Design, synthesis and biological evaluation of dipeptides as novel non-covalent 20S proteasome inhibitors.

Based on the interaction modes of the natural 20S proteasome inhibitors TMC-95A, we have previously discovered a dipeptide 1. To explore the SAR around compound 1, we designed and synthesized a series of dipeptides (8-38) with a fragment-based strategy. Among them, nine compounds showed significant inhibitory activities against the chymotrypsin-like activity of human 20S proteasome with IC50 values at the submicromolar level, which were comparable or even superior to the parent compound 1. Meanwhile, they displayed no significant inhibition against trypsin-like and caspase-like activities of 20S proteasome. The results suggested the feasibility to design dipeptides as novel and potent 20S proteasome inhibitors.[Formula: see text].

Silencing of long non-coding RNA CRNDE promotes autophagy and alleviates neonatal hypoxic-ischemic brain damage in rats.

Hypoxic-ischemic (HI) brain damage (HIBD) leads to high neonatal mortality and severe neurologic morbidity. Autophagy is involved in the pathogenesis of HIBD. This study aims to investigate the effect of long non-coding RNA colorectal neoplasia differentially expressed (CRNDE) on HIBD and to validate whether autophagy is involved in this process. A HIBD model in rat pups and a HI model in rat primary cerebrocortical neurons were established. Autophagy was evaluated by western blot. The HIBD in rats was evaluated by hematoxylin and eosin staining, TUNEL staining, triphenyl tetrazolium chloride staining, and morris water maze test. The HI injury in vitro was evaluated by determining cell viability and apoptosis. The results showed that CRNDE expression was time-dependently increased in the brain after HIBD. Administration with CRNDE shRNA-expressing lentiviruses alleviated pathological injury and apoptosis in rat hippocampus, decreased infarct volume, and improved behavior performance of rats subjected to HIBD. Furthermore, CRNDE silencing promoted cell viability and inhibited cell apoptosis in neurons exposed to HI. Moreover, CRNDE silencing promoted autophagy and the autophagy inhibitor 3-methyladenine counteracted the neuroprotective effect of CRNDE silencing on HI-induced neuronal injury both in vivo and in vitro. Collectively, CRNDE silencing alleviates HIBD, at least partially, through promoting autophagy.

Long non-coding RNA CRNDE deteriorates intrauterine infection-induced neonatal brain injury.

BACKGROUND: This study aimed to test the hypothesis that long non-coding RNA (lncRNA) colorectal neoplasia differentially expressed (CRNDE) could exacerbate brain injury caused by intrauterine infection in neonatal rats. METHODS: Intrauterine infection was induced in pregnant rats by lipopolysaccharide (LPS). After delivery, newborn rats with brain injury caused by intrauterine infection were randomly divided into control, control shRNA, and CRNDE shRNA groups. CRNDE expression in serum and amniotic fluid of pregnant rats and neonatal brain tissues were determined by quantitative real-time PCR (qRT-PCR). Morris water maze (MWM) task was used to test the spatial learning and memory ability. Histological examination and apoptosis detection were performed by hematoxylin and eosin (H&E) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, respectively. Immunohistochemistry was conducted to evaluate the activation of astrocytes and microglia. RESULTS: LncRNA CRNDE was highly expressed in serum and amniotic fluid of maternal rats and in brain tissues of offspring rats. Furthermore, shRNA-mediated CRNDE downregulation could rescue the spatial learning and memory ability, improve brain histopathological changes and cell death, and inhibit the activation of astrocytes and microglia caused by LPS. CONCLUSION: CRNDE silencing possessed a cerebral protective effect in neonatal rats with brain injury caused by interauterine infection.

Epidemiologic and etiologic characteristics of hand, foot, and mouth disease in Chongqing, China between 2010 and 2013.

