α-Tocopherol administration blocks adaptive changes in cell NADH/NAD+ redox state and mitochondrial function leading to inhibition of gastric mucosa cell proliferation in rats

Lactate-stimulated ethanol oxidation: Revisiting an old hypothesis

Liver slices from starved rats and incubated without other substrates oxidized ethanol at a rate of 4.1 µmols • h^-1 • g^-1. Addition of 10 mmols • L^-1 lactate increased this rate 2-fold. 4-methylpyrazole (4-MP), an alcohol dehydrogenase (ADH) inhibitor, drastically decreased the rate of ethanol oxidation, but did not inhibit the stimulation due to lactate. In the same context, liver acetaldehyde production, as the main by-product of ethanol oxidation, appeared to be much less inhibited by 4-MP in the presence of lactate. Aminotriazole (a catalase inhibitor), however, completely inhibited the stimulation. Furthermore, 2-hydroxybut-3-ynoate, an alpha-hydroxy acid oxidase inhibitor, completely abolished the stimulated ethanol oxidation promoted by lactate. Moreover, to determine the origin of the H₂O₂ produced, we did liver subcellular fractionation and then analyzed their content in peroxisomes, mitochondria and catalase. We observed that cytoplasm and peroxisomes appears to be the main producers of H₂O₂, and that the acceleration of ethanol oxidation by lactate is completely dependent on catalase. In conclusion, the H₂O₂ necessary to boost the catalase-dependent oxidation of ethanol appears to come from cytoplasm and peroxisomes, and is produced by the enzyme lactate oxidase.

High α-tocopherol dosing increases lipid metabolism by changing redox state in damaged rat gastric mucosa and liver after ethanol treatment

Regeneration of ethanol-injured rat gastric mucosa must undergo changes in major metabolic pathways to achieve DNA replication and cell proliferation. These events are highly dependent on glucose utilization and inhibited by vitamin E (VE) (α-tocopherol) administration. Therefore, the present study aimed at assessing lipid metabolism in the gastric mucosa and ethanol-induced gastric damage and the effect of α-tocopherol administration. For this, rates of fatty acid β-oxidation and lipogenesis were tested in gastric mucosa samples. Through histological analysis, we found loss of the mucosa's superficial epithelium, which became gradually normalized during the recovery period. Proliferation of gastric mucosa occurred with augmented formation of β-oxidation by-products, diminished synthesis of triacylglycerols (TGs), as well as of phospholipids, and a reduced cytoplasmic NAD/NADH ratio, whereas the mitochondrial redox NAD/NADH ratio was much less affected. In addition, α-tocopherol increased palmitic acid utilization in the gastric mucosa, which was accompanied by the induction of 'mirror image' effects on the cell redox state, reflected in an inhibited cell gastric mucosa proliferation by the vitamin administration. In conclusion, the present study shows, for the first time, the role of lipid metabolism in the adaptive cell gastric mucosa changes that drive proliferation after a chronic insult. Moreover, α-tocopherol increased gastric mucosa utilization of palmitic acid associated with energy production. These events could be associated with its antioxidant properties in co-ordination with regulation of genes and cell pathways, including changes in the cell NAD/NADH redox state.

Mitochondrial Biogenesis in Response to Chromium (VI) Toxicity in Human Liver Cells

