title: Acute and long-term effects of hyperthermia in B16-F10 melanoma cells.
abstract: OBJECTIVE
  Hyperthermia uses exogenous heat induction as a cancer therapy. This work addresses the acute and long-term effects of hyperthermia in the highly metastatic melanoma cell line B16-F10.
  
  
  METHODS
  Melanoma cells were submitted to one heat treatment, 45°C for 30 min, and thereafter were kept at 37°C for an additional period of 14 days. Cultures maintained at 37°C were used as control. Cultures were assessed for the heat shock reaction.
  
  
  RESULTS
  Immediately after the heat shock, cells began a process of fast degradation, and, in the first 24 h, cultures showed decreased viability, alterations in cell morphology and F-actin cytoskeleton organization, significant reduction in the number of adherent cells, most of them in a process of late apoptosis, and an altered gene expression profile. A follow-up of two weeks after heat exposure showed that viability and number of adherent cells remained very low, with a high percentage of early apoptotic cells. Still, heat-treated cultures maintained a low but relatively constant population of cells in S and G(2)/M phases for a long period after heat exposure, evidencing the presence of metabolically active cells.
  
  
  CONCLUSIONS
  The melanoma cell line B16-F10 is susceptible to one hyperthermia treatment at 45°C, with significant induced acute and long-term effects. However, a low but apparently stable percentage of metabolically active cells survived long after heat exposure.
authors.affiliation: Laboratório de Farmacologia e Biocompatibilidade Celular, Faculdade de Medicina Dentária, Universidade do Porto, Porto, Portugal.
authors.forename: Mónica Pereira
authors.initials: MP
authors.lastname: Garcia
authors.forename: José Roberto Tinoco
authors.initials: JR
authors.lastname: Cavalheiro
authors.forename: Maria Helena
authors.initials: MH
authors.lastname: Fernandes
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002453:Cell Cycle / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D048430:Cell Shape / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D015870:Gene Expression; D006358:Hot Temperature; D006979:Hyperthermia, Induced; D008546:Melanoma, Experimental / Q000628:therapy*; D051379:Mice; D013995:Time; D014407:Tumor Cells, Cultured