Proteases for cell suicide: functions and regulation of caspases

Calvatia Lilacina Extracts Exert Anti-Breast-Cancer Bioactivity through the Apoptosis Induction Dependent on Mitochondrial Reactive Oxygen Species and Caspase Activation

Puffballs are a class of fungi widely distributed worldwide and associated with various bioactivities. This research mainly showed the antitumor bioactivity of extracts from Calvatia lilacina (CL), which is a common variety of puffballs. NMR and high-performance liquid chromatography methods are used to characterize the extracts. Results showed that CL extracts obtained with petroleum ether, ethyl acetate, ethanol, and water elicited obvious inhibitory effects on the proliferation of A549, Caco-2, and MDA-MB-231. Among these extracts, petroleum ether extract demonstrated the highest performance. This extract was then separated into seven sub-fractions (SFs). Three of these SFs (3#, 6#, and 7#) induces a decrease in the viability of MDA-MB-231 cells in which 7# SF exhibited the highest cytotoxicity, where the major component was found to be ergosta-7,22-dien-3-one. Further tests revealed that 7# SF from petroleum ether extract could trigger severe cell death in human breast cancer cells (MDA-MB-231) by activating the apoptotic pathway dependent on mitochondrial reactive oxygen species and caspase activation. All these results in combination indicate that the mechanism of extract-potentiated apoptosis associates closely with ROS-dependent mitochondrial dysfunction events which further induces mitochondria-mediated intrinsic cytochrome C-caspase-related pathway of apoptosis.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1936576.

Effects of Notch2 on proliferation, apoptosis and steroidogenesis in bovine luteinized granulosa cells

Notch signaling pathway plays an important regulatory role in the development of mammalian follicles. This study aimed to explore the effect of Notch2 on the function of bovine follicles luteinized granulosa cells (LGCs). We detected that the coding sequence (CDS) of bovine Notch2 gene is 7416 bp, encoding 2471 amino acids (AA). The homology of Notch2 AA sequence between bovine and other species is 86.04%-98.75%, indicating high conservatism. Immunohistochemistry found that Notch2 receptor and its ligand Jagged2 localize in granulosa cells (GCs) and theca cells in bovine antral follicles. And immunofluorescence found that positive signals of Notch2 and Jagged2 overlap in bovine LGCs, speculating that Notch2 receptor may react with Jagged2 ligand to activate Notch signaling pathway and play an important role in bovine LGCs. To further investigate the function of Notch2, Notch2 gene was silenced by short hairpin RNA (shRNA) and CCK-8 analysis showed that the proliferation rate of LGCs was downregulated significantly (P < 0.01). Quantitative reverse transcription polymerase chain reaction (qRT-PCR) showed that the mRNA expression of apoptosis related gene Bcl-2/Bax decreased (P < 0.01) and Caspase3 increased (P < 0.05), cell cycle related gene CyclinD2/CDK4 complex decreased (P < 0.01) and P21 increased (P < 0.05), steroidogenesis gene STAR and 3β-HSD decreased (P < 0.01) while CYP19A1 and CYP11A1 had no significant difference (P > 0.05). In addition, Enzyme-linked immunosorbent assay (ELISA) showed that there was no difference in estradiol (E₂) secretion (P > 0.05) while the progesterone (P₄) secretion decreased (P < 0.01). In conclusion, Notch2 plays an important role in regulating bovine LGCs development.

The effect of caspase-9 in the differentiation of SH-SY5Y cells

Neuroblastoma is the most common solid malignant tumor in infants and young children. Its origin is the incompletely committed precursor cells from the autonomic nervous system. Neuroblastoma cells are multipotent cells with a high potency of differentiation into the neural cell types. Neural differentiation leads to the treatment of neuroblastoma by halting the cell and tumor growth and consequently its expansion. Caspases are a family of proteins involved in apoptosis and differentiation. The present study aimed to investigate the potential role of caspase-9 activation on the differentiation of the human neuroblastoma SH-SY5Y cells. Here we investigated the caspase-9 and 3/7 activity during 1,25-dihydroxycholecalciferol (D3)-mediated differentiation of SH-SY5Y cells and took advantage of the inducible caspase-9 system in putting out the differentiation of the neuroblastoma cells. D3-induced differentiation of the cells could lead to activation of caspase-9 and caspase-3/7, astrocyte-like morphology, and increased expression of Glial fibrillary acidic protein (GFAP). By using the inducible caspase-9 system, we showed differentiation of SH-SY5Y cells to astrocyte-like morphology and increased level of GFAP expression. Furthered studies using a specific caspase-9 inhibitor showed inhibition of differentiation mediated by D3 or caspase-9 to astrocyte-like cells. These results show the potency of caspase-9 to direct differentiation of the human neuroblastoma SH-SY5Y cells into cells showing an astrocyte-like morphology.

Deubiquitinases: Modulators of Different Types of Regulated Cell Death

The mechanisms and physiological implications of regulated cell death (RCD) have been extensively studied. Among the regulatory mechanisms of RCD, ubiquitination and deubiquitination enable post-translational regulation of signaling by modulating substrate degradation and signal transduction. Deubiquitinases (DUBs) are involved in diverse molecular pathways of RCD. Some DUBs modulate multiple modalities of RCD by regulating various substrates and are powerful regulators of cell fate. However, the therapeutic targeting of DUB is limited, as the physiological consequences of modulating DUBs cannot be predicted. In this review, the mechanisms of DUBs that regulate multiple types of RCD are summarized. This comprehensive summary aims to improve our understanding of the complex DUB/RCD regulatory axis comprising various molecular mechanisms for diverse physiological processes. Additionally, this review will enable the understanding of the advantages of therapeutic targeting of DUBs and developing strategies to overcome the side effects associated with the therapeutic applications of DUB modulators.

Efficient Stable Cell Line Generation of Survivin as an In Vitro Model for Specific Functional Analysis in Apoptosis and Drug Screening

Recognizing proteins that lead to a decreased efficiency of treatment in cancer cells constitutes a main goal for biomedical and biotechnological research and applications. Establishing recombinant cells that overexpress a gene of interest stably is important for treatment studies and drug/compound screening. Survivin is an anti-apoptotic protein which can be a potential candidate for regulating cell death and survival. To investigate the association between survivin increment and apoptosis rate, survivin-reconstituted HEK (HEK-S) cell was developed as in vitro model. RT-PCR and Western blot demonstrated that survivin was constitutively overexpressed in HEK-S cells. Both morphological observation and survival assay showed that HEK-S cells were significantly resistant to apoptotic stimuli. Survivin overexpression led to a decrease in caspase 3/7 activity, whereas YM155 led to a corresponding enhance of caspase activity. ROS level was decreased but ATP content increased in HEK-S cells. Also, HEK-S showed less red- fluorescence and reduced cell proliferation compared to HEK after stimulation. Resistance to laser irradiation was clearly visible as compared with control. Moreover, scratching analysis demonstrated the ability of survivin to cause neighboring cells to increase resistance to drug, whereas YM155 enhanced apoptotic rate and declined invasion in HEK-S cells.

A Workflow towards the Reproducible Identification and Quantitation of Protein Carbonylation Sites in Human Plasma

Protein carbonylation, a marker of excessive oxidative stress, has been studied in the context of multiple human diseases related to oxidative stress. The variety of post-translational carbonyl modifications (carbonyl PTMs) and their low concentrations in plasma challenge their reproducible identification and quantitation. However, carbonyl-specific biotinylated derivatization tags (e.g., aldehyde reactive probe, ARP) allow for targeting carbonyl PTMs by enriching proteins and peptides carrying these modifications. In this study, an oxidized human serum albumin protein model (OxHSA) and plasma from a healthy donor were derivatized with ARP, digested with trypsin, and enriched using biotin-avidin affinity chromatography prior to nano reversed-phase chromatography coupled online to electrospray ionization tandem mass spectrometry with travelling wave ion mobility spectrometry (nRPC-ESI-MS/MS-TWIMS). The presented workflow addresses several analytical challenges by using ARP-specific fragment ions to reliably identify ARP peptides. Furthermore, the reproducible recovery and relative quantitation of ARP peptides were validated. Human serum albumin (HSA) in plasma was heavily modified by a variety of direct amino acid oxidation products and adducts from reactive carbonyl species (RCS), with most RCS modifications being detected in six hotspots, i.e., Lys10, Lys190, Lys199, Lys281, Lys432, and Lys525 of mature HSA.

