Anti-proliferative, pro-apoptotic and anti-invasive effect of the copper coordination compound Cas III-La through the induction of reactive oxygen species and regulation of Wnt/ß-catenin pathway in glioma.

Gliomas are the most aggressive neoplasms that affect the central nervous system, being glioblastoma multiforme (GBM) the most malignant. The resistance of GBM to therapies is attributed to its high rate of cell proliferation, angiogenesis, invasion, and resistance to apoptosis; thus, finding alternative therapeutic approaches is vital. In this work, the anti-proliferative, pro-apoptotic, and anti-invasive effect of the copper coordination compound Casiopeina III-La (Cas III-La) on human U373 MG cells was determined in vitro and in vivo. Our results indicate that Cas III-La exerts an anti-proliferative effect, promoting apoptotic cell death and inactivating the invasive process by generating reactive oxygen species (ROS), inactivating GSK3ß, activating JNK and ERK, and promoting the nuclear accumulation of ß-catenin. The inhibition of ROS generation by N-acetyl-l-cysteine not only recovered cell migration and viability, but also reduced ß-catenin accumulation and JNK and ERK activation. Additionally, Cas III-La significantly reduced tumor volume, cell proliferation and mitotic indices, and increased the apoptotic index in mice xenotransplanted with U373 glioma cells. Thus, Cas III-La is a promising agent to treat GBM.

Autophagy as a Potential Therapy for Malignant Glioma.

Glioma is the most frequent and aggressive type of brain neoplasm, being anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM), its most malignant forms. The survival rate in patients with these neoplasms is 15 months after diagnosis, despite a diversity of treatments, including surgery, radiation, chemotherapy, and immunotherapy. The resistance of GBM to various therapies is due to a highly mutated genome; these genetic changes induce a de-regulation of several signaling pathways and result in higher cell proliferation rates, angiogenesis, invasion, and a marked resistance to apoptosis; this latter trait is a hallmark of highly invasive tumor cells, such as glioma cells. Due to a defective apoptosis in gliomas, induced autophagic death can be an alternative to remove tumor cells. Paradoxically, however, autophagy in cancer can promote either a cell death or survival. Modulating the autophagic pathway as a death mechanism for cancer cells has prompted the use of both inhibitors and autophagy inducers. The autophagic process, either as a cancer suppressing or inducing mechanism in high-grade gliomas is discussed in this review, along with therapeutic approaches to inhibit or induce autophagy in pre-clinical and clinical studies, aiming to increase the efficiency of conventional treatments to remove glioma neoplastic cells.

Autophagic and Apoptotic Pathways as Targets for Chemotherapy in Glioblastoma.

Glioblastoma multiforme is the most malignant and aggressive type of brain tumor, with a mean life expectancy of less than 15 months. This is due in part to the high resistance to apoptosis and moderate resistant to autophagic cell death in glioblastoma cells, and to the poor therapeutic response to conventional therapies. Autophagic cell death represents an alternative mechanism to overcome the resistance of glioblastoma to pro-apoptosis-related therapies. Nevertheless, apoptosis induction plays a major conceptual role in several experimental studies to develop novel therapies against brain tumors. In this review, we outline the different components of the apoptotic and autophagic pathways and explore the mechanisms of resistance to these cell death pathways in glioblastoma cells. Finally, we discuss drugs with clinical and preclinical use that interfere with the mechanisms of survival, proliferation, angiogenesis, migration, invasion, and cell death of malignant cells, favoring the induction of apoptosis and autophagy, or the inhibition of the latter leading to cell death, as well as their therapeutic potential in glioma, and examine new perspectives in this promising research field.

Piqueria trinervia as a source of metabolites against Giardia intestinalis.

