Proteases for cell suicide: functions and regulation of caspases

Identification of a CqCaspase gene with antiviral activity from red claw crayfish Cherax quadricarinatus

Caspase, an aspartate specific proteinase mediating apoptosis, plays a key role in immune response. In our previous study, the expression of a caspase gene was up-regulated in a transcriptome library from the haematopoietic tissue (Hpt) cells of red claw crayfish Cherax quadricarinatus post white spot syndrome virus (WSSV) infection. To further reveal the effect of caspase on WSSV infection, we cloned this caspase gene (denominated as CqCaspase) with an open reading frame of 1062 bp, which encoded 353 amino acids with a caspase domain (CASc) containing a p20 subunit and a p10 subunit. Tissue distribution analysis indicated that the mRNA transcript of CqCaspase was widely expressed in all tested tissues with the highest expression in Hpt, while the lowest expression in muscle. To further explore the effect of CqCaspase on WSSV replication, recombinant protein of CqCaspase (rCqCaspase) was delivered into Hpt cells followed by WSSV infection, which resulted in a significantly decreased expression of both an immediate early gene IE1 and a late envelope protein gene VP28 of WSSV, suggesting that CqCaspase, possibly by the enhanced apoptotic activity, had a strong negative effect on the WSSV replication. These data together indicated that CqCaspase was likely to play a vital role in immune defense against WSSV infection in a crustacean C. quadricarinatus, which shed a new light on the mechanism study of WSSV infection in crustaceans.

Eryptosis of non-parasitized erythrocytes is related to anemia in Plasmodium berghei low parasitema malaria of Wistar rats

It is known that premature elimination of non-parasitized RBCs (nRBCs) plays an important role in the pathogenesis of malarial anemia, in which suicidal death process (eryptosis) of nRBCs has been suggested to be involved. To check this possibility, we investigate eryptosis during infection of P. berghei ANKA in Wistar rats, a malaria experimental model that, similar to human malaria, the infection courses with low parasitemia and acute anemia. As expected, P. berghei ANKA infection was marked by low parasite burdens that reached a mean peak of 3% between days six and nine post-infection and solved spontaneously. A significant reduction of the hemoglobin levels (~ 30%) was also observed on days subsequent to the peak of parasitemia, persisting until day 16 post-infection. In eryptosis assays, it was observed a significant increase in the levels of PS-exposing nRBC, which coincided with the reduction of hemoglobin levels and was positively related to anemia. In addition to PS externalization, eryptosis of nRBC induced by P. berghei infection was characterized by cytoplasm calcium influx, but not caspases activity. These results confirm our previous studies evidencing a pro-eryptotic effect of malaria infection on nRBCs and show that a caspase-independent eryptotic process is implicated in anemia induced by P. berghei ANKA infection in Wistar rats.

Cerebellar Upregulation of Cell Surface Death Receptor-Mediated Apoptotic Factors in Harmaline-Induced Tremor: An Immunohistochemistry Study

Active caspase-3-mediated apoptosis has been implicated in the pathogenesis of harmaline-induced tremor. The aim of this study is to illustrate the impact of tremor induction on the expression of factors mediating the cell surface death receptor–dependent apoptosis. A total of 20 normal Wistar rats were randomly selected and equally divided into control and experimental groups. Tremor was induced in the experimental group by injecting the rats with a single dose of harmaline (50 mg/kg). After that, cerebellar tissues were evaluated by immunohistochemistry to examine the expression of tumor necrosis factor α (TNF-α) and active caspase-8 in the 2 groups of animals. TNF-α and active caspase-8 expression was significantly higher in cerebella from experimental rats compared with that in those from the control rats (P value < .01). Thus, our present data suggest the association of tremor induction with the cerebellar overexpression of TNF-α and active caspase-8, correlative with Purkinje cell (PC) loss indicated by loss of calbindin immunoreactivity, indicating the induction of the cell surface death receptor–mediated apoptosis.

Future Pharmacotherapy for Non-alcoholic Steatohepatitis (NASH): Review of Phase 2 and 3 Trials

Non-alcoholic steatohepatitis (NASH) results from inflammation and hepatocyte injury in the setting of hepatic steatosis. Non-alcoholic steatohepatitis increases the risk of progression to liver fibrosis and cirrhosis, and is the most rapidly growing etiology for liver failure and indication for liver transplantation in the USA. Weight loss and lifestyle modification remain the standard first-line treatment, as no USA Food and Drug Administration-approved pharmacotherapy currently exists. The past decade has seen an explosion of interest in drug development targeting pathologic pathways in non-alcoholic steatohepatitis, with numerous phase 2 and 3 trials currently in progress. Here, we concisely review the major targets and mechanisms of action by class, summarize results from completed pivotal phase 2 studies, and provide a detailed outline of key active studies with trial data for drugs in development, including obeticholic acid, elafibranor, cenicriviroc and selonsertib.

A novel caspase-associated recruitment domain (CARD) containing protein (CgCARDCP-1) involved in LPS recognition and NF-κB activation in oyster (Crassostrea gigas)

Caspase-associated recruitment domain (CARD) containing proteins play critical roles in molecular interaction and regulation of various signaling pathways, such as the activation of caspase and NF-κB singling pathway in the process of apoptosis or inflammation. In the present study, a novel CARD containing protein (designed CgCARDCP-1) was identified and characterized from oyster Crassostrea gigas. Molecular feature analysis revealed that, the open reading frame (ORF) of CgCARDCP-1 gene was 759 bp encoding a polypeptide of 253 amino acids with a conserved N-terminal CARD domain and two transcriptional coactivator p15 (PC4) domains in C-terminus. Homologous alignment showed that the amino acid sequence of CgCARDCP-1 shared 30%-46% identity with that of caspase-2. By RT-PCR detection, the mRNA transcripts of CgCARDCP-1 were found to be widely distributed in various tissues of oyster with the highest expression level in hemocytes and mantle. And CgCARDCP-1 protein was mostly distributed in the cytoplasm of oyster hemocytes as shown by immunohistochemistry. Moreover, the CgCARDCP-1 mRNA expression level in hemocytes was significantly up-regulated after lipopolysaccharide (LPS) and Vibrio splendidus stimulations. The recombinant CgCARDCP-1 displayed strong binding activity with LPS in vitro. In addition, after transfected into the HEK-293T cell with luciferase reporter system, CgCARDCP-1 could significantly promote the NF-κB activation (1.29-fold, p < 0.05) compared to that in the control group. These results collectively demonstrated that the CgCARDCP-1 might serve as a recognition molecule for LPS and a regulator of NF-κB activation in the immune response of oyster.

iTRAQ-based proteomic profile analysis of ISKNV-infected CPB cells with emphasizing on glucose metabolism, apoptosis and autophagy pathways

Infectious spleen and kidney necrosis virus (ISKNV) has caused significant losses in the cultured mandarin fish (Siniperca chuatsi) industry. The molecular mechanisms that underlie interaction between ISKNV and hosts are not fully understood. In this study, the proteomic profile of CPB cells at progressive time points after ISKNV infection was analyzed by isobaric tags for relative and absolute quantitation (iTRAQ). A total of 2731 proteins corresponding to 6363 novel peptides (false discovery rate <0.01) were identified. In the samples harvested 24 h (early-stage) and 72 h (late-stage) post-infection, 232 and 199 differentially expressed proteins were identified comparing with mock-infected cells, respectively. Western-blotting analysis of several proteins as G6PDH, β-tubulin and RPL11 were done to validate iTRAQ data. Among those differentially expressed proteins, several glucose metabolism-related enzymes, including glucose-6-phosphate dehydrogenase (G6PDH), pyruvate dehydrogenase phosphatase (PDP) and fumarate hydratase (FH), were up-regulated, while pyruvate dehydrogenase kinase (PDK) and enolase (ENO) were down-regulated at 24 h poi, suggesting that ISKNV enhanced glucose metabolism in CPB cells in early-stage infection. Simultaneously, expression of apoptosis-related proteins including Caspase 8, phosphoinositide 3-kinases (PI3Ks), and regulatory-associated protein of mTOR-like isoform X3 changed upon ISKNV infection, indicating that ISKNV induced apoptosis of CPB cells. Autophagy-related proteins including LC3 and PI3Ks were up-regulated at 24 h poi, indicating that ISKNV induced autophagy of CPB cells in early-stage infection. These findings may improve the understanding of ISKNV and host interaction and help clarify its pathogenesis mechanisms.

