Methods utilized in the study of apoptosis

Selenious-β-lactoglobulin induces the apoptosis of human lung cancer A549 cells via an intrinsic mitochondrial pathway

In this study, the cytotoxic activity of selenious-β-lactoglobulin (Se-β-Lg) and the anticancer mechanism were investigated in human lung cancer A549 cells in vitro. MTT assay showed that Se-β-Lg at 200 μg/mL exhibited a significant suppression effect on A549 cells and the maximum inhibition rate reached 90% after 72 h treatment. Flow cytometry analysis revealed that 200 μg/mL of Se-β-Lg induced cell cycle arrest at G0/G1 phase. Cell apoptosis was induced via the generation of reactive oxygen species (ROS) and the decrease of mitochondrial membrane potential (ΔΨm) in a time-dependent manner. Furthermore, Se-β-Lg suppressed the expression of Bcl-2 and improved the level of Bax, leading to the release of cytochrome c and a higher expression of caspase-3 in A549 cells. In summary, Se-β-Lg could induce apoptosis in A549 cells via an intrinsic mitochondrial pathway and it might serve as a potential therapeutic agent for human lung cancer.

In situ cultured preantral follicles is a useful model to evaluate the effect of anticancer drugs on caprine folliculogenesis

Despite the increase in the incidence of cancer, the number of women who survive cancer treatment is growing. However, one of the principal results of chemotherapy is premature ovarian failure (POF). The aim of this study was to use the in situ culture preantral follicles as an in vitro model to evaluate the toxicity of two anticancer drugs, doxorubicin (DXR) and paclitaxel (PTX), on the integrity and development of ovarian follicles. Fragments of the ovarian cortex of goats were cultured in vitro for 1 or 7 days in α-MEM(+) supplemented with different concentrations of DXR (0.003, 0.03, or 0.3 µg/mL) and PTX (0.001, 0.01, or 0.1 µg/mL). Analyses were performed before and after culture to evaluate tissue integrity by classical histology, apoptosis by TUNEL assay, DNA laddering kit and the detection of activated caspase 3, and DNA damage by the immune detection of phosphorylated histone H2A.x (H2AXph139). Both DXR and PTX reduced the number of morphologically normal primordial and developing follicles. Positive staining for TUNEL and active caspase 3 was detected in all the samples (P < 0.05). Therefore, we propose the in situ culture of caprine preantral follicles as a useful experimental model for assessing the toxic effects of the chemotherapeutic agents on ovarian folliculogenesis. Microsc. Res. Tech. 79:773-781, 2016. © 2016 Wiley Periodicals, Inc.

Simvastatin enhances human osteoblast proliferation involved in mitochondrial energy generation

Simvastatin has been shown to stimulate osteogenic cell differentiation. Our previous study showed osteoblasts on trabecular surface are increased by simvastatin treatment in animal study. However, whether simvastatin stimulates osteoblast proliferation and by what molecular mechanism have not been adequately investigated. Because the mitochondrial function is crucial for cell survival and proliferation, we hypothesize that simvastatin may promote human osteoblast (hOBs) proliferation and it may be related to mitochondrial function. Our results showed that simvastatin significantly enhanced proliferation and increased both mRNA and protein levels of cyclin D2, Bcl-2 and the ratio of Bcl-2 to Bax (Bcl-2/Bax). Furthermore, simvastatin increased mitochondrial activity and ATP content of hOBs. Most importantly, treatment with ATP synthase blocker, oligomycin, significantly decreased both simvastatin-stimulated ATP content and cell proliferation, and completely reversed the simvastatin-induced up-regulation of cyclin D2 and Bcl-2 expression in hOBs. On the other hand, rotenone, the complex I blocker, also partially blocked simvastatin-stimulated ATP content and cell proliferation, but the blocker did not suppress the effect of simvastatin on cyclin D2 and Bcl-2 expression. These results indicate that the up-regulation of cyclin D2 and Bcl-2/Bax by simvastatin depends on the intact function of ATP synthase in the mitochondria of hOBs. It suggests that simvastatin may promote hOB proliferation, at least partly, via up-regulating mitochondrial function and subsequently cyclin D2 and Bcl-2/Bax expression. The findings provide new information for the basic medical science in bone physiology and for new therapy strategy of simvastatin on bone formation in future.

Electromagnetic fields enhance chondrogenesis of human adipose-derived stem cells in a chondrogenic microenvironment in vitro

We tested the hypothesis that electromagnetic field (EMF) stimulation enhances chondrogenesis in human adipose-derived stem cells (ADSCs) in a chondrogenic microenvironment. A two-dimensional hyaluronan (HA)-coated well (2D-HA) and a three-dimensional pellet culture system (3D-pellet) were used as chondrogenic microenvironments. The ADSCs were cultured in 2D-HA or 3D-pellet, and then treated with clinical-use pulse electromagnetic field (PEMF) or the innovative single-pulse electromagnetic field (SPEMF) stimulation. The cytotoxicity, cell viability, and chondrogenic and osteogenic differentiations were analyzed after PEMF or SPEMF treatment. The modules of PEMF and SPEMF stimulations used in this study did not cause cytotoxicity or alter cell viability in ADSCs. Both PEMF and SPEMF enhanced the chondrogenic gene expression (SOX-9, collagen type II, and aggrecan) of ADSCs cultured in 2D-HA and 3D-pellet. The expressions of bone matrix genes (osteocalcin and collagen type I) of ADSCs were not changed after SPEMF treatment in 2D-HA and 3D-pellet; however, they were enhanced by PEMF treatment. Both PEMF and SPEMF increased the cartilaginous matrix (sulfated glycosaminoglycan) deposition of ADSCs. However, PEMF treatment also increased mineralization of ADSCs, but SPEMF treatment did not. Both PEMF and SPEMF enhanced chondrogenic differentiation of ADSCs cultured in a chondrogenic microenvironment. SPEMF treatment enhanced ADSC chondrogenesis, but not osteogenesis, when the cells were cultured in a chondrogenic microenvironment. However, PEMF enhanced both osteogenesis and chondrogenesis under the same conditions. Thus the combination of a chondrogenic microenvironment with SPEMF stimulation can promote chondrogenic differentiation of ADSCs and may be applicable to articular cartilage tissue engineering.