A Highly Cellular Uptake Ternary Nanocomposite Titanate Nano-Tubes/CuFe₂O₄/Zn-Fe Could Induce Intrinsic Apoptosis of Prostate Cancer Cells: An Extended Study

Our previously prepared ternary nanocomposite TNT/CuFe₂O₄/Zn-Fe was highly engulfed by PC-3 cells, activated cytotoxicity that was dosage and time-subordinated, and demonstrated morphological alteration, which is one of the common characteristics of apoptotic cells. This prolonged study aimed to investigate other items. The study performed assays as Annexin V-FITC, flow cytometry, DNA ladder electrophoresis, and ROS assay for apoptosis detection, cell cycle analysis, DNA fragmentation, and ROS generation, respectively. In the PC-3-treated cells, the early and late phases of apoptosis with different percentages and DNA fragmentation were determined. Besides, the PC-3 cell cycle revealed the three major cell distribution different phases of the cycle (G1, S, and G2/M), and the Sub G1, which corresponded to apoptotic cells. The results proved the presence of ROS that triggered the intrinsic apoptotic pathway, which was confirmed through a decrease in (Bcl-2), the release of cytochrome c, activation of caspase-9, and caspase-3. To conclude, the ternary nanocomposite TNT/CuFe₂O₄/Zn-Fe achieved biochemical features alterations and could induce intrinsic apoptosis of PC-3 cells. The planned work of the current research will illuminate the arrested phase in the cell cycle through studying tumor suppressor genes such as p53 and Retinoblastoma RB, c-Myc oncogene, and cyclin-dependent kinases (Cdks) as well as their regulators.

Cell death mechanisms and their roles in pregnancy related disorders

Autophagy and apoptosis are catabolic pathways essential for homeostasis. They play a crucial role for normal placental and fetal development. These cell death mechanisms are exaggerated in placental disorders such as preeclampsia, intrauterine growth restriction (IUGR) and gestational diabetes mellitus (GDM). Apoptosis is widely studied, highly controlled and regulated whereas; autophagy is an orderly degradation and recycling of the cellular components. Cellular senescence may be initiated by a variety of stimuli, including hypoxia, oxidative stress, reduction in survival signals and nutrition deprivation. Apoptosis is regulated by two types of pathways intrinsic and extrinsic. Extrinsic pathway is initiated by apoptosis inducing cells such as macrophages, natural killer cells whereas; intrinsic pathway is initiated in response to DNA damage, cell injury and lack of oxygen. In autophagy, the cell or organelles undergo lysosomal degradation. Placental apoptosis increases as the gestation progresses while autophagy plays a role in trophoblast differentiation and invasion. In pregnancy disorders like preeclampsia and IUGR, proapoptotic markers such as caspase 3, 8, BAX are higher and antiapoptotic markers like Bcl-2 are lower. In GDM, apoptotic markers are reduced resulting in increased placental mass and fetal macrosomia. Apoptosis in the pathological pregnancies is also influenced by the reduced levels of micronutrients and long chain polyunsaturated fatty acids resulting in disturbed placental biology. This chapter describes the role of various key molecular events involved in cellular senescence and the various factors influencing them. This will help identify future therapeutic strategies for better management of these processes.

Cellular alterations and damage to the renal tissue of marine catfish Arius arius following Cd exposure and the possible sequestrant role of Metallothionein

Cd is a non-degradable heavy metal pollutant with no known biological role. When taken up by living organisms from the environment, it causes extensive tissue damage. Here, we studied the effects of exposure to 20 mg/L^-1CdCl₂for 0, 24, 48, and 72 h on the renal tissue of marine catfish Arius arius. Cd uptake, metallothionein (MT) induction, microarchitectural alterations, DNA fragmentation, and caspase-3 activity were studied. Cd and MT levels were time-dependent and positively correlated. The diameter of the Bowman's capsule and tubules was significantly increased. Meanwhile, the density, diameter, and volume of the glomerulus as well as the density and volume of tubules decreased. Cd induced apoptosis though elevatedcaspase-3 activity. These results support the notion that exposure to sublethal Cd levels induces oxidative stress, leading to structural and functional impairment of the kidneys. Cd uptake and MT induction can serve as useful environmental biomarkers.

Water-mediated structural rearrangement establishes active conformation of caspases for apoptosis and inflammation

Caspases are cysteine-dependent aspartate-specific proteases that play a crucial role in apoptosis (or programmed cell death) and inflammation. Based on their function, caspases are majorly categorized into apoptotic (initiator/apical and effector/executioner) and inflammatory caspases. Caspases undergo transition from an inactive zymogen to an active caspase to accomplish their function. This transition demands structural rearrangements which are most prominent at the active site loops and are imperative for the catalytic activity of caspases. In effector caspase-3, the structural rearrangement in the active site loop is shown to be facilitated by a set of invariant water (IW) molecules. However, the atomic details involving their role in stabilizing the active conformation have not been reported yet. Moreover, it is not known whether water molecules are essential for the active conformation in all caspases. Thus, in this study, we located IW molecules in initiator, effector, and inflammatory caspases to understand their precise role in rendering the structural arrangement of active caspases. Furthermore, IW molecules involved in anchoring the fragments of the protomer and rendering regulated flaccidity to caspases were identified. Location and identification of IW molecules interacting with amino acid residues involved in establishing the active conformation in the caspases might facilitate the design of potent inhibitors during up-regulated caspase activity in neurodegenerative and immune disorders. Communicated by Ramaswamy H. Sarma.

Phylogenetic analysis of the caspase family in bivalves: implications for programmed cell death, immune response and development

BACKGROUND

Apoptosis is an important process for an organism's innate immune system to respond to pathogens, while also allowing for cell differentiation and other essential life functions. Caspases are one of the key protease enzymes involved in the apoptotic process, however there is currently a very limited understanding of bivalve caspase diversity and function.

RESULTS

In this work, we investigated the presence of caspase homologues using a combination of bioinformatics and phylogenetic analyses. We blasted the Crassostrea gigas genome for caspase homologues and identified 35 potential homologues in the addition to the already cloned 23 bivalve caspases. As such, we present information about the phylogenetic relationship of all identified bivalve caspases in relation to their homology to well-established vertebrate and invertebrate caspases. Our results reveal unexpected novelty and complexity in the bivalve caspase family. Notably, we were unable to identify direct homologues to the initiator caspase-9, a key-caspase in the vertebrate apoptotic pathway, inflammatory caspases (caspase-1, - 4 or - 5) or executioner caspases-3, - 6, - 7. We also explored the fact that bivalves appear to possess several unique homologues to the initiator caspase groups - 2 and - 8. Large expansions of caspase-3 like homologues (caspase-3A-C), caspase-3/7 group and caspase-3/7-like homologues were also identified, suggesting unusual roles of caspases with direct implications for our understanding of immune response in relation to common bivalve diseases. Furthermore, we assessed the gene expression of two initiator (Cg2A, Cg8B) and four executioner caspases (Cg3A, Cg3B, Cg3C, Cg3/7) in C. gigas late-larval development and during metamorphosis, indicating that caspase expression varies across the different developmental stages.

CONCLUSION

Our analysis provides the first overview of caspases across different bivalve species with essential new insights into caspase diversity, knowledge that can be used for further investigations into immune response to pathogens or regulation of developmental processes.

The Role of Mitochondria in Brain Cell Protection from Ischaemia by Differently Prepared Propolis Extracts

Mitochondria are both the primary targets and mediators of ischaemic damage in brain cells. Insufficient oxygen causes reactive oxygen species that damage the mitochondria, leading to the loss of functionality and viability of highly energy-demanding neurons. We have recently found that aqueous (AqEP), polyethylene glycol-aqueous (Pg-AqEP) and ethanolic propolis extracts (EEP) can modulate mitochondria and ROS production in C6 cells of astrocytic origin. The aim of this study was to investigate the effect of the extracts on viability, mitochondrial efficiency and superoxide generation, and inflammatory cytokine release in primary rat cerebellar neuronal-glial cell cultures affected by ischaemia (mimicked by hypoxia +/- deoxyglucose). AqEP and Pg-AqEP (15-60 µg/mL of phenolic compounds, or PC) significantly increased neuronal viability in ischaemia-treated cultures, and this was accompanied by a reduction in mitochondrial superoxide levels. Less extended protection against ischaemia-induced superoxide production and death was exhibited by 2 to 4 µg/mL of PC EEP. Both Pg-AqEP and Ag-EP (but not EEP) significantly protected the cultures from hypoxia-induced elevation of TNF-α, IL-1β and IL-6. Only Pg-AqEP (but not AqEP or EEP) prevented hypoxia-induced loss of the mitochondrial basal and ATP-coupled respiration rate, and significantly increased the mitochondrial respiratory capacity. Summarising, the study revealed that hydrophilic propolis extracts might protect brain cells against ischaemic injury by decreasing the level of mitochondrial superoxide and preventing inflammatory cytokines, and, in the case of Pg-AqEP, by protecting mitochondrial function.

