PM2.5 induce neurotoxicity via iron overload and redox imbalance mediated-ferroptosis in HT22 cells.

PM2.5 is an important risk factor for the development and progression of cognitive impairment-related diseases. Ferroptosis, a new form of cell death driven by iron overload and lipid peroxidation, is proposed to have significant implications. To verify the possible role of ferroptosis in PM2.5-induced neurotoxicity, we investigated the cytotoxicity, intracellular iron content, iron metabolism-related genes, oxidative stress indices and indicators involving in Nrf2 and ferroptosis signaling pathways. Neurotoxicity biomarkers as well as the ferroptotic cell morphological changes were determined by Western Blot and TEM analysis. Our results revealed that PM2.5 induced cytotoxicity, lipid peroxidation, as indicated by MDA content, and neurotoxicity via Aß deposition in a dose-related manner. Decreased cell viability and excessive iron accumulation in HT-22 cells can be partially blocked by ferroptosis inhibitors. Interestingly, GPX activity, Nrf2, and its regulated ferroptotic-related proteins (i.e. GPX4 and HO-1) were significantly up-regulated by PM2.5. Moreover, gene expression of DMT1, TfR1, IRP2 and FPN1 involved in iron homeostasis and NCOA4-dependent ferritinophagy were activated after PM2.5 exposure. The results demonstrated that PM2.5 triggered ferritinophagy-dependent ferroptotic cell death due to iron overload and redox imbalance. Activation of Nrf2 signaling pathways may confer a protective mechanism for PM2.5-induced oxidative stress and ferroptosis.

Repeated radon exposure induced epithelial-mesenchymal transition-like transformation via disruption of p53-dependent mitochondrial function.

Backgrouds: As a human carcinogen, radon and its progeny are the second most important risk factor for lung cancer after smoking. The tumor suppressor gene, p53, is reported to play an important role in the maintenance of mitochondrial function. In this work, we investigated the association between p53 and p53-responsive signaling pathways and radon-induced carcinogenesis. Methods: After repeated radon exposure, the malignant characteristics, cell cycle arrest, cell apoptotic rate, adenosine triphosphate (ATP) content, reactive oxygen species (ROS) level, mitochondrial DNA (mtDNA) copy number as well as indicative biomarkers involved in mitochondrial energy metabolism were evaluated in BEAS-2B cells or BALB-c mouse lung tissue. Results: Radon exposure induced epithelial-mesenchymal transition (EMT)-like transformation in BEAS-2B cells, as indicated by increased cell proliferation and migration. Additional mitochondrial alterations, including decreased ATP content, increased ROS levels, mtDNA copy numbers, cell apoptosis, and G2/M cell cycle arrest were observed. Radon exposure caused an energy generation shift from aerobic respiration to glycolysis as reflected by increased expression of TIGAR and p53R2 proteins and decreased expression of SCO2 protein in BEAS-2B cells, and increased expression of p53, SCO2 and TIGAR proteins in mouse lung tissue, respectively. The effects of p53 deficiency on the prevention of mitochondrial dysfunction suggested a protective role of p53 in radon-induced malignant-like features in BEAS-2B cells. Conclusions: Repeated radon exposure induced EMT-like transformation in BEAS-2B cells via disruption of mitochondrial function. Activation of p53 and p53-responsive signaling pathways in BEAS-2B cells and BALB-c mice may confer a protective mechanism for radon-induced lung injury.

Protection of melatonin against long-term radon exposure-caused lung injury.

Radon is one of the major pathogenic factors worldwide. Recently, epidemiological studies have suggested that radon exposure plays an important role in lung injury, which could further cause cancer. However, the toxic effects and underlying mechanism on lung injury are still not clear. Here, we identified the detailed toxic effects of long-term radon exposure. Specifically, the manifestations were inflammatory response and cell apoptosis in dose- and time-dependent manners. In detail, it caused the mitochondrial dysfunction and oxidative stress as determined by the abnormal levels of mitochondrial DNA copy number, adenosine triphosphate, mitochondrial membrane potential, superoxide dismutase, and cycloxygenase-2. Furthermore, we found that melatonin treatment ameliorated mitochondrial dysfunction and attenuated the levels of oxidative stress caused by long-term radon exposure, which could further inhibit the lung tissue apoptosis as determined by the decreased levels of cleaved caspase 3. Our study would provide potential therapeutic application of melatonin on lung tissue injury caused by long-term radon exposure.

