Apoptosis-associated caspase activation assays

Mechanisms of UV-induced human lymphocyte apoptosis

The article reviews the results of the studies of marker parameters (indicators) of various pathways and mechanisms of apoptosis of lymphocytes in donor peripheral blood induced by UV light (240-390 nm) in doses of 151, 1510, and 3020 J/m2. The article analyses the processes of DNA fragmentation, distortion of the structural asymmetry of the cell membranes, changes in the degree of DNA damage (single-strand breaks), transcriptional factor р53, cytochrome с, Fas receptors (CD95), caspase-3, caspase-8, and caspase-9, reactive oxygen species, and calcium ions in UV modified cells. The study determined that programmed cell death of lymphocytes after UV irradiation with 1510 J/m2 involves the р53-dependent pathway of the nuclear mechanism, as well as receptor-mediated caspase mechanism, mitochondrial mechanism, and the mechanism associated with the defects in calcium homeostasis. Cell death is mediated by reactive oxygen and calcium ions. The article suggests a scheme of possible intracellular events resulting in the apoptotic death of lymphocytes after UV irradiation.

In Vivo Photoacoustic Monitoring of Stem Cell Location and Apoptosis with Caspase-3-Responsive Nanosensors

Stem cell therapy has immense potential in a variety of regenerative medicine applications. However, clinical stem cell therapy is severely limited by challenges in assessing the location and functional status of implanted cells in vivo. Thus, there is a great need for longitudinal, noninvasive stem cell monitoring. Here we introduce a multidisciplinary approach combining nanosensor-augmented stem cell labeling with ultrasound guided photoacoustic (US/PA) imaging for the spatial tracking and functional assessment of transplanted stem cell fate. Specifically, our nanosensor incorporates a peptide sequence that is selectively cleaved by caspase-3, the primary effector enzyme in mammalian cell apoptosis; this cleavage event causes labeled cells to show enhanced optical absorption in the first near-infrared (NIR) window. Optimization of labeling protocols and spectral characterization of the nanosensor in vitro showed a 2.4-fold increase in PA signal from labeled cells during apoptosis while simultaneously permitting cell localization. We then successfully tracked the location and apoptotic status of mesenchymal stem cells in a mouse hindlimb ischemia model for 2 weeks in vivo, demonstrating a 4.8-fold increase in PA signal and spectral slope changes in the first NIR window under proapoptotic (ischemic) conditions. We conclude that our nanosensor allows longitudinal, noninvasive, and nonionizing monitoring of stem cell location and apoptosis, which is a significant improvement over current end-point monitoring methods such as biopsies and histological staining of excised tissue.

Differential regulation of degradation and immune pathways underlies adaptation of the ectosymbiotic nematode Laxus oneistus to oxic-anoxic interfaces

Eukaryotes may experience oxygen deprivation under both physiological and pathological conditions. Because oxygen shortage leads to a reduction in cellular energy production, all eukaryotes studied so far conserve energy by suppressing their metabolism. However, the molecular physiology of animals that naturally and repeatedly experience anoxia is underexplored. One such animal is the marine nematode Laxus oneistus. It thrives, invariably coated by its sulfur-oxidizing symbiont Candidatus Thiosymbion oneisti, in anoxic sulfidic or hypoxic sand. Here, transcriptomics and proteomics showed that, whether in anoxia or not, L. oneistus mostly expressed genes involved in ubiquitination, energy generation, oxidative stress response, immune response, development, and translation. Importantly, ubiquitination genes were also highly expressed when the nematode was subjected to anoxic sulfidic conditions, together with genes involved in autophagy, detoxification and ribosome biogenesis. We hypothesize that these degradation pathways were induced to recycle damaged cellular components (mitochondria) and misfolded proteins into nutrients. Remarkably, when L. oneistus was subjected to anoxic sulfidic conditions, lectin and mucin genes were also upregulated, potentially to promote the attachment of its thiotrophic symbiont. Furthermore, the nematode appeared to survive oxygen deprivation by using an alternative electron carrier (rhodoquinone) and acceptor (fumarate), to rewire the electron transfer chain. On the other hand, under hypoxia, genes involved in costly processes (e.g., amino acid biosynthesis, development, feeding, mating) were upregulated, together with the worm's Toll-like innate immunity pathway and several immune effectors (e.g., bactericidal/permeability-increasing proteins, fungicides). In conclusion, we hypothesize that, in anoxic sulfidic sand, L. oneistus upregulates degradation processes, rewires the oxidative phosphorylation and reinforces its coat of bacterial sulfur-oxidizers. In upper sand layers, instead, it appears to produce broad-range antimicrobials and to exploit oxygen for biosynthesis and development.

Panax notoginseng saponins reduces the cisplatin-induced acute renal injury by increasing HIF-1α/BNIP3 to inhibit mitochondrial apoptosis pathway

Cisplatin (CDDP) may induce apoptosis of renal tubular epithelial cells (RTEC) and cause CDDP-induced acute kidney injury (CAKI) during cancer treatment, but yet lack of preventive measures and effective treatment. As a new Chinese herbal preparation, Panax notoginseng saponins (PNS) has been found to mitigate CDDP-induced CAKI through elevating the expression of HIF-1α in the rat model, according to the data from our previous works. However, the underlying link between HIF-1α and apoptosis has not been well elucidated. The current study as a follow-up work, was aimed to reveal if PNS improves CAKI through HIF-1α-dependent apoptosis. A stably HIF-1α-knockdown human proximal tubular epithelial cell (HK-2) line was established by transfecting a HIF-1α-siRNA into HK-2 cells. Cell viability, mitochondrial function, cell apoptosis ratio and the expression of apoptosis-associated proteins (Cyt C, Bcl2, Bax, caspases 3) were determined. In order to elucidate the underlying mechanism, the expression of HIF-1α and BNIP3 were assessed. Our results showed that treatment of PNS rescued the cell viability of CDDP-injured HK-2 or HIF-1α-knockdown HK-2 cells, and increased the expression levels of ATP and MMP in HK-2 or HIF-1α-knockdown HK-2 cells which were reduced by CDDP. Moreover, PNS treatment decreased the CDDP or CDDP plus HIF-1α-knockdown-induced elevation of apoptosis and apoptosis-associated protein expressions. These findings demonstrate that PNS reduces CAKI through increasing HIF-1α to inhibit mitochondrial apoptosis pathway. Hence, we suggest PNS as a protective and therapeutic new drug for CDDP treatment of cancers, which might have significant meaning of further research and application potential.

Excessive mechanical stretch‑mediated osteoblasts promote the catabolism and apoptosis of chondrocytes via the Wnt/β‑catenin signaling pathway

Excessive biomechanical loading is considered an important cause of osteoarthritis. Although the mechanical responses of chondrocytes and osteoblasts have been investigated, their communication during mechanical loading and the underlying molecular mechanisms are not yet fully known. The present study investigated the effects of excessive mechanically stretched osteoblasts on the metabolism and apoptosis of chondrocytes, and also assessed the involvement of the Wnt/β‑catenin signaling pathway. In the present study, rat chondrocytes and osteoblasts were subjected to mechanical tensile strain, and an indirect chondrocyte‑osteoblast co‑culture model was established. Reverse transcription‑quantitative PCR and western blotting were performed to determine the expression levels of genes and proteins of interest. An ELISA was performed to investigate the levels of cytokines, including matrix metalloproteinase (MMP) 13, MMP 3, interleukin‑6 (IL‑6) and prostaglandin E2 (PG E2), released from osteoblasts. Flow cytometry was performed to detect the apoptosis of chondrocytes exposed to stretched osteoblast conditioned culture medium. The levels of MMP 13, IL‑6 and PG E2 increased significantly in the supernatants of stretched osteoblasts compared with the un‑stretched group. By contrast, the mRNA expression levels of Collagen 1a and alkaline phosphatase were significantly decreased in osteoblasts subjected to mechanical stretch compared with the un‑stretched group. The mRNA expression level of Collagen 2a was significantly decreased, whereas the expression levels of MMP 13 and a disintegrin and metalloproteinase with thrombospondin‑like motifs 5 were significantly increased in chondrocytes subjected to mechanical stretch compared with the un‑stretched group. In the co‑culture model, the results indicated that excessive mechanically stretched osteoblasts induced the catabolism and apoptosis of chondrocytes, which was partly inhibited by Wnt inhibitor XAV‑939. The results of the present study demonstrated that excessive mechanical stretch led to chondrocyte degradation and inhibited osteoblast osteogenic differentiation; furthermore, excessive mechanically stretched osteoblasts induced the catabolism and apoptosis of chondrocytes via the Wnt/β‑catenin signaling pathway.

