Expression of apoptotic nuclei by ultrastructural terminal deoxyribonucleotidyl transferase mediated dUTP nick end labeling and detection of FasL, caspases and PARP protein molecules in cadmium induced acute alveolar cell injury

The Antioxidant Activity of Betanin protects MRC-5 cells Against Cadmium Induced Toxicity

Cadmium (Cd) can induce both acute and chronic effects in the lungs depending on the time and the exposure route. Betanin is a component derived from the roots of red beets and it is well-known for its antioxidant and anti-apoptosis effects. The current study aimed to survey the protective effects of betanin on cell toxicity induced by Cd. Different concentration of Cd alone and in combination with betanin was assessed in MRC-5 cells. The viability and oxidative stress were measured using resazurin and DCF-DA methods respectively. Apoptotic cells were assessed by PI staining of the fragmented DNA and western blot analysis detected the activation of caspase 3 and PARP proteins. Cd exposure for 24 h declined viability and increased ROS production in MRC-5 cells compared to the control group (p < 0.001). Also, Cd (35 μM) elevated DNA fragmentation (p < 0.05), and the level of caspase 3-cleaved and cleaved PARP proteins in MRC-5 cells (p < 0.001). Co-treatment of cells with betanin for 24 h significantly enhanced viability in concentrations of 1.25 and 2.5 μM (p < 0.001) and 5 μM (p < 0.05) and declined ROS generation (1.25 and 5 μM p < 0.001, and 2.5 μM p < 0.01). As well as, betanin reduced DNA fragmentation (p < 0.01), and the markers of apoptosis (p < 0.001) compared to the Cd-treated group. In conclusion, betanin protects lung cells against Cd-induced toxicity through antioxidant activity and inhibition of apoptosis.

Synergistic antitumor effect of polysaccharide from Lachnum sp. in combination with cyclophosphamide in hepatocellular carcinoma

Combination therapy with chemotherapeutics is attracting increasing attention as an important treatment option for hepatocellular carcinoma (HCC) due to its complex pathological characteristics. In this study, as a new therapy strategy, combination treatment of LEP-2a (a non-toxic polysaccharide from Lachnum sp.) with cyclophosphamide (CTX) was investigated. Results showed that combination treatment with LEP-2a and CTX processed a significantly synergistic anti-tumor effect in H22 tumor-bearing mice through Fas/FasL mediated caspase-dependent death pathway and mitochondria apoptosis pathway. Moreover, our study indicated that LEP-2a played a crucial role in enhancement of immune response, inhibition of tumor angiogenesis and down-regulation of survival associated proteins. Notably, side effects induced by CTX were relieved after LEP-2a treatment. These results support the conception that LEP-2a has the potential as an ideal adjuvant agent for a more effective combination therapy with CTX against HCC.

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.

In vitro toxicity evaluation of engineered cadmium-coated silica nanoparticles on human pulmonary cells

Cytotoxicity of cadmium-containing silica nanoparticles Cd-SiO2NPs (0.05-100 µg/mL) versus SiO2NPs and CdCl2 was evaluated by an in vitro test battery in A549 by assessing (i) mitochondrial function, (ii) membrane integrity/cell morphology, (iii) cell growth/proliferation, (iv) apoptotic pathway, (v) oxidative stress, after short- (24-48 h) and long-term (10 days) exposure. Both Cd-SiO2NPs and CdCl2 produced dose-dependent cytotoxic effects: (i) MTT-assay: similar cytotoxicity pattern was observed at both 24 and 48 h, with a more Cd-SiO2NPs pronounced effect than CdCl2. Cd-SiO2NPs induced mortality (about 50%) at 1  μ g/mL, CdCl2 at 25  μ g/mL; (ii) calcein-AM/PI staining: decrease in cell viability, noticeable at 25  μ g/mL, enhanced markedly at 50 and 100  μ g/mL, after 24 h. Cd-SiO2NPs induced higher mortality than CdCl2 (25% versus 4%, resp., at 25  μ g/mL) with further exacerbation after 48h; (iii) clonogenic assay: exposure for longer period (10 days) compromised the A549 proliferative capacity at very low dose (0.05  μ g/mL); (iv) a progressive activation of caspase-3 immunolabelling was detected already at 1  μ g/mL; (v) GSH intracellular level was modified by all compounds. In summary, in vitro data demonstrated that both Cd-SiO2NPs and CdCl2 affected all investigated endpoints, more markedly after Cd-SiO2NPs, while SiO2NPs influenced GSH only.