NONSTEROIDAL ANTI-INFLAMMATORY DRUGS ARREST CELL CYCLE IN G0/G1PHASE AND INDUCE CELL DEATH IN OSTEOBLAST-ENRICHED CULTURES

Nonsteroidal anti-inflammatory drugs have been widely prescribed for orthopaedic patients to relieve pain and chronic inflammation. However, it has been demonstrated that NSAIDs suppress bone repair and remodeling in vivo. We have reported that ketorolac inhibits bone repair in vivo and its critical effective timing is at the early stage of endochondral ossification. Our previous results showed that ketorolac and indomethacin inhibit osteoblast proliferation in vitro, suggesting that this effect may be one of the mechanisms contributing to the suppressive effect of NSAIDs on bone remodeling. Cell proliferation and death of osteoblasts should be well regulated through some relative apoptotic and mitotic factors during normal bone remodeling process. Accordingly, we proposed that the induction of osteoblastic cell death of NSAIDs might be one of the mechanisms involving their suppressive effect on bone remodeling in vivo. In this study, we investigated whether NSAIDs arrest osteoblastic cell cycle and/or induce cell death. Whether the mechanism was mediated through prostaglandin (PG) pathway. We tested the effects of ketorolac, indomethacin, diclofenac, piroxicam on cell cycle kinetics, cytotoxicity, and cell death pattern in osteoblast-enriched cultures derived from fetal rat calvaria. Our results showed that ketorolac and indomethacin arrested cell cycle at G0/G1phase. All the 4 NSAIDs had cytotoxic effects and these effects were concentration dependent. The sequence of the cytotoxic effects of these four NSAIDs at 10-4M were indomethacin > diclofenac > ketorolac > piroxicam. Both PGE1and PGE2(10-10-10-8M) also significantly elevated the LDH leakage of osteoblasts, while PGF2αhad no significant effect. These results revealed that the cytotoxic effects of NSAIDs on osteoblasts might not be through inhibiting prostaglandin synthesis. They may be through PG-independent pathways. The results from flow cytometry followed by AnnexinV-FITC and propidium iodide double staining showed that 24 hours treatment of all the 4 NSAIDs (10-6and 10-4M) significantly induced both apoptosis (p<0.01) and necrosis (p<0.01, or p<0.05) in osteoblast cultures. These effects of NSAIDs on cell cycle arrest and cell death induction in osteoblasts may be one of the important mechanisms contributing to their suppressive effect on bone repair and bone remodeling in vivo.

Apoptose na maturação placentária de vacas em diferentes estágios de gestação: evidenciação imuno-histoquímica e bioquímica

Apoptose tem um papel importante na manutenção da homeostase placentária, e o desequilíbrio desse processo pode comprometer a gestação. O objetivo do presente estudo foi avaliar a ocorrencia de apoptose em amostras de placenta de vacas em diferentes fases de gestação. Amostras de placentomos de 15 vacas saudáveis com 4 (n=5), 6 (n=5) e 9 (n=5) meses de gestação foram colhidas e processadas rotineiramente para a histologia, imuno-histoquímica e isolamento de DNA. As lâminas obtidas foram coradas em HE, ou submetidas à análise imuno-histoquímica das proteínas pró-apoptóticas caspase-3 e Bax, e da proteína anti-apoptótica Bcl-2. O DNA isolado foi submetido à eletroforese em gel de agarose para detecção da fragmentação internucleossômica do genoma. Os resultados de histomorfometria revelaram que as células apoptóticas aumentaram progressivamente com o avanço da gestação. Confirmou-se a apoptose pela fragmentação característica do DNA genômico, visualizada pelo clássico "padrão em escada" na eletroforese em gel de agarose. Adcionalmente, a imunoexpressão de caspase-3, Bax e Bcl-2 foram observadas em todas as amostras. Entretanto, a proteína caspase-3 apresentou marcação mais intensa em todos os tempos gestacionais, quando comparada com a marcação das proteínas Bcl-2 e Bax. Esses resultados confirmam e reforçam a importância da apoptose na maturação placentária. Além disto, indica que caspase-3, Bax e Bcl-2 estão envolvidas nos mecanismos de ativação da apoptose pela via intrínseca mitocondrial ao longo da gestação, contribuindo para o equilíbrio fisiológico da celularidade e renovação celular na placenta bovina.

Selenocystine induces reactive oxygen species-mediated apoptosis in human cancer cells

Epidemiological and clinical studies have demonstrated that dietary supplementation of selenium (Se) could reduce the incidence of human cancers. In this study, selenocystine, a nutritionally available selenoamino acid, was identified as a novel agent with broad-spectrum antitumor activity. A panel of eight human cancer cell lines was shown to be susceptible to selenocystine, with IC(50) values ranging from 3.6 to 37.0 microM. Selenocystine induced dose-dependent apoptosis in A375, HepG2 and MCF7 cells was evaluated by flow cytometric analysis and annexin-V staining assay. Mechanistic studies showed time- and dose-dependent increases in intracellular reactive oxygen species (ROS) in susceptible cancer cells (MCF7 and HepG2 cells) treated with selenocystine. However, selenocystine-induced ROS overproduction was not observed in non-susceptible normal human fibroblast Hs68 cells. Significant DNA strand breaks were observed in selenocystine-treated MCF7 and HepG2 cells as examined by single-cell gel electrophoresis (Comet assay). The thiol-reducing antioxidants, glutathione and N-acetylcysteine, inhibited intracellular ROS generation, DNA strand breaks and accumulation of sub-G1 population in MCF7 cells exposed to selenocystine. Our results suggest a possible role of ROS as a mediator of the signaling pathway of selenocystine-induced, DNA damage-mediated apoptosis in susceptible cancer cells.

