Apoptosis: molecular regulation of cell death

PIM kinase inhibitors: an updated patent review (2016-present)

INTRODUCTION

PIM Kinases (PIM-1, PIM-2, and PIM-3) have been reported to play crucial role in signaling cascades that govern cell survival, proliferation, and differentiation. Over-expression of these kinases leads to hematological malignancies such as diffuse large B cell lymphomas (DLBCL), multiple myeloma, leukemia, lymphoma and prostate cancer etc. PIM kinases as biomarkers and potential therapeutic targets have shown promise toward precision cancer therapy. The selective PIM-1, PIM-2, and/or PIM-3 isoform inhibitors have shown significant results in patients with advanced stages of cancer including relapsed/refractory cancer.

AREAS COVERED

A comprehensive literature review of PIM Kinases (PIM-1, PIM-2, and PIM-3) in oncogenesis, the patented PIM kinase inhibitors (2016-Present), and their pharmacological and structural insights have been highlighted.

EXPERT OPINION

Recently, PIM kinases viz. PIM-1, PIM-2, and PIM-3 (members of the serine/threonine protein kinase family) as therapeutic targets have attracted considerable interest in oncology especially in hematological malignancies. The patented PIM kinase inhibitors comprised of heterocyclic (fused)ring structure(s) like indole, pyridine, pyrazine, pyrazole, pyridazine, piperazine, thiazole, oxadiazole, quinoline, triazolo-pyridine, pyrazolo-pyridine, imidazo-pyridazine, oxadiazole-thione, pyrazolo-pyrimidine, triazolo-pyridazine, imidazo-pyridazine, pyrazolo-quinazoline and pyrazolo-pyridine etc. showed promising results in cancer chemotherapy.

Honokiol Prevents Intestinal Barrier Dysfunction in Mice with Severe Acute Pancreatitis and Inhibits JAK/STAT1 Pathway and Acetylation of HMGB1

OBJECTIVE

To investigate the effect of honokiol (HON) and the role of high-mobility group protein B1 (HMGB1) on the pathogenesis of severe acute pancreatitis (SAP).

METHODS

Thirty mice were numbered according to weight, and randomly divided into 5 groups using a random number table, including control, SAP, SAP and normal saline (SAP+NS), SAP and ethyl pyruvate (SAP+EP), or SAP+HON groups, 6 mice in each group. Samples of pancreas, intestine, and blood were collected 12 h after SAP model induction for examination of pathologic changes, immune function alterations by enzyme linked immunosorbent assay (ELISA), and Western blot. In vitro experiments, macrophages were divided into 5 groups, the control, lipopolysaccharide (LPS), LPS+DMSO (DMSO), LPS+anti-HMGB1 monoclonal antibody (mAb), and LPS+ HON groups. The tight connection level was determined by transmission electron microscopy and fluorescein isothiocyanate-labeled. The location and acetylation of HMGB1 were measured by Western blot. Finally, pyridone 6 and silencing signal transducer and activator of the transcription 1 (siSTAT1) combined with honokiol were added to determine whether the Janus kinase (JAK)/ STAT1 participated in the regulation of honokiol on HMGB1. The protein expression levels of HMGB1, JAK, and STAT1 were detected using Western blot.

RESULTS

Mice with SAP had inflammatory injury in the pancreas, bleeding of intestinal tissues, and cells with disrupted histology. Mice in the SAP+HON group had significantly fewer pathological changes. Mice with SAP also had significant increases in the serum levels of amylase, lipase, HMGB1, tumor necrosis factor- α, interleukin-6, diamine oxidase, endotoxin-1, and procalcitonin. Mice in the SAP+HON group did not show these abnormalities (P<0.01). Studies of Caco-2 cells indicated that LPS increased the levels of occludin and claudin-1 as well as tight junction permeability, decreased the levels of junctional adhesion molecule C, and elevated intercellular permeability (P<0.01). HON treatment blocked these effects. Studies of macrophages indicated that LPS led to low nuclear levels of HMGB1, however, HON treatment increased the nuclear level of HMGB1 (P<0.01). HON treatment also inhibited the expressions of JAK1, JAK2, and STAT1 (P<0.01) and increased the acetylation of HMGB1 (P<0.05).

CONCLUSION

HON prevented intestinal barrier dysfunction in SAP by inhibiting HMGB1 acetylation and JAK/STAT1 pathway.

Role of autophagy and proteostasis in neurodegenerative diseases: Exploring the therapeutic interventions

Neurodegenerative disorders are devastating disorders characterized by gradual loss of neurons and cognition or mobility impairment. The common pathological features of these diseases are associated with the accumulation of misfolded or aggregation of proteins. The pivotal roles of autophagy and proteostasis in maintaining cellular health and preventing the accumulation of misfolded proteins, which are associated with neurodegenerative diseases like Huntington's disease (HD), Alzheimer's disease (AD), and Parkinson's disease (PD). This article presents an in-depth examination of the interplay between autophagy and proteostasis, highlighting how these processes cooperatively contribute to cellular homeostasis and prevent pathogenic protein aggregate accumulation. Furthermore, the review emphasises the potential therapeutic implications of targeting autophagy and proteostasis to mitigate neurodegenerative diseases. While advancements in research hold promise for developing novel treatments, the article also addresses the challenges and complexities associated with modulating these intricate cellular pathways. Ultimately, advancing understanding of the underlying mechanism of autophagy and proteostasis in neurodegenerative disorders provides valuable insights into potential therapeutic avenues and future research directions.

Cell-free DNA diagnostics in transplantation utilizing next generation sequencing

The use of Next Generation Sequencing (NGS) to interrogate cell-free DNA (cfDNA) as a transplant diagnostic provides a crucial step in improving the accuracy of post-transplant monitoring of allograft health. cfDNA interrogation provides a powerful, yet minimally invasive, biomarker for disease and tissue injury. cfDNA can be isolated from a variety of body fluids and analyzed using bioinformatics to unlock its origins. Furthermore, cfDNA characteristics can reveal the mechanisms and conditions under which it was generated and released. In transplantation, donor-derived cfDNA monitoring provides a tool for identifying active allograft injury at the time of transplant, infection, and rejection. Multiple detection and interrogation methods for cfDNA detection are now being evaluated for clinical validity and hold the promise to provide minimally invasive, quantitative, and reproducible measures of allograft injury across organ types.

