Structure-function analysis of Bcl-2 protein. Identification of conserved domains important for homodimerization with Bcl-2 and heterodimerization with Bax

Comparison of B-cell lymphoma 2 (BCL-2) expression in disordered proliferative endometrium and simple endometrial hyperplasia

BACKGROUND AND OBJECTIVE

B-cell lymphoma-2 (BCL-2) is an anti-apoptotic protein that may play a role in disordered proliferative endometrium (DPE) and endometrial hyperplasia (EH). Several studies have investigated BCL-2 expression in normal, hyperplastic endometrium and endometrial adenocarcinoma, with conflicting results. Therefore, the present study aimed to compare the expression of BCL-2 in disordered proliferative endometrium and simple EH.

METHODS

In this cross-sectional study, 63 DPE and 67 SEH samples from patients referred to Mostafa Khomeini Hospital between 2017 and 2022 were immunohistochemically stained by BCL-2 antibody. BCL-2 expression in each sample was reported as negative, weak positive, and strong positive. The findings were analyzed using SPSS version 16 software.

RESULTS

Negative, weakly positive, and strongly positive BCL-2 expression was observed in 55.6%, 38.1%, and 6.3% of DPE samples, and 61.2%, 31.3%, and 7.5% of SEH samples, respectively, which does not show a statistically significant difference (p=0.718). There was no relationship between the age of patients and BCL-2 expression in any of the two groups of DPE and SEH (p=0.378 and p=0.178, respectively).

CONCLUSION

BCL-2 expression is observed with a relatively similar frequency in DPE and SEH samples, and it is probably under the control of oestrogen hormone as the main factor involved in the pathogenesis of these lesions.

β3-Adrenergic receptor overexpression in cardiomyocytes preconditions mitochondria to withstand ischemia-reperfusion injury

β3-Adrenergic receptor (β3AR) agonists have been shown to protect against ischemia-reperfusion injury (IRI). Since β3ARs are present both in cardiomyocytes and in endothelial cells, the cellular compartment responsible for this protection has remained unknown. Using transgenic mice constitutively expressing the human β3AR (hβ3AR) in cardiomyocytes or in the endothelium on a genetic background of null endogenous β3AR expression, we show that only cardiomyocyte expression protects against IRI (45 min ischemia followed by reperfusion over 24 h). Infarct size was also limited after ischemia-reperfusion in mice with cardiomyocyte hβ3AR overexpression on top of endogenous β3AR expression. hβ3AR overexpression in these mice reduced IRI-induced cardiac fibrosis and improved long-term left ventricular systolic function. Cardiomyocyte-specific β3AR overexpression resulted in a baseline remodeling of the mitochondrial network, characterized by upregulated mitochondrial biogenesis and a downregulation of mitochondrial quality control (mitophagy), resulting in elevated numbers of small mitochondria with a depressed capacity for the generation of reactive oxygen species but improved capacity for ATP generation. These processes precondition cardiomyocyte mitochondria to be more resistant to IRI. Upon reperfusion, hearts with hβ3AR overexpression display a restoration in the mitochondrial quality control and a rapid activation of antioxidant responses. Strong protection against IRI was also observed in mice infected with an adeno-associated virus (AAV) encoding hβ3AR under a cardiomyocyte-specific promoter. These results confirm the translational potential of increased cardiomyocyte β3AR expression, achieved either naturally through exercise or artificially through gene therapy approaches, to precondition the cardiomyocyte mitochondrial network to withstand future insults.

Protein-based bandpass filters for controlling cellular signaling with chemical inputs

Biological signal processing is vital for cellular function. Similar to electronic circuits, cells process signals via integrated mechanisms. In electronics, bandpass filters transmit frequencies with defined ranges, but protein-based counterparts for controlled responses are lacking in engineered biological systems. Here, we rationally design protein-based, chemically responsive bandpass filters (CBPs) showing OFF-ON-OFF patterns that respond to chemical concentrations within a specific range and reject concentrations outside that range. Employing structure-based strategies, we designed a heterodimeric construct that dimerizes in response to low concentrations of a small molecule (ON), and dissociates at high concentrations of the same molecule (OFF). The CBPs have a multidomain architecture in which we used known drug receptors, a computationally designed protein binder and small-molecule inhibitors. This modular system allows fine-tuning for optimal performance in terms of bandwidth, response, cutoff and fold changes. The CBPs were used to regulate cell surface receptor signaling pathways to control cellular activities in engineered cells.

Selective vulnerability of hippocampal CA1 and CA3 pyramidal cells: What are possible pathomechanisms and should more attention be paid to the CA3 region in future studies?

Transient ischemia and reperfusion selectively damage neurons in brain, with hippocampal pyramidal cells being particularly vulnerable. Even within hippocampus, heterogeneous susceptibility is evident, with higher vulnerability of CA1 versus CA3 neurons described for several decades. Therefore, numerous studies have focused exclusively on CA1. Pediatric cardiac surgery is increasingly focusing on studies of hippocampal structures, and a negative impact of cardiopulmonary bypass on the hippocampus cannot be denied. Recent studies show a shift in selective vulnerability from neurons of CA1 to CA3. This review shows that cell damage is increased in CA3, sometimes stronger than in CA1, depending on several factors (method, species, age, observation period). Despite a highly variable pattern, several markers illustrate greater damage to CA3 neurons than previously assumed. Nevertheless, the underlying cellular mechanisms have not been fully deciphered to date. The complexity is reflected in possible pathomechanisms discussed here, with numerous factors (NMDA, kainate and AMPA receptors, intrinsic oxidative stress potential and various radicals, AKT isoforms, differences in vascular architecture, ratio of pro- and anti-apoptotic Bcl-2 factors, vulnerability of interneurons, mitochondrial dysregulation) contributing to either enhanced CA1 or CA3 vulnerability. Furthermore, differences in expressed genome, proteome, metabolome, and transcriptome in CA1 and CA3 appear to influence differential behavior after damaging stimuli, thus metabolomics-, transcriptomics-, and proteomics-based analyses represent a viable option to identify pathways of selective vulnerability in hippocampal neurons. These results emphasize that future studies should focus on the CA3 field in addition to CA1, especially with regard to improving therapeutic strategies after ischemic/hypoxic brain injury.

Molecular characterization and expression analysis of B-cell lymphoma-2 in Trachinotus ovatus and its role in apoptotic process

Introduction

B-cell lymphoma-2 (Bcl-2) is the first identified member of the Bcl-2 family that performs an anti-apoptotic function in mammals. However, its role in teleosts is not fully understood. In this study, Bcl-2 of Trachinotus ovatus (TroBcl2) was cloned, and its role in apoptosis was investigated.

Methods

In this study, Bcl-2 of Trachinotus ovatus (TroBcl2) was cloned by PCR. Quantitative real-time PCR (qRT-PCR) was used to detect its mRNA expression level in healthy condition and after LPS stimulation. Subcellular localization was performed by transfecting the pTroBcl2-N3 plasmid into golden pompano snout (GPS) cells and observed under an inverted fluorescence microscope DMi8 and further verified by immunoblotting. In vivo overexpression and RNAi knockdown method were performed to evaluate the role of TroBcl2 in apoptosis. The anti-apoptotic activity of TroBcl2 was detected by flow cytometry. The effect of TroBcl2 on the mitochondrial membrane potential (MMP) was measured by an enhanced mitochondrial membrane potential assay kit with JC-1. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was performed to evaluate the role of TroBcl2 in the DNA fragmentation. Immunoblotting was used to verify whether TroBcl2 inhibits the release of cytochrome c from mitochondria into the cytoplasm. The Caspase 3 and Caspase 9 Activity Assay Kits were used to investigate the effect of TroBcl2 on caspase 3 and caspase 9 activities. The effects of TroBcl2 on the expression of apoptosis-related and nuclear factor- κB (NF-κB) signaling pathway-related genes in vitro were evaluated by qRT-PCR and Enzyme linked immunosorbent assay (ELISA). Luciferase reporter assay was used to evaluate the activity in NF-κB signaling pathway.