Mitochondria-mediated apoptosis in human breast carcinoma MCF-7 cells induced by a novel selenadiazole derivative

The role of organoselenium compounds as potent cancer chemopreventive and chemotherapeutic agents has been supported by epidemiological, preclinical and clinical studies. In this study, a novel selenadiazole derivative, 1,2,5-selenadiazolo-[3,4-d]pyrimidine-5,7-(4H,6H)-dione (SPO), is identified as a potent antiproliferative agent against human breast adrenocarcinoma MCF-7 cells, human hepatoma HepG2 cells and human melanoma A375 cells. Induction of apoptosis in MCF-7 and A375 cells by SPO was evidenced by accumulation of sub-G1 cell population, DNA fragmentation and nuclear condensation. Further investigation on intracellular mechanisms found that SPO treatments induced activation of caspase-8 and caspase-9, overproduction of reactive oxygen species, and depletion of mitochondrial membrane potential (Delta Psi m) through regulating the expression of pro-survival and pro-apoptotic Bcl-2 family members. Our findings suggest that SPO is a promising novel organoselenium compound with potential in the treatment of human cancers.

Effects of anti-inflammatory drugs on proliferation, cytotoxicity and osteogenesis in bone marrow mesenchymal stem cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) were found to suppress proliferation and induce cell death in cultured osteoblasts, and steroids were found to decrease the osteogenesis potential of mesenchymal stem cells. In this study, we further tested the effects of anti-inflammatory drugs (AIDs) on the functions of bone marrow mesenchymal stem cells (BMSCs). The BMSCs from mice (D1-cells) and humans (hBMSCs) were treated with dexamethasone (10(-7) to 10(-6) M), cyclooxygenase-2 (COX-2) selective NSAIDs (10(-6) to 10(-5) M) and non-selective NSAIDs (10(-5) to 10(-4) M). Drug effects on proliferation, cell cycle kinetics, cytotoxicity and mRNA and protein expressions of cell cycle regulators were tested. The osteogenesis potential of D1-cells were evaluated by testing mRNA expressions of type Ialpha collagen and osteocalcin 2-8 days after treatments, and testing mineralization 1-3 weeks after treatments. The results showed that all the tested drugs suppressed proliferation and arrested cell cycle of D1-cells, but no significant cytotoxic effects was found. Prostaglandin E1, E2 and F2alpha couldn't rescue the effects of AIDs on proliferation. The p27kip1 expression was up-regulated by indomethacin, celecoxib and dexamethasone in both D1-cells and hBMSCs. Higher concentrations of indomethacin and dexamethasone also up-regulated p21Cip1/Waf1 expression in hBMSCs, and so did celecoxib on D1-cells. Expressions of cyclin E1 and E2 were down-regulated by these AIDs in D-cells, while only cyclin E2 was down-regulated by dexamethasone in hBMSCs. All the tested NSAIDs revealed no obvious detrimental effects on osteogenic differentiation of D1-cells. These results suggest that the proliferation suppression of AIDs on BMSCs may act via affecting expressions of cell cycle regulators, but not prostaglandin-related mechanisms.

Vertebral endplate trauma induces disc cell apoptosis and promotes organ degeneration in vitro

There is a major controversy whether spinal trauma with vertebral endplate fractures can result in post-traumatic disc degeneration. Intervertebral discs, which are adjacent to burst endplates, are frequently removed and an intercorporal spondylodesis is performed. In any case, the biological effects within the discs following endplate fractures are poorly elucidated to date. The aim of our investigations was therefore to establish a novel disc/endplate trauma culture model to reproducibly induce endplate fractures and investigate concurrent disc changes in vitro. This model is based on a full-organ disc/endplate culture system, which has been validated by the authors before. Intervertebral disc/endplate specimens were isolated from Burgundy rabbits and cultured in standard media (DMEM/F12, 10%FCS). Burst endplate fractures were induced in half of the specimens with a custom-made fracture device and subsequently cultured for 9 days. The biological effects such as necrotic or apoptotic cell death and the expression of pro-apoptotic genes and other genes involved in organ degeneration, e.g. matrix metalloproteinases (MMPs) were analyzed. Cell damage was assessed by quantification of the lactate dehydrogenase (LDH) activity in the supernatant. The expression of genes involved in the cellular apoptotic pathway (caspase 3) and the pro-apoptotic proteins FasL and TNF-alpha were monitored. The results demonstrate that LDH levels increased significantly post trauma compared to the control and remained elevated for 3 days. Furthermore, a constant up-regulation of the caspase 3 gene in both disc compartments was present. The pro-apoptotic proteins FasL and TNF-alpha were up regulated predominantly in the nucleus whereas the MMP-1 and -13 transcripts (collagenases) were increased in both disc structures. From this study we can conclude that endplate burst fractures result in both necrotic and apoptotic cell death in nucleus and annulus tissue. Moreover, FasL and TNF-alpha expression by nucleus cells may lead to continued apoptosis induced by Fas- and TNF-alpha receptor bearing cells. In addition TNF-alpha over-expression has potentially deleterious effects on disc metabolism such as over-expression of matrix proteinases. Taken together, the short term biological response of the disc following endplate fracture exhibits characteristics, which may initiate the degeneration of the organ.

