Easy access on water: A cobalt‐catalyzed asymmetric preparation of trifluoromethylcyclopropanes has been developed that yields high enantioselectivities with a broad range of styrene substrates (see scheme). The reaction presents a new access to enantioenriched CF3‐containing building blocks.

Hepatitis B virus X protein (HBx) is closely involved in the development of hepatocellular carcinoma, a highly vascularized solid tumor. Here we show that HBx increases the transcriptional activity and protein level of hypoxia-inducible factor-1alpha (HIF-1alpha) under both normoxic and hypoxic conditions, and it also stimulates angiogenesis. HBx directly interacted with the bHLH/PAS domain of HIF-1alpha but not with the von Hippel-Lindau protein (pVHL). HBx decreased the binding of pVHL to HIF-1alpha and prevented ubiquitin-dependent degradation of HIF-1alpha. In HBx-transgenic mice, HIF-1alpha and vascular endothelial growth factor were strongly detected in the dysplastic lesion, where HBx was also more highly expressed than in the non-neoplastic region of the liver. An immunohistochemical study showed that microvessels are more abundant in the dysplastic lesion than in the non-neoplastic region. Our data suggest that HBx stabilizes HIF-1alpha and leads to angiogenesis during hepatocarcinogenesis.

Abstract[6]-Gingerol, a natural component of ginger, exhibits antiinflammatory and antitumorigenic activities. Despite its potential efficacy in cancer, the mechanism by which [6]-gingerol exerts its chemopreventive effects remains elusive. The leukotriene A 4 hydrolase (LTA 4 H) protein is regarded as a relevant target for cancer therapy. Our in silico prediction using a reverse-docking approach revealed that LTA 4 H might be a potential target of

The sustained expansion of a tumor mass requires new blood vessel formation to provide rapidly proliferating tumor cells with an adequate supply of oxygen and nutrients. Hypoxia-inducible factor-1 (HIF-1) plays an essential role in tumor angiogenesis and growth by regulating the transcription of genes in response to hypoxic stress. This study was designed to investigate the effects of melatonin on tumor growth and angiogenesis, as well as the mechanism underlying the antitumor activities of melatonin. In this study, we show that the administration of melatonin inhibits tumor growth and blocks tumor angiogenesis in mice. Moreover, melatonin diminished the expression of the HIF-1α protein within the tumor mass during tumorigenesis. Our findings suggest that melatonin is a promising anti-angiogenic therapeutic agent targeting HIF-1α in cancer. Considering that HIF-1α is overexpressed in a majority of human cancers, melatonin could offer a potent therapeutic agent for cancer.

The anticancer effects of red wine have attracted considerable attention. Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a well-known polyphenolic compound of red wine with cancer chemopreventive activity. However, the basis for this activity is unclear. We studied leukotriene A4 hydrolase (LTA4H) as a relevant target in pancreatic cancer. LTA4H knockdown limited the formation of leukotriene B4 (LTB4), the enzymatic product of LTA4H, and suppressed anchorage-independent growth of pancreatic cancer cells. An in silico shape similarity algorithm predicted that LTA4H might be a potential target of resveratrol. In support of this idea, we found that resveratrol directly bound to LTA4H in vitro and in cells and suppressed proliferation and anchorage-independent growth of pancreatic cancer by inhibiting LTB4 production and expression of the LTB4 receptor 1 (BLT1). Notably, resveratrol exerted relatively stronger inhibitory effects than bestatin, an established inhibitor of LTA4H activity, and the inhibitory effects of resveratrol were reduced in cells where LTA4H was suppressed by shRNA-mediated knockdown. Importantly, resveratrol inhibited tumor formation in a xenograft mouse model of human pancreatic cancer by inhibiting LTA4H activity. Our findings identify LTA4H as a functionally important target for mediating the anticancer properties of resveratrol.