Results and discussion

The full-length coding sequence of TroBcl2 contains 687 bp and encodes a protein containing 228 amino acids. Four conserved Bcl-2 homology (BH) domains and one invariant "NWGR" motif located in BH1 were identified in TroBcl2. In healthy T. ovatus, TroBcl2 was widely distributed in the eleven tested tissues, and higher expression levels were found in immune-related tissues, such as spleen and head kidney tissues. After stimulation with lipopolysaccharide (LPS), the expression of TroBcl2 in the head kidney, spleen, and liver was significantly upregulated. In addition, subcellular localization analysis revealed that TroBcl2 was localized in both the cytoplasm and nucleus. Functional experiments showed that TroBcl2 inhibited apoptosis, possibly by reducing mitochondrial membrane potential loss, decreasing DNA fragmentation, preventing cytochrome c release into cytoplasm, and reducing the caspase 3 and caspase 9 activations. Moreover, upon LPS stimulation, overexpression of TroBcl2 suppressed the activation of several apoptosis-related genes, such as BOK, caspase-9, caspase-7, caspase-3, cytochrome c, and p53. Furthermore, knockdown of TroBcl2 significantly increased the expression of those apoptosis-related genes. In addition, TroBcl2 overexpression or knockdown induced or inhibited, respectively, the transcription of NF-κB and regulated the expression of genes (such as NF-κB1 and c-Rel) in the NF-κB signaling pathway as well as the expression of the downstream inflammatory cytokine IL-1β. Overall, our study suggested that TroBcl2 performs its conserved anti-apoptotic function via the mitochondrial pathway and may serve as an anti-apoptotic regulator in T. ovatus.

Glycobiology of cellular expiry: Decrypting the role of glycan-lectin regulatory complex and therapeutic strategies focusing on cancer

Often the outer leaflets of living cells bear a coat of glycosylated proteins, which primarily regulates cellular processes. Glycosylation of such proteins occurs as part of their post-translational modification. Within the endoplasmic reticulum, glycosylation enables the attachment of specific oligosaccharide moieties such as, 'glycan' to the transmembrane receptor proteins which confers precise biological information for governing the cell fate. The nature and degree of glycosylation of cell surface receptors are regulated by a bunch of glycosyl transferases and glycosidases which fine-tune attachment or detachment of glycan moieties. In classical death receptors, upregulation of glycosylation by glycosyl transferases is capable of inducing cell death in T cells, tumor cells, etc. Thus, any deregulated alternation at surface glycosylation of these death receptors can result in life-threatening disorder like cancer. In addition, transmembrane glycoproteins and lectin receptors can transduce intracellular signals for cell death execution. Exogenous interaction of lectins with glycan containing death receptors signals for cell death initiation by modulating downstream signalings. Subsequently, endogenous glycan-lectin interplay aids in the customization and implementation of the cell death program. Lastly, the glycan-lectin recognition system dictates the removal of apoptotic cells by sending accurate signals to the extracellular milieu. Since glycosylation has proven to be a biomarker of cellular death and disease progression; glycans serve as specific therapeutic targets of cancers. In this context, we are reviewing the molecular mechanisms of the glycan-lectin regulatory network as an integral part of cell death machinery in cancer to target them for successful therapeutic and clinical approaches.

Tetracycline-controlled (TetON) gene expression system for the smut fungus Ustilago maydis

Ustilago maydis is a biotrophic phytopathogenic fungus that causes corn smut disease. As a well-established model system, U. maydis is genetically fully accessible with large omics datasets available and subject to various biological questions ranging from DNA-repair, RNA-transport, and protein secretion to disease biology. For many genetic approaches, tight control of transgene regulation is important. Here we established an optimised version of the Tetracycline-ON (TetON) system for U. maydis. We demonstrate the Tetracycline concentration-dependent expression of fluorescent protein transgenes and the system's suitability for the induced expression of the toxic protein BCL2 Associated X-1 (Bax1). The Golden Gate compatible vector system contains a native minimal promoter from the mating factor a-1 encoding gene, mfa with ten copies of the tet-regulated operator (tetO) and a codon optimised Tet-repressor (tetR*) which is translationally fused to the native transcriptional corepressor Mql1 (UMAG_05501). The metabolism-independent transcriptional regulator system is functional both, in liquid culture as well as on solid media in the presence of the inducer and can become a useful tool for toxin-antitoxin studies, identification of antifungal proteins, and to study functions of toxic gene products in Ustilago maydis.

Combined 4D-QSAR and target-based approaches for the determination of bioactive Isatin derivatives

The hybrid method of the Electron-Conformational Genetic Algorithm (EC-GA) was used to determine the pharmacophore groups and to estimate anticancer activity in isatin derivatives using a robust 4D-QSAR software (EMRE). To build the model, each compound is represented by a set of conformers rather than a single conformation. The Electron Conformational Matrix of Congruity (ECMC) is composed via EMRE software. Electron Conformational Submatrix of Activity (ECSA) was calculated by the comparison of these matrices. Genetic algorithm was used to select important variables to predict theoretical activity. The model with the best seven parameters produced satisfactory results. The E statistics technique was applied to the generated EC-GA model to evaluate the individual contribution of each of the descriptors on biological activity. The r² and q² values of the training set compounds were found to be 0.95 and 0.93, respectively. Because no previous 4D-QSAR studies on isatin derivatives have been conducted, this study is important in the development of new isatin derivatives. In this study, 27 isatin derivatives whose activities were estimated using the hybrid EC-GA method were also investigated through molecular docking and molecular dynamics simulations for their BCL-2 inhibitory activity.

TH1902, a new docetaxel-peptide conjugate for the treatment of sortilin-positive triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subgroup of cancers which lacks the expression and/or amplification of targetable biomarkers (ie, estrogen receptor, progestrogen receptor, and human epidermal growth factor receptor 2), and is often associated with the worse disease-specific outcomes than other breast cancer subtypes. Here, we report that high expression of the sortilin (SORT1) receptor correlates with the decreased survival in TNBC patients, and more importantly in those bearing lymph node metastases. By exploiting SORT1 function in ligand internalization, a new anticancer treatment strategy was designed to target SORT1-positive TNBC-derived cells both in vitro and in two in vivo tumor xenografts models. A peptide (TH19P01), which requires SORT1 for internalization and to which many anticancer drugs could be conjugated, was developed. In vitro, while the TH19P01 peptide itself did not exert any antiproliferative or apoptotic effects, the docetaxel-TH19P01 conjugate (TH1902) exerted potent antiproliferative and antimigratory activities when tested on TNBC-derived MDA-MB-231 cells. TH1902 triggered faster and more potent apoptotic cell death than did unconjugated docetaxel. The apoptotic and antimigratory effects of TH1902 were both reversed by two SORT1 ligands, neurotensin and progranulin, and on siRNA-mediated silencing of SORT1. TH1902 also altered microtubule polymerization and triggered the downregulation of the anti-apoptotic Bcl-xL biomarker. In vivo, both i.p. and i.v. administrations of TH1902 led to greater tumor regression in two MDA-MB-231 and HCC-70 murine xenograft models than did docetaxel, without inducing neutropenia. Altogether, the data demonstrates the high in vivo efficacy and safety of TH1902 against TNBC through a SORT1 receptor-mediated mechanism. This property allows for selective treatment of SORT1-positive TNBC and makes TH1902 a promising avenue for personalized therapy with the potential of improving the therapeutic window of cytotoxic anticancer drugs such as docetaxel.

A rational blueprint for the design of chemically-controlled protein switches

Small-molecule responsive protein switches are crucial components to control synthetic cellular activities. However, the repertoire of small-molecule protein switches is insufficient for many applications, including those in the translational spaces, where properties such as safety, immunogenicity, drug half-life, and drug side-effects are critical. Here, we present a computational protein design strategy to repurpose drug-inhibited protein-protein interactions as OFF- and ON-switches. The designed binders and drug-receptors form chemically-disruptable heterodimers (CDH) which dissociate in the presence of small molecules. To design ON-switches, we converted the CDHs into a multi-domain architecture which we refer to as activation by inhibitor release switches (AIR) that incorporate a rationally designed drug-insensitive receptor protein. CDHs and AIRs showed excellent performance as drug responsive switches to control combinations of synthetic circuits in mammalian cells. This approach effectively expands the chemical space and logic responses in living cells and provides a blueprint to develop new ON- and OFF-switches.

