Long noncoding RNA BC032469, a novel competing endogenous RNA, upregulates hTERT expression by sponging miR-1207-5p and promotes proliferation in gastric cancer

Long noncoding RNAs (lncRNAs) are emerging as new players in gene regulation and are associated with the development of cancers. To investigate the important role and mechanism of lncRNAs in the progression of gastric cancer, we screened lncRNAs in gastric cancer tissues and corresponding adjacent tissues, and assessed the effects on gastric cancer. Here, we report that BC032469, a novel lncRNA, expressed highly in gastric cancer tissues, and the upregulation was clinically associated with larger tumor size, poor differentiation and shorter survival of gastric cancer patients. Downregulation of BC032469 resulted in a significant inhibition of proliferation in vitro and in vivo. Mechanistically, BC032469 could directly bind to miR-1207-5p and effectively functioned as a sponge for miR-1207-5p to modulate the derepression of hTERT. Thus, BC032469 may function as a ceRNA to impair miR-1207-5p-dependent hTERT downregulation, suggesting that it may be clinically valuable as a poor prognostic biomarker of gastric cancer.

miR-1207-5p and miR-1266 suppress gastric cancer growth and invasion by targeting telomerase reverse transcriptase

hTERT is the catalytic subunit of the telomerase complex. Elevated expression of hTERT is associated with the expansion and metastasis of gastric tumor. In this study, we aimed to identify novel tumor suppressor miRNAs that restrain hTERT expression. We began our screen for hTERT-targeting miRNAs with a miRNA microarray. miRNA candidates were further filtered by bioinformatic analysis, general expression pattern in different cell lines, gain-of-function effects on hTERT protein and the potential of these effects to suppress hTERT 3′ untranslated region (3′UTR) luciferase activity. The clinical relevance of two miRNAs (miR-1207-5p and miR-1266) was evaluated by real-time RT-PCR. The effects of these miRNAs on cell growth, cell cycle and invasion of gastric cancer cells were measured with CCK-8, flow cytometry and transwell assays. Finally, the ability of these miRNAs to suppress the transplanted tumors was also investigated. Fourteen miRNAs were identified using a combination of bioinformatics and miRNA microarray analysis. Of these fourteen miRNAs, nine were expressed at significantly lower levels in hTERT-positive cell lines compared with hTERT-negative cell lines and five could downregulate hTERT protein expression. Only miR-1207-5p and miR-1266 interacted with the 3′ UTR of hTERT and the expression levels of these two miRNAs were significantly decreased in gastric cancer tissues. These two miRNAs also inhibited gastric tumor growth in vitro and in vivo. Altogether, miR-1207-5p and miR-1266 were determined to be hTERT suppressors in gastric cancer, and the delivery of these two miRNAs represents a novel therapeutic strategy for gastric cancer treatment.

Predictors of relapse in chronic hepatitis B after discontinuation of anti-viral therapy

BACKGROUND

Optimal duration of anti-viral therapy in chronic hepatitis B virus (HBV) infection remains unclear.

AIM

To investigate factors that could predict relapse after stopping anti-viral agents.

METHODS

Chronic hepatitis B patients who were treated with anti-viral agents (lamivudine, adefovir, entecavir) and have stopped the treatment were recruited. Anti-viral agents were stopped according to the recommendations of the Asian Pacific Association for the Study of the Liver. Virological relapse was defined as an increase in serum HBV DNA to >1000 copies/mL after discontinuation of treatment.

RESULTS

Eighty-four (69 treatment naïve and 15 lamivudine resistant) patients were eligible for this study. Thirty-seven patients developed virological relapse at 4.3 ± 2.9 (range 1-11) months after discontinuation of therapy. The 1-year cumulative probability of virological relapse was 42% and 47% in HBeAg (hepatitis B e antigen)-positive (n = 41) and HBeAg (hepatitis B e antigen)-negative (n = 43) patients, respectively. On multivariate analysis by Cox proportional hazard model, pre-existing lamivudine resistance, delayed suppression of HBV DNA to undetectable level during anti-viral therapy and to a higher HBsAg (hepatitis B surface antigen) level at the end of treatment were associated with virological relapse. Twelve of the 15 (80%) lamivudine resistant patients developed virological relapse. Among the 11 treatment naïve patients who had HBsAg ≤ 2 log IU/mL at the end of treatment, 1 (9%) of them had virological relapse.