Post-translational modification and protein sorting to small extracellular vesicles including exosomes by ubiquitin and UBLs

Exosomes, a type of small extracellular vesicles (sEVs), are secreted membrane vesicles that are derived from various cell types, including cancer cells, mesenchymal stem cells, and immune cells via multivesicular bodies (MVBs). These sEVs contain RNAs (mRNA, miRNA, lncRNA, and rRNA), lipids, DNA, proteins, and metabolites, all of which mediate cell-to-cell communication. This communication is known to be implicated in a diverse set of diseases such as cancers and their metastases and degenerative diseases. The molecular mechanisms, by which proteins are modified and sorted to sEVs, are not fully understood. Various cellular processes, including degradation, transcription, DNA repair, cell cycle, signal transduction, and autophagy, are known to be associated with ubiquitin and ubiquitin-like proteins (UBLs). Recent studies have revealed that ubiquitin and UBLs also regulate MVBs and protein sorting to sEVs. Ubiquitin-like 3 (UBL3)/membrane-anchored Ub-fold protein (MUB) acts as a post-translational modification (PTM) factor to regulate efficient protein sorting to sEVs. In this review, we focus on the mechanism of PTM by ubiquitin and UBLs and the pathway of protein sorting into sEVs and discuss the potential biological significance of these processes.

Honokiol Eliminates Glioma/Glioblastoma Stem Cell-Like Cells Via JAK-STAT3 Signaling and Inhibits Tumor Progression by Targeting Epidermal Growth Factor Receptor

Malignant gliomas are the most aggressive forms of brain tumors; whose metastasis and recurrence contribute to high rates of morbidity and mortality. Glioma stem cell-like cells are a subpopulation of tumor-initiating cells responsible for glioma tumorigenesis, metastasis, recurrence and resistance to therapy. Epidermal growth factor receptor (EGFR) has been reported to be dysregulated in most cancers, including gliomas and its functions are closely linked to initiating tumor metastasis and a very poor prognosis. In search for compounds that may reduce the tumorigenic potential of gliomas/glioblastomas honokiol attracted our attention. Honokiol, purified from the bark of traditional Chinese herbal medicine Magnolia species, is beneficial in vitro and in animal models via a variety of pharmacological effects, including anti-inflammatory, anti-angiogenetic, anti-arrhythmic and antioxidant activities, as well as anti-proliferative and proapoptotic effects in a wide range of human cancer cells. However, its effects on glioma cells are unknown. Here, we used different concentrations of honokiol in treating U251 and U-87 MG human glioma/glioblastoma cells in cell culture. Results showed that honokiol inhibited glioma cell viability and colony formation and promoted apoptosis. It also inhibited glioma cell migration/proliferation and invasion. In addition, honokiol promoted apoptosis and reduced Bcl-2 expression, accompanied by increase in Bax expression. Honokiol reduced expression of EGFR, CD133 and Nestin. Moreover, honokiol inhibited the activation of both AKT and ERK signaling pathways, increased active caspase-3 level and reduced phosphorylation of STAT3. U-87 MG xenografts in nude mice and in immunotolerant zebrafish yolk sac showed that honokiol inhibits tumor growth and metastasis. Altogether, results indicate that honokiol reduces tumorigenic potentials, suggesting hopes for honokiol to be useful in the clinical management of glioma/glioblastoma.

Eventual re-vitrification or storage in liquid nitrogen vapor does not jeopardize the practical handling and transport of vitrified pig embryos

This study aimed (1) to evaluate the in vitro post-warming survival of porcine embryos after re-vitrification and (2) to assess the efficacy of transport of embryos in dry shipper (DS) in maintaining the viability and quality of vitrified embryos for a 3-day period. Embryos at the compacted or cavitating morula (CCM) and unhatched blastocyst (UBL) stages were surgically obtained from weaned, crossbred sows. In the first experiment, more than 85% of the embryos survived an initial vitrification and warming and achieved comparable survival rates to those of their fresh counterparts. In contrast, those embryos subjected to a second vitrification and warming had clearly lower survival rates (60% and 64% for re-vitrified embryos from the CCM and UBL groups, respectively) compared to the survival rates of the initial vitrification and fresh control groups (P < 0.01). Hatching rates were similar in re-vitrified blastocysts derived from vitrified CCMs and fresh control groups (50.8% and 55.3%, respectively). However, differences (P < 0.01) in hatching rates were recorded in re-vitrified blastocysts derived from vitrified UBLs and fresh control blastocysts (14.7% and 90.0%, respectively). In the second experiment, vitrified embryos were stored in a liquid nitrogen tank for one month. Then, the straws containing the embryos were transferred to a DS (DS group) or to another liquid nitrogen tank (control group) for an additional three days. Embryos from the DS and control groups had similar survival and hatching rates, regardless of the embryonic stage considered. The DS storage of CCMs and UBLs did not affect their development after culturing, including total cell numbers, compared to the control, although their apoptotic index was slightly higher (P < 0.05), regardless of the developmental stage. In conclusion, although re-vitrification negatively affects embryo survival, this study demonstrated that >60% of vitrified embryos could be successfully re-vitrified and re-warmed. The present study also showed the effectiveness of the DS for the storage of vitrified porcine CCMs and UBLs for at least three 3 days.