Hesperidin ameliorates hypobaric hypoxia-induced retinal impairment through activation of Nrf2/HO-1 pathway and inhibition of apoptosis

High-altitude retinopathy is initiated by hypobaric hypoxia and characterized by retinal functional changes, but the precise cellular and molecular mechanisms that mediate this dysfunction remain unclear. The aim of our investigation is to determine the protective efficacy of hesperidin (HSD) on the hypobaric hypoxia-induced damage to the retina. Experiment rats were randomly grouped as the control, hypobaric hypoxia group and HSD intervention group. The hypobaric hypoxia and the HSD intervention groups were maintained in a low-pressure oxygen cabin. We found that hypobaric hypoxia dramatically reduced nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1(HO-1) levels, induced an elevation in immunostaining of TUNEL-positive cells. Hypobaric hypoxia exposure resulted in the increase of Bcl-2, decrease of caspase3 and caspase9 expression as well as Bax level. HSD protected the retina from hypobaric hypoxia-caused impairment by enhancing Nrf2 and HO-1 activation, attenuating apoptotic caspases levels, and reducing Bax and preserving Bcl-2 expression. Additionally, oxidative stress increased poly (ADP-ribose) polymerase 1 (PARP1) and suppressed ciliary neurotrophic factor (CNTF) level, HSD treatment reverted this effect by down-regulation of PARP1 and up-regulation of CNTF expression. Taken together, our findings implicate that HSD exerts a protective role in response to hypobaric hypoxia stress by activating Nrf2/HO-1 pathway and inhibiting apoptosis.

Novel SIRT Inhibitor, MHY2256, Induces Cell Cycle Arrest, Apoptosis, and Autophagic Cell Death in HCT116 Human Colorectal Cancer Cells

We examined the anticancer effects of a novel sirtuin inhibitor, MHY2256, on HCT116 human colorectal cancer cells to investigate its underlying molecular mechanisms. MHY2256 significantly suppressed the activity of sirtuin 1 and expression levels of sirtuin 1/2 and stimulated acetylation of forkhead box O1, which is a target protein of sirtuin 1. Treatment with MHY2256 inhibited the growth of the HCT116 (TP53 wild-type), HT-29 (TP53 mutant), and DLD-1 (TP53 mutant) human colorectal cancer cell lines. In addition, MHY2256 induced G0/G1 phase arrest of the cell cycle progression, which was accompanied by the reduction of cyclin D1 and cyclin E and the decrease of cyclin-dependent kinase 2, cyclin-dependent kinase 4, cyclin-dependent kinase 6, phosphorylated retinoblastoma protein, and E2F transcription factor 1. Apoptosis induction was shown by DNA fragmentation and increase in late apoptosis, which were detected using flow cytometric analysis. MHY2256 downregulated expression levels of procaspase-8, -9, and -3 and led to subsequent poly(ADP-ribose) polymerase cleavage. MHY2256-induced apoptosis was involved in the activation of caspase-8, -9, and -3 and was prevented by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, the autophagic effects of MHY2256 were observed as cytoplasmic vacuolation, green fluorescent protein-light-chain 3 punctate dots, accumulation of acidic vesicular organelles, and upregulated expression level of light-chain 3-II. Taken together, these results suggest that MHY2256 could be a potential novel sirtuin inhibitor for the chemoprevention or treatment of colorectal cancer or both.

Pharmacokinetic Profiles Determine Optimal Combination Treatment Schedules in Computational Models of Drug Resistance

Identification of optimal schedules for combination drug administration relies on accurately estimating the correct pharmacokinetics, pharmacodynamics, and drug interaction effects. Misspecification of pharmacokinetics can lead to wrongly predicted timing or order of treatments, leading to schedules recommended on the basis of incorrect assumptions about absorption and elimination of a drug and its effect on tumor growth. Here, we developed a computational modeling platform and software package for combination treatment strategies with flexible pharmacokinetic profiles and multidrug interaction curves that are estimated from data. The software can be used to compare prespecified schedules on the basis of the number of resistant cells where drug interactions and pharmacokinetic curves can be estimated from user-provided data or models. We applied our approach to publicly available in vitro data of treatment with different tyrosine kinase inhibitors of BT-20 triple-negative breast cancer cells and of treatment with erlotinib of PC-9 non-small cell lung cancer cells. Our approach is publicly available in the form of an R package called ACESO (https://github.com/Michorlab/aceso) and can be used to investigate optimum dosing for any combination treatment. SIGNIFICANCE: These findings introduce a computational modeling platform and software package for combination treatment strategies with flexible pharmacokinetic profiles and multidrug interaction curves that are estimated from data.

Applications of flow cytometry in molluscan immunology: Current status and trends

Flow cytometry (FCM) is routinely used in fundamental and applied research, clinical practice, and clinical trials. In the last three decades, this technique has also become a routine tool used in immunological studies of molluscs to analyse physical and chemical characteristics of haemocytes. Here, we briefly review the current implementation of FCM in the field of molluscan immunology. These applications cover a diverse range of practices from straightforward total cell counts and cell viability to characterize cell subpopulations, and further extend to analyses of DNA content, phagocytosis, oxidative stress and apoptosis. The challenges and prospects of FCM applications in immunological studies of molluscs are also discussed.

Andrastone A From the Deep-Sea-Derived Fungus Penicillium allii-sativi Acts as an Inducer of Caspase and RXRα-Dependent Apoptosis

Two new (1, 2) and one known (3) meroterpenoids were isolated from the deep-sea-derived fungus Penicillium allii-sativi. The relative structures of new compounds were determined on the basis of an extensive analysis of the NMR and MS data, and the absolute configurations were established by ECD calculations. Andrastone A (1) is a rare andrastin bearing an unusual cyclopentan-1,3-dione. It shows a selectively antiproliferative effect against HepG2 tumor cells with an IC50 value of 7.8 μM. Mechanism study showed that apoptosis via Caspase and RXRα pathways are responsible for the inhibitory effect.

N‑acetyl cysteine inhibits lipopolysaccharide‑induced apoptosis of human umbilical vein endothelial cells via the p38MAPK signaling pathway

Lipopolysaccharide (LPS) can regulate the expression of apoptotic factors, including caspase‑3, Bcl‑2 and Bcl‑2‑associated X protein (Bax). Nitric oxide (NO) plays an important role in apoptosis. N‑acetyl cysteine (NAC) has been shown to exhibit antioxidant effects in vitro. However, the effects of NAC on LPS‑induced apoptosis of human umbilical vein endothelial cells (HUVECs) and the associated mechanisms are not well characterized. The present study explored the effect of NAC on LPS‑induced apoptosis of HUVECs and determined the participation of the p38 mitogen‑activated protein kinase (MAPK) pathway in the process of apoptosis. Cell viability was assessed using the Cell Counting Kit‑8 (CCK‑8) assay. The expression of caspase‑3, Bax, Bcl‑2, phosphorylated (p)‑p38MAPK/total (t‑)p38MAPK and p‑endothelial e nitric oxide synthase (eNOS)/t‑eNOS proteins were determined by western blotting. The expression levels of caspase‑3, Bax and Bcl‑2 mRNA were determined using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). The rate of apoptosis was determined using flow cytometry. An NO detection kit (nitric reductase method) was used to determine NO concentration. The results of CCK‑8 and flow cytometric analyses showed that pretreatment of HUVECs with NAC or p38MAPK inhibitor (SB203580) attenuated LPS‑induced decrease in cell viability and increase in cell apoptosis. RT‑qPCR and western blotting showed that LPS promoted caspase‑3 and Bax expression, but inhibited that of Bcl‑2 in HUVECs; however, these effects were attenuated by pretreatment with NAC or SB203580. LPS stimulation significantly enhanced the expression of p‑p38MAPK protein and reduced the expression of p‑eNOS protein; however, these effects were attenuated by pretreatment with NAC or SB203580. NAC pretreatment attenuated LPS‑induced inhibition of NO synthesis, which was consistent with the effects of SB203580. The results demonstrated that NAC pretreatment alleviated LPS‑induced apoptosis and inhibition of NO production in HUVECs. Furthermore, these effects were proposed to be mediated via the p38MAPK signaling pathway.

