A novel STAT3 inhibitor HO-3867 induces cell apoptosis by reactive oxygen species-dependent endoplasmic reticulum stress in human pancreatic cancer cells.

Pancreatic cancer is the most commonly diagnosed malignancy among solid tumors and has shown an increasing trend year by year. Thus, there is an urgent need for the discovery of new anticancer drugs for the treatment of pancreatic cancer. In recent years, it has been reported that the compound HO-3867, a novel analog of the natural product curcumin, showed antitumor activity with low toxicity. However, the underlying mechanism of this compound's attack on cancer cells is not very clear. In the present study, it was found that HO-3867 showed good antitumor activity at the concentration of 2 µmol/l in PANC-1 and BXPC-3 cells. Importantly, it was also found that HO-3867 treatment significantly induced reactive oxygen species (ROS) production in human pancreatic cancer cell lines, inducing PANC-1 and BXPC-3 cells. Co-treatment with the ROS scavenger, N-acetyl cysteine, partially abrogated HO-3867-induced cell apoptosis. The activation of mitogen-activated protein kinase and endoplasmic reticulum stress indicated a downstream event of ROS generation in mediating the anticancer effect of the HO-3867. In addition, independent of the ROS pathway, direct STAT3 inhibition was observed in HO-3867-induced cell apoptosis. Taken together, the results of this work suggest that both the ROS-dependent ER stress and STAT3 pathways were implicated in the cell apoptosis induced by the novel compound HO-3867.

Da0324, an inhibitor of nuclear factor-κB activation, demonstrates selective antitumor activity on human gastric cancer cells.

BACKGROUND: The transcription factor nuclear factor-κB (NF-κB) is constitutively activated in a variety of human cancers, including gastric cancer. NF-κB inhibitors that selectively kill cancer cells are urgently needed for cancer treatment. Curcumin is a potent inhibitor of NF-κB activation. Unfortunately, the therapeutic potential of curcumin is limited by its relatively low potency and poor cellular bioavailability. In this study, we presented a novel NF-κB inhibitor named Da0324, a synthetic asymmetric mono-carbonyl analog of curcumin. The purpose of this study is to research the expression of NF-κB in gastric cancer and the antitumor activity and mechanism of Da0324 on human gastric cancer cells. METHODS: The expressions between gastric cancer tissues/cells and normal gastric tissues/cells of NF-κB were evaluated by Western blot. The inhibition viability of compounds on human gastric cancer cell lines SGC-7901, BGC-823, MGC-803, and normal gastric mucosa epithelial cell line GES-1 was assessed with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Absorption spectrum method and high-performance liquid chromatography method detected the stability of the compound in vitro. The compound-induced changes of inducible NF-κB activation in the SGC-7901 and BGC-823 cells were examined by Western blot analysis and immunofluorescence methods. The antitumor activity of compound was performed by clonogenic assay, matrigel invasion assay, flow cytometric analysis, Western blot analysis, and Hoechst 33258 staining assay. RESULTS: High levels of p65 were found in gastric cancer tissues and cells. Da0324 displayed higher growth inhibition against several types of gastric cancer cell lines and showed relatively low toxicity to GES-1. Moreover, Da0324 was more stable than curcumin in vitro. Western blot analysis and immunofluorescence methods showed that Da0324 blocked NF-κB activation. In addition, Da0324 significantly inhibited tumor proliferation and invasion, arrested the cell cycle, and induced apoptosis in vitro. CONCLUSION: The asymmetric mono-carbonyl analog of curcumin Da0324 exhibited significantly improved antigastric cancer activity. Da0324 may be a promising NF-κB inhibitor for the selective targeting of cancer cells. However, further studies are needed in animals to validate these findings for the therapeutic use of Da0324.

Design, synthesis, and anticancer evaluation of long-chain alkoxylated mono-carbonyl analogues of curcumin.

