Vitamin E modulates cigarette smoke extract-induced cell apoptosis in mouse embryonic cells

Vitamin E stabilizes iron and mitochondrial metabolism in pulmonary fibrosis

Introduction: Pulmonary fibrosis (PF) is a fatal chronic lung disease that causes structural damage and decreased lung function and has a poor prognosis. Currently, there is no medicine that can truly cure PF. Vitamin E (VE) is a group of natural antioxidants with anticancer and antimutagenic properties. There have been a few reports about the attenuation of PF by VE in experimental animals, but the molecular mechanisms are not fully understood. Methods: Bleomycin-induced PF (BLM-PF) mouse model, and cultured mouse primary lung fibroblasts and MLE 12 cells were utilized. Pathological examination of lung sections, immunoblotting, immunofluorescent staining, and real-time PCR were conducted in this study. Results: We confirmed that VE significantly delayed the progression of BLM-PF and increased the survival rates of experimental mice with PF. VE suppressed the pathological activation and fibrotic differentiation of lung fibroblasts and epithelial-mesenchymal transition and alleviated the inflammatory response in BLM-induced fibrotic lungs and pulmonary epithelial cells in vitro. Importantly, VE reduced BLM-induced ferritin expression in fibrotic lungs, whereas VE did not exhibit iron chelation properties in fibroblasts or epithelial cells in vitro. Furthermore, VE protected against mitochondrial dysmorphology and normalized mitochondrial protein expression in BLM-PF lungs. Consistently, VE suppressed apoptosis in BLM-PF lungs and pulmonary epithelial cells in vitro. Discussion: Collectively, VE markedly inhibited BLM-induced PF through a complex mechanism, including improving iron metabolism and mitochondrial structure and function, mitigating inflammation, and decreasing the fibrotic functions of fibroblasts and epithelial cells. Therefore, VE presents a highly potential therapeutic against PF due to its multiple protective effects with few side effects.

Modulation of cigarette smoke extract-induced human bronchial epithelial damage by eucalyptol and curcumin

Smoking is one of the most important leading death cause worldwide. From a toxicological perspective, cigarette smoke serves hazards especially for the human being exposed to passive smoke. Over the last decades, the effects of natural compounds on smoking-mediated respiratory diseases such as COPD, asthma, and lung cancer have been under investigation, as well as the mechanistic aspects of disease progression. In the present study, the protective mechanism of eucalyptol (EUC), curcumin (CUR), and their combination on BEAS-2B cells were investigated in vitro to understand their impact on cell death, oxidative cell injury, and inflammatory response induced by 3R4F reference cigarette extract (CSE). According to the present findings, EUC, CUR, and their combination improved cell viability, attenuated CSE-induced apoptosis, and LC3B expression. Further, CSE-induced oxidative damage and inflammatory response in human bronchial epithelial cells were remarkably reduced by the combination treatment through modification of enzymatic antioxidant activity, GSH, MDA, and intracellular ROS levels as well as nitrite and IL-6 levels. In addition, nuclear translocation of Nrf2, a regulatory protein involved in the indirect antioxidant response, was remarkably up-regulated with the combination pre-treatment. In conclusion, EUC and CUR in combination might be a potential therapeutic against smoking-induced lung diseases through antioxidant and inflammatory pathways and results represent valuable background for future in vivo pulmonary toxicity studies.

Vitamin E preconditioning alleviates in vitro thermal stress in cultured human epidermal keratinocytes

AIMS

Thermal burns are the most common type of skin injuries. Clinically, the deteriorating thermal wounds have been successfully treated with skin cell sheets, suspensions or bioengineered skin substitutes. After thermal injury, oxidative microenvironment prevalent in the burnt tissue due to imbalance between production of free radicals and antioxidants defense aiding to destruction of cellular or tissue components. However, depleted antioxidant content particularly vitamin E after heat injury challenges efficient regenerative and healing capacity of transplanted cells. Thus, aim of current study was to pretreat human epidermal keratinocytes with vitamin E in order to enhance their survival rate and therapeutic ability under oxidative microenvironment induced by in vitro heat stress.

MAIN METHODS

Keratinocytes were treated with 100 μM vitamin E at 37 °C for 24 h followed by thermal stress at 51 °C for 10 min. Cell viability and cytotoxicity assays, gene expression analysis and paracrine release analysis were performed.

KEY FINDINGS

Vitamin E preconditioning resulted in significantly improved cell morphology, enhanced viability and reduced lactate dehydrogenase release. Furthermore, Vitamin E preconditioned cells exposed to thermal stress showed significant down-regulated expression of BAX and up-regulated expression of PCNA, BCL-XL, vascular endothelial growth factor (VEGF), involucrin, transglutaminase 1 (TGM1) and filaggrin (FLG) escorted by increased paracrine release of VEGF, basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF).

