vitamin-b-12 and Melanoma

Vitamin B12 and folate are the major micronutrients that play significant roles in DNA synthesis. Epidemiological studies and clinical evidences displayed alterations in serum concentrations folate and of vitamin B12 in various human malignancies, yet their roles in patients with melanoma have yet to be understood.. To assess circulating vitamin B12 and folate concentrations of patients with melanoma and compare them with other malignant tumors and healthy subjects.. A total of 98 skin melanoma cases from university clinic were enrolled into the study. Serum vitamin B12 and folate concentrations were analyzed by electrochemiluminescence binding assay.. Circulating levels of vitamin B12 in patients with melanoma were similar compared with other malignancies and healthy controls (P > .05). However, melanoma cases had significantly lower serum folate concentrations than healthy control group (P = .04). Melanoma patients with metastatic disease (P = .001) and with short history of disease (P = .05), and those who had active diseases in course of the study (P = .04) had low serum folate concentrations.. Serum levels of folate were found significantly lower in melanoma cases, and this association was stronger for patients with metastatic melanoma; however, no such association was found between melanoma and serum vitamin B12 levels.

Topics: Folic Acid; Humans; Melanoma; Skin Neoplasms; Vitamin B 12

Whereas the prevalence of several cancer types is decreasing, skin malignancies are growing more common every year. Malignant melanoma is the most aggressive form of skin cancer with high metastatic capacity. In most cases, malignant melanoma shows acquired therapy resistance. We evaluated the ability of Ocoxin, a natural compound-based antioxidant and anti-inflammatory nutritional complement, to exert an antitumor effect in melanoma. To do so, the cytotoxicity of Ocoxin in a panel of BRAF-mutated murine and human melanoma cell lines was tested alone and in combination with BRAF inhibitor Vemurafenib. Our results revealed a potent cytotoxic effect of Ocoxin against melanoma cells and a synergic effect when combined with Vemurafenib, reducing viability and increasing apoptosis. Besides, Ocoxin interferes with the cell cycle, impairs the inherent and fibroblast-mediated melanoma cell migration, and reduces resistance to BRAF inhibition. Proteomic analysis revealed reduced tumor secretion of inflammatory factors Galectin-1, Osteopontin, CCL5, and CCL9 upon treatment with Ocoxin. Moreover, RNASeq showed that Ocoxin downregulated the cell cycle and proliferation-related genes. In vivo, Ocoxin reduced the number of lung metastasis of YUMM-1.7 melanoma cells. Therefore, Ocoxin arises as a good candidate for clinical trials analyzing the beneficial effects in patients suffering from this cutaneous malignancy.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Cancer-Associated Fibroblasts; Cell Line, Tumor; Drug Resistance, Neoplasm; Folic Acid; Humans; Melanoma; Melanoma, Cutaneous Malignant; Mice; Pantothenic Acid; Plant Extracts; Protein Kinase Inhibitors; Proteomics; Proto-Oncogene Proteins B-raf; Skin Neoplasms; Vemurafenib; Vitamin B 12; Vitamin B 6; Zinc Sulfate

Rapidly growing cells show an increased demand for nutrients and vitamins. The objective of our work is to exploit the supply route of vitamin B12 to deliver new derivatives of this vital vitamin to hyperproliferative cells. To date, radiolabeled ((57)Co and (111)In) vitamin B12 derivatives showed labeling of tumor tissue but also undesired high accumulation of radioactivity in normal tissue. By abolishing the interaction of a tailored vitamin B12 derivative to its transport protein transcobalamin II and therefore interrupting transcobalamin II receptor and megalin mediated uptake in normal tissue, preferential accumulation of a radiolabeled vitamin in cancer tissue could be accomplished. We identified transcobalamin I on tumors as a possible new receptor for this preferential accumulation of vitamin-mediated targeting. The low systemic distribution of radioactivity and the high tumor to blood ratio opens the possibility of a more successful clinical application of vitamin B12 for imaging or therapy.

