CD95(APO-1/Fas)-mediated apoptosis: live and let die

Porcine γδ T cells express cytotoxic cell-associated markers and display killing activity but are not selectively cytotoxic against PRRSV- or swIAV-infected macrophages

Background

Gamma-delta (γδ) T cells are a major immune cell subset in pigs. Approximately 50% of circulating T cells are γδ T cells in young pigs and up to 30% in adult sows. Despite this abundance, the functions of porcine γδ T cells are mostly unidentified. In humans and mice, activated γδ T cells exhibit broad innate cytotoxic activity against a wide variety of stressed, infected, and cancerous cells through death receptor/ligand-dependent and perforin/granzyme-dependent pathways. However, so far, it is unknown whether porcine γδ T cells have the ability to perform cytotoxic functions.

Methods

In this study, we conducted a comprehensive phenotypic characterization of porcine γδ T cells isolated from blood, lung, and nasal mucosa. To further analyze the cytolytic potential of γδ T cells, in vitro cytotoxicity assays were performed using purified γδ T cells as effector cells and virus-exposed or mock-treated primary porcine alveolar macrophages as target cells.

Results

Our results show that only CD2+ γδ T cells express cytotoxic markers (CD16, NKp46, perforin) with higher perforin and NKp46 expression in γδ T cells isolated from lung and nasal mucosa. Moreover, we found that γδ T cells can exhibit cytotoxic functions in a cell-cell contact and degranulation-dependent manner. However, porcine γδ T cells did not seem to specifically target Porcine Reproductive and Respiratory Syndrome Virus or swine Influenza A Virus-infected macrophages, which may be due to viral escape mechanisms.

Conclusion

Porcine γδ T cells express cytotoxic markers and can exhibit cytotoxic activity in vitro. The specific mechanisms by which porcine γδ T cells recognize target cells are not fully understood but may involve the detection of cellular stress signals.

Abnormal biomarkers predict complex FAS or FADD defects missed by exome sequencing

BACKGROUND

Elevated TCRαβ+CD4-CD8- double-negative T cells (DNT) and serum biomarkers help identify FAS mutant patients with autoimmune lymphoproliferative syndrome (ALPS). However, in some patients with clinical features and biomarkers consistent with ALPS, germline or somatic FAS mutations cannot be identified on standard exon sequencing (ALPS-undetermined: ALPS-U).

OBJECTIVE

We sought to explore whether complex genetic alterations in the FAS gene escaping standard sequencing or mutations in other FAS pathway-related genes could explain these cases.

METHODS

Genetic analysis included whole FAS gene sequencing, copy number variation analysis, and sequencing of FAS cDNA and other FAS pathway-related genes. It was guided by FAS expression analysis on CD57+DNT, which can predict somatic loss of heterozygosity (sLOH).

RESULTS

Nine of 16 patients with ALPS-U lacked FAS expression on CD57+DNT predicting heterozygous "loss-of-expression" FAS mutations plus acquired somatic second hits in the FAS gene, enriched in DNT. Indeed, 7 of 9 analyzed patients carried deep intronic mutations or large deletions in the FAS gene combined with sLOH detectable in DNT; 1 patient showed a FAS exon duplication. Three patients had reduced FAS expression, and 2 of them harbored mutations in the FAS promoter, which reduced FAS expression in reporter assays. Three of the 4 ALPS-U patients with normal FAS expression carried heterozygous FADD mutations with sLOH.

CONCLUSION

A combination of serum biomarkers and DNT phenotyping is an accurate means to identify patients with ALPS who are missed by routine exome sequencing.

Elevated temperature triggers increase in global DNA methylation, 5-methylcytosine expression levels, apoptosis and NOx levels in the gonads of Atlantic sea urchin

Global warming is one of the greatest threats to living organisms. Among them, marine invertebrates are severely impacted on reproductive fitness by rising seawater surface temperatures due to climate change (e.g., massive heat waves). In this study, we used highly sensitive radioimmunoassay, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), in situ TUNEL assay, luminescence assay, and colorimetric assay techniques to investigate the impacts of high temperatures on global DNA methylation, cellular apoptosis, and nitrative stress in gonads of Atlantic sea urchin (Arbacia punctulata, a commercially important species). Young adult sea urchins were exposed to 24, 28, and 32 °C for one week in a controlled laboratory setting. High temperatures (28 and 32 °C) markedly increased global DNA methylation (around 1.1-1.5-fold in testes and ~ 1.7-fold in ovaries) and 5-methylcytosine (5-mC) levels in gonads (around 2.7- to ~5.1-fold in ovaries and ~ 3.5- to ~6.2-fold in testes) compared with controls (24 °C). The number of apoptotic nuclei in gonads was much higher in high-temperature groups. The caspase activity also increased significantly (P < 0.05) in gonads in high-temperature groups. Nitrate/nitrites (NOx, a biomarker of reactive nitrogen species) levels were increased around 2.6- to ~5.2-fold in testes and ~ 1.9- to ~3.8-fold in ovaries in high-temperature groups. Collectively, these outcomes indicate that high temperatures drastically induce global DNA methylation, 5-mC expression levels, cellular apoptosis, and NOx levels in the gonads of Atlantic sea urchin.

7-Methoxyheptaphylline Enhances TRAIL-induced Apoptosis of Colorectal Adenocarcinoma Cell via JNK-mediated DR5 Expression

A cytokine known as TNF-related apoptosis-inducing ligand (TRAIL) has the ability to precisely cause the death of cancer cells, while normal cells are left undisturbed. Recent studies show that certain cancer cells are sensitive to the apoptotic effect of TRAIL. In this study, HT29 colorectal adenocarcinoma cells exposed to TRAIL were treated with heptaphylline and 7-methoxyheptaphylline from Clausena harmandiana in an effort to comprehend the mechanisms involved behind this activity. The MTT test was utilized to determine cell survival, and phase contrast microscopy was used to examine cell morphology. Through using real-time RT-PCR, Western blotting, and RT-PCR, the molecular mechanisms were investigated. According to the findings, whilst hepataphylline caused cytotoxicity in normal colon FHC cells, in comparison to healthy colon FHC cells, 7-methoxyheptaphylline inhibited cancer cells in a concentration-dependent manner. Heptaphylline alone or in conjunction with TRAIL showed no discernible effect on TRAL-induced HT29 cell death, but 7-methoxyheptaphylline boosted caspase-3 cleavage. The study showed that the JNK pathway was responsible for the 7-methoxyheptaphylline's enhancement of the DR5 (death receptor 5) mRNA, TRAIL receptor, and protein. The results demonstrated that the 7-methoxyheptaphylline of Clausena harmandiana increased the expression of DR5 via the JNK pathway, intensifying TRAIL-induced HT29 cell death.

Identification of zona pellucida defects revealed a novel loss-of-function mutation in ZP2 in humans and rats

Introduction

Human zona pellucida (ZP) plays an important role in reproductive process. Several rare mutations in the encoding genes (ZP1, ZP2, and ZP3) have been demonstrated to cause women infertility. Mutations in ZP2 have been reported to cause ZP defects or empty follicle syndrome. We aimed to identify pathogenic variants in an infertile woman with a thin zona pellucida (ZP) phenotype and investigated the effect of ZP defects on oocyte gene transcription.

Methods

We performed whole-exome sequencing and Sanger sequencing of genes were performed for infertilite patients characterized by fertilization failure in routine in vitro fertilization (IVF). Immunofluorescence (IF) and intracytoplasmic sperm injection (ICSI) were used in the mutant oocytes. Single-cell RNA sequencing was used to investigate transcriptomes of the gene-edited (Zp2mut/mut) rat model. Biological function enrichment analysis, quantitative real-time PCR (qRT-PCR), and IF were performed.

