Aluminium oxide nanoparticles induce structural changes in tau and cytotoxicity of the neuroblastoma cell line.

The application of nanomaterials in the healthy system may induce some neurodegenerative diseases initiated by tau folding and neuronal cell death. Herein, aluminium oxide nanoparticles (Al2O3 NPs) were synthesized and characterized by XRD, TEM, DLS and zeta potential investigations. Afterwards, the interaction of Al2O3 NPs with tau protein was investigated by fluorescence and CD spectroscopic methods. The molecular docking and molecular dynamic were also run to explore the binding site and conformational changes of tau after interaction with Al2O3 cluster. Moreover, the MTT, LDH, caspase-9/-3 and flow cytometry assays were done to explore the Al2O3 NPs-induced cytotoxicity against SH-SY5Y cells. It was revealed that Al2O3 NPs bind to tau protein and form a static complex and fold the structure of tau toward a more packed structure. Molecular docking and molecular dynamic investigations revealed that NPs bind to the hydrophilic residues of the tau segments and promote some marginal structural folding of tau segment. The cellular assays displayed that Al2O3 NPs can elicit cell mortality through membrane leakage, caspase-9/-3 activations, and induction of both apoptosis and necrosis. This data may indicate that NPs can induce some adverse effects on the biological systems.

Refractory diarrhea: A paraneoplastic syndrome of neuroblastoma.

Neuroblastoma (NB) is the most common extracranial solid tumor in children. Diarrheal NB is quite rare and is not easy to diagnose in the early stage. Six cases of diarrheal NB in our hospital treated from 1996 to 2006 were retrospectively analyzed, including characteristics such as electrolyte imbalance, pathologic features, vasoactive intestinal peptide (VIP) immunohistochemical staining results, treatment, and prognosis. All patients were boys with 3-8 loose or watery stools each day and routine fecal tests were normal. Abdominal tumors were identified by B-ultrasound. Drugs were ineffective. Three patients underwent surgery, and the remaining three patients received surgery and chemotherapy. Diarrhea stopped after treatment in five patients. Two patients died due to intractable hypokalemia. The tumor was located in the adrenal gland in four patients, in the upper retroperitoneum in one patient, and in the presacral area in one patient. Pathologic findings were NB and ganglioneuroblastoma. Five patients were at clinical stage I-II, and one was at stage III. Four patients survived (followed-up for 6 mo to 4 years). Immunohistochemical staining for VIP was positive. Refractory diarrhea is a paraneoplastic syndrome of NB and is rare. Patients aged 1-3 years who present with chronic intractable diarrhea should be followed closely. Intractable diarrhea, hypokalemia, and dysplasia are the initial clinical manifestations. Increased VIP is characteristic of this disease. Potassium supplementation plays a vital role in the treatment procedure, especially preoperatively. The prognosis of diarrheal NB is good following appropriate treatment.

Zinc status of human IMR-32 neuroblastoma cells influences their susceptibility to iron-induced oxidative stress.

The current work tested the hypothesis that the zinc status of a cell influences its sensitivity to iron-induced oxidative stress. Human IMR-32 neuroblastoma cells were cultured for 24 h in nonchelated control media (5 microM zinc; 4.5 microM iron), or in media that was treated with DTPA to reduce its zinc content (chelated media). Chelated media was supplemented with zinc to achieve concentrations of 1.5-50 microM Zn. The media was then replaced with serum-free complex media (0.9 microM Zn) with either no added iron (0.6 microM Fe), or iron (FeCl(3)) added at concentrations ranging from 15 to 100 microM. Cells were cultured for an additional 3- to 24-hour period. Over the 24-hour period, cells cultured in the control iron media had good viability, and they displayed the gross morphology typical of these cells in culture. With 100 microM iron, cell viability was low in all groups. After 24 h and at iron concentrations between 15-50 microM, cells that had been cultured in the low zinc-chelated media (1.5 microM Zn) showed a concentration-dependent increase in 5 (or 6)-carboxy-2'7'-dichlorodihydrofluorescein diacetate (DCDCDHF) fluorescence (oxidative stress) and decrease in cell viability. A positive correlation between both parameters was observed (r = 0.92). These cells had altered morphology and high level of nucleosomes suggestive of cell death by apoptosis. These results support the concept that the zinc status of IMR-32 neuroblastoma cells modulates their sensitivity to iron overload.

VEGF upregulates Bcl-2 expression and is associated with decreased apoptosis in neuroblastoma cells.

