Cytotoxicity and modes of action of 4′-hydroxy-2′,6′-dimethoxychalcone and other flavonoids toward drug-sensitive and multidrug-resistant cancer cell lines

IntroductionResistance of cancer to chemotherapy is a main cause in treatment failure. Naturally occurring chalcones possess a wide range of biological activities including anti-cancer effects. In this work, we evaluated the antiproliferative activity of three chalcones [4′-hydroxy-2′,6′-dimethoxychalcone (1), cardamomin (2), 2′,4′-dihydroxy-3′,6′-dimethoxychalcone (3)], and four flavanones [(S)-(–)-pinostrobin (4), (S)-(–)-onysilin (5) and alpinetin (6)] toward nine cancer cell lines amongst which were multidrug resistant (MDR) types.MethodsThe resazurin reduction assay was used to detect the antiproliferative activity of the studied samples whilst flow cytometry for the mechanistic studies of the most active molecule (1).ResultsIC₅₀ values in a range of 2.54 μM against CEM/ADR5000 leukemia cells to 58.63 μM toward hepatocarcinoma HepG2 cells were obtained with 1. The lowest IC₅₀ values of 8.59 μM for 2 and 10.67 μM for 3 were found against CCRF-CEM cells leukemia cells, whilst the corresponding values were above 80 μM for 4 and 6. P-glycoprotein-expressing and multidrug-resistant CEM/ADR5000 cells were much more sensitive toward compound 1 than toward doxorubicin and low cross-resistance or even collateral sensitivity was observed in other drug-resistent cell lines to this compound. Normal liver AML12 cells were more resistant to the studied compounds than HepG2 liver cancer cells, indicating tumor specificity at least to some extent. Compound 1 arrested the cell cycle between Go/G1 phase, strongly induced apoptosis via disrupted mitochondrial membrane potential (MMP) and increased production of reactive oxygen species (ROS) in the studied leukemia cell line.ConclusionsChalcone 1 was the best tested cytotoxic molecule and further studies will be performed in order to envisage its possible use in the fight against multifactorial resistant cancer cells.     

Design,synthesis, and evaluation of a water-soluble antofine analogue with high antiproliferative and antitumor activity

New water soluble antofine C-13a analogues were designed, synthesized, and evaluated for antiproliferative activity against cancer cells. Particularly, (?)-(R)-13a-hydroxymethylantofine ((?)-(R)-4b) demonstrated notable growth inhibition against a panel of human cancer cell lines. This growth inhibition was associated with the arrest of the cell cycle in the G0/G1 phases and suppression of mTOR signaling in human lung A549 cancer cells. Compound (?)-(R)-4b also overcame paclitaxel-resistance in human lung cancer cells (A549-Pa) by suppressing P-glycoprotein expression. Furthermore, compound (?)-(R)-4b significantly inhibited the tumor growth of A549 and A549-Pa xenografts in a nude mouse model, which suggests it is a promising novel antitumor agent with sufficient aqueous solubility.     

Antiproliferative and apoptotic effects of compounds from the flower of Mammea siamensis (Miq.) T. Anders. on human cancer cell lines

On the search for anti-cancer compounds from Thai traditional herb medicines, a bioassay-guided fractionation and chemical investigation of the methanol extract of Mammea siamensis flower resulted in the isolation and identification of eight compounds (1–8) including a novel geranylated coumarin, namely mammeanoyl (2), and seven known compounds (1 and 3–8). The structure of new compound 2 was elucidated based on the extensive spectroscopic and chemical methods. Among the isolated compounds, three structurally related coumarins 3, 4, and 5 showed significant antiproliferative activities against human leukemia and stomach cancer cell lines. However, these compounds did not affect the cell viabilities of colon cancer, hepatoma, and normal skin fibroblast cell lines. Further analysis demonstrated that the morphological features of apoptosis including DNA fragmentation and chromatin condensation were observed in human leukemia HL-60 cells treated with compounds 3, 4, and 5. In addition, compound 3 led to caspase-3 activation and cleavage of poly (ADP-ribose) polymerase (PARP), and compound 3-induced DNA fragmentation was inhibited by caspase-specific inhibitors. These results suggest that compound 3, 4, and 5 exert antiproliferative actions through apoptotic cell death in leukemia cells and these compounds may have the potential to be developed into new anti-cancer drug candidates.     