Constructing and evaluating caspase-activatable adeno-associated virus vector for gene delivery to the injured heart

Adeno-associated virus (AAV) is a promising vector for gene therapy, but its broad tropism can be detrimental if the transgene being delivered is harmful when expressed ubiquitously in the body, i.e. in non-target tissues. Delivering the transgene of interest to target cells at levels high enough to be therapeutically effective while maintaining safety by minimizing delivery to off-target cells is a prevalent challenge in the field of gene therapy. We have developed a protease activatable vector (provector) platform based on AAV9 that can be injected systemically to deliver therapeutic transgenes site-specifically to diseased cells by responding to extracellular proteases present at the disease site. The provector platform consists of a peptide insertion into the virus capsid which disrupts the virus' ability to bind to cell surface receptors. This peptide contains a blocking motif (aspartic acid residues) flanked on either side by cleavage sequences that are recognized by certain proteases. Exposure to proteases cleaves the peptides off the capsid, activating or "switching ON" the provector. In response to the activation, the provectors regain their ability to bind and transduce cells. Here, we have designed a provector that is activated by cysteine aspartic proteases (caspases), which have roles in inflammation and apoptosis and thus are elevated at sites of diseases such as heart failure, neurodegenerative diseases, and ischemic stroke. This provector demonstrates a 200-fold reduction in transduction ability in the OFF state compared to AAV9, reducing the virus' ability to transduce off-target healthy tissue. Following exposure to and proteolysis by caspase-3, the provector shows a 95-fold increase in transduction compared to the OFF state. The switchable transduction behavior was found to be a direct result of the peptide insertion ablating the ability of the virus to bind to cells. In vivo studies were conducted to characterize the biodistribution, blood circulation time, neutralizing antibody formation, and targeted delivery ability of the caspase-activatable provector in a model of heart failure.

Identification of four caspase genes from Spodoptera exigua (Lepidoptera: Noctuidae) and their regulations toward different apoptotic stimulations

Apoptosis plays critical roles in multiple biological processes in multicellular organisms. Caspases are known as important participators and regulators of apoptosis. Here, four novel caspase genes of Spodoptera exigua were cloned and characterized, which were designated as SeCasp-1, SeCasp-6, SeCasp-7 and SeCasp-8. Analysis of the putative encoded protein sequences of these SeCasps indicated that SeCasp-1 and SeCasp-7 were possible homologs of executor caspases; SeCasp-8 was a possible homolog of initiator caspases; and SeCasp-6 was a unique caspase of S. exigua that shares low similarity with all the identified insect caspases. Based on baculovirus expression system analyses, SeCasp-1 exhibited similar caspase activity to human caspase-1, -3, -4, -6, -8 and -9; SeCasp-6 presented similar caspase activity to human caspase-2, -3, -4, -6, -8 and -9; SeCasp-7 exhibited similar caspase activity to human caspase-2, -3 and -6; and SeCasp-8 presented similar caspase activity only to human caspase-8. Induction with different chemicals revealed that SeCasp-1 showed extreme upregulation after 24 h in the treated fat body cell line (IOZCAS-Spex-II) of S. exigua. Developmental expression analysis revealed that SeCasp-1 was highly transcribed in the larval stages, while SeCasp-6, SeCasp-7, SeCasp-8 were down-regulated. The in vivo detection of the relative expression levels of SeCasps in S. eixgua larvae inoculated with different pathogens suggested that SeCasp-1 was sensitive to Bacillus thuringiensis infection and that SeCasp-6 was sensitive to baculovirus infection. SeCasp-7 and SeCasp-8 showed slight changes under either in vitro chemical apoptosis induction or in vivo pathogen infection.

RhoA/ROCKs signaling is increased by treatment with TKI-258 and leads to increased apoptosis in SCC-4 oral squamous cell carcinoma cell line

BACKGROUND

This study evaluated the effect of treatment with TKI-258 on apoptosis, involving Rho GTPases and their effectors in SCC-4 cells of oral squamous cell carcinoma.

METHODS

Markers of cell death and apoptosis were analyzed in control and TKI-258-treated SCC-4 cells by flow cytometry. The involvement of Rho GTPases and effectors in the induction of apoptosis by TKI-258 was evaluated by quantification of cleaved PARP. Also, gene expression analysis of those proteins was performed.

RESULTS

The treatment with TKI-258 led to a significant increase in cell death (7-AAD) and apoptosis (annexin V and cleaved PARP). When Rho GTPases were stimulated with LPA and inhibited with toxin A Clostridium difficile, the percentage of apoptotic cells increased and decreased, respectively. A similar effect was found when the treatment was with TKI-258 combined with LPA and toxin A. Treatment with TKI-258 significantly increased RhoA gene expression, while RhoB, RhoC, Rac1, and Cdc42 decreased significantly. ROCKs inhibitors (Y-27632 and HA-1077) reduced apoptosis compared with control. TKI-258 combined with Y-27632 or HA-1077 led to an increase in apoptosis compared with inhibitors only. Treatment with TKI-258 led to an increase in ROCK1 and ROCK2 gene expression, and a decrease in PAK1 and PAK2 gene expression.

CONCLUSIONS

TKI-258 stimulates apoptosis in SCC-4 cells of oral squamous cell carcinoma. Possibly, RhoA GTPase and their effectors ROCKs participate in the signaling pathway inhibited by TKI-258.

CLINICAL RELEVANCE

Therapies with multi-target inhibitors, such as TKI-258, may be promising alternatives for the clinical treatment of oral squamous cell carcinoma.

Identification and functional characterization of three caspases in Takifugu obscurus in response to bacterial infection

Caspases are evolutionarily conserved proteases, which are inextricably linked with the apoptosis and immune system in mammals. However, the expression pattern and function of some caspases remain largely unknown in pufferfish. In this study, three different pufferfish caspases (caspase-2 (Pfcasp-2), caspase-3 (Pfcasp-3), and caspase-8 (Pfcasp-8)) were characterized, and their expression patterns and functions were determined following Aeromonas hydrophila infection. The open reading frames of Pfcasp-2, -3, and -8 are 1,320, 846, and 1455 bp, respectively. Analyses of sequence alignment and phylogenetic tree showed that casp-2, -3, and -8 share 52%-65%, 33%-40%, 63%-78% overall sequence identities with those of other vertebrates, respectively. 3D structures of Pfcasp-2, -3, and -8 enjoy conservation in core area together, while each owns a distinctive profile. Comparisons of deduced amino acid sequences indicated that Pfcaspases possessed the caspase domain and conserved active sites like 'HG' and 'QACXG' (X for R or G). qRT-PCR results revealed that Pfcasp-2, -3, and -8 were expressed constitutively in a wide range of organs, especially in immune-related organs including whole blood and kidney. In vitro, the expressions of the three caspases (Pfcasp-2, 3, and -8) and immune-related genes (IgM and IL-8) were significantly up-regulated in kidney leukocytes after A. Hydrophila challenge and inhibitors treatment. The expressions of Pfcasp-2 and Pfcasp-3 were successfully inhibited in the kidney leukocytes by Ac-DEVD-CHO (an inhibitor to caspase-3), but the expression of Pfcasp-8 was not affected. Cellular localization analysis showed that the distribution of Pfcasp-2, -3, and -8 was in cytoplasm. Further, overexpression of Pfcasp-2, -3, or -8 was found to cause DNA damage and apoptosis, suggesting that three caspases may be related to apoptosis and mediate different apoptosis pathways in pufferfish. Moreover, the expressions of these caspases were also up-regulated in whole blood and kidney after A. hydrophila challenge, indicating their possible involvement in the immune response against A. hydrophia stimulation. Taken together, the results of this study suggest that the caspase-2,-3, and -8 may play an important role in the apoptosis and immune response in pufferfish.

Algae-meditated route to cuprous oxide (Cu2O) nanoparticle: differential expression profile of MALAT1 and GAS5 LncRNAs and cytotoxic effect in human breast cancer

Background

Breast cancer (BC), as the most widely recognized disease in women worldwide, represents about 30% of all cancers impacting women. This study was aimed to synthesize Cu2O nanoparticles from the cystoseira myrica algae (CM-Cu2O NPs) assess their antimicrobial activity against pathogenic bacteria and fungi. We evaluated the expression levels of lncRNAs (MALAT1 and GAS5) and apoptosis genes (p53, p27, bax, bcl2 and caspase3), their prognostic roles.

Methods

In this study, CM-Cu2O NPs synthesized by cystoseira myrica algae extraction used to evaluate its cytotoxicity and apoptotic properties on MDA-MB-231, SKBR3 and T-47D BC cell lines compared to HDF control cell line. The CM-Cu2O NPs was characterized by UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). The antimicrobial activity of CM-Cu2O NPs was assessed against pathogenic bacteria, staphylococcus aureus (S. aureus) PTCC 1112 bacteria as a standard gram-positive bacteria and pseudomonas aeruginosa (P. aeruginosa) PTCC 1310 as a standard gram-negative bacterium. Expression profile of MALAT1 and GAS5 lncRNAs and apoptosis genes, i.e., p27, bax, bcl2 and caspase3 genes, were calculated utilizing qRT-PCR. The changes in the expression levels were determined using the DDCT method.