Catalytic Double Cyclization Process for Antitumor Agents against Breast Cancer Cell Lines

The development of efficient synthetic strategies for the discovery of novel antitumor molecules is a major goal in current research. In this context, we report here a catalytic double cyclization process leading to bicyclic heterocycles with significant antitumor activity on different human breast cancer (BC) cell lines. The products, 6,6a-dihydrofuro[3,2-b]furan-2(5H)-ones, were obtained in one step, starting from simple substrates (4-yne-1,3-diols, CO, and O2), under the catalytic action of PdI2 in conjunction with KI. These compounds have significant antiproliferative activity in vitro on human BC cell lines, both hormone receptor positive (MCF-7) and triple negative (triple-negative breast cancer [TNBC]; MDA-MB-231 and MDAMB-468), while exhibiting practically no effects on normal MCF-10A (human mammary epithelial) and 3T3-L1 (murine fibroblasts) cells. Thus, these compounds have the potential to expand the therapeutic options against BC, and in particular, against its most aggressive forms (TNBCs). Moreover, the present synthetic approach may provide an economic benefit for their production.

Role for Cystathionine γ Lyase (CSE) in an Ethanol (E)-Induced Lesion in Fetal Brain GSH Homeostasis

Earlier, we reported that gestational ethanol (E) can dysregulate neuron glutathione (GSH) homeostasis partially via impairing the EAAC1-mediated inward transport of Cysteine (Cys) and this can affect fetal brain development. In this study, we investigated if there is a role for the transulfuration pathway (TSP), a critical bio-synthetic point to supply Cys in E-induced dysregulation of GSH homeostasis. These studies utilized an in utero E binge model where the pregnant Sprague⁻Dawley (SD) rat dams received five doses of E at 3.5 g/kg by gastric intubation beginning embryonic day (ED) 17 until ED19 separated by 12 h. The postnatal day 7 (PN7) alcohol model employed an oral dosing of 4 g/kg body weight split into 2 feedings at 2 h interval and an iso-caloric and iso-volumic equivalent maltose-dextrin milk solution served as controls. The in vitro model consisted of cerebral cortical neuron cultures from embryonic day (ED) 16⁻17 fetus from SD rats and differentiated neurons from ED18 rat cerebral cortical neuroblasts. E concentrations were 4 mg/mL. E induced an accumulation of cystathionine in primary cortical neurons (PCNs), 2nd trimester equivalent in utero binge, and 3rd trimester equivalent PN7 model suggesting that breakdown of cystathionine, a required process for Cys supply is impaired. This was associated with a significant reduction in cystathionine γ-lyase (CSE) protein expression in PCN (p < 0.05) and in fetal cerebral cortex in utero (53%, p < 0.05) without a change in the expression of cystathionine β-synthase (CBS). Concomitantly, E decreased Cse mRNA expression in PCNs (by 32% within 6 h of exposure, p < 0.05) and in fetal brain (33%, p < 0.05). In parallel, knock down of CSE in differentiated rat cortical neuroblasts exaggerated the E-induced ROS, GSH loss with a pronounced caspase-3 activation and cell death. These studies illustrate the importance of TSP in CSE-related maintenance of GSH and the downstream events via Cys synthesis in neurons and fetal brain.

Maternal one carbon metabolism through increased oxidative stress and disturbed angiogenesis can influence placental apoptosis in preeclampsia

Adequate maternal nutrition is critical for a healthy pregnancy outcome and poor maternal nutrition is known to be associated with pregnancy complications like preeclampsia. We have earlier demonstrated that there is an imbalance in the levels of micronutrients (folate and vitamin B₁₂) along with low levels of long chain polyunsaturated fatty acids (LCPUFA) and high homocysteine levels in women with preeclampsia. Homocysteine is known to be involved in the formation of free radicals leading to increased oxidative stress. Higher oxidative stress has been shown to be associated with increased apoptotic markers in the placenta. Preeclampsia is of placental origin and is associated with increased oxidative stress, disturbed angiogenesis and placental apoptosis. The process of angiogenesis is important for placental and fetal development and various angiogenic growth factors inhibit apoptosis by inactivation of proapoptotic proteins through a series of cellular signalling pathways. We propose that an altered one carbon cycle resulting in increased oxidative stress and impaired angiogenesis will contribute to increased placental apoptosis leading to preeclampsia. Understanding the association of one carbon cycle components and the possible mechanisms through which they regulate apoptosis will provide clues for reducing risk of pregnancy complications.

Naringin inhibits ovarian tumor growth by promoting apoptosis: An in vivo study

The aim of the present study was to investigate the antitumor activities of naringin in ovarian cancer, and to assess the underlying mechanisms. Ovarian tumor cells were implanted into nude mice to produce ovarian tumors in vivo. The mice were divided into six groups: Control, low dose naringin [0.5 mg/kg, intraperitoneal (i.p.)], middle dose naringin (1 mg/kg, i.p.), high dose naringin (2 mg/kg, i.p.), positive control (cisplatin, 2 mg/kg, i.p.) and a combination of cisplatin and naringin (both 2 mg/kg). Following administration of naringin and/or cisplatin, the tumor size and weight were measured. Apoptosis of tumor cells was detected using a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Apoptosis-associated gene expression was detected using reverse transcription-polymerase chain reaction and immunohistochemistry. In the range of 0.5–2 mg/kg, naringin dose-dependently inhibited tumor growth, as demonstrated by a decrease in tumor size and weight. Naringin promoted apoptosis of the ovarian tumor cells. Additionally, naringin reduced the expression of B-cell lymphoma (Bcl)-2, Bcl-extra large (Bcl-xL), cyclin D1, c-Myc and survivin, while it increased the expression of caspase-3 and caspase-7. The data demonstrated that naringin inhibited ovarian tumor growth in vivo. Its mechanisms may be associated with caspase-7-, caspase-3-, Bcl-2- and Bcl-xL-mediated apoptosis. Nevertheless, the clinical application of naringin in the treatment of ovarian cancer requires further study.

Avenues to molecular imaging of dying cells: Focus on cancer

Successful treatment of cancer patients requires balancing of the dose, timing, and type of therapeutic regimen. Detection of increased cell death may serve as a predictor of the eventual therapeutic success. Imaging of cell death may thus lead to early identification of treatment responders and nonresponders, and to “patient‐tailored therapy.” Cell death in organs and tissues of the human body can be visualized, using positron emission tomography or single‐photon emission computed tomography, although unsolved problems remain concerning target selection, tracer pharmacokinetics, target‐to‐nontarget ratio, and spatial and temporal resolution of the scans. Phosphatidylserine exposure by dying cells has been the most extensively studied imaging target. However, visualization of this process with radiolabeled Annexin A5 has not become routine in the clinical setting. Classification of death modes is no longer based only on cell morphology but also on biochemistry, and apoptosis is no longer found to be the preponderant mechanism of cell death after antitumor therapy, as was earlier believed. These conceptual changes have affected radiochemical efforts. Novel probes targeting changes in membrane permeability, cytoplasmic pH, mitochondrial membrane potential, or caspase activation have recently been explored. In this review, we discuss molecular changes in tumors which can be targeted to visualize cell death and we propose promising biomarkers for future exploration.