Small-molecule responsive protein switches are crucial components to control synthetic cellular activities. Here, we present a computational protein design strategy to repurpose drug-inhibited protein-protein interactions into OFF- and ON-switches active in cells.

B Cell Lymphoma 2: A Potential Therapeutic Target for Cancer Therapy

Defects in the apoptosis mechanism stimulate cancer cell growth and survival. B cell lymphoma 2 (Bcl-2) is an anti-apoptotic molecule that plays a central role in apoptosis. Bcl-2 is the founding constituent of the Bcl-2 protein family of apoptosis controllers, the primary apoptosis regulators linked with cancer. Bcl-2 has been identified as being over-expressed in several cancers. Bcl-2 is induced by protein kinases and several signaling molecules which stimulate cancer development. Identifying the important function played by Bcl-2 in cancer progression and development, and treatment made it a target related to therapy for multiple cancers. Among the various strategies that have been proposed to block Bcl-2, BH3-mimetics have appeared as a novel group of compounds thanks to their favorable effects on many cancers within several clinical settings. Because of the fundamental function of Bcl-2 in the regulation of apoptosis, the Bcl-2 protein is a potent target for the development of novel anti-tumor treatments. Bcl-2 inhibitors have been used against several cancers and provide a pre-clinical platform for testing novel therapeutic drugs. Clinical trials of multiple investigational agents targeting Bcl-2 are ongoing. This review discusses the role of Bcl-2 in cancer development; it could be exploited as a potential target for developing novel therapeutic strategies to combat various types of cancers. We further highlight the therapeutic activity of Bcl-2 inhibitors and their implications for the therapeutic management of cancer.

Contribution of Yeast Studies to the Understanding of BCL-2 Family Intracellular Trafficking

BCL-2 family members are major regulators of apoptotic cell death in mammals. They form an intricate regulatory network that ultimately regulates the release of apoptogenic factors from mitochondria to the cytosol. The ectopic expression of mammalian BCL-2 family members in the yeast Saccharomyces cerevisiae, which lacks BCL-2 homologs, has been long established as a useful addition to the available models to study their function and regulation. In yeast, individual proteins can be studied independently from the whole interaction network, thus providing insight into the molecular mechanisms underlying their function in a living context. Furthermore, one can take advantage of the powerful tools available in yeast to probe intracellular trafficking processes such as mitochondrial sorting and interactions/exchanges between mitochondria and other compartments, such as the endoplasmic reticulum that are largely conserved between yeast and mammals. Yeast molecular genetics thus allows the investigation of the role of these processes on the dynamic equilibrium of BCL-2 family members between mitochondria and extramitochondrial compartments. Here we propose a model of dynamic regulation of BCL-2 family member localization, based on available evidence from ectopic expression in yeast.

Classical swine fever virus Npro antagonises IRF3 to prevent IFN-independent TLR3 and RIG-I-mediated apoptosis

Classical swine fever virus (CSFV) is the causative agent of classical swine fever, a notifiable disease of economic importance that causes severe leukopenia, fever and haemorrhagic disease in domesticated pigs and wild boar across the globe. CSFV has been shown to antagonise the induction of type I IFN, partly through a function of its N-terminal protease (N^pro) which binds IRF3 and targets it for proteasomal degradation. Additionally, N^pro has been shown to antagonise apoptosis triggered by the dsRNA-homolog poly(I:C), however the exact mechanism by which this is achieved has not been fully elucidated. In this study we confirm the ability of N^pro to inhibit dsRNA-mediated apoptosis and show that N^pro is also able to antagonise Sendai virus-mediated apoptosis in PK-15 cells. Gene edited PK-15 cell lines were used to show the dsRNA-sensing pathogen recognition receptors (PRRs) TLR3 and RIG-I specifically respond to poly(I:C) and SeV respectively, subsequently triggering apoptosis through pathways that converge on IRF3 and culminate in the cleavage of caspase-3. Importantly, this IRF3-mediated apoptosis was found to be dependent on transcription-independent functions of IRF3 and also on Bax, a pro-apoptotic Bcl-2 family protein, through a direct interaction between the two proteins. Deletion of IRF3, stable expression of N^pro and infection with wild-type CSFV were found to antagonise the mitochondrial localisation of Bax, a key hallmark of the intrinsic, mitochondrial pathway of apoptosis. Together, these findings show that N^pro's putative interaction with IRF3 is involved not only in its antagonism of type I IFN, but also dsRNA-mediated mitochondrial apoptosis.Importance Responsible for severe haemorrhagic disease in domestic pigs and wild boar, classical swine fever is recognised by the World Organisation for Animal Health (OIE) and European Union as a notifiable disease of economic importance. Persistent infection, immunotolerance and early dissemination of the virus at local sites of infection have been linked to the antagonism of type I IFN induction by N^pro This protein may further contribute to these phenomena by antagonising the induction of dsRNA-mediated apoptosis. Ultimately, apoptosis is an important innate mechanism by which cells counter viruses at local sites of infection, thus preventing wider spread and dissemination within the host, potentially also contributing to the onset of persistence. Elucidation of the mechanism by which Npro antagonises the apoptotic response will help inform the development of rationally-designed live-attenuated vaccines and antivirals for control of outbreaks in typically CSFV-free countries.

Effect of intranasal instillation of Escherichia coli on apoptosis of spleen cells in diet-induced-obese mice

Splenic immune function was enhanced in diet-induced-obese (DIO) mice caused by Escherichia coli. The changes in spleen function on apoptosis were still unknown. Two hundred mice in groups Lean-E. coli and DIO-E. coli were intranasal instillation of E. coli. And another two hundred mice in groups Lean-PBS and DIO-PBS were given phosphate-buffered saline (PBS). Subsequently, spleen histology was analyzed. Then the rates of spleen cell (SC) apoptosis, and expression of the genes and proteins of Bcl-2, Bax, caspase-3 and caspase-9 were quantified in each group at 0 h (uninfected), 12 h, 24 h, and 72 h postinfection. The SC apoptosis rates of the DIO-E. coli groups were lower than those of the DIO-PBS groups at 12, 24 and 72 h (p < 0.05). Anti-apoptotic Bcl-2 expression gene and protein of the DIO-E. coli groups were higher than those of the DIO-PBS groups (p < 0.05). Gene expressions of pro-apoptotic Bax, caspase-3 and caspase-9 of the DIO-E. coli groups were lower than those of DIO-PBS groups at 12, 24 and 72 h (p < 0.05). The SC apoptosis rates of the Lean-E. coli groups were higher than those of the Lean- PBS groups at 12 h and 24 h (p < 0.05). Interestingly, the SC apoptosis rates in the DIO-E. coli groups were lower than those of the Lean-E. coli groups at 12 h (p < 0.05). In conclusion, our results suggested that the DIO mice presented stronger anti-apoptotic abilities than Lean mice in non-fatal acute pneumonia induced by E. coli infection, which is more conducive to protecting the spleen and improving the immune defense ability of the body.

Macroporous organosilicon nanocomposites co-deliver Bcl2-converting peptide and chemotherapeutic agent for synergistic treatment against multidrug resistant cancer

Therapeutic biomacromolecules are confronted with in vivo challenges of low bio-stability and poor tumor tissue-penetration. Herein, we report for the first time, our development and characterization of a hybrid nanocomposite for delivering a Bcl-2-converting peptide (NuBCP9, N9 hereafter) and testing its efficacy alone or together with doxorubicin (DOX). The hybrid nanocomposite is composed of the internal large pore sized-mesoporous silica nanoparticles (MSNs) and the external highly-branched polyamidoamine (PAMAM) dendrimers, into which N9 peptide and DOX were encapsulated for the different sub-cellular delivery to treat drug-resistant cancer. The nanocomposite possessed the particle and pore sizes of ~37 nm and ~8 nm, which displayed the superior tumor penetration capacity over naked MSNs both in cultured-3D tumor sphere and in live animal models. Moreover, the dual drug nanocomposite exhibited a great synergistic anticancer effect on Bcl-2-positive cancer cells in vitro and animals with the negligible toxic side effects. The tumor inhibition rate of the nanocomposite (89%) was five times as much as the two drugs combination. This design provides a new effective, safe and versatile strategy to fabricate large pore-sized MSNs with the organic-inorganic hybrid framework to concurrently transport therapeutic peptides and chemotherapeutics to the specific sub-cellular locations for the synergistic cancer therapy and drug resistance reversal, which has significant impact on the development of improved cancer therapeutics.