Results

MALAT1 was upregulated in MDA-MB-231, SKBR3 and T-47D BC (p < 0.01), while GAS5 was downregulated in SKBR3 and T-47D cell lines tested compared with HDF control cell line (p < 0.05) was found. The results revealed that, p27, bax and caspase3 were significantly upregulated in BC cell lines as compared with normal cell line. Bcl2 expression was also significantly increased in MDA-MB-231 and T47D cell lines compared with normal cell line, but bcl2 levels were downregulated in SKBR3 cell line.

Conclusions

Our results confirm the beneficial cytotoxic effects of green-synthesized CM-Cu2O NPs on BC cell lines. This nanoparticle decreased angiogenesis and induces apoptosis, so we conclude that CM-Cu2O NPs can be used as a supplemental drug in cancer treatments. Significantly, elevated circulating lncRNAs were demonstrated to be BC specific and could differentiate BC cell lines from the normal cell lines. It was demonstrated that lncRNAs used in this study and their expression profiles can be created as biomarkers for early diagnosis and prognosis of BC. Further studies utilizing patients would give recognizable identification of lncRNAs as key players in intercellular interactions.

Caspase-Activated Oligonucleotide Probe

Light-activated ("caged") oligonucleotides provide a strategy for modulating the activity of antisense oligos, siRNA, miRNA, aptamers, DNAzymes, and mRNA-capturing probes with high spatiotemporal resolution. However, the near-UV and visible wavelengths that promote these bond-breaking reactions poorly penetrate living tissue, which limits some biological applications. To address this issue, we describe the first example of a protease-activated oligonucleotide probe, capable of reporting on caspase-3 during cellular apoptosis. The 2'-F RNA-peptide substrate-peptide nucleic acid (PNA) hairpin structure was generated in 30% yield in a single bioconjugation step.

Expression and Correlation of Cell-Free cIAP-1 and cIAP-2 mRNA in Breast Cancer Patients: A Study from India

BACKGROUND

Inhibitors of apoptosis proteins such as cIAP-1 and cIAP-2 have recently emerged as the key mechanism in resistance to apoptosis in various cancers and lead to cell survival. Therefore, the present study aimed to evaluate the cIAP-1 and cIAP-2 expression in breast cancer patients, as well as their association with overall patient survival.

METHODS

Histopathologically confirmed 100 invasive ductal carcinoma patients and healthy controls were included in the present study. Total RNA extraction was done from the serum sample of the patients; further, 100 ng of total RNA was used to synthesise cDNA from patients' as well as from healthy controls' serum. Quantitative real-time PCR was performed using the maxima SYBR Green dye to study the expression of cIAP-1 and cIAP-2, and beta-actin was used as the internal control.

RESULTS

The study observed that breast cancer patients had 13.50 mean fold increased cIAP-1 mRNA and 8.76 mean fold increased cIAP-2 mRNA expression compared to the control subjects. Breast cancer patients in the TNM stages I, II, III, and IV showed 9.54, 11.80, 15.19, and 16.83 mean fold increased cIAP-1 mRNA expression (p=0.004). Distant organ metastasis, (p=0.008), PR status of breast cancer patients (p < 0.0001), and HER2 status of breast cancer patients (p < 0.0001) were found to be associated with cIAP-1 mRNA expression. Breast cancer patients with different TNM stages such as stages I, II, III, and IV showed 7.8, 8.09, 7.97, and 12.85 mean fold increased cIAP-2 mRNA expression (p=0.0002). Breast cancer patients with distant organ metastases status were found to be associated with cIAP-2 mRNA expression (p < 0.0001). Breast cancer patients with <13-fold and >13-fold cIAP-1 mRNA expression showed 37.39 months and 34.70 months of overall median survival, and the difference among them was found to be significant (p=0.0001). However, cIAP-2 mRNA expression among <8-fold and >8-fold mRNA expression groups showed 35 months and 27.90 months of overall median survival time (p < 0.0001). Higher cIAP-1 mRNA expression was linked with smoking and alcoholism among the breast cancer patients (p < 0.0001 and p < 0.0001). Significant association of higher cIAP-1 mRNA expression was found with the advancement of the disease, while higher mRNA expression of cIAP-1 was associated with distant organ metastases in ROC curve analysis.

CONCLUSION

The present study suggested that increased cell-free cIAP-1 and cIAP-2 mRNA expression was correlated with the advancement of disease, progression of disease, and overall reduced patient survival. Cell-free cIAP-1 and cIAP-2 mRNA expression could be the predictive indicator of the disease.

Effect of nicotine on placental inflammation and apoptosis in preeclampsia-like model

AIMS

Placental tissues from patients with preeclampsia (PE) and in the lipopolysaccharide (LPS)-induced PE-like model were used to investigate the implication of placental inflammation and apoptosis in PE. Whether the beneficial effects of nicotine are related to inhibition of placental inflammation and apoptosis in the PE-like model were investigated.

MAIN METHODS

Placental apoptosis was detected in PE patients and the PE-like rat model by TUNEL staining. Changes in the number of CD68⁺ macrophages in placental tissues from PE patients were detected by immunofluorescent staining. The mRNA expression of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin (IL-1β), MCP-1, and proteins involved in extrinsic or intrinsic apoptosis signaling in the PE-like model was determined by qRT-PCR; immunofluorescent staining was used to detect the expression of TNF-α receptor (TNFR1), MCP-1 and apoptosis-related proteins.

KEY FINDINGS

Placental apoptosis was increased in both PE patients and the PE-like model, more macrophages infiltrated into placenta in PE patients. A significant upregulation in mRNA expression of TNF-α, IL-1β, MCP-1, and caspase 3, caspase 8, caspase 9 was found in the PE-like rats compared to the control animals, the immunoreactivity of placental MCP-1, TNFR1, and apoptosis-related proteins (caspase 3, caspase 8, caspase 9, Bax) was also enhanced; nicotine treatment significantly reversed those changes.

SIGNIFICANCE

Our data suggests that the protective effects of nicotine are associated with inhibiting placenta inflammation and apoptosis, and nicotine might be a potentially therapeutic candidate for preventing preeclampsia.

Targeting apoptosis in cancer therapy

For over three decades, a mainstay and goal of clinical oncology has been the development of therapies promoting the effective elimination of cancer cells by apoptosis. This programmed cell death process is mediated by several signalling pathways (referred to as intrinsic and extrinsic) triggered by multiple factors, including cellular stress, DNA damage and immune surveillance. The interaction of apoptosis pathways with other signalling mechanisms can also affect cell death. The clinical translation of effective pro-apoptotic agents involves drug discovery studies (addressing the bioavailability, stability, tumour penetration, toxicity profile in non-malignant tissues, drug interactions and off-target effects) as well as an understanding of tumour biology (including heterogeneity and evolution of resistant clones). While tumour cell death can result in response to therapy, the selection, growth and dissemination of resistant cells can ultimately be fatal. In this Review, we present the main apoptosis pathways and other signalling pathways that interact with them, and discuss actionable molecular targets, therapeutic agents in clinical translation and known mechanisms of resistance to these agents.

Magnolol induces human Ewing sarcoma SK-ES-1 cell apoptosis via the mitochondrial and death receptor pathways

New treatments for Ewing's sarcoma (ES) are urgently needed. Magnolol, an active ingredient in Magnolia officinalis, shows anti-oxidative, anti-microbial, and anti-tumor effects, but its effect on ES is unknown. We examined the effect of magnolol on ES cell proliferation and apoptosis in vitro as well as the mechanism of its anticancer effect. The results demonstrated that magnolol inhibited the proliferation of ES and induced ES cell apoptosis through the mitochondrial and death receptor pathways. Magnolol reduced MEK1/2, ERK1/2, and STAT3 phosphorylation in ES cells, suggesting that the MAPK/ERK and JAK/STAT3 signal transduction pathways are involved in the inhibition of ES cell growth by magnolol. In short, magnolol is a potential anti-ES drug.

Structure-based design, synthesis, and evaluation of the biological activity of novel phosphoroorganic small molecule IAP antagonists

One of the strategies employed by novel anticancer therapies is to put the process of apoptosis back on track by blocking the interaction between inhibitor of apoptosis proteins (IAPs) and caspases. The activity of caspases is modulated by the caspases themselves in a caspase/procaspase proteolytic cascade and by their interaction with IAPs. Caspases can be released from the inhibitory influence of IAPs by proapoptotic proteins such as secondary mitochondrial activator of caspases (Smac) that share an IAP binding motif (IBM). The main purpose of the present study was the design and synthesis of phosphorus-based peptidyl antagonists of IAPs that mimic the endogenous Smac protein, which blocks the interaction between IAPs and caspases. Based on the structure of the IAP antagonist and recently reported thiadiazole derivatives, we designed and evaluated the biochemical properties of a series of phosphonic peptides bearing the N-Me-Ala-Val/Chg-Pro-OH motif (Chg: cyclohexylglycine). The ability of the obtained compounds to interact with the binding groove of the X-linked inhibitor of apoptosis protein baculovirus inhibitor of apoptosis protein repeat (XIAP BIR3) domain was examined by a fluorescence polarization assay, while their potential to induce autoubiquitination followed by proteasomal degradation of cellular IAP1 was examined using the MDA-MB-231 breast cancer cell line. The highest potency against BIR3 was observed among peptides containing C-terminal phosphonic phenylalanine analogs, which displayed nanomolar K_i values. Their antiproliferative potential as well as their proapoptotic action, manifested by an increase in caspase-3 activity, was examined using various cell lines.