In Vitro Methods for Assessing Nanoparticle Toxicity

As a consequence of their increase in annual production and widespread distribution in the environment, nanoparticles potentially pose a significant public health risk. The sought-after catalytic activity granted by their physiochemical properties doubles as a hazard to physiological processes following exposure through inhalation, oral, transdermal, subcutaneous, and intravenous uptake. Upon uptake into the body, their size, morphology, surface charge, coating, and chemical composition augment the response of biological systems to the materials and enhance their toxicity. Identification of each property is necessary to predict the harm imposed by foreign nanomaterials in the body. Assay methods ranging from endotoxin and lactate dehydrogenase (LDH) signaling to apoptosis and oxidative stress detection supply valuable techniques for exposing biomarkers of nanoparticle-induced cellular damage. Spectroscopic investigation of epithelial barrier permeation and distribution within living cells reveals the proclivity of nanoparticles to penetrate the body's natural defensive boundaries and deposit themselves in cytotoxic locations. Combination of the various characterization methodologies and assays is required for every new nanoparticulate system despite preexisting data for similar systems due to the lack of deterministic trends among investigated nanoparticles. The propensity of nanomaterials to denature proteins and oxidize substrates in their local environment generates significant concern for the applicability of several traditional in vitro assays, and the modification of susceptible approaches into novel methods suitable for the evaluation of nanoparticles comprises the focus of future work centered on nanoparticle toxicity analysis.

MHY440, a Novel Topoisomerase Ι Inhibitor, Induces Cell Cycle Arrest and Apoptosis via a ROS-Dependent DNA Damage Signaling Pathway in AGS Human Gastric Cancer Cells

We investigated the antitumor activity and action mechanism of MHY440 in AGS human gastric cancer cells. MHY440 inhibited topoisomerase (Topo) Ι activity and was associated with a DNA damage response signaling pathway. It exhibited a stronger anti-proliferative effect on AGS cells relative to Hs27 human foreskin fibroblast cells, and this effect was both time- and concentration-dependent. MHY440 also increased cell arrest in the G2/M phase by decreasing cyclin B1, Cdc2, and Cdc25c, and upregulating p53 and p73. MHY440 induced AGS cell apoptosis through the upregulation of Fas-L, Fas, and Bax as well as the proteolysis of BH3 interacting-domain death agonist and poly(ADP-ribose) polymerase. It also contributed to the loss of mitochondrial membrane potential. The apoptotic cell death induced by MHY440 was inhibited by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor, indicating that apoptosis was caspase-dependent. Moreover, the apoptotic effect of MHY440 was reactive oxygen species (ROS)-dependent, as evidenced by the inhibition of MHY440-induced PARP cleavage and ROS generation via N-acetylcysteine-induced ROS scavenging. Taken together, MHY440 showed anticancer effects by inhibiting Topo I, regulating the cell cycle, inducing apoptosis through caspase activation, and generating ROS, suggesting that MHY440 has considerable potential as a therapeutic agent for human gastric cancer.

Evaluation of In Vitro Antioxidant and Anticancer Properties of the Aqueous Extract from the Stem Bark of Stryphnodendron adstringens

Stryphnodendron adstringens (Mart.) Coville (Fabaceae) is a tree species native to the Brazilian Cerrado commonly known as barbatimão. In traditional medicine, decoctions or infusions of the stem bark of this plant are used in the treatment of several diseases. The objective of this study was to analyze the chemical composition of Stryphnodendron adstringens aqueous extracts (SAAE) prepared from the stem bark to assess their antioxidant activity and anticancer effects as well as characterize cell death mechanisms against murine B16F10Nex-2 melanoma cells. From the SAAE, gallic acid, gallocatechin, epigallocatechin, dimeric and trimeric proanthocyanidins mainly composed of prodelphinidin units and the isomeric chromones C-hexosyl- and O-pentosyl-5,7-dihydroxychromone were identified. The SAAE showed antioxidant activity through direct free-radical scavenging as well as through oxidative hemolysis and lipid peroxidation inhibition in human erythrocytes. Furthermore, SAAE promoted apoptosis-induced cell death in melanoma cells by increasing intracellular reactive oxygen species (ROS) levels, inducing mitochondrial membrane potential dysfunction and activating caspase-3. Together, these data show the antioxidant and anticancer effects of Stryphnodendron adstringens. These results open new perspectives for studies against other tumor cell lines and in vivo models as well as for the identification and isolation of the chemical constituents responsible for these effects.

Synergistic antitumor effect of suberoylanilide hydroxamic acid and cisplatin in osteosarcoma cells

Cisplatin, as a first-line chemotherapy drug, has been widely applied for therapy of osteosarcoma. However, its application is limited by drug resistance and serious side effects, including nephrotoxicity and ototoxicity. Suberoylanilide hydroxamic acid (SAHA) is a newly developed histone deacetylase (HDAC) inhibitor, which is the first Food and Drug Administration-approved HDAC inhibitor for the treatment of cutaneous manifestations of T-cell lymphoma. However, SAHA as a monotherapy was revealed to be limited, particularly in solid tumors. In the present study, 143B osteosarcoma cells were treated with multiple concentrations of SAHA or cisplatin, either alone or combined. The morphological characteristics of the treated cells were observed using an inverted microscope. The cytotoxicity effects of the combination of SAHA and cisplatin on 143B cells were analyzed by MTT assay, colony formation assay, wound healing cell migration assay, cell apoptosis assay and cell cycle analysis. Western blot analysis was performed to detect the protein expression levels of B cell lymphoma-2 (Bcl-2)-associated X protein (Bax), Bcl-2, cleaved-caspase-3, cleaved-caspase-8 and cleaved-poly (ADP-ribose) polymerase (PARP). The experimental data indicated that the inhibition of cell proliferation in the combination group was significantly increased compared with that in single drug groups. Expression levels of pro-apoptotic protein were upregulated, whereas anti-apoptotic Bcl-2 was downregulated significantly in 143B cells following SAHA/cisplatin treatment. Taken together, the results revealed that the combination of SAHA and cisplatin inhibited the proliferation of 143B cells and induced their apoptosis synergistically, and this effectiveness may be mediated by caspase activation.

Sinularin Selectively Kills Breast Cancer Cells Showing G2/M Arrest, Apoptosis, and Oxidative DNA Damage

The natural compound sinularin, isolated from marine soft corals, is antiproliferative against several cancers, but its possible selective killing effect has rarely been investigated. This study investigates the selective killing potential and mechanisms of sinularin-treated breast cancer cells. In 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolium, inner salt (MTS) assay, sinularin dose-responsively decreased the cell viability of two breast cancer (SKBR3 and MDA-MB-231) cells, but showed less effect on breast normal (M10) cells after a 24 h treatment. According to 7-aminoactinomycin D (7AAD) flow cytometry, sinularin dose-responsively induced the G2/M cycle arrest of SKBR3 cells. Sinularin dose-responsively induced apoptosis on SKBR3 cells in terms of a flow cytometry-based annexin V/7AAD assay and pancaspase activity, as well as Western blotting for cleaved forms of poly(ADP-ribose) polymerase (PARP), caspases 3, 8, and 9. These caspases and PARP activations were suppressed by N-acetylcysteine (NAC) pretreatment. Moreover, sinularin dose-responsively induced oxidative stress and DNA damage according to flow cytometry analyses of reactive oxygen species (ROS), mitochondrial membrane potential (MitoMP), mitochondrial superoxide, and 8-oxo-2'-deoxyguanosine (8-oxodG)). In conclusion, sinularin induces selective killing, G2/M arrest, apoptosis, and oxidative DNA damage of breast cancer cells.

miR-98 inhibits cell proliferation and induces cell apoptosis by targeting MAPK6 in HUVECs

The aim of current study was to explore the role of microRNA (miR)-98 in atherosclerosis. Human vascular endothelial cells (HVECs) were isolated from the peripheral blood of healthy volunteers and patients with atherosclerosis. Compared with endothelial cells from the healthy control group, the expression level of mitogen activated protein kinase (MAPK)6 was significantly upregulated and miR-98 was downregulated in the endothelial cells of patients with atherosclerosis. The human umbilical vein endothelial cell line (HUVEC) was adopted to perform in vitro studies. Overexpression of miR-98 reduced the proliferation and induced the apoptosis of HUVECs, which were revealed using an MTT assay, and flow cytometry assay, respectively. The aforementioned influences of miR-98 on HUVECs were mediated by targeting MAPK6, which was verified using luciferase assays. Additionally, the overexpression of miR-98 reduced the protein level of apoptosis regulator Bcl-2 and MAPK6; however, it induced the protein expression of caspase-3 and apoptosis regulator Bax. In conclusion, these findings demonstrate that miR-98 is an important regulator of atherosclerosis, suggesting that miR-98 may be a potential therapeutic target for the treatment of atherosclerosis.