Synthesis and evaluation of novel 7-azaindazolyl-indolyl-maleimide derivatives as antitumor agents and protein kinase C inhibitors

A series of novel 7-azaindazolyl-indolyl-maleimides were synthesized and evaluated for their antiproliferative activity in vitro against various human cancer cell lines and protein kinase C inhibitory activity. Compounds 8a–c, 8e and 14a were the most promising compounds against K562, A549, ECA-109, KB and SMMC-7721 cell lines in vitro. Compounds 9a–j showed moderate PKC inhibition. Further mechanism of action studies revealed that the antiproliferative activity of compound 8b in KB cells might involve the mitochondria-mediated apoptosis pathway.     

Novel 4-aminoquinazoline derivatives induce growth inhibition,cell cycle arrest and apoptosis via PI3Kα inhibition

Phosphatidylinositol 3-kinase (PI3K) signaling pathway has diverse functions, including the regulation of cellular survival, proliferation, cell cycle, migration, angiogenesis and apoptosis. Among class I PI3Ks (PI3Kα, β, γ, δ), the PIK3CA gene encoding PI3K p110α is frequently mutated and overexpressed in a large portion of human cancers. Therefore, the inhibition of PI3Kα has been considered as a promising target for the development of a therapeutic treatment of cancer. In this study, we designed and synthesized a series of 4-aminoquinazoline derivatives and evaluated their antiproliferative activities against six cancer cell lines, including HCT-116, SK-HEP-1, MDA-MB-231, SNU638, A549 and MCF-7. Compound 6b with the most potent antiproliferative activity and without obvious cytotoxicity to human normal cells was selected for further biological evaluation. PI3K kinase assay showed that 6b has selectivity for PI3Kα distinguished from other isoforms. The western blot assay and PI3K kinase assay indicated that 6b effectively inhibited cell proliferation via suppression of PI3Kα kinase activity with an IC₅₀ of 13.6?nM and subsequently blocked PI3K/Akt pathway activation in HCT116 cells. In addition, 6b caused G1 cell cycle arrest owing to the inhibition of PI3K signaling and induced apoptosis via mitochondrial dependent apoptotic pathway. Our findings suggested that 6b has a therapeutic value as an anticancer agent via PI3Kα inhibition.     

Design,synthesis and biological evaluation of new carbazole derivatives as anti-cancer and anti-migratory agents

Based on the efficacy of EHop-016 as an inhibitor of migration and Rac1 activation, a new series of carbazole derivatives has been synthesized. Cytotoxic and anti-migratory effects of these compounds were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines. Preliminary investigations of their anticancer activity demonstrated that several compounds have moderate antiproliferative effects on cancer cell lines with GI₅₀ values in the range of 13–50?µM. Furthermore, compounds 3b and 11b inhibit migration activity of metastatic cell line MDA-MB-231 by 32% and 34%, respectively. Compound 11b was shown to inhibit activation of the Rho GTPase Rac1 by 55% at 250?nM in both MDA-MB-231 and MDA-MB-435 cell lines. Compared with the IC₅₀ of Rac1 inhibition by lead compound EHop-016 of 1.1?µM, compound 11b demonstrates 4X improved in vitro efficacy.     

Synthesis,antioxidant and antiproliferative activities of 1,3,4-thiadiazoles derived from phenolic acids

Two 2-amino-1,3,4-thiadiazoles containing phenolic hydroxyl groups were combined with different carboxylic acid chlorides giving sixteen amide derivatives with good antioxidant and antiproliferative potential. The compound 3′c with an adamantane ring displayed excellent DPPH radical scavenging activity and good cytotoxic activity against human acute promyelocytic leukemia HL-60 cells, while 1,3,4-thiadiazole 3′h with 4-chlorophenyl moiety was found to be the most effective in inhibition of survival of lung carcinoma A549 cells. All examined thiadiazoles except 3a and 3′a exerted higher cytotoxic activities on A549 and HL-60 cancer cells when compared with normal fibroblasts MRC-5, pointing to selectivity in their antiproliferative action. Some of the most active novel compounds 3c, 3′c, 3′g and 3′h induced significant increase in the percentage of HL-60 cells in the subG1 cell cycle phase in comparison with the control cells. The induction of cell death in HL-60 cells by these compounds was at least partially dependent on activation of caspase-3 and caspase-8. The compounds 3c and 3′c exerted strong antiangiogenic activity. Furthermore, compounds 3c, 3′c, 3′g and 3′h showed the ability to down-regulate the MMP2 and VEGFA expression levels in the treated HL-60 cells when compared with the control cell samples.     

