Effect of DNA damage response by quinazolinone analogue HMJ-38 on human umbilical vein endothelial cells: evidence for γH2A.X and DNA-PK-dependent pathway.

The present study aims to explore the mechanism of quinazolinone analogue HMJ-38-induced DNA damage in endothelial cells in vitro. We attempt to evaluate the antiangiogenetic response utilizing human umbilical vein endothelial cells (HUVECs). Herein, the results demonstrated that HMJ-38 incubation triggered DNA damage behavior and showed a longer DNA migration in HUVECs based on the comet assay and the analysis of DNA agarose gel electrophoresis to contact DNA smears. We further gained to determine a marker of DNA double strand breaks, phosphorylated histone H2A.X (Ser139) (γH2A.X), in HMJ-38-treated HUVECs by flow cytometry and Western blotting assay. We consider that HMJ-38 has caused an increase in γH2A.X, and DNA damage seemed to mediate through DNA-dependent serine/threonine protein kinase (DNA-PK) binding to Ku70/Ku80 as well as advanced activated p-Akt (Ser473) and stimulated phosphorylated glycogen synthase kinase-3ß (p-GSK-3ß) conditions in HUVECs. Importantly, the effect of above DNA damage response was prevented by N-acetyl-l-cysteine (a reactive oxygen species scavenger), and NU7026 (a DNA-PK inhibitor) could attenuate DNA-PK catalytic subunit and phosphorylation of H2A.X on Ser139 expression in comparison with HMJ-38 alone treated HUVECs. Therefore, HMJ-38-provoked DNA damage stress in HUVECs probably led to the activation of γH2A.X/DNA-PK/GSK-3ß signaling. In summary, our novel finding provides more information addressing the pharmacological approach of newly synthesized HMJ-38 for further development and therapeutic application in antiangiogenetic effect of cancer chemotherapy.

Molecular modelling, synthesis, cytotoxicity and anti-tumour mechanisms of 2-aryl-6-substituted quinazolinones as dual-targeted anti-cancer agents.

BACKGROUND AND PURPOSE: Our previous study demonstrated that 6-(pyrrolidin-1-yl)-2-(3-methoxyphenyl)quinazolin-4-one (HMJ38) was a potent anti-tubulin agent. Here, HMJ38 was used as a lead compound to develop more potent anti-cancer agents and to examine the anti-cancer mechanisms. EXPERIMENTAL APPROACH: Using computer-aided drug design, 2-aryl-6-substituted quinazolinones (MJ compounds) were designed and synthesized by introducing substituents at C-2 and C-6 positions of HMJ38. The cytotoxicity of MJ compounds towards human cancer cells was examined by Trypan blue exclusion assay. Microtubule distribution was visualized using TubulinTracker(TM) Green reagent. Protein expression of cell cycle regulators and JNK was assessed by Western blot analysis. KEY RESULTS: Compounds MJ65-70 exhibited strong anti-proliferative effects towards melanoma M21, lung squamous carcinoma CH27, lung non-small carcinoma H460, hepatoma Hep3B and oral cancer HSC-3 cells, with one compund MJ66 (6-(pyrrolidin-1-yl)-2-(naphthalen-1-yl)quinazolin-4-one) highly active against M21 cells (IC50 about 0.033 µM). Treatment of CH27 or HSC-3 cells with MJ65-70 resulted in significant mitotic arrest accompanied by increasing multiple asters of microtubules. JNK protein expression was involved in the MJ65-70-induced CH27 and M21 cell death. Consistent with the cell cycle arrest at G2/M phase, marked increases in cyclin B1 and Bcl-2 phosphorylation were also observed, after treatment with MJ65-70. CONCLUSIONS AND IMPLICATION: MJ65-70 are dual-targeted, tubulin- and JNK-binding, anti-cancer agents and induce cancer cell death through up-regulation of JNK and interfering in the dynamics of tubulin. Our work provides a new strategy and mechanism for developing dual-targeted anti-cancer drugs, contributing to clinical anti-cancer drug discovery and application.

P38-associated pathway involvement in apoptosis induced by photodynamic therapy with Lonicera japonica in human lung squamous carcinoma CH27 cells.

Photodynamic therapy (PDT) is an effective therapy for local malignant tumors. Lonicera japonica was found to have the anti-tumor effect. The aim of this study is to explore the mechanisms of apoptosis induced by PDT in lung CH27 carcinoma cells with alcohol extract from Lonicera japonica as photosensitizer. Our study indicated that Lonicera japonica extracts exhibited significant photocytotoxicity in CH27 cells at a concentration range of 50-150 microg/ml, with 0.4-1.2J/cm2 light dose. PDT with Lonicera japonica extracts-induced cell death is a typical apoptosis that was accompanied by DNA condensation, externalization of phosphatidylserine and formation of apoptotic bodies. PDT with Lonicera japonica extracts was shown to be caspase-3-independent apoptosis via activation of AIF in this study. P38-associated pathway may be involved in apoptosis induced by PDT with Lonicera japonica extracts in CH27 cells. We also have demonstrated that PDT with Lonicera japonica extracts-induced CH27 cells apoptosis was probably related to its ability to change the protein expression and distribution of heat shock protein 27.