Over-expression of human endosulfatase-1 exacerbates cadmium-induced injury to transformed human lung cells in vitro

Environmental exposure to cadmium is known to cause damage to alveolar epithelial cells of the lung, impair their capacity to repair, and result in permanent structural alterations. Cell surface heparan sulfate proteoglycans (HSPGs) can modulate cell responses to injury through their interactions with soluble effector molecules. These interactions are often sulfate specific, and the removal of sulfate groups from HS side chains could be expected to influence cellular injury, such as that caused by exposure to cadmium. The goal of this study was to define the role 6-O-sulfate plays in cellular responses to cadmium exposure in two pulmonary epithelial cancer cell lines (H292 and A549) and in normal human primary alveolar type II (hAT2) cells. Sulfate levels were modified by transduced transient over-expression of 6-O-endosulfatase (HSulf-1), a membrane-bound enzyme which specifically removes 6-O-sulfate groups from HSPG side chains. Results showed that cadmium decreased cell viability and activated apoptosis pathways at low concentrations in hAT2 cells but not in the cancer cells. HSulf-1 over-expression, on the contrary, decreased cell viability and activated apoptosis pathways in H292 and A549 cells but not in hAT2 cells. When combined with cadmium, HSulf-1 over-expression further decreased cell viability and exacerbated the activation of apoptosis pathways in the transformed cells but did not add to the toxicity in hAT2 cells. The finding that HSulf-1 sensitizes these cancer cells and intensifies the injury induced by cadmium suggests that 6-O-sulfate groups on HSPGs may play important roles in protection against certain environmental toxicants, such as heavy metals.

Role of Bcl-2 in tumour cell survival and implications for pharmacotherapy

OBJECTIVES

Bcl-2 is a protein that inhibits apoptosis, leading to cell survival. The Bcl-2 family has six different anti-apoptotic proteins, three pro-apoptotic proteins that are similar in structure, and other integrating proteins that function as promotors or inhibitors in the progression of apoptosis. In this discussion paper, we provide an overview of apoptosis, the role of Bcl-2 in normal cellular and molecular processes, and the role of Bcl-2 in tumour cell survival. It focuses primarily on anti-apoptotic Bcl-2, its activation in cancer, the manner in which it regulates the intrinsic and extrinsic mechanisms of apoptosis, and its broad molecular interactions with other critical proteins in the cell. Certain cancer treatments are reviewed and related directions for the future are presented.

KEY FINDINGS

Apoptosis is common to all organisms - for eukaryotes it is a normal process of development and regeneration. The rate at which apoptosis occurs is critical to the survival of the organism, as too much can lead to the onset of degenerative diseases such as dementia, and too little may lead to cancer. FKBP-38 is a binding protein that has been discovered to be upregulated in highly aggressive cancers and binds to Bcl-2 rather than the pro-apoptotics to induce a state of hyper-mitosis. A short binding protein (Nur-77) provides new insights into Bcl-2 'masking'. Nurr-77 binds to Bcl-2 and exposes the BH3 domain, transforming it from a cancer promoter to an unorthodox cancer inhibitor. This presents in itself an interesting and exciting opportunity - increasing the rate of apoptosis in neoplastic cells that are usually protected by Bcl-2 activity at the mitochondria.

SUMMARY

Development of drugs in the form of BH3-only and BH123 mimetic drugs provide a interesting avenue for cancer therapy for the future. Drugs that can either promote, or mimic anti-IAP activity such as Smac/Diablo would certainly be productive, thereby inducing apoptosis. Medicinal usage which can effectively suppress FKBP38 in Bcl-2-dependent cancers would provide further arsenal to combat apoptotic irregularities, particularly a treatment that is more dominant than kinetin riboside. WAVE-1 inhibitors may effectively suppress the phosphorylation of Bcl-2, thereby potentially reducing hyper-mitosis and increasing apoptosis. Recent findings shed molecular light on PDT, namely ER stress, and potential for anti-cancer therapy via either apoptosis or autophagy. A drug that can effectively upregulate Nurr-77, thereby masking the anti-apoptotic properties of Bcl-2, would indeed be life-saving for cancer patients.

Differential role of the Fas/Fas ligand apoptotic pathway in inflammation and lung fibrosis associated with reovirus 1/L-induced bronchiolitis obliterans organizing pneumonia and acute respiratory distress syndrome

Bronchiolitis obliterans organizing pneumonia (BOOP) and acute respiratory distress syndrome (ARDS) are two clinically and histologically distinct syndromes sharing the presence of an inflammatory and fibrotic component. Apoptosis via the Fas/Fas ligand (FasL) pathway plays an important role in the development of acute lung injury and fibrosis characteristic of these and other pulmonary inflammatory and fibrotic syndromes. We evaluated the role of apoptosis via the Fas/FasL pathway in the development of pulmonary inflammation and fibrosis in reovirus 1/L-induced BOOP and ARDS. CBA/J mice were intranasally inoculated with saline, 1 x 10(6) (BOOP), or 1 x 10(7) (ARDS) PFU reovirus 1/L, and evaluated at various days postinoculation for in situ apoptosis by TUNEL analysis and Fas/FasL expression. Our results demonstrate the presence of apoptotic cells and up-regulation of Fas/FasL expression in alveolar epithelium and in infiltrating cells during the inflammatory and fibrotic stages of both reovirus 1/L-induced ARDS and BOOP. Treatment of mice with the caspase 8 inhibitor, zIETD-fmk, inhibited apoptosis, inflammation, and fibrotic lesion development in reovirus 1/L-induced BOOP and ARDS. However, CBA/KlJms-Fas(lpr-cg)/J mice, which carry a point mutation in the Fas cytoplasmic region that abolishes the ability of Fas to transduce an apoptotic signal, do not develop pulmonary inflammation and fibrotic lesions associated with reovirus 1/L-induced BOOP, but still develop inflammation and fibrotic lesions associated with reovirus 1/L-induced ARDS. These results suggest a differential role for the Fas/FasL apoptotic pathway in the development of inflammation and fibrotic lesions associated with BOOP and ARDS.