BackgroundMethamphetamine (METH) is a commonly abused drug that may result in neurotoxic effects. Recent studies have suggested that involvement of neuroinflammatory processes in brain dysfunction is induced by misuse of this drug. However, the mechanism underlying METH-induced inflammation and neurotoxicity in neurons is still unclear. In this study, we investigated whether asiatic acid (AA) effected METH-mediated neuroinflammation and neurotoxicity in dopaminergic neuronal cells. And we further determined whether the effect involved in the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription (STAT)3 and extracellular signal-regulated kinase (ERK) pathway.MethodsWe used the human dopaminergic neuroblastoma SH-SY5Y cell line, murine microglial BV2 cell line, and primary culture of rat embryo mesencephalic neurons. Pro-inflammatory cytokine production was monitored by ELISA and RT/real-time PCR. The cell cycle distribution and mitochondrial membrane integrity was analyzed by flow cytometry. We used immunoblotting, DNA-binding activity, and immunofluorescence staining to analyze the effect of AA on activation of the NF-κB, STAT3, MAPK-ERK, and apoptosis signaling pathways.ResultsMETH induced TNF receptor (TNFR) expression and led to morphological changes of cells. Additionally, this drug increased pro-inflammatory cytokine (TNFα and IL-6) expression. AA significantly suppressed METH-induced TNFR expression in concentration dependent. Increased secretion of TNFα and IL-6 was inhibited in METH-stimulated neuronal cells by AA administration. AA showed significant protection against METH-induced translocation of NF-κB/STAT3 and ERK phosphorylation. AA inhibited METH-induced proteolytic fragmentation of caspase-3 and PARP. The pro-apoptotic protein Bax was significantly decreased, while the anti-apoptotic protein Bcl-xL was increased by AA treatment in METH-stimulated cells. A similar protective effect of AA on mitochondrial membrane integrity was also confirmed by flow cytometry and immunofluorescence staining.ConclusionsBased on the literatures and our findings, AA is a promising candidate for an anti-neurotoxic agent, and it can potentially be used for the prevention and treatment of various neurological disorders.Electronic supplementary materialThe online version of this article (10.1186/s12974-017-1009-0) contains supplementary material, which is available to authorized users.

During mammalian embryogenesis, the early embryo grows in a relatively hypoxic environment due to a restricted supply of oxygen. The molecular mechanisms underlying modulation of self-renewal and differentiation of mouse embryonic stem cells (mESCs) under such hypoxic conditions remain to be established. Here, we show that hypoxia inhibits mESC self-renewal and induces early differentiation in vitro, even in the presence of leukemia inhibitory factor (LIF). These effects are mediated by down-regulation of the LIF-STAT3 signaling pathway. Under conditions of hypoxia, hypoxia-inducible factor-1␣ (HIF-1␣) suppresses transcription of LIF-specific receptor (LIFR) by directly binding to the reverse hypoxia-responsive element located in the LIFR promoter. Ectopic expression and small interference RNA knockdown of HIF-1␣ verified the inhibitory effect on LIFR transcription. Our findings collectively suggest that hypoxia-induced in vitro differentiation of mESCs is triggered, at least in part, by the HIF-1␣-mediated suppression of LIF-STAT3 signaling. Analysis of mESCs2 isolated from the inner cell mass of preimplantation embryos has aided in elucidating the early molecular events and mechanisms responsible for maintenance of ESC pluripotency (1). In contrast to human ESCs (hESCs), selfrenewal of mESCs can be sustained indefinitely in feeder-free conditions if supplemented with LIF (2). mESC lines can be derived directly from embryos in the presence of LIF, indicating that this factor is specifically required for the maintenance of pluripotency. Intracellular signaling cascades initiated by LIF are mediated through the heterodimerization of LIFR and glycoprotein 130 (gp130). This complex activates Janus-associated tyrosine kinase and the signal transducer and activator of transcription 3 (STAT3) signaling pathway. Activation of STAT3 by LIF is crucial in mediating self-renewal signals in mESCs (3, 4).During mammalian development, oxygen needed for cellular metabolism in the early embryo is supplied by simple diffusion from fluids within the oviduct and uterus. Thus, the early embryo develops in a relatively hypoxic environment until the onset of vascularization after implantation (5). Actually, oxygen tension in the mammalian reproductive tract is reported to be less than half the atmospheric oxygen tension (6). Low oxygen tension triggers a wide range of cellular events centered on the regulation of hypoxia-inducible factor-1 (HIF-1) (7), which consists of a common ␤ subunit (HIF-1␤) and an oxygen-sensitive ␣ subunit (HIF-1␣). Under normoxia, HIF-1␣ is rapidly degraded via the von Hippel-Lindau protein-mediated ubiquitin-proteasome pathway (8). Although the role and biological relevance of HIF-1 during murine embryonic development have been established (9 -11), our understanding of how HIF-1 affects the early differentiation of mESCs at the molecular level is beginning to emerge.Our previous study demonstrated the presence of hypoxic regions during normal mouse development (12), which prompted us to study the role of hy...