Hand, foot, and mouth disease (HFMD) has become very common in children, with widespread occurrence across China. The aim of this study was to investigate the epidemiologic and etiologic characteristics of HFMD, including etiologic variations in Chongqing, China. An epidemiologic investigation was based on 3,472 patients who presented with HFMD manifestations and were admitted at the Children's Hospital of Chongqing Medical University between 2010 and 2013. Fecal specimens from 830 patients were analyzed by nested RT-PCR to identify the enterovirus pathogens, and the molecular characterization of HFMD was illustrated by phylogenetic tree analysis. The results of this study indicate that the peak of the HFMD epidemic in Chongqing between 2010 and 2013 occurred between April and July each year. The median age of onset was 2.24 years old, and children under the age of five accounted for 96.4% of all the HFMD cases; the male-to-female ratio was 1.89:1. Enterovirus 71 accounted for a major proportion of the isolated strains every year, including the majority (74%) of severe cases. However, the proportion of Coxsackie A (CV-A) 6 infections increased from 2.11% in 2010 to 16.36% in 2013, while the proportion of CV-A16 infections decreased from 31.23% in 2010 to 4.67% in 2013. Molecular epidemiologic study showed that all enterovirus 71 strains belonged to subgenotype C4a, whereas all CV-A16 strains belonged to genotype B1, including subgenotype B1a and subgenotype B1b.

[Olaparib potentiates the antitumor effect of Taxol on 4T1 breast cancer].

Poly (ADP-ribose) polymerase 1/2 (PARP1/2) can catalyze the poly (ADP ribose) (PAR) substrate protein modification and play an important role in the regulation of DNA damage repair, cell death and transcriptional activity. The PARP inhibitor olaparib (AZD2281) can be used as a sensitizer of radiotherapy and chemotherapy in the cancer treatment. Through establishment of biological fluorescent labeled 4T1 ectopic breast tumor model, we found that olaparib exhibited a poor effect on 4T1 breast cancer alone. However, in the combination with Taxol, olaparib significantly increased the anti-tumor effect of Taxol, and reduced the PAR levels of the tumor tissues. Importantly, olaparib did not amplify the toxicity of chemotherapy drugs. This study suggests that olaparib is a representative of the PARP inhibitor that can enhance Taxol's antitumor effect in the 4T1 ectopic breast tumor model, which sets the foundation for future study of the mechanism of olaparib action.

[Establishment of a glioma orthotopic xenograft model based on imaging technology].

Orthotopic xenograft model of human brain cancer cells is a good preclinical model for evaluation of antitumor compounds. In the present study, an orthotopic xenograft model of U87MG-m Cherry-luc was established in Balb/c nude mice and the tumor growth was monitored via imaging technology including magnetic resonance imaging (MRI), in vivo imaging (IVI) and micro-CT. Furthermore, the model was evaluated with a positive drug temozolomide. Our data suggest that integrated imaging technology including MRI, IVI and micro-CT in orthotopic xenograft model can be used to facilitate monitoring of cancer progression and evaluate antitumor activity of drugs against glioma.

LB-1 Exerts Antitumor Activity in Pancreatic Cancer by Inhibiting HIF-1α and Stat3 Signaling.

Hypoxia is widely present in pancreatic cancer and subsequently causes the overexpression of hypoxia-inducible factor-1α (HIF-1α) and signal transducer and activator of transcription-3 (Stat3). HIF-1α and Stat3 function cooperatively to regulate a number of downstream genes that are implicated in tumorigenesis. Thus, inhibition of HIF-1α and Stat3 is a potential therapeutic strategy for pancreatic cancer. In this study, we explored how LB-1, a novel triptolide (LA) derivative, exerted its antitumor effect through blockade of HIF-1α and Stat3 signaling. Our data showed that LB-1 was able to inhibit the proliferation and colony formation of Mia-PaCa2 and SW1990 cells. LB-1 suppressed HIF-1α protein accumulation by promoting its proteasome degradation and reducing transactivation. Moreover, the silence of HIF-1α by shRNA partially prevented the proliferation inhibition triggered by LB-1. As expected, LB-1 also decreased Stat3 protein accumulation and blocked the physical interactions between HIF-1α/p300/phosphor-Stat3 (p-Stat3) at the pharmacological concentration to reduce VEGF expression, thereby hypoxia-induced angiogenesis. In the Mia-PaCa2 nude xenograft model, therapeutic treatment with LB-1 significantly inhibited tumor growth and had minimal systemic toxicity compared to the mother drug LA. Furthermore, in accordance with in vitro results, HIF-1α activation and Stat3 expression in tumors were blocked by LB-1 through mTOR-dependent pathway. Taken together, these results illustrate that, as a potent inhibitor of HIF-1α and Stat3 signaling, LB-1 exhibits antitumor effect and could be potentially used to treat pancreatic cancer.

[Research progress of hypoxia-inducible factor 1 inhibitors against tumors].