Decoding the sweet regulation of apoptosis: the role of glycosylation and galectins in apoptotic signaling pathways

Glycosylation and glycan-binding proteins such as galectins play an important role in the control of cell death signaling. Strikingly, very little attention has been given so far to the understanding of the molecular details behind this key regulatory network. Glycans attached to the death receptors such as CD95 and TRAIL-Rs, either alone or in a complex with galectins, might promote or inhibit apoptotic signals. However, we have just started to decode the functions of galectins in the modulation of extrinsic and intrinsic apoptosis. In this work, we have discussed the current understanding of the glycosylation-galectin regulatory network in CD95- as well as TRAIL-R-induced apoptosis and therapeutic strategies based on targeting galectins in cancer.

Synthesized Ceramide Induces Growth of Dermal Papilla Cells with Potential Contribution to Hair Growth

Background

The ceramide is known to play an important role in the formation of intracellular lipids, and play a crucial role as a barrier for skin and hair cuticle. Recent study has revealed that ceramide has potential effect on hair growth in a mouse model. However, the role of ceramide in human dermal papilla cells (hDPCs) known to play an important role in hair growth is not well understood yet.

Objective

The goal of this study was to investigate the effect of synthetic ceramides (oleyl and stearyl ceramides) on hair growth using hDPCs.

Methods

hDPCs were treated with synthesized ceramides. hDPCs viability was evaluated by MTT assay. The expression of hair growth related factors were investigated by western blot, real-time polymerase chain reaction and growth factor array. The expression of β-catenin was confirmed by immunofluorescence.

Results

Treatment with ceramides increased the expression of proteins affecting cell proliferation such as Bcl-2, BAX, phosphorylated-ERK and Cyclin D1. Also, ceramides treatment were increased the expression of several growth factors, including epidermal growth factor family, and promote the expression of Wnt/β-catenin and BMP2/4 signaling.

Conclusion

Our data suggest that synthetic ceramides stimulates hair growth by induction proliferation of hDPCs via modulation of Wnt/β-catenin and BMP2/4 signaling.

A Review on the Effect of Traditional Chinese Medicine Against Anthracycline-Induced Cardiac Toxicity

Anthracyclines are effective agents generally used to treat solid-tumor and hematologic malignancies. The use of anthracyclines for over 40 years has improved cancer survival statistics. Nevertheless, the clinical utility of anthracyclines is limited by its dose-dependent cardiotoxicity that adversely affects 10-30% of patients. Anthracycline-induced cardiotoxicity may be classified as acute/subacute or chronic/late toxicity and leads to devastating adverse effects resulting in poor quality of life, morbidity, and premature mortality. Traditional Chinese medicine has a history of over 2,000 years, involving both unique theories and substantial experience. Several studies have investigated the potential of natural products to decrease the cardiotoxic effects of chemotherapeutic agents on healthy cells, without negatively affecting their antineoplastic activity. This article discusses the mechanism of anthracycline-induced cardiotoxicity, and summarizes traditional Chinese medicine treatment for anthracycline-induced heart failure (HF), cardiac arrhythmia, cardiomyopathy, and myocardial ischemia in recent years, in order to provide a reference for the clinical prevention and treatment of cardiac toxicity.

A double point mutation at residues Ile14 and Val15 of Bcl-2 uncovers a role for the BH4 domain in both protein stability and function

B-cell lymphoma 2 (Bcl-2) protein is the archetype apoptosis suppressor protein. The N-terminal Bcl-2-homology 4 (BH4) domain of Bcl-2 is required for the antiapoptotic function of this protein at the mitochondria and endoplasmic reticulum (ER). The involvement of the BH4 domain in Bcl-2's antiapoptotic functions has been proposed based on Gly-based substitutions of the Ile14/Val15 amino acids, two hydrophobic residues located in the center of Bcl-2's BH4 domain. Following this strategy, we recently showed that a BH4-domain-derived peptide in which Ile14 and Val15 have been replaced by Gly residues, was unable to dampen proapoptotic Ca²⁺ -release events from the ER. Here, we investigated the impact of these mutations on the overall structure, stability, and function of full-length Bcl-2 as a regulator of Ca²⁺ signaling and cell death. Our results indicate that full-length Bcl-2 Ile14Gly/Val15Gly, in contrast to wild-type Bcl-2, (a) displayed severely reduced structural stability and a shortened protein half-life; (b) failed to interact with Bcl-2-associated X protein (BAX), to inhibit the inositol 1,4,5-trisphosphate receptor (IP₃ R) and to protect against Ca²⁺ -mediated apoptosis. We conclude that the hydrophobic face of Bcl-2's BH4 domain (Ile14, Val15) is an important structural regulatory element by affecting protein stability and turnover, thereby likely reducing Bcl-2's ability to modulate the function of its targets, like IP₃ R and BAX. Therefore, Bcl-2 structure/function studies require pre-emptive and reliable determination of protein stability upon introduction of point mutations at the level of the BH4 domain.

Application of non-invasive low strength pulsed electric field to EGCG treatment synergistically enhanced the inhibition effect on PANC-1 cells

Traditional therapies for pancreatic cancer are usually expensive and likely to cause side effects, and most patients have the risk of recurrence and suffering pain. Here, we investigated combination treatment of epigallocatechin-3-gallate (EGCG) and non-invasive low strength pulsed electric field (PEF) on the human pancreatic cell line PANC-1. Cells were cultured in various concentrations of EGCG and exposed to trains of PEF. The results showed that the low strength PEF alone or single treatment with low concentration of EGCG did not obviously affect the cell proliferation and migration in PANC-1. However, the EGCG-induced inhibitions of cell viability and migration ability in PANC-1 were dramatically enhanced by the further exposure of low strength PEF (60 V/cm). In particular, the same combination treatment caused less inhibition of cell viability in non-malignant HEK293 cells. We also found the combination treatment significantly decreased the ratio of Bcl-2/Bax protein and increased caspase activity in PANC-1 cells, resulting in the promotion of apoptotic responses, evidenced by chromatin condensation. The findings of the present study reveal the synergistic reactions in the combination treatment may severely disturb mitochondria, enhance the intrinsic pathway transduction, and effectively induce apoptosis; moreover, the migration and invasion of PANC-1 cancer cells were also significantly suppressed. Since normal cells are less sensitive to this combination treatment, and the non-invasive PEF could be modified to focus on a specific location, this treatment may serve as a promising method for anti-cancer therapy.

Cotton Leaf Curl Multan Betasatellite DNA as a Tool to Deliver and Express the Human B-Cell Lymphoma 2 (Bcl-2) Gene in Plants

The betasatellite DNA associated with Cotton leaf curl Multan virus (CLCuMB) contains a single complementary-sense ORF, βC1, which is a pathogenicity determinant. CLCuMB was able to replicate in plants in the presence of diverse helper geminiviruses, including Tomato leaf curl virus-Australia (TLCV-Au), Iranian isolate of Tomato yellow leaf curl virus (TYLCV-[Ab]), and Beet curly top virus (BCTV-Svr), and can be used as a plant gene delivery vector. To test the hypothesis that CLCuMB has the potential to act as an animal gene delivery vector, a specific insertion construct was produced by the introduction of a human B-cell lymphoma 2 (Bcl-2) cDNA into a mutant DNA of CLCuMB in which the βC1 was deleted (β∆C1). The recombinant βΔC1-Bcl-2 construct was successfully replicated in tomato and tobacco plants in the presence of TLCV-Au, BCTV-Svr and TYLCV-[Ab]. Real-time PCR and Western blot analyses of plants containing the replicative forms of recombinant βΔC1-Bcl-2 DNA showed that Bcl-2 gene was expressed in an acceptable level in these plants, indicating that β∆C1 can be used as a tool to deliver and express animal genes in plants. This CLCuMB-based system, having its own promoter activity, offers the possibility of production of animal recombinant proteins in plants.

Roles of plant hormones and anti-apoptosis genes during drought stress in rice (Oryza sativa L.)

