The Effect of TIGAR Knockdown on Apoptotic and Epithelial-Mesenchymal Markers Expression in Doxorubicin-Resistant Non-Small Cell Lung Cancer A549 Cell Lines.

Resistance to chemotherapeutic drugs is a critical problem in cancer therapy, but the underlying mechanism has not been fully elucidated. TP53-induced glycolysis regulatory phosphatase (TIGAR), an important glycolysis and apoptosis regulator, plays a crucial role in cancer cell survival by protecting cells against oxidative stress-induced apoptosis. In the present study, we investigated whether TIGAR is involved in epithelial-mesenchymal transition (EMT) in doxorubicin (DOX)-resistant human non-small cell lung cancer (NSCLC), A549/DOX cells. We found that the expression of TIGAR was significantly higher in A549/DOX cells than in the parent A549 cell lines. siRNA-mediated TIGAR knockdown reduced migration, viability and colony survival of doxorubicin-resistant lung cancer cells. Also, TIGAR knockdown decreased pro-survival protein Bcl-2 and increased pro-apoptotic Bax and cleaved poly (ADP-ribose) polymerase (PARP). Moreover, TIGAR depletion significantly up-regulated both caspase-3 and caspase-9 expression. Furthermore, TIGAR depletion up-regulated the expression of E-cadherin and down-regulated the expression of vimentin. These results indicate that TIGAR knockdown may inhibit EMT in doxorubicin (DOX)-resistant human NSCLC and may represent a therapeutic target for a non-small lung cancer cells chemoresistance.

Poly(ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors Reduce Reactive Gliosis and Improve Angiostatin Levels in Retina of Diabetic Rats.

Diabetic retinopathy (DR) is a multifactorial disease characterized by reactive gliosis and disbalance of angiogenesis regulators, contributing to endothelial dysfunction and microvascular complications. This study was organized to elucidate whether poly(ADP-ribose) polymerase-1 (PARP-1) inhibition could attenuate diabetes-induced damage to macroglia and correct angiogenic disbalance in diabetic rat retina. After 8 weeks of streptozotocin (STZ)-induced diabetes, Wistar male rats were treated with PARP-1 inhibitors, nicotinamide (NAm) or 3-aminobenzamide (3-AB) (100 and 30 mg/kg/daily i.p., respectively), for 14 days. After the 10-weeks experiment period, retinas were undergone an immunohistochemical staining for glial fibrillary acidic protein (GFAP), while western blots were performed to evaluate effects of PAPR-1 inhibitors on the levels of PARP-1, poly(ADP-ribosyl)ated proteins (PARs), GFAP, and angiostatin isoforms. Diabetes induced significant up-regulation and activation of retinal PARP-1, reactive gliosis development, and GFAP overexpression compared to non-diabetic control. Moreover, extensive fragmentation of both PARP-1 and GFAP (hallmarks of apoptosis and macroglia reactivation, respectively) in diabetic retina was also observed. Levels of angiostatin isoforms were dramatically decreased in diabetic retina, sustaining aberrant pro-angiogenic condition. Both NAm and 3-AB markedly attenuated damage to macroglia, evidenced by down-regulation of PARP-1, PARs and total GFAP compared to diabetic non-treated group. PARP-1-inhibitory therapy prevented formation of PARP-1 and GFAP cleavage-derived products. In retinas of anti-PARP-treated diabetic animals, partial restoration of angiostatin's levels was shown. Therefore, PARP-1 inhibitors counteract diabetes-induced injuries and manifest retinoprotective effects, including attenuation of reactive gliosis and improvement of angiogenic status, thus, such agents could be considered as promising candidates for DR management.

Statin treatment decreases serum angiostatin levels in patients with ischemic heart disease.

AIM: Angiogenesis and chronic inflammation are known to be co-dependent in atherosclerosis and cardiovascular diseases. This study was undertaken to investigate whether simvastatin could affect serum levels of angiostatin, a potent endogenous inhibitor of neovascularization, in patients with ischemic heart disease (IHD). MAIN METHODS: Twenty-six patients with clinically confirmed IHD and hypercholesterolemia were assigned 40 mg/day of simvastatin for 8 weeks. Levels of lipid metabolism, C-reactive protein (C-RP) and other biochemical parameters in serum samples were measured using biochemical analyzer. Serum angiostatin levels were determined by Western blot. Association of serum angiostatin levels with total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and C-RP levels was evaluated. KEY FINDINGS: Simvastatin therapy improved the main parameters of lipid metabolism, including statistically significant (P < 0.05) reductions in TC (by 46%) and LDL-C (by 42%), and decreased inflammatory marker C-RP (by 32%), as compared with the baseline. Simvastatin treatment resulted in marked reduction of serum angiostatin level (by 80% in comparison with baseline, P < 0.05). Strong positive correlations between serum angiostatin level versus concentrations of TC, LDL-C, and C-RP were demonstrated before onset of the study (r = 0.48311, 0.6252, and 0.653, respectively) and after simvastatin therapy (r = 0.67752, 0.6485, and 0.8244, respectively). SIGNIFICANCE: We describe for the first time novel pleiotropic effect of statin therapy associated with decrease of serum angiostatin levels. Thus, circulating angiostatin represents an independent additional risk marker for cardiovascular events and could be applied as potential supplementary indicator for evaluation of statin therapy efficacy.

Protective effects of nanostructures of hydrated C(60) fullerene on reproductive function in streptozotocin-diabetic male rats.