SIGNIFICANCE

Results of the current study suggest that clinical transplantation of vitamin E preconditioned keratinocytes alone or in combination with dermal fibroblasts in skin substitutes for the treatment of thermally injured skin.

Tumors arise from the excessive repair of damaged stem cells

Although many hypotheses for tumorigenesis have been proposed, none can explain the occurrence and development of tumors comprehensively until now. We put forward a new hypothesis: tumors arise from the excessive repair of damaged stem cells. There are stem cells in all tissues and organs, and the stem cells have perfect damage repair mechanisms, including damage repair systems and repair-inhibiting systems. Tumors arise from the excessive repair of damaged stem cells, i.e., carcinogens induce stem cell damage, leading to overexpression of damage repair systems, and simultaneous inactivation of repair-inhibiting systems through genetic or non-genetic mechanisms, finally forming tumors. The outcome (forming clinically significant tumors or death) and development (tumor recurrence, metastasis or spontaneous healing) of the tumor cells depends on whether the injury and the excessive repair persists, whether immune surveillance function is normal and the tumor microenvironment is appropriate. This hypothesis not only addresses the issues of where tumor cells arise from, how tumors form and where they go, but also provides a reasonable explanation for many unresolved issues in tumor occurrence, development, metastasis or healing. In addition, this hypothesis could guide the early diagnosis, reasonable treatment and effective prevention of tumors.

Putrescine treatment reverses α-tocopherol-induced desynchronization of polyamine and retinoid metabolism during rat liver regeneration

Background

The pre-treatment with α-tocopherol inhibits progression of rat liver proliferation induced by partial hepatectomy (PH), by decreasing and/or desynchronizing cyclin D1 expression and activation into the nucleus, activation and nuclear translocation of STAT-1 and -3 proteins and altering retinoid metabolism. Interactions between retinoic acid and polyamines have been reported in the PH-induced rat liver regeneration. Therefore, we evaluated the effect of low dosage of α-tocopherol on PH-induced changes in polyamine metabolism.

Methods

This study evaluated the participation of polyamine synthesis and metabolism during α-tocopherol-induced inhibition of rat liver regeneration. In PH-rats (Wistar) treated with α-tocopherol and putrescine, parameters indicative of cell proliferation, lipid peroxidation, ornithine decarboxylase expression (ODC), and polyamine levels, were determined.

Results

Pre-treatment with α-tocopherol to PH-animals exerted an antioxidant effect, shifting earlier the increased ODC activity and expression, temporally affecting polyamine synthesis and ornithine metabolism. Whereas administration of putrescine induced minor changes in PH-rats, the concomitant treatment actually counteracted most of adverse actions exerted by α-tocopherol on the remnant liver, restituting its proliferative potential, without changing its antioxidant effect. Putrescine administration to these rats was also associated with lower ODC expression and activity in the proliferating liver, but the temporally shifting in the amount of liver polyamines induced by α-tocopherol, was also “synchronized” by the putrescine administration. The latter is supported by the fact that a close relationship was observed between fluctuations of polyamines and retinoids.

Conclusions

Putrescine counteracted most adverse actions exerted by α-tocopherol on rat liver regeneration, restoring liver proliferative potential and restituting the decreased retinoid levels induced by α-tocopherol. Therefore interactions between polyamines and retinol, mediated by the oxidant status, should be taken into consideration in the development of new therapeutic strategies for pathologies occurring with liver cell proliferation.

Rapid shedding of proinflammatory microparticles by human mononuclear cells exposed to cigarette smoke is dependent on Ca2+ mobilization

OBJECTIVES

Microparticles are membrane vesicles shed by cells upon activation and apoptosis. Agonists capable of inducing microparticle generation include cytokines, bacterial products, P-selectin, histamine. Cigarette smoke extract has also been recognized as an agonist involved in microparticle generation with an apoptosis-dependent mechanism. We investigated the possibility that cigarette smoke extract induces the rapid generation of proinflammatory microparticles by human mononuclear cells with a calcium-dependent mechanism.

MATERIALS AND METHODS

Human mononuclear cells were exposed to cigarette smoke extract. [Ca(2+)]i mobilization was assessed with the fluorescent probe Fluo-4 NW. Microparticles were quantified with a prothrombinase assay and by flow cytometry. Normal human bronchial epithelial cells and A549 alveolar cells were incubated with cigarette smoke extract-induced microparticles and the generation of ICAM-1, IL-8, and MCP-1 was assessed by ELISA.

RESULTS

Exposure to cigarette smoke extract induced a rapid increase in [Ca(2+)]i mobilization. Microparticle generation was also increased. EGTA, verapamil and the calmodulin inhibitor, W-7, inhibited microparticle generation. Incubation of lung epithelial cells with cigarette smoke extract-induced microparticles increased the expression of proinflammatory mediators.

CONCLUSIONS

Exposure of mononuclear cells to cigarette smoke extract causes a rapid shedding of microparticles with a proinflammatory potential that might add to the mechanisms of disease from tobacco use.