Bovine herpesvirus type 5 replication and induction of apoptosis in vitro and in the trigeminal ganglion of experimentally-infected cattle

Bovine herpesvirus (BoHV) types 1 and 5 are neuroinvasive. Cases of BoHV-1-induced encephalitis are not as frequent as those caused by BoHV-5. In this study, the capability of BoHV-5 to induce apoptosis in cell cultures and in the trigeminal ganglion during acute infection of experimentally-infected cattle was analyzed. Apoptotic changes in cell cultures agree with the ability of the viral strains to replicate in each cell line. Marked differences were observed between the in vitro induction of apoptosis by BoHV-1Cooper and BoHV-5 97/613 strains. Apoptotic neurons were clearly evident in the trigeminal ganglion of BoHV-1-infected calves. For BoHV-5 a fewer number of positive neurons was observed. There is an association between the magnitude of bovine herpesviruses replication and the induction of apoptosis in trigeminal ganglion. These findings suggest that the induction of apoptosis and the innate immune response orchestrate the final outcome of alpha herpesviruses infection of the bovine nervous system.

Effects of indirubin and isatin on cell viability, mutagenicity, genotoxicity and BAX/ERCC1 gene expression

CONTEXT

Indigofera suffruticosa Miller (Fabaceae) and I. truxillensis Kunth produce compounds, such as isatin (ISA) and indirubin (IRN), which possess antitumour properties. Their effects in mammalian cells are still not very well understood.

OBJECTIVE

We evaluated the activities of ISA and/or IRN on cell viability and apoptosis in vitro, their genotoxic potentials in vitro and in vivo, and the IRN- and ISA-induced expression of ERCC1 or BAX genes.

MATERIALS AND METHODS

HeLa and/or CHO-K1 cell lines were tested (3 or 24 h) in the MTT, Trypan blue exclusion, acridine orange/ethidium bromide, cytokinesis-blocked micronucleus (CBMN) and comet (36, 24 and 72 h) tests after treatment with IRN (0.1 to 200 μM) or ISA (0.5 to 50 μM). Gene expression was measured by RT-qPCR in HeLa cells. Swiss albino mice received IRN (3, 4 or 24 h) by gavage (50, 100 and 150 mg/kg determined from the LD₅₀ - 1 g/kg b.w.) and submitted to comet assay in vivo.

RESULTS

IRN reduced the viability of CHO-K1 (24 h; 5 to 200 μM) and HeLa cells (10 to 200 μM), and was antiproliferative in the CBMN test (CHO-K1: 0.5 to 10 μM; HeLa: 5 and 10 μM). The drug did not induce apoptosis, micronucleus neither altered gene expression. IRN and ISA were genotoxic for HeLa cells (3 and 24 h) at all doses tested. IRN (100 and 150 mg/kg) also induced genotoxicity in vivo (4 h).

CONCLUSION

IRN and ISA have properties that make them candidates as chemotherapeutics for further pharmacological investigations.

Potential biological process of X-linked inhibitor of apoptosis protein in renal cell carcinoma based upon differential protein expression analysis

The X-linked inhibitor of apoptosis protein (XIAP) is the best characterized member of the IAP family and is a potent inhibitor of the caspase/apoptosis pathway. It has also been revealed that XIAP has additional biological functions that rely on its direct inhibition of apoptosis. In the present study, stably transfected Caki-1 cells with XIAP-knockdown were generated, and an isobaric tag for relative and absolute quantitation-based proteomics approach was employed to investigate the regulatory mechanism of XIAP in renal cell carcinoma (RCC). The results demonstrate that the sensitivity of the RCC cell line to apoptotic stimulation increased markedly with XIAP-knockdown. A number of differentially expressed proteins were detected between the original Caki-1 cell line and the XIAP-knockdown Caki-1 cell line; 87 at 0 h (prior to etoposide treatment), 178 at 0.5 h and 169 at 3 h, while no differentially expressed proteins were detected (ratio >1.5 or <0.5; P<0.05) at 12 h after etoposide treatment. Through analysis of the differentially expressed proteins, it was revealed that XIAP may participate in the tumor protein p53 pathway, the Wnt signaling pathway, glucose metabolism, endoplasmic reticulum stress, cytoskeletal regulation and DNA repair. These results indicate that XIAP may have a number of biological functions and may provide an insight into the biomedical significance of XIAP overexpression in RCC.

XIAP underlies apoptosis resistance of renal cell carcinoma cells

X-linked inhibitor of apoptosis (XIAP), a key member of the inhibitors of apoptosis protein family, can inhibit apoptosis by directly binding to the initiator caspase-9, −3 and −7, thereby promoting tumor cell survival during tumor progression. In the present study, XIAP basal expression levels were investigated and its contribution to the resistance to apoptosis was evaluated, in the RCC cell lines exposed to apoptosis-inducing drugs. This was investigated by histological methods and western blot analysis. Using RNA interference, elimination of XIAP in Caki-1 cells was also studied, and its contribution to the sensitivity to apoptosis induced through the intrinsic pathway was observed. Differences in XIAP expression were detected between ClearCa-2 and ClearCa-6 cell lines. ClearCa-6 cells with lower expression of XIAP were more sensitive to apoptosis-inducing drugs, compared with ClearCa-2 cells. However, the levels of XIAP expression in both cell lines were stable during apoptosis. Furthermore, a Caki-1 cell line with no XIAP expression was used, and was demonstrated to be more sensitive to the apoptosis induced by the mitochondrial pathway. These results suggested that downregulation of XIAP expression could enhance the sensitivity of RCC cells to apoptosis, and the basal expression of XIAP during apoptosis is stable. This may provide novel insight for targeted gene therapy against XIAP, in the clinic.

Hepatoprotective Effects of Kaempferol-3-O-α-l-Arabinopyranosyl-7-O-α-l-Rhamnopyranoside on d-Galactosamine and Lipopolysaccharide Caused Hepatic Failure in Mice

Fulminant hepatic failure (FHF), associated with high mortality, is characterized by extensive death of hepatocytes and hepatic dysfunction. There is no effective treatment for FHF. Several studies have indicated that flavonoids can protect the liver from different factor-induced injury. Previously, we found that the extracts of Elaeagnus mollis leaves had favorable protective effects on acute liver injury. However, the role and mechanisms behind that was elusive. This study examined the hepatoprotective mechanisms of kaempferol-3-O-α-l-arabinopyranosyl-7-O-α-l-rhamnopyra-noside (KAR), a major flavonol glycoside of E. mollis, against d-galactosamine (GalN) and lipopolysaccharide (LPS)-induced hepatic failure. KAR reduces the mouse mortality, protects the normal liver structure, inhibits the serum aspartate aminotransferase (AST) and alamine aminotransferase (ALT) activity and decreases the production of malondialdehyde (MDA) and reactive oxygen species (ROS) and inflammatory cytokines, TNF-α, IL-6, and IL-1β. Furthermore, KAR inhibits the apoptosis of hepatocytes and reduces the expression of TLR4 and NF-κB signaling pathway-related proteins induced by GalN/LPS treatment. These findings suggest that the anti-oxidative, anti-inflammatory, and anti-apoptotic effects of KAR on GalN/LPS-induced acute liver injury were performed through down-regulating the activity of the TLR4 and NF-κB signaling pathways.

