Induction of apoptosis by photoexcited tetracyclic compounds derivatives of benzo[b]thiophenes and pyridines

UVA-Induced DNA Damage and Apoptosis in Red Blood Cells of the African Catfish Clarias gariepinus

Ultraviolet-A light (UVA)-induced DNA damage and repair in red blood cells to investigate the sensitivity of African catfish to UVA exposure is reported. Fishes were irradiated with various doses of UVA light (15, 30, and 60 min day^-1 for 3 days). Morphological and nuclear abnormalities in red blood cells were observed in the fish exposed to UVA compared with controls. Morphological alterations such as acanthocytes, crenated cells, swollen cells, teardrop-like cells, hemolyzed cells, and sickle cells were observed. Those alterations were increased after 24 h exposure to UVA light and decreased at 14 days after exposure. The percentage of apoptosis was higher in red blood cells exposed to higher doses of UVA light. No micronuclei were detected, but small nuclear abnormalities such as deformed and eccentric nuclei were observed in some groups. We concluded that exposure to UVA light induced DNA damage, apoptosis, and morphological alterations in red blood cells in catfish; however, catfish were found to be less sensitive to UVA light than wild-type medaka.

The suppression of manganese superoxide dismutase decreased the survival of human glioblastoma multiforme T98G cells

Background: Glioblastoma multiforme (GBM) is a primary malignant brain tumor which has poor prognosis. High incidence of oxidative stress-based therapy resistance could be related to the high antioxidant status of GBM cells. Our previous study has reported that manganese superoxide dismutase (MnSOD) antioxidant expression was significantly higher in high grade glioma than in low grade. The aim of this study was to analyze the impact of MnSOD suppression toward GBM cell survival.Methods: This study is an experimental study using human glioblastoma multiforme T98G cell line. Suppression of MnSOD expression was performed using in vitro transfection MnSOD-siRNA. The MnSOD expression was analyzed by measuring the mRNA using real time RT-PCR, protein using ELISA technique, and specific activity of enzyme using inhibition of xantine oxidase. Concentration of reactive oxygen species (ROS) intracellular was determined by measuring superoxide radical and hydrogen peroxide. Cell survival was analyzed by measuring viability, proliferation, and cell apoptosis.Results: In vitro transfection of MnSOD-siRNA suppressed the mRNA, protein, and specific activity of MnSOD. This treatment significantly increased the concentration of superoxide radical; however, it did not influence the concentration of hydrogen peroxide. Moreover, viability MnSOD-suppressing cell significantly decreased, accompanied by increase of cell apoptosis without affecting cell proliferation.Conclusion: The suppression of MnSOD expression leads to decrease glioblastoma multiforme cell survival, which was associated to the increase of cell apoptotic.

Apoptosis and morphological alterations after UVA irradiation in red blood cells of p53 deficient Japanese medaka (Oryzias latipes)

Morphological alterations in red blood cells were described as hematological bioindicators of UVA exposure to investigate the sensitivity to UVA in wild type Japanese medaka (Oryzias latipes) and a p53 deficient mutant. The fewer abnormal red blood cells were observed in the p53 mutant fish under the control conditions. After exposure to different doses of UVA radiation (15min, 30min and 60min/day for 3days), cellular and nuclear alterations in red blood cells were analyzed in the UVA exposed fish compared with non-exposed controls and those alterations included acanthocytes, cell membrane lysis, swollen cells, teardrop-like cell, hemolyzed cells and sickle cells. Those alterations were increased after the UVA exposure both in wild type and the p53 deficient fish. Moreover, apoptosis analyzed by acridine orange assay showed increased number of apoptosis in red blood cells at the higher UVA exposure dose. No micronuclei but nuclear abnormalities as eccentric nucleus, nuclear budding, deformed nucleus, and bilobed nucleus were observed in each group. These results suggested that UVA exposure induced both p53 dependent and independent apoptosis and morphological alterations in red blood cells but less sensitive to UVA than Wild type in medaka fish.

Hematotoxic and biochemical effects of UVA on the Egyptian toad (Bufo regularis)

PURPOSE

To study the adverse impacts of ultraviolet radiation-A (UVA 320-400 nm) on some hematological and biochemical parameters of Bufo regularis was considered.

MATERIALS AND METHODS

Samples were classified into four groups: (i) Control; (ii) ultraviolet radiation (UVR)-treated group (for 3 days/for 15 min/day); (iii) UVR-treated group (for 3 days/for 30 min/day); and (iv) (for 3 days/for 60 min/day). The destructive effects of UVA radiation was evaluated by red blood cells (RBC) count, hemoglobin content (Hb), hematocrite (Ht), erythrocytic indices, white blood cells (WBC) count, total protein, glucose, aspartic amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), lactate dehyderogenase (LDH), glucose-6-phosphate dehyderogenase (G6PDH) and total bilribuin.

RESULTS

No mortality was observed. However, some physiological effects after the exposure to UVA were reported. The UVA-induced malformations recorded in the red blood cells included crenated cells (Cr), Acanthocytes (Ac), tear drop-like cells (Tr) and sickle cells (Sk).

