EFFECT OF HYPERTHERMIA AND TRANSFORMING G ROWTH-FACTORS ON THE EXPRESSION OF TRANSFORMED PHENOTYPE IN HUMAN CARCINOMA-CELLS

The action of hyperthermia (44 degrees C, 30 min) on the expression of transformed phenotype (anchorage-independent growth in 0.33% agar cul ture medium) in two lines of human tumor cells (lung carcinoma - A-549 and larynx carcinoma - HEp-2) was studied. It was found that heat tre atment considerably blocked the anchorage-independent proliferation of both wild-type and HIV tat gene-transfected HEp-2 cells which produce d TGF-alpha-immunoreactive factor(s). Exogenously added TGF-beta and/o r EGF (TGF-alpha analogue) did not change this antiproliferative effec t of hyperthermia when both human carcinoma cells of A-549 sing and di fferent clones of HIV tat-transfected HEp-2 cells were studied 2 h aft er the stop of hyperthermia action. it was shown that the Inhibitory e ffect of hyperthermia on the growth of HEp-2 cells was much less expre ssed 24 h after the stop of heat shock action. in this case TGF-beta a nd EGF considerably influenced the hyperthermia action era the cellula r growth. TGF-beta suppressed the expression of the transformed phenot ype in the tested cells while EGF increased this expression. Thus, hea t treatment can suppress the expression of transformed phenotype in ca rcinoma cells of human respiratory organs. This effect of hyperthermia is very strong 2 h after the termination of hyperthermia action and b ecomes considerably weaker after a 24 h period of cellular restoration .