Effects of baicalein on proliferation, apoptosis, migration and invasion of Ewing's sarcoma cells

Ewing's sarcoma (ES) is a rare tumor that is more frequent in pediatric and adolescent age groups. In the past few decades, long-term survival in affected patients has improved due to the success of multimodal therapy. However, long-term survival is inevitably restricted by the late side-effects of chemotherapy. Besides, early metastasis also contributes to the poor prognosis of ES. Recently, traditional Chinese medicines (TCMs) have increasingly attracted interest due to the promising clinical results and fewer side-effects for the treatment of cancers. Among the various TCMs, the root of Scutellaria baicalensis exerts anti-inflammatory properties as a well-known herb in traditional Chinese medicine. Baicalein (5,6,7-trihydroxyflavone) derived from the root of Scutellaria baicalensis is a bioactive compound, which possesses a powerful pro-apoptotic activity in various cancers such as hepatocellular carcinoma and myeloma. However, the effects of baicalein on ES cells remain still unknown. We anticipated that baicalein also has apoptotic activity in ES. The aim of the present study was to investigate the effects of baicalein on viability, apoptosis, migration and invasion of ES cells, and further to elaborate the molecular mechanism of baicalein-induced ES cell apoptosis. We found that baicalein markedly inhibited ES cells viability in a time- and dose-dependent manner, especially SK-ES-1 cells and could promote the apoptosis of ES cells. Additionally, baicalein was capable of upregulating the expression of the pro-apoptotic proteins Bax and cytochrome c, reducing the expression of the anti-apoptotic protein Bcl-2, elevating the ratio of Bax/Bcl-2, and triggering the mitochondrial apoptotic pathway, which led to caspase-3 and caspase-9 activation and PARP cleavage. Meanwhile, the activation of caspase-8 and the death receptor pathway was also observed. Besides, baicalein could reduce ES migration and invasion in vitro, which showed its potential to inhibit ES metastasis, besides contributing to the decrease in the expression of matrix metalloproteinases (MMP)-2 and MMP-9. In conclusion, baicalein has a potent tumor-suppressor activity by inducing cell apoptosis through the mitochondrial apoptotic pathway and the death receptor pathway in ES cells, thus it may serve as a novel and effective candidate agent for ES treatment.

Antinflammatory and anticancer effects of terpenes from oily fractions of Teucruim alopecurus, blocker of IκBα kinase, through downregulation of NF-κB activation, potentiation of apoptosis and suppression of NF-κB-regulated gene expression

Teucrium alopecurus is an endemic plant limited to southern Tunisia. In the present study, the chemical composition, anticancer and nuclear factor-κB (NF-κB) inhibitory effects of Teucrium alopecurus leaf essential oil was investigated. The analysis of Teucrium alopecurus (TA-1) with Gas Chromatography-Mass Spectrometry (GC/MS) showed that α-Bisabolol, (+)-epi-Bicyclosesquiphellandrene and α-Cadinol, were found in relatively high amounts (16.16%, 15.40% and 8.52%, respectively). Cell viability was determined by 3-(4-5-dimethylthiazol-2-yl) 2-5-diphenyl-tetrazolium (MTT) assay. Cell cycle and apoptosis assay were determined by flow cytometry. TA-1 functions as an anticancer agent by triggering apoptosis potentiated by chemotherapeutic agents and TNF in human myeloid leukemia cells (KBM5) through a mechanism involving poly(ADP-ribose) polymerase (PARP) cleavage and initiator and effector caspases activation. Moreover, electrophoretic mobility shift assay (EMSA) revealed that TA-1 downregulated nuclear localization of NF-κB and its phosphorylation induced by TNF-α and this, allows the suppression of the degradation and phosphorylation of IκB and the inhibition of the phosphorylation of p65 phosphorylation and the p50-p65 heterodimer nuclear translocation, causing attenuation of NF-κB-regulated antiapoptotic (Survivin, Bcl-2, c-IAP1/2, Bcl-xL, Mcl-1, and cFLIP), invasion (ICAM1), metasatsis (MMP-9), and angiogenesis (VEGF) gene expression in KBM5; and finally reporter gene expression. Furthermore, treatment with essential oil and TNF-α suppressed the NF-κB DNA binding activity. Finally, the activation of nuclear factor-κB induced by different plasmids (TNFR1, TRADD, TRAF2, NIK, TAK1/TAB1, and IKKβ) was inhibited following treatment with TA-1. Overall, TA-1 inhibits NF-κB activation and further growth and proliferation of cancer cells.

Antitumorpharmacological mechanism of the oral liquid of Poriacocos polysaccharide

ETHNOPHARMACOLOGICAL RELEVANCE

The liquid oral formulation of Poria cocos polysaccharides is composed of polysaccharides of Lentinusedodes, Ganodermalucidum and Poria cocos(1:1:2), which are all fungi used in traditional Chinese medicine. Polysaccharides extracted from these fungi have been reported to exhibit an antitumor effect by modulating the immune system.

AIM OF THE STUDY

The present study aimed to clarify the antitumor mechanism of an orally administered liquid containing Poriacocos and to further provide clinical guidance.

MATERIALS AND METHODS

In this study, the effects of an orally administered liquid containing Poriacocos polysaccharides on the solid tumors formed from sarcoma 180 cells in mice were evaluated. The protein expression of Bcl-2, caspase-3, and caspase-9in the thymus, spleen and liver tissues in the mice was determined by Western blot analysis. In addition, hematoxylin-eosin（H&E）staining and immunohistochemistry were performed on thymus, spleen and liver tissue and the positive staining rate was calculated for the three protein expression.

RESULTS

The liquid oral formulation of Poriacocos polysaccharides reduced Bcl-2 protein levels and increased caspase-3 and -9 protein levels in sarcoma 180 cells.

CONCLUSION

The mechanism underlying the antitumor effects of the oral liquid formulation of Poriacocos polysaccharides involved inhibition of Bcl-2 expression and activation of caspase-9 expression in sarcoma 180 cells. Furthermore, the downstream caspase-3 promoter cascade was activated and cell apoptosis was activated in sarcoma 180 cells.

Thermotolerance, oxidative stress, apoptosis, heat-shock proteins and damages to reproductive cells of insecticide-susceptible and -resistant strains of the diamondback moth Plutella xylostella

In this study, we investigated thermotolerance, several physiological responses and damage to reproductive cells in chlorpyrifos-resistant (Rc) and -susceptible (Sm) strains of the diamondback moth, Plutella xylostella subjected to heat stress. The chlorpyrifos resistance of these strains was mediated by a modified acetylcholinesterase encoded by an allele, ace1R, of the ace1 gene. Adults of the Rc strain were less heat resistant than those of the Sm strain; they also had lower levels of enzymatic activity against oxidative damage, higher reactive oxygen species contents, weaker upregulation of two heat shock protein (hsp) genes (hsp69s and hsp20), and stronger upregulation of two apoptotic genes (caspase-7 and -9). The damage to sperm and ovary cells was greater in Rc adults than in Sm adults and was temperature sensitive. The lower fitness of the resistant strain, compared with the susceptible strain, is probably due to higher levels of oxidative stress and apoptosis, which also have deleterious effects on several life history traits. The greater injury observed in conditions of heat stress may be due to both the stronger upregulation of caspase genes and weaker upregulation of hsp genes in resistant than in susceptible individuals.

