T-2 toxin cytotoxicity mediated by directly perturbing mitochondria in human gastric epithelium GES-1 cells.

T-2 toxin is one of the most toxic trichothecenes and harmful to human health and animal husbandry. The mechanism underlying its growth suppression remains unclear, especially for mitochondrial damage in human gastric epithelial cells. In the present study, we investigated cell death caused by T-2 toxin in a human gastric epithelial cell line (GES-1) and the possible mechanism of T-2-induced cytotoxicity. T-2 strongly reduced the viability of GES-1 cells in a time- and dose-dependent manner within a small range of concentrations. However, when the concentrations of T-2 were >40 nM, there was no concentration dependence, only time dependence. Moreover, T-2 induced apoptosis, with the activation of caspase-3 in GES-1 and mitochondrial membrane potential (MMP) decrease and cytochrome c release. T-2 also resulted in the accumulation of reactive oxygen species (ROS) and DNA damage with a positive signal of p-H2A.X in GES-1 cells. While T-2 caused a MMP decrease, DNA damage and cell death were not blocked by pretreatment with 3 mM glutathione (GSH), a typical scavenger of ROS. The induction of mitochondrial permeability transition pore (mPTP) regulators voltage-dependent anion channel (VDAC1) and cyclophilin D (CypD) were also observed in T-2-treated cells. Interestingly, cyclosporine A (CsA), a CypD inhibitor, significantly reversed the drop in MMP and the DNA damage, as well as ROS accumulation caused by T-2. Additionally, GES-1 cell death could also be protected to some extent by 4, 4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS), an inhibitor of VDAC1, especially the combination of CsA and DIDS, and 3 mM GSH could further enhance the effect of CsA + DIDS on cell viability. In conclusion, our present findings indicate that the T-2 induced MMP decrease, DNA damage and cell death, as well as ROS accumulation in GES-1 cells, starts with T-2 directly perturbing the mitochondria triggering ROS generation by acting on CypD and VDAC1. This study presents a new viewpoint for evaluating the toxicity of T-2 toxin.

Catalyst-free direct cross-dehydrogenative coupling of imidazoheterocycles with glyoxal hydrates: an efficient approach to 1,2-diketones.

An efficient and convenient methodology for catalyst-free cross-dehydrogenative coupling of imidazoheterocycles with glyoxal hydrates in good yields was developed. This methodology exhibits a broad substrate scope and excellent functional group tolerance and offers a straightforward means to produce different heterocycles such as imidazoheterocyclic quinoxaline, imidazoheterocyclic hydantoin and imidazoheterocyclic α-keto ketamine under relatively mild conditions. Biological evaluation showed that the most potent compound 3m possesses significant in vitro antiproliferative activities against human-derived lung cancer cell lines with an IC50 value of 14.8 µM.

A novel ent-kaurane diterpenoid analog, DN3, selectively kills human gastric cancer cells via acting directly on mitochondria.

Targeting mitochondria using proper pharmacological agents is considered an attractive strategy for cancer control and management. Herein, we report a newly synthetic triazole analog of Jaridonin, DN3, which exhibits more potent antitumor activity via acting directly on mitochondria. DN3 potently reduced viabilities of gastric cancer cell lines HGC-27 and MGC-803 through inducing apoptosis and cell cycle arrest. But, normal human gastric epithelial cell line GES-1 is more resistant to the growth inhibition by DN3 compared with gastric cancer cells. DN3 induced mitochondrial membrane potential (MMP) decrease and cytochrome c release in intact gastric cancer cell lines. Meanwhile, the DN3 treatment also caused the release of cytochrome c from mitochondria isolated from cancer cell lines in a mitochondrial permeability transition pore complex (PTPC) mediated manner, but not from mitochondria isolated from normal gastric epithelial cell. The induction of mitochondrial PTPC proteins voltage-dependent anion channel (VDAC) and cyclophilin D (CypD) were also observed in DN3-treated cells. More interestingly, DN3 mediated MMP decrease, release of cytochrome c, the expression of VDAC and CypD and apoptosis were blocked by the pretreatment of VDAC1 inhibitor (4, 4'-diisothiocyanatostilbene-2,2'-disulfonic acid, DIDS) and CypD inhibitor (cyclosporine A, CsA). In a mouse xenograft model of human gastric cancer, the treatment of 5 mg/kg DN3 led to significant tumor regression without affecting body weight. In conclusion, our findings indicate that DN3 is a potential agent for the treatment of gastric cancer through acting directly on mitochondria, and would be useful for us to design more and better anti-cancer compounds.