CONTEXT: Piqueria trinervia Cav. (Asteraceae) is a plant species with a long history in traditional medicine to cure diarrhoea and other digestive disorders. OBJECTIVE: The study investigates the antigiardial activity of piquerol, trinervinol, red oil and two fractions (F1 and F2) from P. trinervia. MATERIALS AND METHODS: P. trinervia was collected in the Ajusco in Mexico City. Aerial parts were ground and mixed with water to obtain the extract, which was treated with dichloromethane to isolate piquerol and trinervinol (P & T). Remnants were the red oil, fractions 1 and 2 (RO, F1 & F2). Trophozoites of Giardia intestinalis were treated with P, T, RO, F1 and F2 at different concentrations (0.78-200 µg/mL) for 48 h. Antigiardial activity was measured using the methylene blue reduction, and the cytotoxicity assayed on human fibroblasts and Vero cells by reduction of tetrazolium salts. RESULTS: Trinervinol and piquerol showed antigiardial activity with an IC50 = 2.03 and 2.42 µg/mL, and IC90 = 13.03 and 8.74 µg/mL, respectively. The concentrations of trinervinol (CC50 = 590 µg/mL) and piquerol (CC50 = 501 µg/mL) were not cytotoxic to human fibroblasts. CONCLUSIONS: Compounds from P. trinervia showed antigiardial activity; to enhance this activity, piquerol and trinervinol can be chemically modified.

In vitro evaluation of apoptotic effect of bis(acetylacetonato-k2 O,O')(1,10-phenanthroline-k2 N,N')Zn(II) complex.

Phenanthroline derivatives have been reported as potential bioactive compounds because of their ability to interact with DNA. To evaluate the antiproliferative effect of bis(acetylacetonate-k2 O,O)(1,10-phenanthroline-k2 N,N)Zn(II) or Zn(acac)2 (phen) complex, the compound was obtained in a simple manner and further characterized to determine crystal structure, thermal behavior, morphology, and spectroscopic properties. The structure of the complex was confirmed by X-ray single structure as well as by 1H and 13C nuclear magnetic resonance (NMR) in dmso-d6 (dimethyl sulfoxide) solution and in the solid state by 13C CP/MAS. Although preparation of this compound has been described previously, there are no reports on its biological activity; here, we assessed its antiproliferative effect on fibroblasts, A253, FaDu, Cal-27, RH-30, RD, U-373, C6, A-549, MDA-MB-231, and MCF-7 cancer cell lines at different doses (50-100 and 150 µg/ml). The cell viability was determined by MTT assay and high activity was observed for the most of the cell lines, and TUNEL results showed the induction of apoptosis.

Neuroprotective effect of thalidomide on MPTP-induced toxicity.

Thalidomide is a sedative with unique pharmacological properties; studies on epilepsy and brain ischemia have shown intense neuroprotective effects. We analyzed the effect of thalidomide treatment on the neurotoxicity caused by the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahidropyridine (MPTP) in mice. Thalidomide was administered at two times; before and after the exposure to MPTP. In both circumstances thalidomide improved the neurotoxicity induced by MPTP as seen by a significant raise of the striatal contents of dopamine and simultaneous decrease of monoamine-oxidase-B (MAO-B). These results indicate that in the experimental model of Parkinson's disease the administration of thalidomide improves the functional damage on the nigrostriatal cell substratum as seen by the production of dopamine. This neuroprotective effect seems to be mediated by inhibition of excitotoxicity. Our results suggest that thalidomide could be investigated as potential adjuvant therapy for Parkinson's disease.

Anti-apoptotic, anti-oxidant, and anti-inflammatory effects of thalidomide on cerebral ischemia/reperfusion injury in rats.

Thalidomide has shown protective effects in different models of ischemia/reperfusion damage. To elucidate the mechanisms of such protection, this study assessed the effects of thalidomide on the oxidative stress and inflammatory response induced by ischemia/reperfusion episodes in rats. Rats underwent middle cerebral artery occlusion (MCAO) for 2hours. All animals were sacrificed after different reperfusion times. Rats were administered either DMSO or thalidomide (20mg/kg (i.p.)) at different times before or during reperfusion: 1) 1h before reperfusion; the infarct area was measured 2h after reperfusion. 2) 10min before reperfusion and 80min after reperfusion; the infarct area was measured 24h after reperfusion; and 3) 10min before reperfusion and 1h, 24h, 48h, and 68h after reperfusion; the infarct area was measured 72h after reperfusion. Thalidomide reduced the infarct area 24h and 72h after MCAO, and decreased the neurological deficit in all groups with respect to controls. Thalidomide also lowered significantly the number of TUNEL-positive cells, levels of Bax, caspase-3, lipoperoxidation, and pro-inflammatory cytokines, and increased the levels of SOD1, Bcl-2 and pAkt. These results show that thalidomide has neuroprotective effects, apparently due to its anti-apoptotic, anti-oxidant, and anti-inflammatory effects.