Abstract. Thymoquinone (TQ), a compound isolated from black seed oil (Nigella sativa), has been reported to possess anti-inflammatory and anticancer activities. However, the molecular mechanisms underlying the anticancer effects of TQ remain poorly understood. In the present study, we found that TQ significantly reduced the viability of human colon cancer HCT116 cells in a concentration-and time-dependent manner. Treatment of cells with TQ induced apoptosis, which was associated with the upregulation of Bax and inhibition of Bcl-2 and Bcl-xl expression. TQ also activated caspase-9,-7, and -3, and induced the cleavage of poly-(ADP-ribose) polymerase (PARP). Pretreatment with a pan-caspase inhibitor, z-VAD-fmk, abrogated TQ-induced apoptosis by blocking the cleavage of caspase-3 and PARP. Treatment of cells with TQ also diminished the constitutive phosphorylation, nuclear localization and the reporter gene activity of signal transducer and activator of transcription-3 (STAT3). TQ attenuated the expression of STAT3 target gene products, such as survivin, c-Myc, and cyclin-D1, -D2, and enhanced the expression of cell cycle inhibitory proteins p27 and p21. Treatment with TQ attenuated the phosphorylation of upstream kinases, such as Janus-activated kinase-2 (JAK2), Src kinase and epidermal growth factor receptor (EGFR) tyrosine kinase. Pharmacological inhibition of JAK2 and Src blunted tyrosine phosphorylation of EGFR and STAT3, while treatment with an EGFR tyrosine kinase inhibitor gefitinib inhibited phosphorylation of STAT3 without affecting that of JAK2 and Src in HCT116 cells. Collectively, our study revealed that TQ induced apoptosis in HCT116 cells by blocking STAT3 signaling via inhibition of JAK2-and Src-mediated phosphorylation of EGFR tyrosine kinase. IntroductionColorectal cancer is one of the leading causes of mortality and ranks among the three most common cancers in developed countries (1,2). More than one million new cases of colorectal cancer are diagnosed every year (3). Multiple lines of evidence suggest that bioactive compounds present in various edible and medicinal plants can prevent colon carcinogenesis (4). Thymoquinone (TQ; Fig. 1A), a dietary phytochemical, is the major bioactive constituent present in black seed oil (Nigella sativa), which is widely consumed as a condiment and has long been used in Ayurvedic medicine. TQ has been reported to exert antioxidative, anti-inflammatory and anticancer effects (5-7). Several studies have reported that TQ inhibits cell proliferation, induces apoptosis and impedes the in vivo growth of xenograft tumors of various human cancer cells including those of the stomach (8,9), colorectal (10,11), lungs (12), breast (5) and prostate (13). In a recent study, TQ was shown to inhibit 1,2-dimethylhydrazine-induced initiation and promotion of colon carcinogenesis in Wister rats (14). However, the molecular basis of the anticancer effects of TQ in colon cancer has yet to be fully elucidated.Evasion from apoptosis is one of the hallmarks of cancer (15). Tumor cells ...