Sinularin induces oxidative stress-mediated G2/M arrest and apoptosis in oral cancer cells

Soft corals-derived natural product, sinularin, was antiproliferative against some cancers but its effect and detailed mechanism on oral cancer cells remain unclear. The subject of this study is to examine the antioral cancer effects and underlying detailed mechanisms in terms of cell viability, oxidative stress, cell cycle analysis, and apoptosis analyses. In MTS assay, sinularin dose-responsively decreased cell viability of three oral cancer cells (Ca9-22, HSC-3, and CAL 27) but only little damage to oral normal cells (HGF-1). This cell killing effect was rescued by the antioxidant N-acetylcysteine (NAC) pretreatment. Abnormal cell morphology and induction of reactive oxygen species (ROS) were found in sinularin-treated oral cancer Ca9-22 cells, however, NAC pretreatment also recovered these changes. Sinularin arrested the Ca9-22 cells at G2/M phase and dysregulated the G2/M regulatory proteins such as cdc2 and cyclin B1. Sinularin dose-responsively induced apoptosis on Ca9-22 cells in terms of flow cytometry (annexin V and pancaspase analyses) and western blotting (caspases 3, 8, 9) and poly (ADP-ribose) polymerase (PARP). These apoptotic changes of sinularin-treated Ca9-22 cells were rescued by NAC pretreatment. Taken together, sinularin induces oxidative stress-mediated antiproliferation, G2/M arrest, and apoptosis against oral cancer cells and may be a potential marine drug for antioral cancer therapy.

Investigating Intracellular Localisation and Cytotoxicity Trends for Neutral and Cationic Iridium Tetrazolato Complexes in Live Cells

A family of five neutral cyclometalated iridium(III) tetrazolato complexes and their methylated cationic analogues have been synthesised and characterised. The complexes are distinguished by variations of the substituents or degree of π conjugation on either the phenylpyridine or tetrazolato ligands. The photophysical properties of these species have been evaluated in organic and aqueous media, revealing predominantly a solvatochromic emission originating from mixed metal-to-ligand and ligand-to-ligand charge transfer excited states of triplet multiplicity. These emissions are characterised by typically long excited-state lifetimes (∼hundreds of ns), and quantum yields around 5-10 % in aqueous media. Methylation of the complexes caused a systematic red-shift of the emission profiles. The behaviour and the effects of the different complexes were then examined in cells. The neutral species localised mostly in the endoplasmic reticulum and lipid droplets, whereas the majority of the cationic complexes localised in the mitochondria. The amount of complexes found within cells does not depend on lipophilicity, which potentially suggests diverse uptake mechanisms. Methylated analogues were found to be more cytotoxic compared to the neutral species, a behaviour that might to be linked to a combination of uptake and intracellular localisation.

Assessment of Drug Sensitivity in Hematopoietic Stem and Progenitor Cells from Acute Myelogenous Leukemia and Myelodysplastic Syndrome Ex Vivo

Current understanding suggests that malignant stem and progenitor cells must be reduced or eliminated for prolonged remissions in myeloid neoplasms such as acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS). Multicolor flow cytometry has been widely used to distinguish stem and myeloid progenitor cells from other populations in normal and malignant bone marrow. In this study, we present a method for assessing drug sensitivity in MDS and AML patient hematopoietic stem and myeloid progenitor cell populations ex vivo using the investigational Nedd8‐activating enzyme inhibitor MLN4924 and standard‐of‐care agent cytarabine as examples. Utilizing a multicolor flow cytometry antibody panel for identification of hematopoietic stem cells, multipotent progenitors, common myeloid progenitors, granulocyte‐monocyte progenitors, and megakaryocyte‐erythroid progenitors present in mononuclear cell fractions isolated from bone marrow aspirates, we compare stem and progenitor cell counts after treatment for 24 hours with drug versus diluent. We demonstrate that MLN4924 exerts a cytotoxic effect on MDS and AML stem and progenitor cell populations, whereas cytarabine has more limited effects. Further application of this method for evaluating drug effects on these populations ex vivo and in vivo may inform rational design and selection of therapies in the clinical setting. Stem Cells Translational Medicine2017;6:840–850

Effects of Hypobaric Hypoxia on Rat Retina and Protective Response of Resveratrol to the Stress

High-altitude retinopathy represents retinal functional changes associated with environmental challenges imposed by hypobaric hypoxia, but the detailed cellular and molecular mechanism underlying this process remains unclear. Our current investigation was to explore the effect of hypobaric hypoxia on the rat retina and determine whether resveratrol has a protective efficacy on the hypoxic damage to the retina. Experiment rats were randomly grouped as the control group, hypoxia group and resveratrol intervention group. The hypoxia group and the resveratrol intervention group were maintained in a low-pressure oxygen cabin, and the resveratrol intervention group was given daily intraperitoneal injections with resveratrol. We found that hypobaric hypoxia increased thioredoxin 1 (Trx1) and thioredoxin 2 (Trx2) expression in retinas, and resveratrol treatment significantly reversed these changes (P < 0.05, P < 0.05 respectively). In comparison with controls, hypoxia upregulated the mRNA expression levels of caspase3 (P < 0.001), caspase9 (P < 0.01), heat shock protein 70 (Hsp70) (P < 0.05), heat shock protein 90 (Hsp90) (P < 0.001) and hypoxia-inducible factor-1 (HIF-1) (P < 0.05). Resveratrol administration caused a significant decrease in the gene expression of caspase3 (P< 0.001), HSP90 (P < 0.05) and HIF-1 mRNA (P < 0.01) as well as an increase in HSP70 mRNA when compared with the hypoxia group. These findings indicated that resveratrol exerted an anti-oxidative role by modulating hypoxia stress- associated genes and an anti-apoptosis role by regulating apoptosis-related cytokines. In conclusion, hypobaric hypoxia may have a pathological impact on rat retinas. The intervention of resveratrol reverses the effect induced by hypobaric hypoxia and elicits a protective response to the stress.

MicroRNA-497 Induces Apoptosis and Suppresses Proliferation via the Bcl-2/Bax-Caspase9-Caspase3 Pathway and Cyclin D2 Protein in HUVECs

INTRODUCTION

MicroRNAs play crucial roles in various types of diseases. However, to date, no information about the role of miR-497 in the development of atherosclerosis has been reported. This study investigated the possible role of miR-497 in vascular endothelial cell injury during the early stage of atherosclerosis.

MATERIALS AND METHODS

The expression level of miR-497 in human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL was detected using qRT-PCR. To perform gain of function and loss of function analyses, miR-497 mimics were transfected into HUVECs, and miR-497 inhibitors were transfected into HUVECs stimulated with ox-LDL. Flow cytometry was used to analyze cell cycle progression and apoptosis. EdU and CCK-8 assays were employed to detect DNA synthesis and cell proliferation, respectively. After bioinformatics prediction, a dual Luciferase Reporter assay was used to analyze the direct target genes of miR-497. The mRNA and protein levels of the target genes were detected using qRT-PCR and western blot analyses, respectively. Caspase-9/3 activity was analyzed to determine the mechanism of endothelial dysfunction.

RESULTS

We showed that miR-497 was significantly upregulated in HUVECs stimulated with ox-LDL. Ectopic expression of miR-497 suppressed cell proliferation, induced apoptosis and increased the activity of caspase-9/3. After verification, Bcl2 and CCND2 were shown to be direct target genes of miR-497 in HUVECs. MiR-497 significantly suppressed cell proliferation by arresting the cell cycle through the CCND2 protein and induced apoptosis through the Bcl2/Bax-caspase9-caspase3 pathway.

CONCLUSION

Overall, our study shows that miR-497 might play a role in the development of atherosclerosis by inducing apoptosis and suppressing the proliferation of vascular endothelial cells. Therefore, miR-497 could be a potential therapeutic target for the treatment of atherosclerosis.