Retinoic acid reduces solvent-induced neuropathy and promotes neural regeneration in mice.

In humans, exposure to organic solvents (OS) is frequent in work activities or as a recreational inhalant, inducing severe neuropathy (secondary to demyelization of peripheral nerves). We have previously shown that all-trans retinoic acid (ATRA) increases local content of neural growth factor (NGF), improving peripheral neuropathy of diverse origins. In this study, we evaluated the effect of ATRA on OS-induced peripheral neuropathy in experimental mice. Two simultaneous experiments were performed. The first one aimed to evaluate ATRA for the prevention of damage induced by OS, the second to test ATRA as an OS-induced neuropathy treatment. Nociceptive threshold latency and NGF concentration in serum and in peripheral nerves were determined. Morphological changes and evidence of sciatic nerve regeneration were evaluated. Mice exposed to OS developed neuropathy and axonal degeneration. ATRA diminished the effects of OS inhalation on sensorial changes and nerve morphology. Treatment with ATRA reversed sensorial and nerve morphological changes of OS-induced neuropathy, and this was associated with increased contents of NGF. Similar to previous experiences on diabetic and toxic neuropathy, ATRA reduced and partially reversed the peripheral neuropathy caused by OS exposure. These favorable effects apparently are due to local production of NGF induced by neural regeneration in response to the administration of retinoic acid.

Strong anticonvulsant effect of thalidomide on amygdaloid kindling.

Thalidomide was synthesized more than 50 years ago as hypnotic sedative with unique pharmacologic properties. Recently, we have described a notorious anticonvulsant effect of thalidomide on pentylenetetrazole-induced seizures. Here, we report the results of thalidomide administration on amygdaloid kindling. A total of 100 male Wistar rats were implanted with brain electrodes in the basolateral amygdaloid nucleus and the sensory motor cortex. After surgery the animals received a daily electric stimulus through the amygdaline electrode (500 µA intensity, 60 Hz frequency, 1 ms duration) until seizures appeared. The following treatment groups were made: (a) controls; (b) rats treated daily with thalidomide (10 mg/kg) or with topiramate (80 mg/kg); (c) rats treated with different doses of thalidomide. Significant reduction in the after-discharge and retard of behavioral stages were observed in rats treated with thalidomide or with topiramate as compared with controls (p<0.01): Also, a similar anticonvulsant outcome of thalidomide therapy was obtained with doses of either 2.5, 5, 10 or 50 mg/kg; at 100 mg/kg all epileptic activity was suppressed. Anticonvulsant efficacy of thalidomide was superior in most parameters than that obtained with topiramate. In amygdaloid kindling, which simulates human epilepsy characterized by focal seizures secondarily generalized, low doses of thalidomide display strong anticonvulsant properties.

Thalidomide for treatment of refractory epilepsy.

We have experimentally shown that thalidomide has strong anticonvulsant properties. In an open label study, eight male patients with refractory epilepsy received thalidomide at daily-doses of 200 mg during 1 year, frequency of seizures before and during treatment were compared. The mean number of seizures before thalidomide administration was 26 ± 4 per month; it decreased to 7 ± 1 along thalidomide therapy. Our results indicate that thalidomide has strong therapeutic effects in refractory epilepsy.

Thalidomide inhibits pentylenetetrazole-induced seizures.

Thalidomide was originally synthesized and tested as a sedative, hypnotic and antiemetic; however, after its teratogenicity was noted its use for treatment of neurological and psychiatric disorders was abandoned. We studied the potential anticonvulsant effect of thalidomide: Different doses of thalidomide were tested against seizures induced by 50 mg/kg or 70 mg/kg of pentylenetetrazole (PTZ); the anticonvulsant effect of thalidomide was also compared with that of valproic acid. Seizures and latency time were individually recorded. Thalidomide in low doses (5-10 mg/kg) prevented seizures in all animals treated with 50 mg/kg PTZ; also, in a dose-dependent manner thalidomide inhibited seizures in rats exposed to a high dose of PTZ (70 mg/kg); thalidomide exhibited an anticonvulsant activity similar to that of valproic acid. Thalidomide is an effective anticonvulsant, and further studies on this potential antiepileptic substance seem warranted.