Results

We identified a novel homozygous nonsense mutation of ZP2 (c.1924C > T, p.Arg642X) in a patient with non-consanguineous married parents. All oocytes showed a thin or no ZP under a light microscope and were fertilized after ICSI. The patient successfully conceived by receiving the only two embryos that developed to the blastocyst stage. The immunofluorescence staining showed an apparently abnormal form of the stopped oocytes. We further demonstrated a total of 374 differentially expressed genes (DEGs) in the transcriptome profiles of Zp2mut/mut rats oocytes and highlighted the signal communication between oocytes and granulosa cells. The pathway enrichment results of DEGs showed that they were enriched in multiple signaling pathways, especially the transforming growth factor-β (TGF-β) signaling pathway in oocyte development. qRT-PCR, IF, and phosphorylation analysis showed significantly downregulated expressions of Acvr2b, Smad2, p38MAPK, and Bcl2 and increased cleaved-caspase 3 protein expression.

Discussion

Our findings expanded the known mutational spectrum of ZP2 associated with thin ZP and natural fertilization failure. Disruption of the integrity of the ZP impaired the TGF-β signaling pathway between oocytes and surrounding granulosa cells, leading to increased apoptosis and decreased developmental potential of oocytes.

Functions and underlying mechanisms of lncRNA HOTAIR in cancer chemotherapy resistance

Chemotherapy has been one of the most important treatments for advanced cancer in recent decades. Although the sensitivity rate of initial chemotherapy is high, patients with chemotherapy resistant tumors, experience tumor recurrence. In recent years, many studies have shown that homeobox transcript antisense intergenic RNA (HOTAIR) is involved in many pathological processes including carcinogenesis. The abnormal regulation of a variety of cell functions by HOTAIR, such as apoptosis, the cell cycle, epithelial-mesenchymal transition, autophagy, self-renewal, and metabolism, is associated with chemotherapy resistance. Therefore, there is an urgent need to understand the biology and mechanism underlying the role of HOTAIR in tumor behavior and its potential as a biomarker for predicting the effect of chemotherapy. In this manuscript, we review the mechanisms underlying HOTAIR-related drug resistance and discuss the limitations of current knowledge and propose potential future directions.

Epigenetic drug ameliorated type 1 diabetes via decreased generation of Th1 and Th17 subsets and restoration of self-tolerance in CD4+ T cells

Female NOD mice develop autoimmune diabetes spontaneously without extrinsic manipulation. Previously, we have shown that weekly administration of the prediabetic female NOD mice with the histone modifier Trichostatin A (TSA) prevented diabetes onset. Herein we show that T lymphocytes from diabetic mice transferred diabetes into immunodeficient NOD.scid recipients while those isolated from drug-treated mice displayed reduced disease-causing ability. Drug treatment also repressed T cell receptor-mediated IFN-γ transcription. Splenic CD4⁺ T-cells purified from prediabetic mice could be polarized into IFN-γ -producing Th1 and IL-17A-expressing Th17 subsets ex vivo. Adoptive transfer of these cells into immunocompromised NOD.scid mice caused diabetes comparably. Polarized Th1 cells were devoid of IL-17A-producing cells and did not transdifferentiate into Th17 cells in the spleen of immunodeficient recipients. However, polarized Th17 cell preparation had a few contaminant Th1 cells. Adoptive transfer of polarized Th17 cells into NOD.scid recipients led to IFN-γ transcription in recipient splenocytes. Notably, TSA treatment of prediabetic mice abolished the ability of CD4⁺ T-cells to differentiate into diabetogenic Th1 and Th17 cells ex vivo. This was accompanied by the absence of Ifng and Il17a transcription in the spleen of NOD.scid recipients receiving cells, respectively cultured under Th1 and Th17 polarizing conditions. Significantly, the histone modifier restored the ability of CD4⁺ but not CD8⁺ T-cells to undergo CD3-mediated apoptosis ex vivo in a caspase-dependent manner. These results indicate that the histone modifier bestowed protection against type 1 diabetes via negative regulation of signature lymphokines and restitution of self-tolerance in CD4⁺ T cells.

Somatic Mutations and Autoimmunity

Autoimmune diseases are among the most common chronic illness caused by a dysregulated immune response against self-antigens. Close to 5% of the general population in Western countries develops some form of autoimmunity, yet its underlying causes, although intensively studied, are still not fully known, and no curative therapies exist. It is well established that autoimmune diseases have common mechanisms and are caused by both genetic and non-genetic risk factors. One novel risk factor that can contribute to autoimmunity is somatic mutations, in a role parallel to their role in cancer. Somatic mutations are stochastic, de novo, non-inherited mutations. In this hypothesis, the persistent proliferation of self-reactive lymphocytes (that is usually hindered by a series of checkpoints) is permitted, due to somatic mutations in these expanding cells, allowing them to bypass multiple regulatory checkpoints, causing autoimmunity. This novel concept of the contribution of these mutations in non-malignant diseases has recently started to be explored. It proposes a novel paradigm for autoimmunity etiology and could be the missing piece of the autoimmunity puzzle.

Fas, Caspase-8, and Caspase-9 pathway-mediated bile acid-induced fetal cardiomyocyte apoptosis in intrahepatic cholestasis pregnant rat models

AIM

Intrahepatic cholestasis of pregnancy (ICP) is a specific complication in the middle and late pregnancy and has been recognized as one of the high-risk pregnancy for sudden fetal death. In this study, we aimed to investigate the role of Fas, Caspase-8, and Caspase-9 pathways in the internal relations of fetal myocardial apoptosis in ICP rat models, thus resulting in fetal intrauterine death. Furthermore, we researched whether ursodeoxycholic acid (UDCA) promoted benefits in fetal cardiomyocyte apoptosis.

MATERIALS AND METHODS

To establish ICP rat models, on the 15th day of pregnancy, rats were injected 17α-ethynyl estradiol (EE2). Meanwhile, in experimental group, pregnant rats were treated with EE2 + UDCA. All rats were sacrificed on the 21st day of pregnancy. The expression levels of Fas, Caspase-8, and Caspase-9 were examined by western blot and real-time polymerase chain reaction analysis. Fetal rat cardiac tissues were removed and stained for pathological evaluation. In addition, we observed fetal myocardial structure by using transmission electron microscopy.

RESULTS

We detected high concentrations of bile acids and transaminase in the fetal circulation. And we found increased expression levels of Fas, Caspase-8, and Caspase-9 proteins and mRNA in the fetal cardiomyocyte in EE2-treated group but not in control- or EE2 + UDCA-treated groups. Furthermore, compared to controls, EE2-treated rats exhibited severe fetal myocardial structure damage and the apoptotic bodies by using transmission electron microscopy. UDCA reversed the impairment of fetal cardiomyocytes.

CONCLUSION

Our study has led to research into the association between activation of Fas, Caspase-8, and Caspase-9 pathways and bile acid-induced fetal cardiomyocyte apoptosis, which may be one of the mechanisms on fetal cardiac death in ICP. More importantly, UDCA may improve the adverse outcome of fetus.