CONCLUSIONS

Treatment cessation among lamivudine resistant patients is associated with high risk of virological relapse. Serum HBsAg level at the end of treatment and rate of HBV DNA suppression can provide supplementary information to guide the timing of stopping anti-viral drugs.

Procoagulant activity of erythrocytes and platelets through phosphatidylserine exposure and microparticles release in patients with nephrotic syndrome

Recent studies showed that an imbalance of prothrombotic and antithrombotic factors and impaired thrombolytic activity contribute to the thrombophilia of the nephrotic syndrome (NS). However, it is not clear whether blood cell injury and/or activation is involved in hypercoagulability in NS patients. Our objectives were to study the increase in microparticle (MP) release and phosphatidylserine (PS) exposure on the outer membrane of MP-origin cells in NS patients, and to evaluate their procoagulant activity (PCA). The subjects were patients with membranous nephropathy (MN), minimal change nephrotic syndrome (MCNS) and healthy controls. Analyses of MPs and PS exposure were performed using a flow cytometer. PCA was determined by clotting time and purified coagulation complex assays. We found that lactadherin+ MPs, which derived from red blood cells (RBC), platelet and endothelial cell, increased in NS patients. Moreover, PS exposure on RBCs and platelets in each NS group, especially in MN, are higher than that in controls. MP shedding and PS exposure of RBCs/platelets were highly procoagulant in NS patients. However, blockade of PS with lactadherin inhibited over 90% of PCA while an anti-tissue factor antibody had no significant inhibition effect. Our results demonstrate that the thrombophilic susceptibility of NS may be partly ascribed to MP release and PS exposure of RBCs, platelets and endothelial cells. Lactadherin is a sensitive probe for PS that has high anticoagulant activity.

Blood-brain barrier equilibration of codeine in rats studied with microdialysis

PURPOSE

The purpose of the study was to investigate the distribution of codeine across the blood-brain barrier (BBB) in rats by microdialysis (MD).

METHODS

Rats were administered intravenous infusion of codeine in doses of (1) 10 mg/kg, (2) 20 mg/kg for 10 min, and (3) an exponential infusion for 2 h aiming at a plasma concentration of 2500 ng/ml, in a crossover design (n = 6). Microdialysis was used to determine codeine unbound concentrations in blood and brain extracellular fluid (ECF). Total brain tissue and plasma concentrations were also determined. Nalorphine was used as a calibrator for measurement of in vivo recovery.

RESULTS

Relative recovery and retrodialysis loss of codeine and nalorphine were similar both in vitro and in vivo. Codeine was rapidly transported into the brain ECF with identical influx and efflux clearance across the BBB. The AUC ratios of brain to blood were 0.99 +/- 0.25 and 0.95 +/- 0.16 for Dose 1 and 2, respectively. The Css ratio of brain to blood was 1.06 +/- 0.12 for the exponential infusion. The half-lives were 25 +/- 4 min, 22 +/- 2 min in blood and 27 +/- 5 min, 25 +/- 5 min in brain for Dose 1 and Dose 2, respectively. Total brain tissue concentrations were 3.6 +/- 1.2-fold higher than the unbound concentrations in brain. Codeine was demethylated to morphine with an unbound AUCblood,morphine/AUCblood,codeine ratio of 7.7 +/- 5.1% in blood. No morphine was detected in brain MD, but total concentrations were possible to measure.

CONCLUSIONS

Codeine rapidly reached a distributional equilibrium with equal unbound concentrations in blood and brain. The brain transport of codeine did not show any dose-dependency.