Hexavalent chromium (Cr(VI)) is a ubiquitous environmental pollutant, which poses a threat to human public health. Recent studies have shown that mitochondrial biogenesis can be activated by inflammatory and oxidative stress. However, whether mitochondrial biogenesis is involved in Cr(VI)-induced hepatotoxicity is unclear. Here, we demonstrated the induction of inflammatory response and oxidative stress, as indicated by upregulation of inflammatory factors and reactive oxygen species (ROS). Subsequently, we demonstrated that mitochondrial biogenesis, comprising the mitochondrial DNA copy number and mitochondrial mass, was significantly increased in HepG2 cells exposed to low concentrations of Cr(VI). Expression of genes related to mitochondrial function complex I and complex V was upregulated at low concentrations of Cr(VI). mRNA levels of antioxidant enzymes, including superoxide dismutase 1 and 2 (SOD1 and SOD2, respectively), kech like ECH associate protein 1 (KEAP1) and nuclear respiratory factor 2 (NRF-2), were also upregulated. Consistent with the above results, mRNA and protein levels of key transcriptional regulators of mitochondrial biogenesis such as the peroxisome-proliferator-activated receptor γ coactivator-1α (PGC-1α), NRF-1 and mitochondrial transcription factor A (TFAM) were increased by low concentrations of Cr(VI) in HepG2 cells. Moreover, we found that PGC-1α and NRF-1 tended to translocate into the nucleus. The expression of genes potentially involved in mitochondrial biogenesis pathways, including mRNA level of silent information regulator-1 (SIRT1), forkhead box class-O (FOXO1), threonine kinase 1 (AKT1), and cAMP response element-binding protein (CREB1), was also upregulated. In contrast, mitochondrial biogenesis was inhibited and the expression of its regulatory factors and antioxidants was downregulated at high and cytotoxic concentrations of Cr(VI) in HepG2 cells. It is believed that pretreatment with α-tocopherol could be acting against the mitochondrial biogenesis imbalance induced by Cr(VI). In conclusion, our study suggests that the homeostasis of mitochondrial biogenesis may be an important cellular compensatory mechanism against Cr(VI)-induced toxicity and a promising detoxification target.

Analysis of cancer-related lncRNAs using gene ontology and KEGG pathways

BACKGROUND

Cancer is a disease that involves abnormal cell growth and can invade or metastasize to other tissues. It is known that several factors are related to its initiation, proliferation, and invasiveness. Recently, it has been reported that long non-coding RNAs (lncRNAs) can participate in specific functional pathways and further regulate the biological function of cancer cells. Studies on lncRNAs are therefore helpful for uncovering the underlying mechanisms of cancer biological processes.

METHODS

We investigated cancer-related lncRNAs using gene ontology (GO) terms and KEGG pathway enrichment scores of neighboring genes that are co-expressed with the lncRNAs by extracting important GO terms and KEGG pathways that can help us identify cancer-related lncRNAs. The enrichment theory of GO terms and KEGG pathways was adopted to encode each lncRNA. Then, feature selection methods were employed to analyze these features and obtain the key GO terms and KEGG pathways.

RESULTS

The analysis indicated that the extracted GO terms and KEGG pathways are closely related to several cancer associated processes, such as hormone associated pathways, energy associated pathways, and ribosome associated pathways. And they can accurately predict cancer-related lncRNAs.

CONCLUSIONS

This study provided novel insight of how lncRNAs may affect tumorigenesis and which pathways may play important roles during it. These results could help understanding the biological mechanisms of lncRNAs and treating cancer.

Nasal mucosa healing after endoscopic sinus surgery in chronic rhinosinusitis of elderly patients: role of topic alpha-tocopherol acetate

BACKGROUND

Chronic rhinosinusitis (CRS) in European country ranges in elderly patients from 4.5 to 12% of population and has a significant effect on quality of life. In these patients, rhinosinusitis is linked to immune functions changes with age and to mucosal paraphysiological alterations such as crusting formations with atrophic epithelium, variations of nasal airflow and modifications of the mucociliary clearance. Failure of medical treatments leads to surgery in patients with persistent symptoms and radiographic signs of CRS. The choice of appropriate post-surgical topic treatments is important for healing time and for preventing mucosal complications such as synechiae, crusting formation and atrophy with secondary bacterial and fungal infections.

AIMS

Defining the effects of topic alpha-tocopherol acetate administration on nasal mucosa healing after endoscopic sinus surgery in CRS of elderly patients.

METHODS

In this study were included 32 patients, mean age 68.6, who underwent FESS because affected by CRS not responsive to medical treatments. After surgical treatment, we distinguish two groups basing on local nasal therapy.

RESULTS

We investigated, in the postoperative time, the role of alpha-tocopherol acetate compared to gomenol oil. Follow-up was performed at 7-15 days and 1-3 months after surgery. We evaluated mucosal restoration using Rhinoscopy Sum Score and quality of life using Nasal Six Items Symptom Questionnaire. We observed a faster healing time and less recurrence of complications in patients who underwent topic treatment with alpha-tocopherol acetate.

DISCUSSION

In our research, we observed that alpha-tocopherol acetate has no contraindications and side effects.

CONCLUSIONS

Our study showed the effectiveness of alpha-tocopherol acetate topic treatment in elderly patients affected by CRS after FESS, in improving and speeding up the process of restoring the sinonasal mucosa, compared to another topic medication.

