Growth inhibitory effects of the Diruthenium-Ibuprofen compound, [Ru2Cl(Ibp) 4], in human glioma cells in vitro and in the rat C6 orthotopic glioma in vivo.

The Diruthenium-Ibuprofen compound [Ru2Cl(Ibp)4] (or RuIbp) is known to cause significant inhibition of C6 rat glioma cell proliferation in vitro. RuIbp increased the expression of cell cycle-related proteins such as p21 and p27 and the pro-apoptotic protein Bax, as well as causing a reduction in mitochondrial membrane potential and a modest increase in apoptosis in vitro. The present study extended these findings by (i) investigating the effects of RuIbp on human glioma cell line proliferation in vitro and (ii) investigating the acute and chronic toxicology of the compound in normal Wistar rats. The compound was then tested for its anti-tumour properties by either chronic 14 days intra-peritoneal (IP) administration or chronic Alzet osmotic pump infusion, in the rat C6 orthotopic glioma model in vivo. The IP injection of RuIbp caused a 41 % inhibition of tumour area without significant toxic effects but with an increase in blood neutrophils and monocytes and a decrease in blood lymphocytes. In an attempt to reduce this effect RuIbp was administered by Alzet osmotic pump infusion directly into the tumour at a dose of 15 mg/kg with an infusion rate of 0.5 µL/h for 14 days. The direct infusion of RuIbp caused a 45 % inhibition of tumour area without alterations in differential blood leukocyte counts. These results prove the efficacy of RuIbp in human glioma cell lines in vitro and in an in vivo glioma model and point to its potential as an inhibitor of tumour growth in vivo.

The novel ruthenium-gamma-linolenic complex [Ru(2)(aGLA)(4)Cl] inhibits C6 rat glioma cell proliferation and induces changes in mitochondrial membrane potential, increased reactive oxygen species generation and apoptosis in vitro.

The present study reports the synthesis of a novel compound with the formula [Ru(2)(aGLA)4Cl] according to elemental analyses data, referred to as Ru(2)GLA. The electronic spectra of Ru(2)GLA is typical of a mixed valent diruthenium(II,III) carboxylate. Ru(2)GLA was synthesized with the aim of combining and possibly improving the anti-tumour properties of the two active components ruthenium and gamma-linolenic acid (GLA). The properties of Ru(2)GLA were tested in C6 rat glioma cells by analysing cell number, viability, lipid droplet formation, apoptosis, cell cycle distribution, mitochondrial membrane potential and reactive oxygen species. Ru(2)GLA inhibited cell proliferation in a time and concentration dependent manner. Nile Red staining suggested that Ru(2)GLA enters the cells and ICP-AES elemental analysis found an increase in ruthenium from <0.02 to 425 mg/Kg in treated cells. The sub-G1 apoptotic cell population was increased by Ru(2)GLA (22 +/- 5.2%) when analysed by FACS and this was confirmed by Hoechst staining of nuclei. Mitochondrial membrane potential was decreased in the presence of Ru(2)GLA (44 +/- 2.3%). In contrast, the cells which maintained a high mitochondrial membrane potential had an increase (18 +/- 1.5%) in reactive oxygen species generation. Both decreased mitochondrial membrane potential and increased reactive oxygen species generation may be involved in triggering apoptosis in Ru(2)GLA exposed cells. The EC(50) for Ru(2)GLA decreased with increasing time of exposure from 285 microM at 24 h, 211 microM at 48 h to 81 microM at 72 h. In conclusion, Ru(2)GLA is a novel drug with antiproliferative properties in C6 glioma cells and is a potential candidate for novel therapies in gliomas.

Gamma-linolenic acid alters Ku80, E2F1, and bax expression and induces micronucleus formation in C6 glioma cells in vitro.