Reactive oxygen species generation and mitochondrial dysfunction for the initiation of apoptotic cell death in human hepatocellular carcinoma HepG2 cells by a cyclic dipeptide Cyclo(-Pro-Tyr)

Cyclic dipeptides are increasingly gaining importance as considering its significant biological and pharmacological activities. This study was aimed to investigate the anticancer activity of a dipeptide Cyclo(-Pro-Tyr) (DP) identified from marine sponge Callyspongia fistularis symbiont Bacillus pumilus AMK1 and the underlying apoptotic mechanisms in the liver cancer HepG2 cell lines. MTT assay was done to demonstrate the cytotoxic effect of DP in HepG2 cells and mouse Fibroblast McCoy cells. Initially, apoptosis inducing activity of DP was identified using propidium iodide (PI) and acridine orange/ethidium bromide (AO/EB) dual staining, then it was confirmed by DNA fragmentation assay and western blotting analysis of apoptosis related markers Bax, Bcl-2, cytochrome c, caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP). Rhodamine 123 staining was performed to observe DP effects on the mitochondrial membrane potential (MMP) and DCFH-DA (Dichloro-dihydro-fluorescein diacetate) staining was done to measure the intracellular reactive oxygen species (ROS) levels. The MTT results revealed that DP initiated dose-dependent cytotoxicity in HepG2 cells, but no significant toxicity in mouse Fibroblast McCoy cells treated with DP at the specified concentrations. DP induced apoptosis, which is confirmed by the appearance of apoptotic bodies with PI and AO/EB dual staining, and DNA fragmentation. DP significantly elevated the Bax/Bcl-2 ratio, disrupted the mitochondrial membrane potential (MMP), enhanced cytochrome c release from mitochondria, increased caspase-3 activation, the cleavage of PARP and increased intracellular reactive oxygen species (ROS) levels. Besides this, DP successfully inhibited the phosphorylation of PI3K, AKT and increased PTEN expression. These results suggested DP might have anti-cancer effect by initiating apoptosis through mitochondrial dysfunction and downregulating PI3K/Akt signaling pathway in HepG2 cells with no toxicity effect on normal fibroblast cells. Therefore, DP may be developed as a potential alternative therapeutic agent for treating hepatocellular carcinoma.

Granzymes and Mitochondria

Cytotoxic T lymphocytes and natural killer cells eliminate infected cells from the organism by triggering programmed cell death (apoptosis). The contents of the lytic granules of killer cells, including pore-forming proteins perforins and proteolytic enzymes granzymes, are released with the following penetration of the released proteins into the target cells. Granzyme B initiates mitochondria-dependent apoptosis via (i) proapoptotic Bid protein, (ii) Mcl-1 and Bim proteins, or (iii) p53 protein. As a result, cytochrome c is released from the mitochondria into the cytoplasm, causing formation of apoptosomes that initiate the proteolytic cascade of caspase activation. Granzymes M, H, and F cause cell death accompanied by the cytochrome c release from the mitochondria. Granzyme A induces generation of reactive oxygen species (ROS), which promotes translocation of the endoplasmic reticulum-associated SET complex to the nucleus where it is cleaved by granzyme A, leading to the activation of nucleases that catalyze single-strand DNA breaks. Granzymes A and B penetrate into the mitochondria and cleave subunits of the respiratory chain complex I. One of the complex I subunits is also a target for caspase-3. Granzyme-dependent damage to complex I leads to the ROS generation and cell death.

Radiation induced apoptosis and pulmonary fibrosis: curcumin an effective intervention?

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease characterized by interstitial remodeling, leading to compromised lung function. Extra vascular fibrin deposition and abnormalities in the fibrinolysis are the major clinical manifestations of lung diseases such as acute lung injury (ALI) and its most severe form, acute respiratory distress syndrome (ARDS). ALI progresses to pulmonary fibrosis (PF) and makes patient's life miserable. Anti-fibrinolysis and apoptosis are involved in the progression of PF. Apoptotic markers are detectable within IPF lung tissue and senescent cell deletion can rejuvenate pulmonary health. Enhanced expression of p53 due to DNA damage is seen in irradiated lung tissue. The role of fibrinolytic components such as Urokinase Plasminogen activator (uPA), uPA receptor (uPAR) and Plasminogen activator inhibitor-1 (PAI-1) has been detailed in I. Curcumin is known to possess anti-inflammatory and anti-fibrotic effects. Radioprotective effect of curcumin enables it to attenuate radiation-induced inflammation and fibrosis. Understanding the mechanism of radioprotective effect of curcumin in radiation-induced PF and apoptosis can lead to the development of an effective therapeutic to combat acute lung injury and fibrosis.

Genome-wide expression analysis of the heat stress response in dermal fibroblasts of Tharparkar (zebu) and Karan-Fries (zebu × taurine) cattle

The present study sought to evaluate mRNA expression profiles in the cultured dermal fibroblasts of Tharparkar (zebu) and Karan-Fries (zebu, Tharparkar × taurine, Holstein Friesian) cattle in response to heat stress. Bioinformatics' analysis identified temperature-regulated biological processes and pathways. Biological processes overrepresented among the earliest genes induced by temperature stress include regulation of stress responses, protein repair, metabolism, protein transport, cell division, and apoptosis. The present microarray platform contains 51,338 synthesized oligonucleotide probes corresponding to at least 36,713 unigenes. A total of 11,183 and 8126 transcripts were differentially expressed with a fold change of ≥ 2 in Tharparkar and Karan-Fries cattle, respectively. Randomly selected real-time validation showed 83.33% correlation with microarray data. Functional annotation and pathway study of the differentially expressed transcripts or genes (DEGs) reveal that upregulated genes significantly (P < 0.05) affect protein processing and NOD-like receptor pathways (NLRs), while downregulated genes were significantly (P < 0.05) found to be associated with cell cycle, metabolism, and protein transport. Gene expression changes include activation of heat shock factors (HSFs), increased expression of heat shock proteins (HSPs), and apoptosis, while decreasing protein synthesis and another metabolism. These findings provide insights into the underlying mechanism of the physiology of heat stress in Tharparkar and Karan-Fries cattle. Understanding the biology and mechanisms of heat stress is critical to developing approaches to ameliorate current production issues for improving animal performance and agriculture economics in tropical climatic conditions. In conclusion, the present study indicates that heat stress differentially affects the expression of the significant number of genes associated with stress response, metabolism, apoptosis, and protein transport in dermal fibroblasts of Tharparkar and Karan-Fries cattle.

Differential roles of protease isoforms in the tumor microenvironment

Alternative splicing of precursor mRNA is a key mediator of gene expression regulation leading to greater diversity of the proteome in complex organisms. Systematic sequencing of the human genome and transcriptome has led to our understanding of how alternative splicing of critical genes leads to multiple pathological conditions such as cancer. For many years, proteases were known only for their roles as proteolytic enzymes, acting to regulate/process proteins associated with diverse cellular functions. However, the differential expression and altered function of various protease isoforms, such as (i) anti-apoptotic activities, (ii) mediating intercellular adhesion, and (iii) modifying the extracellular matrix, are evidence of their specific contribution towards shaping the tumor microenvironment. Revealing the alternative splicing of protease genes and characterization of their protein products/isoforms with distinct and opposing functions creates a platform to understand how protease isoforms contribute to specific cancer hallmarks. Here, in this review, we address cancer-specific isoforms produced by the alternative splicing of proteases and their distinctive roles in the tumor microenvironment.

Protective effect of hydrogen sulfide on experimental testicular ischemia reperfusion in rats

AIM

Testicular torsion is an urgent urological condition. Ischemia-reperfusion (I/R) processes that occur after detorsion as a treatment for torsion are caused by testicular injury. The purpose of our study is investigating the protecting effect of hydrogen sulfide (H₂S) on the testicular ischemia reperfusion injury.

