EFFECTS OF HYPERTHERMIA ON THE NUCLEOLAR PROTEINS IN TUMOR-CELLS

The effects of hyperthermia at 41-degrees-C and 43-degrees-C on the nu cleolar protein B23 in Ehrlich ascites tumour (EAT), human glioblastom a U-87 MG and U-373 MG cell lines were studied. Cellular localization of protein B23 was detected by an immunofluorescence technique using m onoclonal antibody against protein B23. Diminution of fluorescence in the nucleoli occurred when the cells were treated at high temperature. The decrease in fluorescence level depends on the treatment temperatu re and duration. Among the three cell lines studied, the U-373 MG glio blastoma was the least responsive to hyperthermia followed by the U-87 MG glioblastoma. The decrease in nucleolar fluorescence of the EAT ce lls treated at 41-degrees-C and 43-degrees-C correlated with their sub sequent cell survival. Dispersion of the nucleolar argyrophilic granul es occurred in EAT cells after heating at 43-degrees-C for 1 h. The po ssible implication of such effect is discussed in relation to the heat -sensitive elements in the nucleolus.