Regulation of HSP60 mRNA expression in a human ovarian carcinoma cell line.
The expression of the 60-kDa heat-shock protein (HSP60) varies markedly among patients with ovarian carcinoma, and high-level expression predicts poor survival in such patients treated with cisplatin (DDP)-containing chemotherapy programs. We investigated the expression of HSP60 in human ovarian carcinoma 2008 cells and an 11-fold DDP-resistant subline 2008/C13*5.25. Heating for 2 h at 44 degrees C produced a 2.7 +/- 0.16-fold increase (mean +/- SD) that was maximal at 4 h after the start of heat exposure. Exposure to an IC50 concentration of DDP for 1 h induced a 1.8 +/- 0.03-fold increase in hsp60 expression. The opposite was true for cadmium and zinc, both of which induced increases in metallothionein IIA but not in the hsp60 message. 2008/C13*5.25 cells constitutively over-expressed hsp60 mRNA by 1.7 +/- 0.16 orders of magnitude and contained a 3.8 +/- 0.45-fold higher level of HSP60 as detected by immunocytochemical staining. 2008/C13*5.25 cells showed 1.2-fold cross-resistance to thermal killing. Expression of hsp60 was markedly reduced in 2008 xenografts as compared with 2008 cells growing in vitro; however, neither serum starvation nor refeeding altered the message level. Exposure to a variety of growth factors and drug treatments known to alter the DDP sensitivity of 2008 cells, including epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, buthionine sulfoximine, ouabain, and forskolin, did not alter hsp60 expression. These results suggest a role for HSP60 in mediating resistance to both DDP and hyperthermia but indicate that the hsp60 mRNA levels are not regulated by the factors listed above.
Kimura
E
E
Department of Medicine, University of California, San Diego, La Jolla 92093-0812.
Enns
R E
RE
Thiebaut
F
F
Howell
S B
SB
D015152:Blotting, Northern; D002104:Cadmium / Q000494:pharmacology; D018834:Chaperonin 60; D002945:Cisplatin / Q000494:pharmacology*; D004351:Drug Resistance; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006133:Growth Substances / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D006358:Hot Temperature; D006801:Humans; D008668:Metallothionein / Q000378:metabolism; D009368:Neoplasm Transplantation; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012334:RNA, Neoplasm / Q000096:biosynthesis* / Q000235:genetics; D014407:Tumor Cells, Cultured; D015032:Zinc / Q000494:pharmacology
D018834:Chaperonin 60; D006133:Growth Substances; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D002104:Cadmium; D008668:Metallothionein; D015032:Zinc; D002945:Cisplatin