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Separation of the retina from the retinal pigment epithelium (RPE) is a common form of injury that may occur alone (retinal detachment) or as a result of other blinding disease processes such as age-related macular degeneration or diabetic retinopathy. Despite significant advances in the medical and surgical management of retina–RPE separation, patients often lose vision, primarily due to the death of photoreceptors.1,2 We previously showed that the main event causing photoreceptor death is the activation of the Fas receptor and the downstream cascade of caspases 8, 3, 7, and 9.3–5 Preventing Fas pathway activity provides significant protection against separation-induced death of the photoreceptors. Although Fas-mediated apoptosis is activated rapidly after retina–RPE separation, a surprising number of photoreceptors survive for extended periods of time. This is best exemplified by the clinical observation that patients with retinal detachments affecting central vision generally recover near-normal vision if the detachment is repaired within 1 week.6,7 If repair is delayed beyond 1 week, visual outcomes become significantly poorer. This suggests that early in the course of the detachment, antiapoptotic pathways are activated within the retina to counteract the effect of proapoptotic signals and that they are responsible for the therapeutic window of opportunity for reattachment.8 Autophagy is a complex process that results in the autovacuolization of damaged or redundant cellular components. These vacuoles (i.e., autophagosomes) fuse with lysosomes and their contents are enzymatically degraded and released back into the cell.9 Autophagy activation typically occurs during periods of metabolic stress, usually serving as a cytoprotective process.10 Autophagy has been shown to occur in photoreceptors as part of basal processing of rod outer segments11 as well as in animal models of hereditary retinal degeneration and in models of oxidative stress.12–14 The role of autophagy in these settings is not well defined. We examined the role of autophagy and its control of photoreceptor apoptosis using a well-established rodent model of experimental retina–RPE separation. Our findings demonstrate that retinal detachment results in the activation of autophagy in photoreceptors. Similar to apoptosis, detachment-induced autophagy activity is Fas dependent. In detached retinas, autophagy acts as a prosurvival pathway through negative inhibition of apoptosis. Our data suggest a novel mechanism by which autophagy can be activated and regulate photoreceptor apoptosis.

To evaluate the ability of X-linked inhibitor of apoptosis (XIAP) gene therapy to provide neuroprotection to cells of the outer nuclear layer (ONL) of the retina after retinal detachment.Subretinal injections of a recombinant adenoassociated virus (rAAV) encoding either XIAP or green fluorescent protein (GFP; injection control) were performed in the left eye of Brown Norway rats. Two weeks later, retinal detachments were created at the site of viral injection by delivering sodium hyaluronate into the subretinal space. Retinal tissue was harvested at 24 hours after retinal detachment and was analyzed for caspase 3 and 9 activity. Histologic analysis was conducted on samples taken at 3 days and 2 months after detachment to confirm the presence of XIAP or GFP expression and to assess levels of apoptosis and changes in retinal thickness.Caspase assays performed 24 hours after detachment confirmed an expected increase in caspase 3 and 9 activity in the detached regions of GFP-treated retinas, whereas XIAP-treated detached retinas behaved comparably to attached controls. TUNEL analysis of 3-day tissue samples showed fewer apoptotic cells in XIAP-treated detachments than in GFP-treated detachments. At 2 months after the detachment, histology and immunohistochemistry confirmed the preservation of the ONL at sites of XIAP overexpression, whereas the GFP-treated detached retinas had significantly deteriorated.The results suggest that XIAP confers structural neuroprotection of photoreceptors for at least 2 months after retinal detachment.

This study is to explore the inhibitory effect of methyl jasmonate on cell proliferation and expression of XIAP and survivin of human neuroblastoma cell line BE(2)-C. After cultivation of 1 - 2 mmol x L(-1) jasmonates with BE (2) -C cells for 6 - 24 h, the growth inhibiting rates of BE (2) -C cells were studied by MTT colorimetry. Cell proliferation was detected by colony formation assay. Cell cycle phases were assayed by propidium iodide staining flow cytometery. Cell apoptosis was inspected by acridine orange-ethidium bromide fluorescent staining, Hoechst 33258 fluorescent staining, and Annexin V-FITC and propidium iodide staining flow cytometry. Expressions of cyclin D1, XIAP and survivin were determined by RT-PCR and real-time RT-PCR. Methyl jasmonate inhibited the growth of BE(2)-C cells in a dose- and time-dependent manner. After addition of 1, 1.5 and 2 mmol x L(-1) of methyl jasmonate for 24 h, the inhibiting rates of cell growth reached 20.6% - 85.5% (P0.01), and the IC50 was 1.35 mmol x L(-1). The cell cycles were arrested at S phase. A part of cells presented the characteristic morphological changes of apoptosis. The early apoptotic rates were 13.51%, 17.32%, 24.59% (P0.01) and the cell death rates were 29.36% , 54.73% , 75.52% (P0.01), respectively. The expression of XIAP and survivin mRNA were downregulated by 18.5% - 68.9% , 22.4% - 48.7% (P0.05), respectively, without change in that of cyclin D1. The results indicated that methyl jasmonate could significantly inhibit the growth of BE(2) -C cells through inducing cell cycle arrest and apoptosis, downregulating the expression of XIAP and survivin might be one of its molecular mechanisms of action.

