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Bladder cancer is a clinically heterogeneous disease with a poor prognosis. In the current study, anti-proliferation assay of a Euphorbiaceae diterpenoid library led to the identification of an anti-bladder cancer agent Jolkinolide B (JB). JB showed significant cytotoxicity against a panel of bladder cancer cell lines and suppressed the growth of cisplatin (CDDP)-resistant bladder cancer xenografts in single or combination treatments. Mechanistic study revealed that, besides inducing mitogen-activated protein kinase (MAPK)-related apoptosis, JB could trigger the paraptosis via activation of reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress and extracellular signal-regulated kinase (ERK) pathway. The excessive production of ROS could be induced by JB via inhibition of thioredoxin reductase 1 (TrxR1) and depletion of glutathione (GSH). Collectively, JB that targets thioredoxin and GSH systems to induce two distinct cell death modes may serve as a promising candidate in future anti-bladder cancer drug development., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Lung cancer remains the leading cause of cancer death worldwide. Late diagnosis, chemoresistance, and metastasis are the main reasons for the high mortality rate of lung cancer. Therefore, the development of other treatments is urgent. Cediranib (CED), a vascular endothelial growth factor receptor (VEGFR) kinase inhibitor, shows promising antitumour activities in various cancers including lung cancer. Here, we explored the effects and the underlying molecular mechanism of CED on non-small-cell lung cancer (NSCLC) cell line A549 cells in vitro. Our results show that CED could inhibit A549 cell proliferation and cloning formation. Meanwhile, G1 phase cell cycle arrest was also found, as featured by the increased proportion of G1 phase cells as well as the reduction of G1 phase relative proteins CDK4/cyclin D1 and CDK2/cyclin E. Moreover, the ratio of LC3-II/LC3-I was elevated significantly in CED-treated groups compared with the controls. Furthermore, the expression of p-Akt, p-P38, p-Erk1/2, and p-mTOR proteins was decreased obviously in the treatment groups. These results suggest that CED could induce apoptosis and G1 phase cell cycle arrest in A549 cells. Meanwhile, CED may induce autophagy through MAPK/Erk1/2 and Akt/mTOR signal pathway in A549 cells., Competing Interests: No potential conflict of interest was reported by the authors., (Copyright © 2021 Menghuan Guo et al.)

Cell can integrate the caspase family and mammalian target of rapamycin (mTOR) signaling in response to cellular stress triggered by environment. It is necessary here to elucidate the direct response and interaction mechanism between the two signaling pathways in regulating cell survival and determining cell fate under cellular stress. Members of the caspase family are crucial regulators of inflammation, endoplasmic reticulum stress response and apoptosis. mTOR signaling is known to mediate cell growth, nutrition and metabolism. For instance, over-nutrition can cause the hyperactivation of mTOR signaling, which is associated with diabetes. Nutrition deprivation can inhibit mTOR signaling via SH3 domain-binding protein 4. It is striking that Ras GTPase-activating protein 1 is found to mediate cell survival in a caspase-dependent manner against increasing cellular stress, which describes a new model of apoptosis. The components of mTOR signaling-raptor can be cleaved by caspases to control cell growth. In addition, mTOR is identified to coordinate the defense process of the immune system by suppressing the vitality of caspase-1 or regulating other interferon regulatory factors. The present review discusses the roles of the caspase family or mTOR pathway against cellular stress and generalizes their interplay mechanism in cell fate determination.

Cervical cancer is the second most common malignant tumour threatening women's health. In recent years, heavy-ion beam therapy is becoming a newly emerging therapeutic mean of cancer; however, radio-resistance and radiation-induced damage constitute the main obstacles for curative treatment of cervical cancer. Therefore, to identify the radiosensitizers is essential. Here, we investigated the effects of Wnt signalling pathway on the response of 12 C 6+ radiation in HeLa cells. XAV939, an inhibitor of Wnt signalling pathway, was added two hours before 12 C 6+ radiation. 12 C 6+ radiation inhibited the viability of HeLa cells in a time-dependent manner, and inhibiting Wnt signalling using XAV939 significantly intensified this stress. Meanwhile, 12 C 6+ radiation induced a significant increased cell apoptosis, G2/M phase arrest, and the number of γ-H2AX foci. Supplementation with XAV939 significantly increased the effects induced by 12 C 6+ radiation alone. Combining XAV939 with 12 C 6+ irradiation, the expression of apoptotic genes (p53, Bax, Bcl-2) was significantly increased, while the expression of Wnt-related genes (Wnt3a, Wnt5a, β-catenin, cyclin D1 and c-Myc) was significantly decreased. Overall, these findings suggested that blockage of the Wnt/β-catenin pathway effectively sensitizes HeLa cells to 12 C 6+ irradiation, and it may be a potential therapeutic approach in terms of increasing the clinical efficacy of 12 C 6+ beams.

The mitochondrial proteins involved in spermatogenic cells apoptosis in zebrafish after carbon ion radiation (CIR) were screened. The relative biological effectiveness (RBE) of CIR in zebrafish testes was investigated. Apoptosis of testicular cells was measured within 24 hr following 1 and 4 Gy CIR. Immunoblotting was used to assess the levels of mitochondrial apoptotic proteins in testes, and proliferative and apoptotic spermatogenic cells were detected by immunofluorescence after CIR. Label-free quantitative (LFQ) and parallel reaction monitoring-based target proteomics (PRM) were combined to screen and validate differential mitochondrial proteins in testes between 4 Gy and control groups at 24 hr after CIR. The RBE of CIR in zebrafish testes was 1.48 ± 0.04, and induction of apoptosis by CIR was higher than that of X-rays in testicular cells. Mitochondrial apoptotic pathways play a crucial role in spermatogenic cells apoptosis after CIR, with 60 differential mitochondrial proteins identified. Among 20 target proteins, 12 were significantly upregulated, 2 were significantly downregulated in the 4 Gy CIR group. The results of PRM were consistent with label-free analysis. This is the first study to screen the differential mitochondrial proteins and provide useful information to understand the underlying mechanisms of spermatogenic cell apoptosis in zebrafish following CIR., (© 2019 Wiley Periodicals, Inc.)