Copper-catalyzed chalcogenation of imidazoheterocycles with sulfur/selenium powder and coumarinyl triflates.

An efficient and convenient copper-catalyzed chalcogenation of imidazoheterocycles with sulfur/selenium powder and coumarinyl triflates has been described. This procedure provides a wide range of structurally diverse coumarinylthio-/coumarinylseleno-substituted imidazoheterocycles in good yields and with good functional group tolerance. Biological evaluation showed that the newly synthesized compound 6d possesses significant in vitro antiproliferative activities against human-derived esophageal, breast, stomach, and prostate cancer cell lines compared with the positive control, 5-fluorouracil.

Design and synthesis of tranylcypromine derivatives as novel LSD1/HDACs dual inhibitors for cancer treatment.

Lysine specific demethylase 1 (LSD1) and Histone deacetylases (HDACs) are promising drug targets for cancers. Recent studies reveal an important functional interplay between LSD1 and HDACs, and there is evidence for the synergistic effect of combined LSD1 and HDAC inhibitors on cancers. Therefore, development of inhibitors targeting both LSD1 and HDACs might be a promising strategy for epigenetic therapy of cancers. We report herein the synthesis of a series of tranylcypromine derivatives as LSD1/HDACs dual inhibitors. Most compounds showed potent LSD1 and HDACs inhibitory activity, especially compound 7 displayed the most potent inhibitory activity against HDAC1 and HDAC2 with IC50 of 15 nM and 23 nM, as well as potent inhibition against LSD1 with IC50 of 1.20 µM. Compound 7 demonstrated stronger anti-proliferative activities than SAHA with IC50 values ranging from 0.81 to 4.28 µM against MGC-803, MCF-7, SW-620 and A-549 human cancer cell lines. Further mechanistic studies showed that compound 7 treatment in MGC-803 cells dose-dependently increased cellular H3K4 and H3K9 methylation, as well as H3 acetylation, decreased the mitochondrial membrane potential and induced remarkable apoptosis. Docking studies showed that compound 7 can be well docked into the active binding sites of LSD1 and HDAC2. This finding highlights the potential for the development of LSD1/HDACs dual inhibitors as novel anticancer drugs.

Induction of the mitochondria-mediated apoptosis in human esophageal cancer cells by DS2, a newly synthetic diterpenoid analog, is regulated by Bax and caused by generation of reactive oxygen species.

Ent-kaurane diterpene compounds have attracted considerable attention in recent years due to its antitumor, antibacterial, and antiviral activities. However, the clinical development of natural kaurane diterpenes, for example, oridonin for cancer therapy has been hampered by its relatively moderate potency, limited bioavailability. Herein, we report a newly synthetic analog of natural ent-kaurane diterpene, DS2, which exhibits significantly improved activity of antiproliferation against various cancer cell lines relative to oridonin. DS2 treatment triggers the mitochondria-mediated apoptosis and cell cycle arrest in human esophageal cancer cell lines (EC9706, EC109). Interestingly, normal human esophageal epithelial cells (HEECs) and normal human liver cells (HL-7702) are both significantly more resistant to the growth inhibition by DS2 compared with esophageal cancer cells. The DS2-induced apoptosis in EC9706 cells correlated with the drop of mitochondrial membrane potential (MMP), release of cytochrome c into the cytosol and activation of caspase-9 and -3. The induction of proapoptotic proteins p21 and Bax were also observed in DS2-treated cells. The DS2-induced apoptosis was significantly attenuated by knockdown of Bax proteins. Meanwhile, the DS2 treatment caused generation of reactive oxygen species (ROS) in human esophageal cancer cells, but not in HEECs, which was attenuated by pretreatment with ROS scavenger N-acetylcysteine (NAC). More interestingly, the antioxidants pretreatment completely attenuated DS2 mediated loss of the MMP and apoptosis, as well as Bax expression and growth inhibition. In conclusion, the present study reveals that the mitochondria-mediated cell death by DS2 is associated with Bax regulation and ROS generation, and understanding the function and mechanism of DS2 will help us to design better anti-cancer drugs.