Effects of non-steroidal anti-inflammatory drugs on cell proliferation and death in cultured epiphyseal-articular chondrocytes of fetal rats

Previous reports indicated that non-steroidal anti-inflammatory drugs (NSAIDs) suppress bone repair. Our previous study further found that ketorolac delayed the endochondral bone formation, and the critical effective timing was at the early stage of repair. Furthermore, we found that NSAIDs suppressed proliferation and induced cell death of cultured osteoblasts. In this study, we hypothesized that chondrocytic proliferation and death, which plays an important role at the early stage of endochondral bone formation, might be affected by NSAIDs. Non-selective NSAIDs, indomethacin, ketorolac, diclofenac and piroxicam; cyclooxygenase-2 (COX-2) selective NSAIDs, celecoxib and DFU (an analog of rofecoxib); prostaglandins (PGs), PGE1, PGE2 and PGF2alpha; and each NSAID plus each PG were tested. The effects of NSAIDs on proliferation, cell cycle kinetics, cytotoxicity and cell death of epiphyseal-articular chondrocytes of fetal rats were examined. The results showed that all the tested NSAIDs, except DFU, inhibited thymidine incorporation of chondrocytes at a concentration range (10(-8) to 10(-4)M) covering the theoretic therapeutic concentrations. Cell cycle was arrested by NSAIDs at the G(0)/G(1) phase. Upon a 24h treatment, LDH leakage and cell death (both apoptosis and necrosis) were significantly induced by the four non-selective NSAIDs in chondrocyte cultures. However, COX-2 inhibitors revealed non-significant effects on cytotoxicity of chondrocytes except higher concentration of celecoxib (10(-4)M). Replenishments of PGE1, PGE2 or PGF2alpha could not reverse the effects of NSAIDs on chondrocytic proliferation and cytotoxicity. In this study, we found that therapeutic concentrations of non-selective NSAIDs caused proliferation suppression and cell death of chondrocytes, suggesting these adverse effects may be one of the reasons that NSAIDs delay the endochondral ossification during bone repair found in previous studies. Furthermore, these effects of NSAIDs may act via PG-independent mechanisms. COX-2 selective NSAIDs showed less deleterious effects on chondrocytic proliferation and death.

The Wnt antagonist secreted frizzled-related protein-1 controls osteoblast and osteocyte apoptosis

Mechanisms controlling human bone formation remain to be fully elucidated. We have used differential display-polymerase chain reaction analysis to characterize osteogenic pathways in conditionally immortalized human osteoblasts (HOBs) representing distinct stages of differentiation. We identified 82 differentially expressed messages and found that the Wnt antagonist secreted frizzled-related protein (sFRP)-1 was the most highly regulated of these. Transient transfection of HOBs with sFRP-1 suppressed canonical Wnt signaling by 70% confirming its antagonistic function in these cells. Basal sFRP-1 mRNA levels increased 24-fold during HOB differentiation from pre-osteoblasts to pre-osteocytes, and then declined in mature osteocytes. This expression pattern correlated with levels of cellular viability such that the pre-osteocytes, which had the highest levels of sFRP-1 mRNA, also had the highest rate of cell death. Basal sFRP-1 mRNA levels also increased 29-fold when primary human mesenchymal stem cells were differentiated to osteoblasts supporting the developmental regulation of the gene. Expression of sFRP-1 mRNA was induced 38-fold following prostaglandin E2 (PGE2) treatment of pre-osteoblasts and mature osteoblasts that had low basal message levels. In contrast, sFRP-1 expression was down-regulated by as much as 80% following transforming growth factor (TGF)-beta1 treatment of pre-osteocytes that had high basal mRNA levels. Consistent with this, treatment of pre-osteoblasts and mature osteoblasts with PGE(2) increased apoptosis threefold, while treatment of pre-osteocytes with TGF-beta1 decreased cell death by 50%. Likewise, over-expression of sFRP-1 in HOBs accelerated the rate of cell death threefold. These results establish sFRP-1 as an important negative regulator of human osteoblast and osteocyte survival.

In VivoImaging of Chemotherapy-Induced Apoptosis in Human Cancers

RATIONALE

Induction of apoptosis in sensitive tumor cells is the main mechanism of action of chemotherapy agents in human cancers. Also, the assessment of drug-induced apoptosis soon after chemotherapy may be an early predictor of treatment efficacy.

PATIENTS AND METHODS

A phase I/II study was prospectively conducted in 15 patients presenting with proven lung cancers (n = 10), breast cancers (n = 2), and lymphomas (n = 3) to assess the value of the (99m)Tc-radiolabeled recombinant human (rh) Annexin V for imaging apoptosis immediately after completion of the first course of chemotherapy. Early Annexin V findings post-chemotherapy (day+1, day+2) were also compared to the tumor status at 6 to 12 weeks post-treatment.

RESULTS

All lung and lymphoma patients with an increased tracer uptake post-treatment (n = 8) had either partial or complete tumor response. Five patients with no tracer uptake had progressive disease. However, two breast cancers had a response to treatment, although no significant tracer uptake was observed. Tumor response and survival time were significantly correlated with the (99m)Tc-labeled Annexin V uptake. No serious events related to tracer administration were noted.

CONCLUSION

: Preliminary results of this pilot study demonstrate the feasibility of the 99mTc-labeled Annexin V uptake for the in vivo imaging of apoptosis after one course of chemotherapy. If confirmed on larger series, these promising results may open new perspectives in the management of oncology patients.

DEVELOPMENT OF A CONTINUOUS CELL LINE, PBLE, FROM AN AMERICAN EEL PERIPHERAL BLOOD LEUKOCYTE PREPARATION

A continuous cell line, PBLE, was developed from the adherent cells in a culture of peripheral blood leukocytes from the American eel, Anguilla rostrata. The cells were grown in Leibovitz's L-15 basal medium supplemented with 20% fetal bovine serum (FBS). Under normal culture conditions at 18 degrees C, the morphology of PBLE was fibroblast-like. The cultures have been subcultured over 80 times and have been cryopreserved successfully. These cells have a diploid karyotype of 38 chromosomes, survived temperatures from 5 to 36 degrees C, and proliferated at temperatures from 5 degrees C to at least 30 degrees C. PBLE underwent apoptosis in response to gliotoxin, but did not show a respiratory burst. Results suggest that PBLE may have arisen from a circulating mesenchymal stem cell. PBLE was susceptible to Chum salmon reovirus (CSV) and supported CSV replication. Therefore this cell line should be useful in studying eel specific virus-host interactions.