Oxymatrine induces apoptosis and inhibits invasion in Gallbladder carcinoma via PTEN/PI3K/AKT pathway

Oxymatrine extracted from Sophora flavescens Ait as a natural polyphenolic phytochemical has been demonstrated to exhibit anti-tumor effects on various cancers, including Gallbladder carcinoma (GBC). However, its underlying mechanisms of function are largely unknown in GBC cells. The present study is conducted to investigate the anti-tumor effects and the underlying mechanisms of oxymatrine on GBC cells in vitro and in vivo. The results showed that oxymatrine inhibited cell viability, metastatic ability and induced cell apoptosis in dose-dependent manners. Furthermore, we found that the expression of p-AKT, MMP-2, MMP-9 and the ratio of Bcl-2/Bax were significantly down-regulated, while the expression of PTEN was up-regulated in GBC cells. In addition, pretreatment with a specific PI3K/AKT activator (IGF-1) significantly antagonized the oxymatrine-mediated inhibition of GBC-SD cells. Subsequently, our in vivo studies showed that administration of oxymatrine induced a significant dose-dependent decrease in tumor growth. In conclusion, these findings indicated that the inhibition of cells proliferation, migration, invasion and the induction of apoptosis in response to oxymatrine in GBC cells, may function through the suppression of PTEN/PI3K/AKT pathway, which was considered as the vital signaling pathway in regulating tumorigenesis. These results suggested that oxymatrine might be a novel effective candidate as chemotherapeutic agent against GBC.

Trimebutine Promotes Glioma Cell Apoptosis as a Potential Anti-tumor Agent

Gliomas are the most common primary brain tumors with a usually fatal malignancy. They are associated with a poor prognosis although multiple therapeutic options have been available. Trimebutine is one of the prokinetic agents and it has been mainly used for treatment of disorders of the gastrointestinal (GI) tract such as irritable bowel syndrome. However, its effects on glioma cells remain unknown. Here, we used various concentrations of trimebutine to treat SHG44, U251, and U-87 MG human glioma/glioblastoma cells. And combined experiments of MTT, colony formation assay, and wound healing assay, as well as western blot and immunofluorescence staining were used to evaluate the effects of trimebutine on glioma cells. The results demonstrated that trimebutine significantly inhibited cell viability and colony formation. A significant inhibition of glioma cell migration was also indicated by wound healing assay. In addition, trimebutine promoted cell apoptosis and induced Bcl-2 downregulation, accompanied with Bax upregulation. Both immunofluorescence staining and western blot results showed that trimebutine increased the level of active Caspase-3. Moreover, trimebutine reduced the activation of both AKT and ERK signaling pathways. In subcutaneous U-87 MG cell xenograft tumors in nude mice, trimebutine significantly inhibited tumor growth. More TUNEL-positive apoptotic cells in tumor sections were observed in trimebutine-treated mice when compared to the vehicle control. Reduced Bcl-2 and upregulated Bax, as well as perturbed p-AKT and p-ERK signaling pathways were also observed in trimebutine-treated xenograft tissues. Our combined data indicated that trimebutine may be potentially applied for the clinical management of glioma/glioblastoma.

Tauroursodeoxycholic acid enhances the development of porcine embryos derived from in vitro-matured oocytes and evaporatively dried spermatozoa

Evaporative drying (ED) is an alternative technique for long-term preservation of mammalian sperm, which does not require liquid nitrogen or freeze-drying equipment, but offers advantages for storage and shipping at ambient temperature and low cost. However, the development of zygotes generated from these sperms was poor. Here, we demonstrated that the supplementation of tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, during embryo culture improved the developmental competency of embryos derived from in vitro matured pig oocytes injected intracytoplasmically with boar ED spermatozoa by reducing the production of reactive oxygen species, the DNA degradation and fragmentation, and the expression of apoptosis-related gene Bax and Bak, and by increasing the transcription of anti-apoptosis gene Bcl-XL and Bcl-2. Furthermore, TUDCA treatment promoted the blastocyst quality manifested by the total cell numbers and the ratio of inner cell mass. Taken together, our data suggest that evaporative drying would be a potentially useful method for the routine preservation of boar sperm in combination with further optimization of subsequently embryo culture conditions.

Apigenin induces both intrinsic and extrinsic pathways of apoptosis in human colon carcinoma HCT-116 cells

Apigenin is one of the plant-originated flavones with anticancer activities. In this study, apigenin was assessed for its in vitro effects on a human colon carcinoma line (HCT‑116 cells) in terms of anti-proliferation, cell cycle progression arrest, apoptosis and intracellular reactive oxygen species (ROS) generation, and then outlined its possible apoptotic mechanism for the cells. Apigenin exerted cytotoxic effect on the cells via inhibiting cell growth in a dose-time-dependent manner and causing morphological changes, arrested cell cycle progression at G0/G1 phase, and decreased mitochondrial membrane potential of the treated cells. Apigenin increased respective ROS generation and Ca2+ release and thereby, caused ER stress in the treated cells. Apigenin shows apoptosis induction towards the cells, resulting in enhanced portion of apoptotic cells. A mechanism involved ROS generation and endoplasmic reticulum stress was outlined for the apigenin-mediated apoptosis via both intrinsic mitochondrial and extrinsic pathways, based on the assayed mRNA and protein expression levels in the cells. With this mechanism, apigenin resulted in the HCT-116 cells with enhanced intracellular ROS generation and Ca2+ release together with damaged mitochondrial membrane, and upregulated protein expression of CHOP, DR5, cleaved BID, Bax, cytochrome c, cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9, which triggered apoptosis of the cells.

Long non-coding RNA TUG1 promotes cell proliferation and metastasis in human breast cancer

BACKGROUND

Long non-coding RNAs (LncRNAs) utilize a wide variety of mechanisms to regulate RNAs or proteins on the transcriptional or post-transcriptional levels. Accumulating studies have identified numerous LncRNAs to exert critical effects on different physiological processes, genetic disorders, and human diseases.

MATERIALS AND METHODS

Both clinical tissues from breast cancer patients and cultured cells were used for the qRT-PCR analysis. Specific siRNAs were included to assess the roles of TUG1 with cell viability assay, transwell assay, and cell apoptosis assay, respectively.

RESULTS

The expression of TUG1 was enhanced in breast cancerous tissues and in highly invasive breast cancer cell lines and was associated with clinical variables, including tumor size, distant metastasis and TNM staging. Knockdown of TUG1 significantly slowed down cell proliferation, cell migration, and invasion in breast cancer cell lines MDA-MB-231 and MDA-MB-436. In addition, cell apoptotic rate was shown to increase upon siTUG1 treatment as evidenced by increases of the activities of caspase-3 and caspase-9.

