title: Retinoic acid inhibits the cytoproliferative response to weak 50‑Hz             magnetic fields in neuroblastoma cells.
abstract: We previously reported that intermittent exposure to a 50‑Hz magnetic field (MF)             at 100 µT stimulates cell proliferation in the human neuroblastoma cell line NB69.             The present study aimed to investigate whether the magnetic field-induced growth             promotion also occurs at a lower magnetic flux density of 10 µT. To this purpose,             NB69 cells were subjected for 42 h to intermittent exposure, 3 h on/3 h off, to             a 50‑Hz MF at a 10 or 100 µT magnetic flux density. The field exposure took place             either in the presence or in the absence of the antiproliferative agent retinoic             acid. At the end of the treatment and/or incubation period, the cell growth was             estimated by hemocytometric counting and spectrophotometric analysis of total             protein and DNA contents. Potential changes in DNA synthesis were also assessed             through proliferating cell nuclear antigen (PCNA) immunolabeling. The results             confirmed previously reported data that a 42-h exposure to a 50‑Hz sine wave MF             at 100 µT promotes cell growth in the NB69 cell line, and showed that 10 µT induces             a similar proliferative response. This effect, which was significantly associated             and linearly correlated with PCNA expression, was abolished by the presence of             retinoic acid in the culture medium.
authors.affiliation: Department of Research-BEM, IRYCIS, Hospital Ramon y Cajal, 28034 Madrid, Spain. angeles.trillo@hrc.es
authors.forename: María Ángeles
authors.initials: MÁ
authors.lastname: Trillo
authors.forename: María Antonia
authors.initials: MA
authors.lastname: Martínez
authors.forename: María Antonia
authors.initials: MA
authors.lastname: Cid
authors.forename: Alejandro
authors.initials: A
authors.lastname: Úbeda
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D060526:Magnetic Fields; D009447:Neuroblastoma; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D018809:Proliferating Cell Nuclear Antigen; D014212:Tretinoin