Apoptotic induction and inhibition of NF-κB signaling pathway in human prostatic cancer PC3 cells by natural compound 2,2'-oxybis (4-allyl-1-methoxybenzene), biseugenol B, from Litsea costalis: an in vitro study

Litsea is considered as an evergreen genus distributed in tropical and subtropical Asia; this genus belongs to the large family of Lauraceae. In this study, the cell-death metabolism of biseugenol B was investigated. Nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and release of cytochrome c have been detected in human prostate cancer cell line (PC3) treated with biseugenol B by high content screening (HCS). Fluorescent analysis was conducted to examine the reactive oxygen species formation. To determine the mechanism of cell death, the levels of Bcl-cell lymphoma (Bcl)-2 proteins, Bcl-2-associated X (Bax) protein and anti-apoptosis heat-shock protein 70 were tested by applying reverse transcription polymerase chain reaction and Western blot. Bioluminescent assays were also performed to assess the level of caspases such as 3/7, 8 and 9 during treatment. Furthermore, the involvement of nuclear factor kappa-B (NF-κB) was examined by Western blot and HCS. Biseugenol B showed significant cytotoxicity toward PC3 with no toxicity toward normal prostate cells (RWPE-1), which indicates that biseugenol B has qualities that induce apoptosis in tumor cells. The treatment of PC3 cells with biseugenol B provoked apoptosis with cell-death-transducing signals. Downregulation of Bcl-2 and upregulation of Bax regulated the MMP, which in turn caused the release of cytochrome c from mitochondria into cytosol. The release of cytochrome c activated caspase-9, which consequently activated caspase-3/7 with the cleaved poly(ADP-ribose) polymerase protein, thereby resulting in apoptosis alteration. Involvement of an extrinsic apoptosis pathway was exhibited by the increase in caspase-8, while the increase in caspase-3/7 and caspase-9 demonstrated involvement of an intrinsic apoptosis pathway. Meanwhile, no significant increase was observed in caspases 3/7, 8 or 9 in normal prostate cells (RWPE-1) after treatment with biseugenol B. Prevention of NF-κB translocation from the cytosol to the nucleus occurred in PC3 after treatment with biseugenol B. The results of our study reveal that biseugenol B triggers the apoptosis of PC3 cells via intrinsic and extrinsic apoptosis pathways and inhibition of NF-κB signaling pathway. Our findings suggest that biseugenol B is a potentially useful agent for prostate cancer treatment.

Alcohol Withdrawal and Cerebellar Mitochondria

Cerebellar disorders trigger the symptoms of movement problems, imbalance, incoordination, and frequent fall. Cerebellar disorders are shown in various CNS illnesses including a drinking disorder called alcoholism. Alcoholism is manifested as an inability to control drinking in spite of adverse consequences. Human and animal studies have shown that cerebellar symptoms persist even after complete abstinence from drinking. In particular, the abrupt termination (ethanol withdrawal) of long-term excessive ethanol consumption has shown to provoke a variety of neuronal and mitochondrial damage to the cerebellum. Upon ethanol withdrawal, excitatory neurotransmitter molecules such as glutamate are overly released in brain areas including cerebellum. This is particularly relevant to the cerebellar neuronal network as glutamate signals are projected to Purkinje neurons through granular cells that are the most populated neuronal type in CNS. This excitatory neuronal signal may be elevated by ethanol withdrawal stress, which promotes an increase in intracellular Ca(2+) level and a decrease in a Ca(2+)-binding protein, both of which result in the excessive entry of Ca(2+) to the mitochondria. Subsequently, mitochondria undergo a prolonged opening of mitochondrial permeability transition pore and the overproduction of harmful free radicals, impeding adenosine triphosphate (ATP)-generating function. This in turn provokes the leakage of mitochondrial molecule cytochrome c to the cytosol, which triggers a cascade of adverse cytosol reactions. Upstream to this pathway, cerebellum under the condition of ethanol withdrawal has shown aberrant gene modifications through altered DNA methylation, histone acetylation, or microRNA expression. Interplay between these events and molecules may result in functional damage to cerebellar mitochondria and consequent neuronal degeneration, thereby contributing to motoric deficit. Mitochondria-targeting research may help develop a powerful new therapy to manage cerebellar disorders associated with hyperexcitatory CNS disorders like ethanol withdrawal.