Curcumin is a nontoxic phenolic compound that modulates the activity of several cellular targets that have been linked with cancers and other chronic diseases. However, the efficacy of curcumin in the clinic has been limited by its poor bioavailability and rapid metabolism in vivo. We have previously reported the design and discovery of series of 5-carbon linker-containing mono-carbonyl analogues of curcumin (MACs) as anti-cancer agents. In continuation of our ongoing research, we designed and synthesized 37 novel long-chain alkoxylated MACs for anti-cancer evaluation here. The MTS assay was used to determine the cytotoxicity of compounds in gastrointestinal cancer cells. Compounds 5, 28, and 29 showed strongest inhibition against gastric cancer cell proliferation and were subjected to further analysis. The effects of 5, 28, and 29 on cell apoptosis were measured by flow cytometry. Expression levels of Bcl-2, cleaved poly ADP-ribose polymerase (PARP), and pro-caspase-3 were detected by western blotting. Compounds 5, 28, and 29 induced apoptosis in human gastric carcinoma cells, increased PARP cleavage, and decreased expression of Bcl-2 and pro-caspase-3 protein. We then showed that compound 28, which possessed the strongest activity among the test compounds in vitro, exhibited significant tumor inhibition in SGC7901-driven xenograft mouse model. Taken together, the novel compound 28 could be further explored as an effective anticancer agent for the treatment of human gastric cancer.

Synthesis and biological evaluation of a novel class of curcumin analogs as anti-inflammatory agents for prevention and treatment of sepsis in mouse model.

A novel class of asymmetric mono-carbonyl analogs of curcumin (AMACs) were synthesized and screened for anti-inflammatory activity. These analogs are chemically stable as characterized by UV absorption spectra. In vitro, compounds 3f, 3m, 4b, and 4d markedly inhibited lipopolysaccharide (LPS)-induced expression of pro-inflammatory cytokines tumor necrosis factor-α and interleukin-6 in a dose-dependent manner, with IC50 values in low micromolar range. In vivo, compound 3f demonstrated potent preventive and therapeutic effects on LPS-induced sepsis in mouse model. Compound 3f downregulated the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 MAPK and suppressed IκBα degradation, which suggests that the possible anti-inflammatory mechanism of compound 3f may be through downregulating nuclear factor kappa binding (NF-κB) and ERK pathways. Also, we solved the crystal structure of compound 3e to confirm the asymmetrical structure. The quantitative structure-activity relationship analysis reveals that the electron-withdrawing substituents on aromatic ring of lead structures could improve activity. These active AMACs represent a new class of anti-inflammatory agents with improved stability, bioavailability, and potency compared to curcumin. Our results suggest that 3f may be further developed as a potential agent for prevention and treatment of sepsis or other inflammation-related diseases.

Design, Synthesis, and Biological Evaluation of Novel Quinazoline Derivatives as Anti-inflammatory Agents against Lipopolysaccharide-induced Acute Lung Injury in Rats.

Quinazoline has been reported to exhibit multiple bioactivities. The aim of this study was to discover new quinazoline derivatives with preventive effect on lipopolysaccharide-induced acute lung injury via anti-inflammatory actions. Thirty-three 4-amino quinazolin derivatives were synthesized and screened for anti-inflammatory activities in lipopolysaccharide-induced macrophages. The most potent four compounds, 6h, 6m, 6p, and 6q, were shown dose-dependent inhibition against lipopolysaccharide-induced TNF-α and IL-6 release. Then, the preliminary structure-activity relationship and quantitative structure-activity relationship analyses were conducted. To further determine the effects of quinazolines on acute lung injury treatment, lipopolysaccharide-induced acute lung injury model was employed. Male Sprague Dawley rats were pretreated with 6m or 6q before instillation of lipopolysaccharide. The results showed that 6m and 6q, especially 6q, obviously alleviated lung histopathological changes, inflammatory cells infiltration, and cytokines mRNA expression initiated by lipopolysaccharide. Taken together, this work suggests that 6m and 6q suppressed the lipopolysaccharide-induced acute lung injury through inhibition of the inflammatory response in vivo and in vitro, indicating that quinazolines might serve as potential agents for the treatment of acute lung injury and deserve the continuing drug development and research.

An efficient synthesis of chiral diamines with rigid backbones: application in enantioselective Michael addition of malonates to nitroalkenes.

A new and efficient route for synthesis of enantiomerically pure biisoindoline and its isomer based on the diaza-Cope rearrangement reaction with chiral 1,2-bis(2-hydroxylphenyl)-1,2-diaminoethane as starting material has been developed. The newly prepared biisoindoline was employed as a chiral ligand in the Ni(II)-catalyzed enantioselective Michael addition of malonates to conjugated nitroalkenes, and good to excellent enantioselectivities were obtained.