ALDH2*2 Allele is a Negative Risk Factor for Cerebral Infarction in Chinese Women.

Unlike its reported role in the cardiovascular diseases, little information is available for mitochondrial aldehyde dehydrogenase 2 (ALDH2) in the cerebrovascular function. We investigated the different effects of ALDH2 genotypes on the risk of cerebral infarction between the genders, because different genders had different smoking and/or dinking status which are also risk factors for cerebral infarction. 247 healthy Chinese Han people (controls, group 1), 287 Chinese Han male patients with cerebral infarction (group 2), and 82 Chinese Han female patients with cerebral infarction (group 3) were involved in this study. The frequencies of the ALDH2*2 allele in group 3 were significantly higher than those in other groups (with P = 0.001 and P = 0.002, respectively). The difference of ALDH2*2 allele frequency between group 1 and group 2 was not significant (P = 0.652). After adjustment for smoking and drinking status, the male patients without smoking or drinking status (group 4) had higher ALDH2*2 allele frequency than group 1, but the difference was still not significant (P = 0.139). Thus, we conclude that ALDH2*2 allele may be a significant negative risk factor for cerebral infarction in Chinese women [odds ratio (OR) = 2.207, 95% CI 1.416-3.439]. But for Chinese male patients, the negative effects of ALDH2*2 allele on cerebral infarction which might be concealed by other risk factors were not significant.

Jaridonin-induced G2/M phase arrest in human esophageal cancer cells is caused by reactive oxygen species-dependent Cdc2-tyr15 phosphorylation via ATM-Chk1/2-Cdc25C pathway.

Jaridonin, a novel diterpenoid from Isodon rubescens, has been shown previously to inhibit proliferation of esophageal squamous cancer cells (ESCC) through G2/M phase cell cycle arrest. However, the involved mechanism is not fully understood. In this study, we found that the cell cycle arrest by Jaridonin was associated with the increased expression of phosphorylation of ATM at Ser1981 and Cdc2 at Tyr15. Jaridonin also resulted in enhanced phosphorylation of Cdc25C via the activation of checkpoint kinases Chk1 and Chk2, as well as in increased phospho-H2A.X (Ser139), which is known to be phosphorylated by ATM in response to DNA damage. Furthermore, Jaridonin-mediated alterations in cell cycle arrest were significantly attenuated in the presence of NAC, implicating the involvement of ROS in Jaridonin's effects. On the other hand, addition of ATM inhibitors reversed Jaridonin-related activation of ATM and Chk1/2 as well as phosphorylation of Cdc25C, Cdc2 and H2A.X and G2/M phase arrest. In conclusion, these findings identified that Jaridonin-induced cell cycle arrest in human esophageal cancer cells is associated with ROS-mediated activation of ATM-Chk1/2-Cdc25C pathway.

Individuals having variant genotypes of cytochrome P450 2C19 are at increased risk of developing primary liver cancer in Han populations, without infection with the hepatitis virus.