Immunologic evaluation and genetic defects of apoptosis in patients with autoimmune lymphoproliferative syndrome (ALPS)

Apoptosis plays an important role in controlling the adaptive immune response and general homeostasis of the immune cells, and impaired apoptosis in the immune system results in autoimmunity and immune dysregulation. In the last 25 years, inherited human diseases of the Fas-FasL pathway have been recognized. Autoimmune lymphoproliferative syndrome (ALPS) is an inborn error of immunity, characterized clinically by nonmalignant and noninfectious lymphoproliferation, autoimmunity, and increased risk of lymphoma due to a defect in lymphocyte apoptosis. The laboratory hallmarks of ALPS are an elevated percentage of T-cell receptor αβ double negative T cells (DNTs), elevated levels of vitamin B12, soluble FasL, IL-10, IL-18 and IgG, and defective in vitro Fas-mediated apoptosis. In order of frequency, the genetic defects associated with ALPS are germinal and somatic ALPS-FAS, ALPS-FASLG, ALPS-CASP10, ALPS-FADD, and ALPS-CASP8. Partial disease penetrance and severity suggest the combination of germline and somatic FAS mutations as well as other risk factor genes. In this report, we summarize human defects of apoptosis leading to ALPS and defects that are known as ALPS-like syndromes that can be clinically similar to, but are genetically distinct from, ALPS. An efficient genetic and immunological diagnostic approach to patients suspected of having ALPS or ALPS-like syndromes is essential because this enables the establishment of specific therapeutic strategies for improving the prognosis and quality of life of patients.

SUV39H1 regulates human colon carcinoma apoptosis and cell cycle to promote tumor growth

Trimethylation of histone 3 lysine 9 (H3K9me3) at gene promoters is a major epigenetic mechanism that silences gene expression. We have developed a small molecule inhibitor for the H3K9me3-specific histone methyltransferase SUV39H1. We report here that FAS expression is significantly down-regulated and SUV39H1 expression is significantly up-regulated in human colorectal carcinoma (CRC) as compared to normal colon. SUV39H1-selective inhibitor F5446 decreased H3K9me3 deposition at the FAS promoter, increased Fas expression, and increased CRC cell sensitivity to FasL-induced apoptosis in vitro. Furthermore, inhibition of SUV39H1 altered the expression of genes with known functions in DNA replication and cell cycle in the metastatic colon carcinoma cells, which is associated with cell cycle arrest at S phase in the metastatic human colon carcinoma cells, resulting in tumor cell apoptosis and growth inhibition in a concentration-dependent manner in vitro. Moreover, F5446 increased 5-FU-resistant human CRC sensitivity to both 5-FU- and FasL-induced apoptosis and inhibited tumor cell growth in vitro. More importantly, F5446 suppressed human colon tumor xenograft growth in vivo. Our data indicate that pharmacological inhibition of SUV39H1 is an effective approach to suppress human CRC.

Histone Modifications as Biomarkers for Immunotherapy

Recent advances in immunotherapy have revolutionized the treatment of certain cancers. Some patients show a durable response to these immunotherapies, while others show little benefit or develop resistance. Identification of biomarkers to predict responsiveness will be helpful for informing treatment strategies; and would furthermore lead to the identification of molecular pathways dysregulated in nonresponding patients that could be targeted for therapeutic development. Pathways of epigenetic modification, such as histone posttranslational modifications (PTMs), have been shown to be dysregulated in certain cancer and immune cells. Histones are abundant cellular proteins readily assayed with high-throughput technologies, making them attractive targets as biomarkers. We explore promising advancements for using histone PTMs as immunotherapy responsiveness biomarkers in both cancer and immune cells, and provide a methodological workflow for assaying histone PTMs in relevant samples.

The volatile anesthetic sevoflurane reduces neutrophil apoptosis via Fas death domain-Fas-associated death domain interaction

Sepsis remains a significant health care burden, with high morbidities and mortalities. Patients with sepsis often require general anesthesia for procedures and imaging studies. Knowing that anesthetic drugs can pose immunomodulatory effects, it would be critical to understand the impact of anesthetics on sepsis pathophysiology. The volatile anesthetic sevoflurane is a common general anesthetic derived from ether as a prototype. Using a murine sepsis model induced by cecal ligation and puncture surgery, we examined the impact of sevoflurane on sepsis outcome. Different from volatile anesthetic isoflurane, sevoflurane exposure significantly improved the outcome of septic mice. This was associated with less apoptosis in the spleen. Because splenic apoptosis was largely attributed to the apoptosis of neutrophils, we examined the effect of sevoflurane on FasL-induced neutrophil apoptosis. Sevoflurane exposure significantly attenuated apoptosis. Sevoflurane did not affect the binding of FasL to the extracellular domain of Fas receptor. Instead, in silico analysis suggested that sevoflurane would bind to the interphase between Fas death domain (DD) and Fas-associated DD (FADD). The effect of sevoflurane on Fas DD-FADD interaction was examined using fluorescence resonance energy transfer (FRET). Sevoflurane attenuated FRET efficiency, indicating that sevoflurane hindered the interaction between Fas DD and FADD. The predicted sevoflurane binding site is known to play a significant role in Fas DD-FADD interaction, supporting our in vitro and in vivo apoptosis results.-Koutsogiannaki, S., Hou, L., Babazada, H., Okuno, T., Blazon-Brown, N., Soriano, S. G., Yokomizo, T., Yuki, K. The volatile anesthetic sevoflurane reduces neutrophil apoptosis via Fas death domain-Fas-associated death domain interaction.

Promotion of TRAIL/Apo2L-induced apoptosis by low-dose interferon-β in human malignant melanoma cells

Interferon β (IFN-β) is considered a signaling molecule with important therapeutic potential in cancer since IFN-β-induced gene transcription mediates antiproliferation and cell death induction. Whereas, TNF-related apoptosis inducing ligand/Apo2 ligand (TRAIL/Apo2L) has emerged as a promising anticancer agent because it induces apoptosis specifically in cancer cells. In this study, we elucidated that IFN-β augments TRAIL-induced apoptosis synergistically using five human malignant melanoma cells. All of these cells were induced apoptosis by TRAIL. Whereas, the response against IFN-β was different in amelanotic cells (A375 and CRL1579) and melanotic cells (G361, SK-MEL-28, and MeWo). The responsibility of amelanotic cells against IFN-β was higher than those of melanotic cells. The synergism of IFN-β and TRAIL were correlated with the responsibilities of the cells against IFN-β. The synergistic interaction was confirmed by a combination index based on the Chou-Talalay method. The upregulation of apoptosis in amelanotic cells was caused by very low doses of IFN-β (over 0.1 IU/ml). Both of p53-mediated intrinsic pathway and Fas-related extrinsic pathway were activated by IFN-β alone and combination with TRAIL. Further, TRAIL death receptors (DR4 and DR5) were upregulated by a low-dose IFN-β (over 0.1 IU/ml) and the expression was more promoted by the combination with TRAIL. It was clarified that the upregulation of DR5 is associated with the declination of viability.

Comparison of the effects of three kinds of IgYs, (normal, nanoliposomal and nanoparticle conjugated), which are produced against the small domains of DR5 protein on cancer cells

Cancer treatment with several kinds of drugs, especially targets the apoptotic pathways nowadays. TNF-related apoptosis-inducing ligand (TRAIL) as one of the important members of death receptors, significantly trigger induction of apoptosis in cancer cells. Three conserved domains of Death receptor (DR5) protein extracellular domain, which are fortified cysteine, were chosen and chemically synthesised. Hens were immunised with nano-liposomal peptides, and as a result the purified Immunoglobulin (IgYs) remarkably killed the cancerous MCF7 cells. The flow cytometric assay, confirmed the apoptotic death. Among several kinds of carriers that were used in this research, the nano-liposomal and nanoparticle conjugated, both were acceptable choices for drug delivery. Furthermore, the IgY against DR5's small peptides with such carriers successfully reached the target and significantly killed the cancer cells via apoptosis.