Transcriptome analysis of the immune reaction of the pearl oyster Pinctada fucata to xenograft from Pinctada maxima

The pearl oyster Pinctada maxima exhibits great difficulty to culture pearls through nuclear insertion with an allograft, but it is easy for P. fucata to culture pearls after allografting. If P. fucata could be used as a surrogate mother to culture P. maxima pearls, it would benefit the pearl culture industry of P. maxima. However, this is blocked by the immune rejection of P. fucata against P. maxima mantle grafts. In this study, the immune responses of P. fucata hemocyte to allograft and xenograft were investigated after transplantation by transcriptome analysis. In total, 107.93 Gb clean reads were produced and assembled using the reference genome of P. fucata. Gene Ontology Term enrichment and KEGG enrichment analyses indicated that apoptosis, hippo signaling pathway, oxidation-reduction, MAPK signaling pathway, ribosome, protein processing in endoplasmic reticulum, purine metabolism, NF-kappa B signaling pathway, oxidative phosphorylation, Ras signaling pathway, and ubiquitin mediated proteolysis were involved in response to transplantation. Many genes related to oxidation-reduction reactions, the MAPK signaling pathway, and apoptosis were identified by comparison of the allograft group and the xenograft group at 0 h, 6 h, 12 h, 24 h, 48 h, 72 h, and 96 h post-transplantation. Among them, the expression levels of NADH dehydrogenase, succinate dehydrogenase and other dehydrogenases were increased significantly in the xenograft groups compared with allograft groups at 0 h post transplantation, indicating that a respiratory burst of neutrophils occurred immediately after xenograft transplantation. Additionally, HSP70 was highly expressed from 0 h to 96 h in the xenograft groups, indicating an oyster immune response to the xenograft. The genes enriched in the ribosome and hippo-signaling pathways were also identified, and expression patterns of these DEGs were different as compared between transplantation and control groups. Finally, altered expression levels of 10 randomly selected immune-related DEGs were confirmed by quantitative real-time PCR. These results indicated that oxidation-reduction is likely the key factor responsible for immune rejection to transplantation. The findings should provide some new insight into the molecular mechanism of immune rejection of the host against xenograft, and thus benefit to development of immunosuppressive reagents to facilitate effective xenograft pearling.

Knowledge-transfer learning for prediction of matrix metalloprotease substrate-cleavage sites

Matrix Metalloproteases (MMPs) are an important family of proteases that play crucial roles in key cellular and disease processes. Therefore, MMPs constitute important targets for drug design, development and delivery. Advanced proteomic technologies have identified type-specific target substrates; however, the complete repertoire of MMP substrates remains uncharacterized. Indeed, computational prediction of substrate-cleavage sites associated with MMPs is a challenging problem. This holds especially true when considering MMPs with few experimentally verified cleavage sites, such as for MMP-2, -3, -7, and -8. To fill this gap, we propose a new knowledge-transfer computational framework which effectively utilizes the hidden shared knowledge from some MMP types to enhance predictions of other, distinct target substrate-cleavage sites. Our computational framework uses support vector machines combined with transfer machine learning and feature selection. To demonstrate the value of the model, we extracted a variety of substrate sequence-derived features and compared the performance of our method using both 5-fold cross-validation and independent tests. The results show that our transfer-learning-based method provides a robust performance, which is at least comparable to traditional feature-selection methods for prediction of MMP-2, -3, -7, -8, -9 and -12 substrate-cleavage sites on independent tests. The results also demonstrate that our proposed computational framework provides a useful alternative for the characterization of sequence-level determinants of MMP-substrate specificity.

pH-dependent general base catalyzed activation rather than isocyanate liberation may explain the superior anticancer efficacy of laromustine compared to related 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine prodrugs

Laromustine (also known as cloretazine, onrigin, VNP40101M, 101M) is a prodrug of 90CE, a short-lived chloroethylating agent with anticancer activity. The short half-life of 90CE necessitates the use of latentiated prodrug forms for in vivo treatments. Alkylaminocarbonyl-based prodrugs such as laromustine exhibit significantly superior in vivo activity in several murine tumor models compared to analogs utilizing acyl, and alkoxycarbonyl latentiating groups. The alkylaminocarbonyl prodrugs possess two exclusive characteristics: (i) They are primarily unmasked by spontaneous base catalyzed elimination; and (ii) they liberate a reactive carbamoylating species. Previous speculations as to the therapeutic superiority of laromustine have focused upon the inhibition of enzymes by carbamoylation. We have investigated the therapeutic interactions of analogs with segregated chloroethylating and carbamoylating activities (singly and in combination) in the in vivo murine L1210 leukemia model. The combined treatment with chloroethylating and carbamoylating prodrugs failed to result in any synergism and produced a reduction in the therapeutic efficacy compared to the chloroethylating prodrug alone. Evidence supporting an alternative explanation for the superior tumor selectivity of laromustine is presented that is centered upon the high pH sensitivity of its base catalyzed activation, and the more alkaline intracellular pH values commonly found within tumor cells.

Caspase-3-dependent cleavage of Akt modulates tau phosphorylation via GSK3β kinase: implications for Alzheimer's disease

The pathological hallmark of Alzheimer's disease (AD) is accumulation of misfolded amyloid-β peptides and hyperphosphorylated tau protein in the brain. Increasing evidence suggests that serine-aspartyl proteases-caspases are activated in the AD brain. Previous studies identified a caspase-3 cleavage site within the amyloid-β precursor protein, and a caspase-3 cleavage of tau as the mechanisms involved in the development of Aβ and tau neuropathology, respectively. However, the potential role that caspase-3 could have on tau metabolism remains unknown. In the current studies, we provide experimental evidence that caspase-3 directly and specifically regulates tau phosphorylation, and demonstrate that this effect is mediated by the GSK3β kinase pathway via a caspase-3-dependent cleavage of the protein kinase B (also known as Akt). In addition, we confirm these results in vivo by using a transgenic mouse model of AD. Collectively, our findings demonstrate a new role for caspase-3 in the neurobiology of tau, and suggest that therapeutic strategies aimed at inhibiting this protease-dependent cleavage of Akt may prove beneficial in preventing tau hyperphosphorylation and subsequent neuropathology in AD and related tauopathies.

Lectin CGL from the sea mussel Crenomytilus grayanus induces Burkitt's lymphoma cells death via interaction with surface glycan

Marine organisms are rich sources of lectins. Lectins are able to bind specifically and reversibly to different types of carbohydrates or glycoproteins. The present study reports the evaluation of glycan binding profile and anti-tumor potential of lectin CGL from the sea mussel Crenomytilus grayanus. Glycan array assay revealed that CGL was able to bind both α and β anomer of galactose, but interaction with the αGal-terminated glycans was stronger. Analysis of most common glycan motifs for CGL showed high affinity to Galα1-4Galβ1-4GlcNAc motif similar to globotriose structure (Gb3: Galα1-4Galβ1-4Glc), the epitope of globotriaosylceramide. CGL recognized Gb3 on the surface of Burkitt's lymphoma Raji cells (high Gb3 expression), leading to dose-dependent cytotoxic effect, G2/M phase cell cycle arrest and apoptosis. Lectin had no effect on erythroleukemia K562 cells (no Gb3 expression). The activity of CGL was specifically blocked by α-galactoside. Our findings suggest the use of CGL in cancer diagnosis and treatment.

Cancer-Associated, Stimuli-Driven, Turn on Theranostics for Multimodality Imaging and Therapy

Advances in bioinformatics, genomics, proteomics, and metabolomics have facilitated the development of novel anticancer agents that have decreased side effects and increased safety. Theranostics, systems that have combined therapeutic effects and diagnostic capabilities, have garnered increasing attention recently because of their potential use in personalized medicine, including cancer-targeting treatments for patients. One interesting approach to achieving this potential involves the development of cancer-associated, stimuli-driven, turn on theranostics. Multicomponent constructs of this type would have the capability of selectively delivering therapeutic reagents into cancer cells or tumor tissues while simultaneously generating unique signals that can be readily monitored under both in vitro and in vivo conditions. Specifically, their combined anticancer activities and selective visual signal respond to cancer-associated stimuli, would make these theranostic agents more highly efficient and specific for cancer treatment and diagnosis. This article focuses on the progress of stimuli-responsive turn on theranostics that activate diagnostic signals and release therapeutic reagents in response to the cancer-associated stimuli. The present article not only provides the fundamental backgrounds of diagnostic and therapeutic tools that have been widely utilized for developing theranostic agents, but also discusses the current approaches for developing stimuli-responsive turn on theranostics.

