title: Expression of antisense hsp70 is a major determining factor in heat-induced cell death of P-19 carcinoma cells.
abstract: Overexpressed heat shock protein 70 (Hsp70) is known to be associated with thermoprotection in a number of cell lines and transgenic animals. We hypothesized that because overexpression of Hsp70 protects cells from lethal heat stress, inhibition of expression should make cells susceptible to heat stress. The model used for this study was a stably transfected P-19 carcinoma cell line expressing antisense hsp70 under the control of the hsp70b promoter. The results showed marked inhibition of Hsp70 expression after heat shock correlated with heat-induced cell death. Hsp90 and Hsc70 protein expression were not affected by the antisense construct. Unexpectedly, heme oxygenase (HO-1), another highly inducible heat shock protein, was not induced after heat shock in the antisense hsp70 cell line. Heat shock transcription factor-1 (HSF-1) was in a highly phosphorylated state in the antisense cell line before and after heat shock. This was in contrast to the untransfected control P-19 cells where HSF-1 was primarily highly phosphorylated after heat shock. A control cell line expressing only the vector, pMAMneo, without the antisense construct also showed partial loss of Hsp70 induction but not increased cell death after heat shock. The findings support the role of Hsp70 in thermoresistance.
authors.affiliation: VA Greater Los Angeles Healthcare System, Department of Neurology, Regeneration of the CNS Laboratory, Sepulveda, CA 91343, USA. rnishimu@ucla.edu
authors.forename: R N
authors.initials: RN
authors.lastname: Nishimura
authors.forename: D
authors.initials: D
authors.lastname: Santos
authors.forename: L
authors.initials: L
authors.lastname: Esmaili
authors.forename: S T
authors.initials: ST
authors.lastname: Fu
authors.forename: B E
authors.initials: BE
authors.lastname: Dwyer
mesh_terms: D000818:Animals; D016375:Antisense Elements (Genetics) / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002277:Carcinoma; D016923:Cell Death; D004268:DNA-Binding Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D018869:Heat-Shock Response; D006801:Humans; D012313:RNA / Q000378:metabolism; D051381:Rats; D013696:Temperature; D014157:Transcription Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D016375:Antisense Elements (Genetics); D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; C000619709:Hsf1 protein, rat; D014157:Transcription Factors; D012313:RNA