Gamma-linolenic acid (GLA) is an inhibitor of tumor cell proliferation in both in vitro and in vivo conditions. The aim of this study was to investigate the effects of 150 muM GLA on the expression of E2F1, cyclin D1, bax, bcl2, Ku70, and Ku80 in C6 rat glioma cells. The Ku proteins were chosen as previous studies have shown that loss or reduction in their expression causes increased DNA damage and micronucleus formation in the presence of radiation. The fact that GLA exposure is known to enhance the efficacy of radiation treatment raised the question whether the Ku proteins could be involved in this effect as seen for other molecules such as roscovitine and flavopiridol. GLA altered the mRNA expression of E2F1, cyclin D1, and bax, but no changes were found for bcl2, Ku70, and Ku80. Alterations in protein expression were observed for bax, Ku80, and E2F1. The 45% decrease in E2F1 expression was proportional to decreased cell proliferation (44%). Morphological analysis found a 25% decrease in mitotic activity in the GLA-treated cells, which was accompanied by a 49% decrease in S-phase by FACS analysis. A 39% increase in the number of micronuclei detected by Hoechst fluorescence points to GLA's effects on cell division even at concentrations that do not produce significant increases in apoptosis. Most important was the finding that Ku80 expression, a critical protein involved in DNA repair as a heterodimer with Ku70, was decreased by 71%. It is probable that reduced Ku80 is responsible for the increase in micronucleus formation in GLA-treated cells in a similar manner to that found in Ku80 null cells exposed to radiation. The decreased expression of Ku80 and E2F1 could make cells more susceptible to radiotherapy and chemotherapy.

Gamma-linolenic acid inhibits both tumour cell cycle progression and angiogenesis in the orthotopic C6 glioma model through changes in VEGF, Flt1, ERK1/2, MMP2, cyclin D1, pRb, p53 and p27 protein expression.

BACKGROUND: Gamma-linolenic acid is a known inhibitor of tumour cell proliferation and migration in both in vitro and in vivo conditions. The aim of the present study was to determine the mechanisms by which gamma-linolenic acid (GLA) osmotic pump infusion alters glioma cell proliferation, and whether it affects cell cycle control and angiogenesis in the C6 glioma in vivo. METHODS: Established C6 rat gliomas were treated for 14 days with 5 mM GLA in CSF or CSF alone. Tumour size was estimated, microvessel density (MVD) counted and protein and mRNA expression measured by immunohistochemistry, western blotting and RT-PCR. RESULTS: GLA caused a significant decrease in tumour size (75 +/- 8.8%) and reduced MVD by 44 +/- 5.4%. These changes were associated with reduced expression of vascular endothelial growth factor (VEGF) (71 +/- 16%) and the VEGF receptor Flt1 (57 +/- 5.8%) but not Flk1. Expression of ERK1/2 was also reduced by 27 +/- 7.7% and 31 +/- 8.7% respectively. mRNA expression of matrix metalloproteinase-2 (MMP2) was reduced by 35 +/- 6.8% and zymography showed MMP2 proteolytic activity was reduced by 32 +/- 8.5%. GLA altered the expression of several proteins involved in cell cycle control. pRb protein expression was decreased (62 +/- 18%) while E2F1 remained unchanged. Cyclin D1 protein expression was increased by 42 +/- 12% in the presence of GLA. The cyclin dependent kinase inhibitors p21 and p27 responded differently to GLA, p27 expression was increased (27 +/- 7.3%) while p21 remained unchanged. The expression of p53 was increased (44 +/- 16%) by GLA. Finally, the BrdU incorporation studies found a significant inhibition (32 +/- 11%) of BrdU incorporation into the tumour in vivo. CONCLUSION: Overall the findings reported in the present study lend further support to the potential of GLA as an inhibitor of glioma cell proliferation in vivo and show it has direct effects upon cell cycle control and angiogenesis. These effects involve changes in protein expression of VEGF, Flt1, ERK1, ERK2, MMP2, Cyclin D1, pRb, p53 and p27. Combination therapy using drugs with other, complementary targets and GLA could lead to gains in treatment efficacy in this notoriously difficult to treat tumour.

Bioaccessibility of Shore Magic® collagen, a low-molecular-weight collagen supplement, in different in vitro barrier models.

Hydrolyzed collagen consists of peptides, which exert important biological functions in different body systems. This study aimed at testing the biological effects of a low molecular weight collagen (LMWC), namely Shore Magic® Collagen (SMC), in a series of in vitro assays and three different in vitro barrier models with translational significance. We also compared SMC's biological activities with its trypsinized form (TSMC). SMC enhanced migration in both epithelial and endothelial cells; and increased the adhesion of epithelial cells, but surprisingly not of endothelial cells. It also diminished the tightness in the gut and blood-brain barriers in vitro while TSMC did not. SMC induced both neurogenesis and BJ epithelial cell proliferation of cells growing below the in vitro barriers. In conclusion, the intact form of SMC shows enhanced bioavailability and efficiency compared with TSMC.

Importance of ABC Transporters in Drug Development.