The Significance of Tumor Necrosis Factor Receptor Type II in CD8+ Regulatory T Cells and CD8+ Effector T Cells

Tumor necrosis factor (TNF) is a pleiotropic cytokine that has both pro-inflammatory and anti-inflammatory functions. The biological functions of TNF are mediated by two receptors, TNF receptor type I (TNFR1) and TNF receptor type II (TNFR2). TNFR1 is expressed universally on almost all cell types and has been extensively studied, whereas TNFR2 is mainly restricted to immune cells and some tumor cells and its role is far from clarified. Studies have shown that TNFR2 mediates the stimulatory activity of TNF on CD4⁺Foxp3⁺ regulatory T cells (Tregs) and CD8⁺Foxp3⁺ Tregs, and is involved in the phenotypic stability, proliferation, activation, and suppressive activity of Tregs. TNFR2 can also be expressed on CD8⁺ effector T cells (Teffs), which delivers an activation signal and cytotoxic ability to CD8⁺ Teffs during the early immune response, as well as an apoptosis signal to terminate the immune response. TNFR2-induced abolition of TNF receptor-associated factor 2 (TRAF2) degradation may play an important role in these processes. Consequently, due to the distribution of TNFR2 and its pleiotropic effects, TNFR2 appears to be critical to keeping the balance between Tregs and Teffs, and may be an efficient therapeutic target for tumor and autoimmune diseases. In this review, we summarize the biological functions of TNFR2 expressed on CD8⁺Foxp3⁺ Tregs and CD8⁺ Teffs, and highlight how TNF uses TNFR2 to coordinate the complex events that ultimately lead to efficient CD8⁺ T cell-mediated immune responses.

Small Interfering RNA-Mediated Suppression of Fas Modulate Apoptosis and Proliferation in Rat Intervertebral Disc Cells

Study Design

In vitro cell culture model.

Purpose

To investigate the effect of small interfering RNA (siRNA) on Fas expression, apoptosis, and proliferation in serum-deprived rat disc cells.

Overview of Literature

Synthetic siRNA can trigger an RNA interference (RNAi) response in mammalian cells and precipitate the inhibition of specific gene expression. However, the potential utility of siRNA technology in downregulation of specific genes associated with disc cell apoptosis remains unclear.

Methods

Rat disc cells were isolated and cultured in the presence of either 10% fetal bovine serum (FBS) (normal control) or 0% FBS (serum deprivation to induce apoptosis) for 48 hours. Fas expression, apoptosis, and proliferation were determined. Additionally, siRNA oligonucleotides against Fas (Fas siRNA) were transfected into rat disc cells to suppress Fas expression. Changes in Fas expression were assessed by reverse transcription-polymerase chain reaction and semiquantitatively analyzed using densitometry. The effect of Fas siRNA on apoptosis and proliferation of rat disc cells were also determined. Negative siRNA and transfection agent alone (Mock) were used as controls.

Results

Serum deprivation increased apoptosis by 40.3% (p<0.001), decreased proliferation by 45.3% (p<0.001), and upregulated Fas expression. Additionally, Fas siRNA suppressed Fas expression in serum-deprived cultures, with 68.5% reduction at the mRNA level compared to the control cultures (p<0.001). Finally, Fas siRNA–mediated suppression of Fas expression significantly inhibited apoptosis by 9.3% and increased proliferation by 21% in serum-deprived cultures (p<0.05 for both).

Conclusions

The observed dual positive effect of Fas siRNA might be a powerful therapeutic approach for disc degeneration by suppression of harmful gene expression.

Genistein: Its role in metabolic diseases and cancer

Genistein is an isoflavone present in soy and is known to have multiple molecular effects, such as the inhibition of inflammation, promotion of apoptosis, and modulation of steroidal hormone receptors and metabolic pathways. Since these molecular effects impact carcinogenesis, cancer propagation, obesity, osteoporosis, and metabolic syndromes, genistein plays an important role in preventing and treating common disorders. The role of genistein has not been adequately evaluated in all these clinical settings. This review summarizes some of the known molecular effects of genistein and its potential role in health maintenance and treatment.

Anti-c-Met antibody bioconjugated with hollow gold nanospheres as a novel nanomaterial for targeted radiation ablation of human cervical cancer cell

Radiotherapy is preferred to chemotherapy as an adjuvant therapy for postoperative cervical cancer owing to its convenience and minimal effects on various non-targeted systems. The present study sought to investigate whether the utilization of anti-MET proto-oncogene, receptor tyrosine kinase (c-Met) antibodies conjugated to hollow gold nanospheres (anti-c-Met/HGNs) may enhance the efficiency of radiation therapy for cervical cancer. Anti-c-Met/HGNs were synthesized and confirmed to target c-Met, which was overexpressed on the cell membrane of multiple malignancies. The successful synthesis of HGNs was observed using transmission electron microscopy (TEM). Overrepresentation of c-Met in the human cervical cancer cell line CaSki was verified by immunofluorescence. The cellular uptake of HGNs was assessed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). To assess the toxicity of functionalized gold nanospheres, a cell proliferation and toxicity assay was used and flow cytometry, with staining by propidium iodide (PI), was performed to study the cell cycle changes. Each experiment was conducted on three groups: Control, HGNs alone and anti-c-Met/HGNs, with each group also assessed with or without X-rays. The variation of apoptotic rate was observed by flow cytometry using a dual-staining Annexin V-fluorescein isothiocyanate/PI kit. Expression of apoptosis-associated proteins was examined by western blot analysis. TEM revealed a number of hollow spheres with cells with an average diameter of 56.25 nm and a mean wall thickness of 6.56 nm. CaSki cells were detected by inverted fluorescence microscopy via a layer of fluorescent green marker, and ICP-AES confirmed the distinct uptake of anti-c-Met/HGNs by each CaSki cell. Anti-c-Met/HGNs induced 38.7% of cells to stay in the G2/M phase, whereas the equivalent proportion in the control group was 19.8%. Compared with other groups, CaSki cells treated with anti-c-Met/HGNs and 5 Gy X-ray radiation exhibited a higher apoptosis rate (16.92%) and a higher early apoptotic rate (12.30%) compared with cells under other conditions (control+0 Gy: 3.16 and 1.69%; HGN+0 Gy: 3.98 and 1.94%; anti-c-Met/HGN+0 Gy: 3,47 and 1.85%; control+5 Gy: 5.35 and 3.66%; HGN+5 Gy: 7.91 and 4.06%). The anti-c-Met/HGN X-ray-treated group also evidently overexpressed caspase-3 and BCL2 associated X, apoptosis regulator. Anti-c-Met/HGN may, therefore, aid the sensitivity of radiation therapy in cervical cancer.