We previously identified the rice (Oryza sativa) senescence-associated gene OsSAP which encodes a highly conserved protein involved in anti-apoptotic activity. This novel Bax suppressor-related gene regulates tolerance to multiple stresses in yeast. Here, we show the effects of drought stress on leaf and root tissues of plants over-expressing OsSAP in relation to the levels of phytohormones, abscisic acid (ABA), jasmonic acid (JA), indole-3-carboxylic acid (ICA), gibberellic acid (GA3), and zeatin. Results showed that rice plants over-expressing SAP were tolerant to drought stress compared to wild type and the plants over-expressing AtBI-1, which is a homolog of the human Bax inhibitor-1 in Arabidopsis. ABA and JA levels in OsSAP and AtBI-1 transgenic plants consistently increased up to at least 3 days after drought treatment, whereas lower GA3 levels were recorded during early drought period. Comparison between control and transgenic plants overexpressing anti-apoptosis genes OsSAP and AtBI-1 resulted in different patterns of hormone levels, indicating that these genes are involved in the plant responses to drought stress and present an opportunity for further study on drought stress tolerance in rice and other plant species.

Separation of glycine-rich proteins from sea hare eggs and their anti-cancer activity against U937 leukemia cell line

The present study was designed to investigate the anti-cancer effects of Sea hare eggs (SE) in U937 cells and its major active components. The aqueous extract of SE (ASE), which contained the highest protein content, dose-dependently inhibited the cancer cell's growth (IC₅₀ value, 10.42 ± 0.5 µg/mL). Additionally, ASE markedly caused DNA damage by inducing apoptotic body formation, DNA fragmentation, and accumulation of sub-G₁ DNA contents. ASE induced apoptosis by activating caspase-3 and 9 and poly (ADP-ribose) polymerase (PARP) by regulating the expression of Bcl-2/Bax. Moreover, among its molecular weight fractions, the > 30 kDa fraction showed the highest cell-growth-inhibitory effects, which was inhibited by heat treatment. Furthermore, the > 30 kDa fraction had markedly higher glycine content than the ASE. The presence of two protein bands at around 16 and 32 kDa was identified. In addition, two fractions, F1 and F2, were obtained using anion-exchange chromatography, with the F1 having an improved cell-growth-inhibitory effect than the > 30 kDa fraction. Taken together, these results suggest that the ASE contains glycine-rich proteins, including the active 16 and 32 kDa proteins, which account for its anti-cancer effects by inducing apoptosis via regulation of the mitochondrial pathway.

In vitro CRISPR-Cas9-mediated efficient Ad5 vector modification

The CRISPR-Cas9 genome editing system has been widely used in multiple cells and organisms. Here we developed a CRISPR-Cas9 based in vitro large DNA vector editing system, using the Ad5-based vector as an example. We demonstrate use of this system to generate targeted mutations, in-frame gene deletion, and gene replacement. This in vitro CRISPR editing system exhibits high efficiency and accuracy. We believe this system can be applied in a variety of experimental settings.

BH4 domain of Bcl-2 as a novel target for cancer therapy

Overexpression of B cell lymphoma 2 (Bcl-2) proteins is associated with therapy resistance in various human cancers. Traditional approaches target the Bcl-2 homology (BH)3 domain of Bcl-2; however, the BH4 domain represents a superior therapeutic target in light of its unique structure and crucial involvement in many cellular functions. In this critical review, we focus on the structural and functional basis of targeting the BH4 domain of Bcl-2, and highlight the recent advances in drug discovery efforts toward small-molecule BH4 domain inhibitors (e.g. BDA-366). The proof-of-concept studies support the hypothesis that targeting the BH4 domain of Bcl-2 holds promise to offer a novel anticancer therapy through the induction of apoptosis and an increased potential to overcome therapeutic resistance.

Direct Activation of Bax Protein for Cancer Therapy

Bax, a central cell death regulator, is an indispensable gateway to mitochondrial dysfunction and a major proapoptotic member of the B-cell lymphoma 2 (Bcl-2) family proteins that control apoptosis in normal and cancer cells. Dysfunction of apoptosis renders the cancer cell resistant to treatment as well as promotes tumorigenesis. Bax activation induces mitochondrial membrane permeabilization, thereby leading to the release of apoptotic factor cytochrome c and consequently cancer cell death. A number of drugs in clinical use are known to indirectly activate Bax. Intriguingly, recent efforts demonstrate that Bax can serve as a promising direct target for small-molecule drug discovery. Several direct Bax activators have been identified to hold promise for cancer therapy with the advantages of specificity and the potential of overcoming chemo- and radioresistance. Further investigation of this new class of drug candidates will be needed to advance them into the clinic as a novel means to treat cancer.

Why anti-Bcl-2 clinical trials fail: a solution

The alteration in expression of B cell lymphoma-2 (Bcl-2) family of protein members in cancer is involved mainly in the regulation of apoptosis. Bcl-2 family proteins are currently used as major targets in the development of methods to improve treatment outcomes for cancer patients that underwent clinical trials. Although many agents have been developed for targeting Bcl-2 in the past decade, some previous attempts to target Bcl-2 have not resulted in beneficial clinical outcome for reasons unknown. Here, we propose that this was due in part for not considering the cellular level of a different antiapoptotic protein, i.e., galectin-3 (Gal-3). Gal-3 is a member of the β-galactoside binding protein family and a multifunctional oncogenic protein which regulates cell growth, cell adhesion, cell proliferation, angiogenesis, and apoptosis. Gal-3 is the sole protein that contains the NWGR anti-death motif of the Bcl-2 family and inhibits cell apoptosis induced by chemotherapeutic agents through phosphorylation, translocation and regulation of survival signaling pathways. It is now established that Gal-3 is a candidate target protein to suppress antiapoptotic activity and anticancer drug resistance. In this review, we describe the role and relevance of Gal-3 and Bcl-2 protein family in the regulation of apoptosis and propose a novel combination therapy modality. Combination therapy that targets Gal-3 could be essential for improvement of the efficacy of Bcl-2 targeting therapy in cancers and should be studied in future clinical trials. Otherwise, not considering Gal-3 cellular level could lead to trial failure.

In vitro and in vivo evaluation of novel cinnamyl sulfonamide hydroxamate derivative against colon adenocarcinoma

The potential of cinnamic acid as an anti-inflammatory and anti-cancer agent has been studied previously. In our investigation, novel bio-isosters of cinnamyl sulfonamide hydroxamate were synthesized, characterized and confirmed for their structure and evaluated for cytotoxicity. Three NCEs namely, NMJ-1, -2 and -3 showed cell-growth inhibition in 6 human cancer cell lines with IC50 at the range of 3.3±0.15-44.9±2.6 μM. The hydroxamate derivatives of cinnamyl sulfonamide are reported inhibitors of HDAC enzyme. Thus, the effectiveness of these molecules was determined by whole cell HDAC assay in HCT 116 cell line. NMJ-2 (0.41±0.01 μM) exhibited better enzyme inhibition (IC50) compared to SAHA (2.63±0.07). In order to evaluate induction of apoptosis by treatment, Hoechst 33342 and AO/EB nuclear staining methods were used. Further, cell cycle analysis, Annexin V binding and caspase 3/7 activation assays were performed by flow cytometry where NMJ-2 significantly arrested the cell cycle at G2/M phase, increased Annexin V binding to the cell surface and activation of caspase-3/7. Bax/Bcl-2 ratio was observed by Western blot and showed an increase with NMJ-2 treatment. This was comparable to standard SAHA. The acute toxicity study (OECD-425) showed that NMJ-2 was safe up to 2000 mg/kg in rats. 1,2-Dimethyl hydrazine (DMH) was used to produce experimental colon adenocarcinoma in Wistar rats. 5-FU and NMJ-2 (100 mg/kg p.o. and 10 mg/kg i.p. once daily for 21 days, respectively) were administered to the respective groups. Both treatments significantly reduced ACFs, adenocarcinoma count, TNF-α, IL-6, nitrite and nitrate levels in colonic tissue. Our findings indicate that NMJ-2 has potent anti-cancer activity against colon cancer, by acting through HDAC enzyme inhibition and activation of intrinsic mitochondrial apoptotic pathway, with additional anti-inflammatory activity.