MATERIALS AND METHODS

Thirty-eight Wistar-Albino rats were divided randomly into 6 different groups: Control (6); sham (6); IR-E (6)-2 h of torsion and 4 h of reperfusion; IR-E + H₂S (6)-in addition to the IR-E group, 75 μmol/kg of sodium hydrogen sulfide (NaHS) was administered intraperitoneally 30 min before reperfusion; IR-L (7)-2 h of torsion and 24 h of reperfusion; IR-L + H₂S (7)-in addition to the IR-L group, 75 μmol/kg NaHS was administered intraperitoneally 30 min before reperfusion. Biochemically, nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), reductive glutathione (GSH), and tumor TNF-α levels were measured in the testis. Serum TNF-α levels were also measured. Hematoxylin and eosin (H & E) was used for histopathological staining and microscopic findings were examined. The Johnsen score was performed to assess spermatogenesis activity in the testis. Apoptosis protease activating factor-1 (Apaf-1) and inducible nitric oxide synthase (iNOS) activity were evaluated immunohistochemically as well. Statistical analyses were made by the Chi-squared test and one-way analysis of variance.

RESULTS

MDA and NO levels were significantly increased in the IR-L group compared with sham and which decreased by the addition of H₂S treatment to the IR-L group (p < 0.05) in biochemical evaluation. GSH vs SOD levels were decreased in the IR-L group compared with sham and which increased by the addition of H₂S treatment to the IR-L group, but this correlations were not statistically significant (p > 0.05). Tissue and serum TNF-α levels were significantly increased in the IR-E group compared with sham and which decreased by the addition of H₂S treatment to the IR-E group. Johnsen score was the lowest in IR-L group (p < 0.05). Apaf-1 and iNOS activity were significantly increased in the IR-L group compared with sham and which decreased by the addition of H₂S treatment to the IR-L group (p < 0.05) in immunohistochemical evaluation.

CONCLUSIONS

First, the authors would like to say that H₂S treatment is protective and it is against ischemia reperfusion injury in testicular torsion. The anti-inflammatory, antioxidant, and antiapoptotic properties of H₂S caused protective effect as shown in this study.

Effect of acute exposure to nitrite on physiological parameters, oxidative stress, and apoptosis in Takifugu rubripes

In the present study, we evaluated the effects of nitrite exposure on hematological parameters, oxidative stress, and apoptosis in juvenile Takifugu rubripes. The fish were exposed to nitrite (0, 0.5, 1, 3, and 6 mM) for up to 96 h. In the high nitrite concentration groups (i.e., 3 and 6 mM), the concentrations of methemoglobin (MetHb), cortisol, glucose, heat shock protein (Hsp)-70, Hsp-90, and potassium (K⁺) were significantly elevated. Whereas, the concentrations of hemoglobin (Hb), triglyceride (TG), total cholesterol (TC), and sodium (Na⁺) and chloride (Cl^-) ions were significantly decreased. Compared with those of the control groups, the concentrations of the antioxidant enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx), in the gills were considerably elevated at 12 and 24 h after exposure to nitrite (1, 3, and 6 mM), but reduced at 48 and 96 h. The increase in the antioxidant enzymes may contribute to the elimination of reactive oxygen species (ROS) induced by nitrite during early nitrite exposure, when the antioxidant system is not sufficiently effective to eliminate or neutralize excessive ROS. In addition, we found that nitrite exposure could alter the expression patterns of some key apoptosis-related genes (Caspase-3, Caspase-8, Caspase-9, p53, Bax, and Bcl-2). This indicated that the caspase-dependent apoptotic pathway and p53-Bax-Bcl-2 pathway might be involved in apoptosis induced by nitrite exposure. Furthermore, our study provides insights into how acute nitrite exposure affects the physiological responses and potential molecular mechanism of apoptosis in marine fish. The results can help elucidate the mechanisms involved in nitrite-induced aquatic toxicology in marine fish.

Activity Dependence of a Novel Lectin Family on Structure and Carbohydrate-Binding Properties

A GalNAc/Gal-specific lectins named CGL and MTL were isolated and characterized from the edible mussels Crenomytilus grayanus and Mytilus trossulus. Amino acid sequence analysis of these lectins showed that they, together with another lectin MytiLec-1, formed a novel lectin family, adopting β-trefoil fold. In this mini review we discuss the structure, oligomerization, and carbohydrate-binding properties of a novel lectin family. We describe also the antibacterial, antifungal, and antiproliferative activities of these lectins and report about dependence of activities on molecular properties. Summarizing, CGL, MTL, and MytiLec-1 could be involved in the immunity in mollusks and may become a basis for the elaboration of new diagnostic tools or treatments for a variety of cancers.

Benzyl Isothiocyanate Induces Apoptosis via Reactive Oxygen Species-Initiated Mitochondrial Dysfunction and DR4 and DR5 Death Receptor Activation in Gastric Adenocarcinoma Cells

Benzyl isothiocyanate (BITC) is known to inhibit the metastasis of gastric cancer cells but further studies are needed to confirm its chemotherapeutic potential against gastric cancer. In this study, we observed cell shrinkage and morphological changes in one of the gastric adenocarcinoma cell lines, the AGS cells, after BITC treatment. We performed 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyl-2H-tetrazolium bromide (MTT) assay, a cell viability assay, and found that BITC decreased AGS cell viability. Reactive oxygen species (ROS) analyses using 2',7'-dichlorofluorescin diacetate (DCFDA) revealed that BITC-induced cell death involved intracellular ROS production, which resulted in mitochondrial dysfunction. Additionally, cell viability was partially restored when BITC-treated AGS cells were preincubated with glutathione (GSH). Western blotting indicated that BITC regulated the expressions of the mitochondria-mediated apoptosis signaling molecules, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and cytochrome c (Cyt c). In addition, BITC increased death receptor DR5 expression, and activated the cysteine-aspartic proteases (caspases) cascade. Overall, our results showed that BITC triggers apoptosis in AGS cells via the apoptotic pathways involved in ROS-promoted mitochondrial dysfunction and death receptor activation.

Investigation of Antibacterial and Antiinflammatory Activities of Proanthocyanidins from Pelargonium sidoides DC Root Extract

The study explores antibacterial, antiinflammatory and cytoprotective capacity of Pelargonium sidoides DC root extract (PSRE) and proanthocyanidin fraction from PSRE (PACN) under conditions characteristic for periodontal disease. Following previous finding that PACN exerts stronger suppression of Porphyromonas gingivalis compared to the effect on commensal Streptococcus salivarius, the current work continues antibacterial investigation on Staphylococcus aureus, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans and Escherichia coli. PSRE and PACN are also studied for their ability to prevent gingival fibroblast cell death in the presence of bacteria or bacterial lipopolysaccharide (LPS), to block LPS- or LPS + IFNγ-induced release of inflammatory mediators, gene expression and surface antigen presentation. Both PSRE and PACN were more efficient in suppressing Staphylococcus and Aggregatibacter compared to Escherichia, prevented A. actinomycetemcomitans- and LPS-induced death of fibroblasts, decreased LPS-induced release of interleukin-8 and prostaglandin E2 from fibroblasts and IL-6 from leukocytes, blocked expression of IL-1β, iNOS, and surface presentation of CD80 and CD86 in LPS + IFNγ-treated macrophages, and IL-1β and COX-2 expression in LPS-treated leukocytes. None of the investigated substances affected either the level of secretion or expression of TNFα. In conclusion, PSRE, and especially PACN, possess strong antibacterial, antiinflammatory and gingival tissue protecting properties under periodontitis-mimicking conditions and are suggestable candidates for treatment of the disease.

Mechanism of a Novel Camptothecin-Deoxycholic Acid Derivate Induced Apoptosis against Human Liver Cancer HepG2 Cells and Human Colon Cancer HCT116 Cells

BACKGROUND

Camptothecin (CPT) is known as an anticancer drug in traditional Chinese medicine. However, due to the lack of targeting, low solubility, and instability of CPT, its therapeutic applications are hampered. Therefore, we synthesized a series of CPT-bile acid analogues that obtained a national patent to improve their tumour-targeting chemotherapeutic effects on liver or colon cancers. Among these analogues, the compound G2 shows high antitumor activity with enhanced liver targeting and improved oral absorption. It is significant to further investigate the possible anticancer mechanism of G2 for its further clinical research and application.

OBJECTIVE

We aimed to unearth the anticancer mechanism of G2 in HepG2 and HCT116 cells.

METHODS

Cell viability was measured using MTT assay; cell cycle, Mitochondrial Membrane Potential (MMP), and cell apoptosis were detected by flow cytometer; ROS was measured by Fluorescent Microplate Reader; the mRNA and protein levels of cell cycle-related and apoptosis-associated proteins were examined by RT-PCR and western blot, respectively.

RESULTS

We found that G2 inhibited cells proliferation of HepG2 and HCT116 remarkably in a dosedependent manner. Moreover, G2-treatment led to S and G2/M phase arrest in both cells, which could be elucidated by the change of mRNA levels of p21, p27 and Cyclin E and the increased protein level of p21. G2 also induced dramatically ROS accumulated and MMP decreased, which contributed to the apoptosis through activation of both the extrinsic and intrinsic pathways via changing the genes and proteins expression involved in apoptosis pathway in both of HepG2 and HCT116 cells.

