Circ_0000190 suppresses gastric cancer progression potentially via inhibiting miR-1252/PAK3 pathway.

BACKGROUND: Gastric cancer is a serious malignant tumor associated with aberrant circular RNAs (circRNAs) expression. In this study, we aim to investigate the role and the underlying mechanism of circ_0000190, a circRNA in gastric cancer. METHODS: Circ_0000190 expression in vivo was examined in gastric cancer and adjacent normal tissues by RT-PCR. Circ_0000190 expression in gastric cancer cell lines was detected by FISH and RT-PCR. The role of the circRNA in gastric cancer cells was assessed by the analysis of cell viability, apoptosis, proliferation, cell cycle and migration. The potential effector of circ_0000190 was predicted by computational screen and validated by luciferase reporter assay. Furthermore, Mice model of human gastric cancer was established to observe the underlying mechanisms of circ_0000190. RESULTS: Circ_0000190 was down-regulated in gastric cancer tissues and cells, with a major location in cytoplasm. Circ_0000190 inhibited gastric cancer cell viability, proliferation and migration, and induced apoptosis and cell cycle arrest by regulating the expression of capase-3, p27 and cyclin D. In addition, the circRNA was validated as a sponge of miR-1252, which directly targeted PAK3. The effects of circ_0000190 on the cellular processes were blocked by miR-1252 mimics, which could be rescued after further overexpression of PAK3. CONCLUSIONS: Circ_0000190 suppresses gastric cancer progression potentially via inhibiting miR-1252/PAK3 pathway, employing circ_0000190 might be a promising therapeutic strategy for the treatment of gastric cancer.

BIX-01294 enhanced chemotherapy effect in gastric cancer by inducing GSDME-mediated pyroptosis.

Adjuvant chemotherapy in combination with surgery is expected to be a curative strategy for gastric cancer. However, drug resistance remains an obstacle in effective chemotherapy. Therefore, understanding the potential mechanisms of chemotherapy induced gastric cancer cell death is of great importance. We demonstrated that BIX-01294 (BIX) at low concentration could induce autophagic flux by converting LC3B-I to LC3B-II and directly activate autophagy associated cell death in gastric cancer cell lines at high concentration. BIX at low concentration could help obtain sensitivity of gastric cancer cells to chemotherapy with significantly reduced cell viability. Interestingly, BIX combined Cis (BIX + Cis) treated SGC-7901 cells display pyroptosis related cell death with large bubbles blown around the membrane, significantly decreased cell viability, elevated lactate dehydrogenase release and increased percentage of propidium iodide and Annexin-V double positive cells. Furthermore, the cleavage of gasdermin E (GSDME) and caspase-3 but not GSDMD was detected by immunoblotting and the knockout of GSDME switched pyroptosis into apoptosis in the BIX + Cis combined treated group. Furthermore, the deficiency of Beclin-1 to inhibit BIX induced autophagic flux completely blocked BIX + Cis combined treated induced cell pyroptosis related cell death. Additionally, BIX + Cis in vivo treatment could inhibit tumor growth, which could be reversed by the deficiency of Beclin-1 and be delayed by the deficiency of GSDME. In conclusion, our data was the first to reveal that BIX enhanced the anticancer chemotherapy effect by induced GSDME-mediated pyroptosis through the activation of autophagic flux in gastric cancer cells.

[Morphological Characteristics and Molecular Identification of Trichuris sp. from Giraffe].

Objective: To investigate the morphological characteristics of Trichuris sp. from giraffe in Hefei wild zoo and identify its species using molecular techniques. Methods: Morphological characteristics of Trichuris collected from giraffe were analyzed. The internal transcribed spacer 1（ITS-1） was amplified by PCR and the PCR product was sequenced. The resulting sequence was homology analysis in GenBank and its heredity evolution tree was constructed by MEGA 4.0 software. Results: The male worms had a body length of 35.89-58.56 mm, an esophagus to body length ration of 0.29-0.40, and a spicule length of 1.96-3.89 mm. The thick and thin proportions of body were 7.02-23.45 mm and 28.05-40.05 mm respectively. These data showed different degrees of variation with previous reports. The PCR resulted in a product of 491 bp, comprising part of 18S rRNA and full length ITS-1. Sequence alignment showed that the identified Trichuris was most homologous（98.6%） with T. bos taurus HE608848, T. capreolus JX218218, and T. japanese AB367795, but it was only 46.0% homologous with T. discolor AB367794. In the heredity evolution tree, it was not located on the same branch as T. discolor, T. ovis and T. bos taurus. Conclusions: The Trichuris sp. collected from giraffe is different from previous reports in morphology and ITS-1 sequence. Further research is needed to determine if it is a new species.