Recent evidence has indicated that members of natural jasmonates, a family of plant stress hormones, exhibit anticancer activity. The current study was undertaken to investigate the effects of jasmonates on the in vitro growth of human neuroblastomas, one of the most common solid tumors in children.Cellular proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide colorimetry and colony formation assay. Apoptosis was detected by Hoechst 33258 staining and flow cytometry. Western blotting was applied to assay gene expression.The administration of natural jasmonates, methyl jasmonate, cis-jasmone, and jasmonic acid to cultured neuroblastoma cell line SH-SY5Y, resulted in a decrease of cell proliferation in a doseand time-dependent manner. However, the in vitro growth of cultured human embryonic kidney (HEK) cell line HEK 293 was not affected by jasmonates. The cell cycles of jasmonate-treated SH-SY5Y cells were arrested at the G2/M phase. The incubation of SH-SY5Y cells with jasmonates resulted in characteristic changes of apoptosis. The anticancer activities of natural jasmonates on SH-SY5Y cells are as follows: methyl jasmonatecis-jasmonejasmonic acid. In addition, the expressions of proliferating cell nuclear antigen and N-myc were downregulated by methyl jasmonate. Moreover, methyl jasmonate decreased the expression of the Xlinked inhibitor of apoptosis protein and survivin, critical members of inhibitors of the apoptosis protein family, in SH-SY5Y cells.Jasmonates suppress the growth of human neuroblastoma cell line SH-SY5Y via inhibiting cell proliferation and inducing apoptosis, which lays the groundwork for further investigation into the anticancer activities and its mechanisms of natural jasmonates on human neuroblastomas.

Retinal detachment (RD), defined as the separation of the neurosensory retina from subjacent retinal pigment epithelium (RPE), results in the apoptotic death of photoreceptor cells.1-4 Rodent and feline models of RD have demonstrated the activation of proapoptotic pathways nearly immediately after the retina becomes separated from the RPE.1-4 Histologic markers of apoptosis, such as terminal deoxynucleotidyl transferase nick-end label (TUNEL) staining, reach a peak at approximately 3 days after RD, with apoptotic activity and progressive cell death persisting for the duration of the detachment period. Clinical experience in the repair of retinal detachments, however, has demonstrated that there is a window of opportunity for repair with preservation of good visual acuity. Retrospective case series have demonstrated that significant numbers of patients with macula-off RDs repaired within 5 to 10 days after onset of detachment can retain relatively good visual function but that visual acuity drops significantly as the time between detachment and repair extends.5-7 The delayed time between the activation of proapoptosis pathways and the clinical onset of visual loss suggests that intrinsic neuroprotective factors may become activated within the neural retina and may serve to counterbalance the effects of the proapoptotic pathways activated by retinal–RPE separation. Previous work in our laboratory using gene microarray analysis of experimental detachment in rats revealed the increased expression of genes involved in stress–response pathways.8 Of particular interest was the increased transcription and translation of interleukin (IL)-6 and downstream components of its associated signal transduction pathway. IL-6 is a pleiotropic cytokine with a role in inflammation, hematopoiesis, angiogenesis, cell differentiation, and neuronal survival.9-11 In the central nervous system, IL-6 is synthesized by microglia, astrocytes, and neurons.12,13 In the retina, IL-6 is synthesized by Muller cells and the RPE.14,15 A neuroprotective role for IL-6 has been previously suggested in different models of ocular injury. In rat models of retinal ischemia–reperfusion injury, IL-6 protein levels are upregulated within 8 hours after injury.16 Furthermore, intravitreal injection of exogenous IL-6 immediately after ischemia–reperfusion injury or before N-methyl-d-aspartate (NMDA)-induced toxicity increases survival of retinal ganglion cells.16,17 In vitro studies have shown that IL-6 increases the duration of rat retinal ganglion cell survival in primary tissue culture.18,19 Collectively, these data suggest that IL-6 upregulation after injury may serve to function as a neuronal survival factor. The goal of this study is to test the hypothesis that IL-6 functions as an inhibitor of photoreceptor apoptosis after RD. Understanding the effect of IL-6 on photoreceptor survival may provide insight into potential therapeutic strategies for protecting photoreceptors during periods of photoreceptor–RPE separation.