CONCLUSION

The identification of TUG1 as a critical mediator of breast cancer progression implied that it might serve as a biomarker for the diagnosis and treatment of breast cancer in clinic.

Molecular cloning and characterization of four caspases members in Apostichopus japonicus

The caspase family representing aspartate-specific cysteine proteases have been demonstrated to possess key roles in apoptosis and immune response. We previously demonstrated that LPS challenged Apostichopus japonicus coelomocyte could significantly induced apoptosis in vitro. However, apoptosis related molecules were scarcely investigated in this economic species. In the present work, we cloned and characterized four members caspase family from A. japonicus (designated as Ajcaspase-2, Ajcaspase-3, Ajcaspase-6, and Ajcaspase-8, respectively) by RACE. Multiple sequence alignment and structural analysis revealed that all Ajcaspases contained the conservative CASC domain at C terminal, in which some unique features for each Ajcaspase made them different from each other. These specific domains together with phylogenetic analysis supported that all these four identified proteins belonged to novel members of apoptotic signaling pathway in sea cucumber. Tissue distribution analysis revealed that four Ajcaspase genes were constitutively expressed in all examined tissues. The expression of Ajcaspase-2 was tightly correlated with that of Ajcaspase-8 in each detected tissues. Ajcaspase-3 and Ajcaspase-6 transcripts were both highly expressed in immune tissue of coelomocytes. Furthermore, the Vibrio splendidus challenged sea cucumber coelomocytes could significantly up-regulate the mRNA expressions of four genes. The expression levels of Ajcaspase-2 and Ajcaspase-8 were relative earlier than those of Ajcaspase-6 and Ajcaspase-3, respectively, which could be inferred that Ajcapase-2 might directly modulate Ajcaspase-6, and Ajcaspase-8 initiate the expression of Ajcaspase-3. The induce expressions differed among each Ajcaspase depending upon their roles such as initiator or effector caspase. All our results demonstrated that four Ajcaspases present diversified functions in apoptotic cascade signaling pathway of sea cucumber under immune response.

Fragment Length of Circulating Tumor DNA

Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134–144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132–145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

During cell death, DNA that is not contained within a membrane (i.e., cell-free DNA) enters the circulation. Detecting cell-free DNA originating from solid tumors (i.e., circulating tumor DNA, ctDNA), particularly solid tumors that have not metastasized, has proven challenging due to the relatively abundant background of normally occurring cell-free DNA derived from healthy cells. Our study defines the subtle but distinct differences in fragment length between normal cell-free DNA and ctDNA from a variety of solid tumors. Specifically, ctDNA was overall consistently shorter than the fragment length of normal cell-free DNA. Subsequently, we showed that a size-selection for shorter cell-free DNA fragments increased the proportion of ctDNA within a sample. These results provide compelling evidence that development of techniques to isolate a subset of cell-free DNA consistent with the ctDNA fragment lengths described in our study may substantially improve detection of non-metastatic solid tumors. As such, our findings may have a direct impact on the clinical utility of ctDNA for the non-invasive detection and diagnosis of solid tumors (i.e., the “liquid biopsy”), monitoring tumor recurrence, and evaluating tumor response to therapy.

Apoptosis Study in Thymic Involution in Tumour-Bearing Mice

By using a colorectal carcinoma induced by s.c. injection of 1,2-dimethylhydrazine and a transplantable fibrosarcoma developed in inbred BALB/c mice 6–8 weeks old we found that tumour development was accompanied by a remarkable thymic involution.

Mice bearing small fibrosarcoma or carcinoma (0,05 cm3) had thymuses and spleens with the same weight as those of normal mice. Thymic atrophy and splenomegalia developed in mice bearing large fibrosarcoma (5,00 cm3) and large carcinoma (0,20 cm3). Thymic involution was not the result of an increase in spontaneous cellular apoptosis. However, an increased susceptibility to apoptosis induced by etoposide was observed in thymocytes from mice bearing large carcinomas or large fibrosarcomas, as compared to the same cells derived from normal or small tumour-bearing mice. Dexamethasone induced comparable levels of apoptosis in thymocytes from all groups (normal mice, mice bearing small and large carcinoma and mice bearing small and large fibrosarcoma); doxorrubicin had no significant effect in any group.

Toxic Diatom Aldehydes Affect Defence Gene Networks in Sea Urchins

Marine organisms possess a series of cellular strategies to counteract the negative effects of toxic compounds, including the massive reorganization of gene expression networks. Here we report the modulated dose-dependent response of activated genes by diatom polyunsaturated aldehydes (PUAs) in the sea urchin Paracentrotus lividus. PUAs are secondary metabolites deriving from the oxidation of fatty acids, inducing deleterious effects on the reproduction and development of planktonic and benthic organisms that feed on these unicellular algae and with anti-cancer activity. Our previous results showed that PUAs target several genes, implicated in different functional processes in this sea urchin. Using interactomic Ingenuity Pathway Analysis we now show that the genes targeted by PUAs are correlated with four HUB genes, NF-κB, p53, δ-2-catenin and HIF1A, which have not been previously reported for P. lividus. We propose a working model describing hypothetical pathways potentially involved in toxic aldehyde stress response in sea urchins. This represents the first report on gene networks affected by PUAs, opening new perspectives in understanding the cellular mechanisms underlying the response of benthic organisms to diatom exposure.

The complexity of apoptotic cell death in mollusks: An update

Apoptosis is a type of programmed cell death that produces changes in cell morphology and in biochemical intracellular processes without inflammatory reactions. The components of the apoptotic pathways are conserved throughout evolution. Caspases are key molecules involved in the transduction of the death signal and are responsible for many of the biochemical and morphological changes associated with apoptosis. Nowadays, It is known that caspases are activated through two major apoptotic pathways (the extrinsic or death receptor pathway and the intrinsic or mitochondrial pathway), but there are also evidences of at least other alternative pathway (the perforin/granzyme pathway). Apoptosis in mollusks seems to be similar in complexity to apoptosis in vertebrates but also has unique features maybe related to their recurrent exposure to environmental changes, pollutants, pathogens and also related to the sedentary nature of some stages in the life cycle of mollusks bivalves and gastropods. As in other animals, apoptotic process is involved in the maintenance of tissue homeostasis and also constitutes an important immune response that can be triggered by a variety of stimuli, including cytokines, hormones, toxic insults, viruses, and protozoan parasites. The main goal of this work is to present the current knowledge of the molecular mechanisms of apoptosis in mollusks and to highlight those steps that need further study.