Molecular characterization of a novel reovirus isolated from Pekin ducklings in China.

The complete genome sequence of a novel duck orthoreovirus, designated DRV strain TH11(DRV-TH11), was determined and characterized. The DRV-TH11 genome is comprised of 23,417 bp and its genome organization is more similar to that of avian orthoreoviruses (ARVs) of chicken origin than other reoviruses. The results of comparative sequence analysis and dendrograms based on the µB- and σC-encoding genes indicated that TH11 may be derived from the reassortment of ARVs and classic Muscovy duck reovirus (MDRV). A possible recombinant event was identified using the SimPlot program, and it occurred in the M2 segment. The results indicated that reassortment and mutation play a role in the evolution of duck reovirus.

Expression of protease-activated receptor-2 in human gastric stromal tumor and its clinicopathological significance.

BACKGROUND/AIMS: To explore the expression of protein-activated receptor-2 (PAR-2) in human gastric stromal tumor and its clinicopathological significance. METHODOLOGY: The expression of PAR-2 was detected with immunohistochemisty, RT-PCR and Western blot in tumor tissue, peritumoral tissue and gastric normal tissue from 72 patients with gastric stromal tumor. RESULTS: PAR-2 expression was significantly higher in peritumoral tissue (p < 0.05) and tumor tissue (p < 0.01) than in gastric normal tissue, and significantly higher in tumor tissue than in peritumoral tissue (p < 0.01). With the increase in NIH grade, PAR-2 expression was elevated in tumor tissues. PAR-2 expression was strongly associated with mucosal invasion. CONCLUSIONS: PAR-2 expression is significantly higher in gastric stromal tumor tissue than in peritumoral tissue and gastric normal tissue. The high expression of PAR-2 may be associated with the invasion and metastasis of gastric stromal tumor.

Thymus exosomes-like particles induce regulatory T cells.

Exosomes released from different types of cells have been proposed to contribute to intercellular communication. We report that thymic exosome-like particles (ELPs) released from cells of the thymus can induce the development of Foxp3(+) regulatory T (Treg) cells in the lung and liver. Thymic ELPs also induce the conversion of thymic CD4(+)CD25(-) T cells into Tregs. Tregs induced by thymic ELPs suppress the proliferation of CD4(+)CD25(-) T cells in vitro and in vivo. We further show that neutralization of TGF-beta in ELPs partially reverses thymic ELP-mediated induction of CD4(+)Foxp3(+) T cells in the lung and liver. This study demonstrates that thymic ELPs participate in the induction of Foxp3(+) Tregs. Also, TGF-beta of thymic ELPs might be required for the generation of Tregs in the peripheral tissues.

Induction of myeloid-derived suppressor cells by tumor exosomes.

Myeloid-derived suppressor cells (MDSCs) promote tumor progression. The mechanisms of MDSC development during tumor growth remain unknown. Tumor exosomes (T-exosomes) have been implicated to play a role in immune regulation, however the role of exosomes in the induction of MDSCs is unclear. Our previous work demonstrated that exosomes isolated from tumor cells are taken up by bone marrow myeloid cells. Here, we extend those findings showing that exosomes isolated from T-exosomes switch the differentiation pathway of these myeloid cells to the MDSC pathway (CD11b(+)Gr-1(+)). The resulting cells exhibit MDSC phenotypic and functional characteristics including promotion of tumor growth. Furthermore, we demonstrated that in vivo MDSC mediated promotion of tumor progression is dependent on T-exosome prostaglandin E2 (PGE2) and TGF-beta molecules. T-exosomes can induce the accumulation of MDSCs expressing Cox2, IL-6, VEGF, and arginase-1. Antibodies against exosomal PGE2 and TGF-beta block the activity of these exosomes on MDSC induction and therefore attenuate MDSC-mediated tumor-promoting ability. Exosomal PGE2 and TGF-beta are enriched in T-exosomes when compared with exosomes isolated from the supernatants of cultured tumor cells (C-exosomes). The tumor microenvironment has an effect on the potency of T-exosome mediated induction of MDSCs by regulating the sorting and the amount of exosomal PGE2 and TGF-beta available. Together, these findings lend themselves to developing specific targetable therapeutic strategies to reduce or eliminate MDSC-induced immunosuppression and hence enhance host antitumor immunotherapy efficacy.

Reactivation of microRNA-506 inhibits gastric carcinoma cell metastasis through ZEB2.