Correlation of the expression of YY1 and Fas cell surface death receptor with apoptosis of peripheral blood mononuclear cells, and the development of multiple organ dysfunction in children with sepsis

Multiple organ dysfunction (MOD) is a lethal complication in children with sepsis. Apoptosis of several cell types is involved in this process, and it is associated with increased Fas cell surface death receptor (Fas) expression. As YY1 transcription factor (YY1) negatively regulates the expression of Fas in cancer models, and is associated with the clinical outcome, it may be important in MOD. The present study aimed to determine the association between the expression of Fas, YY1 and apoptosis in children with sepsis, and its association with MOD, these factors were analyzed in 30 pediatric patients that had been diagnosed with sepsis. Peripheral blood mononuclear cells were purified from patients, and YY1 and Fas protein expression was assessed by immunocytochemistry. Apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling. Sepsis was monitored using clinical parameters, pediatric logistic organ dysfunction (PELOD) score and the pediatric mortality index. The results demonstrated that Fas expression was directly correlated with apoptosis levels and the expression of YY1 was inversely correlated with apoptosis levels. Patients with high levels of apoptosis exhibited increased disease severity and poor clinical outcome. Notably, the findings of the present study demonstrated that there were higher survival rates in patients with high YY1 expression, compared with those with low YY1 expression. Additionally, patients with MOD exhibited lower proportions of apoptotic cells compared with sepsis patients without MOD. Furthermore, the PELOD score was positively correlated with Fas and inversely correlated with YY1 expression. Finally, high apoptosis and low YY1 expression were prognostic factors associated with poor survival rates. These data suggested that YY1 may be important for apoptosis induction via the regulation of Fas during sepsis. Therefore, Fas may be a potential therapeutic target to prevent MOD through regulation of YY1 expression. Furthermore, YY1 and Fas expression in PBMCs may be used to as prognostic markers.

TNF superfamily cytokines in the promotion of Th9 differentiation and immunopathology

The tumor necrosis factor (TNF) receptors and their corresponding cytokine ligands have been implicated in many aspects of the biology of immune functions. TNF receptors have key roles during various stages of T cell homeostasis. Many of them can co-stimulate lymphocyte proliferation and cytokine production. Additionally, several TNF cytokines can regulate T cell differentiation, including promoting Th1, Th2, Th17, and more recently the newly described Th9 subset. Four TNF family cytokines have been identified as regulators for IL-9 production by T cells. OX40L, TL1A, and GITRL can promote Th9 formation but can also divert iTreg into Th9, while 4-1BBL seems to inhibit IL-9 production from iTreg and has not been studied for its ability to promote Th9 generation. Regulation of IL-9 production by TNF family cytokines has repercussions in vivo, including enhancement of anti-tumor immunity and immunopathology in allergic lung and ocular inflammation. Regulating T cell production of IL-9 through blockade or agonism of TNF family cytokine receptors may be a therapeutic strategy for autoimmune and allergic diseases and in tumor.

The role and regulation of apoptosis in sepsis

Today, sepsis continues to be a growing problem in the critically ill patient population. A number of laboratories have been interested in understanding how changes in immune cell apoptosis during sepsis appear to contribute to septic morbidity. Consistently, it has been found that immune cell apoptosis is altered in a variety of tissue sites and cell populations both in experimental animals and humans. While divergent mediators, such as steroids and TNF, contribute to some of these apoptotic changes, their effects are tissue and cell population selective. Inhibition of FasL—Fas signaling (by either FasL gene deficiency, in vivo gene silencing [siRNA] or with FasL binding protein) protects septic mice from the onset of marked apoptosis and the morbidity/mortality seen in sepsis. Further, this extrinsic apoptosis response appears to utilize aspects of the Bid-induced mitochondrial pathway. This is in keeping with the findings that pan-specific caspase inhibition or the overexpression of Bcl-2 also protect these animals from the sequellae of sepsis.

Ceramide mediates FasL-induced caspase 8 activation in colon carcinoma cells to enhance FasL-induced cytotoxicity by tumor-specific cytotoxic T lymphocytes

FasL-mediated cytotoxicity is one of the mechanisms that CTLs use to kill tumor cells. However, human colon carcinoma often deregulates the Fas signaling pathway to evade host cancer immune surveillance. We aimed at testing the hypothesis that novel ceramide analogs effectively modulate Fas function to sensitize colon carcinoma cells to FasL-induced apoptosis. We used rational design and synthesized twenty ceramide analogs as Fas function modulators. Five ceramide analogs, IG4, IG7, IG14, IG17, and IG19, exhibit low toxicity and potent activity in sensitization of human colon carcinoma cells to FasL-induced apoptosis. Functional deficiency of Fas limits both FasL and ceramide analogs in the induction of apoptosis. Ceramide enhances FasL-induced activation of the MAPK, NF-κB, and caspase 8 despite induction of potent tumor cell death. Finally, a sublethal dose of several ceramide analogs significantly increased CTL-mediated and FasL-induced apoptosis of colon carcinoma cells. We have therefore developed five novel ceramide analogs that act at a sublethal dose to enhance the efficacy of tumor-specific CTLs, and these ceramide analogs hold great promise for further development as adjunct agents in CTL-based colon cancer immunotherapy.

Regulation of PERK-eIF2α signalling by tuberous sclerosis complex-1 controls homoeostasis and survival of myelinating oligodendrocytes

Tuberous sclerosis complex-1 or 2 (TSC1/2) mutations cause white matter abnormalities, including myelin deficits in the CNS; however, underlying mechanisms are not fully understood. TSC1/2 negatively regulate the function of mTOR, which is required for oligodendrocyte differentiation. Here we report that, unexpectedly, constitutive activation of mTOR signalling by Tsc1 deletion in the oligodendrocyte lineage results in severe myelination defects and oligodendrocyte cell death in mice, despite an initial increase of oligodendrocyte precursors during early development. Expression profiling analysis reveals that Tsc1 ablation induces prominent endoplasmic reticulum (ER) stress responses by activating a PERK–eIF2α signalling axis and Fas–JNK apoptotic pathways. Enhancement of the phospho-eIF2α adaptation pathway by inhibition of Gadd34-PP1 phosphatase with guanabenz protects oligodendrocytes and partially rescues myelination defects in Tsc1 mutants. Thus, TSC1-mTOR signalling acts as an important checkpoint for maintaining oligodendrocyte homoeostasis, pointing to a previously uncharacterized ER stress mechanism that contributes to hypomyelination in tuberous sclerosis.

The molecular mechanisms regulating myelination are only partially understood. Here authors show that Tsc1 ablation in oligodendrocyte lineage activates ER stress and apoptotic programs in mice, and that enhancing PERK-eIF2α signalling partially rescues the myelination defects in Tsc1 mutants.

The contribution of apoptosis and necrosis in freezing injury of sea urchin embryonic cells

Sea urchins have recently been reported to be a promising tool for investigations of oxidative stress, UV light perturbations and senescence. However, few available data describe the pathway of cell death that occurs in sea urchin embryonic cells after cryopreservation. Our study is focused on the morphological and functional alterations that occur in cells of these animals during the induction of different cell death pathways in response to cold injury. To estimate the effect of cryopreservation on sea urchin cell cultures and identify the involved cell death pathways, we analyzed cell viability (via trypan blue exclusion test, MTT assay and DAPI staining), caspase activity (via flow cytometry and spectrophotometry), the level of apoptosis (via annexin V-FITC staining), and cell ultrastructure alterations (via transmission electron microscopy). Using general caspase detection, we found that the level of caspase activity was low in unfrozen control cells, whereas the number of apoptotic cells with activated caspases rose after freezing-thawing depending on cryoprotectants used, also as the number of dead cells and cells in a late apoptosis. The data using annexin V-binding assay revealed a very high apoptosis level in all tested samples, even in unfrozen cells (about 66%). Thus, annexin V assay appears to be unsuitable for sea urchin embryonic cells. Typical necrotic cells with damaged mitochondria were not detected after freezing in sea urchin cell cultures. Our results assume that physical cell disruption but not freezing-induced apoptosis or necrosis is the predominant reason of cell death in sea urchin cultures after freezing-thawing with any cryoprotectant combination.

