Kadriye Akgün-Dar

Apoptosis-inducing effects of Morinda citrifolia L. and doxorubicin on the Ehrlich ascites tumor in Balb-c mice.

Morinda citrifolia L. (Noni) is a herbal remedy with promising anti‐cancer properties. However, its effects on various cancers are to be investigated to make a firm conclusion before implementing it into the clinical practice. Therefore, we investigated the cytotoxic potential of noni on Ehrlich ascites tumor grown in female Balb‐c mice and also combined it with a potent anti‐cancer agent, doxorubicin. One group received noni only (n = 8), another one doxorubicin (n = 8), and the other one noni + doxorubicin (n = 8) for 14 days after the inoculation of cells. The control group (n = 7) received 0.9% NaCl only. We found that short and long diameters of the tumor tissues were about 40–50% smaller, compared to those in control group. This anti‐growth effect resulted from the induction of apoptosis, which was confirmed by the positive results from the Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling (TUNEL) analysis and the active caspase‐3 cells in tissues. Apoptosis also confirmed by caspase‐cleaved cytokeratin 18 elevation in serum of the treated groups. Further, the proliferation was decreased, which was immunohistochemically shown by the PCNA staining. We conclude that noni may be useful in the treatment of breast cancer either on its own or in combination with doxorubicin. Further studies are warranted to assess the dosage and safety of using noni fruit juice in conjuction with anti‐cancer drugs against breast cancer. Copyright

Long term consequences on spatial learning-memory of low-calorie diet during adolescence in female rats; hippocampal and prefrontal cortex BDNF level, expression of NeuN and cell proliferation in dentate gyrus.

Calorie restriction (CR) is argued to positively affect general health, longevity and normally occurring age-related reduction of cognition. Obesity during adolescence may adversely affect cognition in adulthood but, to date effects of CR have not been investigated. We hypothesized that feeding with as low as 15% low-calorie diet (LCD) during adolescence would increase hippocampal and prefrontal BDNF (Brain-derived neurotrophic factor) levels, proliferative cells and neuron numbers in dentate gyrus (DG), thus positively affecting spatial memory in adulthood. Spatial learning-memory function was improved in adult female Sprague-Dawley rats fed with LCD during adolescence. PCNA (Proliferating cell nuclear antigen-cell proliferation marker) expressing cells and NeuN (Neuronal nuclear antigen-neuron marker) expressing cells in hippocampus DG which are critically involved in memory were increased. Hippocampus and prefrontal cortex BDNF levels were increased while serum glucose levels and level of lipid peroxidation indicator malondialdehyde in serum and hippocampus were reduced. Our unique results suggest that improved cognition in adult rats with LCD feeding during adolescence may result from the increase of neurogenesis and BDNF. These findings reveal the importance of nutrition in adolescence for cognitive function in adulthood. Our results may be useful for further studies aiming to treat age-related cognitive impairments.

NITRIC OXIDE INVOLVEMENT IN SEIZURES ELICITED BY PENTYLENTETRAZOL AND SEX DEPENDENCE

It has been known that susceptibility to some types of epilepsy is affected by sex. In addition, the role of NO in epileptogenesis is still unclear; NO has been suggested to be either an anticonvulsive or a proconvulsive agent. In an attempt to elucidate both the role of NO and sex differences in sensitivity to seizures, male and female Wistar rats were treated intraperitoneally (i.p.) by pentylentetrazol (PTZ)(80 mg/kg) and by a nitric oxide synthase(NOS) inhibitor N-omega-nitro-L-arginine-mthylester(L-NAME)(50mg/kg) and a NO precursor sodium-nitroprusside(SNP)(2.5mg/kg)- applied 15 min. before PTZ injection. Latency, frequency, severity, and duration of generalized clonic and clonic-tonic convulsions were recorded. Furthermore, alterations in severity, latency, frequency, and duration of convulsions were observed to correlate with NO. Both sexes, injected with PTZ, showed repetitive seizure patterns. Seizures were found to be more severe in females. L-NAME and SNP pretreatment produced paradoxical effects on PTZ-induced seizures in both sexes. L-NAME completely prevented PTZ-induced seizures in male rats, whereas increased severity, frequency, duration, and significantly shortened the latency in female rats. Unexpectedly, SNP increased convulsion severity, frequency, duration, and shortened latencies in male, whereas it decreased convulsion severity, frequency, and duration and prolonged latency in females. These results indicate that endogenous NO is involved in the regulation of convulsive action suggesting a role depending on sex.