Recently, many researchers have reported that the genetic polymorphisms of CYP2C19 may account for the interpatient variability of the clinical course in cancers including primary liver cancer (PLC). Besides the genetic polymorphisms of CYP2C19, hepatitis viruses (HV, including HAV, HBV, HCV, HDV, HEV, especially HBV and/or HCV) also account for the interpatient variability of the clinical course in PLC. This research covered the above two factors and divided the patients with PLC into two groups (one group with HBV infection and another without any HV infection) to find out whether the genetic polymorphisms of CYP2C19 have different effects in the progressing of PLC in different groups of patients. Eight hundred sixty-four cancer-free Han people (controls, named group 1), 207 Han PLC patients with HBV infection (group 2), and 55 Han PLC patients without any HV infection (group 3) were involved in this study. A wild-type allele (CYP2C19*1) and two mutated alleles (CYP2C19*2 and CYP2C19*3) were identified. The frequencies of the mutant alleles and genotypes were then compared with each other. The frequencies of the homozygous and heterozygous variant genotypes (*2/*2, *2/*3, *3/*3) in group 3 (25.5 %) were significantly higher than those in other groups (11.9 % in group 1 and 13.5 % in group 2, P = 0.014, 95 % confidence interval (CI)). The differences were statistically significant between group 1 and group 3 (P = 0.004, 95 % CI), but they were not statistically significant between group 1 and group 2 (P = 0.527, 95 % CI). Thus, we conclude that people which were not infected with HV but with the homozygous or heterozygous variant genotypes (*2/*2, *2/*3, *3/*3) of CYP2C19 may have higher possibilities of getting PLC than people with other allelic genotypes (*1/*1, *1/*2, *1/*3) (odds ratio (OR) = 2.523, 95 % CI = 1.329 ~ 4.788). However, in patients with HBV infection, the genetic polymorphisms of CYP2C19 did not seem to be an important factor in the risk of developing PLC (OR = 1.156, 95 % CI = 0.738 ~ 1.810).

Jaridonin, a novel ent-kaurene diterpenoid from Isodon rubescens, inducing apoptosis via production of reactive oxygen species in esophageal cancer cells.

Isodon rubescens, a Chinese herb, has been used as a folk, botanical medicine in China for inflammatory diseases and cancer treatment for many years. Recently, we isolated a new ent-kaurene diterpenoid, named Jaridonin, from Isodon rubescens. The chemical structure of Jaridonin was verified by infrared (IR), nuclear magnetic resonance (NMR), and mass spectrum (MS) data as well as X-ray spectra. Jaridonin potently reduced viabilities of several esophageal cancer cell lines, including EC109, EC9706 and EC1. Jaridonin treatment resulted in typical apoptotic morphological characteristics, increased the number of annexin V-positive staining cells, as well as caused a G2/M arrest in cell cycle progression. Furthermore, Jaridonin resulted in a significant loss of mitochondrial membrane potential, release of cytochrome c into the cytosol, and then activation of Caspase-9 and -3, leading to activation of the mitochondria mediated apoptosis. Furthermore, these effects of Jaridonin were accompanied by marked reactive oxygen species (ROS) production and increased expression of p53, p21(waf1/Cip1) and Bax, whereas two ROS scavengers, N-acetyl-L-cysteine (LNAC) and Vitamin C, significantly attenuated the effects of Jaridonin on the mitochondrial membrane potential, DNA damage, expression of p53 and p21(waf1/Cip1) and reduction of cell viabilities. Taken together, our results suggest that a natural ent-kaurenoid diterpenoid, Jaridonin, is a novel apoptosis inducer and deserves further investigation as a new chemotherapeutic strategy for patients with esophageal cancer.

Design and synthesis of novel 1,2,3-triazole-dithiocarbamate hybrids as potential anticancer agents.

A series of novel 1,2,3-triazole-dithiocarbamate hybrids were designed, synthesized and evaluated for anticancer activity against four selected human tumor cell lines (MGC-803, MCF-7, PC-3, EC-109). Majority of the synthesized compounds exhibited moderate to potent activity against MGC-803 and MCF-7. Among them, compounds 3a and 3c showed excellent broad spectrum anticancer activity with IC50 values ranging from 0.73 to 11.61 µM and 0.49-12.45 µM, respectively. Particularly, compound 3a was more potent than 5-fluorouracil against all tested human cancer cell lines. Flow cytometry analysis demonstrated that treatment of MGC-803 with 3c led to cell cycle arrest at G2/M phase accompanied by an increase in apoptotic cell death after 12 h.