 (IC 50 = 1.91, 3.28 μM, respectively), but was less toxic against the normal cell line GES-1 (IC 50 = 27.43 μM). Mechanistic studies showed that compound 5r could remarkably inhibit the colony formation of H1650 cells, induced apoptosis possibly through the intrinsic apoptotic pathways, and arrested the cell cycle at G2/M phase. Our studies suggest that the [1,2,3]triazolo[4,5- d ]pyrimidine/thiourea hybrids are a new class of chemotypes possessing interesting antiproliferative activity against lung cancer cells and could be potentially utilized for designing new antitumor agents. [ABSTRACT FROM AUTHOR]

A series of thiazolo[5,4- d ]pyrimidine derivatives were designed through the atom replacement strategy based on biologically validated scaffolds and then evaluated for their antiproliferative activities on cancer cell lines. The structure-activity relationship studies were conducted, leading to the identification of compound 22 , which exhibited good antiproliferative activity against HGC-27 with an IC 50 value of 1.22 μM and low toxicity against GES-1 cells. Mechanistic studies showed that compound 22 inhibited the colony formation and migration of HGC-27 as well as induced apoptosis. The western blot experiments proved that compound 22 up-regulated expression of Bax, down-regulated expression levels of Bcl-2 and cleaved caspased-3/9. These findings indicate that compound 22 may serve as a template for designing new agents for the treatment of human gastric cancers. The atom replacement strategy could be viable strategy for designing new anticancer drugs and may find its applications in drug design. [ABSTRACT FROM AUTHOR]

A series of thiazolo[5,4-d]pyrimidine derivatives were synthesized and evaluated for their antiproliferative activities on three cancer cell lines. The structure-activity relationship studies were conducted through the variation in the three regions of the thiazolo-pyrimidine core. Substitution with morpholine led to compound 24 , which exerted the most potent antiproliferative activity as well as good selectivity between cancer and normal cells (IC 50 values of 1.03 μM against MGC803 and 38.95 μM against GES-1). In addition, compound 24 inhibited the colony formation and migration of MGC803 as well as induced apoptosis. Western blot experiments indicated the expression changes of apoptosis-related proteins, including up-regulation of Bax and caspase-3/9, as well as down-regulation of Bcl-2. [ABSTRACT FROM AUTHOR]

A series of [1,2,3]triazolo[4,5- d ]pyrimidine derivatives bearing a hydrazone moiety were designed, synthesized and evaluated for their antiproliferative activity against several cancer cell lines of different origins by MTT assay. Most of the synthesized compounds demonstrated moderate to good activity against the cancer cell lines selected. Especially, compound 43 showed the most potent antiproliferative activity as well as good selectivity between cancer and normal cells (IC 50 values of 0.85 μM against MGC-803 and 56.17 μM against GES-1). In addition, compound 43 evidently inhibited the colony formation of MGC-803 cells at 0.8 μM. Further mechanism studies revealed that compound 43 could induce apoptosis of MGC-803 cells probably through the mitochondrial pathway accompanied with decrease of the mitochondrial membrane potential (MMP), activations of caspase-9/3, up-regulation of the expression of Bax, Bak and PUMA, as well as down-regulation of that of Bcl-2 and Mcl-1. [ABSTRACT FROM AUTHOR]

Pteridines are an important class of fused heterocycles found in natural products and drug molecules, and have shown diverse biological activities. A focused library of 5,8-dihydropteridine-6,7-dione derivatives were designed and evaluated for their antiproliferative activity against MGC-803, SGC-7901, A549 and PC-3 cancer cell lines. The SARs studies highlighted the importance of the piperazine substituted 5,8-dihydropteridine-6,7-dione frameworks for the activity and revealed essential structural elements. Among these compounds, compound 5n displayed the most potent and broad-spectrum antiproliferative inhibition against the tested cell lines and was sensitive to MGC-803 cell line, slightly more potent than 5-FU. Preliminary mechanistic studies showed that compound 5n could inhibit the colony formation and migration of MGC-803 cells. Besides, flow cytometry analysis showed that compound 5n concentration-dependently induced apoptosis of MGC-803 cells. Our studies suggest that the piperazine substituted 5,8-dihydropteridine-6,7-dione frameworks may be regarded as new chemotypes for designing effective antitumor agents targeting gastric cancer cells. [ABSTRACT FROM AUTHOR]