CONCLUSION

These findings suggested that the apoptosis in both cell lines induced by G2 was related to the extrinsic and intrinsic pathways.

Protective Effects of Aqueous Extract of Mentha suaveolens against Oxidative Stress-Induced Damages in Human Keratinocyte HaCaT Cells

Mentha suaveolens is an aromatic herb that has a wide range of biological activities, including antimicrobial, antifungal, anti-inflammatory, and hepatoprotective properties. Although there are a few reports on the antioxidant property of M. suaveolens, its cytoprotective activity against oxidative stress has not been reported yet. The objective of this study was to determine the protective activity of M. suaveolens aqueous extract (MSAE) against hydrogen peroxide- (H₂O₂-) induced oxidative stress and apoptosis in human keratinocyte HaCaT cells. MSAE pretreatment decreased H₂O₂-induced cytotoxicity and suppressed H₂O₂-induced intracellular ROS generation. Furthermore, MSAE suppressed expression levels of H₂O₂-induced apoptotic genes such as cleaved caspase-3, caspase-9, and cleaved poly (ADP-ribose) polymerase (PARP). Pretreatment with MSAE induced expression of phase II enzyme such as HO-1 through translocation of NF-E2-related factor (Nrf2) upon H₂O₂ exposure. These results revealed that the cytoprotective effect of MSAE against oxidative stress-induced cell death was associated with activation of Nrf2-mediated phase II enzyme expression.

Prospective Application of Activity-Based Proteomic Profiling in Vision Research-Potential Unique Insights into Ocular Protease Biology and Pathology

Activity-based proteomic profiling (ABPP) is a powerful tool to specifically target and measure the activity of a family of enzymes with the same function and reactivity, which provides a significant advantage over conventional proteomic strategies that simply provide abundance information. A number of inherited and age-related eye diseases are caused by polymorphisms/mutations or abnormal expression of proteases including serine proteases, cysteine proteases, and matrix metalloproteinases, amongst others. However, neither conventional genomic, transcriptomic, nor traditional proteomic profiling directly interrogate protease activities. Thus, leveraging ABPP to probe the activity of these enzyme classes as they relate to normal function and pathophysiology of the eye represents a unique potential opportunity for disease interrogation and possibly intervention.

Caspase-mediated cleavage of murine norovirus NS1/2 potentiates apoptosis and is required for persistent infection of intestinal epithelial cells

Human norovirus (HNoV) is the leading cause of acute gastroenteritis and is spread by fecal shedding that can often persist for weeks to months after the resolution of symptoms. Elimination of persistent viral reservoirs has the potential to prevent outbreaks. Similar to HNoV, murine norovirus (MNV) is spread by persistent shedding in the feces and provides a tractable model to study molecular mechanisms of enteric persistence. Previous studies have identified non-structural protein 1 (NS1) from the persistent MNV strain CR6 as critical for persistent infection in intestinal epithelial cells (IECs), but its mechanism of action remains unclear. We now find that the function of CR6 NS1 is regulated by apoptotic caspase cleavage. Following induction of apoptosis in infected cells, caspases cleave the precursor NS1/2 protein, and this cleavage is prevented by mutation of caspase target motifs. These mutations profoundly compromise CR6 infection of IECs and persistence in the intestine. Conversely, NS1/2 cleavage is not strictly required for acute replication in extra-intestinal tissues or in cultured myeloid cells, suggesting an IEC-centric role. Intriguingly, we find that caspase cleavage of CR6 NS1/2 reciprocally promotes caspase activity, potentiates cell death, and amplifies spread among cultured IEC monolayers. Together, these data indicate that the function of CR6 NS1 is regulated by apoptotic caspases, and suggest that apoptotic cell death enables epithelial spread and persistent shedding.

Human Norovirus infection is highly contagious and the most common cause of acute gastroenteritis. Norovirus can be persistently shed after resolution of symptoms, perpetuating or initiating new outbreaks. Murine norovirus (MNV) is also persistently shed, enabling study of host and viral determinants of norovirus pathogenesis. We previously identified a critical role for MNV non-structural protein 1 (NS1), in persistence. Herein we find that regulation of NS1 by host apoptotic caspases is required for infection of intestinal epithelial cells, but not for extra-intestinal spread. Additionally, we demonstrate that NS1 reciprocally promotes cell death and spread among epithelial cells. These data identify regulation of NS1 by host proteases and suggest that apoptotic death is a determinant of epithelial spread and persistence.

Ac2-26 ameliorates lung ischemia-reperfusion injury via the eNOS pathway

BACKGROUND

Lung ischemia-reperfusion injury (LIRI) is a major complication after lung transplantation. Annexin A1 (AnxA1) ameliorates inflammation in various injured organs. This study aimed to determine the effects and mechanism of AnxA1 on LIRI after lung transplantation.

METHODS

Thirty-two rats were randomized into sham, saline, Ac2-26 and Ac2-26/L groups. Rats in the saline, Ac2-26 and Ac2-26/L groups underwent left lung transplantation and received saline, Ac2-26, and Ac2-26/L-NIO, respectively. After 24 h of reperfusion, serum and transplanted lung tissues were examined.

RESULTS

The partial pressure of oxygen (PaO₂) was increased in the Ac2-26 group compared to that in the saline group but was decreased by L-NIO treatment. In the Ac2-26 group, the wet-to-dry (W/D) weight ratios, total protein concentrations, proinflammatory factors and inducible nitric oxide synthase levels were notably decreased, but the concentrations of anti-inflammatory factors and endothelial nitric oxide synthase levels were significantly increased. Ac2-26 attenuated histological injury and cell apoptosis, and this improvement was reversed by L-NIO.

CONCLUSIONS

Ac2-26 reduced LIRI and improved alveoli-capillary permeability by inhibiting oxygen stress, inflammation and apoptosis. The protective effect of Ac2-26 on LIRI largely depended on the endothelial nitric oxide synthase pathway.

Efficient apoptosis requires feedback amplification of upstream apoptotic signals by effector caspase-3 or -7

Apoptosis is a complex multi-step process driven by caspase-dependent proteolytic cleavage cascades. Dysregulation of apoptosis promotes tumorigenesis and limits the efficacy of chemotherapy. To assess the complex interactions among caspases during apoptosis, we disrupted caspase-8, -9, -3, -7, or -6 and combinations thereof, using CRISPR-based genome editing in living human leukemia cells. While loss of apical initiator caspase-8 or -9 partially blocked extrinsic or intrinsic apoptosis, respectively, only combined loss of caspase-3 and -7 fully inhibited both apoptotic pathways, with no discernible effect of caspase-6 deficiency alone or in combination. Caspase-3/7 double knockout cells exhibited almost complete inhibition of caspase-8 or -9 activation. Furthermore, deletion of caspase-3 and -7 decreased mitochondrial depolarization and cytochrome c release upon apoptosis activation. Thus, activation of effector caspase-3 or -7 sets off explosive feedback amplification of upstream apoptotic events, which is a key feature of apoptotic signaling essential for efficient apoptotic cell death.

The first cloned sea cucumber FADD from Holothuria leucospilota: Molecular characterization, inducible expression and involvement of apoptosis

In this study, a sea cucumber Fas-associated death domain (FADD) named HLFADD was first cloned from Holothuria leucospilota. The full-length cDNA of HLFADD is 2137 bp in size, containing a 116-bp 5'-untranslated region (UTR), a 1334-bp 3'-UTR and a 687-bp open reading frame (ORF) encoding a protein of 228 amino acids with a deduced molecular weight of 26.42 kDa. HLFADD protein contains a conserved death effector domain at its N-terminal and a conserved death domain at its C-terminal, structurally similar to its counterparts in vertebrates. The over-expressed HLFADD protein could induce apoptosis in HEK293 cells, suggesting a possible death receptor-mediated apoptosis pathway in echinoderms adapted with FADD. Moreover, HLFADD mRNA is ubiquitously expressed in all examined tissues, with the highest transcript level in the coelomocytes, followed by intestine. In vitro experiments performed in the H. leucospilota coelomocytes, the expression of HLFADD mRNA was significantly up-regulated by lipopolysaccharides (LPS) or polyriboinosinic-polyribocytidylic acid [poly (I:C)] challenge, suggesting that HLFADD might play important roles in the innate immune defense of sea cucumber against the invasion of bacteria and viruses.