BACKGROUND/PURPOSE: Both the expression of Bcl-2 and the amount of vascular endothelial growth factor (VEGF) are increased in neuroblastoma cells cocultured with hepatocytes. The authors hypothesize that VEGF upregulates Bcl-2 expression by the neuroblastoma cells and protects them from apoptotic stimuli. METHODS: To determine whether VEGF will induce Bcl-2 expression in neuroblastoma cells, the cells are plated with standard media (control) or media supplemented with VEGF. After 24 hours, Bcl-2 expression is measured. To determine whether VEGF protects neuroblastoma cells from apoptosis, the cells are subjected to tumor necrosis factor alpha (TNF-alpha) or serum starvation to induce apoptosis either with or without VEGF added to the culture media. The cells are collected and apoptosis measured using the deoxynucleotidyltransferase-mediated dUTP neck end labeling (TUNEL) method. RESULTS: VEGF increases Bcl-2 expression by 33% over cells cultured in standard media. Serum starving the tumor cells or adding TNF-alpha significantly increases the percentage of apoptotic cells. The addition of VEGF significantly protects the neuroblastoma cells from the apoptotic effects of both serum starvation and TNF-alpha. CONCLUSIONS: VEGF increases the expression of Bcl-2 and also abrogates TNF-alpha and serum starvation-induced apoptosis in neuroblastoma cells in vitro. VEGF may promote neuroblastoma survival not only through angiogenesis, but also by altering apoptosis and its regulating proteins.

Detection of microscopic disease: comparing histology, immunocytology, and RT-PCR of tyrosine hydroxylase, GAGE, and MAGE.

BACKGROUND: We first explored the use of multiple molecular markers to overcome tumor heterogeneity. Sixty-seven neuroblastoma (NB) tumors were tested for the expression of GAGE, MAGE-2, MAGE-2, MAGE-3, and MAGE-4 by RT-PCR and then chemiluminescence; 82% of tumors had detectable GAGE, and 88% expressed at least one of the four MAGE genes. PROCEDURE AND RESULTS: By combining GAGE and MAGE, 64 of 67 (95%) of tumors became detectable; 17 of 67 coexpressed all five molecular markers. Neither GAGE nor MAGE expression correlated with stage. GAGE was found to have the broadest (18 of 18) expression among stage 4 tumors. Two hundred fifty-nine bone marrows from 99 patients were then studied for NB positivity by four detection methods: histology, immunocytology, and molecular detection by GAGE and tyrosine hydroxylase (TH) mRNA. Two hundred seven samples were NB-positive by one detection method. All four techniques were comparable in detecting tumor cells at diagnosis and at relapse. GAGE and immunocytology were far more sensitive than histology and TH mRNA when marrows were sampled during chemotherapy and at the time of clinical remission. CONCLUSIONS: By combining multiple molecular markers and independent screening techniques, we may be able to overcome tumor heterogeneity and expedite the detection of microscopic disease in the clinical management of neuroblastoma.

[Eight year history of neuroblastoma in an adult patient. Value of 123I-MIBG and 111In-DTPA-D-Phe-octreotide scintigraphy]. / Neuroblastoma de 8 años de evolución en paciente adulto: valor de la gammagrafía con 123I-MIBG y con 111In-DTPA-D-Phe-octreótido.

A case of a 30 year old male with an eight year history of neuroblastoma and whose general health was good is presented. After his last check-up, which included a CT scan and 99mTc-MDP bone scintigraphy, a 123I-MIBG and 111In-DTPA-D-Pheoctreotide scintigraphy was performed and provided us with complementary data that contributed to a more precise diagnosis of the location and extension of the neuroblastoma and to the biological features of the tumor. Thus, this report deals with an adult neuroblastoma patient whose general health is good in whom the exact extension of the lesion was determined by a combination of diagnostic imaging techniques.

gamma-Linolenic acid supplementation can affect cancer cell proliferation via modification of fatty acid composition.

We examined the effect of gamma-linolenic acid (GLA) supplementation on the growth and fatty acid composition of three human tumor cell lines (the neuroblastoma CHP-212, the tubal carcinoma TG, and the colon carcinoma SW-620), in order to evaluate the relationship between GLA-induced tumor cell death and the distribution of fatty acids in tumor cells. At the highest GLA concentrations (10 and 20 micrograms/ml), the DNA synthesis was completely abolished; at 5 micrograms/ml GLA only SW-620 cells did not proliferate, while CHP-212 and TG cells showed a residual [3H]-thymidine incorporation. GLA levels were very low in cells grown in control medium; GLA supplementation caused a significant incorporation of GLA itself in all the cell lines at each concentration. In TG and CHP-212 cells, GLA was metabolized, although to a different extent, to dihomo-gamma linolenic acid and arachidonic acid. SW-620 cells neither elongated nor desaturated the incorporated GLA. The highest cytostatic effect was reached when GLA was not transformed into its metabolites, suggesting that the GLA toxicity to tumor cells is not dependent on metabolites but is due to GLA itself.