Quercetin promotes cell apoptosis and inhibits the expression of MMP-9 and fibronectin via the AKT and ERK signalling pathways in human glioma cells

Gliomas are the most common and malignant primary brain tumours and are associated with a poor prognosis despite the availability of multiple therapeutic options. Quercetin, a traditional Chinese medicinal herb, is an important flavonoid and has anti-cancer activity. Here, we evaluated whether quercetin could inhibit glioma cell viability and migration and promote apoptosis. The treatment of U87-MG glioblastoma and U251 and SHG44 glioma cell lines with different concentrations of quercetin inhibited cell viability in a dose-dependent manner. Wound healing assays indicated that quercetin significantly decreased glioma cell migration. β-galactosidase staining, DNA staining and Annexin V-EGF/PI double staining assays demonstrated that quercetin promoted cell senescence and apoptosis. In addition, the protein levels of p-AKT, p-ERK, Bcl-2, matrix metallopeptidase 9 (MMP-9) and fibronectin (FN) were significantly reduced following quercetin treatment. Therefore, we conclude that quercetin might inhibit the viability and migration and promote the senescence and apoptosis of glioma cells by suppressing the Ras/MAPK/ERK and PI3K/AKT signalling pathways. Quercetin might be a potential candidate for the clinical treatment of glioma.

Glutathione and cysteine enhance porcine preimplantation embryo development in vitro after intracytoplasmic sperm injection

Because intracytoplasmic sperm injection (ICSI) had been introduced to animal science, not only reproductive biology of domestic animals, but also medicine to treat infertility has been developed. This assisted reproductive technology is beneficial for generating transgenic animals, especially pigs, because polyspermy is the greatest hurdle in porcine IVF when researchers make highly qualified preimplantation embryos. However, ICSI-derived embryos expressed high level of reactive oxygen species (ROS), which are known to cause serious dysfunction during preimplantation development. The objective of this study was to investigate the developmental competence, ROS level, and apoptosis index when glutathione (GSH) or cysteine was supplemented into the in vitro culture medium for ICSI-derived porcine embryos. First, we evaluated the effect of different concentrations of GSH or cysteine on developmental ability of porcine ICSI-derived embryos. The cleavage rate (79.6%) and the blastocyst formation rate (20.9%) were significantly improved in culture medium supplemented with 1 mmol/L GSH compared with other concentrations or no supplementation. Also, 1.71 mmol/L cysteine showed a significantly higher proportion of cleavage (80.7%) and blastocyst formation (22.5%) than other cysteine-supplemented groups. Next, we confirmed that intracellular ROS level was significantly reduced in the group of blastocysts cultured with GSH or cysteine after ICSI compared with the no supplementation group. Finally, we found that terminal uridine nick-end labeling index, fragmentation, and total apoptosis were significantly decreased and the total cell number was significantly increased in blastocysts when ICSI-derived embryos were cultured with supplementation of 1.71 mmol/L cysteine or 1 mmol/L GSH. Taken together, these results strongly indicate that GSH or cysteine can improve the developmental competence of porcine ICSI-derived embryos by reducing intracellular ROS level and the apoptosis index.

Induction of apoptosis in MCF-7 cells by the hemagglutinin-neuraminidase glycoprotein of Newcastle disease virus Malaysian strain AF2240

Newcastle disease virus (NDV) exerts its naturally occurring oncolysis possibly through the induction of apoptosis. We hypothesized that the binding of the virus to the cell via the hemagglutinin-neuraminidase (HN) glycoprotein may be sufficient to not only induce apoptosis but to induce a higher apoptosis level than the parental NDV AF2240 virus. NDV AF2240 induction of apoptosis in MCF-7 human breast cancer cells was analyzed and quantified. In addition, the complete HN gene of NDV strain AF2240 was amplified, sequenced and cloned into the pDisplay eukaryotic expression vector. HN gene expression was first detected at the cell surface membrane of the transfected MCF-7 cells. HN induction of apoptosis in transfected MCF-7 cells was analyzed and quantified. The expression of the HN gene alone was able to induce apoptosis in MCF-7 cells but it was a less potent apoptosis inducer compared to the parental NDV AF2240 strain. In conclusion, the NDV AF2240 strain is a more suitable antitumor candidate agent than its recombinant HN gene unless the latter is further improved by additional modifications.

The TIMP-1 expression in germinal centers of hypertrophied adenoids in children

OBJECTIVES

The main aim of this study was to evaluate TIMP-1 expression in germinal centers of hypertrophied adenoids in children on the assumption that it can be treated as a marker of adenoidal tissue function.

PATIENTS AND METHODS

The study involved 54 children undergoing adenoidectomy; divided into three age groups: aged up to 5 years (8 children), 5-10 years (31 children) and over 10 years (15 children). The analyzed material was adenoids removed on the ground of hypertrophy, which caused obstructive symptoms and/or otitis media with effusion onset. Immunohistochemical analyses were carried out using monoclonal mouse antibody (Ab) (Novocastra) directed against human TIMP-1 protein. The presence of TIMP-1 positive lymphocytes within germinal centers and TIMP-1 immunostaining were scored.

RESULTS

The immunohistochemical staining showed the TIMP-1 positive lymphocytes mainly within the mantle zone. There was no statistically significant difference between the mean age of children for TIMP-1 immunoreaction levels. We have not found statistical correlation between the TIMP-1 staining and the clinical status of patients.

CONCLUSION

It is difficult to interpret our results. Our findings did not demonstrate changes in TIMP-1 expression according to age. This may indicate that the processes of hyperplasia, hypertrophy and atrophy of adenoid are not influenced by age and support our thesis that adenoid involution is rather the effect of changes in the number of lymphoid follicles that changes in them. However there is a need for further observational studies of TIMPs and MMPs in adenoid tissue.