1α,25(OH)2D3 Radiosensitizes Cancer Cells by Activating the NADPH/ROS Pathway.

The radioresistance of tumors affect the outcome of radiotherapy. Accumulating data suggest that 1α,25(OH)2D3 is a potential anti-oncogenic molecule in various cancers. In the present study, we investigated the radiosensitive effects and underlying mechanisms of 1α,25(OH)2D3 in vitro and in vivo. We found that 1α,25(OH)2D3 enhanced the radiosensitivity of lung cancer and ovarian cancer cells by promoting the NADPH oxidase-ROS-apoptosis axis. Compared to the group that only received radiation, the survival fraction and self-renewal capacity of cancer cells treated with a combination of 1α,25(OH)2D3 and radiation were decreased. Both apoptosis and ROS were significantly increased in the combination group compared with the radiation only group. Moreover, N-acetyl-L-cysteine, a scavenger of intracellular ROS, reversed the apoptosis and ROS induced by 1α,25(OH)2D3, indicating that 1α,25(OH)2D3 enhanced the radiosensitivity of cancer cells in vitro by promoting ROS-induced apoptosis. Moreover, our results demonstrated that 1α,25(OH)2D3 promoted the ROS level via activating NADPH oxidase complexes, NOX4, p22phox, and p47phox. In addition, knockdown of the vitamin D receptor (VDR) abolished the radiosensitization of 1α,25(OH)2D3, which confirmed that 1α,25(OH)2D3 radiosensitized tumor cells that depend on VDR. Similarly, our study also evidenced that vitamin D3 enhanced the radiosensitivity of cancer cells in vivo and extended the overall survival of mice with tumors. In summary, these results demonstrate that 1α,25(OH)2D3 enhances the radiosensitivity depending on VDR and activates the NADPH oxidase-ROS-apoptosis axis. Our findings suggest that 1α,25(OH)2D3 in combination with radiation enhances lung and ovarian cell radiosensitivity, potentially providing a novel combination therapeutic strategy.

Evaluation of the biomedical properties of a Ca+-conjugated silk fibroin porous material.

Hemostatic materials could reduce avertible death from bleeding during surgery and emergency treatment. To this end, silk fibroin (SF) loaded with Ca2+ (1.8, 3.6 5.4, or 7.2%, w:w) was tested as a new hemostatic material (designated as SF1.8, SF3.6, SF5.4, or SF7.2), and the Ca2+ release rate, platelet adhesion, blood coagulation, cytocompatibility, and antimicrobial properties were investigated. Platelet adhesion on SF1.8 was improved significantly compared with pure SF porous material, and increased with increasing Ca2+ concentration. For SF3.6, platelet adhesion was greater than observed for gelatin and calcium alginate porous materials, clotting occurred earlier, and the complete coagulation time was shorter. Additionally, rabbit ear wound studies revealed that the hemostatic time for SF3.6 was significantly shorter than for gelatin, and similar to that for calcium alginate. The shed blood weight was lowest when SF was loaded with 7.2% Ca2+. The SF3.6 porous material displayed no obvious cytotoxicity, and exhibited satisfactory antibacterial activity against Escherichia coli and Staphylococcus aureus.

Radon induced mitochondrial dysfunction in human bronchial epithelial cells and epithelial-mesenchymal transition with long-term exposure.

Radon is a naturally occurring radionuclide, which has a wide environmental distributed. It emits multiple high linear energy transfer (LET) alpha particles during radiative decay, and has been regarded as a human carcinogen by the International Agency for Research on Cancer. Currently, residential radon exposure is considered as the second highest cause of lung cancer and the leading cause among nonsmokers. Radon exposure leads to genomic instability, which causes the accumulation of multiple genetic changes and leads to cancer development. However, the molecular basis underlying carcinogenesis, especially the radon-induced changes to mitochondria, has not been fully elucidated. The aim of this study was to explore the dynamic changes in mitochondria along with the cell transformations induced by long-term radon exposure. A malignant transformation model of BEAS-2B cells was established with upto 40 times the usual radon exposure (20 000 Bq m-3, 30 min each time every 3 days). Long-term radon exposure induced EMT-like transformation of epithelial cells in our study, evidenced by decrease in epithelial markers and increase in mesenchymal markers, as well as the loss of cell-cell adhesion and alterations to the morphology of cells from compact shape to a spindle shaped, fibroblast-like morphology. Additionally, the proliferation and migration of cells were increased and apoptosis was decreased with long-term radon exposure. Furthermore, mitochondrial function was up-regulated and the levels of oxidative stress were repressed with long-term radon exposure. Our work explored the dynamic changes of mitochondrial in radon induced malignant transformation of lung bronchial epithelial cells, which could partially elucidate the role of mitochondria in radon induced cell malignancy.