The study aims to analyze the phenolic compounds in Malus spp. and evaluate their antioxidant and pro-apoptotic effects in BGC-803 gastric cancer cells. The results showed that cyanidin-3-galactoside was the main polyphenol in Malus "Royalty" (MR), while catechin, epicatechin, and proanthocyanidin B1 and B2 contents were higher in Malus "Cinnabar" (MC) and Malus micromalus (MM) than in MR fruits. The total polyphenol content, total flavonoid content, and antioxidative properties of Malus spp. fruits followed an order of MR > MC > MM. Fruit extracts could inhibit BGC-803 cells growth and induce apoptosis, with IC 50 values of 0.47, 0.36, and 0.31 mg/ml for MR, MC, and MM, respectively. Furthermore, fruit extracts induced cell apoptosis through increasing Bcl-2 and Bcl-xl (pro-apoptosis) expression and inhibiting Bax and Bak (anti-apoptosis) expression, thereby accelerating cell apoptosis. Taken together, these results demonstrate that red fruits (i.e., MR and MC) were more effective against cancer cells than green fruits (i.e., MM). PRACTICAL APPLICATIONS: Fruits of Malus spp. are ≤5 cm in size, considerably smaller than apples. They are rich in various natural bioactive compounds that are often consumed as a dietary supplement or used as natural raw materials for function food. In the current study, it is comprehensively characterized profile and bioactivity of phenolic metabolites in Malus spp. fruits of different colors, and found that red fruits are more effective in reducing the free radicals and inducing cancer cells apoptosis than green fruits. These findings are valuable for food technologists and food manufacturers, especially those who produce crabapple supplement. The study investigated the molecular mechanism of how Malus spp. fruits exert anti-cancer functions. This lays a theoretical foundation for future research on developing anti-cancer function food and provides helpful guidance for fruit market management and fruit processing industry., (© 2019 Wiley Periodicals, Inc.)

Background: Withaferin A (WFA), an anticancer constituent of the plant Withania somnifera, inhibits tumor growth in association with apoptosis induction. However, the potential role of WFA in the cardiovascular system is little-studied and controversial.Methods and Results:Two different doses of WFA were tested to determine their cardioprotective effects in myocardial ischemia/reperfusion (MI/R) injury through evaluation of cardiofunction in wild-type and AMP-activated protein kinase domain negative (AMPK-DN) gentransgenic mice. Surprisingly, cardioprotective effects (improved cardiac function and reduced infarct size) were observed with low-dose WFA (1 mg/kg) delivery but not high-dose (5 mg/kg). Mechanistically, low-dose WFA attenuated myocardial apoptosis. It decreased MI/R-induced activation of caspase 9, the indicator of the intrinsic mitochondrial pathway, but not caspase 8. It also upregulated the level of AMP-activated protein kinase (AMPK) phosphorylation and increased the MI/R inhibited ratio of Bcl2/Bax. In AMPK-deficient mice, WFA did not ameliorate MI/R-induced cardiac dysfunction, attenuate infarct size, or restore the Bcl2/Bax (B-cell lymphoma2/Mcl-2-like protein 4) ratio., Conclusions: These results demonstrated for the first time that low-dose WFA is cardioprotective via upregulation of the anti-apoptotic mitochondrial pathway in an AMPK-dependent manner.

Withaferin A (WFA), a withanolide derived from medicinal plant Withania somnifera, possesses anti-tumorigenic and immunomodulatory activities against various cancer cells. However, the role of WFA in myocardial ischemia reperfusion (MI/R) injury remains unclear. In the present study, we determined whether WFA may regulate cardiac ischemia reperfusion injury and elucidate the underlying mechanisms. We demonstrated that WFA enhanced H9c2 cells survival ability against simulated ischemia/reperfusion (SI/R) or hydrogen peroxide (H 2 O 2 )-induced cell apoptosis. In addition, the enhanced oxidative stress induced by SI/R was inhibited by WFA. Among the multiple antioxidant molecules determined, antioxidants SOD2, SOD3, Prdx-1 was obviously upregulated by WFA. When Akt inhibitor IV was administrated, WFA's suppression effect on oxidative stress was obviously abolished. Additional experiments demonstrated that WFA successfully inhibited H 2 O 2 induced upregulation of SOD2, SOD3, and Prdx-1, ameliorated cardiomyocyte caspase-3 activity via an Akt dependent manner. Collectively, these results support the therapeutic potential of WFA against cardiac ischemia reperfusion injury and highlight the application of WFA in cardiovascular diseases holding great promise for the future., (Copyright © 2018 Elsevier Inc. All rights reserved.)

We used chronic restraint-induced stress (CRIS) and iron ionizing radiation (IR) to mimic human exposure to psychological stress (PS) and IR in a mouse model, and to investigate the relationship among endoplasmic reticulum stress (ERS), apoptosis and autophagy in testicular toxicity. Male Trp53 +/- C57BL/6N mice were restrained for 6 h/day for 28 consecutive days, and total body irradiation with 0.1 or 2 Gy iron ion beam was performed on the day 8. Histopathological observation showed severely damaged spermatogenic cells, increased apoptotic cells, caspase-3 activation and cytochrome c release, indicating that IR and CRIS+IR induced testicular cell apoptosis. Upregulation of GRP78 (78-kDa glucose-regulated protein) suggested that IR and CRIS+IR induced ERS in the testes, and further analysis showed that apoptosis was enhanced by ERS through activation of the PERK/eIF2α/ATF4/CHOP pathway. Decreased expression of LC3II, Atg5 (autophagy related 5) and Beclin 1, and increased expression of p62, combined with ultrastructural changes seen under transmission electron microscopy, suggest that IR and CRIS+IR inhibit autophagosome formation. This process was related to inhibition of autophagy via activation of the PI3K/AKT/mTOR pathway under ERS. We showed that apoptosis was strengthened and autophagy was inhibited by ERS in mouse testes induced by IR and CRIPS+IR. These results showed that CRIS+IR had no difference in apoptosis induction and autophagy inhibition compared with IR alone. CIRS alone could induce apoptosis only in Leydig cells and its induction of pathological and molecular changes in testicular tissues was only a small extent as compared to those induced by IR. Of note, we showed that 28 consecutive days of CRIS did not exacerbate IR effects (no additive effect with IR). These findings also suggest that studies on the concurrent exposure to PS and IR should be done using different endpoints in both short and long-term CRIS models., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Physalin B (PB), one of the major active steroidal constituents of Cape gooseberry (Physalis alkekengi L.), possesses a wide spectrum of biological activities. Although the anticancer activity of PB was reported in previous studies, the underlying mechanisms are still not well stated. In this study, the anticancer effect and the underlying mechanisms of PB were investigated in breast cancer cells. PB significantly reduced the viability of three human breast cancer cell lines, MCF-7, MDA-MB-231 and T-47D, in a concentration- and time-dependent manner. PB induced cell cycle arrest at G2/M phase and promoted cleavage of PARP (poly (ADP-ribose) polymerase), caspases 3, caspase 7 and caspase 9 to stimulate cell apoptosis. Further studies showed that PB induced breast cancer cells apoptosis in a p53-dependent manner in MCF-7 cells. PB also suppressed the phosphorylation of Akt (protein kinase B) and PI3K (phosphoinositide 3-kinase), and increased the phosphorylation of GSK-3β (glycogen synthase kinase 3β). Taken together, our results indicated that PB might serve as a potential therapeutic agent for breast cancer., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Endothelial cell damage, such as apoptosis and necrosis, is involved in many cardiovascular diseases. In recent years, the crucial role of microRNAs in controlling tissue homeostasis and disease in the epithelium has become widely recognized. In the present study, human umbilical vein endothelial cells were transfected with a miRNA agomir and a SMAD4 expression vector. The expression of miR125b-5p was determined by using quantitative real-time polymerase chain reaction. Cell apoptosis and necrosis were measured with flow cytometry. The expression of SMAD4 was evaluated with Western blotting. Here, we demonstrated that the rates of apoptosis and necrosis were significantly decreased in the miR125b-5p agomir group of HUVECs under H 2 O 2 -induced oxidative stress compared with the miR125b-5p antagomir group. Further experiments revealed that the expression of SMAD4 is negatively regulated by miR125b-5p. Moreover, we identified that the rates of apoptosis and necrosis were increased when SMAD4 and miR125b-5p were both overexpressed compared with miR125b-5p overexpression alone. The present study demonstrates for the first time that the overexpression of miR125b-5p can reduce H 2 O 2 -induced oxidative damage via SMAD4, suggesting that miR125b-5p has therapeutic potential for preventing oxidative stress-related diseases., (Copyright © 2017. Published by Elsevier Masson SAS.)

