Heat-shock protein expression in leukemia.

Heat-shock proteins (Hsps) are thought to play a role in the development of cancer and to modulate tumor response to cytotoxic therapy. In this study, Hsp27, Hsp60, Hsp90α, and HspBP1 gene expression was investigated in human leukemia cell lines as well as in leukemia cells derived from patients with the onset of the disease. Hsp70 membrane expression and expression of Hsp27, Hsp60, Hsp70, Hsp90α, and HspBP1 genes were also tested in samples from leukemia patients. Relative Hsps gene expression was examined in human leukemia cell lines and also in patients, using real-time quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). Hsp70 cell surface expression was studied in patients with leukemia onset using flow cytometry. All tested cell lines showed significantly increased expression of Hsp60, Hsp90α, and HspBP1 genes compared with a cohort of healthy controls; additionally there was increased Hsp27 expression except for Jurkat and CCRF cells. Significantly higher gene expression of Hsp27, Hsp60, Hsp90α, and HspBP1 was observed in the peripheral blood of patients compared with bone marrow and healthy control samples, while Hsp70 expression was without any significant difference among cohorts. Hsp70 cell surface expression was found on defrosted and cultured leukemia cells but not on unprocessed biological samples from patients. Leukemia cells showed a heterogeneous pattern of Hsp gene expression among leukemia cell lines as well as in peripheral blood and bone marrow of patients.