ATP-binding cassette (ABC) transporters are a huge family of ATP-dependent transmembrane proteins whose main function is exporting or importing substances or molecules through the cell membranes, plasma cell membrane, or inner membranes in organelles. They fulfill these functions by maintaining cell integrity, metabolism, and homeostasis. They are expressed in a variety of tissues as they transport numerous essential compounds including lipids and other signaling molecules. ABC transporters became widely studied since the discovery of their ability to carry a multitude of xenobiotics, including therapeutic drugs, and in light of the fact that they represent a hurdle for the treatment of resistant cancers. In contrast, the role of ABC transporters in neurological diseases like Alzheimer`s and Parkinson`s, depression, schizophrenia, and epilepsy remains controversial and their mechanism of action in these pathologies remains elusive, thus hindering the implementation of therapies aimed at modulating the functions of these transporters. To date, a number of natural and synthetic compounds are known to act as inhibitors, substrates, and even inducers of these transporters, being able to modulate their expression and/or function; however, their implication as therapeutic agents is far from reaching wide clinical utilization. This review highlights the importance of overcoming the challenges posed by ABC transporters in drug development.

(11)C- and (18)F-Labeled Radioligands for P-Glycoprotein Imaging by Positron Emission Tomography.

P-Glycoprotein (P-gp) is an efflux transporter widely expressed at the human blood-brain barrier. It is involved in xenobiotics efflux and in onset and progression of neurodegenerative disorders. For these reasons, there is great interest in the assessment of P-gp expression and function by noninvasive techniques such as positron emission tomography (PET). Three radiolabeled aryloxazole derivatives: 2-[2-(2-methyl-((11)C)-5-methoxyphenyl)oxazol-4-ylmethyl]-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline ([(11)C]-5); 2-[2-(2-fluoromethyl-((18)F)-5-methoxyphenyl)oxazol-4-ylmethyl]-6,7-dimethoxy-1,2,3,4-tetra-hydroisoquinoline ([(18)F]-6); and 2-[2-(2-fluoroethyl-((18)F)-5-methoxyphenyl)oxazol-4-ylmethyl]-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline ([(18)F]-7), were tested in several in vitro biological assays to assess the effect of the aryl substituent in terms of potency and mechanism of action toward P-gp. Methyl derivative [(11)C]-5 is a potent P-gp substrate, whereas the corresponding fluoroethyl derivative [(18)F]-7 is a P-gp inhibitor. Fluoromethyl compound [(18)F]-6 is classified as a non-transported P-gp substrate, because its efflux increases after cyclosporine A modulation. These studies revealed a promising substrate and inhibitor, [(11)C]-5 and [(18)F]-7, respectively, for in vivo imaging of P-gp by using PET.

Novel ruthenium - gamma-linolenic acid complex inhibits C6 rat glioma cell proliferation in vitro and in the orthotopic C6 model in vivo after osmotic pump infusion.

AIM: Gliomas are primary brain tumours. Gamma-linolenic acid (GLA) exerts anti-proliferative effects. Several ruthenium-containing complexes have antiproliferative effects and can be used as adjuvant therapies in cisplatin-resistant cancer. The present study reports on the anti-proliferative properties and effects on tumour morphology of a novel diruthenium-GLA complex (Ru2GLA) and its comparison with GLA in the C6 rat glioma model both in vitro and in vivo. MATERIALS AND METHODS: In vitro and in vivo experiments were performed on C6 glioma rat cells, and in an orthotopic model. RESULTS: Ru2GLA (100 µM) appears to be an inhibitor of C6 rat glioma cell proliferation. The nuclear area of Ru2GLA-treated cells was 2.18-times larger than that of control cells, suggesting DNA replication occurred but mitosis was blocked in the G2-M phase. Ru2GLA (2 mM) inhibited C6 cell proliferation in vivo and the changes in tumor morphology confirm both cellular uptake and collagen fibre-binding in the extracellular matrix. CONCLUSION: Ru2GLA appears to be a low-toxicity drug and a potential candidate for anti-proliferative therapy of glioma.

New perspectives in nuclear neurology for the evaluation of Parkinson's disease.

The pathophysiology of Parkinson's disease (PD) has not yet been completely elucidated. However, during the past few years, significant progress has been made in understanding the intra- and extracellular mechanisms by which proteins such as alpha-synuclein and neuroinflammatory molecules may display impaired function and/or expression in PD. Recent developments in imaging techniques based on positron emission tomography (PET) and single photon emission computed tomography (SPECT) now allow the non-invasive tracking of such molecular targets of known relevance to PD in vivo. This article summarizes recent PET and SPECT studies of new radiopharmaceuticals and discusses their potential role and perspectives for use in the fields of new drug development and early diagnosis for PD, as well to aid in differential diagnosis and monitoring of the progression of PD.