Functional genetics-directed identification of novel pharmacological inhibitors of FAS- and TNF-dependent apoptosis that protect mice from acute liver failure

shRNA-mediated gene-silencing technology paired with cell-based functional readouts reveals potential targets directly, providing an opportunity to identify drugs against the target without knowing the precise role of the target in the pathophysiological processes of interest. By screening a lentiviral shRNA library targeting for major components of human signaling pathways and known drug targets, we identified and validated both canonical as well as 52 novel mediators of FAS and TNF ligand-induced apoptosis. Presence of potential therapeutic targets among these mediators was confirmed by demonstration of in vivo activity of siRNAs against four identified target candidates that protected mice from acute liver failure (ALF), a life-threatening disease with known involvement of death receptor (DR)-mediated apoptosis. Network-based modeling was used to predict small-molecule inhibitors for several candidate apoptosis mediators, including somatostatin receptor 5 (SSTR5) and a regulatory subunit of PP2A phosphatase, PPP2R5A. Remarkably, pharmacological inhibition of either SSTR5 or PPP2R5A reduced apoptosis induced by either FASL or TNF in cultured cells and dramatically improved survival in several mouse models of ALF. These results demonstrate the utility of loss-of-function genetic screens and network-based drug-repositioning methods for expedited identification of targeted drug candidates and revealed pharmacological agents potentially suitable for treatment of DR-mediated pathologies.

Research Advances on Pathways of Nickel-Induced Apoptosis

High concentrations of nickel (Ni) are harmful to humans and animals. Ni targets a number of organs and produces multiple toxic effects. Apoptosis is important in Ni-induced toxicity of the kidneys, liver, nerves, and immune system. Apoptotic pathways mediated by reactive oxygen species (ROS), mitochondria, endoplasmic reticulum (ER), Fas, and c-Myc participate in Ni-induced cell apoptosis. However, the exact mechanism of apoptosis caused by Ni is still unclear. Understanding the mechanism of Ni-induced apoptosis may help in designing measures to prevent Ni toxicity.

H3K9 Trimethylation Silences Fas Expression To Confer Colon Carcinoma Immune Escape and 5-Fluorouracil Chemoresistance

The Fas-FasL effector mechanism plays a key role in cancer immune surveillance by host T cells, but metastatic human colon carcinoma often uses silencing Fas expression as a mechanism of immune evasion. The molecular mechanism under FAS transcriptional silencing in human colon carcinoma is unknown. We performed genome-wide chromatin immunoprecipitation sequencing analysis and identified that the FAS promoter is enriched with H3K9me3 in metastatic human colon carcinoma cells. The H3K9me3 level in the FAS promoter region is significantly higher in metastatic than in primary cancer cells, and it is inversely correlated with Fas expression level. We discovered that verticillin A is a selective inhibitor of histone methyltransferases SUV39H1, SUV39H2, and G9a/GLP that exhibit redundant functions in H3K9 trimethylation and FAS transcriptional silencing. Genome-wide gene expression analysis identified FAS as one of the verticillin A target genes. Verticillin A treatment decreased H3K9me3 levels in the FAS promoter and restored Fas expression. Furthermore, verticillin A exhibited greater efficacy than decitabine and vorinostat in overcoming colon carcinoma resistance to FasL-induced apoptosis. Verticillin A also increased DR5 expression and overcame colon carcinoma resistance to DR5 agonist drozitumab-induced apoptosis. Interestingly, verticillin A overcame metastatic colon carcinoma resistance to 5-fluorouracil in vitro and in vivo. Using an orthotopic colon cancer mouse model, we demonstrated that tumor-infiltrating cytotoxic T lymphocytes are FasL(+) and that FasL-mediated cancer immune surveillance is essential for colon carcinoma growth control in vivo. Our findings determine that H3K9me3 of the FAS promoter is a dominant mechanism underlying FAS silencing and resultant colon carcinoma immune evasion and progression.

Molecular aspects of bovine cystic ovarian disease pathogenesis

Cystic ovarian disease (COD) is one of the main causes of reproductive failure in cattle and causes severe economic loss to the dairy farm industry because it increases both days open in the post partum period and replacement rates due to infertility. This disease is the consequence of the failure of a mature follicle to ovulate at the time of ovulation in the estrous cycle. This review examines the evidence for the role of altered steroid and gonadotropin signaling systems and the proliferation/apoptosis balance in the ovary with cystic structures. This evidence suggests that changes in the expression of ovarian molecular components associated with these cellular mechanisms could play a fundamental role in the pathogenesis of COD. The evidence also shows that gonadotropin receptor expression in bovine cystic follicles is altered, which suggests that changes in the signaling system of gonadotropins could play a fundamental role in the pathogenesis of conditions characterized by altered ovulation, such as COD. Ovaries from animals with COD exhibit a disrupted steroid receptor pattern with modifications in the expression of coregulatory proteins. These changes in the pathways of endocrine action would trigger the changes in proliferation and apoptosis underlying the aberrant persistence of follicular cysts.

Free Spanish abstract: A Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/149/6/R251/suppl/DC1.

The story of CD4+ CD28- T cells revisited: solved or still ongoing?

CD4⁺CD28⁻ T cells are a unique type of proinflammatory T cells characterised by blockade of costimulatory CD28 receptor expression at the transcriptional level, which is still reversible by IL-12. In healthy individuals older than 65 years, these cells may accumulate to up to 50% of total CD4⁺ T lymphocytes as in many immune-mediated diseases, immunodeficiency, and specific infectious diseases. Here we focus on CD4⁺CD28⁻ T cells in chronic immune-mediated diseases, summarizing various phenotypic and functional characteristics, which vary depending on the underlying disease, disease activity, and concurrent treatment. CD4⁺CD28⁻ T cells present as effector/memory cells with increased replicative history and oligoclonality but reduced apoptosis. As an alternative costimulatory signal instead of CD28, not only natural killer cell receptors and Toll-like receptors, but also CD47, CTLA-4, OX40, and 4-1BB have to be considered. The proinflammatory and cytotoxic capacities of these cells indicate an involvement in progression and maintenance of chronic immune-mediated disease. So far it has been shown that treatment with TNF-α blockers, abatacept, statins, and polyclonal antilymphocyte globulins (ATG) mediates reduction of the CD4⁺CD28⁻ T cell level. The clinical relevance of targeting CD4⁺CD28⁻ T cells as a therapeutic option has not been examined so far.

The receptor for the complement C3a anaphylatoxin (C3aR) provides host protection against Listeria monocytogenes-induced apoptosis

Listeria monocytogenes is a Gram-positive intracellular bacterium that is acquired through tainted food and may lead to systemic infection and possible death. Despite the importance of the innate immune system in fighting L. monocytogenes infection, little is known about the role of complement and its activation products, including the potent C3a anaphylatoxin. In a model of systemic L. monocytogenes infection, we show that mice lacking the receptor for C3a (C3aR(-/-)) are significantly more sensitive to infection compared with wild-type mice, as demonstrated by decreased survival, increased bacterial burden, and increased damage to their livers and spleens. The inability of the C3aR(-/-) mice to clear the bacterial infection was not caused by defective macrophages or by a reduction in cytokines/chemokines known to be critical in the host response to L. monocytogenes, including IFN-γ and TNF-α. Instead, TUNEL staining, together with Fas, active caspase-3, and Bcl-2 expression data, indicates that the increased susceptibility of C3aR(-/-) mice to L. monocytogenes infection was largely caused by increased L. monocytogenes-induced apoptosis of myeloid and lymphoid cells in the spleen that are required for ultimate clearance of L. monocytogenes, including neutrophils, macrophages, dendritic cells, and T cells. These findings reveal an unexpected function of C3a/C3aR signaling during the host immune response that suppresses Fas expression and caspase-3 activity while increasing Bcl-2 expression, thereby providing protection to both myeloid and lymphoid cells against L. monocytogenes-induced apoptosis.

