Long-Term Excessive Selenium Supplementation Affects Gene Expression in Esophageal Tissue of Rats.

Esophageal cancer is one of the leading causes of cancer death and the seventh most prevalent cancer worldwide. Considering the positive association of high selenium with the prevalence of esophageal cancer, we have investigated the effect of high doses of selenium on gene expression in the normal esophageal tissue of rats. Twenty male rats were randomly divided into four groups: control group, group 2 mg Se/L, 10 mg Se/L, and 20 mg Se/L rats fed with a basal basic diet and 2, 10, and 20 mg Se/L as sodium selenite in drinking water, respectively, for 20 weeks. Serum malondialdehyde and glutathione peroxidase activity were measured. Moreover, the expression and concentration of the cyclin D1, cyclin E, KRAS, p53, NF-kB, TGF-ß, and MGMT in the esophageal tissue were analyzed and compared between the four groups. In normal esophageal tissue, selenium supplementations (2, 10, and 20 mg Se/L) increased the mRNA levels of cyclin D1, P53, KRAS, NF-κB p65, and MGMT and decreased the mRNA level of TGFß1. The concentrations of cyclin D1 and MGMT were also significantly increased by selenium supplementations. Selenium supplementations had no significant effect on serum MDA but significantly increased GPX activity. The present study suggests that selenium supplementation (2, 10, and 20 mg Se/L) affects gene expression related to inflammation, Cell proliferation, and apoptosis in the normal esophageal tissue. However, there were no observed abnormalities other than reduced growth with supplementation of 20 mg/L as Na2SeO3 in rats.

Kopetdaghinanes, pro-apoptotic hemiacetialic cyclomyrsinanes from Euphorbia kopetdaghi.

Euphorbia kopetdaghi grows wild in the Northeast parts of Iran. Phytochemical study of its aerial parts led to the isolation of two undescribed cyclomyrsinol macrocyclic diterpenes with a new tetrahydrofuran oxidation pattern containing a hemiacetal group named: kopetdaghinane A and B. The structure of the isolated compounds was elucidated by extensive spectroscopic methods. Cytotoxic activity of kopetdaghinane A was evaluated using standard MTT assay against MCF-7 breast cancer and OVCAR-3 ovary cells. HUVEC cells were used as a normal cell line for calculation of the selectivity index. The MTT showed cyclomyrsinol diterpene has a significant cytotoxic effect with good selectivity indexes against both cell lines but with more selectivity against MCF-7 cells. Apoptosis induction by cyclomyrsinol treatment was confirmed by annexin V-FITC/PI staining, and caspase-6 activation. Western blot analysis showed that the expression of Bcl-2 was noticeably decreased in response to kopetdaghinane A treatment, while the expression of Bax protein was increased. Moreover, the apoptotic effect of cyclomyrsinol was shown to be related to ROS production, and loss of mitochondrial membrane potential (ΔΨm). Taken together, these results showed that kopetdaghinane A inhibits the growth of MCF-7 breast cancer cells through the activation of the mitochondrial apoptotic pathway and may be considered as an investigational compound in breast cancer preclinical study.

Centaurea cyanus extracted 13-O-acetylsolstitialin A decrease Bax/Bcl-2 ratio and expression of cyclin D1/Cdk-4 to induce apoptosis and cell cycle arrest in MCF-7 and MDA-MB-231 breast cancer cell lines.

Natural products are considered recently as one of the source for production of efficient therapeutical agents for breast cancer treatment. In this study, a sesquiterpene lactone, 13-O-acetylsolstitialin A (13ASA), isolated from Centaurea cyanus, showed cytotoxic activities against MCF-7 and MDA-MB-231 breast cancer cell lines using standard 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. To find the mechanism of action of cytotoxicity, annexin V/propidium iodide (PI) staining was performed for evaluation of apoptosis. This process was further confirmed by immunoblotting of anti- and proapoptotic, Bcl-2 and Bax, proteins. Cell cycle arrest was evaluated by measurement of fluorescence intensity of PI dye and further confirmed by immunoblotting of Cdk-4 and cyclin D1. Mitochondrial transmembrane potential (ΔΨm) and generation of reactive oxygen species (ROS) were measured using the JC-1 and DCFDA fluorescence probes, respectively. These experiments showed that 13ASA is a potent cytotoxic agent, which activates apoptosis-mediated cell death. In response to this compound, Bax/Bcl-2 ratio was noticeably increased in MCF-7 and MDA-MB-231 cells. Moreover, 13ASA induced cell cycle arrest at subG1 and G1 phases by decreasing protein levels of cyclin D1 and Cdk-4. It was done possibly through the decrease of ΔΨm and increase of ROS levels which induce apoptosis. In conclusion, this study mentioned that 13ASA inhibit the growth of MCF-7 and MDA-MB-231 breast cancer cell lines through the induction of cell cycle arrest, which triggers apoptotic pathways. 13ASA can be considered as a susceptible compound for further investigation in breast cancer study.

New 6(17)-epoxylathyrane diterpene: aellinane from Euphorbia aellenii induces apoptosis via mitochondrial pathway in ovarian cancer cell line.

Euphorbia species have been used in traditional medicine in many countries for the treatment of cancer. This article aims to evaluate the capability of a new lathyrane diterpene isolated from Euphorbia aellenii to induce apoptosis in the Caov-4 cell line to determine the underlying mechanism of its anticancer effects. A new 6(17)-epoxylathyrane diterpenes: aellinane from Euphorbia aellenii was evaluated for viability of Caov-4 cells by MTT method. Apoptosis induction by lathyrane diterpene was confirmed by annexin V-FITC/PI staining, and caspase-6 activation. The Bcl2 and Bax protein content were detected by Western blot analysis. Finally, we employed the fluorescent ROS detection kit and fluorochrome JC-1 to determine ROS levels and loss of mitochondria membrane potential (ΔΨm) in Caov-4 cells, respectively. The results show that lathyrane diterpene has significant cytotoxic effect against Caov-4 cells. The IC50 value was 45 µM. Annexin V/propidium iodide (PI) staining and caspase-6 activity assay confirmed that lathyrane diterpene is able to induce apoptosis in Caov-4 cells. The results also demonstrate that lathyrane diterpene up-regulated Bax and down-regulated Bcl-2 proteins. Moreover, apoptotic effect of lathyrane diterpene was also related to ROS production and loss of mitochondrial membrane potential (ΔΨm). This study demonstrated that lathyrane diterpene has profound activity against Caov-4 cells. Analysis of apoptosis-related proteins revealed that lathyrane diterpene triggered the mitochondrion-mediated apoptosis pathway, which led to the loss of mitochondrial membrane potential (ΔΨm) and activation of caspase-6. Therefore, we believe that lathyrane diterpene might be a promising natural compound in ovarian cancer therapy.