Oestrous cycle-dependent expression of Fas and Bcl2 family gene products in normal canine endometrium

During the oestrous cycle canine endometrium undergoes cyclical cellular proliferation, apoptosis and differentiation. To study the regulation of endometrial apoptosis and proliferation events the expression of apoptosis-related genes was analysed by real-time polymerase chain reaction and cellular expression of their proteins was identified through immunohistochemistry. Cellular apoptosis and proliferation events were detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) and proliferation marker Ki67 immunostaining, respectively. The highest proliferative index was observed in the follicular phase (all endometrial cellular components) and at early dioestrus (basal glands). This was associated with a low apoptotic index and a strong expression of anti- (Bcl2) and pro-apoptotic proteins (Fas, FasL, Bax). Subsequently (Days 11-45 of dioestrus), basal glandular epithelium experienced the highest apoptotic index, coincidental with a decrease of Bcl2 expression and a low ratio of Bcl2/Bax transcription. An increase in the apoptotic index of crypts, stromal and endothelial cells was observed at late dioestrus and the beginning of anoestrus. These results indicate that pro- and anti-apoptotic proteins regulate the balance between cell proliferation and death in the canine endometrium during the oestrous cycle. High Bcl2 expression in both the follicular and early dioestrous phases stimulate glandular proliferation and prevent apoptosis but, in the non-pregnant uterus, a decrease in Bcl2 expression together with an increase in pro-apoptotic proteins induces apoptosis of basal glandular epithelium cells.

Mitochondrial protection by the mixed muscarinic/σ1 ligand ANAVEX2-73, a tetrahydrofuran derivative, in Aβ25-35 peptide-injected mice, a nontransgenic Alzheimer's disease model

Alzheimer's disease (AD), the most prevalent dementia in the elderly, is characterized by progressive synaptic and neuronal loss. Mitochondrial dysfunctions have been consistently reported as an early event in AD and appear before Aβ deposition and memory decline. In order to define a new neuroprotectant strategy in AD targeting mitochondrial alterations, we develop tetrahydro-N,N-dimethyl-2,2-diphenyl-3-furanmethanamine (ANAVEX2-73, AE37), a mixed muscarinic receptor ligand and a sigma-1 receptor (σ1R) agonist. We previously reported that ANAVEX2-73 shows anti-amnesic and neuroprotective activities in mice injected intracerebroventricular (ICV) with oligomeric amyloid-β25-35 peptide (Aβ25-35). The σ1R is present at mitochondria-associated endoplasmic reticulum (ER) membranes, where it acts as a sensor/modulator of ER stress responses and local Ca(2+) exchanges with the mitochondria. We therefore evaluated the effect of ANAVEX2-73 and PRE-084, a reference σ1R agonist, on preservation of mitochondrial integrity in Aβ25-35-injected mice. In isolated mitochondria from hippocampus preparations of Aβ25-35 injected animals, we measured respiration rates, complex activities, lipid peroxidation, Bax/Bcl-2 ratios and cytochrome c release into the cytosol. Five days after Aβ25-35 injection, mitochondrial respiration in mouse hippocampus was altered. ANAVEX2-73 (0.01-1 mg/kg IP) restored normal respiration and PRE-084 (0.5-1 mg/kg IP) increased respiration rates. Both compounds prevented Aβ25-35-induced increases in lipid peroxidation levels, Bax/Bcl-2 ratio and cytochrome c release into the cytosol, all indicators of increased toxicity. ANAVEX2-73 and PRE-084 efficiently prevented the mitochondrial respiratory dysfunction and resulting oxidative stress and apoptosis. The σ1R, targeted selectively or non-selectively, therefore appears as a valuable target for protection against mitochondrial damages in AD.

A low toxic synthetic dendrimer conjugated podophyllotoxin nanodevice with potent antitumor activity against the DMBA/TPA induced mouse skin carcinogenesis model

D-PODO in tumor-bearing mice revealed a 50%–60% inhibition of skin tumor formation and reduced toxicity compared to PODO.

The role of visfatin on the regulation of inflammation and apoptosis in the spleen of LPS-treated rats

The purpose of the present study is to determine if visfatin is involved in inflammation or apoptosis induced by LPS in rat. Forty Wistar rats were divided into four groups: saline group, LPS group, visfatin group and Visfatin + LPS co-stimulated group. Spleen samples from each group of rats were collected for study. The spleen structure was examined by histological imaging. Apoptosis was evaluated with TUNEL reaction. Caspase-3 was detected with immunohistochemistry and western blot. The apoptosis-related genes were detected by qPCR and inflammatory cytokines were tested by ELISA. Our main findings were as follows. (1) Macrophages were markedly increased in the visfatin group compared with the saline group. This finding was confirmed when spleen samples were examined with western blot using CD68 antibody. (2) Visfatin promoted the expression of CD68 and caspase-3 in rat spleen, whereas visfatin could inhibit the expression of CD68 and activated caspase-3 in spleen of LPS-induced acute inflammation. (3) Visfatin had a pro-apoptotic effect on normal rat spleen, whereas it exerted an anti-apoptotic effect during LPS-induced lymphocytes apoptosis in rat spleen. Moreover, the effect of visfatin on cell apoptosis was mediated by the mitochondrial pathway. (4) Visfatin could modulate both the anti-inflammatory cytokines and pro-inflammatory cytokines in rat spleen, such as IL-10, IL-4, IL-6, TNF-α and IL-1β. Taken together, we demonstrate that visfatin could participate in the inflammatory process in rat spleen by modulating the macrophages and inflammatory cytokines. Also, visfatin plays a dual role in the apoptosis in rat spleen, which is mediated by the mitochondrial pathway.

Altered lipid levels provide evidence for myelin dysfunction in multiple system atrophy

Multiple system atrophy (MSA) is a rapidly-progressive neurodegenerative disease characterized by parkinsonism, cerebellar ataxia and autonomic failure. A pathological hallmark of MSA is the presence of α-synuclein deposits in oligodendrocytes, the myelin-producing support cells of the brain. Brain pathology and in vitro studies indicate that myelin instability may be an early event in the pathogenesis of MSA. Lipid is a major constituent (78% w/w) of myelin and has been implicated in myelin dysfunction in MSA. However, changes, if any, in lipid level/distribution in MSA brain are unknown. Here, we undertook a comprehensive analysis of MSA myelin. We quantitatively measured three groups of lipids, sphingomyelin, sulfatide and galactosylceramide, which are all important in myelin integrity and function, in affected (under the motor cortex) and unaffected (under the visual cortex) white matter regions. For all three groups of lipids, most of the species were severely decreased (40-69%) in affected but not unaffected MSA white matter. An analysis of the distribution of lipid species showed no significant shift in fatty acid chain length/content with MSA. The decrease in lipid levels was concomitant with increased α-synuclein expression. These data indicate that the absolute levels, and not distribution, of myelin lipids are altered in MSA, and provide evidence for myelin lipid dysfunction in MSA pathology. We propose that dysregulation of myelin lipids in the course of MSA pathogenesis may trigger myelin instability.

Phenoptosis in yeasts

The current view on phenoptosis and apoptosis as genetic programs aimed at eliminating potentially dangerous organisms and cells, respectively, is given. Special emphasis is placed on apoptosis (phenoptosis) in yeasts: intracellular defects and a plethora of external stimuli inducing apoptosis in yeasts; distinctive morphological and biochemical hallmarks accompanying apoptosis in yeasts; pro- and antiapoptotic factors involved in yeast apoptosis signaling; consecutive stages of apoptosis from external stimulus to the cell death; a prominent role of mitochondria and other organelles in yeast apoptosis; possible pathways for release of apoptotic factors from the intermembrane mitochondrial space into the cytosol are described. Using some concrete examples, the obvious physiological importance and expediency of altruistic death of yeast cells is shown. Poorly known aspects of yeast apoptosis and prospects for yeast apoptosis study are defined.

A design for the control of apoptosis in genetically modified Saccharomyces cerevisiae

We have engineered a system that holds potential for use as a safety switch in genetically modified yeasts. Human apoptotic factor BAX (no homolog in yeast), under the control of the FBP1 (gluconeogenesis enzyme) promoter, was conditionally expressed to induce yeast cell apoptosis after glucose depletion. Such systems might prove useful for the safe use of genetically modified organisms.