Long Noncoding RNA CRYBG3 Blocks Cytokinesis by Directly Binding G-Actin.

The dynamic interchange between monomeric globular actin (G-actin) and polymeric filamentous actin filaments (F-actin) is fundamental and essential to many cellular processes, including cytokinesis and maintenance of genomic stability. Here, we report that the long noncoding RNA LNC CRYBG3 directly binds G-actin to inhibit its polymerization and formation of contractile rings, resulting in M-phase cell arrest. Knockdown of LNC CRYBG3 in tumor cells enhanced their malignant phenotypes. Nucleotide sequence 228-237 of the full-length LNC CRYBG3 and the ser14 domain of ß-actin is essential for their interaction, and mutation of either of these sites abrogated binding of LNC CRYBG3 to G-actin. Binding of LNC CRYBG3 to G-actin blocked nuclear localization of MAL, which consequently kept serum response factor (SRF) away from the promoter region of several immediate early genes, including JUNB and Arp3, which are necessary for cellular proliferation, tumor growth, adhesion, movement, and metastasis. These findings reveal a novel lncRNA-actin-MAL-SRF pathway and highlight LNC CRYBG3 as a means to block cytokinesis and to treat cancer by targeting the actin cytoskeleton.Significance: Identification of the long noncoding RNA LNC CRYBG3 as a mediator of microfilament disorganization marks it as a novel therapeutic antitumor strategy. Cancer Res; 78(16); 4563-72. ©2018 AACR.

Radon-induced reduced apoptosis in human bronchial epithelial cells with knockdown of mitochondria DNA.

Radon and radon progeny inhalation exposure are recognized to induce lung cancer. To explore the role of mitochondria in radon-induced carcinogenesis in humans, an in vitro partially depleted mitochondrial DNA (mtDNA) cell line (ρ-) was generated by treatment of human bronchial epithelial (HBE) cells (ρ+) with ethidium bromide (EB). The characterization of ρ- cells indicated the presence of dysfunctional mitochondria and might thus serve a reliable model to investigate the role of mitochondria. In a gas inhalation chamber, ρ- and ρ+ cells were exposed to radon gas produced by a radium source. Results showed that apoptosis was significantly increased both in ρ- and ρ+ cells irradiated by radon. Moreover, apoptosis in ρ- cells showed a lower level than in ρ+ cells. Radon was further found to depress mitochondrial membrane potential (MMP) of HBE cells with knockdown mtDNA. Production of reactive oxygen species (ROS) was markedly elevated both in ρ- and ρ+ cells exposed to radon. The distribution of phases of cell cycle was different in ρ- compared to ρ+ cells. Radon irradiation induced a rise in G2/M and decrease in S phase in ρ+ cells. In ρ- cells, G1, G2/M, and S populations remained similar to cells exposed to radon. In conclusion, radon-induced changes in ROS generation, MMP and cell cycle are all attributed to reduction of apoptosis, which may trigger and promote cell transformation, leading to carcinogenesis. Our study indicates that the use of the ρ- knockdown mtDNA HBE cells may serve as a reliable model to study the role played by mitochondria in carcinogenic diseases.

[Analysis of immunophenotype characteristics in 109 cases of B lineage chronic B lymphoid leukemia].

This study was aimed to investigate the immunophenotypic characteristics of 109 cases of B-cell chronic lymphoid leukemia (B-CLL) so as to provide evidences for the diagnosis and therapy of B-CLL, and for the detection of the minimal residual disease and its prognosis. Immunophenotyping was performed in 109 patients of B-CLL by two/three color multiparameter flow cytometry analysis using a panel of monoclonal antibodies. The results showed that in 109 cases of B-CLL, all cases expressed CD19, the positive ratios of other B lineage antigen such as CD20, CD22 and CD23 were 95.40%, 94.50%, 86.20% respectively. None of the B-CLL cases expressed CD10. The expression ratio of FMC-7 and CD38 in 105 cases of B-CLL were 28.60% and 36.20%. Among the B-CLL cases the CD5(+) cells amounted to 86.23%, CD5(-) cells amounted to 13.76%, ZAP-70 protein was expressed in 12 out of 50 patients. It is concluded that immunophenotypic data are very useful for the diagnosis and detection of minimal residual disease of B-CLL, and the relationship between the immunophenotypic characteristics and the prognosis of B-CLL needs further study.