Erythropoietin pretreatment suppresses seizures and prevents the increase in inflammatory mediators during pentylenetetrazole-induced generalized seizures

Erythropoietin (EPO) suppresses epileptic seizures, but the mechanism is unclear. The search for novel targets in the therapy of epilepsy has focused recently on brain inflammation since brain inflammation and the associated blood–brain barrier (BBB) damage appears to be an integral part of epilepsy pathophysiology. We examined the effects of EPO on proinflammatory mediators in brain and serum in PTZ-induced generalized seizure model. The inflammation markers (IL-1β, TNF-α, IL-6, IL-10), BBB and neuron damage markers (S100B, Neuron specific enolase; NSE, respectively) in serum and brain of Sprague–Dawley male rats were examined with the ELISA method. Nitric oxide synthase (NOS) isoforms were investigated immunohistochemically in hippocampus. EPO treatment 4 h and 24 h before PTZ administration had diverse effects. EPO treatment 4 h before PTZ administration elongated the seizure latency, decreased the inflammation and damage markers in serum and brain significantly, whereas EPO treatment 24 h before PTZ administration lowered inflammation and damage markers to control levels and decreased the seizure stage. PTZ-induced seizures increased inducible NOS (iNOS) activity and decreased endothelial NOS (eNOS) activity in hippocampus. Both EPO pretreatments reversed these effects. These findings, i.e., decreased iNOS activity and increased eNOS activity by EPO suggest the first time that the favorable effect of EPO pretreatment on inflammatory mediators triggered by PTZ-induced seizures. This can provide further insight into epilepsy treatment and new prophylactic strategies against epilepsy risk.

The effects of atorvastatin on memory deficit and seizure susceptibility in pentylentetrazole-kindled rats

Deficits in memory function have been observed in pentylentetrazole (PTZ)-kindled rats. In the present study we examined the effects of atorvastatin ((3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitor) on PTZ kindling and related memory deficits in rats trained with the passive avoidance test. Subconvulsive PTZ doses rendered a gradual increase in seizure activity. PTZ kindling caused long-term memory to deteriorate. Atorvastatin per se and in PTZ-kindled rats improved learning and memory functions. It also prolonged latency (time to appearance of spike potentials) and diminished the amplitude and frequency of spike potentials, which indicate epileptic discharges. These novel findings suggest that the favorable effect of the atorvastatin on memory deficits provoked by PTZ kindling might be of clinical utility.

Iron(III) and nickel(II) complexes as potential anticancer agents: synthesis, physicochemical and structural properties, cytotoxic activity and DNA interactions

Template reactions of 2-hydroxy-R-benzaldehyde-S-methylisothiosemicarbazones (R = 3-methoxy or 4-hydroxy) with the corresponding aldehydes in the presence of FeCl3 and NiCl2 yielded N1,N4-disalicylidene chelate complexes. The compounds were characterized by means of elemental and spectroscopic methods. The structure of complex 1 was determined by X-ray single crystal diffraction. Crystal data (Mo Kα; 296 K) are as follows: monoclinic space group P21/c, a = 12.9857(8) A, b = 7.8019(4) A, c = 19.1976(12) A, β = 101.655(5)°, Z = 4. Cytotoxic effects of the compounds were evaluated by the MTT assay in K562 leukemia, ECV304 endothelial and normal mononuclear cells, and DNA fragmentation analysis using the diphenylamine reaction was performed. The DNA binding capacity of thiosemicarbazones at IC50 and different concentrations was investigated. The DNA fragmentation percentage of compound treated cells was higher than that of non-treated control cells but was higher for compound 3 (84%) compared to the others. The interaction of compounds 1–4 and DNA was investigated voltammetrically by using nucleic acid modified electrodes after the double stranded fish sperm DNA (fsDNA), or poly(dA)·poly(dT), was immobilized onto the surface of pencil graphite electrodes (PGEs). Accordingly, the oxidation signals of DNA bases, guanine and adenine, were measured by using differential pulse voltammetry (DPV). The changes in the signals of guanine and adenine were evaluated before and after the interaction process. The results indicated that compound 3 was cytotoxic at very low concentrations in K562 leukemia cells unlike other cells and that could damage the DNA double stranded form, specifically the adenine base. Therefore, it may have a selective antileukemic effect and drug potential.