Sphingolipids: key regulators of apoptosis and pivotal players in cancer drug resistance

Drug resistance elicited by cancer cells still constitutes a huge problem that frequently impairs the efficacy of both conventional and novel molecular therapies. Chemotherapy usually acts to induce apoptosis in cancer cells; therefore, the investigation of apoptosis control and of the mechanisms used by cancer cells to evade apoptosis could be translated in an improvement of therapies. Among many tools acquired by cancer cells to this end, the de-regulated synthesis and metabolism of sphingolipids have been well documented. Sphingolipids are known to play many structural and signalling roles in cells, as they are involved in the control of growth, survival, adhesion, and motility. In particular, in order to increase survival, cancer cells: (a) counteract the accumulation of ceramide that is endowed with pro-apoptotic potential and is induced by many drugs; (b) increase the synthesis of sphingosine-1-phosphate and glucosylceramide that are pro-survivals signals; (c) modify the synthesis and the metabolism of complex glycosphingolipids, particularly increasing the levels of modified species of gangliosides such as 9-O acetylated GD3 (αNeu5Ac(2-8)αNeu5Ac(2-3)βGal(1-4)βGlc(1-1)Cer) or N-glycolyl GM3 (αNeu5Ac (2-3)βGal(1-4)βGlc(1-1)Cer) and de-N-acetyl GM3 (NeuNH(2)βGal(1-4)βGlc(1-1)Cer) endowed with anti-apoptotic roles and of globoside Gb3 related to a higher expression of the multidrug resistance gene MDR1. In light of this evidence, the employment of chemical or genetic approaches specifically targeting sphingolipid dysregulations appears a promising tool for the improvement of current chemotherapy efficacy.

Cytotoxic proteins and therapeutic targets in severe cutaneous adverse reactions

Severe cutaneous adverse reactions (SCARs), such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN), are rare but life-threatening conditions induced mainly by a variety of drugs. Until now, an effective treatment for SJS/TEN still remains unavailable. Current studies have suggested that the pathobiology of drug-mediated SJS and TEN involves major histocompatibility class (MHC) I-restricted activation of cytotoxic T lymphocytes (CTLs) response. This CTLs response requires several cytotoxic signals or mediators, including granulysin, perforin/granzyme B, and Fas/Fas ligand, to trigger extensive keratinocyte death. In this article, we will discuss the cytotoxic mechanisms of severe cutaneous adverse reactions and their potential applications on therapeutics for this disease.

Association between FAS A670G polymorphism and susceptibility to cervical cancer: evidence from a meta-analysis

Previous studies published to evaluate the association between FAS A670G polymorphism and susceptibility to cervical cancer provided conflicting findings. A meta-analysis of published case-control studies was performed to get a comprehensive evidence for the possible association. We searched in PubMed and Wanfang databases for eligible studies published before February 10, 2013. The odds ratio (OR) with 95% confidence interval (95% CI) was used to evaluate the association. Ten studies with a total of 4,904 participants were finally included into the meta-analysis. Overall, there was no obvious association between FAS A670G polymorphism and susceptibility to cervical cancer under all four genetic models (G versus A: OR = 0.97, 95% CI 0.84-1.11, P = 0.64; GG versus AA: OR = 0.92, 95% CI 0.69-1.24, P = 0.60; GG/AG versus AA: OR = 0.99, 95% CI 0.77-1.26, P = 0.92; GG versus AA/AG: OR = 0.92; 95% CI 0.68-1.25, P = 0.59). Subgroup analyses by ethnicity further showed that there was no association between FAS A670G polymorphism and susceptibility to cervical cancer in both Caucasians and Asians. There was no risk of publication bias. In summary, the meta-analysis suggests that there is no association between FAS A670G polymorphism and susceptibility to cervical cancer in both Caucasians and Asians.

Static mechanical stress induces apoptosis in rat endplate chondrocytes through MAPK and mitochondria-dependent caspase activation signaling pathways

Mechanical stress has detrimental effects on cartilaginous endplate chondrocytes due to apoptosis in vivo and in vitro. In this study, we investigated the possible apoptosis signaling pathways induced by mechanical stress in cultured rat cervical endplate chondrocytes. Static mechanical load significantly reduced cell viability in a time- and load-dependent manner, as demonstrated by the Cell Counting Kit-8 (CCK-8) assay. Chondrocyte apoptosis induced by mechanical stress was confirmed by annexin V/propidium iodide (PI) staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Western blot analysis revealed that static load-induced chondrocyte apoptosis was accompanied by increased phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (MAPK). The loss of mitochondrial membrane potential (ΔΨm), increased Cytochrome c release, and activated Caspase-9 and Caspase-3, indicating that the mitochondrial pathway is involved in mechanical stress-induced chondrocyte apoptosis. Treatment with inhibitors of JNK (SP600125), p38 MAPK (SB203580), and ERK (PD98059) prior to mechanical stimulation reversed both the static load-induced chondrocyte apoptosis and the activation of JNK, p38 MAPK, and ERK. Taken together, the data presented in this study demonstrate that mechanical stress induces apoptosis in rat cervical endplate chondrocytes through the MAPK-mediated mitochondrial apoptotic pathway.

Phosphanegold(I) dithiocarbamates, R3PAu[SC(=S)N((i)Pr)CH2CH2OH] for R = Ph, Cy and Et: role of phosphane-bound R substituents upon in vitro cytotoxicity against MCF-7R breast cancer cells and cell death pathways

The synthesis and characterisation of R3PAu[S2CN((i)Pr)CH2CH2OH], for R = Ph (1), Cy (2) and Et (3)4, is reported. Compounds 1-3 are cytotoxic against the doxorubicin-resistant breast cancer cell line, MCF-7R, with 1 exhibiting greater potency and cytotoxicity than either of doxorubicin and cisplatin. Based on human apoptosis PCR-array analysis, caspase activities, DNA fragmentation, cell apoptotic assays, intracellular reactive oxygen species (ROS) measurements and human topoisomerase I inhibition, induction of apoptosis by 1, and necrosis by 2 and 3, are demonstrated, by both extrinsic and intrinsic pathways. Compound 1 activates the p53 gene, 2 activates only the p73 gene, whereas 3 activates both the p53 and p73 genes. Compounds 1 and 3 activate NF-κB, and each inhibits topoisomerase I.

Distinct roles of Kaposi's sarcoma-associated herpesvirus-encoded viral interferon regulatory factors in inflammatory response and cancer

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). Similar to other herpesviruses, KSHV has two life cycles, latency and lytic replication. In latency, the KSHV genome persists as a circular episome in the nucleus of the host cell and only a few viral genes are expressed. In this review, we focus on oncogenic, antiapoptotic, and immunomodulating properties of KSHV-encoded homologues of cellular interferon regulatory factors (IRFs)--viral IRF1 (vIRF1) to vIRF4--and their possible role in the KSHV-mediated antiviral response, apoptosis, and oncogenicity.