Renal podocyte injury in a rat model of type 2 diabetes is prevented by metformin

Hyperglycemia promotes oxidative stress and hence generation of reactive oxygen species (ROS), which is known to play a crucial role in the pathogenesis of diabetic nephropathy. Metformin, an oral hypoglycemic drug, possesses antioxidant effects. The aim of this paper is to investigate the protective effects of metformin on the injury of renal podocytes in spontaneously diabetic Torii (SDT) rats, a new model for nonobese type 2 diabetes. Metformin (350 mg/kg/day) was given to SDT rats for 17 weeks. Blood glucose, glycated haemoglobin (HbA1c), and albuminuria were examined. Kidney histopathology, renal 8-hydroxydeoxyguanosine (8-OHdG) levels and apoptosis were examined. In 43-week-old SDT rats, severe hyperglycemia was developed, and albuminuria was markedly increased. Diabetes induced significant alterations in renal glomerular structure. In addition, urinary and renal 8-OHdG levels were highly increased, and podocyte loss was shown through application of the TUNEL and synaptopodin staining. However, treatment of SDT rats with metformin restored all these renal changes. Our data suggested that diabetes-induced podocyte loss in diabetic nephropathy could be suppressed by the antidiabetes drug, metformin, through the repression of oxidative injury.

In vivo Comparative Studies on Antigenotoxicity of Date Palm (Phoenix Dactylifera L.) Pits Extract Against DNA Damage Induced by N-Nitroso-N-methylurea in Mice

Aqueous extract of the date palm (Phoenix dactylifera L.) pits was prepared and its antigenotoxic activity was evaluated against N-Nitroso-N-methylurea (NMU) induced mutagenic effect in mice, using chromosome aberration (CA), micronuclei (MN) and DNA fragmentation assays as experimental end points in male mice. Date pits extract (DPE) was given orally to mice at the dose 25 mg/25 g mouse for successive five days in a week up to four consecutive weeks. NMU was used as mutagen and was given intraperitoneal (i.p) injection at single dose 80 mg/kg b.w., 24 hr after last dose of DPE in pre-treatment regimen and 24 hr before the first dose of DPE in the post-treatment regimen. Mice were scarified after one, two and seven days after the end of treatment. The results have shown that pre-and post-treatment regimens of DPE were significantly restored the DNA damage induced by NMU, as revealed by lowering of the occurrence of CAs and MN in bone marrow cells and inhibition of hepatic DNA fragmentation. These findings suggested that DPE produced their inhibitory activity either by desmutagenic or bioantimutagenic manner in pre-and post-treatment regimens respectively.

Aqueous Extract of Phyllanthus urinaria Induces Apoptosis in Human Cancer Cells

Cell apoptosis is now known to play an important role in the maintenance of cellular homeostasis and anti-carcinogenesis. The anticancer effect of aqueous extract prepared from Phyllanthus urinaria (P. urinaria) was investigated by analyzing its potential to induce apoptosis in human cancer cells. We showed that the aqueous extract of P. urinaria could reduce the viability by inducing the apoptosis in human cancer cells derived from several different origins as demonstrated by morphological changes and DNA fragmentation. Yet, P. urinaria extract exhibited no cytotoxic effect on normal human cells, including vascular endothelial cells and liver cells under the same conditions. It suggests that the aqueous extract of P. urinaria is substantially useful in treating various kinds of human cancer cells without toxic side effect on normal cells.

Losartan inhibits STAT1 activation and protects human glomerular mesangial cells from angiotensin II induced premature senescence

Human glomerular mesangial cells (HMCs) have a finite lifespan, and eventually enter irreversible growth arrest known as cellular senescence, which is thought to contribute to kidney ageing and age-related kidney disorders, such as chronic kidney disease. The signal transducer and activator of transcription 1 (STAT1) is a latent transcription factor involved in a variety of signal transduction pathways, including cell proliferation, apoptosis, and differentiation, but whether it could regulate HMC senescence still remains to be explored. In our study, the induction of angiotensin II (Ang II)-accelerated HMC senescence, as judged by increased senescence-associated β-galactosidase (SA-β-gal)-positive staining cells, morphological changes, and G0/G1 cell cycle arrest. STAT1 activity and the expression of p53 and p21Cip1 were increased after Ang II treatment. STAT1 knockdown using RNA interference significantly inhibited the progression of HMC senescence and decreased the elevated expression of p53 and p21Cip1. Pretreating HMCs with Ang II receptor blocker losartan also inhibited the progression of HMC senescence and STAT1 activity. Our results indicate that STAT1 is implicated in the mediation of Ang II-induced HMC senescence through p53/ p21Cip1 pathway, and that losartan could attenuate HMC senescence by regulating STAT1. The antioxidant N-acetyl-L-cysteine reduced ROS production and STAT1 activity induced by Ang II, indicating that Ang II uses ROS as a second messenger to regulate STAT1 activity.

Effects of matrine on proliferation and apoptosis in gallbladder carcinoma cells (GBC-SD)

Although matrine, a primary active component of dried Sophora flavescens root (ku shen), is known to induce apoptosis in a variety of tumor cells in vitro, the molecular mechanism of such apoptosis remains elusive. This analysis of the cell cycle and apoptosis in matrine-treated human gallbladder carcinoma cells (GBC-SD) showed that matrine can indeed inhibit cell proliferation and induce G1 cell cycle arrest and apoptosis in a dose- and time-dependent manner. An additional western blot analysis of matrine-treated cells also showed caspase-3 and Bcl-2 activation, as well as cyclinE down-regulation. Overall, the results indicate that matrine perturbs gallbladder cancer cell progression during the G1 phase by down-regulating cyclinE and induces apoptosis by decreasing the expression of the antiapoptotic protein Bcl-2 and increasing expression of the proapoptotic protein Bax.