Topics: Antineoplastic Agents; Biological Transport; Carcinoma; Cell Line, Tumor; Humans; Kidney Neoplasms; Melanoma; Transcobalamins; Urinary Bladder Neoplasms; Vitamin B 12

Immune activation and cell proliferation may contribute to the development of increased homocysteine concentrations in patients with malignant diseases. In this study, we investigated the effect of interferon-alpha (IFN-alpha) on plasma homocysteine concentrations in patients being treated for malignant melanoma. In parallel, neopterin formation and tryptophan degradation were monitored to assess the capacity of IFN-alpha to activate macrophages. Plasma concentrations of homocysteine, folate, and vitamin B(12) were determined in 15 patients with malignant melanoma during 12 weeks of high-dose IFN-alpha therapy. Concurrently, concentrations of neopterin, tryptophan, and kynurenine were measured, and the kynurenine/tryptophan ratio (kyn/trp) was calculated. Homocysteine and folate concentrations during treatment with IFN-alpha did not differ from baseline. In contrast, significant increases in neopterin formation and tryptophan degradation were apparent during IFN-alpha therapy. Plasma concentrations of vitamin B(12) and cysteine also increased. These results indicate that IFN-alpha directly activates macrophages to release neopterin and to degrade tryptophan, but obviously treatment with INF-alpha did not affect homocysteine metabolism.

Topics: Adult; Aged; Antineoplastic Agents; Female; Folic Acid; Homocysteine; Humans; Interferon alpha-2; Interferon-alpha; Kynurenine; Macrophage Activation; Male; Melanoma; Middle Aged; Neopterin; Predictive Value of Tests; Recombinant Proteins; Tryptophan; Vitamin B 12

The ubiquitous plasma membrane transcobalamin II receptor (TC II-R) mediates uptake of cobalamin (Cbl; vitamin B12), an essential micronutrient. Tumors often require more Cbl than normal tissue, and increased Cbl uptake may result from increased TC II-R expression. To examine whether Cbl could therefore be used as a carrier molecule to target a chemotherapy drug, we tested an analogue of Cbl with nitric oxide as a ligand, nitrosylcobalamin (NO-Cbl). Because interferon beta (IFN-beta) has antitumor effects and increases expression of some membrane receptors, we examined whether it may enhance the effects of NO-Cbl.. Antiproliferative effects of NO-Cbl were assessed in 24 normal and cancer cell lines. Xenograft tumors of human ovarian cancer NIH-OVCAR-3 cells were established in athymic nude mice, and tumor growth was monitored after treatment with NO-Cbl and IFN-beta, both individually and concomitantly. TC II-R expression and apoptosis was monitored in vitro and in vivo. RNA protection assays and mitochondrial membrane potential assays were used to distinguish the extrinsic and intrinsic apoptotic pathways, respectively.. Cancer cell lines were more sensitive to NO-Cbl (with ID(50)s [the dose that inhibits growth by 50%] as low as 2 microM) than normal cell lines (with ID(50)s of 85-135 microM). Single-agent NO-Cbl and IFN-beta treatment of NIH-OVCAR-3 xenografts induced tumor regression, whereas combination treatment induced tumor eradication. IFN-beta treatment increased TC II-R expression in vitro and uptake of [(57)Co]cobalamin in vivo. Compared with NIH-OVCAR-3 cells treated with NO-Cbl, cells treated with NO-Cbl and IFN-beta were more apoptotic and expressed higher mRNA levels of various apoptosis-associated genes. No changes in mitochondrial membrane potential were observed in cells treated with NO-Cbl.. NO-Cbl inhibited tumor growth in vivo by activating the extrinsic apoptotic pathway. The increased expression of TC II-R induced by IFN-beta resulted in enhanced antitumor effects with NO-Cbl both in vitro and in vivo.

Topics: Animals; Annexin A5; Antineoplastic Agents; Apoptosis; Blotting, Western; Breast Neoplasms; Caspase 8; Caspase 9; Caspases; Cell Division; Combined Modality Therapy; Drug Synergism; Female; Humans; Immunoenzyme Techniques; Interferon-beta; Male; Melanoma; Membrane Potentials; Mice; Mice, Nude; Mitochondria; Nitric Oxide; Nitroso Compounds; Ovarian Neoplasms; Receptors, Cell Surface; Rhodamines; Ribonuclease, Pancreatic; Tumor Cells, Cultured; Vitamin B 12

To identify the defect in cobalamin metabolism in the human melanoma cell line MeWoLC1, and to determine how frequent this defect is in other methionine-dependent tumour cell lines.. Biochemical and somatic cell genetics study.. Aspects of cobalamin metabolism were measured in a panel of 14 human tumour cell lines that were unable to proliferate normally in medium in which methionine had been replaced by its metabolic precursor homocysteine (methionine-dependent cell lines).. The human melanoma cell line MeWoLC1 was unique among these cell lines, in that it was characterized by decreased uptake of cobalamin, decreased synthesis of coenzyme derivatives, and decreased functional activity of the cobalamin-dependent enzymes methionine synthase and methylmalonylCoA mutase. This phenotype was identical to that observed in fibroblasts from patients with the cblC and cblD inborn errors of cobalamin metabolism. The defect in cobalamin metabolism in MeWoLC1 was complemented in somatic cell complementation analysis by cblA, cblB, cblD, cblE and cblG fibroblasts, but not by cblC fibroblasts, strongly suggesting that the defect in this cell line affects the cblC locus. Similar changes in cellular cobalamin metabolism were not seen in any other methionine-dependent cell line in the panel, suggesting that there may be multiple causes of methionine dependence, and that inactivation of the cblC locus may not be a common cause of this phenotype in transformed cells.. The defect underlying methionine dependence in MeWoLC1 appears to involve the locus that is affected in patients with the cblC inborn error of metabolism. This defect does not seem to be common among other methionine-dependent cell lines.