Efficacy of nitazoxanide, tizoxanide and tizoxanide/albendazole sulphoxide combination against Taenia crassiceps cysts.

OBJECTIVES: Neurocysticercosis is a common parasitic disease in the CNS in humans caused by the metacestode Taenia solium, with high incidence in developing countries. Albendazole is the drug of choice. However, a wide interindividual variability in the response has been reported. In order to evaluate alternative treatment options, the in vitro efficacy of nitazoxanide, its main metabolite tizoxanide as well as the tizoxanide and albendazole sulphoxide combination was tested against Taenia crassiceps cysts. METHODS: T. crassiceps cysts were incubated in culture medium containing different concentrations of nitazoxanide, tizoxanide and albendazole sulphoxide (0.037-0.42 microg/mL). The effect of the tizoxanide and albendazole sulphoxide combination was evaluated in a fixed-concentration ratio (1:1). Isobolographic analyses were used to define the kind of interaction between drugs. Morphological and ultrastructural alterations over the parasite tissue were observed by light and transmission electron microscopy. RESULTS: Nitazoxanide and tizoxanide exhibited cestocidal activity which was time-concentration-dependent. The EC(50) values were 0.15, 0.12 and 0.080 microg/mL for nitazoxanide, tizoxanide and albendazole sulphoxide, respectively. No statistical differences between EC(50) values were found, indicating that nitazoxanide and tizoxanide are equally potent as albendazole sulphoxide. The effect of the tizoxanide and albendazole sulphoxide combination was faster than that observed with each drug alone. Isobolographic analysis showed that the effect of the combination was additive. Nitazoxanide and tizoxanide had an effect on the germinal layer, where lipid droplets were found. Nitazoxanide and tizoxanide produced less damage than albendazole sulphoxide on the germinal layer. After the tizoxanide and albendazole sulphoxide combination, a high accumulation of lipid droplets within the germinal layer of the parasite was found. CONCLUSIONS: Our results suggest that nitazoxanide in combination with albendazole could be useful for treatment of cysticercosis infections. Additional in vivo studies are required to confirm this hypothesis.

Evaluation of the efficacy of albendazole sulphoxide and praziquantel in combination on Taenia crassiceps cysts: in vitro studies.

OBJECTIVES: Praziquantel and albendazole are currently used for chemotherapeutic treatment of neurocysticercosis. Albendazole has been found to be more effective than praziquantel; however, it is well known that not all patients will show a complete resolution of cysts. Searching for more effective treatments, this study was designed to evaluate the effect of the combination of praziquantel and albendazole sulphoxide in a Taenia crassiceps in vitro model as well as the kind of interaction between both drugs. METHODS: In order to determine the concentration that produced 50% effect (EC50), T. crassiceps cysts were incubated in culture medium containing praziquantel (0.005-0.04 microg/mL), albendazole sulphoxide (0.021-0.16 microg/mL) or the combination of praziquantel and albendazole sulphoxide in a fixed-dose ratio (1:1). The experimental concentration (EC50Exp) of the combination was determined from the concentration-response curve constructed from the combined drug treatment. Isobolographic analyses were used to define the nature of the interaction between praziquantel and albendazole sulphoxide. Morphological and ultrastuctural alterations after different treatments over the parasite tissue were observed by light and transmission electron microscopy. RESULTS: The changes in ultrastructure were more marked with the praziquantel and albendazole sulphoxide combination. Also the cysticidal effect of the combination was observed earlier than that of each drug alone. When isobolographic analysis was employed, we found that the experimental EC50 value (0.042 microg/mL) was not significantly different from the theoretical EC50 value (0.035 microg/mL), which indicates an additive interaction between praziquantel and albendazole sulphoxide. CONCLUSIONS: Our study suggests that the combination of praziquantel and albendazole sulphoxide could potentially improve the current neurocysticercosis treatment.