A novel pharmacological approach to treating cardiac ischemia. Binary conjugates of A1 and A3 adenosine receptor agonists

Adenosine released during cardiac ischemia exerts a potent, protective effect in the heart via activation of A(1) or A(3) receptors. However, the interaction between the two cardioprotective adenosine receptors and the question of which receptor is the more important anti-ischemic receptor remain largely unexplored. The objective of this study was to test the hypothesis that activation of both receptors exerted a cardioprotective effect that was significantly greater than activation of either receptor individually. This was accomplished by using a novel design in which new binary conjugates of adenosine A(1) and A(3) receptor agonists were synthesized and tested in a novel cardiac myocyte model of adenosine-elicited cardioprotection. Binary drugs having mixed selectivity for both A(1) and A(3) receptors were created through the covalent linking of functionalized congeners of adenosine agonists, each being selective for either the A(1) or A(3) receptor subtype. MRS 1740 and MRS 1741, thiourea-linked, regioisomers of a binary conjugate, were highly potent and selective in radioligand binding assays for A(1) and A(3) receptors (K(i) values of 0.7-3.5 nm) versus A(2A) receptors. The myocyte models utilized cultured chick embryo cells, either ventricular cells expressing native adenosine A(1) and A(3) receptors, or engineered atrial cells, in which either human A(3) receptors alone or both human A(1) and A(3) receptors were expressed. The binary agonist MRS 1741 coactivated A(1) and A(3) receptors simultaneously, with full cardioprotection (EC(50) approximately 0.1 nm) dependent on expression of both receptors. Thus, co-activation of both adenosine A(1) and A(3) receptors by the binary A(1)/A(3) agonists represents a novel general cardioprotective approach for the treatment of myocardial ischemia.

Effects of a calcimimetic compound and naturally activating mutations on the human Ca2+ receptor and on Ca2+ receptor/metabotropic glutamate chimeric receptors

Naturally occurring mutations identified in subjects with autosomal dominant hypocalcemia (ADH) and the calcimimetic compound, R-568, have both been reported to increase Ca2+ sensitivity of the Ca2+ receptor (CaR). To gain insight into their mechanism of action, we studied interactions between four different ADH mutations located in the amino-terminal extracellular domain (ECD) and R-568. We found that R-568 increased the sensitivity of three of the ADH mutant receptors, but the Leu125Pro mutant appeared to be maximally left-shifted in that neither R-568 addition nor combining other ADH mutations with Leu125Pro gave increases in sensitivity comparable to those seen with the three other ADH mutations studied. We also made use of truncation and deletion mutants of the CaR and CaR/metabotropic glutamate receptor type 1 (mGluR1) chimeras to study both the site of action of R-568 and the effect of the Leu125Pro activating mutation. R-568 was effective in receptor constructs containing the seven transmembrane domain (7TM) of the CaR, but not in those containing the mGluR1 7TM. R-568, moreover, imparted Ca2+ responsiveness to CaR constructs lacking all or part of the CaR ECD. The Leu125Pro mutation in contrast conferred no or minimal increase in Ca2+ responsiveness to CaR constructs lacking part of the CaR ECD but showed a striking increase in basal activity in the context of chimeras containing an mGluR1 7TM. Our results localize the site of action of NPS-568 specifically to the CaR 7TM. Our results with the Leu125Pro mutant, furthermore, suggest that the mGluR1 7TM domain may be more permissive for activation than the 7TM domain of the CaR.

Isoflurane enhances the malignant potential of glioblastoma stem cells by promoting their viability, mobility in vitro and migratory capacity in vivo

BACKGROUND

Isoflurane is one of the most common general anaesthetics used during surgical procedures, including tumour resection. However, the effects of isoflurane on the viability and migration capacity of cancer cells, specifically in the context of brain cancer cells, remain unclear. Therefore, the aim of this study was to evaluate the influence that isoflurane has on the function of glioblastoma stem cells (GCSs) in regards to cell proliferation, survival and migration.

METHOD

U251-GSCs were exposed to isoflurane at clinically relevant concentrations and incubation times. The effects on proliferation, survival and migration capacities of the cells were evaluated in vitro. The potential risk was assessed in mice by intracranial injection of U251-GSCs pretreated with isoflurane. Furthermore, the average tumour volume and migration distance of U251-GSCs from the tumour centre were calculated.

RESULTS

Exposure of U251-GSCs to 1.2% isoflurane for 6 h resulted in increased proliferation (P<0.05) and decreased apoptosis rate (P<0.05) when compared with the control group. In addition, isoflurane exposure caused increased migration capacity in vitro (P<0.05) and the distance migrated was increased in vivo (P<0.05).