A Selenium-Enriched Ziyang Green Tea Polysaccharide Induces Bax-Dependent Mitochondrial Apoptosis and Inhibits TGF-β1-Stimulated Collagen Expression in Human Keloid Fibroblasts via NG2 Inactivation

Keloids are fibroproliferative disorders characterized by the overabundant deposition of extracellular matrix (ECM), especially collagen and overgrowth of scar tissue in response to cutaneous injury. In this study, we isolated a selenium (Se)-containing polysaccharide (Se-ZGTP-I) from Ziyang green tea and explored its potential therapeutic effects on keloid fibroblasts formation. 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and annexin V/propidium iodide (PI) staining assays demonstrated that Se-ZGTP-I or neuron-glia 2 (NG2) short hairpin RNA (shRNA) significantly inhibited proliferation of human keloid fibroblasts via induction of apoptosis. Besides, the activation of caspase-3 and the subsequent cleavage of poly (ADP-ribose) polymerase (PARP) were observed in keloid fibroblasts following Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA treatment. Moreover, Western blotting analysis showed that treatment of keloid fibroblasts with Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA resulted in an increase of pro-apoptotic protein Bax expression and a decrease in expression levels of anti-apoptotic protein Bcl-2 and NG2. In addition, type I collagen biosynthesis and protein expression in keloid fibroblasts following TGF-β1 stimulation were decreased by Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA management. Current findings imply that Se-ZGTP-I has a therapeutic potential to intervene and prevent keloid formation and other fibrotic diseases.

Nano-Armoring of Enzymes: Rational Design of Polymer-Wrapped Enzymes

The formulation in which therapeutic proteins are administered plays a key role in retaining their biological activity. Enzyme wrapping, using synthetic polymers, is a strategy employed to provide enzymes with lower immunogenicity, longer circulation times, and better targeting capabilities. Protein-polymer complexation methods, involving covalent, noncovalent, and electrostatic interactions, that can provide means to develop formulations for retaining enzyme stability are discussed in this chapter. Amphiphilic self-cross-linkable polymer was used to encapsulate capsase-3 enzyme in the nanogel, while inverse emulsion polymerization method was used to entrap α-glucosidase enzyme in the nanogel. These nanogels were characterized by dynamic light scattering, transmission electron microscopy, and gel electrophoresis. Upon release of caspase-3 enzyme from polymeric nanogel, it retained nearly 86% of its original activity. Similarly, α-glucosidase that was encased in the acid cleavable polymeric nanogel exhibited substantial activity after release under acidic conditions (pH 5, 48h). Nano-armoring of the enzymes were nearly complete and provided high yields of the encased enzyme.

Induction of Bex genes by curcumin is associated with apoptosis and activation of p53 in N2a neuroblastoma cells

Brain expressed X-linked (Bex) genes are newer group of pro-apoptotic genes. Role of any Bex gene in neuroblastoma and Bex4 and Bex6 in any cancer is completely unknown. Re-expression of all endogenous Bex genes by any nutraceutical is also unknown. Therefore, we investigated the induction of all endogenous Bex genes and associated mechanisms by curcumin using N2a, an aggressive neuroblastoma cell line. Curcumin induced all endogenous Bex genes prior to apoptosis in N2a cells in a dose- and time-dependent manner. Wortmannin (PI-3Kinases inhibitor), SP600125 (JNK inhibitor) and pifithrin-α (p53 inhibitor) abrogated curcumin-mediated induction of Bex genes. Inhibition of curcumin-mediated induction of Bex genes by pifithrin-α also inhibited N2a cells apoptosis suggesting, a direct role of Bex genes in N2a cells apoptosis and involvement of p53 in Bex genes induction. Curcumin treatment activated p53 through hyperphosphorylation at serine 15 before Bex genes induction indicating Bex genes are novel downstream targets of p53. Collectively, curcumin, a safe nutraceutical has the potential to induce all endogenous Bex genes to harness their anti-cancer properties in neuroblastoma cells. Re-expression of Bex genes by curcumin acts as tumor suppressors and may provide alternate strategy to treat neuroblastomas and other cancers with silenced Bex genes.

Influence of nanoporous poly(ether imide) particle extracts on human aortic endothelial cells (HAECs)

Accumulated uremic toxins like indoxyl sulphate, hippuric acid and p-cresyl sulphates in renal failure patients stimulate proinflammatory effects, and consequently kidney and cardiovascular diseases. Low clearance rate of these uremic toxins from the blood of uremic patients by conventional techniques like hemodialysis is due to their strong covalent albumin binding (greater than 95%) and hydrophobic nature, which led to alternatives like usage of hydrophobic adsorber's in removing these toxins from the plasma of kidney patients. Polymers like polyethylene, polyurethane, polymethylmethacrylate, cellophane and polytetrafluoroethylene were already in use as substitutes for metal devices as dialysis membranes. Among new synthetic polymers, one such ideal adsorber material are highly porous microparticles of poly(ether imide) (PEI) with diameters in the range from 50-180μm and a porosity around 88±2% prepared by a spraying and coagulation process.It is essential to make sure that these synthetic polymers should not evoke any inflammatory or apoptotic response during dialysis. Therefore in our study we evaluated in vitro effect of PEI microparticle extracts in human aortic endothelial cells (HEACs) concerning toxicity, inflammation and apoptosis. No cell toxicity was observed when HAECs were treated with PEI extracts and inflammatory/apoptotic markers were not upregulated in presence of PEI extracts. Our results ensure biocompatibility of PEI particles and further hemocompatibility of particles will be tested.

Detecting Cleaved Caspase-3 in Apoptotic Cells by Flow Cytometry

Apoptosis is orchestrated by caspases, a family of cysteine proteases that cleave their substrates on the carboxy-terminal side of specific aspartic acid residues. These proteases are generally present in healthy cells as inactive zymogens, but when stimulated they undergo autolytic cleavage to become fully active. They subsequently cleave their substrates at one or two specific sites, which can result in activation, inactivation, relocalization, or remodeling of the substrate. Consequently, many of the cleaved fragments remain intact during apoptosis and can be detected using substrate-specific antibodies. These fragments are most commonly detected by western blotting, which resolves proteins and their fragments based on molecular mass. However, antibodies that only recognize cleaved fragments can be used to specifically label cells in which caspase cleavage has occurred. It is then possible to quantify these cells by flow cytometry. A number of antibodies that specifically recognize caspase-cleaved fragments have been generated, including antibodies that recognize the cleaved form of caspase-3. This caspase is responsible for the majority of proteolysis during apoptosis, and detection of cleaved caspase-3 is therefore considered a reliable marker for cells that are dying, or have died by apoptosis. This protocol outlines the quantification of apoptosis by flow cytometric detection of cleaved caspase-3.

Using the Baculovirus/Insect Cell System to Study Apoptosis

Apoptosis is a physiological program of cell suicide conserved in invertebrates and vertebrates. Apoptosis is crucial to the normal development of organisms and in tissue homeostasis by promoting elimination of unwanted cells, including damaged or virus-infected cells. Due to the importance of programmed cell death for the survival of the organism, a tight regulation is exerted at various activation levels of the cell-death machinery. The utilization of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) to identify genes that inhibit the apoptotic process will be described using a transfection-based approach, illustrated by identification of the p49 gene.