A critical role for non-coding RNA GAS5 in growth arrest and rapamycin inhibition in human T-lymphocytes

Non-coding RNA GAS5 (growth arrest-specific transcript 5) is a 5'-TOP (5'-terminal oligopyrimidine tract) RNA, whose translation, and consequently also stability, is controlled by the mTOR (mammalian target of rapamycin) pathway. GAS5 was identified by functional expression cloning and is necessary and sufficient for normal growth arrest in both leukaemic and untransformed human T-lymphocytes. GAS5 is also required for the inhibitory effects of rapamycin and its analogues on T-cells. The striking functional effects of GAS5 may be mediated through the snoRNAs (small nucleolar RNAs) encoded in its introns and/or through the unusual folding of the mRNA itself, which sequesters, and therefore inhibits, the glucocorticoid receptor.

Anticancer activity of total flavonoids isolated from Xianhe Yanling Recipe (仙鹤延龄方)

OBJECTIVE

To investigate the anticancer activity of the total flavonoids isolated from a herbal formula, Xianhe Yanling Recipe (仙鹤延龄方), a recipe commonly used in cancer patients in China.

METHODS

The in vitro anticancer activity of the total flavonoids was determined using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on three cancer cell lines: MCF-7 (a human breast adenocarcinoma cell line), HepG-2 (a human hepatocellular carcinoma cell line) and ES-2 (a human ovarian cancer cell line). The in vivo anticancer effect of the total flavonoids was assessed in a mouse tumor model bearing H22-induced hepatocellular carcinoma, and cisplatin was used as a positive control.

RESULTS

The total flavonoids exerted a powerful inhibitory effect on the three cell lines, with 50% inhibiting concentrations (IC(50)) of 24.948, 31.569 and 6.923 μg/mL, respectively. In vivo studies showed that the total flavonoids had dose-dependent inhibitory effects on hepatocellular carcinoma in mice.

CONCLUSION

The total flavonoids from Xianhe Yanling Recipe have potential anticancer activity, and further researches and development are warranted.

New insights into the apoptotic process in mollusks: characterization of caspase genes in Mytilus galloprovincialis

Apoptosis is an essential biological process in the development and maintenance of immune system homeostasis. Caspase proteins constitute the core of the apoptotic machinery and can be categorized as either initiators or effectors of apoptosis. Although the genes encoding caspase proteins have been described in vertebrates and in almost all invertebrate phyla, there are few reports describing the initiator and executioner caspases or the modulation of their expression by different stimuli in different apoptotic pathways in bivalves. In the present work, we characterized two initiator and four executioner caspases in the mussel Mytilus galloprovincialis. Both initiators and executioners showed structural features that make them different from other caspase proteins already described. Evaluation of the genes’ tissue expression patterns revealed extremely high expression levels within the gland and gills, where the apoptotic process is highly active due to the clearance of damaged cells. Hemocytes also showed high expression values, probably due to of the role of apoptosis in the defense against pathogens. To understand the mechanisms of caspase gene regulation, hemocytes were treated with UV-light, environmental pollutants and pathogen-associated molecular patterns (PAMPs) and apoptosis was evaluated by microscopy, flow cytometry and qPCR techniques. Our results suggest that the apoptotic process could be tightly regulated in bivalve mollusks by overexpression/suppression of caspase genes; additionally, there is evidence of caspase-specific responses to pathogens and pollutants. The apoptotic process in mollusks has a similar complexity to that of vertebrates, but presents unique features that may be related to recurrent exposure to environmental changes, pollutants and pathogens imposed by their sedentary nature.

The release of high mobility group box 1 in apoptosis is triggered by nucleosomal DNA fragmentation

High mobility group box 1 (HMGB1) initially identified as a non-histone chromosomal protein, which mainly functions as chromatin structure and transcriptional regulation, has been recently reported to be secreted into extracellular milieu in necrosis and apoptosis, and act as a proinflammatory mediator. However, the mechanism by which apoptotic cells release HMGB1 is not clear. In this study, we found that staurosporine (apoptosis-inducer)-induced HMGB1 release was associated with nucleosomal DNA fragmentation catalyzed by caspase-activated DNase (CAD) in WEHI-231 cells. Importantly, this event was effectively attenuated by the treatment of a pan-caspase inhibitor, Z-VAD-fmk, and by the inhibition of CAD-mediated DNA fragmentation by the expression of caspase-resistant inhibitor of CAD (ICAD-CR). In WEHI-231/ICAD-CR and WEHI-231/Puro cells, DNase γ-catalyzed nucleosomal DNA fragmentation occurred by anti-IgM antibody treatment was critical for HMGB1 release. Furthermore, in DNase γ stably-expressing HeLa S3 cells (HeLa S3/γ), the release of HMGB1 accompanied with nucleosomal DNA fragmentation was more apparent than that in parental HeLa S3 cells in which DNA fragmentation was scarcely observed. Taken together, these date suggest that nucleosomal DNA fragmentation catalyzed by CAD or DNase γ plays a pivotal role in HMGB1 release.

Knockdown of growth-arrest-specific gene 7b (gas7b) using short-hairpin RNA desensitizes neuroblastoma cells to cisplatin: Implications for preventing apoptosis of neurons

Efficient control of cell survival and cell proliferation is critical for the development of neuron cells. Earlier, we observed that growth arrest-specific gene 7 (Gas7) plays a role in controlling neuritogenesis in mammals. In the present study, we report that the Gas7b isoform is involved in controlling growth arrest and apoptosis of neuroblastoma cells in response to various stimuli. Accordingly, knockdown of Gas7b using small-hairpin RNA (shRNA) was shown to reduce apoptosis induced either by serum starvation or by the antineoplastic agents cisplatin and nocodazole in human neuroblastoma SH-SY5Y cells. Gas7b knockdown also enhanced the ability of the treated cells to form clones in response to cisplatin. On the other hand, forced expression of Gas7a or Gas7b isoform in mouse neuroblastoma Neuro2A cells, which express a defective Gas7 gene, rendered the cells proapoptotic and vulnerable to cisplatin-induced apoptosis. In addition, Neuro2A cells that overexpressed Gas7 showed a reduced ability to form clones. Overexpression of Gas7 produced similar but less extensive effects in nonneuronal HEK293 cells. Taken together, our observations suggest that Gas7b is involved not only in neuritogenesis but also in the regulation of neuronal cell death.