CONCLUSION

Clinically relevant concentrations and incubation times of isoflurane could promote the viability and mobility of U251-GSCs, suggesting this general anaesthetic may have detrimental effects in glioblastoma by facilitating its growth and migration.

Glucocorticoids coordinately regulate type I collagen pro alpha 1 promoter activity through both the glucocorticoid and transforming growth factor beta response elements: a novel mechanism of glucocorticoid regulation of eukaryotic genes

Glucocorticoids have previously have shown to decrease Type I collagen synthesis in vivo and in fibroblast cell culture. Several studies have demonstrated that glucocorticoids decrease Type I procollagen gene expression. These latter studies have included uridine incorporation into pro alpha 1 (I) and pro alpha 2 (I) mRNAs and nuclear run-off experiments. Using the ColCat 3.6 plasmid, which contains part of the 5' flanking region of the pro alpha 1 (I) collagen gene and the reporter gene, chloramphenicol acetyltransferase, the present studies demonstrate by stable transfection of fetal rat skin fibroblasts that dexamethasone down regulates the promoter activity of the pro alpha 1 (I) collagen gene. The glucocorticoid-mediated down-regulation of procollagen gene expression was demonstrated using the ColCat 3.6, 2.4, 1.7, or 0.9 plasmid. In addition, competitive oligonucleotide transfection experiments and site specific mutation of the glucocorticoid response element (GRE) in the whole ColCat 3.6 plasmid did not eliminate the effect. The possibility existed that another cis-element in the 5' flanking region of the pro alpha 1 (I) collagen gene was also required for the collagen glucocorticoid-mediated down-regulation of procollagen gene expression, since TGF-beta has been shown to stimulate in a decrease of transforming growth factor-beta (TGF-beta) secretion into the media. Gel mobility studies demonstrated that glucocorticoid treatment of rat skin fibroblasts decreased glucocorticoid receptor binding to the GRE and TGF-beta activator protein to the TGF-beta element which were brought back to control values by coordinate exogenous TGF-beta treatment. Thus the interaction of these TGF-beta molecules with cellular membrane receptors and subsequent transduction is dramatically decreased resulting in less signals to regulate collagen gene expression. These data indicate that glucocorticoids coordinately regulate procollagen gene expression through both the GRE and TGF-beta elements. Depression of procollagen gene expression by glucocorticoids through the TGF-beta element is mediated by decreased TGF-beta secretion, possibly involving a secondary effect on regulatory protein(s) encoded by noncollagenous protein gene(s). The present studies provide the basis for a novel mechanism of glucocorticoid-mediator regulation of eukaryotic genes containing the TGF-beta element.

Whole cell recordings of intrinsic properties and sound-evoked responses from the inferior colliculus

Response features of inferior colliculus (IC) neurons to both current injections and tone bursts were studied with in vivo whole cell recordings in awake Mexican free-tailed bats. Of 160 cells recorded, 95% displayed one of three general types of discharge patterns in response to the injection of positive current: 1) sustained discharges; 2) adapting discharges; and 3) onset-bursting discharges. Sustained neurons were the most common type (N=78), followed by onset-bursting (N=57). The least common type was adapting (N=17). In 90 neurons the profiles of synaptic and discharge activity evoked by tones of different frequencies at 50 dB SPL were recorded. Three major tone-evoked response profiles were obtained; 1) neurons dominated by excitation (N=32) in which tones evoked excitatory post-synaptic potentials (EPSPs) or EPSPs with discharges over a range of frequencies with little or no evidence of inhibitory post-synaptic potentials (IPSPs) evoked by frequencies that flanked the excitation; 2) neurons that had an excitatory frequency region in which discharges were evoked that was flanked by frequencies that evoked predominantly IPSPs (N=26); 3) neurons in which all frequencies evoked IPSPs with little or no depolarizations (N=32). The question we asked is whether IC cells that express a particular profile of PSPs and discharges to acoustic stimulation also have the same current-evoked response profile. We show that, with one exception, the intrinsic features of an IC neuron are not correlated with the pattern of its synaptic innervation; the two features are unrelated in the majority of IC cells. The exception is a subtype of inhibitory dominated cell where most frequencies evoked IPSPs to both the onset and to the offset of the tone bursts. In those cells injected current steps always evoked an onset-bursting response.