Expression of caspase 3 in ovarian follicle cells of the lizard Podarcis sicula

In this study, our aim was to determine whether caspase 3 plays a role, during previtellogenesis, in the ovarian follicular epithelium of the lizard Podarcis sicula. We investigated the presence and localization of proform and active caspase 3 by enzyme assay, Western blotting and immunocytochemistry. In parallel, a fragment of caspase 3 was cloned for the first time in this species, sequenced and used for in situ hybridization to localize messengers and analysed by a phylogenetic survey to shed light on its homology with reptilian caspases. Results demonstrated that: (1) the follicle cells expressed a caspase of the 3/7 group and the mRNA for caspase 3 was transcribed in the stem phase and was completely translated during cell differentiation; (2) the proform protein was stored during the differentiated (nurse) stage and activated at the end of previtellogenesis provoking the degeneration of cells; (3) the predicted protein sequence, although partial, had a strong similarity with the known reptilian caspases 3. The epithelial cells of the ovarian follicle, therefore, do not employ caspase 3 during the nurse stage but, instead, prepare for apoptosis long before the process actually begins. The relevance of this strategy is discussed.

Apoptosis in the Trophoblast—Role of Apoptosis in Placental Morphogenesis

Villous trophoblast is the epithelial cover of the placental villous tree and comes in direct contact with maternal blood. The turnover of villous trophoblast includes proliferation and differentiation of cytotrophoblast, syncytial fusion of cytotrophoblast with the overlying syncytiotrophoblast, differentiation in the syncytiotrophoblast, and finally extrusion of apoptotic material into the maternal circulation. In recent years, it has become clear that apoptosis is a normal constituent of trophoblast turnover and the release of apoptotic material does not lead to an inflammatory response of the mother. During preeclampsia there seems to be an altered balance between proliferation and apoptosis of villous trophoblast leading to a dysregulation of the release from the syncytiotrophoblast. The normal apoptotic release may be reduced in favor of a necrotic release. Since apoptosis is still ongoing in the syncytiotrophoblast, a necrotic release of intrasyncytial and partly apoptotic material lead us to call this type of release "aponecrotic shedding." In this situation, cell-free components such as G-actin and DNA freely floating in maternal blood may trigger damage to the maternal endothelium, thereby triggering preeclampsia. This review highlights the importance of the apoptosis cascade in permitting normal physiologic turnover of villous trophoblast. It will demonstrate the participation of initial stages of this cascade within the cytotrophoblast and of the execution stages within the syncytiotrophoblast. Moreover, this review presents hypotheses of how dysregulation of the apoptosis cascade may be linked to endothelial dysfunction of the maternal vasculature in preeclampsia.

Filifactor alocis collagenase can modulate apoptosis of normal oral keratinocytes

To successfully colonize host cells, pathogenic bacteria must circumvent the host's structural barrier such as the collagen-rich extracellular matrix (ECM), as a preliminary step to invasion and colonization of the periodontal tissue. Filifactor alocis possesses a putative Peptidase U32 family protein (HMPREF0389_00504) with collagenase activity that may play a significant role in colonization of host tissue during periodontitis by breaking down collagen into peptides and disruption of the host cell. Domain architecture of the HMPREF0389_00504 protein predicted the presence of a characteristic PrtC-like collagenase domain, and a peptidase domain. Our study demonstrated that the recombinant F. alocis peptidase U32 protein (designated PrtFAC) can interact with, and degrade, type I collagen, heat-denatured collagen and gelatin in a calcium-dependent manner. PrtFAC decreased viability and induced apoptosis of normal oral keratinocytes (NOKs) in a time and dose-dependent manner. Transcriptome analysis of NOK cells treated with PrtFAC showed an upregulation of the genes encoding human pro-apoptotic proteins: Apoptotic peptidase activating factor 1 (Apaf1) cytochrome C, as well as caspase 3 and caspase 9, suggesting the involvement of the mitochondrial apoptotic pathway. There was a significant increase in caspase 3/7 activity in NOK cells treated with PrtFAC. Taken together, these findings suggest that F. alocis PrtFAC protein may play a role in the virulence and pathogenesis of F. alocis.

MicroRNA-224 aggrevates tumor growth and progression by targeting mTOR in gastric cancer

Growing evidence suggests that microRNA plays an essential role in the development and metastasis of many tumors, including gastric cancer. Aberrant miR-224 expression has been indicated in tumor growth, the mechanism of miR-224 promoting the proliferation and metastatic ability for gastric cancer remains unclear. Accumulating evidence reports that mTOR signal pathway plays an important role in the cellular process, such as apoptosis, cell growth and proliferation. The goal of the present study was to identify whether miR-224 could inhibit the growth, migration, invasion, proliferation and metastasis of gastric cancer through targeting mTOR expression. Real-time PCR (RT-PCR) was used to quantify miR-224 expression in vitro and in vivo experiments. Luciferase reporter assays were performed to confirm the activity of mTOR pathway, and immunofluorescence staining assay was conducted to observe apoptosis and cell proliferation ability. Bioinformatics as well as cell luciferase function studies distinguished the direct modulation of miR-224 on the 3'-UTR of the mTOR, which leads to the inactivation of apoptosis signaling and the activation of cell proliferation. In addition, inhibition of miR-224 significantly reduced the expression of mTOR and improved caspase-9/3 expression while decreased cyclin D1/2 levels, attenuating gastric cancer cell proliferation. Therefore, the present study revealed the mechanistic links between miR-224 and mTOR in the pathogenesis of gastric cancer through modulation of caspase-9/3 and cyclin D1/2. In addition, targeting miR-224 could serve as a novel strategy for future gastric cancer therapy.

Leptin reduces apoptosis triggered by high temperature in human placental villous explants: The role of the p53 pathway

Maternal fever is common during pregnancy and has for many years been suspected to harm the developing fetus. Whether increased maternal temperature produces exaggerated apoptosis in trophoblast cells remains unclear. Since p53 is a critical regulator of apoptosis we hypothesized that increased temperature in placenta produces abnormal expression of proteins in the p53 pathway and finally caspase-3 activation. Moreover, leptin, produced by placenta, is known to promote the proliferation and survival of trophoblastic cells. Thus, we aimed to study the possible role of leptin preventing apoptosis triggered by high temperature, as well as the molecular mechanisms underlying this effect. Fresh placental tissue was collected from normal pregnancies. Explants of placental villi were exposed to 37 °C, 40 °C and 42 °C during 3 h in the presence or absence of 10 nM leptin in DMEM-F12 medium. Western blotting and qRT-PCR was performed to analyze the expression of p53 and downstream effector, P53AIP1, Mdm2, p21, BAX and BCL-2 as well as the activated cleaved form of caspase-3 and the fragment of cytokeratin-18 (CK-18) cleaved at Asp396 (neoepitope M30). Phosphorylation of the Ser 46 residue on p53, the expression of P53AIP1, Mdm2, p21, as well as caspase-3 and CK-18 were significantly increased in explants at 40 °C and 42 °C. Conversely, these effects were significantly attenuated by leptin 10 nM at both 40 °C and 42 °C. The BCL2/BAX ratio was also significantly decreased in explants at 40 °C and 42 °C compared with explants incubated at 37 °C, which was prevented by leptin stimulation. These data illustrate the potential role of leptin for reducing apoptosis in trophoblast explants, including trophoblastic cells, triggered by high temperature, by preventing the activation of p53 signaling.