Objective To determine whether inhibiting the Fas proapoptosis pathway will result in increased photoreceptor survival after separation of the retina from the retinal pigment epithelium (RPE). Methods Retina/RPE separation was induced in rat and mouse eyes by the subretinal injection of hyaluronic acid, 1%. Fas-pathway signaling was inhibited by the concomitant injection of a Fas receptor–neutralizing antibody, small inhibitory RNA against the Fas-receptor transcript (siFAS), or the use of the Fas-receptor defective mouse strain LPR. Indices of photoreceptor death included terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining, cell counts, and retinal thickness measurements. Retinas were immunostained with antibodies against rhodopsin and cone opsin to evaluate rod and cone photopigment production, respectively. Results Inhibition of Fas signaling using Fas receptor–neutralizing antibody, siFas, or LPR mice resulted in a significant reduction in the number of TUNEL-positive photoreceptor cells as well as in a significant preservation of outer nuclear layer cell counts and thickness as compared with retina/RPE separation in eyes with intact Fas signaling. Fas-pathway inhibition resulted in preservation of both rhodopsin- and cone opsin–positive cells. Conclusions Inhibition of the Fas proapoptosis pathway results in significant photoreceptor preservation after retinal separation from the RPE. Clinical Relevance Fas-pathway inhibition might serve as a novel mechanism for preserving photoreceptor cells during retinal disease.

To investigate the effects of overexpression of second mitochondria-derived activator of caspases (Smac) gene on apoptosis of gastric cancer cells.Under the induction of liposome, MKN-45 cells were transfected by Smac gene and incubated with G418 for subclone selection. Reverse transcriptase-polymerase chain reaction and Western blot were used to determine cellular Smac gene expression. After induction of apoptosis by mitomycin (MMC), cell viabilities were analyzed using trypan blue stain. Apoptosis was measured by electronic microscopy, acridine orange-ethidium bromide fluorescent staining and in situ terminally labelled transferase technique (TUNEL). Western blot and colorimetry were used to assess cellular caspase-3 expression and its activity.The Smac mRNA and protein levels in MKN-45/Smac subclone cells (subclone consistently expressing Smac gene) were significantly higher than those in MKN-45 (P0.01). When compared with those in MKN-45, cell viabilities of MKN-45/Smac were reduced by 10.0% to 30.8% (P0.01), after treatment with 10 microg/ml MMC for 6 to 24 hours. Some of the MKN-45/Smac cells showed characteristic morphologic changes of apoptosis, their apoptotic rate being increased by 21.2% (P0.01). After treatment with MMC, caspase-3 expression and its activity in MKN-45/Smac cells were significantly higher than those in MKN-45 (P0.01).Overexpression of Smac in gastric cancer cell line significantly improves expression and activity levels of caspase-3 after induction by MMC. Such apoptosis-inducing effect establishes a novel strategy for regulating the apoptosis activity of gastric cancer.

The second mitochondria-derived activator of caspases (Smac) is a novel proapoptotic gene, which plays an important role in the apoptosis-inducing effects of irradiation on tumor cells. The purpose of this study was to investigate the effects of extrinsic Smac gene transfer and its over-expression in radiotherapeutic sensitivities of cervical cancer cells.After the Smac gene was transferred into the cervical cancer cell line HeLa, subcloned cells were obtained by persistent G418 selection. Cellular Smac gene expression was detected by RT-PCR and Western blot, while in vitro cell viabilities were detected by trypan blue staining assay. After treatment with X-ray irradiation, cellular radiotherapeutic sensitivities were investigated by tetrazolium bromide colorimetry. Cellular apoptosis and its rate were determined by electronic microscopy, annexin V-FITC and propidium iodide staining flow cytometry. The expression and activities of cellular caspase-3 were assayed by Western blot and colorimetry.Smac mRNA and protein levels in HeLa/Smac cells and the selected subclone cell line of cervical cancer were significantly higher than those of HeLa (P0.01). There was no significant difference in cellular viabilities between them (P0.05). However, after irradiation with 8 Gy X-ray, growth activities of HeLa/Smac were reduced by 22.42% (P0.01). When compared with those of HeLa, partial HeLa/Smac cells presented characteristic morphological changes of apoptosis under electronic microscope, with higher apoptosis rates (16.4% vs. 6.2%, P0.01); the caspase-3 expression levels in HeLa/Smac cells were improved significantly (P0.01), while its activities were increased by 3.42 times (P0.01).Stable transfer of the extrinsic Smac gene and its over-expression in cervical cancer cell line could significantly enhance the expression and activities of cellular caspase-3 and ameliorate apoptosis-inducing effects of irradiation on cancer cells, which was a novel strategy to improve radiotherapeutic effects on cervical cancer.