Objective To investigate the effect of lapatinib on cell proliferation and apoptosis in acute myeloid leukemia HL60 cells in vitro and the related molecular mechanisms. Methods The HL60 cells were treated with 5, 10, 15 μmol/L lapatinib for 24 hours, and then morphological changes of the cells were observed under optical microscope. CCK-8 assay was used to assess the cell viability. Colony formation assay was performed to detect the cell proliferation ability. Cell apoptosis labeled by annexinV-FITC/PI were analyzed by flow cytometry. Wright modified LIU's staining and Hoechst33342 fluorescent staining were used to observe the morphology of the nucleus. Western blotting was utilized to detect the expressions of Bax, Bcl2, caspase-3, caspase-9, cleaved caspase-3, cleaved caspase-9, cleaved poly-ADP-ribose polymerase (cleaved PARP), cell proliferation regulating inhibitor of protein phosphatase 2A (CIP2A), c-MYC, AKT and p-AKT. Results Compared with the control group, lapatinib inhibited cell proliferation and promoted apoptosis, induced nuclear fragmentation, chromatin condensation of HL60 cells in a dose-dependent manner. Meanwhile, it down-regulated the expression of Bcl2, up-regulated the levels of Bax, cleaved caspase-3, cleaved caspase-9 and cleaved PARP, and decreased the levels of CIP2A, p-AKT and c-MYC. Conclusion Lapatinib could inhibit cell proliferation and promote apoptosis in HL60 cells by inhibiting the CIP2A/AKT/c-MYC signal pathway.

Sirtuin 1 (Sirt1) promotes adaptive thermogenesis by controlling the acetylation status of enzymes and transcriptional factors in interscapular brown adipose tissue (iBAT). However, the effects of Sirt1 on endoplasmic reticulum (ER) stress and apoptosis of iBAT remain elusive. In this study, the mRNA levels of Sirt1 and thermogenesis genes were reduced but the genes related with ER stress were elevated in iBAT of high-fat diet (HFD)-induced obese mice. Moreover, ER stress further inhibited mRNA level of Sirt1 and triggered brown adipocyte apoptosis in vitro and in vivo. Further analysis revealed that Sirt1 overexpression alleviated ER stress-induced brown adipocyte apoptosis by inhibiting Smad3 and ATF4. In addition, Smad3 bound to ATF4 promoter region and positively transcriptional regulation of ATF4. Our data also confirmed that Sirt1 reduced early apoptotic cells and blocked the mitochondrial apoptosis pathway by directly interacting with ATF4. Furthermore, Sirt1 attenuated tunicamycin-induced cold intolerance and elevating thermogenesis by inhibiting ER stress and apoptosis in iBAT. In summary, our data collectively revealed Sirt1 reduced ER stress and apoptosis of brown adipocyte in vivo and in vitro by inhibiting Smad3/ATF4 signal. These data reveal a novel mechanism that links Sirt1 to brown adipocyte apoptosis.

Adiponectin is a cytokine produced predominantly by adipose tissue and correlates with glucose and lipid homeostasis. However, the effects of adiponectin on endoplasmic reticulum (ER) stress and apoptosis of adipose tissue remain elusive. In this study, we found that tunicamycin-induced ER stress increased serum free fatty acid (FFA) and impaired glucose tolerance, elevated the mRNA levels of GRP78, Chop, ATF2 and caspase 3, but reduced adiponectin mRNA level in white adipose tissue. Moreover, ER stress-triggered adipocyte apoptosis by increasing cellular FFA level and Ca 2+ level. Further analysis revealed that adiponectin alleviated ER stress-induced adipocyte apoptosis by elevating peroxisome proliferator-activated receptor alpha (PPARα) mRNA level. Our data also confirmed that adiponectin reduced early apoptotic cells and blocked the mitochondrial apoptosis pathway by activating the AdipoR1/AMP-activated protein kinase (AMPK) signal pathway. In addition, PPARα bound to ATF2 promoter region and inhibited transcription of ATF2. The inhibition of adipocyte apoptosis by adiponectin was correlated with transcriptional suppression of ATF2. Furthermore, adiponectin inhibited ER stress-induced apoptosis by activating the AMPK/PKC pathway. In summary, our data demonstrate adiponectin inhibited ER stress and apoptosis of adipocyte in vivo and in vitro by activating the AMPK/PPARα/ATF2 pathway. Our study establishes that adiponectin is an important adipocytokine for preventing and treating obesity.