Apoptotic markers in cancer

In cancer, apoptotic processes occur both spontaneously and induced by antitumor therapies. Qualitative and quantitative changes in cancer cell death along with proliferative alterations are essential determinants in the pathogenesis and progression of malignant disease and its responsiveness to therapy. Besides detecting apoptosis by invasive means in tumor tissue, apoptotic products can be quantified in the circulation. Although circulating apoptotic products usually lack organ and tumor specificity, they contribute in the assessment of disease extent or aggressiveness. The ease of drawing blood facilitates the serial measurement of circulating apoptotic markers to monitor antitumor treatment and predict early response to therapy. This review describes the features of apoptotic and necrotic cell death along with the role the balance between the rates of cell death and cell proliferation plays in the progression of malignancy. The intracellular pathways mediating apoptosis are next summarized. The focus then shifts to the apoptotic markers found in the circulation and their diagnostic, prognostic, predictive, and management utility in cancer.

Nonsteroidal anti-inflammatory drug effects on osteoblastic cell cycle, cytotoxicity, and cell death

Previous studies indicated that nonsteroidal anti-inflammatory drugs (NSAIDs) suppress bone repair, growth, and remodeling in vivo. Our previous in vitro study demonstrated that indomethacin and ketorolac inhibited osteoblast proliferation. In this study, we further investigated the influences of 4 NSAIDs on cell cycle kinetics, cytotoxicity, and cell death pattern in osteoblast cultures from rat fetal calvaria. Our results showed that NSAIDs significantly arrested cell cycle at the G(0)/G(1) phase and induced cytotoxicity and cell death of osteoblasts. Apoptosis was more pronounced than necrosis caused by NSAIDs. Among these NSAIDs, piroxicam showed the least effect to produce osteoblastic dysfunction. Moreover, we found that the cytotoxic and apoptotic effects of NSAIDs on osteoblasts might not be prostaglandin related. These results suggest that the NSAID effects on cell cycle arrest and cell death induction in osteoblasts may be one of the important mechanisms contributing to their suppressive effect on bone formation.

Therapy Control in Oncology by Circulating Nucleosomes

The courses of circulating nucleosomes in the serum of patients with various solid tumors correlate with the clinical outcome after chemo- and radiotherapy. Already during the initial phase of treatment they showed considerable alterations consisting of a rapid increase followed by a decrease during the first therapeutic week. Among patients with advanced lung cancer undergoing chemotherapy, those patients who responded to therapy exhibited less pronounced increases and more complete decreases compared to those patients with insufficient response. In addition, response to therapy was correlated with stronger decreases of the precyclic baseline values from cycle 1 to 2 and from cycle 1 to 3. Thus, circulating nucleosomes are a valuable tool for the early prediction of therapeutic efficacy and can help to modulate therapy strategies early and on an individual basis.

The imaging of apoptosis with the radiolabeled annexin V: optimal timing for clinical feasibility

In recent years, the imaging of drug-induced apoptosis has become one of the centers of interest in experimental and clinical research. In particular, the accurate monitoring of chemosensitivity as well as the early prediction of chemoresistance in response to various pro-apoptotic interventions are critical requirements for the best management of oncology patients. The use of technetium [(99m)Tc]-labeled annexin V on animal and human models of cancers provides a proof of principle for the feasibility of a non-invasive, in vivo detection of an apoptotic signal and then for the early assessment of tumor response in the course of chemotherapy. Although promising, however, the initial clinical data point out on the technical limitations that are still to be resolved in terms of tumor-to-background ratio and optimal timing for the imaging of apoptosis. In the present review article, we report the results of animal studies aimed to the evaluation of apoptotic peaks following chemotherapy. In the light of these basic research works, we analyze the profiles of radiolabeled annexin V uptake over time as observed in clinical trials. We then discuss possible new imaging strategies designed to optimize the visualization of apoptotic changes within tumor tissues using the [(99m)Tc]-labeled annexin V. We also suggest longer lived forms of radiolabeled annexin V designed to better understand the temporal patterns of apoptotic tumor response, which in turn, may help to capture the best time-window for the imaging of cell death.

Thyrotropin effects on ultraviolet radiation-dependent apoptosis in FRTL-5 cells

Apoptosis plays an important role within the endocrine system, particularly in the thyroid gland, although little is known about its regulation in normal thyroids. Because thyrotropin (TSH) regulates many thyroid-specific functions and cell proliferation, we investigated whether TSH can influence such mechanisms. To induce apoptosis we used UV-C radiation. The FRTL-5 rat thyroid cell strain, a cloned strain of differentiated and untransformed cells that reproduces many of the characteristics of the normal thyroid was chosen for this study. The FRTL-5 cells are a particularly suitable model because they actively proliferate when cultured in the presence of TSH (6H medium), while in TSH-free medium (5H medium) cells remain in a physiologic quiescent state for a long period of time. FRTL-5 cells in both culture conditions were irradiated with UV-C radiation (254 nm wavelength). At 48 hours after radiation, 6H cultured cells showed the characteristic signs of apoptosis. However, 5H cultured cells did not present macroscopic signs of damage, DNA fragmentation, or detectable apoptosis. Furthermore, the expression of 23 apoptosis-related genes was compared. Results indicate that Bcl2 and caspase-2 expression is enhanced, while bax, GADD45 and mdm-2 expression is reduced in irradiated cells. These data confirm that TSH plays a major role in regulating UV-induced apoptosis in FRTL-5 cells.

Apoptosis in rotator cuff tendonopathy

The aim of this study was to investigate the involvement of apoptosis (programmed cell death) in the pathogenesis of rotator cuff disorders. The edges of torn supraspinatus rotator cuff tendons were collected from patients with rotator cuff tear (n = 25). Samples of the intra-articular portion of subscapularis tendons were collected from patients without rotator cuff tear as control (n = 6). To minimize individual variance, we also collected six pairs of supraspinatus tendon and subscapularis tendon from six patients with rotator cuff tears. Apoptosis was detected by in situ DNA end labelling assay and DNA laddering assay. Immunohistochemical staining was performed to identify cells undergoing apoptosis. Control subscapularis tendon had normal morphology. Tendon from torn supraspinatus rotator cuff showed significant mucoid degeneration. Within the areas of degeneration, there were large numbers of apoptotic cells. The percentage of apoptotic cells in the degenerative rotator cuff (34%) was significantly higher than that in controls (13%) (p < 0.001). The excessive apoptosis detected in degenerative rotator cuff tissue was confirmed by DNA laddering assays. This is the first report of excessive apoptosis in degenerating rotator cuff tendon. Cells undergoing apoptosis in rotator cuff were mainly fibroblast-like cells. These finding indicate that apoptosis may play an important role in the pathogenesis of rotator cuff degeneration.