MicroRNAs (miRNAs) are frequently dysregulated in a variety of human cancers, including gastric carcinoma. To improve our understanding of the role of miRNAs in gastric carcinoma and potential identify novel biomarkers or therapeutic agents, we performed microarray analysis to identify differentially expressed miRNAs in gastric carcinoma, compared with paired non-cancerous gastric tissues. We identified significantly differentially expressed miRNAs in gastric carcinoma tissues, including miR-506. We validated the microarray results by quantitative reverse transcription polymerase chain reaction in 26 specimens and confirmed significant downregulation of miR-506 in gastric carcinoma. Bioinformatics analysis predicted ZEB2 (zinc finger E-box-binding homeobox 2) as a potential target of miR-506. MiR-506 levels and ZEB2 levels were inversely correlated in gastric carcinoma, and low miR-506 levels in gastric carcinoma were associated with poor prognosis. Overexpression of miR-506 in gastric carcinoma cells significantly inhibited cell migration and invasion, while depletion of miR-506 in gastric carcinoma cells significantly increased cell migration and invasion. Transplantation of miR-506-overexpressing gastric carcinoma cells developed significantly smaller tumor, compared to the control. Thus, our results suggest that miR-506 may function as a tumor suppressor and targets and inhibits ZEB2 in gastric carcinoma.

IP3R and RyR calcium channels are involved in neonatal rat cardiac myocyte hypertrophy induced by tumor necrosis factor-α.

To investigate which calcium channels are involved in cardiac myocyte hypertrophy induced by TNF-α, cultured cardiomyocytes were treated with 100 µg/L TNF-α. In addition, three different calcium channel blockers (2-APB, ryanodine and nifedipine) were used, and the effects of each calcium channel blocker on cardiac hypertrophy induced by TNF-α were carefully observed. Measurements included cytosolic calcium transients ([Ca2+]i), the level of intracellular calcium in individual cells, cell protein content, cell protein synthesis and cell volume. We found that the IP3R inhibitor (2-APB) and RyR inhibitor (ryanodine) both had significant suppressive effects on the level of [Ca2+]i, calcium concentration, cell protein content, cell protein synthesis and cell volume of cardiomyocytes treated with TNF-α (P<0.01). Moreover, their combined effects were significantly enhanced compared with their single effects (P<0.01). However, the inhibitor of the L type Ca2+ channel nifedipine exhibited no significant suppressive effects on the increase in [Ca2+]i, calcium concentration, cell protein content, cell protein synthesis and cell volume of cardiomyocytes induced by TNF-α (P>0.05). Our results suggest that TNF-α probably induces cardiac myocyte hypertrophy by activating IP3R and RyR calcium channels, which control the release of calcium ions from the sarcoplasmic reticulum (SR) in cardiomyocytes. On the other hand, extracellular calcium influx, which is mainly regulated by the L type Ca2+ channel, may not be involved in cardiac myocyte hypertrophy induced by TNF-α.

Protective Effects of Emodin-Induced Neutrophil Apoptosis via the Ca2+-Caspase 12 Pathway against SIRS in Rats with Severe Acute Pancreatitis.

Severe acute pancreatitis (SAP) results in high mortality. This is partly because of early multiple organ dysfunction syndromes that are usually caused by systemic inflammatory response syndrome (SIRS). Many studies have reported the beneficial effects of emodin against SAP with SIRS. However, the exact mechanism underlying the effect of emodin remains unclear. This study was designed to explore the protective effects and underlying mechanisms of emodin against SIRS in rats with SAP. In the present study, cytosolic Ca2+ levels, calpain 1 activity, and the expression levels of the active fragments of caspases 12 and 3 decreased in neutrophils from rats with SAP and increased after treatment with emodin. Delayed neutrophil apoptosis occurred in rats with SAP and emodin was able to reverse this delayed apoptosis and inhibit SIRS. The effect of emodin on calpain 1 activity, the expression levels of the active fragments of caspases 12 and 3, neutrophil apoptosis, and SIRS scores were attenuated by PD150606 (an inhibitor of calpain). These results suggest that emodin inhibits SIRS in rats with SAP by inducing circulating neutrophil apoptosis via the Ca2+-calpain 1-caspase 12-caspase 3 signaling pathway.

Protective immune responses in ducklings induced by a suicidal DNA vaccine of the sigma C gene of novel duck reovirus.