The structural biology of BH3-only proteins

B-cell lymphoma-2 (Bcl-2) homology-3 (BH3)-only proteins are considered members of the Bcl-2 family, though they bear little sequence or structural identity with the multi-BH motif prosurvival or proapoptotic Bcl-2 proteins like Bcl-2 or Bax. They are better considered a separate phylogenetic entity. In combination, results from biophysical, biochemical, cell biological, and animal studies in conjunction with structural investigations have elucidated the function and mechanism of action of these proteins. Either by antagonizing prosurvival Bcl-2 proteins or directly activating proapoptotic Bcl-2 proteins (Bax or Bak) they initiate apoptosis. BH3-only proteins are intrinsically disordered and fold and bind into a groove provided by their cognate receptor Bcl-2 family proteins. Our detailed molecular understanding of BH3-only protein action has aided the development of novel chemical entities that initiate cell death by mimicking the properties of BH3-only proteins.

Exposure to the neurotoxic dinoflagellate, Alexandrium catenella, induces apoptosis of the hemocytes of the oyster, Crassostrea gigas

This study assessed the apoptotic process occurring in the hemocytes of the Pacific oyster, Crassostrea gigas, exposed to Alexandrium catenella, a paralytic shellfish toxins (PSTs) producer. Oysters were experimentally exposed during 48 h to the toxic algae. PSTs accumulation, the expression of 12 key apoptotic-related genes, as well as the variation of the number of hemocytes in apoptosis was measured at time intervals during the experiment. Results show a significant increase of the number of hemocytes in apoptosis after 29 h of exposure. Two pro-apoptotic genes (Bax and Bax-like) implicated in the mitochondrial pathway were significantly upregulated at 21 h followed by the overexpression of two caspase executor genes (caspase-3 and caspase-7) at 29 h, suggesting that the intrinsic pathway was activated. No modulation of the expression of genes implicated in the cell signaling Fas-Associated protein with Death Domain (FADD) and initiation-phase (caspase-2) was observed, suggesting that only the extrinsic pathway was not activated. Moreover, the clear time-dependent upregulation of five (Bcl2, BI-1, IAP1, IAP7B and Hsp70) inhibitors of apoptosis-related genes associated with the return to the initial number of hemocytes in apoptosis at 48 h of exposure suggests the involvement of strong regulatory mechanisms of apoptosis occurring in the hemocytes of the Pacific oyster.

Galectin-3 inhibition sensitizes human renal cell carcinoma cells to arsenic trioxide treatment

The anti-tumor effects of arsenic trioxide (ATO) were well established in acute promyelocytic leukemia, but not in renal cell carcinoma (RCC). Recent evidences indicate that galectin-3 (Gal-3) plays an anti-apoptotic role in chemotherapy induced tumor cell death. This study was intended to clarify the exact roles of Gal-3 performed in ATO-induced apoptosis in RCC cells. Weak apoptosis was observed in Gal-3-positive RCC cells (Caki-1, Caki-2, 786-0, and ACHN) following ATO treatment. However, ATO treatment upregulated Gal-3 expression concurrently caused a Synexin-cooperated translocation of Gal-3 from the nucleus to the cytoplasm. Gal-3-knockdown cells were more sensitive to ATO treatment as indicated by a strong mitochondria-dependent apoptosis following ATO treatment. Meanwhile, Gal-3 was found to inhibit ATO-induced apoptosis through enhancing Bcl-2 expression and stabilizing mitochondria. To confirm the results obtained from genetic method, we employed a Gal-3 inhibitor, modified citrus prectin (MCP), and co-treated the RCC cells with ATO. The cells showed an increased apoptosis in the syngeneic application of Gal-3 inhibition and ATO compared with ATO application alone. Based on these results, we conclude that Gal-3 inhibition sensitizes human renal cell carcinoma cells to ATO treatment through increasing mitochondria-dependent apoptosis. Our studies implicate synergetic application of ATO and Gal-3 inhibition as a potential strategy for RCC treatment.

Safflor yellow A protects neonatal rat cardiomyocytes against anoxia/reoxygenation injury in vitro

AIM

To investigate the effects of safflor yellow A (SYA), a flavonoid extracted from Carthamus tinctorius L, on cultured rat cardiomyocytes exposed to anoxia/reoxygenation (A/R).

METHODS

Primary cultured neonatal rat cardiomyocytes were exposed to anoxia for 3 h followed by reoxygenation for 6 h. The cell viability was measured using MTT assay. The releases of lactate dehydrogenase (LDH) and creatine kinase (CK), level of malondialdehyde (MDA), and activities of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were analyzed. Hoechst 33258 staining and changes in Bcl-2/Bax ratio and caspase 3 activity were used to examine A/R-induced apoptosis.

RESULTS

The A/R exposure markedly decreased the viability of cardiomyocytes, suppressed the activities of SOD, GSH, CAT and GSH-Px, and Bcl-2 protein expression. Meanwhile, the A/R exposure markedly increased the release of LDH and CK, and MDA production in the cardiomyocytes, and increased the rate of apoptosis, caspase 3 activity, Bax protein expression. Pretreatment with SYA (40, 60 and 80 nmol/L) concentration-dependently blocked the A/R-induced changes in the cardiomyocytes. Pretreatment of the cardiomyocytes with the antioxidant N-acetylcysteine (NAC, 200 μmol/L) produced protective effects that were comparable to those caused by SYA (80 nmol/L).

CONCLUSION

SYA protects cultured rat cardiomyocytes against A/R injury, maybe via inhibiting cellular oxidative stress and apoptosis.

Identification of a motif in BMRP required for interaction with Bcl-2 by site-directed mutagenesis studies

Bcl-2 is an anti-apoptotic protein that inhibits apoptosis elicited by multiple stimuli in a large variety of cell types. BMRP (also known as MRPL41) was identified as a Bcl-2 binding protein and shown to promote apoptosis. Previous studies indicated that the amino-terminal two-thirds of BMRP contain the domain(s) required for its interaction with Bcl-2, and that this region of the protein is responsible for the majority of the apoptosis-inducing activity of BMRP. We have performed site-directed mutagenesis analyses to further characterize the BMRP/Bcl-2 interaction and the pro-apoptotic activity of BMRP. The results obtained indicate that the 13-17 amino acid region of BMRP is necessary for its binding to Bcl-2. Further mutagenesis of this motif shows that amino acid residue aspartic acid (D) 16 of BMRP is essential for the BMRP/Bcl-2 interaction. Functional analyses conducted in mammalian cells with BMRP site-directed mutants BMRP(13Ala17) and BMRP(D16A) indicate that these mutants induce apoptosis through a caspase-mediated pathway, and that they kill cells slightly more potently than wild-type BMRP. Bcl-2 is still able to counteract BMRP(D16A)-induced cell death significantly, but not as completely as when tested against wild-type BMRP. These results suggest that the apoptosis-inducing ability of wild-type BMRP is blocked by Bcl-2 through several mechanisms.

CDK-associated Cullin 1 can promote cell proliferation and inhibit cisplatin-induced apoptosis in the AGS gastric cancer cell line

Background

Gastric cancer is a common and highly lethal malignancy in the world, but its pathogenesis remains elusive. In this study, we focus on the biological functions of CDK-associated Cullin1 (CAC1), a novel gene of the cullin family, in gastric cancer, which may help us to further understand the origin of this malignancy.

Methods

The AGS and MGC803 gastric cancer cell lines and the GES-1 gastric mucosa cell line were selected for study. At first, CAC1 expressions of those cell lines were examined by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and western blot examinations, then CAC1 small interfering RNA (CAC1-siRNA) were designed and transfected into the AGS cell line with a relatively high level of CAC1. Once CAC1 was silenced, a series of biological characteristics of AGS cells such as cell proliferation, cell cycle, apoptosis, and expressions of apoptosis-related genes (P53, BCL2 and BAX) were determined by MTT, flow cytometry, qRT-PCR and western blot, respectively.