Prolonged exposure to lead lowers the threshold of pentylenetetrazole-induced seizures in rats.

PURPOSE: The aim of this work was to study the effects of prolonged exposure to lead on the threshold of experimental seizures induced by pentylenetetrazole (PTZ). METHODS: The 120 Wistar male rats were allocated randomly into four groups; (A) controls, and lead-treatment groups (B, C, and D) that received lead acetate in the drinking water for a period of 30 days at concentrations of 250, 500, and 1,000 ppm, respectively. After exposure, a trial of PTZ-induced seizures was conducted in all groups, and blood contents of lead were determined by atomic absorption spectrophotometry. RESULTS: Blood lead contents increased in a dose-dependent manner. Time elapsed to develop the first myoclonic jerk and the tonic-clonic seizure was less in all lead-exposed groups than in controls. This effect was greater in the groups administered 500 and 1,000 ppm of lead. The required doses of PTZ to induce myoclonic jerks and tonic-clonic seizures were lower in lead-exposed rats than in controls. CONCLUSIONS: We found a reduction in the threshold for seizures in rats whose blood contents of lead were similar to those of humans from some areas of urban centers with high levels of air pollution.

Cas IIgly induces apoptosis in glioma C6 cells in vitro and in vivo through caspase-dependent and caspase-independent mechanisms.

In this work, we investigated the effects of Casiopeina II-gly (Cas IIgly)--a new copper compound exhibiting antineoplastic activity--on glioma C6 cells under both in vitro and in vivo conditions, as an approach to identify potential therapeutic agents against malignant glioma. The exposure of C6 cells to Cas IIgly significantly inhibited cell proliferation, increased reactive oxygen species (ROS) formation, and induced apoptosis in a dose-dependent manner. In cultured C6 cells, Cas IIgly caused mitochondrio-nuclear translocation of apoptosis induction factor (AIF) and endonuclease G at all concentrations tested; in contrast, fragmentation of nucleosomal DNA, cytochrome c release, and caspase-3 activation were observed at high concentrations. Administration of N-acetyl-L-cystein, an antioxidant, resulted in significant inhibition of AIF translocation, nucleosomal DNA fragmentation, and caspase-3 activation induced by Cas IIgly. These results suggest that caspase-dependent and caspase-independent pathways both participate in apoptotic events elicited by Cas IIgly. ROS formation induced by Cas IIgly might also be involved in the mitochondrio-nuclear translocation of AIF and apoptosis. In addition, treatment of glioma C6-positive rats with Cas IIgly reduced tumor volume and mitotic and cell proliferation indexes, and increased apoptotic index. Our findings support the use of Cas IIgly for the treatment of malignant gliomas.

In vitro effects of albendazole sulfoxide and praziquantel against Taenia solium and Taenia crassiceps cysts.

We investigated the minimum exposure times of prazicuantel (PZQ) and albendazole sulfoxide (ABZSO) required for their activities against Taenia cysts in vitro as well as the 50 and 99% effective concentrations. The results showed that although the effects of both drugs are time and concentration dependent, ABZSO acts much slower and is less potent than PZQ.

Effect of thalidomide in different tumors in rodents.

This study investigated the effects of chronic administration of thalidomide on three different neoplasms of ectodermic origin in rodents: 1) chemically induced tumors of the nervous system of rats by transplacental exposure to ethylnitrosourea; 2) transplanted RPMI-1846 melanoma in hamsters and 3) transplanted C6 glioblastoma in rats. No effects were seen on thalidomide-treated rats on the frequency- and time of tumor development induced by ethylnitrosourea. In contrast, a reduction in tumoral growth and mitotic-index was obtained in animals treated with thalidomide in transplanted tumors, melanoma and glioblastoma, when compared with controls (P < 0.001 and 0.025, respectively). These results suggest that, although thalidomide is not a cytotoxic drug for neoplastic cells, it might partially inhibit the tumoral growth through any of its pharmacological actions; by blockage of cell-surface adhesion receptors induction of DNA oxidation, or inhibition of angiogenesis. Further investigations on the use of thalidomide perhaps associated to cytotoxic drugs, for treatment of ectodermic neoplasms seem guaranteed.