hydroxocobalamin and Laryngeal-Neoplasms

We have shown that hydroxycobalamin (vitamin В

Topics: Apoptosis; Autophagy; Carcinoma; Cell Death; Cell Line, Tumor; Cell Survival; Ditiocarb; Drug Synergism; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Humans; Hydroxocobalamin; Laryngeal Neoplasms; Larynx; Mitochondria; Oxidative Stress; Vacuoles; Vitamin B 12; Vitamins

Incubation of human laryngeal epidermoid carcinoma HEp-2 cells with hydroxocobalamin (vitamin B12b) and ascorbic acid (vitamin C) for 1 h initiated oxidative stress accompanied by damage to mitochondria and increase in intracellular oxidative activity. Studies of the kinetics of these processes showed that the increase in intracellular H2O2 activity and mitochondrial damage are more likely a result, but not the cause of cell apoptosis during the first hour of their incubation with vitamins B12b and C.

Topics: Ascorbic Acid; Calcium; Cell Death; Cell Line, Tumor; Fluoresceins; Fluorescent Dyes; Humans; Hydrogen Peroxide; Hydroxocobalamin; Kinetics; Laryngeal Neoplasms; Membrane Potentials; Mitochondria; Oxidative Stress; Spectrometry, Fluorescence; Time Factors; Vitamin B 12

The confluence-dependent resistance of human larynx carcinoma HEp-2 cells to hydrogen peroxide and a new antitumor drug based on the combination of vitamins C and B12b was studied. It was found that this resistance in growing cells is suppressed by the disruption of intercellular contacts by EGTA and is related neither to the activity of P-glycoprotein nor to the content of intracellular glutathione and the activities of glutathione S-transferases, glutathione peroxidase and glutathionine reductase. Here we showed that the level of expression of the small heat shock protein hsp27, which is known to protect cells from a variety of stresses associated with apoptosis, in growing confluent cells both in the presence and absence of the vitamins B12b and C is much higher (about 20-25 times) than in non-confluent cells. Taken together, the results suggest that the confluence-dependent resistance of cells to the combination of vitamins C and B12b and to hydrogen peroxide is mediated by hsp27 overexpression, which is activated via cell-cell adhesion.

Topics: Antineoplastic Combined Chemotherapy Protocols; Ascorbic Acid; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carcinoma; Cell Adhesion; Cell Communication; Cell Culture Techniques; Cell Division; Drug Resistance, Neoplasm; Egtazic Acid; Glutathione; Heat-Shock Proteins; HSP27 Heat-Shock Proteins; Humans; Hydrogen Peroxide; Hydroxocobalamin; Laryngeal Neoplasms; Molecular Chaperones; Neoplasm Proteins; Tumor Cells, Cultured