The anti-cancer drug cisplatin induces H25 in Ehrlich ascites tumor cells by a mechanism different from transcriptional stimulation influencing predominantly H25 translation.
Treatment of Ehrlich ascites tumor (EAT) cells with the anti-cancer drug cisplatin induces an increase of the intracellular level of the small heat shock protein Hsp25 without stimulating the general stress response. The mechanism of this induction process was investigated at the levels of gene transcription, protein synthesis and stability. We show that an increased synthesis of Hsp25 is predominantly responsible for the increased intracellular level of this protein. In addition, there is a slightly increased metabolic stability of Hsp25 in cisplatin-treated EAT cells. In contrast to the mechanism of Hsp25 induction by heat shock and other chemical stresses, stimulated synthesis of Hsp25 after treatment with cisplatin is not the result of increased transcription of the hsp25 gene. Cisplatin treatment does not significantly influence the oligomerization of heat shock transcription factors 1 and 2, hsp25 promoter activity or hsp25 mRNA stability, as judged by cross-linking experiments, reporter gene assay and Northern blot analysis. Hence, cisplatin specifically induces Hsp25 synthesis at the level of mRNA translation without any changes in hsp25 gene transcription.
Gotthardt
R
R
Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Neininger
A
A
Gaestel
M
M
D000818:Animals; D001483:Base Sequence; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism / Q000473:pathology*; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D002945:Cisplatin / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D017930:Genes, Reporter; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000378:metabolism; D051379:Mice; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects
D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C070389:HSF2 protein, human; D015500:Chloramphenicol O-Acetyltransferase; D002945:Cisplatin