The phenomenon has raised the concerns about the safety of an extended manned mission into deep space due to the high potential for exposure to high-LET radiation during space missions. Heavy ions such as (56)Fe are main radiation sources in deep space, which could pose a significant hazard to space flight crews during and after missions. Since the testis is a radiosensitive organ, which may be susceptible to space radiation-induced changes. In this study, we investigated the effect and potential mechanisms of (56)Fe irradiation on mouse testis. Pathological characteristics were measured following whole-body irradiation with 0.5 and 1Gy (56)Fe irradiation. Flow cytometry and terminal dUTP nick end-labeling (TUNEL) were performed to detect apoptotic cells. Western blot was applied to identify potential biomarkers. Immunofluorescence was used to investigate protein localization. We found that pathologic changes and apoptosis cells were significantly higher in 1Gy group than those in 0Gy groups. In addition, protein expression and localization studies confirmed Nrf2 was involved in this acute injury. Nrf2 and its target genes HO-1 and NQO1 were up-regulated in the irradiated testis in a dose-dependent manner. Nrf2 may be useful molecular markers in radiation-induced cellular responses and is important for detecting abnormal spermatogenesis following exposure to space radiation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Aims: Heavy ions have become potentially radiotherapeutic tools. However, studies of the effects on development of normal organs were limited. Using a zebrafish model, this study investigated the potential developmental toxicity and cell apoptosis rates in eyes exposed to carbon-ion irradiation., Main Methods: Zebrafish embryos at 12h post-fertilization (hpf) were irradiated using (12)C(6+) ion beams at doses of 2, 4, and 8 Gy. The reactive oxygen species (ROS) concentration was detected using the dichlorofluorescein-diacetate at 24, 48, and 72 hpf. Apoptosis was assessed by acridine orange staining at 24, 48, and 72 hpf and was also detected using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling assay, at 72 hpf. The expression of genes governing apoptosis was examined using real-time polymerase chain reaction at 24 hpf. Eye size was measured at 144 hpf., Key Findings: Ion irradiation with (12)C(6+) induced a significant increase in cell apoptosis at 24, 48 and 72 hpf. However, there was no significant increase in the ROS concentration at 24, 48, and 72 hpf. The proapoptotic genes, including P53, Bax, and Puma, were significantly upregulated. Two antiapoptotic genes, Mdm2 and Bcl-2, were significantly downregulated, and the expression levels of Capspase-9 and Caspase-3 were significantly increased. Microphthalmia was noted in the 8 Gy irradiated group., Significance: These results suggested that carbon-ion irradiation induced apoptosis through the p53 pathway in zebrafish eyes independent of ROS generation. Irradiation at high doses may disrupt eye development of zebrafish embryos., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Forkhead box C2 (Foxc2) protein is a transcription factor in regulation of development, metabolism, and immunology. However, the regulatory mechanisms of Foxc2 on proliferation and apoptosis of preadipocytes are unclear. In this study, we found that high-fat-diet-induced obesity elevated the expression of Foxc2 and cyclin E after 6 weeks. Additionally, Foxc2 suppressed preadipocyte differentiation, increased cell counts and augmented G1-S transition of preadipocytes, along with the elevation of cyclin E expression and the reduction levels of p27 and p53. Furthermore, Foxc2 knockdown reduced early apoptotic cells with accompanying reduction of mitochondrial membrane potential and increased fragmentation of genomic DNA. We show that Foxc2 reduces the expression of Bax, caspase-9, and caspase-3 in both serum-starved and palmitic acid-induced cell apoptotic models, which confirms the anti-apoptotic role of Foxc2. Moreover, the protein kinase B (Akt)/mammalian target of rapamycin (mTOR)C1 signaling pathway and the ERK/mTORC1 signaling pathway were activated along with preadipocyte proliferation in response to Foxc2 overexpression, whereas apoptosis marker genes were downregulated during this process. Those effects were blocked by the interference of Foxc2 or signal pathways specific inhibitors. These data collectively reveal that Foxc2 enhances proliferation of preadipocytes and inhibits apoptosis of preadipocytes by activating the Akt/mTORC1 and ERK/mTORC1 signaling pathways., (Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.)

The suppressor of cytokine signaling 3 (SOCS3) is an established negative feedback regulation transcription factor associated with leptin, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and growth hormone (GH). However, the regulatory mechanism of SOCS3 on inflammation and apoptosis of adipocyte is still not clear. In this study, we found an increased expression of adipocyte inflammatory cytokines TNF-α and IL-6 due to leptin treatment. Meanwhile Caspase3, a key executioner of apoptosis, was also elevated in this process. In addition, we observed that SOCS3 could promote inflammation whereas SOCS3 interference reversed this effect in LPS-induced adipocytes inflammatory model. Moreover, the expression of apoptosis-associated genes Bax, cleaved-Caspase9 and cleaved-Caspase3 were elevated along with decreased Bcl-2 expression as detected with Western blot and ELISA assay. The phosphorylation level of JAK2/STAT3 signal was inhibited by SOCS3 along with the elevated expression of IL-6, TNF-α and Caspase3. We also demonstrated that stable knockdown of SOCS3 along with SD1008, a specific inhibitor of JAK2/STAT3 signaling pathway, could significantly inhibit inflammation and apoptosis of adipocyte. Altogether, these results inferred that SOCS3 promotes adipocyte apoptosis by both aggravating inflammation and inhibiting the activity of JAK2/STAT3 signaling pathway., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Carbon-based materials have been widely used in the biomedical fields including drug delivery and cancer therapies. In this paper, a recently synthesized three-dimensional nanographene (NG) based on triptycene self-assembles into nanoparticles which selectively kill human hepatocellular carcinoma HepG2 cells as compared to human normal liver HL7702 cells. Obvious differences in cellular accumulation, the endocytic pathway and intracellular trafficking of NG nanoparticles are observed in HepG2 cells and HL7702 cells. Further studies reveal that NG nanoparticles significantly increase the levels of reactive oxygen species (ROS) in HepG2 cells, but not in HL7702 cells. NG nanoparticle-induced ROS result in apoptosis induction and the decrease in mitochondrial membrane potential in HepG2 cells. Moreover, IKK/nuclear factor-κB (NF-κB) signaling is found to be activated by NG nanoparticle-induced ROS and serves to antagonize NG nanoparticle-induced apoptosis in HepG2 cells. Our studies show that the distinct behaviors of cellular uptake and ROS-mediated cytotoxicity are responsible for the selective killing of HepG2 cells. This study provides a foundation for understanding the mechanism of selective induction of apoptosis in cancer cells by NG nanoparticles and designing more effective chemotherapeutical agents.

Diallyl disulfide (DADS), extracted from crushed garlic by steam-distillation, has been reported to provide the anticancer activity in several cancer types. However, the effect of DADS on high-LET carbon beams - induced cell death remains unknown. Therefore, we used human cervical cancer cells to elucidate the molecular effects of this diallyl sulfide. Radiotherapy remains the mainstay of treatment, especially in advanced cervical cancer and there is still space to improve the radiosensitivity to reduce radiation dosage. In this study, we found that radiation effects evoked by high-LET carbon beam was marked by inhibition of cell viability, cell cycle arrest, significant rise of apoptotic cells, regulation of transcription factor, such as p73, as well as alterations of crucial mediator of the apoptosis pathway. We further demonstrated that pretreatment of 10 µM DADS in HeLa cells exposed to radiation resulted in decrease in cell viability and increased radiosensitivity. Additionally, cells pretreated with DADS obviously inhibited the radiation-induced G2/M phase arrest, but promoted radiation-induced apoptosis. Moreover, combination DADS and the radiation exacerbated the activation of apoptosis pathways through up-regulated ration of pro-apoptotic Tap73 to anti-apoptotic ΔNp73, and its downstream proteins, such as FASLG, and APAF1. Taken together, these results suggest that DADS is a potential candidate as radio sensitive agent for cervical cancer.