Orthodontic force stimulates eNOS and iNOS in rat osteocytes

Mechanosensitive osteocytes are essential for bone remodeling. Nitric oxide, an important regulator of bone remodeling, is produced by osteocytes through the activity of constitutive endothelial nitric oxide synthase (eNOS) or inducible nitric oxide synthase (iNOS). We hypothesized that these enzymes regulate the tissue response to orthodontic force, and therefore we investigated eNOS and iNOS expression in osteocytes during orthodontic force application. The upper rat molars were moved mesially by NiTi coil springs (10 cN, 120 hrs) in a split-mouth design. Immunohistochemical staining revealed that, in the tension area, eNOS-positive osteocytes increased from 24 hrs on, while iNOS-positive osteocytes remained largely constant. In the compression area, iNOS-positive osteocytes increased after 6 hrs, while eNOS- positive osteocytes increased after 24 hrs. This suggests that eNOS mediates bone formation in the tension area, while iNOS mediates inflammation-induced bone resorption in the compression area. Both eNOS and iNOS seem to be important regulators of bone remodeling during orthodontic force application.

The cell cycle control element of histone H4 gene transcription is maximally responsive to interferon regulatory factor pairs IRF-1/IRF-3 and IRF-1/IRF-7

Interferon regulatory factors (IRFs) are transcriptional mediators of interferon-responsive signaling pathways that are involved in antiviral defense, immune response, and cell growth regulation. To investigate the role of IRF proteins in the regulation of histone H4 gene transcription, we compared the transcriptional contributions of IRF-1, IRF-2, IRF-3, and IRF-7 using transient transfection assays with H4 promoter/luciferase (Luc) reporter genes. These IRF proteins up-regulate reporter gene expression but IRF-1, IRF-3, and IRF-7 are more potent activators of the H4 promoter than IRF-2. Forced expression of different IRF combinations reveals that IRF-2 reduces IRF-1 or IRF-3 dependent activation, but does not affect IRF-7 function. Thus, IRF-2 may have a dual function in histone H4 gene transcription by acting as a weak activator at low dosage and a competitive inhibitor of other strongly activating IRFs at high levels. IRF-1/IRF-3 and IRF-1/IRF-7 pairs each mediate the highest levels of site II-dependent promoter activity and can up-regulate transcription by 120-150-fold. We also find that interferon gamma up-regulates IRF-1 and site II-dependent promoter activity. This up-regulation is not observed when the IRF site is mutated or if cells are preloaded with IRF-1. Our results indicate that IRF-1, IRF-2, IRF-3, and IRF-7 can all regulate histone H4 gene expression. The pairwise utilization of distinct IRF factors provides a flexible transcriptional mechanism for integration of diverse growth-related signaling pathways.

Advanced malignant pleural or peritoneal effusion in patients treated with recombinant adenovirus p53 injection plus cisplatin

The aim of this study was to evaluate the efficacy of recombinant adenovirus p53 agent (rAd-p53) injection combined with cisplatin (CDDP) for the treatment of malignant pleural or peritoneal effusion. After puncture drainage, patients in the treatment group (n = 27) received intracavitary administration of rAd-p53 (2 x 10(12) virus particles) once a week for 4 weeks. At 48 h after each rAd-p53 injection, patients were given intracavitary administration of cisplatin 60 mg/m(2). This administration procedure continued once a week for 4 weeks. The control group (n = 21) received the same intracavitary therapy as the treatment group but without rAd-p53 therapy. Efficacy was evaluated by clinical observations, computed tomography, tumour markers, Karnofsky score and short-term follow-up. The total effective rates for the treatment group (63.0%) were significantly higher than for the control group (42.9%), suggesting that the treatment group benefited over the control group. In conclusion, rAd-p53 therapy is a safe and effective treatment for advanced malignant pleural or peritoneal effusion.