Diabetes mellitus is a well-recognized cause of male sexual dysfunction and impairments of male fertility. Streptozotocin (STZ) is used for medical treatment of neoplastic islet ß-cells of pancreas and producing of animal model of diabetes mellitus type 1 that is characterized by suppression of reproductive activity due to the hyperglycaemia-induced oxidative stress and histopathological alterations in testes. Seeking for the agents that could alleviate diabetes-induced damage to reproductive system is yet the important area of inquiry. The present study was designed to evaluate whether hydrated C(60) fullerene (C(60)HyFn), which is known to be powerful bioantioxidant, eliminate testicular dysfunction induced by STZ-diabetes in rats. Wistar strain male albino rats were divided into four groups of six animals each: (1) control group, (2) C(60)HyFn-treated nondiabetic group, (3) STZ-diabetic group and (4) C(60)HyFn-treated diabetic group. Once hyperglycaemia was induced by STZ, rats in the second and fourth groups were treated with C(60)HyFn (in the form of drinking water) at the dose of 4µg/kg daily for 5 weeks. In diabetic rats, relative weights of right cauda epididymis, seminal vesicles, prostate, sperm motility and epididymal sperm concentration were significantly less than those of control group, but which were restored in the fourth group treated with C(60)HyFn (p<0.001). In hematoxylin and eosin staining, marked histopathological changes including degeneration, desquamation, disorganisation and reduction in germinal cells, interstitial oedema and congestion were evident in the testis of diabetic rats, but C(60)HyFn treatment resulted in recovery of histopathological changes and an increase in Johnsen's testicular score significantly (p<0.001). C(60)HyFn treatment restores the increased apoptosis induced by STZ-diabetes. In diabetic rats, levels of serum testosterone, testicular reduced glutathione (GSH) and alpha-tocopherol were significantly reduced and testicular lipid peroxidation level was increased (p<0.001). Nevertheless, treatment of diabetic rats with C(60)HyFn resulted in significant corrective effects on these parameters towards the control levels. C(60)HyFn, applied alone, did not exert any toxic effects in testicular tissues. Furthermore, C(60)HyFn treatment in diabetic and nondiabetic rats resulted in considerable elevations of some important polyunsaturated fatty acids. In conclusion, we have presented for the first time substantial evidence that administration of C(60)HyFn significantly reduces diabetes-induced oxidative stress and associated complications such as testicular dysfunction and spermatogenic disruption.

Peculiarities of the antioxidant and radioprotective effects of hydrated C60 fullerene nanostuctures in vitro and in vivo.

Aqueous solutions of highly stable supramolecular donor-acceptor complexes of chemically nonmodified pristine C(60) fullerene molecules with H(2)O molecules (hydrated C(60) fullerene-C(60)HyFn) and their labile nano-sized clusters were examined for their antioxidant effects on removal of hydroxyl radicals (.OH) and protecting DNA against oxidative damage induced by ionizing radiation in vitro. The suppressing influence of C(60)HyFn on the formation of OH-radicals in water exposed to X-rays at doses of 1-7 Gy was assessed by determination of oxidation levels of coumarin-3-carboxylic acid. C(60)HyFn demonstrates apparent antiradical activity in vitro in the range of concentrations of 10(-11)-10(-6) M. Paradoxically, the .OH-removing efficacy of C(60)HyFn was in reverse correlation with fullerene concentration. It was hypothesized that the antiradical action of C(60)HyFn in water medium generally is due to a "nonstoichiometric" mechanism, supposedly to a hydrated free radical recombination (self-neutralization), which is catalyzed by specific water structures ordered by C(60)HyFn. With the use of 8-oxoguanine as a marker of oxidative damage to DNA, it has been demonstrated that C(60)HyFn in concentrations of 10(-7)-10(-6) M protects nucleic acids against radical-induced damage. The second part of the present study was aimed to evaluate the overall radioprotective efficacy of C(60)HyFn in doses of 0.1 or 1 mg/kg b.w. injected intraperitoneally to mice either 1 h before or 15 min after lethal dose exposure of the X-ray (7 Gy) irradiation. Survival rate of the mice was observed at 30 day intervals after irradiation, while the weight gains of experimental animals were monitored as well. The most significant protective effect was demonstrated when 1 mg/kg dosage of C(60)HyFn was administered before irradiation. The outcome of the substance testing is 15% survival rate of irradiated animals at 30 days of observation, and prevention of noticeable weight loss characteristic for radiation impact, versus unprotected control animals. In conclusion, results of the study obviate that the apparent protective action of C(60)HyFn in vivo is determined by its considerable ability to decrease X-ray-generated reactive oxygen species. Based on the results and that neat C(60) is nontoxic, actually in the hydrated form, without side effects and with sufficient radioprotective effects in low doses, C(60)HyFn may be considered as a novel antioxidant agent, which substantially diminishes the harmful effects of ionizing radiation.

Nanostructures of hydrated C60 fullerene (C60HyFn) protect rat brain against alcohol impact and attenuate behavioral impairments of alcoholized animals.

It is well known that chronic ethyl alcohol (EtOH) consumption is capable to injure brain cells and to cause essential abnormalities in behavioral characteristics of animals addicted to alcohol. In this work we for the first time have shown that administration of aqueous solutions of hydrated C60 fullerenes (C60HyFn) with C60 concentration of 30nM as a drinking water during chronic alcoholization of rats (a) protects the tissues of central nervous system (CNS) from damage caused by oxidative stress with high efficacy, (b) prevents the pathological loss of both astrocytes (the main cells of CNS) and astrocytic marker, glial fibrillary acidic proteins (GFAP) and, as consequence, (c) due to their adaptogenic effects, C60HyFn significantly improves behavioral response and eliminates emotional deficits induced by chronic alcohol uptake. The wide range of beneficial biological effects, zero-toxicity, and efficacy even in super-small doses provide a rationale for the possible application of C60HyFn for the treatment of alcohol-induced encephalopathy as well as alcoholism prophylaxis.