Involvement of NF-κB and HSP70 signaling pathways in the apoptosis of MDA-MB-231 cells induced by a prenylated xanthone compound, α-mangostin, from Cratoxylum arborescens

Background

Cratoxylum arborescens has been used traditionally in Malaysia for the treatment of various ailments.

Methods

α-Mangostin (AM) was isolated from C. arborescens and its cell death mechanism was investigated. AM-induced cytotoxicity was observed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Acridine orange/propidium iodide staining and annexin V were used to detect cells in early phases of apoptosis. High-content screening was used to observe the nuclear condensation, cell permeability, mitochondrial membrane potential, and cytochrome c release. The role of caspases-3/7, -8, and -9, reactive oxygen species, Bcl-2 and Bax expression, and cell cycle arrest were also investigated. To determine the role of the central apoptosis-related proteins, a protein array followed by immunoblot analysis was conducted. Moreover, the involvement of nuclear factor-kappa B (NF-κB) was also analyzed.

Results

Apoptosis was confirmed by the apoptotic cells stained with annexin V and increase in chromatin condensation in nucleus. Treatment of cells with AM promoted cell death-transducing signals that reduced MMP by downregulation of Bcl-2 and upregulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol. The released cytochrome c triggered the activation of caspase-9 followed by the executioner caspase-3/7 and then cleaved the PARP protein. Increase of caspase-8 showed the involvement of extrinsic pathway. AM treatment significantly arrested the cells at the S phase (P<0.05) concomitant with an increase in reactive oxygen species. The protein array and Western blotting demonstrated the expression of HSP70. Moreover, AM significantly blocked the induced translocation of NF-κB from cytoplasm to nucleus.

Conclusion

Together, the results demonstrate that the AM isolated from C. arborescens inhibited the proliferation of MDA-MB-231 cells, leading to cell cycle arrest and programmed cell death, which was suggested to occur through both the extrinsic and intrinsic apoptosis pathways with involvement of the NF-κB and HSP70 signaling pathways.

α-Mangostin from Cratoxylum arborescens demonstrates apoptogenesis in MCF-7 with regulation of NF-κB and Hsp70 protein modulation in vitro, and tumor reduction in vivo

Cratoxylum arborescens is an equatorial plant belonging to the family Guttiferae. In the current study, α-Mangostin (AM) was isolated and its cell death mechanism was studied. HCS was undertaken to detect the nuclear condensation, mitochondrial membrane potential, cell permeability, and the release of cytochrome c. An investigation for reactive oxygen species formation was conducted using fluorescent analysis. To determine the mechanism of cell death, human apoptosis proteome profiler assay was conducted. In addition, using immunofluorescence and immunoblotting, the levels of Bcl-2-associated X protein (Bax) and B-cell lymphoma (Bcl)-2 proteins were also tested. Caspaces such as 3/7, 8, and 9 were assessed during treatment. Using HCS and Western blot, the contribution of nuclear factor kappa-B (NF-κB) was investigated. AM had showed a selective cytotoxicity toward the cancer cells with no toxicity toward the normal cells even at 30 μg/mL, thereby indicating that AM has the attributes to induce cell death in tumor cells. The treatment of MCF-7 cells with AM prompted apoptosis with cell death-transducing signals. This regulated the mitochondrial membrane potential by down-regulation of Bcl-2 and up-regulation of Bax, thereby causing the release of cytochrome c from the mitochondria into the cytosol. The liberation of cytochrome c activated caspace-9, which, in turn, activated the downstream executioner caspace-3/7 with the cleaved poly (ADP-ribose) polymerase protein, thereby leading to apoptotic alterations. Increase of caspace 8 had showed the involvement of an extrinsic pathway. This type of apoptosis was suggested to occur through both extrinsic and intrinsic pathways and prevention of translocation of NF-κB from the cytoplasm to the nucleus. Our results revealed AM prompt apoptosis of MCF-7 cells through NF-κB, Bax/Bcl-2 and heat shock protein 70 modulation with the contribution of caspaces. Moreover, ingestion of AM at (30 and 60 mg/kg) significantly reduced tumor size in an animal model of breast cancer. Our results suggest that AM is a potentially useful agent for the treatment of breast cancer.