Ling Hui

Synthesis and biological evaluation of conjugates of deoxypodophyllotoxin and 5-FU as inducer of caspase-3 and -7.

In order to generate compounds with superior antitumor activity and reduced toxicity, a series of conjugates of deoxypodophyllotoxin and 5-FU were synthesized by coupling 4-demethyl-4-dexoypodophyllotoxin with N-(5-fluorouracil-N(1)-ly acetic)- amino acids (or 5-fluorouracil-N(1)-ly acetic acid). The cytotoxic activity of these compounds against four human cancer cell lines (HL-60, A-549, HeLa and SiHa) were evaluated, and results indicated that these compounds were more potent in terms of cytotoxicity than either parent compound DPT or anticancer drug VP-16 and 5-FU. In addition, we found that 14d induced cell cycle arrest in the G2/M phase accompanied by apoptosis in A-549 cells, and 14d activated caspase-3 and -7. These results suggested that caspase-mediated pathways are involved in 14d induced apoptosis.

Synthesis and biological evaluation of derivatives of 4-deoxypodophyllotoxin as antitumor agents.

In an attempt to generate compounds with superior bioactivity and reduced toxicity, a series of derivatives of deoxypodophyllotoxin were synthesized by reacting 4-demethyl-4-deoxypodophyllotoxin with substituted piperazines or their amino acid amides. The cytotoxic activity of these compounds against three human cancer cell lines was evaluated. We found that p-nitrophenylpiperazine substitution (Compound 8b) led to an increase in the potency of the compound. Compound 8b exhibited the most potent cytotoxicity against A-549, HeLa and SiHa cells (IC(50) values were 0.102, 0.180 and 0.0195 μM, respectively). In addition, flow cytometric analysis showed that 8b induced cell cycle arrest in the G1 phase accompanied by apoptosis in A-549 cells.

Carbamates of 4'-demethyl-4-deoxypodophyllotoxin: synthesis, cytotoxicity and cell cycle effects.

In an attempt to generate compounds with superior bioactivity and reduced toxicity, 12 carbamates of 4-demethyl-4-deoxypodophyllotoxin, N-(1-oxyl-4-demethyl- 4-deoxypodophyllic)-α-amino acids amides, were synthesized and evaluated for antiproliferative activity and cell cycle effects. These synthesized compounds proved to be more hydrophilic, as well as improved or comparable in vitro cytotoxicities against four cell lines (A-549, HeLa, SiHa, and HL-60) compared with either parent DPT or anti-cancer drug VP-16. Furthermore, flow cytometric analysis exhibited that N-(1-oxyl-4-demethyl-4-deoxypodophyllic)-d-α-methine amide (15f) induced cell cycle arrest in the G2/M phase in A-549 cells.

Synthesis of hybrid 4-deoxypodophyllotoxin–5-fluorouracil compounds that inhibit cellular migration and induce cell cycle arrest

A series of deoxypodophyllotoxin-5-fluorouracil hybrid compounds were synthesized, and their cytotoxic activity was evaluated using four human cancer cell lines (HeLa, A549, HCT-8, and HepG2) and the human normal cell line WI-38. The synthesized compounds exhibited greater cytotoxic activity in tumor cells and reduced toxicity in the normal cell line compared with the anticancer drug VP-16 and 5-FU. Additionally, the most potent of these compounds-4-O-demethyl-4-deoxypodophyllotoxin-4-yl 4-((6-(2-(5-fluorouracil-yl) acetamido) hexyl) amino)-4-oxobutanoate (compound 22)-induced cell-cycle arrest in the G2/M phase by regulating levels of cdc2, cyclinB1, and p-cdc2 in A549 cells. Furthermore, compound 22 may inhibited the migration of A549 cells via down-regulation of MMP-9 and up-regulation of TIMP-1.

Synthesis and biological evaluation of 2,4-diaminopyrimidines as selective Aurora A kinase inhibitors

The Aurora kinases are a family of serine/threonine kinases that interact with components of the mitotic apparatus and serve as potential therapeutic targets in oncology. Here we synthesized 15 2,4-diaminopyrimidines and evaluated their biological activities, including antiproliferation, inhibition against Aurora kinases and cell cycle effects. These compounds generally exhibited more potent cytotoxicity against tumor cell lines compared with the VX-680 control, especially compound 11c, which showed the highest cytotoxicities, with IC50 values of 0.5-4.0xa0μM. Compound 11c had more than 35-fold more selectivity for Aurora A over Aurora B, and molecular docking analysis indicated that compound 11c form better interaction with Aurora A both from the perspective of structure and energy. Furthermore, compound 11c induced G2/M cell cycle arrest in HeLa cells. This series of compounds has the potential for further development as selective Aurora A inhibitors for anticancer activity.