Role of the urokinase plasminogen activator receptor in mediating impaired efferocytosis of anti-SSA/Ro-bound apoptotic cardiocytes: Implications in the pathogenesis of congenital heart block

RATIONALE

Binding of maternal anti-Ro/La antibodies to cognate antigen expressed on apoptotic cardiocytes decreases clearance by healthy cardiocytes, which may contribute to the development of autoimmune associated congenital heart block and fatal cardiomyopathy.

OBJECTIVE

Given recent evidence implicating the urokinase plasminogen activator receptor (uPAR) as a "don't eat me" signal during efferocytosis, experiments addressed whether surface bound anti-Ro antibodies inhibit apoptotic cell removal via an effect on the expression/function of the urokinase-type plasminogen activator protease uPA/uPAR system.

METHODS AND RESULTS

As assessed by flow cytometry and confocal microscopy, uPAR colocalizes and interacts with Ro60 on the surface of apoptotic human fetal cardiocytes. Blocking of uPAR enhances phagocytosis of apoptotic cardiocytes by healthy cardiocytes and reverses the anti-Ro60-dependent impaired clearance of apoptotic cardiocytes. Binding of anti-Ro60 antibodies to apoptotic cardiocytes results in increased uPAR expression, as well as enhanced uPA activity. The binding of anti-Ro60 did not alter other surface molecules involved in cell recognition (calreticulin, CD31, or CD47).

CONCLUSIONS

These data suggest that increased uPAR expression and uPA activity induced by anti-Ro60 binding to the apoptotic fetal cardiocyte provide a molecular basis by which these antibodies inhibit efferocytosis and ultimately lead to scar of the fetal conduction system and working myocardium.

Dose-response and relative biological effectiveness of fast neutrons: induction of apoptosis and inhibition of neurogenesis in the hippocampus of adult mice

PURPOSE

Our study compared the effects of high linear energy transfer (LET) fast neutrons on the induction of apoptosis and reduction of neurogenesis in the hippocampus of adult ICR mice with those of low-LET (60)Co gamma-rays, to evaluate the relative biological effectiveness (RBE) of fast neutrons in the adult hippocampal dentate gyrus (DG).

MATERIALS AND METHODS

The mice were exposed to 35 MeV fast neutrons or (60)Co gamma-rays. We evaluated acutely the incidence of apoptosis and expression of Ki-67 (a protein marker for cell proliferation originally defined by the monoclonal antibody Kiel-67) and doublecortin (DCX: an immature progenitor neuron marker) in the hippocampus after a single whole-body irradiation.

RESULTS

The number of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labelling (TUNEL)-positive apoptotic nuclei in the DG increased and both Ki-67- and DCX-positive cells declined in a dose-dependent pattern, with fast neutrons or gamma-rays. In the hippocampus, which showed an apoptosis frequency between 2 and 8 per DG, the RBE of fast neutrons was approximately 1.9. Additionally, the inhibitory effects of fast neutrons on the expression frequencies of Ki-67 (4-8) and DCX (8-32) were approximately 3.2 and 2.5 times, respectively, the effects of gamma-rays at the same dose.

CONCLUSIONS

Increased apoptotic cell death and decreased neurogenesis in the hippocampal DG were seen in a dose-dependent pattern after exposure to fast neutrons and gamma-rays. In addition, the different rate of hippocampal neurogenesis between different radiation qualities may be an index of RBE.

Apoptosis contributes to testicular toxicity induced by two isomers of bromopropanes

The aim of this study was to investigate the different testicular toxicity and the role of apoptosis in the possible mechanism induced by the two isomers of bromopropanes (BPs) in the same dosage. Following the 14-day treatment with a single dose of 1-BP and 2-BP (1 g/kg), male rats were killed and a series of experiments were performed. 1-BP and 2-BP both significantly decreased the epididymal sperm count, while only 2-BP induced an increase in sperms with abnormal heads. Morphological evaluation showed that 1-BP did not cause morphological changes in seminiferous epithelium, but 2-BP treatment resulted in the disappearance of spermatogonia, atrophy of the seminiferous tubules and degeneration of germ cells. 2-BP significantly increased the TUNEL-positive cells and the activation of caspase-3 and decreased the genes and proteins expression of Bax, Bcl-2 and p53. In contrast, there were no significant changes in the expression of apoptosis-related genes and proteins in 1-BP group, though the TUNEL-positive cells were significantly increased. Taken together, this study indicated that those two isomers both have toxicity in male rats, however, the testicular toxicity and the role of apoptosis in the toxic mechanism induced by 1-BP and 2-BP may be different.

Novel derivative of benzofuran induces cell death mostly by G2/M cell cycle arrest through p53-dependent pathway but partially by inhibition of NF-kappaB

The Dracaena resin is widely used in traditional medicine as an anticancer agent, and benzofuran lignan is the active component. In this report, we provide evidence that the synthetic derivative of benzofuran lignan (Benfur) showed antitumor activities. It induced apoptosis in p53-positive cells. Though it inhibited endotoxin-induced nuclear factor kappaB (NF-kappaB) activation in both p53-positive and -negative cells, the activation of caspase 3 was observed in p53-positive cells. It showed partial cell death effect in both p53-positive and -negative cells through inhibition of NF-kappaB. Cell cycle analysis using flow cytometry showed that treatment with this novel benozofuran lignan derivative to Jurkat T-cells, but not U-937 cells, resulted in a G2/M arrest in a dose- and time-dependent manner. It increased amounts of p21, p27, and cyclin B, but not phospho-Rb through p53 nuclear translocation in Jurkat T-cells, but not in U-937 cells. It inhibited amounts of MDM2 (murine double minute 2) by repressing the transcription factor Sp1, which was also proved in silico. It induced cell death in tumor cells, but not in primary T-cells. Overall, our data suggest that Benfur-mediated cell death is partially dependent upon NF-kappaB, but predominantly dependent on p53. Thus, this novel benzofuran lignan derivative can be effective chemopreventive or chemotherapeutic agent against malignant T-cells.