The role of phosphodiesterase 3 in endotoxin-induced acute kidney injury

Background

Acute kidney injury frequently accompanies sepsis. Endotoxin is known to reduce tissue levels of cAMP and low levels of cAMP have been associated with renal injury. We, therefore, hypothesized that endotoxin induced renal injury by activating phosphodiesterase 3 (PDE3) which metabolizes cAMP and that amrinone an inhibitor of PDE3 would prevent the renal injury.

Methods

Animals were divided into three groups (n = 7/group): 1) Control (0.9% NaCl infusion without LPS); 2) LPS (0.9% NaCl infusion with LPS); 3) Amrinone+LPS (Amrinone infusion with LPS). Either lipopolysaccharide (LPS) or vehicle was injected via the jugular vein and the rats followed for 3 hours. We explored the expression of PDE3 isoenzymes and the concentrations of cAMP in the tissue.

Results

The PDE3B gene but not PDE3A was upregulated in the kidney of LPS group. Immunohistochemistry also showed that PDE3B was expressed in the distal tubule in the controls and LPS caused PDE3B expression in the proximal as well. However, PDE3A was not expressed in the kidney either in the control or LPS treated groups. Tissue level of cAMP was decreased after LPS and was associated with an increase in blood urea nitrogen, creatinine, ultrastructural proximal tubular changes, and expression of inducible nitric oxide synthase (iNOS) in the endotoxemic kidney. In septic animals the phosphodiesterase 3 inhibitor, amrinone, preserved the tissue cAMP level, renal structural changes, and attenuated the increased blood urea nitrogen, creatinine, and iNOS expression in the kidney.

Conclusion

These findings suggest a significant role for PDE3B as an important mediator of LPS-induced acute kidney injury.

Loss of cyclin g1 expression in human uterine leiomyoma cells induces apoptosis

Observations from the authors' laboratory suggest a physiological role for increased cyclin G1 protein levels in human uterine leiomyoma. The hypothesis of the present study is that the strategic modulation of cyclin G1 by antisense technology will inhibit the survival of in vitro-grown uterine leiomyoma cells. Cultured uterine leiomyoma cells were transfected with cyclin G1 ribbon-type antisense oligonucleotide (cyclin G1 RiAS) to effectively reduce cyclin G1 expression. Cell viability, in situ terminal deoxyuridine nick end-labeling (TUNEL) assay, flow cytometry, DNA fragmentation, and expression of cell cycle regulatory-related proteins were evaluated by Western blot. Antisense oligonucleotides compromised uterine leiomyoma cell viability and inducted apoptosis in a caspase-independent mechanism. In situ TUNEL and DNA fragmentation revealed apoptosis induction, and fluorescent-activated cell sorting analysis showed increased sub-G1-phase cells. Furthermore, abrogation of cyclin G1 enhanced p53 accumulation, phosphorylation of p53 at Ser-15 residue, and increased expression of cyclin-dependent kinase inhibitors p21 and p27. These data imply that cyclin G1 expression is associated with growth promotion and the potential utility and novelty of using ribbon-type antisense oligonucleotides as a gene therapy strategy to treat human uterine leiomyoma.

Effects of subchronic digestive exposure to organic or inorganic cadmium on biomarkers in rat tissues

In an experimental food chain, Wistar rats were fed cadmium (Cd) in an inorganic (CdCl(2)) or organic (mainly associated with metallothionein from Helix aspersa snail viscera) form. After 1 month of exposure to 100 microg inorganic Cd g(-1) in food, an induction of metallothionein was observed in all target tissues. In liver, glutathione peroxidase (GSH-Px) activity decreased and alanine aminotransferase (ALAT) activity increased, suggesting that Cd causes hepatotoxicity. However, lipid peroxidation as well as catalase and caspase 3 (a marker of apoptosis) activities were not modified. At a rather low exposure (2.5 microg Cd g(-1)), metallothionein level in the kidney was found to be the most sensitive biomarker of exposure for both Cd forms. In the small intestine of rats ingesting inorganic Cd, metallothionein expression was significantly higher than that observed for rats fed organic Cd. Present results allowed proposing a simple design to assess the effect of a chemical in a trophic transfer approach.