Apoptosis-mediated testicular alteration in Japanese quail (Coturnix coturnix japonica) in response to temporal phase relation of serotonergic and dopaminergic oscillations

Reproductive performance of many avian species, including Japanese quail, is reported to be modulated by specific temporal phase relation of serotonergic and dopaminergic oscillations. Accordingly, it has been shown that the serotonin precursor 5-HTP and the dopamine precursor l-DOPA given 8 h apart induce gonadal suppression and given 12 h apart lead to gonadal stimulation, while other temporal relationships were found to be ineffective. In the present study, we investigated the effects of 8- and 12-h phase relation of neural oscillations on testicular responses including expression of GnRH-I, GnIH, pro-apoptotic proteins (p53 and Bax), inactive and active executioner caspase-3, and the uncleaved DNA repair enzyme PARP-1. Testicular volume and mass decreased significantly in 8-h quail and increased in 12-h quail compared with controls. Expression of ir-GnIH, p53, Bax and active-caspase-3 increased and that of GnRH-I, pro-caspase-3 and uncleaved PARP-1 decreased in 8-h quail compared with controls. A TUNEL assay also confirmed testicular regression in these quail. Testes of 12-h quail exhibited significantly increased expression of GnRH-I, pro-caspase-3 and uncleaved PARP-1 compared with the control group. Our findings suggest that differential response of avian testes to 8- and 12-h phase relation of serotonergic and dopaminergic neural oscillations may be attributed to autocrine/paracrine action of GnIH expression, which is upregulated in regressed testes, leading to apoptotic changes, and downregulated in developed testes, causing apoptotic inhibition. It is concluded that specific phase relation of neural oscillations may modulate the local testicular GnRH-GnIH system and alter the apoptotic mechanism in quail testes. Moreover, these findings highlight the physiological effects of time-dependent drug delivery, including the specific time intervals between two drugs.

2'-Hydroxyflavanone ameliorates mesenteric angiogenesis and portal-systemic collaterals in rats with liver fibrosis

BACKGROUND AND AIM

Portal-systemic collaterals lead to dreadful consequences in patients with cirrhosis. Angiogenesis participates in the development of liver fibrosis, hyperdynamic circulation, and portal-systemic collaterals. 2'-Hydroxyflavanone (2'-HF), one of the citrus fruits flavonoids, is known to have antiangiogenesis effect without adverse response. However, the relevant effects in liver fibrosis have not been surveyed.

METHODS

Male Wistar rats received thioacetamide (TAA, 100 mg/kg tiw, i.p.) for 6 weeks to induce liver fibrosis. On the 29th to 42nd day, rats randomly received 2'-HF (100 mg/kg, qod, i.p.) or vehicle (corn oil). On the 43rd day, after hemodynamic measurements, the followings were surveyed: (i) severity of collaterals; (ii) mesenteric angiogenesis; (iii) mesenteric proangiogenic factors protein expressions; (iv) Mesenteric vascular endothelial cells apoptosis; and (v) Mesenteric expressions of proteins regulating apoptosis.

RESULTS

Compared with the vehicle group, 2'-HF did not significantly change body weight, mean arterial pressure, heart rate, and portal pressure in TAA rats. 2'-HF significantly alleviated the severity of collaterals, but the mesenteric phospho-ERK, ERK, phospho-Akt, Akt, COX1, COX2, VEGF, and VEGFR-2 protein expressions were not altered. The apoptotic index of 2'-HF group was significantly higher and the mesenteric protein expressions of pro-apoptotic factors, NFkB 50, NFkB 65, Bax, phospho-p53, 17 kD cleaved caspase 3, and 17 kD casepase 3 were up-regulated.

CONCLUSIONS

2'-HF does not influence the hemodynamics but alleviated the severity of collaterals in rats with liver fibrosis and early portal hypertension. This is, at least partly, attributed to enhanced apoptosis of mesenteric vascular endothelial cells.

Molecular Basis and Consequences of the Cytochrome c-tRNA Interaction

The intrinsic apoptosis pathway occurs through the release of mitochondrial cytochrome c to the cytosol, where it promotes activation of the caspase family of proteases. The observation that tRNA binds to cytochrome c revealed a previously unexpected mode of apoptotic regulation. However, the molecular characteristics of this interaction, and its impact on each interaction partner, are not well understood. Using a novel fluorescence assay, we show here that cytochrome c binds to tRNA with an affinity comparable with other tRNA-protein binding interactions and with a molecular ratio of ∼3:1. Cytochrome c recognizes the tertiary structural features of tRNA, particularly in the core region. This binding is independent of the charging state of tRNA but is regulated by the redox state of cytochrome c. Compared with reduced cytochrome c, oxidized cytochrome c binds to tRNA with a weaker affinity, which correlates with its stronger pro-apoptotic activity. tRNA binding both facilitates cytochrome c reduction and inhibits the peroxidase activity of cytochrome c, which is involved in its release from mitochondria. Together, these findings provide new insights into the cytochrome c-tRNA interaction and apoptotic regulation.

Multifunctional murrel caspase 1, 2, 3, 8 and 9: Conservation, uniqueness and their pathogen-induced expression pattern

Caspases are evolutionarily conserved proteases which play fundamental role in apoptosis. Invasion of pathogen triggers the activation of caspases-mediated pro-inflammatory and pro-apoptotic pathways, where multifunctional caspases are involved. In striped murrel Channa striatus, epizootic ulcerative syndrome (EUS) causes endemics resulting in huge economic loss. Aphanomyces invadans, an oomycete is the primary causative agent of EUS which further induces secondary bacterial infections especially Aeromonas hydrophila. In order to get insights into the caspase gene family in C. striatus during EUS infection, we performed various physicochemical and structural analyses on the cDNA and protein sequences of five different murrel caspases namely CsCasp 1, 2, 3, 8 and 9. Sequence analysis of murrel caspase proteins showed that in spite of the conserved CASC domain, each caspase embraces some unique features which made them functionally different. Tissue distribution analysis showed that all the murrel caspases are highly expressed in one of the immune organs such as liver, kidney, spleen and blood cells. Further, to understand the role of caspase during EUS infection, modulation in expression of each caspase gene was analysed after inducing fungal and bacterial infection in C. striatus. Pathogen-induced gene expression pattern revealed an interesting fact that the expression of all the caspase genes reached a maximum level at 24 h post-infection (p.i) in case of bacteria, whereas it was 48 h in fungus. However, the initiation of elevated expression differed between each caspase based on their role such as pro-inflammatory, initiator and executioner caspase. Overall, the results suggested that the caspases in murrel are diverse in their structure and function. Here, we discuss the similarities and differences of five different murrel caspases.

Gefitinib Synergizes with Irinotecan to Suppress Hepatocellular Carcinoma via Antagonizing Rad51-Mediated DNA-Repair

Chemotherapy is the only choice for most of the advanced hepatocellular carcinoma (HCC) patients, while few agents were available, making it an urgent need to develop new chemotherapy strategies. A phase II clinical trial suggested that the efficacy of irinotecan in HCC was limited due to dose-dependent toxicities. Here, we found that gefitinib exhibited synergistic activity in combination with SN-38, an active metabolite of irinotecan, in HCC cell lines. And the enhanced apoptosis induced by gefitinib plus SN-38 was a result from caspase pathway activation. Mechanistically, gefitinib dramatically promoted the ubiquitin–proteasome-dependent degradation of Rad51 protein, suppressed the DNA repair, gave rise to more DNA damages, and ultimately resulted in the synergism of these two agents. In addition, the increased antitumor efficacy of gefitinib combined with irinotecan was further validated in a HepG2 xenograft mice model. Taken together, our data demonstrated for the first time that the combination of irinotecan and gefitinib showed potential benefit in HCC, which suggests that Rad51 is a promising target and provides a rationale for clinical trials investigating the efficacy of the combination of topoisomerase I inhibitors and gefitinib in HCC.