Tenuifolide B from Cinnamomum tenuifolium Stem Selectively Inhibits Proliferation of Oral Cancer Cells via Apoptosis, ROS Generation, Mitochondrial Depolarization, and DNA Damage

The development of drugs that selectively kill oral cancer cells but are less harmful to normal cells still provide several challenges. In this study, the antioral cancer effects of tenuifolide B (TFB), extracted from the stem of the plant Cinnamomum tenuifolium are evaluated in terms of their effects on cancer cell viability, cell cycle analysis, apoptosis, oxidative stress, and DNA damage. Cell viability of oral cancer cells (Ca9-22 and CAL 27) was found to be significantly inhibited by TFB in a dose-responsive manner in terms of ATP assay, yielding IC₅₀ = 4.67 and 7.05 μM (24 h), but are less lethal to normal oral cells (HGF-1). Dose-responsive increases in subG1 populations as well as the intensities of flow cytometry-based annexin V/propidium iodide (PI) analysis and pancaspase activity suggested that apoptosis was inducible by TFB in these two types of oral cancer cells. Pretreatment with the apoptosis inhibitor (Z-VAD-FMK) reduced the annexin V intensity of these two TFB-treated oral cancer cells, suggesting that TFB induced apoptosis-mediated cell death to oral cancer cells. Cleaved-poly (ADP-ribose) polymerase (PARP) and cleaved-caspases 3, 8, and 9 were upregulated in these two TFB-treated oral cancer cells over time but less harmful for normal oral HGF-1 cells. Dose-responsive and time-dependent increases in reactive oxygen species (ROS) and decreases in mitochondrial membrane potential (MitoMP) in these two TFB-treated oral cancer cells suggest that TFB may generate oxidative stress as measured by flow cytometry. N-acetylcysteine (NAC) pretreatment reduced the TFB-induced ROS generation and further validated that ROS was relevant to TFB-induced cell death. Both flow cytometry and Western blotting demonstrated that the DNA double strand marker γH2AX dose-responsively increased in TFB-treated Ca9-22 cells and time-dependently increased in two TFB-treated oral cancer cells. Taken together, we infer that TFB can selectively inhibit cell proliferation of oral cancer cells through apoptosis, ROS generation, mitochondrial membrane depolarization, and DNA damage.

Parallel single-cell analysis of active caspase-3/7 in apoptotic and non-apoptotic cells

Analysing the chemical content of individual cells has already been proven to reveal unique information on various biological processes. Single-cell analysis provides more accurate and reliable results for biology and medicine than analyses of extracts from cell populations, where a natural heterogeneity is averaged. To meet the requirements in the research of important biologically active molecules, such as caspases, we have developed a miniaturized device for simultaneous analyses of individual cells. A stainless steel body with a carousel holder enables high-sensitivity parallel detections in eight microvials. The holder is mounted in front of a photomultiplier tube with cooled photocathode working in photon counting mode. The detection of active caspase-3/7, central effector caspases in apoptosis, in single cells is based on the bioluminescence chemistry commercially available as Caspase-Glo^® 3/7 reagent developed by Promega. Individual cells were captured from a culture medium under microscope and transferred by micromanipulator into detection microvial filled with the reagent. As a result of testing, the limits of detection and quantification were determined to be 0.27/0.86 of active caspase-3/7 content in an average apoptotic cell and 0.46/2.92 for non-apoptotic cells. Application potential of this technology in laboratory diagnostics and related medical research is discussed. Graphical abstract Miniaturized device for simultaneous analyses of individual cells.

Lycium barbarum polysaccharides attenuates N-methy-N-nitrosourea-induced photoreceptor cell apoptosis in rats through regulation of poly (ADP-ribose) polymerase and caspase expression

ETHNOPHARMACOLOGICAL RELEVANCE

Lycium barbarum L., popularly known as "Goji berry", a classic of Traditional Chinese Medicine has long been used to treat ocular diseases and cardiovascular diseases. Recently, the photoreceptor cell protection of Lycium barbarum polysaccharides (LBP), a water extract from Lycium barbarum L. has received more attention. The present study was designed to investigate the effect of LBP on N-methyl-N-nitrosourea (MNU)-induced photoreceptor cell apoptosis, and the involvement of the poly (ADP-ribose) polymerase (PARP) and caspase.

MATERIALS AND METHODS

Photoreceptor cell injury was induced in male Sprague-Dawley rats by an intraperitoneal injection of MNU 60mg/kg. Seven days prior to MNU injection, LBP were intragastrical administered daily, rats were sacrificed at 24h and 7 days after MNU injection. Retinal morphologies, photoreceptor cells apoptosis, and protein expression were evaluated at 24h and 7 days after MNU injection.

RESULTS

Morphologically, the outer nuclear layer was well preserved in the LBP-treated rat retinas throughout the experimental period. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling (TUNEL) assays showed that LBP could significantly suppress the loss of photoreceptor cells, as determined by the photoreceptor cell ratio at the central retina 24h and 7 days after MNU administration. Western-blot analysis demonstrated the expression levels of procaspase-9, -7, -3 and cleaved caspase-9, -7, -3 were upregulated, and PARP were downregulated both 24h and 7 days after MNU injection. LBP treatment significantly decreased protein levels of procaspase and cleaved caspase, increased the level of PARP and cleaved PARP on 24h and 7 days.

CONCLUSIONS

LBP inhibits MNU-induced rat photoreceptor cell apoptosis and protects retinal structure via the regulation of the expressions of PARP and caspase.

Antiproliferation of Cryptocarya concinna-derived cryptocaryone against oral cancer cells involving apoptosis, oxidative stress, and DNA damage

Background

Cryptocarya-derived crude extracts and their compounds have been reported to have an antiproliferation effect on several types of cancers but their impact on oral cancer is less well understood.

Methods

We examined the cell proliferation effect and mechanism of C. concinna-derived cryptocaryone (CPC) on oral cancer cells in terms of cell viability, apoptosis, reactive oxygen species (ROS), mitochondrial depolarization, and DNA damage.

Results

We found that CPC dose-responsively reduced cell viability of two types of oral cancer cells (Ca9-22 and CAL 27) in MTS assay. The CPC-induced dose-responsive apoptosis effects on Ca9-22 cells were confirmed by flow cytometry-based sub-G1 accumulation, annexin V staining, and pancaspase analyses. For oral cancer Ca9-22 cells, CPC also induced oxidative stress responses in terms of ROS generation and mitochondrial depolarization. Moreover, γH2AX flow cytometry showed DNA damage in CPC-treated Ca9-22 cells. CPC-induced cell responses in terms of cell viability, apoptosis, oxidative stress, and DNA damage were rescued by N-acetylcysteine pretreatment, suggesting that oxidative stress plays an important role in CPC-induced death of oral cancer cells.

Conclusions

CPC is a potential ROS-mediated natural product for anti-oral cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1073-5) contains supplementary material, which is available to authorized users.

Peroxisome Proliferator-Activated Receptor Ligands and Their Role in Chronic Myeloid Leukemia: Therapeutic Strategies

Imatinib therapy remains the gold standard for treatment of chronic myeloid leukemia; however, the acquired resistance to this therapeutic agent in patients has urged the scientists to devise modalities for overcoming this chemoresistance. For this purpose, initially therapeutic agents with higher tyrosine kinase activity were introduced, which had the potential for inhibiting even mutant forms of Bcr-Abl. Furthermore, coupling imatinib with peroxisome proliferator-activated receptor ligands also showed beneficial effects in chronic myeloid leukemia cell proliferation. These combination protocols inhibited cell growth and induced apoptosis as well as differentiation in chronic myeloid leukemia cell lines. In addition, peroxisome proliferator-activated receptors ligands increased imatinib uptake by upregulating the expression of human organic cation transporter 1. Taken together, peroxisome proliferator-activated receptors ligands are currently being considered as novel promising therapeutic candidates for chronic myeloid leukemia treatment, because they can synergistically enhance the efficacy of imatinib. In this article, we reviewed the potential of peroxisome proliferator-activated receptors ligands for use in chronic myeloid leukemia treatment. The mechanism of action of these therapeutics modalities are also presented in detail.