Background Information: Microtubule affinity-regulating kinase 4 (MARK4) deficiency has been reported to negatively regulate diet-induced obesity and to mitigate insulin resistance in knockout mice, and thus may play a role in metabolic syndrome. However, the details of the molecular mechanism have yet to be revealed and the impacts of MARK4 on apoptosis remain unexplored. This study investigated the role of Mark4 in the regulation of lipid accumulation and apoptosis in adipocytes and analysed signalling pathways involved., Results: We found that Mark4 significantly up-regulated the expression of gene sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), acetyl-CoA carboxylase-α (ACCα) and peroxisome proliferator activated receptor-γ (PPARγ); and reduced the protein contents of adipose triglyceride lipase (ATGL), as evidenced by the dramatic increasing lipid droplet accumulation in 3T3-L1 cells. Furthermore, a terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) apoptosis assay showed that Mark4 triggered apoptosis of adipocytes; and apoptosis was confirmed by the decreased protein contents of B-cell lymphoma-2 (Bcl-2), full-length caspase-3 and full-length caspase-9, as well as the increased expression of Bax, cleaved caspase-3 and cleaved caspase-9. Analysis of special inhibitors allowed us to offer the following explanation for these impacts of Mark4: activation of Jun N-terminal kinase1 (JNK1) promoted both apoptosis and adipogenesis, whereas inhibition of the p38 mitogen-activated protein kinase (p38MAPK) pathway contributed to lipid accumulation alone., Conclusions: Mark4 promotes adipogenesis in 3T3-L1 adipocytes by activating the JNK1 and inhibiting the p38MAPK pathway, and triggers apoptosis by activating the JNK1 pathway. We conclude that anti-Mark4 therapy targetted to inhibit lipid accumulation and apoptosis of adipocytes shows potential as a novel therapeutic strategy for treatment of obesity-associated metabolic complications., (© 2014 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.)

Suppressor of cytokine signaling 3 (SOCS3), a signal transduction cytokine, is involved in lipid metabolism as well as in cell proliferation, differentiation, apoptosis, and so on. To explore the effects of SOCS3 on apoptosis and lipid metabolism in liver, we used a simple effective method named hydrodynamic tail vein injection to overexpress SOCS3. Then orbital blood was obtained for the assessment of blood lipid after injection. Lipid metabolism related genes were detected by Western blot after the determination of serum lipids. Meanwhile, liver cell apoptosis was observed by Hoechst and TUNEL staining and the expression of apoptosis related proteins Bax, Bcl-2, and Caspase3 were detected as well as the JAK2/STAT3 signaling pathway. In addition, we also demonstrated the effect of SOCS3 in prime hepatocyte by overexpression or interference of SOCS3 along with SD1008, which is a specific inhibitor of the JAK2/STAT3 signaling pathway. Taken together, all the results indicated that SOCS3 promoted lipid synthesis in mice liver and promoted hepatocyte apoptosis by inhibiting the activation of the JAK2/STAT3 signaling pathway, however the detailed regulation mechanism had not yet been fully understood and needs further study.

To examine the mechanisms by which licochalcone B (LCB) inhibits the proliferation of human malignant bladder cancer cell lines (T24 and EJ) in vitro and antitumor activity in vivo in MB49 (murine bladder cancer cell line) tumor model. Exposure of T24 or EJ cells to LCB significantly inhibited cell lines proliferation in a concentration-dependent and time-dependent manner, and resulted in S phase arrest in T24 or EJ cells, respectively. LCB treatment decreased the expression of cyclin A, cyclin-dependent kinase (CDK1 and CDK2) mRNA, cell division cycle 25 (Cdc25A and Cdc25B) protein. In addition, LCB treatment down-regulated Bcl-2 and survivin expression, enhanced Bax expression, activated caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) protein. Consistently, the tumorigenicity of LCB-treated MB49 cells was limited significantly by using the colony formation assay in vitro and the MB49 tumor model performed in C57BL/6 mice in vivo. These findings provide support for the use of LCB in chemoprevention and bladder cancer therapy., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

FATP1 plays an important role in the trafficking of free fatty acids in adipocytes, however, its precise function and relationship with other fatty acid transporters all remain poorly understood. In this study, FATP1 gene silencing was induced by transfecting siRNA of target sequence into chicken preadipocytes, then the expression of FABP was found down-regulated while the expression of FAT was raised. In addition, differential inhibition of the cells was observed and the expressions of PPARγ and C/EBPα were found down-regulated. Moreover, the silencing also induced the down-regulation of FAS and inhibited the adipogenesis in adipocytes. Of specific interest here was that FATP1 silencing significantly improved the expressions and activities of cell apoptotic factors Caspases 3 and BCL2 associated X protein (Bax). Consequently, FATP1 deficiency prevented the differentiation while induced apoptosis in chicken preadipocytes.

Objective: Isoliquiritigenin (ISL), a licorice chalconoid, is considered to be a bioactive agent with chemopreventive potential. This study investigates the mechanisms involved in ISL-induced apoptosis in human cervical carcinoma HeLa cells., Methods: Cell viability was evaluated using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay. Apoptosis was determined by flow cytometry using an Annexin V-FITC Apoptosis Detection Kit. The intracellular ROS levels were assessed using a 2, 7-dichlorofluorescein probe assay. The mitochondrial membrane potential was measured with the dual-emission potential-sensitive probe 5, 5', 6, 6'-tetra-chloro-1, 1', 3, 3'-tetraethyl-imidacarbocyanine iodide (JC-1). The degradation of poly-ADP-ribose polymerase (PARP) protein, the phosphorylation of PKR-like ER kinase (PERK), the phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α), the expression of the 78 kD glucose-regulated protein (GRP 78), and the activation of caspase-12 were analyzed via western blot analysis., Results: ISL significantly inhibited the proliferation, the increase in ROS levels and apoptotic rates of HeLa cells in a concentration-dependent manner. Moreover, ISL induced mitochondrial dysfunction, caspase activation, and PARP cleavage, which displayed features of mitochondria dependent on apoptotic signals. Besides, exposure of HeLa cells to ISL triggered endoplasmic reticulum (ER) stress, as indicated by the increase in p-eIF2α and GRP78 expression, ER stress-dependent apoptosis is caused by the activation of ER-specific caspase-12., Conclusion: The findings from our study suggest that ISL-induced oxidative stress causes HeLa cell apoptosis via the mitochondrion-dependent and the ER stress-triggered signaling pathways., (Copyright © 2013 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.)

Background: Dihydroartemisinin (DHA) exhibits potent anti-malarial and anti-cancer activities. This study aimed to investigate the anti-proliferative effects of a combination of DHA and doxorubicin (DOX) on human breast cancer cells., Methods: MTT assay and the combination index (CI) were used to show the anti-proliferative effects and calculate the synergism potential, respectively. Flow cytometry assay was used to detect apoptosis and the intracellular accumulation of DOX. JC-1 staining was used to determine the mitochondrial membrane potential. Western blot analysis was used to detect the protein expression of some apoptosis-related molecules., Results: Asynergistic anti-proliferative effect was found, and the enhanced anti-cancer activity was observed to be accompanied by the prompt onset of apoptosis in MCF-7 cells. The combinative treatment remarkably decreased the mitochondrial membrane potential and activated caspase cascades more than the mono-treatment. Pretreatment with DHA also did not influence the accumulation of DOX in MCF-7 cells., Conclusion: This study presented a new opportunity to enhance the effectiveness of future treatment regimens of breast cancer using DOX.