A suicidal DNA vaccine based on a Semliki Forest virus (SFV) replicon was evaluated for the development of a vaccine against novel duck reovirus (NDRV). The sigma C gene of NDRV was cloned and inserted into pSCA1, an SFV DNA-based replicon vector. After transfected into BHK-21 cells, the antigenicity of the sigma C protein was confirmed using an indirect immunofluorescence and Western blot assay. Immunogenicity was studied in ducklings. The results showed that NDRV-specific antibodies, neutralizing antibodies, IFN-γ and IL-4 were well induced in ducklings. Furthermore, all of the ducklings were protected against challenge with wild-type NDRV.

Expression of tissue factor pathway inhibitor-2 in gastric stromal tumor and its clinical significance.

The aim of this study was to explore the expression of tissue factor pathway inhibitor-2 (TFPI-2) in gastric stromal tissue and its clinical significance. TFPI-2 expression was detected by immunohistochemical analysis, RT-PCR and western blotting in tumor, peritumoral and gastric normal tissues from 72 patients with gastric stromal tumors. The level of TFPI-2 expression was observed to be significantly higher in gastric normal tissue than in peritumoral tissue, and was significantly higher in peritumoral tissue than in tumor tissue (P<0.01). As the NIH grade increased, the level of TFPI-2 expression decreased (P<0.01). A low expression level of TFPI-2 was closely associated with invasion and metastasis of gastric stromal tumors. In conclusion, the level of TFPI-2 expression was higher in gastric normal tissue than in gastric stromal tumors. Low expression levels of TFPI-2 may be associated with invasion and metastasis of gastric stromal tumors.

[Calcineurin contributed to tumor necrosis factor alpha-induced cardiomyocyte hypertrophy in rats].

OBJECTIVE: To investigate whether calcineurin (CaN) contribute to tumor necrosis factor alpha (TNF-alpha)-induced cardiomyocyte hypertrophy. METHODS: The protein content was assayed with lowry's method. The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with [3H]-leucine incorporation method. [Ca2+]i transient was measured by Till image system by cell-loading Fura-2/AM. The expression of CaN was determined by Western blot. RESULTS: (1) (CsA (0.2 micromol/L), a selective CaN inhibitor, significantly suppressed the increase of protein content, [3H]-leucine incorporation and cell size induced by TNF-alpha. (2) CsA (0.2 micromol/L) significantly suppressed the elevation of the amplitude of the spontaneous Ca2+ transients induced by TNF-alpha in cultured ventricular myocytes from the neonatal rat. (3) TNF-alpha significantly increased the expression of CaN. CONCLUSION: Ca(2+) -CaN signaling pathway are involved in cardiomyocyte hypertrophy induced by TNF-alpha in rats.

The role of Ca2+/calmodulin-dependent protein kinase II and calcineurin in TNF-α-induced myocardial hypertrophy.

We investigated whether Ca2+/calmodulin-dependent kinase II (CaMKII) and calcineurin (CaN) are involved in myocardial hypertrophy induced by tumor necrosis factor α (TNF-α). The cardiomyocytes of neonatal Wistar rats (1-2 days old) were cultured and stimulated by TNF-α (100 µg/L), and Ca2+ signal transduction was blocked by several antagonists, including BAPTA (4 µM), KN-93 (0.2 µM) and cyclosporin A (CsA, 0.2 µM). Protein content, protein synthesis, cardiomyocyte volumes, [Ca2+]i transients, CaMKIIδB and CaN were evaluated by the Lowry method, [³H]-leucine incorporation, a computerized image analysis system, a Till imaging system, and Western blot analysis, respectively. TNF-α induced a significant increase in protein content in a dose-dependent manner from 10 µg/L (53.56 µg protein/well) to 100 µg/L (72.18 µg protein/well), and in a time-dependent manner from 12 h (37.42 µg protein/well) to 72 h (42.81 µg protein/well). TNF-α (100 µg/L) significantly increased the amplitude of spontaneous [Ca2+]i transients, the total protein content, cell size, and [³H]-leucine incorporation in cultured cardiomyocytes, which was abolished by 4 µM BAPTA, an intracellular Ca2+ chelator. The increases in protein content, cell size and [³H]-leucine incorporation were abolished by 0.2 µM KN-93 or 0.2 µM CsA. TNF-α increased the expression of CaMKIIδB by 35.21% and that of CaN by 22.22% compared to control. These effects were abolished by 4 µM BAPTA, which itself had no effect. These results suggest that TNF-α induces increases in [Ca2+]i, CaMKIIδB and CaN and promotes cardiac hypertrophy. Therefore, we hypothesize that the Ca2+/CaMKII- and CaN-dependent signaling pathways are involved in myocardial hypertrophy induced by TNF-α.

[Comparing effects of U50488H, prazosin and/or propranolol on cardiac hypertrophy induced by NE in rat].