New molecular targets for PET and SPECT imaging in neurodegenerative diseases.

The pathophysiology of neurodegenerative diseases (ND) such as Alzheimer's disease (AD) and Parkinson's disease (PD) has not yet been completely elucidated. However, in the past few years, there have been great knowledge advances about intra-and extracellular proteins that may display impaired function or expression in AD, PD and other ND, such as amyloid beta (Aß), α-synuclein, tau protein and neuroinflammatory markers. Recent developments in the imaging techniques of positron emission tomography (PET) and single photon emission computed tomography (SPECT) now allow the non-invasive tracking of such molecular targets of known relevance to ND in vivo. This article summarizes recent findings of PET and SPECT studies using these novel methods, and discusses their potential role in the field of drug development for ND as well as future clinical applications in regard to differential diagnosis of ND and monitoring of disease progression.

Inhibition of C6 rat glioma proliferation by [Ru2Cl(Ibp)4] depends on changes in p21, p27, Bax/Bcl2 ratio and mitochondrial membrane potential.

The ruthenium compound [Ru(2)Cl(Ibp)(4)] (or RuIbp) has been reported to cause significantly greater inhibition of C6 glioma cell proliferation than the parent HIbp. The present study determined the effects of 0-72h exposure to RuIbp upon C6 cell cycle distribution, mitochondrial membrane potential, reactive species generation and mRNA and protein expression of E2F1, cyclin D1, c-myc, pRb, p21, p27, p53, Ku70, Ku80, Bax, Bcl2, cyclooxygenase 1 and 2 (COX1 and COX2). The most significant changes in mRNA and protein expression were seen for the cyclin-dependent kinase inhibitors p21 and p27 which were both increased (p<0.05). The marked decrease in mitochondrial membrane potential (p<0.01) and modest increase in apoptosis was accompanied by a decrease in anti-apoptotic Bcl2 expression and an increase in pro-apoptotic Bax expression (p<0.05). Interestingly, COX1 expression was increased in response to a significant loss of prostaglandin E(2) production (p<0.001), most likely due to the intracellular action of Ibp. Future studies will investigate the efficacy of this novel ruthenium-ibuprofen complex in human glioma cell lines in vitro and both rat and human glioma cells growing under orthotopic conditions in vivo.

New molecular targets for PET and SPECT imaging in neurodegenerative diseases / Novos alvos moleculares para tomografia por emissão de pósitrons (PET) e tomografia computadorizada por emissão de fóton único (SPECT) em doenças neurodegenerativas

The pathophysiology of neurodegenerative diseases (ND) such as Alzheimer's disease (AD) and Parkinson's disease (PD) has not yet been completely elucidated. However, in the past few years, there have been great knowledge advances about intra-and extracellular proteins that may display impaired function or expression in AD, PD and other ND, such as amyloid beta (Aβ), α-synuclein, tau protein and neuroinflammatory markers. Recent developments in the imaging techniques of positron emission tomography (PET) and single photon emission computed tomography (SPECT) now allow the non-invasive tracking of such molecular targets of known relevance to ND in vivo. This article summarizes recent findings of PET and SPECT studies using these novel methods, and discusses their potential role in the field of drug development for ND as well as future clinical applications in regard to differential diagnosis of ND and monitoring of disease progression.

A fisiopatologia das doenças neurodegenerativas (DN), tais como a doença de Alzheimer (DA) e a doença de Parkinson (DP), ainda não é completamente compreendida. No entanto, nos últimos anos, houve grandes avanços em termos do conhecimento sobre proteínas intra e extracelulares, tais como beta-amiloide (Aβ), α-sinucleína, proteína tau e marcadores neuroinflamatórios, que podem ter sua função ou expressão prejudicada na DA, DP ou em outras DN. Progressos recentes nas técnicas de tomografia por emissão de pósitrons (PET) e tomografia computadorizada por emissão de fóton único (SPECT) permitem hoje em dia a identificação não invasiva de tais alvos moleculares in vivo. Este artigo resume descobertas recentes de estudos de PET e SPECT cerebral usando esses alvos moleculares inovadores e discute o papel potencial dessas técnicas no campo do desenvolvimento de novos medicamentos para as DN, bem como futuras aplicações clínicas em relação ao diagnóstico diferencial e monitoramento da progressão dessas doenças.