Ghrelin is a multifunctional peptide that actively protects against cardiovascular ischemic diseases, but the underlying mechanisms are unclear. We used CoCl(2) to mimic hypoxic conditions in cardiac H9c2 cells in order to study the mechanism by which ghrelin protects cardiac myocytes against hypoxic injury by regulating the content of intracellular ROS and autophagy levels. Cell apoptosis and necrosis were evaluated by the flow cytometry assay, Hoechst staining, and LDH activity. Cell viability was detected by the WST-1 assay; ROS levels were assessed using DCFH2-DA; and Nox1, catalase and Mn-SOD were assayed by real-time PCR and activity assays. LC3II was measured by Western blot analysis. We observed that CoCl(2) induced apoptosis and death of H9c2 cells in a dose- and time-dependent manner. This was characterized by an increase in cell apoptosis, LDH activity, ROS content, Nox1 expression, and autophagy levels and a decrease in cell viability, catalase, and Mn-SOD activities. Ghrelin treatment significantly attenuated CoCl(2)-induced hypoxic injury by decreasing cell apoptosis, LDH activity, ROS content, and Nox1 expression and increasing cell viability, autophagy levels, catalase, and Mn-SOD mRNA levels and activities. Further experiments revealed that inhibiting autophagy using 3-MA or AMPK pathway with compound C almost abrogated the induction of ghrelin in autophagy. This was associated with a decrease in cell viability and an increase in LDH activity. Our results indicate that ghrelin protected cardiac myocytes against CoCl(2)-induced hypoxic injury by decreasing Nox1 expression, increasing the expression and activity of endogenous antioxidant enzymes, and inducing protective autophagy in an AMPK-dependent manner., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Taxane chemotherapy is one of the few therapeutic options for men with castration-resistant prostate cancer. However, the working mechanisms are not fully understood. We aimed to investigate the possible molecular mechanism of apoptosis induced by taxanes in prostate cancer., Methods: The human LNCaP cells (bearing wild-type p53), DU145 cells (bearing mutant p53) and PC3 cells (lacking p53) were used. The expression levels of protein were determined by Western blot and the mRNA levels were determined by reverse transcriptase PCR. The apoptosis was measured by propidium iodide (PI) staining and flow cytometric analysis., Results: LNCaP cells are more resistant to docetaxel than DU145 and PC3 cells. Knocking down p53 by small interference RNA (siRNA) sensitizes LNCaP cells to docetaxel treatment. Docetaxel stabilizes p53 protein level and upregulates p21 in a p53-dependent manner in LNCaP cells. Docetaxel increases p38 phosphorylation in LNCaP cells. Treatment with p38-specific inhibitor SB203580 or knocking down p38 by siRNA significantly impaired the upregulation of p53 and p21 by docetaxel. Knocking down p38 or p21 sensitizes LNCaP cells to docetaxel treatment and the antiapoptotic effect of p21 can be reversed by p38 siRNA in LNCaP cells., Conclusions: Stimulation of the p38/p53/p21 signaling axis could be important for regulating the susceptibility towards docetaxel in prostate cancer., (Copyright © 2011 Wiley-Liss, Inc.)

Apoptosis is a pivotal process in embryogenesis and postnatal cell homeostasis and involves the shedding of membranous microvesicles termed apoptotic bodies. In response to tissue damage, the CXC chemokine CXCL12 and its receptor CXCR4 counteract apoptosis and recruit progenitor cells. Here, we show that endothelial cell-derived apoptotic bodies are generated during atherosclerosis and convey paracrine alarm signals to recipient vascular cells that trigger the production of CXCL12. CXCL12 production was mediated by microRNA-126 (miR-126), which was enriched in apoptotic bodies and repressed the function of regulator of G protein (heterotrimeric guanosine triphosphate-binding protein) signaling 16, an inhibitor of G protein-coupled receptor (GPCR) signaling. This enabled CXCR4, a GPCR, to trigger an autoregulatory feedback loop that increased the production of CXCL12. Administration of apoptotic bodies or miR-126 limited atherosclerosis, promoted the incorporation of Sca-1+ progenitor cells, and conferred features of plaque stability on different mouse models of atherosclerosis. This study highlights functions of microRNAs in health and disease that may extend to the recruitment of progenitor cells during other forms of tissue repair or homeostasis.

Background: During the process of metastasis, cells are subjected to various apoptotic stimuli. Aberrant expression of apoptotic regulators often contribute to cell metastasis. Heat shock protein 27(HSP27) is confirmed as an apoptosis regulator, but its antiapoptotic mechanism in metastatic hepatocellular carcinoma (HCC) cells remains unclear., Methods: Levels of HSP27 protein and its phosphorylation in Hep3B, MHCC97L to MHCC97H cells with different metastatic potentials were determined by western blot analysis. MHCC97H cells were transfected with specific small interference RNA (siRNA) against HSP27. The in vitro migration and invasion potentials of cells were evaluated by Transwell assay. The apoptosis ratio of MHCC97H cells was analyzed by TUNEL staining and Flow Cytometry. Alteration of signal transduction pathway after HSP27 knockdown in MHCC97H cells was evaluated through a Human Q Series Signal Transduction in Cancer Gene Array analysis. Nuclear NF-kappaB contentration and endogenous IKK activity were demonstrated by ELISA assay. The association of IKKalpha, IKKbeta, IkappaBalpha with HSP27 and the association between IKKbeta and IKKalpha in MHCC97H cells were determined by co-immunoprecipitation assay followed by western blot analysis., Results: HSP27 protein and its phosphorylation increased in parallel with enhanced metastatic potentials of HCC cells. siRNA-mediated HSP27 knockdown in MHCC97H significantly suppressed cells migration and invasion in vitro and induced cell apoptosis; the prominently altered signal transduction pathway was NF-kappaB pathway after HSP27 knockdown in MHCC97H cells. Furthermore, inhibition of HSP27 expression led to a significant decrease of nuclear NF-kappaB contentration and endogenous IKK activity. In addition, HSP27 was associated with IKKalpha, IKKbeta, IkappaBalpha in three HCC cells above. ELISA assay and western blot analysis also showed a decrease of the association between IKKbeta and IKKalpha, the association between phosphor-HSP27 and IKK complex, and an increase of total IkappaBalpha but reducing tendency of phosphor-IkappaBalpha when HSP27 expression was efficiently knocked down in MHCC97H cells., Conclusion: Altogether, these findings revealed a possible effect of HSP27 on apoptosis in metastatic HCC cells, in which HSP27 may regulate NF-kB pathway activation.