Induction of apoptosis in cerebellar granule cells by 2,4-dichlorophenoxyacetic acid

2,4-Dichlorophenoxyacetic acid (2,4-D) and derivatives are herbicides widely used in Argentina and other parts of the world. Exposure to 2,4-D, its ester and salt formulations, have been associated with a range of adverse health effects in humans and different animal species, from embryotoxicity and teratogenicity to neurotoxicity. In this work, we demonstrate that after 24 hs of treatment with 1 and 2 mM 2,4-D there is an induction of apoptosis in cerebellar granule cells (CGC) in culture. However, with 2 mM 2,4-D one population of CGC developed features of apoptosis while another appeared to die by necrosis. This process is associated with an increase in caspase-3 activity after 12 hs of treatment with the herbicide, which is preceded by cytochrome c release from the mitochondria. Treatment of CGC with 2,4-D appears to induce apoptosis by a direct effect on mitochondria producing cytochrome c release and consequently activation of caspase-3, being mitochondrial damage sufficient for triggering the events that may cause apoptosis.

The mycotoxin deoxynivalenol affects nutrient absorption in human intestinal epithelial cells

Deoxynivalenol (DON) is a mycotoxin belonging to the tricothecene family that has many toxic effects in animals, including diarrhea and weight loss. Using the human epithelial intestinal cell line HT-29-D4 as an in vitro model, we studied the effect of DON on the uptake of different classes of nutrients, including sugars, amino acids and lipids. At low concentrations (below 10 micro mol/L), DON selectively modulated the activities of intestinal transporters: the D-glucose/D-galactose sodium-dependent transporter (SGLT1) was strongly inhibited by the mycotoxin (50% inhibition at 10 micro mol DON, P < 0.05), followed by the D-fructose transporter GLUT5 (42% inhibition at 10 micro mol/L, P < 0.001), active and passive L-serine transporters (30 and 38% inhibition, respectively, at 10 micro mol/L, P < 0.05). The passive transporters of D-glucose (GLUT) were slightly inhibited by DON (15% inhibition at 1 micro mol/L, P < 0.01), whereas the transport of palmitate was increased by 35% at 10 micro mol/L DON (P < 0.001). In contrast, the uptake of cholesterol was not affected by the mycotoxin. At high concentrations (100 micro mol/L), SGLT1 activity was inhibited by 76% (P < 0.01), whereas the activities of all other transporters were increased. The selective effects of DON on intestinal transporters were mimicked by cycloheximide and deoxycholate, suggesting that inhibition of protein synthesis and induction of apoptosis are the main mechanisms of DON toxicity in intestinal cells.

Amelioration of myocardial global ischemia/reperfusion injury with volume-regulatory chloride channel inhibitors in vivo

BACKGROUND

Recently, the apoptotic volume decrease was suggested to be regulated by volume regulatory Cl- channels in cultured cell lines. We thus examined whether inhibition of volume-regulatory Cl- channels is cardioprotective, like caspase inhibition, by hindering the apoptosis of cardiomyocytes induced by global ischemia/reperfusion (I/R) in vivo.

METHODS

We performed global ischemia for 8 min at 37 degrees C or 4 degrees C in isolated rat hearts, followed by 24-hr reperfusion via heterotopic heart transplantation. The heart tissue was examined by means of the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method, genomic DNA electrophoresis, and caspase-3 activity. Two blockers of volume-regulatory Cl- channels, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), and a broad-spectrum caspase inhibitor, benzoyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene (Z-Asp-DCB), were administered intravenously. Triphenyltetrazolium chloride (TTC) staining and ultrasound cardiography were performed to examine myocardial viability. The TTC-unstained region was assessed by means of horseradish peroxidase (HRP) infiltration and the TUNEL method.

RESULTS

The transplanted hearts showed TUNEL-positivity and DNA laddering with a peak at 24 hr during reperfusion after ischemia at 37 degrees C, but not at 4 degrees C. NPPB and DIDS were as potent as Z-Asp-DCB for recovery of cardiac function and for blocking the appearance of TUNEL-positivity, DNA laddering, caspase 3 activity, and a TTC-unstained area. TTC-unstained areas were composed of either TUNEL- and slightly HRP-positive or TUNEL-negative and strongly HRP-positive cardiomyocytes.

CONCLUSION

The present results demonstrated that myocardial DNA fragmentation, caspase activation, and loss of cardiac function after global I/R were blocked by NPPB and DIDS, similar to in the case of Z-Asp-DCB. These results suggest that inhibition of volume-regulatory Cl- channels is also effective for preventing cardiac I/R injury.

Detection of DNA cleavage in apoptotic cells

At least two discrete deoxyribonuclease activities can be detected during apoptotic death, one that generates 30- to 500-kilobase pair (kbp) domain-sized fragments and another that mediates internucleosomal DNA degradation. The latter nuclease has been identified as the caspase-activated deoxyribonuclease (CAD)/CPAN, a unique enzyme that is normally inhibited by the regulatory subunit ICAD (inhibitor of CAD)/DFF45 (DNA fragmentation factor). In this chapter, techniques widely used to detect DNA cleavage in apoptotic cells, including pulsed-field gel electrophoresis, conventional agarose gel electrophoresis, and terminal transferase-mediated dUTP nick end-labeling (TUNEL), are briefly reviewed. In addition, the use of ICAD to inhibit apoptosis-associated nuclease activity is illustrated. When properly applied, these techniques are widely applicable to the characterization of apoptotic cells.