Synthesis and biological evaluation of norcantharidin derivatives as protein phosphatase-1 inhibitors

Cantharidin and norcantharidin display anticancer activity against a broad range of tumor cell lines. In this study, we have synthesized a series of norcantharidin derivatives and evaluated their cytotoxic effects on four human tumor cell lines together with the genetically normal human diploid fibroblast line WI-38. One of our compounds (1S,4R)-3-((4-(4-(4-fluorophenyl)piperazin-1-ylsulfonyl) phenyl)carbamoyl)-7-oxa-bicyclo[2.2.1]heptane-2-carboxylic acid (12) exhibited potent cytotoxic effects on the tumor cell lines A-549, HepG2, HeLa, and HCT-8, whereas it was less toxic to WI-38 cells than its parent compound, norcantharidin. In addition, this compound inhibited protein phosphatase-1 activity and microtubule formation in HeLa cells, and it also interacts with calf thymus DNA.

One-pot synthesis and biological evaluation of N-(aminosulfonyl)-4-podophyllotoxin carbamates as potential anticancer agents

A series of N-(aminosulfonyl)-4-podophyllotoxin carbamates were synthesized via the Burgess-type intermediate, and their antiproliferative activities were evaluated. Most of them possessed more potent cytotoxic effects against four human tumor cell lines (HeLa, A-549, HCT-8 and HepG2) and less toxic to normal human fetal lung fibroblast WI-38 cells than etoposide. In particular, N-(morpholinosulfonyl)-4-podophyllotoxin carbamate (9) exhibited the most potent activity towards these four tumor cells with IC50 values in the range of 0.5-16.5μM. Furthermore, immunofluorescence analysis revealed that 9 induced cell apoptosis by up-regulating the expression of p53 and ROS. Meanwhile, 9 effectively inhibited tubulin polymerization and microtubule assembly at cellular levels in HeLa cells. In addition, 9 could induce cell cycle arrest in the G2/M phase in HeLa cells by up-regulating levels of cyclinB1 and cdc2 and decreasing the expression of p-cdc2. These results indicated that 9 had potential for further development as anticancer agents.

Conjugates of podophyllotoxin and norcantharidin as dual inhibitors of topoisomeraseII and protein phosphatase 2A.

A series of novel conjugates of podophyllotoxin and norcantharidin was designed using association strategy, and synthesized by coupling 4-demethylepipodophyllotoxin with N-amino acid norcantharimides, and their cytotoxicitiy was evaluated against four human tumor cell lines (A-549, HepG2, HeLa and HCT-8) and normal human diploid fibroblast line WI-38. These compounds exhibited potent cytotoxic effects on tumor cell lines, whereas it was less toxic to WI-38xa0cells than anticancer drug VP-16 or its parent compound norcantharidin. Furthermore, conjugates 7a, 7c, 7f, 7j, 7k and 7l displayed excellent PP2A inhibition activity with IC50 values of 0.49-9.52xa0μM. The most potent compound 7l also exhibited topoisomeraseⅡinhibition activity. In addition, compound 7l induced cell-cycle arrest in the G2/M phase in HepG2 by regulating levels of cyclinB1 and cdc2.

Investigation of the anti-angiogenesis effects induced by deoxypodophyllotoxin-5-FU conjugate C069 against HUVE cells.

We have found that the deoxypodophyllotoxin-5-fluorouracil conjugate, 4-O-demethyl-4-deoxyppodophyllotoxin-4-yl 4-((6-(2-(5-fluorouracil-yl)acetamido) hexyl)amino)-4-oxobutanoate (C069), possessed superior cytotoxicities and less toxicity compared with etoposide. In this paper, the anti-angiogenic and vascular disrupting activities of C069 were examined with several in vitro and in vivo models. First, we demonstrated that C069 significantly inhibited the proliferation, migration, tube formation and disrupted the formed tube-like structures of HUVE cells, and inhibited angiogenesis in chicken chorioallantoic membrane assay. Furthermore, we found that C069 inhibited tube formation of HUVE cells by down-regulating the MMP-2, MMP-9, and phosphorylation of Akt and β-catenin. These results provided the initial evidence that C069 exerts potent anti-angiogenic and vascular disrupting effects.

Synthesis and biological evaluation of 4β-(thiazol-2-yl)amino-4′-O-demethyl-4-deoxypodophyllotoxins as topoisomerase-II inhibitors

A series of 4β-(thiazol-2-yl)amino-4-O-demethyl-4-deoxypodophyllotoxins were synthesized, and their cytotoxicities were evaluated against four human cancer cell lines (A549, HepG2, HeLa, and LOVO cells) and normal human diploid fibroblast line WI-38. Some of the compounds exhibited promising antitumor activity and less toxicity than the anticancer drug etoposide. Among them, compounds 15 and 17 were found to be the most potent synthetic derivatives as topo-II inhibitors, and induced DNA double-strand breaks via the p73/ATM pathway as well as the H2AX phosphorylation in A549 cells. These compounds also arrested A549 cells cycle in G2/M phase by regulating cyclinB1/cdc2(p34). Taken together, these results show that a series of compounds are potential anticancer agents.