Aim: To investigate the pro-apoptotic effects of alpha1-adrenergic inhibitor doxazosin in HeLa cells and the potential involvement of transcription factor activator protein-2alpha (AP-2alpha) in doxazosin-induced apoptosis., Methods: The HeLa cells were exposed to various concentrations of doxazosin for 16 h. Apoptosis was detected using a DNA fragmentation assay, Hoechst 33258 staining, and flow cytometric analysis. The expression of AP-2alpha and caspase-3 was detected by relative quantitative RT-PCR and Western blot assays, respectively. After the respective transfections of the HeLa cells with AP-2alpha overexpressing constructs and an antisense oligonucleotide against AP-2alpha, apoptosis was assessed by flow cytometric analysis, and the expression of AP-2alpha and caspase-3 was detected by relative quantitative RT-PCR and Western blot assays. The colorimetric assay was performed to detect the caspase-3 activity., Results: Treatment with various concentrations of doxazosin for 16 h increased the apoptotic rate and total cell death rate of the HeLa cells in a dose-dependent manner and upregulated the expression of AP-2alpha and caspase-3 in a dose-dependent manner. A dose-dependent increase was observed in the caspase-3 activity. Overexpressing AP-2alpha led to the increased rate of doxazosin-induced apoptosis and the total cell death, whereas doxazosin-induced apoptosis and the total cell death in HeLa cells decreased by antisense AP-2alpha. Furthermore, overexpressing AP-2alpha increased the expression and activity of caspase-3, whereas antisense AP-2alpha in part abolished the increased effects of doxazosin on caspase-3 expression and activity., Conclusion: Doxazosin induces apoptosis in HeLa cells in a dose-dependent manner, and transcription factor AP-2alpha is functionally involved in doxazosin-induced HeLa cell apoptosis.

Objective: To investigate the efficacy of inducing apoptosis in human bladder cancer cells by adriamycin and mitomycin and relevant mechanism., Methods: Human bladder cancer cells of the lines RT4, MGH-U1, FJ, and T24 were cultured. Adriamycin of the concentrations of 0.1, 1, and 10 microg/ml, and mitomycin of the concentrations of 0.01, 0.1, and 1 microg/ml were added into the culture fluid respectively. CCK-8 colorimetric assay was used to detect the survival rates of the cells so as to select the cell line sensitive and tolerable to the drugs. Flow cytometry was used to detect the cell apoptosis. Western blotting was used to detect the levels of X-kinked inhibitor of apoptosis protein (XIAP) and the cleavage of caspase-3 precursor., Results: It was found that RT4 cells were the most sensitive and the T24 cells were the most tolerable to adriamycin and mitomycin. Treated with adriamycin of the concentrations of 0.1, 1, and 10 microg/ml for 24 hours, the apoptotic rates of the RT4 cells were 15.3% +/- 4.3%, 29.3% +/- 6.4%, and 45.0% +/- 5.5% respectively; and the apoptotic rates of the T24 cells were 7.3% +/- 3.1%, 12.5% +/- 4.3%, and 18.2% +/- 6.3% respectively, all significantly lower than those of the RT4 cells (P < 0.05 or P < 0.01). Treated with mitomycin of the concentrations of 0.01, 0.1, and 1 microg/ml for 24 hours, the apoptotic rates of the RT4 cells were 12.7% +/- 2.9%, 31.3% +/- 4.4%, and 48.9% +/- 5.8% respectively, and the apoptotic rates of the RT4 cells were 7.2% +/- 3.3%, 15.5% +/- 5.2%, and 21.2% +/- 4.4% respectively, all significantly lower than those of the RT4 cells (all P < 0.05). The XIAP expression was not significantly different in these 4 cell lines before the adriamycin and mitomycin treatment. After the treatment of adriamycin and mitomycin, the expression of XIAP was down-regulated dose-dependently, however, being weaker in the T24 cells than in the RT4 cells; and caspase-3 precursor cleavage was enhanced, however, being weaker in the T24 cells too., Conclusion: Adriamycin and mitomycin dose-dependently kill the human bladder cancer cells. Such cytotoxic effect may be realized through inducing the cell apoptosis which is associated with the down-regulation of XIAP and cleavage of caspase-3 precursor.

Sulfated polymannuroguluronate (SPMG) has entered the phase II clinical trial as the first anti-AIDS drug candidate in China. Herein, we report that SPMG was effective at protecting T lymphocytes against apoptosis. Further studies indicated that SPMG significantly elevated mitochondrial membrane potential (MMP) of T cells; inhibited mitochondrial release of cytochrome c (cyto c) in T cells; enhanced the activities of mitochondrial enzyme complex I, III, and V; and subsequently increased ATP level and ATP/ADP ratio. In addition, SPMG potently suppressed reactive oxygen species (ROS) generation in mitochondria at cellular level and scavenged free radicals in cell-free system. The molecular mechanism underlying the ATP-involved and ROS-dependent antiapoptosis of SPMG is characterized as having been caused by its engagement with mitochondrial import receptor and ADP/ATP carrier in T-cell outer and inner mitochondrial membrane, respectively. All these might shed new light on the understanding of anti-AIDS functions of SPMG by protecting T cells of persons infected with human immunodeficiency virus.

Previous studies have demonstrated that realgar nanoparticles might provide a less toxic agent for antineoplasia by suppressing angiogenesis. Here, we addressed the question of whether the size effects on apoptosis induction mainly contribute to the comparably higher concentration of easily soluble As2O3 present in realgar nanoparticles. Results revealed that treatment with realgar nanoparticles resulted in considerably low cell viability and produced characteristic apoptotic events in HL-60 cells, including morphological changes, DNA ladder formation, and increased number of cells with sub-G1-phase, whereas raw realgar particles with the same As2O3 concentration failed to induce apoptosis. On the other hand, the effects of realgar nanoparticles and raw realgar particles on cell membrane were examined. Realgar nanoparticles had acute toxicity to cell membrane, potentiating lipid peroxidation, increasing lactate dehydrogenase (LDH) release, and reducing membrane fluidity, whereas raw realgar particles had little effect on cell membrane besides a similar reduction of membrane fluidity. These results suggest that the promotion of lipid peroxidation and membrane permeability might play an important role in the process of apoptotic induction by realgar nanoparticles. However, raw realgar particles are not sufficient to elicit apoptosis, although they can reduce membrane fluidity in HL-60 cells.

The effect and the mechanism of Lycium barbarum polysaccharide (LBP-X) on inhibiting the growth of human leukemia HL-60 cells were examined. LBP-X(20, 100, 500, 1000 mg/L) could inhibit the growth of HL-60 cells in dose-dependent manner and decrease the membrane fluidity of the cell. Agarose gel electrophoresis of DNA from the cells treated with LBP-X revealed a "DNA ladder" and positive TUNEL test. The results showed that the apoptosis of HL-60 cells induced by LBP-X maybe its important mechanism on anti-tumorgenesis.