Cell death induced by MPTP, a substrate for monoamine oxidase B

MPTP is known to cause PD symptoms in primates and in rodents. In order to exert its neurotoxicity MPTP must be converted by monoamine oxidase B into MPP(+) which is the true toxic agent. MPP(+) is taken up by the dopaminergic neurons of the substantia nigra in which it induces cell death. The present work reviews and discusses papers in which specific methods were used to determine whether cell death induced by MPTP/MPP(+) should be considered as apoptosis or necrosis. These two cell death modes may be distinguished using morphological and biochemical criteria. The effect of MPTP/MPP(+) was studied in vitro and in vivo. The results show that no univocal answer is possible. The most widespread interpretation is that MPTP/MPP(+) causes apoptosis when its neurotoxic effect is only sligh and necrosis when it is stronger. Similar considerations may be made also concerning the type of cell death occurring in the dopaminergic neurons in the substantia nigra of PD patients.

Glutathione depletion causes cell growth inhibition and enhanced apoptosis in pancreatic cancer cells

BACKGROUND

Recent studies have demonstrated that various tumors express enhanced levels of the radical scavenger glutathione (GSH). Moreover, there are grounds for claiming that GSH plays a crucial role in cell proliferation and tumor resistance. In the current study, we investigated the relation between cell growth and GSH levels in the pancreatic adenocarcinoma cell line, AsPC-1, and the significance of GSH in tumor resistance to chemotherapy.

METHODS

Cell growth in AsPC-1 was initiated through transforming growth factor-alpha (TGF-alpha) or fetal calf serum (FCS). Then, cell cycle, cell proliferation, and cellular GSH content were analyzed at different times in the presence or absence of buthionine sulfoximine (BSO). The impact of GSH on chemotherapy-induced apoptosis was studied using 5-fluorouracil or melphalan in the presence or absence of BSO. Finally, we compared the GSH content of 15 pancreatic tumor specimens with 10 normal pancreatic tissue specimens.

RESULTS

Analysis of GSH in pancreatic tissues demonstrated increased GSH levels in cancerous compared with normal tissue (17.5 +/- 2.3 vs. 8. 8 +/- 1.4 nmol/mg protein; P < 0.004). Incubation of AsPC-1 with TGF-alpha or FCS resulted in cell proliferation and cell cycle activity, whereas GSH content was not altered. Incubation of GSH-depleted cells with TGF-alpha did not stimulate cell growth. In addition, GSH-depletion resulted in an increased rate of apoptosis after melphalan (6.3 +/- 0.3 % vs. 11.2 +/- 0.3 %; P < 0.001), but not after 5-fluorouracil treatment.

CONCLUSIONS

Taken together, our results show enhanced GSH levels in pancreatic carcinoma and an essential role of GSH in cell proliferation and in resistance of AsPC-1 cells. Therefore, GSH-depletion may improve the efficacy of adjuvant therapy in pancreatic carcinoma.

Tumor necrosis factor alpha mediates apoptosis of brown adipocytes and defective brown adipocyte function in obesity

Severe quantitative and qualitative brown adipocyte defects are common in obesity. To investigate whether aberrant expression of tumor necrosis factor alpha (TNF-alpha) in obesity is involved in functional brown fat atrophy, we have studied genetically obese (ob/ob) mice with targeted null mutations in the genes encoding the two TNF receptors. The absence of both TNF receptors or p55 receptor alone resulted in a significant reduction in brown adipocyte apoptosis and an increase in beta(3)-adrenoreceptor and uncoupling protein-1 expression in obese mice. Increased numbers of multilocular functionally active brown adipocytes, and improved thermoregulation was also observed in obese animals lacking TNF-alpha function. These results indicate that TNF-alpha plays an important role in multiple aspects of brown adipose tissue biology and mediates the abnormalities that occur at this site in obesity.

Prostatic disorders in the dog

Common canine prostatic disorders include benign prostatic hypertrophy (BPH), prostatitis, prostatic cysts and prostatic adenocarcinoma. BPH is a spontaneous and age-related disorder of intact male dogs, which occurs in more than 80% male dogs over 5 years of age, and which is associated with clinical signs of sanguinous prostatic fluid, constipation and dysuria. BPH signs respond to castration or to finasteride treatment (0.1-0.5 mg/kg per os once daily), as finasteride inhibits conversion of testosterone to dihydrotestosterone, causing prostatic involution via apoptosis. BPH often occurs concurrently with prostatic infection, abscessation, cysts and neoplasia in the intact dog, and finasteride-induced prostatic involution may be beneficial in treatment of all of these conditions except neoplasia. Two studies suggest that risk of prostatic adenocarcinoma is increased in neutered, compared to intact male dogs. Although canine prostatic neoplasia, unlike human prostatic neoplasia, usually does not respond to androgen deprivation, recent reports of prostatic intraepithelial neoplasia (PIN) in a high percentage of older male dogs, with and without prostatic adenocarcinoma, suggests that PIN may be a precursor to adenocarcinoma in the dog as it is believed to be in man.

Pathologic assessment of myocardial cell necrosis and apoptosis after ischemia and reperfusion with molecular and morphological markers

