title: The role of heat shock protein 70 in the thermoresistance of prostate cancer cell line spheroids.
abstract: Heat shock protein 70 (Hsp70), a protein induced in cells exposed to sublethal heat shock, is present in all living cells and has been highly conserved during evolution. The aim of the current study was to determine the role of heat shock proteins in the resistance of prostate carcinoma cell line spheroids to hyperthermia. In vitro, the expression of Hsp70 by the DU 145 cell line, when cultured as monolayer or multicellular spheroids, was studied using Western blotting and enzyme-linked immunosorbent assay methods. The level of Hsp70 in spheroid cultures for up to 26 days at 37 degrees C remained similar to monolayer cultures. However, in samples treated with hyperthermia at 43 degrees C for 120 min, the spheroid cultures expressed a higher level of Hsp70 as compared to monolayer culture. Under similar conditions of heat treatment, the spheroids showed more heat resistance than monolayer cultures as judged by the number of colonies that they formed in suspension cultures. The results suggest that cells cultured in multicellular spheroids showed more heat resistance as compared to monolayer cultures by producing higher levels of Hsp70.
authors.affiliation: Laboratory of Biophysics and Molecular Biology, Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran, Iran.
authors.forename: Samideh
authors.initials: S
authors.lastname: Khoei
authors.forename: Bahram
authors.initials: B
authors.lastname: Goliaei
authors.forename: Ali
authors.initials: A
authors.lastname: Neshasteh-Riz
authors.forename: Abdolkhalegh
authors.initials: A
authors.lastname: Deizadji
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival; D005334:Fever; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D007700:Kinetics; D008297:Male; D014411:Neoplastic Stem Cells; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D018874:Spheroids, Cellular / Q000473:pathology*
chemical_list: D018840:HSP70 Heat-Shock Proteins