Huntington disease is a devastating neurodegenerative disease caused by the expansion of a polymorphic glutamine tract in huntingtin. The huntingtin interacting protein (HIP-1) was identified by its altered interaction with mutant huntingtin. However, the function of HIP-1 was not known. In this study, we identify HIP-1 as a proapoptotic protein. Overexpression of HIP-1 resulted in rapid caspase 3-dependent cell death. Bioinformatics analyses identified a novel domain in HIP-1 with homology to death effector domains (DEDs) present in proteins involved in apoptosis. Expression of the HIP-1 DED alone resulted in cell death indistinguishable from HIP-1, indicating that the DED is responsible for HIP-1 toxicity. Furthermore, substitution of a conserved hydrophobic phenylalanine residue within the HIP-1 DED at position 398 eliminated HIP-1 toxicity entirely. HIP-1 activity was found to be independent of the DED-containing caspase 8 but was significantly inhibited by the antiapoptotic protein Bcl-x(L), implicating the intrinsic pathway of apoptosis in HIP-1-induced cell death. Co-expression of a normal huntingtin fragment capable of binding HIP-1 significantly reduced cell death. Our data identify HIP-1 as a novel proapoptotic mediator and suggest that HIP-1 may be a molecular accomplice in the pathogenesis of Huntington disease.

Purpose: Apoptosis was studied in rabbit corneas as a possible mechanism of cell death after photokeratitis induced by different UV wavelengths., Method: Fourteen albino rabbit corneas were exposed to 280- and 310-nm UV radiation (UVR) in 10-nm full wavebands at doses that cause biomicroscopically significant keratitis (0.12 J/cm2 for 280 nm and 0.47 J/cm2 for 310 nm). Animals were killed 24 and 76 h after exposure. Corneas were processed for light and transmission electron microscopy and in situ end labeling of fragmented DNA by using a modification of the TUNEL technique., Results: Corneas exposed to 280-nm UVR showed TUNEL-positive staining only in epithelial cells and superficial keratocytes at 24 and 76 h after irradiation. Twenty-four hours after 310-nm UVR exposure, TUNEL-positive staining was present in the epithelial cells, keratocytes throughout the entire thickness of the central stroma, and in endothelial cells. Seventy-six hours after exposure to 310-nm UVR, keratocytes disappeared throughout the whole thickness of the damaged stroma. Only a few epithelial cells were TUNEL positive at that time. Transmission electron microscopy (TEM) verified the occurrence of apoptotic nuclei and cells., Conclusion: Apoptosis appears to be a mechanism of corneal cell death after UVR. The 310-nm UVR caused more extensive damage to the corneal stroma and endothelium than did the 280-nm UVR.

Amyloid precursor proteins (APPs) are expressed in multiple organs and cell types in diverse species. Their conservation across species and high abundance in brain and the association of various APP missense mutations with autosomal dominant forms of familial Alzheimer's disease (FAD) suggest important roles for APP in the central nervous system. However, the basic functions of APP in the central nervous system remain largely unknown. To assess potential effects of APP on neuronal death and survival, we transfected APP-deficient rat neuroblastoma cells (B103) with DNA constructs encoding wild-type or FAD-mutant human APP. Wild-type, but not FAD-mutant, APP effectively protected cells against apoptosis induced by ultraviolet irradiation, staurosporine, or p53. Wild-type APP also strongly inhibited p53 DNA-binding activity and p53-mediated gene transactivation, whereas FAD-mutant APP did not. We conclude that APP protects neuronal cells against apoptosis by controlling p53 activation at the post-translational level. Disruption of this function by mutations or alterations in APP processing could enhance neuronal vulnerability to secondary insults and contribute to neuronal degeneration.

Purpose: To investigate DNA damage in the rat lens after in vivo close-to-threshold exposure to ultraviolet radiation (UVR)., Methods: Sprague-Dawley rats received 5 kJ/m2 UVR (lambdaMAX = 300 nm, lambda0.5 = 10 nm) unilaterally for 15 minutes. Animals were killed at 1, 6, and 24 hours and at 1 week after exposure. DNA-strand breaks were investigated in sagittal paraffin sections using the TdT-dUTP terminal nick-end labeling (TUNEL) technique and propidium iodide for counterstaining. Other lenses were prepared for transmission electron microscopy (TEM)., Results: TUNEL-positive nuclei were found at only 24 hours after UVR exposure. About one tenth of the epithelial cell nuclei were TUNEL positive, and affected cells were scattered over the entire epithelium. No TUNEL-positive cells were found at 1 or 6 hours or at 1 week after UVR exposure or in the nonexposed lenses. TEM verified the occurrence of programmed cell death and showed the breakdown of the apoptotic cells by adjacent cells. No signs of necrosis were found., Conclusions: Threshold-dose UVR induces programmed cell death that peaks 24 hours after exposure and involves the entire epithelium. Dead cells are removed from the epithelium by phagocytosis.

A cosmid clone containing the chicken T-cell receptor alpha chain constant region (TCRAC) was sequenced. The cosmid contains the TCRAC gene, six putative joining gene segments (TCRAJ), and surprisingly, a chicken homologue for the human apoptotic suppressor gene, defender against cell death (DAD1). The DAD1 gene is 6.3 kilobases downstream of the TCRAC gene and has an inverted transcription orientation with respect to the TCRAC gene. The cDNA for the chicken DAD1 gene is 597 base pairs in length and encodes a highly conserved hydrophobic protein. The proximal location of DAD1 to the TCRAC locus has also been confirmed in both humans and mouse. The location of the DAD1 gene suggests that DAD1 may play an important role in T-cell related apoptotic activities.

The toxic effects of x-ray radiation on eye development was measured using zebrafish as a model organism. Zebrafish embryos at 8 h post-fertilization (hpf) were irradiated using X-rays at doses of 1, 2, 4, and 8 Gy. At 24 and 48 hpf, x-ray radiation induced a significant increase in reactive oxygen species (ROS) content and cell apoptotic signals. Both of these increases were dose dependent and there were significant positive relationships between them at 24 hpf. At 48 and 72 hpf, the increase of ROS concentration can be eliminated by increasing activities of superoxide dismutase and catalase. Although the ROS generated by x-ray radiation caused a significant increase in cell apoptosis at 24 and 48 hpf, the cellular layers of the retina and lens formation in the irradiated groups were not significantly disrupted at 144 hpf compared with the control group, with the exception of a heterogeneous distribution of the cells in inner nuclear cell layer and a significant decrease in the diameters of whole eyes after 8 Gy irradiation. X-Ray radiation at later stages of gastrulation may not cause distinct optic complications; however, there is still a risk of microophthalmia at high doses of irradiation. [ABSTRACT FROM AUTHOR]