The present work illustrates the critical subcellular changes in the rat heart after 10-30 min of left coronary artery (LCA) occlusion and 120 min of reperfusion with a combination of several staining techniques. Triphenyltetrazolium chloride (TTC) to detect non-injured myocytes, horseradish peroxidase (HRP) and terminal deoxynucleotide nick-end labeling (TUNEL) to detect necrotic and apoptotic cells were employed and electron microscopy (EM) was used to validate these changes. After 20 min of LCA occlusion, myocytes began to undergo necrosis whilst after 10 min occlusion, no myocyte underwent irreversible cell injury in the risk area. After 30 min of LCA occlusion and 120 min reperfusion, 36.3, 26.6 and 25% cells were normal, necrotic, and reversibly injured, respectively; the remaining 12.8% cells were apoptotic. Necrotic cells were strongly positive with HRP and negative for TTC and TUNEL. TUNEL-positive or apoptotic cells were slightly HRP-positive, indicating altered cell membrane permeability. Reversibly-injured myocytes were TTC-, HRP- and TUNEL-negative. These changes were more accurately defined in the 100- microm thick sections than in the traditional slices. It is concluded that: (1) TTC-staining of 100- microm thick sections is far superior and accurate for the detection of ischemic changes with shorter period of ischemia (10 min); (2) the combination of TTC-staining, HRP reaction and TUNEL method is excellent for demarcation of early ischemic changes; (3) TTC-negativity in ischemia less than 20 min does not indicate necrosis but only represents reversible changes; (4) the apoptosis is absent in early ischemia of 20 min with or without reperfusion at a time when sufficient ATP is present, and appears only after 30 min of coronary ligation and reperfusion; and (5) the apoptotic cells lose membrane integrity accompanied by decreased glycocalyx thickness and cell swelling as opposed to commonly known characteristics of apoptotic cells.

The use of flow cytometry to measure neutrophil function

Neutrophils are important professional phagocytic cells that provide the host with a first line of defense against acute bacterial and fungal diseases and recurrent, severe or unusual infections are associated with inherited defects of neutrophil function. Furthermore, abundant evidence links inappropriate neutrophil-mediated tissue damage to the pathogenesis of conditions such as acute respiratory distress syndrome, septicemia with multiorgan failure, ischemia-reperfusion injury and rheumatoid arthritis. Flow cytometry has been increasingly used to evaluate the functional capabilities of neutrophils. In this review, we discuss the use of flow cytometry to assess neutrophil functional responses including calcium mobilization, F-actin assembly, adhesion, aggregation, degranulation, phagocytosis and reactive oxygen species (ROS) production. The use of flow cytometry to identify neutrophil priming is also discussed. The advantage of flow cytometry is that the majority of neutrophil functions can be measured using a small volume of whole blood that reduces artifactual changes in function caused by purification procedures. The advent of numerous new fluorochromes and multiparametric analysis allows the simultaneous measurement of several neutrophil functions in the same population of cells. Flow cytometric analysis provides a rapid screen for abnormalities of neutrophil function and reflects more accurately their behavior in vivo.

Characterization of cadmium-induced apoptosis in rat lung epithelial cells: evidence for the participation of oxidant stress

The mode of cadmium-induced cell death was investigated in a rat lung epithelial cell line. Cells, grown to near confluence, were exposed to 0-30 microM CdCl2 for 0-72 h. Phase contrast microscopy and fluorescent nuclear staining showed that Cd caused morphological alterations in lung epithelial cells that are characteristic of apoptosis. These changes included cell shrinkage, detachment of the cell from its neighbors, cytoplasmic and chromatin condensation, and fragmentation of the nucleus into multiple chromatin bodies surrounded by remnants of the nuclear envelope. Apoptotic DNA degradation was validated and quantitated using a sensitive enzyme-linked immunosorbent assay (ELISA) which measures the amount of histone-bound DNA fragments in the cytosol. Using this technique, a maximum level of apoptosis (5-fold higher than control) was observed in cultures exposed for 48 h to 20 microM CdCl2. The terminal deoxyribonucleotidyl transferase mediated dUTP nick end labeling method (TUNEL) was subsequently used to determine the percentage of cells that contained Cd-induced DNA strand breaks. After 48 h, approximately 54% of the cells exposed to 20 microM Cd were TUNEL positive compared to less than 2% for control cells. Although the mechanisms by which Cd initiates apoptosis in these cells are presently not known, reactive oxygen species are likely to play a role. This possibility is supported by the finding that the first morphological features indicative of apoptosis were preceded by the up-regulation of oxidant stress genes (glutathione S-transferase-alpha, gamma-glutamylcysteine synthetase, and metallothionein-1), activation of redox sensitive transcription factors (AP-1 and NF-kappaB), and changes in various forms of glutathione (reduced, oxidized, and protein-bound).

Apoptosis. Basic concepts and implications in coronary artery disease

Apoptosis is an active form of cell death that is intricately regulated and distinct from necrosis. Data suggest that apoptosis may play a role in the pathophysiology of coronary atherosclerotic disease. Anatomic evidence of apoptosis has been observed in coronary atherosclerosis, restenosis, and transplant arteriopathy, accompanied by an increase in biochemical and genetic markers of apoptosis. Vasoactive substances such as nitric oxide and angiotensin II also regulate vascular smooth muscle cell apoptosis; vasodilating factors may induce apoptosis, whereas vasoconstricting factors may inhibit apoptosis. The aim of this article is to review key points regarding the detection of apoptosis, its regulation, and its possible role in the pathogenesis of coronary artery disease.

Histochemical demonstration of apoptotic cells in the chicken embryo using annexin V

This study describes the use of biotinylated annexin V for the histochemical detection of apoptotic cells in cultured chicken embryos during gastrulation. This method is based on the Ca2+-dependent binding of annexin V to phosphatidylserine, a negatively charged phospholipid, located at the inner leaflet of the cell membrane in living cells. However, in the early stages of apoptosis, phosphatidylserine is translocated to the outer layer of the cell membrane and can then be recognized by annexin V. Applying this method in cultured chicken embryos during gastrulation, we obtained labelling of apoptotic cells in the three germ layers. In the epiblast and mesoblast, labelling was predominantly present in the region lateral to the primitive streak. At the level of the germinal crescent, labelled cells were also found in the epiblast. Labelled cells in the deep layer, which is a heterogeneous tissue layer composed of endophyll, sickle endoblast and definitive endoblast, were rather scarce. The distribution of cells, as observed in this study after labelling with annexin V in light microscopy and confocal laser scanning microscopy, is consistent with distributions reported by other authors using other approaches and with our previous observations made with the TUNEL technique and by electron microscopy after fixation in a tannic acid-based fixative. The main advantages of this method over other more sophisticated methods is its easiness and rapidity of execution and the fact that both early and late stages of apoptosis are detected.