Effects of antineoplastic agents on cytoplasmic and membrane-bound heat shock protein 70 (Hsp70) levels.
Here we report on the study of the effects of different antineoplastic agents, including cytarabine, 4-hydroperoxyifosfamide, the activated form of ifosfamide, vincristine, and paclitaxel, with regard to their capacity to modulate the amount of cytoplasmic and membrane-bound heat shock protein 70 (Hsp70). Hsp70 levels were measured in the myelogenous leukemic cell line K562, in the human colon carcinoma cell line CX2, and in peripheral blood lymphocytes (PBL) under physiological conditions (37 degrees C), and following non-lethal heat shock at 41.8 degrees C. A concentration of 1 microM and an incubation period of 2 h were determined as non-lethal, since none of the different antineoplastic agents induced necrosis or apoptosis in untreated or heat-shocked cells under these conditions. Our results show that tubulin-interacting agents, including vincristine and paclitaxel, but not DNA-interacting agents, including cytarabine and ifosfamide, selectively increase the amount of cytoplasmic Hsp70 in tumor and normal cells, as measured by semi-quantitative Western blot analysis. Mechanistically, a vincristine- and paclitaxel-induced tubulin assembly, as demonstrated by immunofluorescence microscopy, might be responsible for the elevated cytoplasmic Hsp70 levels. Interestingly, an increased membrane expression of Hsp70 following treatment with vincristine or paclitaxel was selectively observed on tumor cells, but not on normal cells.
Gehrmann
Mathias
M
Department of Hematology and Oncology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, D-93053 Regensburg, Germany
Pfister
Karin
K
Hutzler
Peter
P
Gastpar
Robert
R
Margulis
Boris
B
Multhoff
Gabriele
G
D017302:Annexins / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D020014:K562 Cells; D008856:Microscopy, Fluorescence; D017239:Paclitaxel / Q000494:pharmacology; D013696:Temperature; D014404:Tubulin / Q000378:metabolism; D014750:Vincristine / Q000494:pharmacology
D017302:Annexins; D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D005456:Fluorescent Dyes; D018840:HSP70 Heat-Shock Proteins; D014404:Tubulin; D014750:Vincristine; D016650:Fluorescein-5-isothiocyanate; D017239:Paclitaxel