Frankincense essential oil suppresses melanoma cancer through down regulation of Bcl-2/Bax cascade signaling and ameliorates heptotoxicity via phase I and II drug metabolizing enzymes

Melanoma is a deadly form of malignancy and according to the World Health Organization 132,000 new cases of melanoma are diagnosed worldwide each year. Surgical resection and chemo/drug treatments opted for early and late stage of melanoma respectively, however detrimental post surgical and chemotherapy consequences are inevitable. Noticeably melanoma drug treatments are associated with liver injuries such as hepatitis and cholestasis which are very common. Alleviation of these clinical manifestations with better treatment options would enhance prognosis status and patients survival. Natural products which induce cytotoxicity with minimum side effects are of interest to achieve high therapeutic efficiency. In this study we investigated anti-melanoma and hepatoprotective activities of frankincense essential oil (FEO) in both in vitro and in vivo models. Pretreatment with FEO induce a significant (p < 0.05) dose-dependent reduction in the cell viability of mouse (B16-F10) and human melanoma (FM94) but not in the normal human epithelial melanocytes (HNEM). Immunoblot analysis showed that FEO induces down regulation of Bcl-2 and up regulation of BAX in B16-F10 cells whereas in FM94 cells FEO induced dose-dependent cleavage of caspase 3, caspase 9 and PARP. Furthermore, FEO (10 μg/ml) treatment down regulated MCL1 in a time-dependent manner in FM94 cells. In vivo toxicity analysis reveals that weekly single dose of FEO (1200 mg/kg body weight) did not elicit detrimental effect on body weight during four weeks of experimental period. Histology of tissue sections also indicated that there were no observable histopathologic differences in the brain, heart, liver, and kidney compare to control groups. FEO (300 and 600 mg/kg body weight) treatments significantly reduced the tumor burden in C57BL/6 mice melanoma model. Acetaminophen (750 mg/kg body weight) was used to induce hepatic injury in Swiss albino mice. Pre treatment with FEO (250 and 500 mg/kg body weight) for seven days retained hematology (complete blood count), biochemical parameters (AST, ALT, ALK, total bilirubin, total protein, glucose, albumin/globulin ratio, cholesterol and triglyceride), and the level of phase I and II drug metabolizing enzymes (cytochrome P450, cytochromeb5, glutathione-S-transferase) which were obstructed by the administration of acetaminophen. Further liver histology showed that FEO treatments reversed the damages (central vein dilation, hemorrhage, and nuclei condensation) caused by acetaminophen. In conclusion, FEO elicited marked anti-melanoma in both in vitro and in vivo with a significant heptoprotection.

Metabolic-hypoxic modulation of cytokine induction of intestinal endothelial adhesion molecules: Relevance to ischemic injury mediated necrotizing enterocolitis?

BACKGROUND

Necrotizing enterocolitis (NEC) triggers an intense inflammatory response in the neonatal gut associated with cytokine activation, altered nutrient status and intracellular O₂-deprivation. Endothelial cell adhesion molecules (ECAMs) play critical roles in driving immune cell infiltration into inflamed gut. Currently, relationships between inflammation, metabolism and ECAM expression remain poorly understood in NEC. We studied the effects of metabolic depletion (aglycemia/ hypoxia) on TNF-α  mediated ECAM expression including ICAM-1, MAdCAM-1, VCAM-1 and E-selectin, in vitro in intestinal microvascular endothelial cells (IMEC).

METHODS

To study the effects of TNF-α, aglycemia and hypoxia (alone or in combination) IMECs expression of adhesion molecules was studied using cell surface ELISA and immunoblotting.

RESULTS

Total VCAM-1 expression was induced TNF-α and by hypoxia + TNF-α, cell surface expression was induced by hypoxia, TNF-α, TNF- α+hypoxia, and TNF- α+hypoxia and aglycemia. Total ICAM-1 increased following TNF- α, TNF- α+hypoxia, hypoxia + aglycemia, and TNF- α+hypoxia + aglycemia. Total MAdCAM-1 protein expression was significantly induced by a combination of TNF-α+hypoxia + aglycemia and cell surface expression induced by TNF- α+hypoxia. Surface expression of E-selectin was induced by TNF- α+aglycemia and TNF- α+hypoxia + aglycemia.

CONCLUSION

Energy metabolism influences inflammation induced injury through mobilization of intestinal ECAMs, and may represent an important mechanism in NEC pathology.

Phaeobacter inhibens induces apoptosis-like programmed cell death in calcifying Emiliania huxleyi

The model coccolithophore, Emiliania huxleyi, forms expansive blooms dominated by the calcifying cell type, which produce calcite scales called coccoliths. Blooms last several weeks, after which the calcified algal cells rapidly die, descending into the deep ocean. E. huxleyi bloom collapse is attributed to E. huxleyi viruses (EhVs) that infect and kill calcifying cells, while other E. huxleyi pathogens, such as bacteria belonging to the roseobacter clade, are overlooked. EhVs kill calcifying E. huxleyi by inducing production of bioactive viral-glycosphingolipids (vGSLs), which trigger algal programmed cell death (PCD). The roseobacter Phaeobacter inhibens was recently shown to interact with and kill the calcifying cell type of E. huxleyi, but the mechanism of algal death remains unelucidated. Here we demonstrate that P. inhibens kills calcifying E. huxleyi by inducing a highly specific type of PCD called apoptosis-like-PCD (AL-PCD). Host death can successfully be abolished in the presence of a pan-caspase inhibitor, which prevents the activation of caspase-like molecules. This finding differentiates P. inhibens and EhV pathogenesis of E. huxleyi, by demonstrating that bacterial-induced AL-PCD requires active caspase-like molecules, while the viral pathogen does not. This is the first demonstration of a bacterium inducing AL-PCD in an algal host as a killing mechanism.

Potential pathological role of pro-inflammatory cytokines (IL-6, TNF-α, and IL-17) in xenotransplantation

The major limitation of organ transplantation is the shortage of available organs from deceased human donors which leads to the deaths of thousands of patients each year. Xenotransplantation is considered to be an effective way to resolve the problem. Immune rejection and coagulation dysfunction are two major hurdles for the successful survival of pig xenografts in primate recipients. Pro-inflammatory cytokines, such as IL-6, TNF-α, and IL-17, play important roles in many diseases and in allotransplantation. However, the pathological roles of these pro-inflammatory cytokines in xenotransplantation remain unclear. Here, we briefly review the signaling transduction and expression regulation of IL-6, TNF-α, and IL-17 and evaluate their potential pathological roles in in vitro and in vivo models of xenotransplantation. We found that IL-6, TNF-α, and IL-17 were induced in most in vitro or in vivo xenotransplantation model. Blockade of these cytokines using gene modification, antibody, or inhibitor had different effects in xenotransplantation. Inhibition of IL-6 signaling with tocilizumab decreased CRP but did not increase xenograft survival. The one possible reason is that tocilizumab can not suppress IL-6 signaling in porcine cells or organs. Other drugs which inhibit IL-6 signaling need to be investigated in xenotransplantation model. Inhibition of TNF-α was beneficial for the survival of xenografts in pig-to-mouse, rat, or NHP models. Blockade of IL-17 using a neutralizing antibody also increased xenograft survival in several animal models. However, the role of IL-17 in the pig-to-NHP xenotransplantation model remains unclear and needs to be further investigated. Moreover, blockade of TNF-α and IL-6 together has got a better effect in pig-to-baboon kidney xenotransplantation. Blockade two or even more cytokines together might get better effect in suppressing xenograft rejection. Better understanding the role of these cytokines in xenotransplantation will be beneficial for choosing better immunosuppressive strategy or producing genetic modification pig.

Efficacy of celastrol combined with cisplatin in enhancing the apoptosis of U-2OS osteosarcoma cells via the mitochondrial and endoplasmic reticulum pathways of apoptosis

Osteosarcoma is a common primary malignant tumor of bone, and the poor prognosis and low 5-year survival rate have not improved for three decades. The present study aimed to study the effect a combination of celastrol and cisplatin on the human osteosarcoma cell line U-2OS, and to investigate the mechanism by which celastrol/cisplatin induces the apoptosis of osteosarcoma cells. MTT and Annexin V-FITC/PI assays were used to evaluate the effects of combined celastrol/cisplatin on growth and apoptosis, respectively, in U-2OS cells. Morphological changes accompanying cell growth inhibition were observed using a fluorescence microscope. Combination index (CI) analysis was used to evaluate the combinatorial effects of celastrol/cisplatin treatment. Western blotting was used to quantify the expression of apoptosis-associated proteins. It was identified that celastrol/cisplatin inhibited the growth of U-2OS cells in a dose-dependent manner. CI analysis revealed that combined celastrol/cisplatin demonstrated a synergistic effect in U-2OS cells, with CIs ranging from 0.80 to 0.97 at effect levels from IC₁₀ to IC₇₀. In addition, it was observed that celastrol/cisplatin upregulated the expression of Bcl-associated X protein, cytochrome c, caspase-3 and C/EBP homologous protein, and downregulated the expression of Bcl-2, poly(ADP-ribose) polymerase, 78 kDa glucose-regulated protein and caspase-9, whereas the expression of caspase-8 remained unchanged. To conclude, celastrol/cisplatin induced apoptosis in U-2OS cells via the mitochondrial and endoplasmic reticulum pathways, particularly in the former. Celastrol/cisplatin therefore exhibits potential as a novel therapeutic combination for the treatment of osteosarcoma.