CONCLUSION

The present study revealed the exposure to UVA from 15-60 min/day for three days could promote several biochemical and physiological disturbances as well as some changes in RBC.

Intratumoral hypoxic gradient drives stem cells distribution and MGMT expression in glioblastoma

Glioblastoma multiforme (GBM) are highly proliferative tumors currently treated by surgical removal, followed by radiotherapy and chemotherapy, which are counteracted by intratumoral hypoxia. Here we exploited image guided surgery to sample multiple intratumoral areas to define potential cellular heterogeneity in correlation to the oxygen tension gradient within the GBM mass. Our results indicate that more immature cells are localized in the inner core and in the intermediate layer of the tumor mass, whereas more committed cells, expressing glial fibrillary acidic protein and beta-III-tubulin, are distributed along the peripheral and neo-vascularized area, where Smad1/5/8 and Stat3 result to be activated. Moreover, GBM stem cells, identified with the stem cell marker CD133, express high level of DNA repair protein O6-methylguanine-DNA-methyltransferase (MGMT) known to be involved in chemotherapy resistance and highly expressed in the inner core of the tumor mass. Importantly, these cells and, particularly, CD133(+) cells result to be resistant to temozolomide (TMZ), the most used oral alkylating agent for the treatment of GBM, which specifically causes apoptosis only in GBM cells derived from the peripheral layer of the tumor mass. These results indicate a correlation between the intratumoral hypoxic gradient, the tumor cell phenotype, and the tumor resistance to chemotherapy leading to a novel concentric model of tumor stem cell niche, which may be useful to define the real localization of the chemoresistant GBM tumor cells in order to design more effective treatment strategies.

Hypoxia and succinate antagonize 2-deoxyglucose effects on glioblastoma

Glioblastoma multiforme (GBM) are highly proliferative brain tumors characterized by a hypoxic microenvironment which controls GBM stem cell maintenance. Tumor hypoxia promotes also elevated glycolytic rate; thus, limiting glucose metabolism is a potential approach to inhibit tumor growth. Here we investigate the effects mediated by 2-deoxyglucose (2-DG), a glucose analogue, on primary GBM-derived cells maintained under hypoxia. Our results indicate that hypoxia protects GBM cells from the apoptotic effect elicited by 2-DG, which raises succinate dehydrogenase activity thus promoting succinate level decrease. As a consequence hypoxia inducible factor-1α (HIF-1α) degradation occurs and this induces GBM cells to acquire a neuronal committed phenotype. By adding succinate these effects are reverted, as succinate stabilizes HIF-1α and increases GBM stem cell fraction particularly under hypoxia, thus preserving the tumor stem cell niche. 2-DG inhibits anaerobic glycolysis altering GBM cell phenotype by forcing tumor cells into mitochondrial metabolism and by inducing differentiation.

Reduction in glutathione peroxidase 4 increases life span through increased sensitivity to apoptosis

Glutathione peroxidase 4 (Gpx4) is an antioxidant defense enzyme that plays an important role in detoxification of oxidative damage to membrane lipids. Because oxidative stress is proposed to play a causal role in aging, we compared the life spans of Gpx4 heterozygous knockout mice (Gpx4(+/-) mice) and wild-type mice (WT mice). To our surprise, the median life span of Gpx4(+/-) mice (1029 days) was significantly longer than that of WT mice (963 days) even though the expression of Gpx4 was reduced approximately 50% in all tissues of Gpx4(+/-) mice. Pathological analysis revealed that Gpx4(+/-) mice showed a delayed occurrence of fatal tumor lymphoma and a reduced severity of glomerulonephritis. Compared to WT mice, Gpx4(+/-) mice showed significantly increased sensitivity to oxidative stress-induced apoptosis. Our data indicate that lifelong reduction in Gpx4 increased life span and reduced/retarded age-related pathology most likely through alterations in sensitivity of tissues to apoptosis.

Synthesis and antimicrobial activity studies of ortho-chlorodiarylamines and heteroaromatic tetracyclic systems in the benzo[b]thiophene series

ortho-Chlorodiarylamines in the 2,3,7-trimethylbenzo[b]thiophene series were prepared in high yields (70-85%) by C-N palladium-catalyzed cross-coupling using P(t-Bu)(3) as ligand and NaOt-Bu as base. A palladium-assisted C-C intramolecular cyclization of the coupling products gave thienocarbazoles and the dechlorinated diarylamines. Studies of antimicrobial activity of the compounds obtained, against representative species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus and Bacillus subtilis) and fungi (Candida albicans), were performed. We have also included in the biological assays some pyridine derivatives previously prepared by us, and it was possible to establish some structure-activity relationships (SARs).

Fluorescence of a benzothienopyridopyrimidone in solution and in lipid vesicles

Fluorescence properties of a biologically active benzothienopyridopyrimidone in solution and in lipid vesicles are reported. Assays at different pH values (0.5-10) allowed the determination of pK(a) = 2.0, showing that this compound may be useful as a pH indicator for pH < or = 4. In lipid vesicles, benzothienopyridopyrimidone locates in a water-rich environment, indicating that it can be carried in the hydrophilic region of liposomes for drug delivery applications.