Recommendations from the INHAND Apoptosis/Necrosis Working Group

Historically, there has been confusion relating to the diagnostic nomenclature for individual cell death. Toxicologic pathologists have generally used the terms "single cell necrosis" and "apoptosis" interchangeably. Increased research on the mechanisms of cell death in recent years has led to the understanding that apoptosis and necrosis involve different cellular pathways and that these differences can have important implications when considering overall mechanisms of toxicity, and, for these reasons, the separate terms of apoptosis and necrosis should be used whenever differentiation is possible. However, it is also recognized that differentiation of the precise pathway of cell death may not be important, necessary, or possible in routine toxicity studies and so a more general term to indicate cell death is warranted in these situations. Morphological distinction between these two forms of cell death can sometimes be straightforward but can also be challenging. This article provides a brief discussion of the cellular mechanisms and morphological features of apoptosis and necrosis as well as guidance on when the pathologist should use these terms. It provides recommended nomenclature along with diagnostic criteria (in hematoxylin and eosin [H&E]-stained sections) for the most common forms of cell death (apoptosis and necrosis). This document is intended to serve as current guidance for the nomenclature of cell death for the International Harmonization of Nomenclature and Diagnostic Criteria Organ Working Groups and the toxicologic pathology community at large. The specific recommendations are:Use necrosis and apoptosis as separate diagnostic terms.Use modifiers to denote the distribution of necrosis (e.g., necrosis, single cell; necrosis, focal; necrosis, diffuse; etc.).Use the combined term apoptosis/single cell necrosis whenThere is no requirement or need to split the processes, orWhen the nature of cell death cannot be determined with certainty, orWhen both processes are present together. The diagnosis should be based primarily on the morphological features in H&E-stained sections. When needed, additional, special techniques to identify and characterize apoptosis can also be used.

Combination therapy with nitric oxide and molecular hydrogen in a murine model of acute lung injury

Acute lung injury (ALI) is still a leading cause of morbidity and mortality in critically ill patients. Inhaled nitric oxide (NO) has been reported to ameliorate ALI. However, reactive nitrogen species produced by NO can cause lung injury. Because hydrogen gas (H2) is reported to eliminate peroxynitrite, it is expected to reduce the adverse effects of NO. Moreover, we have found that H2 inhalation can attenuate lung injury. Therefore, we hypothesized that combination therapy with NO and H2 might afford more potent therapeutic strategies for ALI. In the present study, a mouse model of ALI was induced by intratracheal administration of lipopolysaccharide (LPS). The animals were treated with inhaled NO (20 ppm), H2 (2%), or NO + H2, starting 5 min after LPS administration for 3 h. We found that LPS-challenged mice exhibited significant lung injury characterized by the deterioration of histopathology and histologic scores, wet-to-dry weight ratio, and oxygenation index (ratio of oxygen tension to inspired oxygen fraction [Pao2/Fio2]), as well as total protein in the bronchoalveolar lavage fluid (BALF), which was attenuated by NO or H2 treatment alone. Combination therapy with NO and H2 had a more beneficial effect with significant interaction between the two. While the nitrotyrosine level in lung tissue was prominent after NO inhalation alone, it was significantly eliminated after breathing a mixture of NO with H2. Furthermore, NO or H2 treatment alone markedly attenuated LPS-induced lung neutrophil recruitment and inflammation, as evidenced by downregulation of lung myeloperoxidase activity, total cells, and polymorphonuclear neutrophils in BALF, as well as proinflammatory cytokines (tumor necrosis factor α, interleukins 1β and 6, and high-mobility group box 1) and chemokines (keratinocyte-derived chemokine, macrophage inflammatory proteins 1α and 2, and monocyte chemoattractant protein 1) in BALF. Combination therapy with NO and H2 had a more beneficial effect against lung inflammatory response. Moreover, combination therapy with NO and H2 could more effectively inhibit LPS-induced pulmonary early and late nuclear factor κB activation as well as pulmonary cell apoptosis. In addition, combination treatment with inhaled NO and H2 could also significantly attenuate lung injury in polymicrobial sepsis. Combination therapy with subthreshold concentrations of NO and H2 still had a significantly beneficial effect against lung injury induced by LPS and polymicrobial sepsis. Collectively, these results demonstrate that combination therapy with NO and H2 provides enhanced therapeutic efficacy for ALI.

Curdione inhibits proliferation of MCF-7 cells by inducing apoptosis

BACKGROUND

Curdione, one of the major components of Curcuma zedoaria, has been reported to possess various biological activities. It thus might be a candidate anti-flammatory and cancer chemopreventive agent. However, the precise molecular mechanisms of action of curdione on cancer cells are still unclear. In this study, we investigated the effect of curdione on breast cancer.

MATERIALS AND METHODS

Xenograft nude mice were used to detect the effect of curdione on breast cancer in vivo; we also tested the effect of curdione on breast cancer in vitro by MTT, Flow cytometry, JC-I assay, and western blot.

RESULTS

Firstly, we found that curdione significantly suppressed tumor growth in a xenograft nude mouse breast tumor model in a dose-dependent manner. In addition, curdione treatment inhibited cell proliferation and induced cell apoptosis. Moreover, after curdione treatment, increase of impaired mitochondrial membrane potential occurred in a concentration dependent manner. Furthermore, the expression of apoptosis-related proteins including cleaved caspase-3, caspase-9 and Bax was increased in curdione treatment groups, while the expression of the anti-apoptotic Bcl-2 was decreased. Inhibitors of caspase-3 were used to confirm that curdione induced apoptosis.

CONCLUSIONS

Overall, our observations first suggested that curdione inhibited the proliferation of breast cancer cells by inducing apoptosis. These results might provide some molecular basis for the anti-cancer activity of curdione.

Apoptotic effects of psiRNA-STAT3 on 4T1 breast cancer cells in vitro

BACKGROUND

The aim of this study was to investigate the effect of a Lipofectamine2000 (Life2000) Transfection Reagent transfected psiRNA-STAT3 plasmid on 4T1 breast cancer cells.

MATERIALS AND METHODS

MTT was used to detect the cell proliferation of breast cancer 4T1 cells at different periods (0h, 6h, 8h, 10h); the cell cycle was assessed by flow cytometry; variation of apoptosis and mitochondrial membrane potential was observed under a fluorescence microscope; immunohistochemical staining was used to determine the expression of caspase-3 and cyclin-D1 protein.

RESULTS

An obvious effect of inhibition to 4T1 cancer cells could be observed at 8h after the psiRNA-STAT3 was transfected. Typical alterations of apoptotic morphological features were visible in the psiRNA-STAT3 treatment group. Mitochondrial membrane potential decreased significantly, the number of cells was increased in G0/G1 phase, and the number of cells was decreased in S phase, and the data were statistically significant (p<0.05), compared with the Scramble and Mock groups. Expression of caspase-3 protein was increased significantly, while that of cyclin D1 was significantly decreased.

CONCLUSIONS

Life2000 transfected psiRNA-STAT3 plasmid can inhibit 4T1 tumor cell proliferation and promote apoptosis of 4T1 tumor cells, which process depends on the regulation of expression of cyclin D1 and caspase-3 protein.

MHY-449, a novel dihydrobenzofuro[4,5-b][1,8]naphthyridin-6-one derivative, mediates oxidative stress-induced apoptosis in AGS human gastric cancer cells

MHY-449 is a novel dihydrobenzofuro[4,5-b][1,8]naphthyridin-6-one derivative designed and synthesized as a potential anticancer agent. The present study aimed to examine the anticancer activity and underlying mechanism of MHY-449. The cell viability assay performed in AGS human gastric carcinoma cells demonstrated that MHY-449 inhibited cell proliferation in a concentration-dependent manner. MHY-449 induced AGS cell death via apoptosis. The underlying molecular mechanism of MHY-449-mediated apoptosis was also investigated. MHY-449 promoted the upregulation of Fas and Fas-ligand, and activation of caspase-8, suggesting the involvement of a Fas-mediated extrinsic pathway in MHY-449-induced apoptosis. In addition, it was found that MHY-449-induced apoptosis was accompanied by the upregulation of Bax, p21(WAF1/CIP1), p27(KIP1), and p53 and suppression of Bcl-2. MHY-449 exposure activated the caspase cascade and subsequent poly(ADP-ribose) polymerase (PARP) cleavage. Furthermore, the pan-caspase inhibitor, Z-VAD-FMK, significantly attenuated MHY-449-induced apoptosis, indicating that the apoptosis was caspase-dependent. Moreover, the apoptogenic effect of MHY-449 was reactive oxygen species (ROS)-dependent. This result was confirmed by the induction of ROS by MHY-449 and by evidence that the scavenging of ROS by N-acetyl-L-cysteine inhibited MHY-449-induced cell death. Taken together, these results demonstrated that MHY-449 triggers apoptosis via caspase activation and ROS production. This result provides a novel mechanistic explanation and a basis for developing this compound as a novel candidate for human cancer therapy.