Topics: Carbon Radioisotopes; Culture Media; Humans; Leukemia; Melanoma; Methionine; Neoplasms; Propionates; Tetrahydrofolates; Tumor Cells, Cultured; Vitamin B 12

Our aim was to identify the biochemical defect responsible for the inability of highly growth autonomous human tumor cells to proliferate in culture medium devoid of methionine, but containing homocysteine and 5-methyletrahydrofolic acid. We have adopted the terms "homocysteine-responsive" and "homocysteine-nonresponsive" to describe cells which can or cannot proliferate in methionine-free homocysteine-supplemented medium. Using a panel of genetically related homocysteine-responsive and -nonresponsive human melanoma cell lines, the results from a number of experiments indicate that acquisition of the "homocysteine-nonresponsive phenotype" is associated with the reduced intracellular accumulation of methyl-cobalamin, a critical cofactor of the methionine synthase enzyme. When in vitro methionine synthase assays were performed in the presence of exogenously added methyl-cobalamin, specific methionine synthase activity in extracts obtained from homocysteine-responsive cells was only twofold greater than that observed with extracts prepared from homocysteine-nonresponsive cells. However, when exogenous methyl-cobalamin was omitted from the enzyme assays, methionine synthase activity in extracts derived from homocysteine-nonresponsive cells was dramatically reduced, compared with the small decrease observed with homocysteine-responsive cell extracts. Compared with their homocysteine-responsive counterparts, homocysteine-nonresponsive cells exhibited increased levels of cobalamin efflux and decreased intracellular accumulation of methyl-cobalamin. There was a clear relationship between the abilities of these related melanoma cell lines to proliferate in methionine-free homocysteine-supplemented medium, and the extent of cobalamin loss and capacity of exogenously added methyl-cobalamin to stimulate in vitro methionine synthase activity. These results indicate a link between alterations in the intracellular trafficking and/or metabolism of cobalamin and the increased growth autonomy of human melanoma cells.

Topics: 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; Cell Division; Homocysteine; Humans; Melanoma; Methionine; Phenotype; Tetrahydrofolates; Tumor Cells, Cultured; Vitamin B 12

In order to identify the biochemical defect(s) responsible for the reduced levels of DNA 5-methylcytosine (5-mCyt) found within highly metastatic (in athymic "nude" mice) variants of the poorly metastatic human melanoma cell line MeWo, the ability of these cells to grow in culture medium devoid of exogenous methionine but containing either homocysteine (Hcy) or 5'-deoxy-5'-methylthioadenosine (MeSAdo) was determined. In contrast to the parental MeWo tumor line, many (but not all) of these malignant variants were completely unable to proliferate in methionine-free homocysteine-containing medium. Many of these malignant variants also exhibited a reduced ability to proliferate in methionine-free MeSAdo-containing medium. Cell lines established from "artificial" metastases of MeWo or its cloned sublines, exhibited no consistent reduction in their ability to grow in methionine-free medium containing either Hcy or MeSAdo. These observations suggest that alterations in S-adenosylmethionine(AdoMet)-dependent transmethylation reactions may contribute to "progression" of the MeWo tumor from a relatively benign to a highly autonomous and malignant state.

Topics: Cell Division; Culture Media; Homocysteine; Humans; Melanoma; Methionine; Neoplasm Metastasis; S-Adenosylmethionine; Tumor Cells, Cultured; Vitamin B 12

Topics: Adrenal Gland Neoplasms; Adult; Binding Sites; Cells, Cultured; Centrifugation; Cobalt Radioisotopes; Dialysis; Female; Granulocytes; Hodgkin Disease; Humans; Leukemia, Lymphoid; Leukemia, Myeloid; Leukocytes; Lung Neoplasms; Male; Melanoma; Multiple Myeloma; Protein Binding; Proteinuria; Pyelonephritis; Time Factors; Vitamin B 12