Changed salt appetite and central angiotensin II-induced cellular activation in rat offspring following hypoxia during fetal stages.

Hypoxia in pregnancy may induce fetal growth restriction and cause functional abnormalities during development. The present study determined the long-term influence of hypoxia in fetal life on dipsogenic behavior linked to central angiotensin (Ang) network in the offspring rats. Fetal blood pO(2) and body weight were decreased by hypoxia during pregnancy, followed by a postnatal "catch-up" growth. Subcutaneous hypertonic saline or intracerebroventricular Ang II significantly increased salt intake in the offspring prenatally exposed to hypoxia, while water intake was the same between the two groups. Ang II-induced c-fos expression was detected in the paraventricular nuclei, median preoptic nuclei, supraoptic nuclei, and subfornical organ in the brain, in association with reduced forebrain AT(2) receptor protein abundance in the offspring prenatally exposed to hypoxia. Levels of central AT(1) receptor protein were not changed between the two groups. Hypoxia during pregnancy could be linked to developmental problems related to behavioral dysfunctions in body fluid regulations in later life, in association with the change in central angiotensin II-mediated neural activation and expression of the Ang II receptor in the brain.

[Role of Bcl-xL in the cathepsin D-associated apoptosis of K562 cells].

The purpose of study was to explore the possible functions of Bcl-xL in the glucosamine sulfate-induced apoptosis of chronic myeloid leukemia K562 cells. Light microscopy and Wright-Giemsa staining were used to investigate the morphologic evidences for apoptosis of K562 cells induced by glucosamine sulfate (GS); immunofluorescence was used to observe the translocation of cathepsin D and cytochrome C during the apoptosis; Western blot was performed to detect the expression of Bcl-xL, Bid, Bax in K562 cells treated by GS. The results showed that many vacuoles were observed in the cytoplasma of the K562 cells treated by GS; fluorescent signals of cathepsin D and cytochrome were fransformed from granules to disperse form by using immunofluorescence; the expression of Bcl-xL was found down-regulated in K562 cells treated by GS, but not in the cells pre-treated with pepstatin A; the significant changes were not detected in expression of Bax and Bid protein before or after apoptosis. It is concluded that Bcl-xL protein may mediate relationship between cathepsin D and mitochondia pathway, Cathepsin D may play an important role in the GS inducing apoptosis of K562 cells through downregulation of Bcl-xL expression.

2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose induces apoptosis in Hep G2 cells.

AIM: To determine the effect of 2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose (COPADG) on proliferation and apoptosis of human hepatocellular carcinoma cells (Hep G2). METHODS: Hep G2 cells were cultured in RPMI-1640 medium in the presence of various concentrations of COPADG. Cell proliferation was determined by MTT assay. Apoptosis was determined by fluorescence microscopy, transmission electron microscopy, agarose gel electrophoresis of DNA fragmentation, and flow cytometry. RESULTS: At the concentration ranging between 1-30 microM, COPADG potently inhibits growth and induce apoptosis of Hep G2 cells. CONCLUSIONS: COPADG could effectively induce apoptosis in Hep G2 cells. It may be potentially useful as a new agent for treatment of human hepatocellular carcinoma.

Effect of 2-(3-carboxy-1-oxopropyl) amino-2-deoxy-D-glucose on human esophageal cancer cell line.

AIM: To determine whether 2-(3-carboxy-1-oxopropy1) amino-2-deoxy-D-glucose (COPADG), a derivative of D-amino-glucose, inhibited the growth of human esophageal cancer cell line Eca-109. METHODS: Effects of COPADG on Eca-109 cells cultured in RPMI 1640 medium were examined by a tetrazolium-based colorimetric assay (MTT assay). RESULTS: COPADG inhibited the growth of Eca-109 cells in a dose- and time-dependent manner; the maximum inhibition rate was 83.75%. CONCLUSION: COPADG can directly inhibit the proliferation of Eca-109 cells, which may serve as the experimental evidence for development of new drugs for esophageal cancer therapy.