Nanoparticle-based caspase sensors

Recent advances in nanotechnology have provided new tools for measuring enzymatic activities that are relevant for the assessment of physiological and pathological processes. Caspases, the enzymes intimately linked with cell death and inflammation, are cysteine-dependent aspartate-directed proteases. The measurement of caspase activity requires assays that can provide data with specificity, precision and sensitivity. Several nanoparticle-based assays are now beginning to emerge. This article will first provide a brief discussion of conventional methods of measuring caspase activity and their limitations, followed by an overview of the advantages and limitations of nanoparticle-based strategies for sensing caspase enzymatic activity in vitro and in vivo.

Beneficial effects of hydrogen-rich saline against spinal cord ischemia-reperfusion injury in rabbits

Hydrogen-rich saline (HS) is reported to be a new therapeutic agent in ischemia-reperfusion (I/R)-induced organ damage. The present study was designed to investigate the beneficial effects of HS against spinal cord I/R injury and its associated mechanisms. Spinal cord ischemia was induced by infrarenal aortic occlusion for 20min in male New Zealand white rabbits. Different doses of HS were intravenously (i.v.) administered at 5min before or after the beginning of reperfusion. Moreover, the roles of mitochondrial ATP-sensitive potassium channels (mitoKATP), oxidative stress, inflammatory cytokines and apoptosis was assessed. Here, we found that I/R-challenged rabbits exhibited significant spinal cord injury characterized by the decreased numbers of normal motor neurons and hind-limb motor dysfunction, which was significantly ameliorated by 5mL/kg and 10mL/kg HS treatment before reperfusion or 10mL/kg HS treatment after reperfusion. However, the protective effects of HS treatment in spinal cord I/R injury were partially abolished by the selective mitoKATP channel blocker 5-hydroxydecanoate (5-HD). Moreover, we showed that the beneficial effects of 10mL/kg HS treatment against spinal cord I/R damage were associated with the decreased levels of oxidative products [8-iso-prostaglandin F2α (8-iso-PGF2α) and malondialdehyde (MDA)] and pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1)], as well as the increased activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] in serum at 6h, 12h, 24h, 48h and 72h after reperfusion and in spinal cord at 72h after reperfusion. Furthermore, HS treatment (10mL/kg) reduced caspase-3 activity in the spinal cord of this model. Thus, HS may be an effective therapeutic agent for spinal cord I/R injury via activation of mitoKATP channels as well as reduction of oxidative stress, inflammatory cytokines and apoptosis.

Evaluation of pyroptosis in macrophages using cytosolic delivery of purified flagellin

Pyroptosis is a molecularly controlled form of cell death that exhibits some features of apoptosis as well of necrosis. Pyroptosis is induced by inflammasome-activated caspase-1 or caspase-11 (caspase-4 in humans), as a result of distinct pathogenic or damage stimuli. Although pyroptosis displays some morphological and biochemical features of apoptosis, it has an inflammatory outcome due to the loss of plasma membrane integrity and the consequent release of intracellular contents, reminiscent to necrosis. Here, we use cytosolic delivery of purified flagellin as an experimental tool to trigger pyroptosis and describe potential methods to study this form of cell death. Finally, we discuss the advantages and limitations of these methods.

A novel fluorescence derivatization method combined with HPLC for determining the activities of endogenous caspase

A novel fluorescence derivatization method combined with HPLC was developed to detect the activity of caspase-3 and -8 in two cell lines (Hela cells and A549 cells) which were activated by low temperature-assisted ultraviolet irradiation (LT-UV), mitomycin C (MMC) and camptothecin during the apoptosis, respectively. Two peptide substrates for either caspase-3 or -8 were designed, of which peptide fragments were obtained by enzymatic modification, followed by fluorescence derivatization. A single fluorescent product was formed when a peptide was heated at 120 °C for 10 min in a neutral aqueous medium (pH 7.0) containing catechol, sodium periodate and sodium borate. Commercial kits for detecting the activity of caspase-3 and -8 were used as a control. The relative activity of the caspases detected by fluorescence derivatization was similar to that obtained by commercial kits, which indicated that the novel method is reliable. The activity assays of recombinant human caspases showed that the novel method provided higher selectivity than that of commercial kits, which proved it to be more accurate for determining the activity of caspases in apoptosis.

Molecular hydrogen ameliorates lipopolysaccharide-induced acute lung injury in mice through reducing inflammation and apoptosis

Acute lung injury (ALI) is still a leading cause of morbidity and mortality in critically ill patients. Recently, our and other studies have found that hydrogen gas (H₂) treatment can ameliorate the lung injury induced by sepsis, ventilator, hyperoxia, and ischemia-reperfusion. However, the molecular mechanisms by which H₂ ameliorates lung injury remain unclear. In the current study, we investigated whether H₂ or hydrogen-rich saline (HS) could exert protective effects in a mouse model of ALI induced by intratracheal administration of lipopolysaccharide (LPS) via inhibiting the nuclear factor κB (NF-κB) signaling pathway-mediated inflammation and apoptosis. Two percent of H₂ was inhaled for 1 h beginning at 1 and 6 h after LPS administration, respectively. We found that LPS-challenged mice exhibited significant lung injury characterized by the deterioration of histopathology and histologic scores, wet-to-dry weight ratio, and oxygenation index (PaO₂/FIO₂), as well as total protein in the bronchoalveolar lavage fluid (BALF), which was attenuated by H₂ treatment. Hydrogen gas treatment inhibited LPS-induced pulmonary early and late NF-κB activation. Moreover, H₂ treatment dramatically prevented the LPS-induced pulmonary cell apoptosis in LPS-challenged mice, as reflected by the decrease in TUNEL (deoxynucleotidyl transferase dUTP nick end labeling) staining-positive cells and caspase 3 activity. Furthermore, H₂ treatment markedly attenuated LPS-induced lung neutrophil recruitment and inflammation, as evidenced by downregulation of lung myeloperoxidase activity, total cells, and polymorphonuclear neutrophils in BALF, as well as proinflammatory cytokines (tumor necrosis factor α, interleukin 1β, interleukin 6, and high-mobility group box 1) and chemokines (keratinocyte-derived chemokine, macrophage inflammatory protein [MIP] 1α, MIP-2, and monocyte chemoattractant protein 1) in BALF. In addition, i.p. injection of 10 mL/kg hydrogen-rich saline also significantly attenuated the LPS-induced ALI. Collectively, these results demonstrate that molecular hydrogen treatment ameliorates LPS-induced ALI through reducing lung inflammation and apoptosis, which may be associated with the decreased NF-κB activity. Hydrogen gas may be useful as a novel therapy to treat ALI. munosorbent assay; H₂-hydrogen gas; HMGB1-high-mobility group box 1; HS-hydrogen-rich saline; i.t.-intratracheal; KC-keratinocyte-derived chemokine; LPS-lipopolysaccharide; MCP-1-monocyte chemoattractant protein 1; MIP-1α-macrophage inflammatory protein 1α; MIP-2-macrophage inflammatory protein 2; MPO-myeloperoxidase; PBS-phosphate-buffered saline; PMNs-polymorphonuclear neutrophils; TUNEL-deoxynucleotidyl transferase dUTP nick end labeling; W/D-wet-to-dry.