The influence of p53 functions on radiation-induced inflammatory bystander-type signaling in murine bone marrow

Radiation-induced bystander and abscopal effects, in which DNA damage is produced by inter-cellular communication, indicate mechanisms of generating damage in addition to those observed in directly irradiated cells. In this article, we show that the bone marrow of irradiated p53(+/+) mice, but not p53(-/-) mice, produces the inflammatory pro-apoptotic cytokines FasL and TNF-α able to induce p53-independent apoptosis in vitro in nonirradiated p53(-/-) bone marrow cells. Using a congenic sex-mismatch bone marrow transplantation protocol to generate chimeric mice, p53(-/-) hemopoietic cells functioning in a p53(+/+) bone marrow stromal microenvironment exhibited greater cell killing after irradiation than p53(-/-) hemopoietic cells in a p53(-/-) microenvironment. Cytogenetic analysis demonstrated fewer damaged p53(-/-) cells in a p53(+/+) microenvironment than p53(-/-) cells in a p53(-/-) microenvironment. Using the two different model systems, the findings implicate inflammatory tissue processes induced as a consequence of p53-dependent cellular responses to the initial radiation damage, producing cytokines that subsequently induce ongoing p53-independent apoptosis. As inactivation of the p53 tumor suppressor pathway is a common event in malignant cells developing in a stromal microenvironment that has normal p53 function, the signaling processes identified in the current investigations have potential implications for disease pathogenesis and therapy.

The influence of R substituents in triphenylphosphinegold(I) carbonimidothioates, Ph3PAu[SC(OR)=NPh] (R=Me, Et and iPr), upon in vitro cytotoxicity against the HT-29 colon cancer cell line and upon apoptotic pathways

The Ph3PAu[SC(OR)=NPh], R=Me (1), Et (2) and iPr (3), compounds are significantly cytotoxic to the HT-29 cancer cell line with 1 being the most active. Based on human apoptosis PCR-array analysis, caspase activities, DNA fragmentation, cell apoptotic assays, intracellular reactive oxygen species (ROS) measurements and human topoisomerase I inhibition, induction of apoptosis is demonstrated and both the extrinsic and intrinsic pathways of apoptosis have been shown to occur. Compound 1 activates the p73 gene, whereas each of 2 and 3 activates the p53 gene. An additional apoptotic mechanism is exhibited by 2, that is, via the JNK/MAP pathway.

Association between FAS-1377 G/A polymorphism and susceptibility to gastric cancer: evidence from a meta-analysis

Previous studies published to evaluate the association between FAS-1377 G/A polymorphism and susceptibility to gastric cancer provided inconclusive outcomes. To derive a more precise estimation on this association, a meta-analysis of published case-control studies was performed. Eligible studies up to November 13, 2012 were identified from PubMed, Wanfang Medicine database, and Web of Science. Nine studies with a total of 2,086 cases and 2,701 controls were finally included into this meta-analysis. Overall, there was an obvious association between FAS-1377 G/A polymorphism and susceptibility to gastric cancer (for AA versus GG: odds ratio (OR) = 1.38; 95 % confidence interval (CI) 1.00-1.91, P = 0.05; for AA versus

GA/GG

OR = 1.28; 95 %CI 1.07-1.53, P = 0.006). After excluding studies with low quality, there was no between-study heterogeneity, and there was still an obvious association between FAS-1377 G/A polymorphism and susceptibility to gastric cancer (for AA versus GG: OR = 1.25; 95 %CI 1.02-1.52, P = 0.03; for AA versus

GA/GG

OR = 1.27; 95 %CI 1.05-1.53, P = 0.01). Subgroup analyses by ethnicity showed that the association above was still obvious in Asians, but the association was still unclear in Caucasians owing to the limited sample. In summary, this meta-analysis suggests that the FAS-1377 G/A polymorphism is associated with susceptibility to gastric cancer, especially in Asians. More studies from Caucasians are needed to provide further evidence for the possible association in Caucasians.

Role of TNF-associated cytokines in renal tubular cell apoptosis induced by hyperoxaluria

Crystal-cell interaction has been reported as one of the most crucial steps in urinary stone formation. Hyperoxaluria-induced apoptotic changes in renal tubular epithelial cells is the end-stage of this interaction. We aimed to evaluate the possible pathways responsible in the induction of apoptosis within the involved cells by assessing the receptoral expression of three different pathways. 16 male Spraque-Dowley rats were divided into two groups: Group 1 (n:8) received only distilled water; Group 2 (n:8) received 0.75 % ethylene glycol (EG) in their daily water to induce hyperoxaluria for 2 weeks. After 24 h urine collection, all animals were euthenized and right kidneys were removed and fixed for immunohistochemical evaluation. Oxalate and creatinine levels (in 24 h-urine) and FAS, tumor necrosis factor (TNF), TNF-related apoptosis-inducing ligand (TRAIL) and TRAIL receptor-2 expressions (in tissue) have been assessed. In addition to TNF (p = 0.0007) expression; both FAS (p = 0.0129 ) and FASL (p = 0.032) expressions significantly increased in animals treated with EG. The expressions of TRAIL (p = 0.49) and TRAIL-R2 (p = 0.34) receptors did not change statistically after hyperoxaluria induction. Although a positive correlation with cytokine expression density and 24 h-urinary oxalate expression (mg oxalate/mg creatinine) has been assessed with TNF (p = 0.04, r = 0.82), FAS (p = 0.05, r = 0.80), FAS-L (p = 0.04, r = 0.82); no correlation could be demonstrated between TRAIL and TRAIL R2 expressions. Our results indicate that apoptosis induced by oxalate is possibly mediated via TNF and FAS pathways. However, TRAIL and TRAIL-R2 seemed to have no function in the cascade. Correlation with urinary oxalate levels did further strengthen the findings.

Thiazolidinediones protect mouse pancreatic β-cells directly from cytokine-induced cytotoxicity through PPARγ-dependent mechanisms

Since most of the current studies of thiazolidinediones (TZDs) are only focused on improving glycemic control, increasing insulin sensitivity, and regulating inflammatory states in Type 2 Diabetes, it is still controversial whether TZDs have direct, protective effects on pancreatic β-cells in autoimmune diabetes. Here, we show the protective effects of TZDs on mouse pancreatic β-cell line cells (NIT-1) impaired by exposure to inflammatory cytokines (IL-1β and IFN-γ) and explore the potential mechanisms for this. The apoptosis rate and caspase-3 activity were remarkably increased, and insulin secretion response to glucose was impaired severely by exposure to IL-1β/IFN-γ for 48 h compared to control cells, whereas apoptosis rate and caspase-3 activity were significantly decreased in cells with treatment of rosiglitazone (RGZ) or pioglitazone (PIG), and the capacity for insulin secretion response to glucose was recovered. TZDs protect pancreatic β-cells from cytokine-induced cytotoxicity through PPARγ activation. The protective effects of the TZDs on NIT-1 cells disappeared when PPARγ was blocked with PPARγ-siRNA interference or treatment with GW9662, the PPARγ antagonist. Additionally, the enhancement of PPARγ expression by treatment with TZDs inhibited the expression of caspase 3 in IL-1β/IFN-γ-induced NIT-cells. Also, the inhibition of caspase 3 expression by TZDs was blocked by co-treatment with GW9662 or infection with PPARγ-siRNA. Taken together, our data suggest that TZDs might serve to protect pancreatic β-cells directly from cytokine-induced cytotoxicity through a PPARγ-dependent pathway, and caspase-3 may play an important role in the mechanisms involved.