Abnormal apoptosis is one of the key factors for drug resistance of neoplasms. Smac, a novel gene involved in regulation of apoptosis,plays an important role in tumor cell apoptosis induced by chemotherapeutic drugs. This study was designed to explore the effects of overexpressed Smac gene on chemotherapeutic sensitivity of gastric cancer cell line.By liposome GeneSHUTTLE-40, Smac gene was transfected into gastric cancer cell line MKN-45. Cellular Smac gene expression were determined by reverse transcription-polymerase chain reaction (RT-PCR)and Western blot analysis. Cisplatin (1, 5, 10 microg/ml), mitomycin C (0.1,1,10 microg/ml), and curcumin (10, 20, 40 micromol/L) were selected to treat untransfected and transfected MKN-45 cells. Cellular proliferation activities were assayed by tetrazolium bromide (MTT) colorimetry. The morphological changes of cancer cells were observed under inverted microscope. Cellular apoptosis was determined by Annexin V-FITC and propidium iodide staining flow cytometry.Compared with untransfected control group,Smac mRNA and protein levels in transfected MKN-45 cells were significantly increased (P0.01). The growth inhibition rates of MKN-45 cells treated with various concentration of cisplatin, mitomycin C, and curcumin on MKN-45 cells were increased by 10.10%-23.80% (P0.01), 10.01%-15.86% (P0.01), 11.28%-22.12% (P0.01), respectively, with the cells becoming round, obviously refracted, and fragmented. The cellular apoptosis rates were increased by 6.7%-20.2% (P0.01), 5.4%-13.2% (P0.01), and 10.6%-20.1% (P0.01), respectively.Transfection of extrinsic Smac gene results in its over-expression in MKN-45 cells,which could increase the chemotherapeutic sensitivity of MKN-45 cells.

Curcumin is the major effective component of curcuma, which is a kind of traditional Chinese medicine. It has been paid more attention to curcumin recently for its specific proliferation inhibition and apoptosis inducing effects on tumor cells; however, the involved mechanisms were not clear. This study was designed to explore the apoptosis inducing effects of curcumin on human ovary A2780 cell line and its related molecular mechanisms.A2780 cancer cells were treated with 10-50 mumol/L curcumin for 6-24 h and the growth inhibition rates of A2780 cancer cells were measured by MTT method. Cell apoptosis was inspected by flow cytometry (FCM) and acridine orange-ethidium bromide fluorescent staining method. The protein levels of NF-kappa B (P65) and Caspase-3 in cancer cells were observed by SP immunohistochemistry.The growth inhibition rates of the cancer cells reached 62.05%-89.24%, with the peak of sub G1 appeared on DNA histogram in FCM. Partial cells presented the characteristic morphological changes of apoptosis under the fluorescent microscope; the apoptosis rates were 21.5%-33.5%. The NF-kappa B (p65) expression was decreased while Caspase-3 expression was increased, which depended on the action time.Curcumin could significantly inhibit the growth of ovary cancer cells; inducing apoptosis through up-regulating Caspase-3 and down-regulating expression of NF-kappa B was probably one of its molecular mechanisms.

