ascorbic-acid and Retinoblastoma

We obtained primary culture of retinoblastoma cells and evaluated the resistance of cultured ells to chemotherapy. The study included 19 patients aged 6-64 months (mean 27.9±17.4 months); of these, 6 (31.6%) patients with bilateral retinoblastoma and 13 (68.4%) patients with unilateral form. In 18 (94.7%) patients, group E retinoblastoma was diagnosed. Enucleation was performed in all patients; in 94.7% cases, low-differentiated retinoblastoma was identified. Samples of the tumor tissue were taken to derive a cell culture and to study drug resistance and metabolic activity of cells (MTT test). In 4 cases, adhesion primary cultures of retinoblastoma were derived. Cytological verification of the obtained cultures was performed. The primary cultures were derived from 4 of 6 bilateral tumors and from none of 13 unilateral tumors (p=0.003). There were no statistically significant correlations with patient age (p=0.33) and the presence of calcifications in the tumor (p=0.26). MTT test revealed no differences in the sensitivity of cell cultures to irinotecan and ifosfamide. Pronounced differences in the resistance of cell cultures were observed for oxaliplatin and ascorbic acid. MTT test with evaluation of drug resistance can be used both in clinical practice for adjusting chemotherapy regimen and in development of new approaches to the treatment of retinoblastoma with assessment of in vivo tumor cell resistance in animal models.

Topics: Antineoplastic Agents; Ascorbic Acid; Camptothecin; Cell Survival; Child; Child, Preschool; Drug Resistance, Neoplasm; Female; Humans; Ifosfamide; Infant; Irinotecan; Male; Organoplatinum Compounds; Oxaliplatin; Retinoblastoma; Tumor Cells, Cultured

Retinoblastoma is one of the most common ocular malignancies in children under the age of six. Occasionally, retinoblastoma metastasizes to extraocular organs including the bone, lung and brain. Left untreated, retinoblastoma is fatal. At present, there is no effective treatment for metastatic retinoblastoma. We investigated the antineoplastic activity of a nutrient mixture (NM) (lysine, proline, ascorbic acid and green tea extract) at concentrations of 10, 50, 100, 500 and 1,000 µg/ml in triplicate at each dose in the human malignant retinoblastoma Y-79 cell line. The parameters used were cell proliferation, expression of matrix metalloproteinases (MMPs), invasion through Matrigel, morphology and apoptosis. Cell viability was assessed by trypan blue dye exclusion test. Invasion was evaluated through Matrigel and MMP activity by gelatinase zymography. H&E staining for morphological cell alterations and apoptotic studies using the Live Green Poly Caspase Detection kit were also conducted. The nutrient mixture at 10-100 µg/ml demonstrated approximately 25% toxicity towards Y-79 retinoblastoma cells and significant toxicity at 500 and 1,000 µg/ml. The Y-79 cells secreted only MMP-2 as demonstrated by zymography; the nutrient mixture had no effect on MMP-2 expression up to 100 µg/ml, but completely blocked it at 500 µg/ml. Importantly, Y-79 retinoblastoma cells were not invasive through Matrigel. H&E staining showed cell morphological changes related to apoptosis, which was confirmed using the Live Green Poly Caspase Detection kit. Our results suggest that this nutrient mixture, which inhibited cell proliferation, expression of MMP-2 and induced apoptosis, may be a candidate for further exploration for its therapeutic potential in metastatic retinoblastoma.

Topics: Antineoplastic Agents; Antioxidants; Apoptosis; Ascorbic Acid; Cell Adhesion; Cell Movement; Cell Proliferation; Flow Cytometry; Humans; Lysine; Plant Extracts; Proline; Retinoblastoma; Tea; Tumor Cells, Cultured

Aqueous humor from children with retinoblastoma obtained at enucleation and from eyes with adult cataracts were assayed with electrochemical liquid chromatography (Model 5500 Coulochem electrode array system) for metabolites of tyrosine, tryptophan metabolic pathways, catecholamine degradation pathways and ascorbate. More than 20 metabolites were identified in human aqueous for the first time. High levels of ascorbate were found in aqueous of eyes with adult cataracts (254, 336 ng/ml). Tyrosine metabolism in both sets of eyes was through dopamine. Vandylmandelic acid (VMA), homovanillic acid (HVA), and 3-methoxy, 4-hydroxyphenylglycol (MHPG) were all detected in retinoblastoma eyes. Although eyes with either adult cataracts or childhood retinoblastoma convert tryptophan through the serotonin pathway, retinoblastoma eyes metabolize tryptophan through the kynurenine pathway to a greater degree than adult cataract eyes.

Topics: Adult; Amino Acids; Aqueous Humor; Ascorbic Acid; Cataract; Catecholamines; Child, Preschool; Chromatography, High Pressure Liquid; Eye Neoplasms; Humans; Retinoblastoma

Y79 human retinoblastoma cells have a high capacity to reduce ascorbate autooxidation rates through the reduction of the ascorbate free radicals generated in the oxidation process. Responsible of this capacity is a plasma membrane redox system, which might be functionally related to the Na+/H+ antiporter. Ascorbate has cytotoxic effect on Y79 cells in long-term incubations in the presence of limited amounts of serum in the medium.

Topics: Ascorbic Acid; Carrier Proteins; Cell Division; Cell Membrane; Free Radicals; Humans; NADH, NADPH Oxidoreductases; Oxidation-Reduction; Retinoblastoma; Sodium-Hydrogen Exchangers; Tumor Cells, Cultured