Synthetic strategy for increasing solubility of potential FLT3 inhibitor thieno[2,3-d]pyrimidine derivatives through structural modifications at the C2 and C6 positions

Acute myeloid leukemia (AML) is a clonal disorder of hematopoietic progenitor cell. In AML, a mutation in FLT3 is commonly occurs and is associated with poor prognosis. We have previously reported that thieno[2,3-d]pyrimidine derivative compound 1 exhibited better antiproliferative activity against MV4-11 cells which harbor mutant FLT3 than AC220, which is a well-known FLT3 inhibitor, and has good microsomal stability. However, compound 1 had poor solubility. We then carried out further structural modification at the C₂ and the C₆ positions of thieno[2,3-d]pyrimidine scaffold. Compound 13b, which possesses a thiazole moiety at the C₂ position, exhibited better antiproliferative activity than compound 1 and showed increased solubility and moderate microsomal stability. These results indicate that compound 13b could be a promising potential FLT inhibitor for AML chemotherapy.     

Design,synthesis and biological research of novel N-phenylbenzamide-4-methylamine acridine derivatives as potential topoisomerase I/II and apoptosis-inducing agents

A series of novel N-phenylbenzamide-4-methylamine acridine derivatives were designed and synthesized based initially on the structure of amsacrine (m-AMSA). Molecular docking suggested that the representative compound 9a had affinity for binding DNA topoisomerase (Topo) II, which was comparable with that of m-AMSA, and furthermore that 9a could have preferential interactions with Topo I. After synthesis of 9a and analogues 9b-9f, these were all tested in vitro and the synthesized compounds displayed potent antiproliferative activity against three different cancer cell lines (K562, CCRF-CEM and U937). Among them, compounds 9b, 9c and 9d exhibiting the highest activity with IC₅₀ value ranging from 0.82 to 0.91 μM against CCRF-CEM cells. In addition, 9b and 9d also showed high antiproliferative activity against U937 cells, with IC₅₀ values of 0.33 and 0.23 μM, respectively. The pharmacological mechanistic studies of these compounds were evaluated by Topo I/II inhibition, western blot assay and cell apoptosis detection. In summary, 9b effectively inhibited the activity of Topo I/II and induced DNA damage in CCRF-CEM cells and, moreover, significantly induced cell apoptosis in a concentration-dependent manner. These observations provide new information and guidance for the structural optimization of more novel acridine derivatives.     

New derivative of 2-(2,4-dihydroxyphenyl)thieno-1,3-thiazin-4-one (BChTT) elicits antiproliferative effect via p38-mediated cell cycle arrest in cancer cells

2-(2,4-Dihydroxyphenyl)thieno-1,3-thiazin-4-ones are a group of new compounds with potential anticancer activity. This type of derivatives was poorly investigated in the area of synthesis and biological activities. In the present study the antiproliferative action of the most active derivative BChTT was described. The aim of biological evaluation was to investigate the ability of the compound to inhibit cancer cell proliferation and identify mechanism involved in its action on the molecular level. BChTT inhibited the proliferation of lung cancer A549, colon cancer HT-29 and glioma C6 cells in the concentration-dependent manner. It was not toxic to normal cells including skin fibroblasts, hepatocytes and oligodendrocytes in the antiproliferative concentrations. BChTT decreased the DNA synthesis in the treated cancer cells and induced cell cycle arrest in the G0/G1 phase. Moreover, the ability of the compound to activate p38 kinase and decrease cyclin D1 expression was estimated. Participation of p38 kinase in the antiproliferative action of the compound was confirmed by the analysis of BChTT activity in the cells with the p38 silenced gene. The obtained results may suggest the ability of the tested derivative to inhibit cancer cells proliferation by induction of p38-mediated cyclin D1 downregulation.     