Tocopherols and tocotrienols as anticancer treatment for lung cancer: future nutrition

Nutrition has been known for ages to shield the immune system against several formulations that deregulate normal DNA repair mechanisms, and induce tumorigenesis. Vitamins and in specific Vit E and its members tocopherols (α-, β-, γ-, δ-) and tocotrienols (α-, β-, γ-, δ-) have demonstrated strong association with the prevention of cancer and inhibition of tumor, both in vitro and in vivo. Vitamin E has also demonstrated effective role against chemotherapy resistant cancer cell evolution and a protective role in acute interstitial disease. Several formulations of Vitamin E have been investigated conjugated with different carriers as nano-formulations and administered in different forms. Additionally, several tumorigenic pathways have been investigated separately in an effort to identify which member of Vitamin E inhibits efficiently every pathway. Vitamin E presented efficiency against specific subhistology types of lung cancer. Finally, in the current work up to date information regarding novel formulations with Vitamin E and inhibition pathways are going to be presented and commented.

Trolox contributes to Nrf2-mediated protection of human and murine primary alveolar type II cells from injury by cigarette smoke

Cigarette smoke (CS) is a main risk factor for chronic obstructive pulmonary disease (COPD). Oxidative stress induced by CS causes DNA and lung damage. Oxidant/antioxidant imbalance occurs in the distal air spaces of smokers and in patients with COPD. We studied the effect of oxidative stress generated by CS both in vivo and in vitro on murine primary alveolar type II (ATII) cells isolated from nuclear erythroid 2-related factor-2 (Nrf2)(-/-) mice. We determined human primary ATII cell injury by CS in vitro and analyzed ATII cells isolated from smoker and non-smoker lung donors ex vivo. We also studied whether trolox (water-soluble derivative of vitamin E) could protect murine and human ATII cells against CS-induced DNA damage and/or decrease injury. We analyzed oxidative stress by 4-hydroxynonenal expression, reactive oxygen species (ROS) generation by Amplex Red Hydrogen Peroxide Assay, Nrf2, heme oxygenase 1, p53 and P53-binding protein 1 (53BP1) expression by immonoblotting, Nrf2 nuclear translocation, Nrf2 and p53 DNA-binding activities, apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and cytokine production by ELISA. We found that ATII cells isolated from Nrf2(-/-) mice are more susceptible to CS-induced oxidative DNA damage mediated by p53/53BP1 both in vivo and in vitro compared with wild-type mice. Therefore, Nrf2 activation is a key factor to protect ATII cells against injury by CS. Moreover, trolox abolished human ATII cell injury and decreased DNA damage induced by CS in vitro. Furthermore, we found higher inflammation and p53 mRNA expression by RT-PCR in ATII cells isolated from smoker lung donors in comparison with non-smokers ex vivo. Our results indicate that the Nrf2 and p53 cross talk in ATII cells affect the susceptibility of these cells to injury by CS. Trolox can protect against oxidative stress, genotoxicity and inflammation induced by CS through ROS scavenging mechanism, and serve as a potential antioxidant prevention strategy against oxidative injury of ATII cells in CS-related lung diseases.

Plants vs. cancer: a review on natural phytochemicals in preventing and treating cancers and their druggability

Cancer remains to be one of the leading causes of death in the United States and around the world. The advent of modern drug-targeted therapies has undeniably improved cancer patients' cares. However, advanced metastasized cancer remains untreatable. Hence, continued searching for a safer and more effective chemoprevention and treatment is clearly needed for the improvement of the efficiency and to lower the treatment cost for cancer care. Cancer chemoprevention with natural phytochemical compounds is an emerging strategy to prevent, impede, delay, or cure cancer. This review summarizes the latest research in cancer chemoprevention and treatment using the bioactive components from natural plants. Relevant molecular mechanisms involved in the pharmacological effects of these phytochemicals are discussed. Pharmaceutical developmental challenges and opportunities in bringing the phytochemicals into the market are also explored. The authors wish to expand this research area not only for their scientific soundness, but also for their potential druggability.

Ursolic acid inhibits cigarette smoke extract-induced human bronchial epithelial cell injury and prevents development of lung cancer

Cigarette smoking is the main cause of chronic obstructive pulmonary disease and lung cancer. The present study was aimed to explore the chemopreventive effect of ursolic acid (UA) on these diseases. In the CSE treated normal human bronchial epithelial cell model, UA alleviated cytotoxicity caused by CSE, recovered the intracellular redox balance, and relieved the stimulation of external deleterious factors as well. UA mitigated CSE-induced DNA damage through the Nrf2 (nuclear factor erythroid 2-related factor 2) pathway. Moreover, UA inhibited lung cancer development in the model established by A549 cells in nude mice in vivo. For the first time, our results indicate that UA could be developed as a potential lung cancer chemopreventive agent.