Complementary chromatographic analysis of free diacylglycerols and potential glycerophospholipid precursors in human SH-SY5Y neuroblastoma cells following incubation with lithium chloride.

We performed detailed chromatographic analyses on the molecular species of the major glycerophospholipids (GPLs) and free sn-1,2-diacylglycerols (DAGs) from SH-SY5Y human neuroblastoma cells following incubation with or without LiCl. For this comparison the inositol, choline, ethanolamine and serine GPLs were dephosphorylated with phospholipase C and the released sn-1,2-diacylglycerols along with the DAGs were subjected to high-temperature GLC on polar and non-polar capillary columns as their trimethylsilyl and tert.-butyl-dimethylsilyl ethers. A 30-min incubation with 10 mM LiCl increased the total amount of human neuroblastoma DAGs by 32-58% (P < 0.05) to 2.6 pmol/micrograms cell protein. This was accompanied by a limited qualitative shift in the molecular species pattern, the most obvious of which was the increase (13%) in the major saturated-polyunsaturated molecular species and the ca. 46% increase in the minor 18:1-18:1 species over control levels. The DAGs originated mainly from the inositol GPLs (IGPLs), as indicated by the high levels of the characteristic 18:0-20:4n6 (18:0-20:3n9) species in both IGPLs and DAGs, and to a lesser extent from the choline GPLs (CGPLs), as indicated by the high proportion in CGPLs of the oligoenoic species, which were largely absent from IGPLs. Alkenylacylglycerols were not detected in DAGs, although they made up some 60% of the total ethanolamine GPLs (EGPLs). No significant changes in the molecular species composition of the cellular GPLs, including IGPLs, were detected after exposure to LiCl.

Binding of heparan sulfate glycosaminoglycan to beta-amyloid peptide: inhibition by potentially therapeutic polysulfated compounds.

Heparin sulfate proteoglycans are believed to play an important role in amyloidosis as pathologic chaperones. They bind to amyloidogenic proteins and may mediate the deposition and fibrillogenesis of amyloid at specific tissue sites. In the present study, we demonstrate that heparin sulfate glycosaminoglycan and proteoglycan both bind to the beta-amyloid peptide involved in Alzheimer's disease. The interaction of heparan sulfate proteoglycan and glycosaminoglycan can be inhibited by other sulfated compounds such as heparin, dextran sulfate and pentosan polysulfate. These polysaccharides which are currently used clinically, their derivatives or analogs may be effective as therapeutic agents to prevent or slow the progression of amyloidogenesis in Alzheimer's disease or other amyloidogenic disorders.

Production of immunoreactive corticotropin-releasing hormone in various neuroendocrine tumors.

The concentrations of immunoreactive (IR) corticotropin-releasing hormone (CRH) in 218 neuroendocrine tumors were determined by CRH radioimmunoassay. The tumors examined were 86 pancreatic endocrine tumors (PET), 22 neuroblastic tumors (NBT), 26 carcinoid tumors (CA), 24 pheochromocytomas (PHEO), 40 small cell lung carcinomas (SCLC) and 20 medullary thyroid carcinomas (MTC). IR-CRH was detectable in 21 neuroendocrine tumors (10 PET, four NBT, three CA, two PHEO and two SCLC) at levels of 10-2,700 ng/g wet weight (9.6%). The 21 patients with these CRH-producing tumors showed no clinical symptoms suggestive of Cushing's syndrome. The levels of plasma IR-CRH extracted by immunoaffinity chromatography were < 7.5 pg/ml in five normal subjects and a patient with a neuroblastic tumor containing 55 ng/g wet weight IR-CRH, but in a patient with a thymic carcinoid tumor containing 1,000 ng/g wet weight IR-CRH, the plasma level was elevated to 180 pg/ml. This patient did not have Cushing's syndrome nor an elevated plasma adrenocorticotropic hormone (ACTH) level. The concentrations of nine peptides (growth hormone-releasing hormone, somatostatin, ACTH, calcitonin, gastrin-releasing peptide, glucagon, vasoactive intestinal peptide, neuropeptide tyrosine and pancreatic polypeptide) were determined in extracts of the 21 IR-CRH-producing tumors. Some of these peptides were frequently found to be produced concomitantly with CRH. The results indicate IR-CRH to be produced by various neuroendocrine tumors, but Cushing's syndrome, due to the CRH, to be very rare. The results also show that CRH-producing tumors produce multiple hormones.