TNFR1-dependent pulmonary apoptosis during ischemic acute kidney injury

Despite advancements in renal replacement therapy, the mortality rate for acute kidney injury (AKI) remains unacceptably high, likely due to remote organ injury. Kidney ischemia-reperfusion injury (IRI) activates cellular and soluble mediators that incite a distinct pulmonary proinflammatory and proapoptotic response. Tumor necrosis factor receptor 1 (TNFR1) has been identified as a prominent death receptor activated in the lungs during ischemic AKI. We hypothesized that circulating TNF-α released from the postischemic kidney induces TNFR1-mediated pulmonary apoptosis, and we aimed to elucidate molecular pathways to programmed cell death. Using an established murine model of kidney IRI, we characterized the time course for increased circulatory and pulmonary TNF-α levels and measured concurrent upregulation of pulmonary TNFR1 expression. We then identified TNFR1-dependent pulmonary apoptosis after ischemic AKI using TNFR1-/- mice. Subsequent TNF-α signaling disruption with Etanercept implicated circulatory TNF-α as a key soluble mediator of pulmonary apoptosis and lung microvascular barrier dysfunction during ischemic AKI. We further elucidated pathways of TNFR1-mediated apoptosis with NF-κB (Complex I) and caspase-8 (Complex II) expression and discovered that TNFR1 proapoptotic signaling induces NF-κB activation. Additionally, inhibition of NF-κB (Complex I) resulted in a proapoptotic phenotype, lung barrier leak, and altered cellular flice inhibitory protein signaling independent of caspase-8 (Complex II) activation. Ischemic AKI activates soluble TNF-α and induces TNFR1-dependent pulmonary apoptosis through augmentation of the prosurvival and proapoptotic TNFR1 signaling pathway. Kidney-lung crosstalk after ischemic AKI represents a complex pathological process, yet focusing on specific biological pathways may yield potential future therapeutic targets.

Ginkgo May Sensitize Ovarian Cancer Cells to Cisplatin: Antiproliferative and Apoptosis-Inducing Effects of Ginkgolide B on Ovarian Cancer Cells

Ginkgolide B (GB), the primary active component ofGinkgo bilobaextracts, may have antitumor properties. The objective of this study was to determine the effects and possible mechanisms of GB in ovarian cancer cells. In this study, human ovarian cancer cell lines (SKOV3 and CAOV3) were treated with different concentrations of GB alone or in combination with Cis-diaminodichloroplatinum (CDDP). An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to determine cell viability. The apoptosis rates of cells were measured by flow cytometric analysis. The expression of apoptosis-associated and proliferation-associated proteins was detected by Western blot. The cytotoxicity of GB was analyzed using a lactate dehydrogenase assay. Treatment with 100 µM GB for 3 days significantly inhibited SKOV3 and CAOV3 cell proliferation by 57.3% and 63.1% compared with control cells, respectively, as determined by MTT assay. Similarly, the apoptotic cell population was increased when treated with GB in a dose-dependent manner both in SKOV3 and CAOV3 cells. These effects were characterized by the upregulation of p21, p27, cleaved capase-3, and cleaved caspase-8 and downregulation of cyclin D1. In addition, a combined treatment of low concentrations of GB and CDDP showed an additive effect on the inhibition of SKOV3 cell proliferation. Furthermore, GB had significantly less cytotoxicity than CDDP in normal human ovarian surface epithelial cells. This study suggests that GB can be proposed as an effective antiproliferative and apoptosis-inducing agent with interesting translational application in ovarian cancers, used in addition to conventional chemotherapy.

The mechanism of neogambogic acid-induced apoptosis in human MCF-7 cells

Neogambogic acid (NGA), an active ingredient in garcinia, can inhibit the growth of some solid tumors and result in an anticancer effect. We hypothesize that NGA may be responsible for the inhibition of proliferation of human breast cancer cell line MCF-7 cells. To investigate its anticancer mechanism in vitro, MCF-7 cells were treated with various concentrations of NGA. Results of MTT (methyl thiazolyl tetrazolum) assay showed that treatment with NGA significantly reduced the proliferation of MCF-7 cells in a dose-dependent manner. NGA could increase the expression of the apoptosis-related proteins FasL, caspase-3, caspase-8, caspase-9, and Bax and decrease the expression of anti-apoptotic protein Bcl-2 accompanied by the mitochondrial transmembrane damage. The antiproliferative effect of NGA on MCF-7 cells is due to the G(0)/G(1) arrest, increased apoptosis and activation of Fas/FasL and cytochrome C pathway. These results provide an important insight into the cellular and molecular mechanisms through which NGA impairs the proliferation of breast cancer cells.

Effects of PBN and OKN007 in rodent glioma models assessed by 1H MR spectroscopy

Gliomas, the most common primary brain tumors in adults, have a poor outcome. PBN (α-phenyl-tert-butylnitrone) and OKN007 (2,4-disulfophenyl-PBN) are nitrones that have demonstrated beneficial effects in many aging diseases. In this study, we evaluated the anti-tumor effects of PBN and OKN007 in several rodent glioma models (C6, RG2, and GL261) by assessing metabolite alterations with magnetic resonance spectroscopy (MRS). PBN or OKN007 was administered in drinking water before or after tumor formation. MR imaging and single-voxel point-resolved spectroscopy were done to assess tumor morphology and metabolites, after therapy. Major metabolite ratios (choline, N-acetylaspartate, and lipid (methylene or methyl), all compared to creatine), as well as quantification of individual metabolite concentrations, were assessed. Nitrones induced tumor metabolism changes that resulted in restoring major metabolite ratios close to their normal levels, in the glioma regression phase. Nitrone treatment decreased the lipid (methylene)-to-creatine ratio, as well as the estimated concentration of lipid (methylene) significantly. Alterations in lipids can be a useful marker for the evaluation of the efficacy associated with treatment and were found in this study to be related to the reduction of necrosis, but not apoptosis. OKN007 was more effective than PBN when administered after tumor formation in the C6 glioma model. In conclusion, (1)H MRS and conventional MRI are useful methods to assess and follow the response of varied glioma models to anti-tumor treatments.

Beneficial effects of hydrogen gas against spinal cord ischemia-reperfusion injury in rabbits

Recently, hydrogen gas (H₂) is reported to be a new therapeutic agent in organ damage induced by ischemia-reperfusion (I/R). The present study was designed to investigate the beneficial effects of H₂ against spinal cord I/R injury and its associated mechanisms. Spinal cord ischemia was induced by infrarenal aortic occlusion for 20 min in male New Zealand white rabbits. Treatment with 1%, 2% or 4% H₂ inhalation was given from 10 min before reperfusion to 60 min after reperfusion (total 70 min). Here, we found that I/R-challenged animals showed significant spinal cord damage characterized by the decreased numbers of normal motor neurons and hind-limb motor dysfunction, which was significantly improved by 2% and 4 % H₂ treatment. Furthermore, we found that the beneficial effects of H₂ treatment against spinal cord I/R injury were associated with the decreased levels of oxidative products [8-iso-prostaglandin F2α (8-iso-PGF2α) and malondialdehyde (MDA)] and pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1)], as well as increased activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] in serum and spinal cord. In addition, H₂ treatment reduced motor neuron apoptosis in the spinal cord of this model. Thus, H₂ inhalation may be an effective therapeutic strategy for spinal cord I/R damage.

Resistance to caspase-8 and -9 fragments in a malignant pleural mesothelioma cell line with acquired cisplatin-resistance

Apoptotic cysteine–aspartate proteases (caspases) are essential for the progression and execution of apoptosis, and detection of caspase fragmentation or activity is often used as markers of apoptosis. Cisplatin (cis-diamminedichloroplatinum (II)) is a chemotherapeutic drug that is clinically used for the treatment of solid tumours. We compared a cisplatin-resistant pleural malignant mesothelioma cell line (P31res1.2) with its parental cell line (P31) regarding the consequences of in vitro acquired cisplatin-resistance on basal and cisplatin-induced (equitoxic and equiapoptotic cisplatin concentrations) caspase-3, -8 and -9 fragmentation and proteolytic activity. Acquisition of cisplatin-resistance resulted in basal fragmentation of caspase-8 and -9 without a concomitant increase in proteolytic activity, and there was an increased basal caspase-3/7 activity. Similarly, cisplatin-resistant non-small-cell lung cancer cells, H1299res, had increased caspase-3 and -9 content compared with the parental H1299 cells. In P31 cells, cisplatin exposure resulted in caspase-9-mediated caspase-3/7 activation, but in P31res1.2 cells the cisplatin-induced caspase-3/7 activation occurred before caspase-8 or -9 activation. We therefore concluded that in vitro acquisition of cisplatin-resistance rendered P31res1.2 cells resistant to caspase-8 and caspase-9 fragments and that cisplatin-induced, initiator-caspase independent caspase-3/7 activation was necessary to overcome this resistance. Finally, the results demonstrated that detection of cleaved caspase fragments alone might be insufficient as a marker of caspase activity and ensuing apoptosis induction.