Hypoxia occurs in chronic and acute vascular diseases and tumor formation. The ability of tumor cells to maintain a balance between an adaptation to hypoxia and cell death is regulated by a family of transcription factors called hypoxia-inducible factor 1 (HIF-1). Tumor hypoxia mediated by HIF-1 would facilitate the likelihood of resistance to chemotherapy and radiotherapy, proliferation, metastasis and the invasive potential; all of which culminate in a decrease in patient survival. And HIF-1 alpha subunit decides the activity of HIF-1, which is regulated by oxygen. So understanding the role of HIF in signal pathway, drug resistance mechanism and its feature is crucial for developing novel anticancer therapies. In recent years, more attentions have focused on HIF-1 alpha inhibitors. It is expected that development of more potent and selective HIF inhibitors will provide an effective treatment of cancer and other HIF-related diseases. So we will focus on the biological characteristics and mechanism of HIF-1 to review currently studied HIF-1 inhibitors.

[Development of a novel screening assay for inhibitors targeting HIF-1alpha and P300 interaction].

Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.

[A novel HIF-1 inhibitor--manassantin A derivative LXY6099 inhibits tumor growth].

Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor on hypoxia responses in mammalian tissues. HIF-1 plays as a positive factor in solid tumor and leads to hypoxia-driven responses that enhance its downstream gene expression for tumor growth and survival. LXY6099 was obtained by the structural modification and optimization of manassantin A (MA) as a high potent HIF-1 inhibitor. Antitumor activity of LXY6099 was observed in this study. LXY6099 with an IC50 value of 2.46 x 10(-10) mol x L(-1) showed more sensitive inhibition activity to HIF-1 than that of MA detected by reporter gene assay (> 100 folds). It showed strong inhibition on the growth of human solid tumor cell lines. Furthermore, LXY6099 exhibited significant antitumor activity against established human tumor xenografts in nu/nu mice with treatment of MX-1 breast cancer. Thus, LXY6099 as a novel HIF-1 inhibitor could be further developed into anti-cancer agents.

[Screening and identification of the upregulators of ATP-binding cassette transporter A1].

ATP-binding cassette transporter A1 (ABCA1) promotes cholesterol and phospholipid efflux from cells to lipid-poor apolipoprotein A-I (apoA-I), and plays a key role in the initial steps of the whole process of reverse cholesterol transport (RCT). Upregulation of ABCA1 is beneficial for atherosclerosis (AS) prevention and/or therapy, which indicated that ABCA1 was a target for anti-AS drug development. In the previous study, a high-throughput screening method was established using ABCA1p-LUC HepG2 cell line to find the upregulators of ABCA1. In the present study, compound 2030421B was found using this method, with EC50 of 0.50 microg x mL(-1). The compound was further identified as an upregulator of ABCA1 expression by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting analysis. Studies also showed that the 2030421B could induce apoA-I-mediated cholesterol efflux and inhibit lipids uptake into mouse peritoneal macrophages RAW264.7.

[Gene expressions of LTC4 synthase homologs in Con A-induced mouse hepatitis and regulative effect of cyclosporine A].

OBJECTIVE: To explore the gene expressions of LTC4 synthase homologs in concanavalin A (Con A)-induced mouse hepatitis and regulation role of cyclosporine A (Cs A) treatment. METHODS: Male Balb/c mouse liver injury model was developed by iv injection of Con A (20 mg/kg) and protected by Cs A pretreatment (150 mg/kg) before Con A administration. Blood samples were collected at indicated times after Con A treatment with or without Cs A pretreatment. Liver damage was assessed by serum transaminase ALT and AST measurement and histological evaluation. Meantime, three LTC4 synthase homolog gene expressions were determined by RT-PCR. RESULTS: Serum ALT and AST upregulation were accompanied with histological damage at 2 h after Con A administration, and further aggravated at 8 h. mGST2 gene expression increased 1.7 fold at 2 h and 1.9 fold at 8 h, while the expression of LTC4 S and mGST3 changed little. Pretreatment with Cs A prevented mouse liver from injury by Con A and partly inhibited the mGST2 gene expression upregulation. CONCLUSIONS: Administration of Con A in mouse lead to a significant increase of mGST2 gene expression without any significant effect on LTC4 S and mGST3 mRNA levels. Cs A pretreatment results in protection of liver damage, whereas fails to fully inhibit the increase of mGST2 gene expression.