Rat Parathyroid Hormone 1 − 34 Signals through the MEK/ERK Pathway to Induce Cardiac Hypertrophy

This study aimed to characterize the role of the mitogen-activated protein kinase (MAPK) kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway in cardiac hypertrophy induced by parathyroid hormone (PTH). Various concentrations of rat PTH1–34 were used to induce hypertrophy in neonatal rat ventricular cardiomyocytes, and the effects were compared with control cells and those treated with PD98059, a selective inhibitor of MEK1. Hypertrophy was assessed in terms of cell diameter, atrial natriuretic peptide (ANP) mRNA expression and protein synthesis; the MEK/ERK pathway was assessed by measuring levels of phosphorylated ERK1/2. Treatment with PTH1–34 at 100 nM for 24 h effectively induced cardiac hypertrophy (increased cell diameter, protein synthesis and ANP mRNA expression) and also increased levels of phosphorylated ERK1/2 compared with normal control cells. Treatment with PTH1–34 plus PD98059 significantly attenuated these changes. These results demonstrate that inhibition of the MEK/ERK pathway blocks PTH1–34-induced cardiac hypertrophy, suggesting that PTH1–34 might signal through the MAPK pathway to induce hypertrophy in cardiomyocytes.

Highly toxic and broad-spectrum insecticidal Bacillus thuringiensis engineered by using the transposon Tn917 and protoplast fusion

The chromosome of the Bacillus thuringiensis strain S184 that was toxic against the third instar larvae of Spodoptera litura with the LC(50) of 9.74 microg/ml was successfully integrated into two genes of cyt1Aa and cry11Aa using the transposon Tn917, yielding the primary engineered strain TnX. The strain TnX was highly toxic to the third instar larvae of Culex pipiens fatigans with the LC(50) of 5.12 ng/ml which was 1.82-fold higher than that of B. thuringiensis subsp. israelensis, but lowly toxic to lepidopterous larvae. By the protoplast fusion of the strain TnX and the strain S184-Tet(r) (resistance to tetracycline), the target engineered strain TnY was obtained. Against the third instar larvae of S. litura, the strain TnY LC(50) was of 4.68 micro g/ml and increased by 2.08-fold in comparison with the parent strain S184. Against the third instar larvae of C. pipiens fatigans, the strain TnY LC(50) was of 103.20 ng/ml. The two target genes of cyt1Aa and cry11Aa integrated into the chromosome were extremely stable and had little possibility of a second transposition. It was unclear whether some factors existing in the parent strain, S184, contributed to the high toxicity of the strains TnX and TnY.

Phase I and pharmacokinetic study of irinotecan in combination with R115777, a farnesyl protein transferase inhibitor

The aims of this study were to determine the maximum-tolerated dose (MTD), toxicity profile, and pharmacokinetics of irinotecan given with oral R115777 (tipifarnib), a farnesyl protein transferase inhibitor. Patients were treated with escalating doses of irinotecan with interval-modulated dosing of R115777 (continuously or on days 1–14, and repeated every 21 days). In total, 35 patients were entered onto the trial for a median duration of treatment of 43 days (range, 5–224 days). Neutropenia and thrombocytopenia were the dose-limiting toxicities; other side effects were mostly mild. The MTD was established at R115777 300 mg b.i.d. for 14 consecutive days with irinotecan 350 mg m⁻² given every 3 weeks starting on day 1. Three patients had a partial response and 14 had stable disease. In the continuous schedule, the area under the curves of irinotecan and its active metabolite SN-38 were 20.0% (P=0.004) and 38.0% (P<0.001) increased by R115777, respectively. Intermittent dosing of R115777 at a dose of 300 mg b.i.d. for 14 days every 3 weeks is the recommended dose of R115777 in combination with the recommended single-agent irinotecan dose of 350 mg m⁻².

Generation of the enol of methyl mandelate by flash photolysis of methyl phenyldiazoacetate in aqueous solution and study of rates of ketonization of this enol in that medium

Flash photolysis of methyl phenyldiazoacetate in aqueous solution produced phenylcarbomethoxycarbene, whose hydration generated a short-lived transient species that was identified as the enol isomer of methyl mandelate. This assignment is supported by the shape of the rate profile for decay of the enol transient, through ketonization to its carbonyl isomer, as well as by solvent isotope effects and the form of acid-base catalysis of the ketonization reaction. Comparison of the present results with previously published information on the enol of mandelic acid shows some interesting and readily understandable similarities and differences.