Results

CAC1 expression of AGS or MGC803 was much higher than that of GES-1. After CAC1 expression was effectively depressed by RNA interference in AGS cells, significant cell growth inhibition occurred. Furthermore, the proportion of cells treated with CAC1-siRNA increased in the G1 phase and decreased in the S phase, indicative of G1 cell cycle arrest. More importantly, the proportions of early/late apoptosis in AGS cells were enhanced with cis-diaminedichloroplatinum (cisplatin, CDDP) treatment, but to a higher extent with cisplatin plus CAC1-siRNA. Interestingly, BCL2 mRNA copies showed about a 30% decrease in the cisplatin group, but dropped by around 60% in the cisplatin plus CAC1-siRNA group. Conversely, the P53 mRNA expressions obtained nearly a two-fold increase in the cisplatin group, in addition to a five-fold increase in the cisplatin plus CAC1-siRNA group, and the BAX mRNA levels had almost a two- and four-fold augmentation, respectively. Meanwhile, P53, BAX and BCL2 showed the same alteration patterns in western blot examinations.

Conclusions

CAC1 can promote cell proliferation in the AGS gastric cancer cell line. Moreover, it can prevent AGS cells from experiencing cisplatin-induced apoptosis via modulating expressions of P53, BCL2 and BAX.

PSAP induces a unique Apaf-1 and Smac-dependent mitochondrial apoptotic pathway independent of Bcl-2 family proteins

Presenilin-associated protein (PSAP) has been identified as a mitochondrial proapoptotic protein. However, the mechanism by which PSAP induces apoptosis remains unknown. To this end, we have established an inducible expression system. Using this system, we have examined the roles of B-cell lymphoma 2 (Bcl-2) family proteins, cytochrome c, Smac (Smac/Diablo, second mitochondria-derived activator of caspases/direct IAP binding protein with low PI), and Apaf-1 (apoptotic protease-activating factor) in PSAP-induced apoptosis. Our results demonstrate that knockdown of Apaf-1 abolished PSAP-induced caspase activation and poly(ADP ribose) polymerase (PARP) cleavage, indicating that the apoptosome formation triggered by cytochrome c is crucial for PSAP-induced apoptosis. Our data also demonstrate that knockdown of Smac abolished PSAP-induced caspase activation and PARP cleavage, indicating that, in addition to Apaf-1 or apoptosome formation, Smac is also essential for PSAP-induced apoptosis. However, interestingly, our data demonstrate that overexpression of Bcl-2 and Bcl-xL did not protect cells from PSAP-induced apoptosis, and that knockdown of Bid, Bax, and Bak had no effect on PSAP-induced cytochrome c and Smac release, indicating that PSAP-induced apoptosis is not regulated by Bcl-2 family proteins. These results strongly suggest that PSAP evokes mitochondrial apoptotic cascades via a novel mechanism that is not regulated by Bcl-2 family proteins, but that both the formation of cytochrome c-Apaf-1 apoptosome and the presence of Smac are absolutely required for PSAP-induced apoptosis.

Saccharomyces cerevisiae as a model system to study the response to anticancer agents

The development of new strategies for cancer therapeutics is indispensable for the improvement of standard protocols and the creation of other possibilities in cancer treatment. Yeast models have been employed to study numerous molecular aspects directly related to cancer development, as well as to determine the genetic contexts associated with anticancer drug sensitivity or resistance. The budding yeast Saccharomyces cerevisiae presents conserved cellular processes with high homology to humans, and it is a rapid, inexpensive and efficient compound screening tool. However, yeast models are still underused in cancer research and for screening of antineoplastic agents. Here, the employment of S. cerevisiae as a model system to anticancer research is discussed and exemplified. Focusing on the important determinants in genomic maintenance and cancer development, including DNA repair, cell cycle control and epigenetics, this review proposes the use of mutant yeast panels to mimic cancer phenotypes, screen and study tumor features and synthetic lethal interactions. Finally, the benefits and limitations of the yeast model are highlighted, as well as the strategies to overcome S. cerevisiae model limitations.

Effect of ursolic acid treatment on apoptosis and DNA damage in isoproterenol-induced myocardial infarction

The present study was designed to evaluate the protective effect of ursolic acid (UA) against isoproterenol-induced myocardial infarction. Myocardial infarction was induced by subcutaneous injection of isoproterenol hydrochloride (ISO) (85 mg/kg BW), for two consecutive days. ISO-induced rats showed elevated levels of cardiac troponins T (cTn T) and I (cTn I) and increased activity of creatine kinase-MB (CK-MB) in serum. Lipid peroxidative markers (thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and lipid hydroperoxides (HP)) elevated in the plasma and heart tissue whereas decreased activities of enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR)) in erythrocytes and heart tissue of ISO-induced rats. Non-enzymatic antioxidants (vitamin C, vitamin E and reduced glutathione (GSH)) levels were decreased significantly in the plasma and heart tissue of ISO-induced rats. Furthermore, ISO-induced rats showed increased DNA fragmentation, upregulations of myocardial pro-apoptotic B-cell lymphoma-2 associated-x (Bax), caspase-3, -8 and -9, cytochrome c, tumor necrosis factor-α (TNF-α), Fas and down-regulated expressions of anti-apoptotic B-cell lymphoma-2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xL). UA-administered rats showed decreased levels/activity of cardiac markers, DNA fragmentation and the levels of lipid peroxidative markers in the plasma and heart tissue. Activities of enzymatic antioxidants were increased significantly in the erythrocytes and heart tissue and also non-enzymatic antioxidants levels were increased significantly in the plasma and heart tissue in UA-administered rats. UA influenced decreased DNA fragmentation and an apoptosis by upregulation of anti-apoptotic proteins such as Bcl-2, Bcl-xL and down-regulation of Bax, caspase-3, -8 and -9, cytochrome c, TNF-α, Fas through mitochondrial pathway. Histopathological observations were also found in line with biochemical parameters. Thus, results of the present study demonstrated that the UA has anti-apoptotic properties in ISO-induced rats.

Systems biology of yeast cell death

Programmed cell death (PCD) (including apoptosis) is an essential process, and many human diseases of high prevalence such as neurodegenerative diseases and cancer are associated with deregulations in the cell death pathways. Yeast Saccharomyces cerevisiae, a unicellular eukaryotic organism, shares with multicellular organisms (including humans) key components and regulators of the PCD machinery. In this article, we review the current state of knowledge about cell death networks, including the modeling approaches and experimental strategies commonly used to study yeast cell death. We argue that the systems biology approach will bring valuable contributions to our understanding of regulations and mechanisms of the complex cell death pathways.

New insights into cancer-related proteins provided by the yeast model

Cancer is a devastating disease with a profound impact on society. In recent years, yeast has provided a valuable contribution with respect to uncovering the molecular mechanisms underlying this disease, allowing the identification of new targets and novel therapeutic opportunities. Indeed, several attributes make yeast an ideal model system for the study of human diseases. It combines a high level of conservation between its cellular processes and those of mammalian cells, with advantages such as a short generation time, ease of genetic manipulation and a wealth of experimental tools for genome- and proteome-wide analyses. Additionally, the heterologous expression of disease-causing proteins in yeast has been successfully used to gain an understanding of the functions of these proteins and also to provide clues about the mechanisms of disease progression. Yeast research performed in recent years has demonstrated the tremendous potential of this model system, especially with the validation of findings obtained with yeast in more physiologically relevant models. The present review covers the major aspects of the most recent developments in the yeast research area with respect to cancer. It summarizes our current knowledge on yeast as a cellular model for investigating the molecular mechanisms of action of the major cancer-related proteins that, even without yeast orthologues, still recapitulate in yeast some of the key aspects of this cellular pathology. Moreover, the most recent contributions of yeast genetics and high-throughput screening technologies that aim to identify some of the potential causes underpinning this disorder, as well as discover new therapeutic agents, are discussed.

Investigation of the Bcl-2 multimerisation process: structural and functional implications

Bcl-2 plays a prominent role in regulating the function of mitochondria during respiration and in determining the threshold of apoptotic sensitivity. Despite its relevance, the mechanism through which these processes are achieved is still unknown. Using surface plasmon resonance technology to monitor Bcl-2 multimerisation we discovered that a simple dimeric model does not fit with experimental data. A molecular model of the experimentally observed Bcl-2 homomeric complex has been developed. Accordingly, using a panel of mutants we identified in the loop a critical region for the process of Bcl-2 multimerisation. Our results indicate that the Bcl-2 loop posttranscriptional changes can modulate its ability to make homo and hetero-complexes, ultimately leading to functional modulation, suggesting an intriguing relationship between the ability of Bcl-2 to form multimeric complexes and its multi-functional role as a membrane channel. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.