Purpose. To test the effect of a small peptide inhibitor (Met12) of the Fas receptor on the activation of extrinsic and intrinsic apoptosis pathways after retinal detachment. Methods. Retinal-RPE separation was created in Brown Norway rats by subretinal injection of 1% hyaluronic acid. Met12, derived from the Fas-binding extracellular domain of the oncoprotein Met, was injected into the subretinal space at the time of separation. A mutant peptide and vehicle administered in a similar fashion acted as inactive controls. The extrinsic apoptotic pathway was induced in 661W cells using a Fas-activating antibody in the presence or absence of Met12. Caspase 3, caspase 8, and caspase 9 activities were measured with calorimetric and luminescent assays in retinal extracts and cell lysates. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) was performed in retinal sections 3 days after separation. Histology was performed in retinal sections 2 months after retinal detachment. Results. Met12 inhibited Fas-induced caspase 8 activation in 661W cells. Similarly, administration of Met12 into the subretinal space inhibited the activation of caspase 3, caspase 8, and caspase 9 after retinal detachment. This corresponded to a decreased level of TUNEL-positive staining of photoreceptors after retinal-RPE separation in animals that received Met12, but not inactive mutant, peptide treatment. After 2 months, the outer nuclear layer was significantly thicker, and the photoreceptor count was higher in animals treated with subretinal Met12. Conclusions. The small peptide Met12 may serve as a photoreceptor-protective agent in the setting of retinal-RPE separation.

PURPOSE. To determine whether the FAS-mediated apoptosis pathway becomes activated in the retina after retinal detachment and to investigate the temporal relationship between the activation of the FAS-pathway and the intrinsic apoptosis pathway involving caspase-9 and cytochrome c. METHODS. Experimental retinal detachments were created in Brown-Norway rats by injecting 10% hyaluronic acid into the subretinal space. Retinal tissue was harvested at 2, 4, 8, 24, 72, and 168 hours after creation of the detachment. Immunoprecipitation was performed to assess for FAS-receptor/FAS-ligand complex formation, and activation of caspase-8 and BID (a member of the Bcl-2 family of proteins) was assessed by Western blot analysis. A caspase-9 activity assay and immunoprecipitation of the caspase-9/cytochrome c complex were performed at these same time points. Specific pathway inhibition was performed with the caspase-9 inhibitor zLEHD.fmk or neutralizing antibodies against either the FAS-receptor or FAS-ligand. Transcription levels of FAS and intrinsic pathway intermediates were assessed as a function of time after retinal detachment by using quantitative real-time polymerase chain reaction. RESULTS. Retinal detachment resulted in the time-dependent formation of the FAS-receptor/FAS-ligand complex that preceded the peak of caspase-9 activity and caspase-9/cytochrome c complex formation. Cleavage of caspase-8 and truncation of BID were also observed. Injection of zLEHD.fmk into the subretinal space of a detached retina resulted in decreased caspase-9 activity, as did injection of anti-FAS-receptor antibody into either the subretinal space or the vitreous. Retinal detachment resulted in the transcriptional upregulation of the FAS-receptor, FAS-ligand, caspase-8 and BID, but not caspase-9 and cytochrome c. CONCLUSIONS. The FAS-mediated apoptosis pathway becomes activated and transcriptionally upregulated after retinal detachment. The peak of FAS activation precedes that of the intrinsic pathway, and inhibition of FAS activation can decrease caspase-9 activity.

AIM: To explore the apoptosis-inducing effects of extrinsic BAK gene transfer and its over-expression on gastric cancer cells and its molecular mechanisms. METHODS: The eukaryotic expression for BAK gene was constructed and transferred into gastric cancer MKN-45 cell line. After being transferred for 1 to 5 days, cellular BAK gene expression was detected by RT-PCR and Western blotting methods. The growth activities of cancer cells were detected by cell count and MTT colorimetry. Cell cycle changes were assayed by flow cytometry. Cellular apoptosis was assayed by electronic microscopy and in situ terminally labeled transferase technique (TUNEL). Cellular caspase-3 activities were observed by colorimetric method. RESULTS: After being transferred for 1 to 5 days, cellular BAK mRNA and protein expression levels were significantly increased (P

The role of Fas ligand (FasL) in tumor immune privilege is controversial. In this study, 22 human tumor cell lines reported to be FasL+ were reevaluated by Western blot analysis, ELISA, and a functional assay. None of the cells lines expressed FasL. To assess whether human tumors express FasL in vivo, susceptibility to FasL-mediated killing was evaluated. About 75% of the 22 tumors tested were sensitive to FasL-mediated apoptosis, suggesting, therefore, that only about 25% could possibly express FasL. To investigate whether "FasL+" human tumor cells could suppress the proinflammatory effects of FasL in vivo, FasL transfectants were generated from two prototype "FasL+" tumor cell lines. The transfectants expressing FasL were rejected by SCID mice. In contrast, all the mice inoculated with parental tumor cells developed large tumors. These results suggested that human tumor cells that express FasL and resist both FasL-mediated apoptosis and inflammation are rare or nonexistant. We concluded that FasL expression is not a main mechanism that tumors use to counteract antitumor immunity.