title: Atypical heat shock response and acquisition of thermotolerance in P388D1 cells.
abstract: Reports of atypical heat shock response in some tumour cell lines emphasize the possibilities of alternate stress response mechanisms. We demonstrate here that P388D1, a mouse macrophage tumour cell line, failed to induce heat shock proteins (HSPs) in response to either heat stress (42 °C, 1h) or to heavy metal stress induced by arsenic trioxide (5-20 μM). Heat shock transcriptional factor 1 (HSF1) that mediates transcriptional up regulation of HSPs during stress was found to be deficient in transactivation despite its binding to the promoter region of HSP genes. Interestingly, cells exhibited thermotolerance in the absence of induced HSPs. However, the tolerance was abrogated in cells treated with cycloheximide (250 ng/ml) suggested that thermotolerance was dependent on de novo protein synthesis.
authors.affiliation: Apoptosis Research Centre, School of Natural Sciences, National University of Ireland, Galway, Ireland. oommen1978@gmail.com
authors.forename: Deepu
authors.initials: D
authors.lastname: Oommen
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Giricz
authors.forename: Usha K
authors.initials: UK
authors.lastname: Srinivas
authors.forename: Afshin
authors.initials: A
authors.lastname: Samali
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003513:Cycloheximide / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics / Q000502:physiology*; D006358:Hot Temperature; D051379:Mice; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C490017:Hsf1 protein, mouse; D014157:Transcription Factors; D003513:Cycloheximide