Discovery and optimization of 3,4,5-trimethoxyphenyl substituted triazolylthioacetamides as potent tubulin polymerization inhibitors

Based on our previous research, three series of new triazolylthioacetamides possessing 3,4,5-trimethoxyphenyl moiety were synthesized, and evaluated for antiproliferative activities and inhibition of tubulin polymerization. The most promising compounds 8b and 8j demonstrated more significant antiproliferative activities against MCF-7, HeLa, and HT-29 cell lines than our lead compound 6. Moreover, analogues 8f, 8j, and 8o manifested more potent antiproliferative activities against HeLa cell line with IC₅₀ values of 0.04, 0.05 and 0.16?μM, respectively, representing 100-, 82-, and 25-fold improvements of the activity compared to compound 6. Furthermore, the representative compound, 8j, was found to induce significant cell cycle arrest at the G₂/M phase in HeLa cell lines via a concentration-dependent manner. Meanwhile, compound 8b exhibited the most potent tubulin polymerization inhibitory activity with an IC₅₀ value of 5.9?μM, which was almost as active as that of CA-4 (IC₅₀?=?4.2?μM). Additionally, molecular docking analysis suggested that 8b formed stable interactions in the colchicine-binding site of tubulin.     

Synthesis and molecular docking study of new benzofuran and furo[3,2-g]chromone-based cytotoxic agents against breast cancer and p38α MAP kinase inhibitors

This study deals with synthesis of a new set of benzofuran and 5H-furo[3,2-g]chromone linked various heterocyclic functionalities using concise synthetic approaches aiming to gain new antiproliferative candidates against MCF-7 breast cancer cells of p38α MAP kinase inhibiting activity. The biological data proved the significant sensitivity of breast cancer cell lines MCF-7 towards most of the prepared compounds in comparison with doxorubicin. In addition, compounds IIa,b, Va,b, VIa,b, VIIa,b, VIIIa,b, XIc showed significant in vitro p38α MAPK inhibiting potency comparable to the reference standard SB203580. Cell cycle analysis and apoptosis detection data demonstrated that compound VIa induced G2/M phase arrest and apoptosis in MCF-7 cancer cells, in addition to its activation of the caspases-9 and -3. Gold molecular docking studies rationalized the highly acceptable correlation between the calculated docking scores of fitness and the biological data of p38α MAP kinase inhibition. The newly prepared benzofuran and 5H-furo[3,2-g]chromone derivatives might be considered as new promising nuclei in anti-breast cancer chemotherapeutics for further functionalization, optimization and in-depth biological studies.     

Discovery of indoline derivatives that inhibit esophageal squamous cell carcinoma growth by Noxa mediated apoptosis

A series of novel indoline derivatives were synthesized and evaluated for antiproliferative activity against four selected cancer cell lines (Hela, A549, HepG2 and KYSE30). Among them, compound 20 displayed the potent inhibition activity against esophageal cancer cells (Kyse30, Kyse450, Kyse510 and EC109). Cellular mechanism studies in esophageal squamous cell carcinoma (ESCC) cells elucidated compound 20 inhibited cell growths in vitro and in vivo, reduced colony formation, arrested cell cycle at M phase, and induced Noxa-dependent apoptosis in ESCC. Importantly, compound 20 was identified as a novel Noxa mediated apoptosis inducer. These results suggested that compound 20 might be a promising anticancer agent with potential for development of further clinical applications.     

Xanthones and a benzophenone from the roots of Pentadesma butyracea and their antiproliferative activity

A new xanthone, 3,4-dihydro-8,10,12-trihydroxy-2,2-dimethylpyrano[2,3-b]xanthen-11(2H)-one or butyraxanthone E (1), along with the known compounds 30-epi-cambogin (2), 1,7-dihydroxyxanthone (3) and 1,5-dihydroxyxanthone (4) were isolated from the roots of Pentadesma butyracea. Their structures were elucidated by spectroscopic means and comparison with published data. Their antiproliferative activities were evaluated against Drosophila S2 cells and two human cancer cell lines, THP-1 (leukemia) and HCT116 (colon cancer). Compounds 1 and 2 showed moderate antiproliferative activity against Drosophila S2 cells and the HCT116 cell line, respectively. Compound 2 was active against Drosophila S2 cells.     