Kaempferol induces apoptosis in human lung non-small carcinoma cells accompanied by an induction of antioxidant enzymes.

Kaempferol (3, 4',5,7-tetrahydroxyflavone) is one of the most commonly found dietary flavonols. The biological and pharmacological effects of kaempferol may depend upon its behavior as either an antioxidant or a prooxidant. However, the clear biological effects of prooxidant or antioxidant character of kaempferol has not been clarified yet. The overall objective of the present study is to explore the role of prooxidant or antioxidant in kaempferol-induced cell toxicity. In this paper, we have proved that antioxidant pathway may be involved in kaempferol induces H460 cell apoptosis. Kaempferol-induced H460 cell apoptosis is a typical apoptosis that was accompanied by a significant DNA condensation and increasing intracellular ATP levels. Kaempferol-induced apoptosis is related to its ability to change the expression of apoptotic markers, such as caspase-3 (caspase-dependent) and AIF (caspase-independent). The overexpression of antioxidant enzyme Mn SOD protein levels, which was promoted to a new type tumor suppressor gene in several human cancer cells recently, may be an important role in kaempferol-induced H460 cell apoptosis.

Antitumor agents. Part 204: synthesis and biological evaluation of substituted 2-aryl quinazolinones.

A series of 2',3',4',6,7-substituted 2-aryl quinazolinones were synthesized and evaluated for biological activity. Among them, 17 displayed significant growth inhibitory action against a panel of tumor cell lines. Compound 17 was also a potent inhibitor of tubulin polymerization. Compounds 8-10 displayed selective activity against P-gp-expressing epidermoid carcinoma of the asopharynx.

Synthesis of 4-alkoxy-2-phenylquinoline derivatives as potent antiplatelet agents.

In our continuing search for novel antiplatelet agents, 4-alkoxy derivatives of 2-phenylquinoline as well as related compounds were prepared. Through biological screening, a preliminary structure antiplatelet activity relationship was established. Compounds 5-ethyl-4-methoxy-2-phenylquinoline (8), 4-ethoxy-5-ethyl-2-phenylquinoline (9), 4-ethoxycarbonylmethoxy-5-ethyl-2-phenylquinoline (10), 4-ethoxycarbonylbutoxy-5-ethyl-2-phenylquinoline (12) and 5-ethyl-4-(N-ethylcarboxido)methoxy-2-phenylquinoline (17) all demonstrated potent antiplatelet activity. Among them, compound 8 was the most potent with an IC50 value of 0.08 microM and was about 3-fold more active than indomethacin. The mechanism of antiplatelet action of 8 is possibly through its inhibition on cyclooxygenase or thromboxane synthetase.

6-Alkylamino- and 2,3-dihydro-3'-methoxy-2-phenyl-4-quinazolinones and related compounds: their synthesis, cytotoxicity, and inhibition of tubulin polymerization.

As part of our continuing search for potential anticancer candidates among 2-phenyl-4-quinolones and 2-phenyl-4-quinazolinones, two series of 6,7,2',3',4',5'-substituted 2-phenyl-4-quinazolinones and 6,2',3',4',5'-substituted 2,3-dihydro-2-phenyl-4-quinazolinones were synthesized and evaluated for cytotoxicity and as inhibitors of tubulin polymerization. In general, a good correlation was found between the two activities. Five of the 6-substituted heterocyclic 2-phenyl-4-quinozolinones (37-51) showed significant cytotoxicity against a panel of human tumor cell lines with EC(50) values in the low micromolar to nanomolar concentration ranges. Compound 38 was the most potent of these compounds, as well as the most potent inhibitor of tubulin polymerization in this series. The activity of 38 was in the same range as those of the antimitotic natural products, colchicine, podophyllotoxin, and combretastatin A-4. Substituted 2-phenyl-4-quinazolinones and 2, 3-dihydro-2-phenyl-4-quinazolinones also displayed highly selective cytotoxicity against the ovarian cancer 1A9 and P-gp resistant KB-VIN cell lines.

Synthesis and antiplatelet activities of N-arylmethyl-3,4-dimethylpyrano[2,3-c]pyrazol-6-one derivatives.

A series of new 1- and 2-arylmethyl-3,4-dimethylpyrano[2,3-c]pyrazol-6-one derivatives were synthesized and examined for their antiplatelet activities. Some of these compounds showed significant inhibitory activities. Among them, 1-phenylmethyl-3,4-dimethylpyrano[2,3-c]pyrazol-6(1H)-one (4a), 2-(2'-methoxyphenyl)methyl-3,4-dimethylpyrano[2,3-c]pyrazol-6(2H)- one (3e) and 2-(3'-methoxyphenyl)methyl-3,4-dimethylpyrano[2,3-c]pyrazol-6-(2H) - one (3f) were the most effective. These inhibitors acted in a concentration-dependent manner. The antiplatelet effect of compound 3f is due to the inhibition of thromboxane A2 formation and the blockade of thromboxane A2/prostaglandin endoperoxide receptor in washed rabbit platelets.