The effects of 17β-estradiol on blood brain barrier integrity in the absence of the estrogen receptor alpha; an in-vitro model

The blood-brain barrier (BBB), which saves the brain from toxic substances, is formed by endothelial cells. It is mainly composed of tight junction (TJ) proteins existing between endothelial cells. Estrogen is an important regulatory hormone of BBB permeability. It protects the BBB before menopause, but may increase BBB permeability with aging. In addition, nitric oxide modulates BBB permeability. Alcohol impairs the integrity of the BBB with oxidants and inflammatory mediators such as iNOS. We investigated the effects of estrogen on BBB integrity in an in vitro BBB model created with ERα-free HUVEC (human umbilical vein endothelial-like cells) to mimics the menopausal period. In vitro BBB model is created with HUVEC/C6 (rat glioma cells) co-culture. The effect of 17β-estradiol on ethanol-induced BBB disruption and change/or increase of iNOS activity, which modulate BBB integrity, were evaluated. Inducibility and functionality of BBB were investigated using transendothelial electrical resistance (TEER) and the expression of proteins TJ proteins (occludin and claudin-1) and iNOS activity by immunostaining. Our results revealed that 17β-estradiol treatment before and after ethanol decrease expression of occludin and claudin-1 and value of TEER which are BBB disrupt indicators. In addition, ethanol and 17β-estradiol separately and pre- and post-ethanol 17β-estradiol treatment increased iNOS expression. Thus our study suggests caution in the use of 17β-estradiol after menopause because 17β-estradiol at this time may both increase the inflammatory process as well as damage the BBB. We think that beneficial effects of 17β-estradiol may be through ERα but it needs further studies.

The evaluation of human tenon's fibroblasts and endothelial cell responses to antifibrotics alone and in combination with α-tocopherol.

Abstract Purpose: We aimed to evaluate the influence of current antifibrotic agents as well as the possible results obtained by combining these agents. This study included α-tocopherol, a strong antifibrotic and an efficient neuromediator of pathways used by other agents. Materials and Methods: Mitochondrial Bcl-2, Bax, cytochrome c and cytoplasmic caspase-3 expression, as well as toxic effect patterns, mitosis and cellular reactions due to α-tocopherol alone or combined with paclitaxel, mitomycin C and 5-flurouracil (5-FU), was studied in series obtained from human endothelial and primary Tenon’s fibroblast cell cultures. Results: The strongest apoptotic effect in both cell groups belonged to paclitaxel, followed by mitomycin C, and despite the overall suppressive effect of the α-tocopherol combination, mitomycin C increased its efficiency on the endothelial cells. The apoptosis/necrosis ratio was highest in α-tocopherol and lowest in paclitaxel, with α-tocopherol generally decreasing necrosis. Bax was observed at a high level with mitomycin C. Cytotoxicity was the highest with paclitaxel, and the caspase-3 reaction was markedly higher with mitomycin C in both cell types. In the α-tocopherol and 5-FU slides, mitosis and a layered formation were observed. The addition of α-tocopherol reduced the cytotoxicity of all antifibrotic agents in both cell series by decreasing the cell numbers, leading to necrosis. Conclusions: Alone or in combination, the use of α-tocopherol and 5-FU is safer than other agents. By suppressing the cytotoxic effects of other antifibrotic agents, α-tocopherol is a promising drug for improving the effects of antifibrotics in many aspects of medicine. In addition, it has the potential to play a role beyond its antioxidant and antifibrotic activity in ocular surgery.

IN VITRO EFFECTS OF GROWTH FACTORS AND INTERFERON-α ON BUSULFAN CYTOTOXICITY

An experimental approach to increasing the effectiveness of leukemia treatment with S-phase-specific cytotoxics is to increase the cycling of leukemia cells with growth factors. However, growth factors may have a different relationship with non-cell-cycle-specific agents. The authors examined the effects of granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), and interferon-α (INF-α) on the cytotoxic effects of the alkylating agent busulfan on the erythro-myeloid cell line K562. G-CSF and GM-CSF increased the proliferation and colony-forming ability of K562 cells and protected the cells from busulfan effects. INF-α decreased the colony-forming ability and proliferation of the K562 cells and demonstrated a possibly additive effect with busulfan. In the cell line K562, the growth factors G-CSF and GM-CSF protected the cells from the non-cell-cycle-specific alkylating agent busulfan, whereas IFN-α demonstrated an additive cytotoxic effect.