OBJECTIVE: To demonstrate the inhibitory effect of kappa-opioid receptor activation by U50488H on hypertrophy induced by NE in cultured neonatal rat cardiac myocytes and compare its effect with that of prazosin and propranolol. METHODS: The cellular proliferation was determined with crystal violet staining. The protein content was assayed with Lowry's method. The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with [3H]-lencine incorporation method. RESULTS: (1) NE significantly induced the increase of protein content, [3H]-leucine incorporation and cell size without a concomitant increase in cell number in low serum medium. OThese responses were partially suppressed by prazosin or propranolol alone and completely abolished by both in combination. U50488H significantly inhibited the NE-induced increase of protein content, [3H]-leucine incorporation and cell size. The inhibitory effects of U50488H on NE-induced cardiac hypertrophy were greater than either prazosin or propranolol, but comparable to combination of both. CONCLUSION: NE, acting via both alpha1- and beta-adrenergic pathway, stimulates myocyte hypertrophy. Stimulating kappa-opioid receptor significantly inhibits NE-induced cardiac hypertrophy, which may be related with alpha1- and beta1-adrenergic pathway.

[Ca2+ is involved in tumor necrosis factor-alpha induced cardiomyocyte hypertrophy through PI3-kinase pathway in rats].

OBJECTIVE: To investigate whether Ca2+ contribute to cardiomyocyte hypertrophy induced by tumor necrosis factor-alpha (TNF-alpha) through PI3-kinase pathway. METHODS: The protein content was assayed with Lowry's method. The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with [3H]-leucine incorporation method. [Ca2+]i transient was measured by Till image system by cell-loading Fura-2/AM. RESULTS: (1) TNF-alpha significantly induced the increase of protein content, [3H]-leucine incorporation and cell size. These responses were significantly suppressed by LY294002, a selective PI3-kinase inhibitor. Verapamil, L-type calcium channels antagonist, slightly attenuated TNF-alpha-induced these responses. (2) TNF-alpha increased the amplitude of the spontaneous Ca2+ transients in cultured ventricular myocytes from the neonatal rat; PI3-kinase inhibitor LY294002 could suppress the elevation induced by TNF-alpha, but calcium antagonist verapamil took the minor effects of TNF-alpha on [Ca2+]i metabolism. CONCLUSION: Increasing the intercellular free Ca2+ level may play an essential role in TNF-alpha-induced cardiomyocyte hypertrophy through PI3-kinase pathway in rats, while L-type calcium channel takes the minor effects on it.

The role of Ca2+/calmodulin-dependent protein kinase II and calcineurin in TNF-α-induced myocardial hypertrophy

We investigated whether Ca2+/calmodulin-dependent kinase II (CaMKII) and calcineurin (CaN) are involved in myocardial hypertrophy induced by tumor necrosis factor α (TNF-α). The cardiomyocytes of neonatal Wistar rats (1-2 days old) were cultured and stimulated by TNF-α (100 μg/L), and Ca2+ signal transduction was blocked by several antagonists, including BAPTA (4 µM), KN-93 (0.2 µM) and cyclosporin A (CsA, 0.2 µM). Protein content, protein synthesis, cardiomyocyte volumes, [Ca2+]i transients, CaMKIIδB and CaN were evaluated by the Lowry method, [³H]-leucine incorporation, a computerized image analysis system, a Till imaging system, and Western blot analysis, respectively. TNF-α induced a significant increase in protein content in a dose-dependent manner from 10 µg/L (53.56 µg protein/well) to 100 μg/L (72.18 µg protein/well), and in a time-dependent manner from 12 h (37.42 µg protein/well) to 72 h (42.81 µg protein/well). TNF-α (100 μg/L) significantly increased the amplitude of spontaneous [Ca2+]i transients, the total protein content, cell size, and [³H]-leucine incorporation in cultured cardiomyocytes, which was abolished by 4 µM BAPTA, an intracellular Ca2+ chelator. The increases in protein content, cell size and [³H]-leucine incorporation were abolished by 0.2 µM KN-93 or 0.2 µM CsA. TNF-α increased the expression of CaMKIIδB by 35.21% and that of CaN by 22.22% compared to control. These effects were abolished by 4 µM BAPTA, which itself had no effect. These results suggest that TNF-α induces increases in [Ca2+]i, CaMKIIδB and CaN and promotes cardiac hypertrophy. Therefore, we hypothesize that the Ca2+/CaMKII- and CaN-dependent signaling pathways are involved in myocardial hypertrophy induced by TNF-α.