New indole-based chalconoids as tubulin-targeting antiproliferative agents

Tubulin-targeting compounds have a broad anticancer spectrum and are an important class of chemotherapeutic agents. Due to the importance of 3-bromo-3,5-dimethoxyphenyl scaffold in the anticancer activity of microtubule inhibitors such as crolibulin (EPC2407), we introduced this functionality into the indole-derived chalcones. Thus, we describe here the synthesis and biological evaluation of new indole-based chalconoids as tubulin-targeting antiproliferative agents. The best result was obtained by compound 9b against A549 cell with IC₅₀ of 4.3 µg/mL, being more potent than the reference drug etoposide. Further biological evaluations revealed that compound 9b can inhibit tubulin polymerization and decrease the mitochondrial thiol content, resulting the induction of apoptosis in cancer cells. Docking studies with tubulin indicated that compound 9b could bind to the colchicine binding site.     

Design and synthesis of various quinizarin derivatives as potential anticancer agents in acute T lymphoblastic leukemia

A series of quinizarin derivatives containing quaternary ammonium salts and/or thiourea groups were synthesized and their anticancer activities against leukemia cell lines have been tested. Results showed that most of quinizarin derivatives could inhibit the proliferation of leukemia cells. Among these derivatives, compound 3 showed good inhibition activity against various leukemia cells with IC₅₀ values ranging from 0.90?±?2.55?μM to 10.90?±?3.66?μM. At the same time, compound 3 also inhibited the growth of human embryonic kidney-293 cell (HEK-293). Molt-4 and Jurkat cells, acute T lymphoblastic leukemia (T-ALL) cell lines, were selected to reveal potential anticancer mechanism of compound 3. Compound 3 inhibited the proliferation of Molt-4 and Jurkat cells in a dose- and time-dependent manner and led to a marked G0/G1 phase arrest. Analysis of Annexin V-APC and intracellular reactive oxygen species (ROS) level by flow cytometry showed that compound 3 induced significant apoptosis in Molt-4 and Jurkat cells. Western blotting assay showed that compound 3 activated the caspase-dependent apoptosis pathway and induced the degradation of Bcl-2 and c-myc protein.     

Design,synthesis, and biological evaluation of some novel 4-aminoquinazolines as Pan-PI3K inhibitors

A series of 4-aminoquinazolines derivatives containing hydrophilic group were designed and identified as potent Pan-PI3K inhibitors in this study. The results of antiproliferative assays in vitro showed that this series of compounds had strong inhibition of tumor growth, especially compound 7b for MCF-7 cells but weak inhibition to normal cells. PI3K kinase assay showed that 7b had high activity for three PI3K isoforms with the IC₅₀ values of picomole. The western blot assay indicated that 7b could decrease the phospho-Akt (S473) in a dose-dependent manner. Further experiments showed that 7b could induce apoptosis in MCF-7 cells. Four key hydrogen bonding interactions were found in the docking of 7b with PI3K kinase. All these results suggested that 7b is a potent PI3K inhibitor and could be considered as a potential candidate for the development of anticancer agents.     

Design,synthesis and biological evaluation of novel pteridinone derivatives possessing a hydrazone moiety as potent PLK1 inhibitors

A series of novel pteridinone derivatives possessing a hydrazone moiety were designed, synthesized and evaluated for their biological activity. Most of the synthesized compounds demonstrated moderate to excellent activity against A549, HCT116 and PC-3 cancer cell lines. In particular, compound L₁₉ exhibited the most potent antiproliferative effects on three cell lines with IC₅₀ values of 3.23 μM, 4.36 μM and 8.20 μM, respectively. In kinase assays, the compound L₁₉ also showed potent inhibition activity toward PLK1 with % inhibition values of 75.1. Further mechanism studies revealed that compound L₁₉ significantly inhibited proliferation of HCT-116 cell lines, induced a great decrease in mitochondrial membrane potential resulting in apoptosis of cancer cells, inhibited the migration of tumor cells, and arrested G1 phase of HCT116 cells.