Abstract To explore anti-gastric cancer agents with high efficacy and selectivity, we report the design, synthesis and optimization of a novel series of 3-(2,6,9-trisubstituted-9H-purine)-8-chalcone derivatives starting from the compound PCA-15 reported by us previously. Most of the target compounds demonstrated significant antiproliferative effects on MGC803 cancer cell line, and more potent than the positive control (PCA-15 and 5-Fu). Among them, compound 6o was identified to be the most active compound against MGC803 cell line with an IC 50 value of 0.84 μM. Additionally, high selectivity was also observed between cancer and normal cells (23.35 μM against GES-1). Further mechanism studies confirmed that compound 6o could inhibit colony formation and migration, induce the apoptosis of MGC803 cells through both the mitochondrial-mediated intrinsic pathway and death receptor-mediated extrinsic pathway, which were evidenced by the up-regulation of Bax, cleaved-caspase 9/3/8, cleaved PARP and down-regulation of Bcl-2. Our systematic studies implied a new scaffold targeting gastric cancer cells for further development of small-molecule compounds with improved potency and selectivity. Graphical abstract Image 1 Highlights • A novel purine-chalcone scaffold was established by structural optimization, which led to a gradually improved activity. • Compound 6o exerted the potent anti-gastric cancer activity and good selectivity between cancer and normal cells. • Compound 6o could inhibit migration and induce the apoptosis of MGC803 cells. [ABSTRACT FROM AUTHOR]

A new series of 6-chloro-2-(propylthio)-8,9-dihydro-7H-purine-8-caboxamide derivatives were designed, synthesized, and further evaluated for their antiproliferative activities on four human cancer cell lines (A549, MGC803, PC-3 and TE-1). The structure-activity relationships (SARs) studies were conducted through the variation in the two regions, which including position 8 and 9, of purine core. One of the compounds, 8 , containing a terminal piperazine appendage with a carboxamide moiety at position 8 and phenyl group at position 9 of 6-chloro-8,9-dihydro-7H-purine core, showed the most potent antiproliferative activity and good selectivity between cancer and normal cells (IC 50 values of 2.80 μM against A549 and 303.03 μM against GES-1, respectively). In addition, compound 8 could inhibit the colony formation and migration of A549 cells in a concentration-dependent manner, as well as induce the apoptosis possibly through the intrinsic pathway. [ABSTRACT FROM AUTHOR]

A series of hybrid molecules containing [1,2,3]triazolo[4,5-d]pyrimidine and thiosemicarbazide moieties were designed, synthesized and evaluated for their antiproliferative activities against MGC-803, NCI-H1650 and PC-3 human cancer cells. Some of the synthesized compounds showed moderate to good activity against three selected cancer cell lines. Among these compounds, compound 29 displayed the most potent antiproliferative activity as well as good selectivity between cancer cells and normal cells. Further mechanism studies revealed that compound 29 could obviously inhibit the colony formation and migration of MGC-803 as well as induced apoptosis. [ABSTRACT FROM AUTHOR]

A series of 5,6-diaryl-1,2,4-triazines hybrids bearing a 1,2,3-triazole linker were synthesized by molecular hybridization strategy and evaluated for antiproliferative activity against three selected cancer cell lines (MGC-803, EC-109 and PC-3). The first structure-activity relationship (SAR) for these 5,6-diaryl-1,2,4-triazines is explored in this report with evaluation of 15 variants of the structural class. Among these chemical derivatives, 3-(((1-(4-fluorobenzyl)-1H-1,2,3-triazol-4-yl)methyl)thio)-5,6-diphenyl-1,2,4-triazine ( 11E ) showed the more potent inhibitory effect against three cell lines than 5-Fu. Cellular mechanism studies in MGC-803 cells elucidated 11E inhibited colony formation and arrested cell cycle at G2/M phase. Furthermore, compound 11E caused morphological changes, decreased mitochondrial membrane potential, and induced apoptosis through the apoptosis-related proteins in MGC-803 cells. It was the first time, to our knowledge, that 5,6-diaryl-1,2,4-triazines bearing a 1,2,3-triazole linker were used as potential apoptosis inducers. [ABSTRACT FROM AUTHOR]