EFFECT OF HYPERTHERMIA ON CISPLATIN SENSITIVITY IN HUMAN GLIOMA AND OVARIAN-CARCINOMA CELL-LINES RESISTANT AND SENSITIVE TO CISPLATIN TREATMENT

Two pairs of human tumour-cell lines consisting of a cisplatin sensiti ve and resistant line from glioma and ovarian carcinoma were tested to determine the effect of hyperthermia on cisplatin sensitization. Both cisplatin resistant lines were more sensitive to 42 degrees C heating than their cisplatin sensitive counterparts. The cisplatin response w as dependent on cell growth phase, with plateau phase cells more sensi tive than exponentially growing cells. The difference in cisplatin res ponse between resistant and sensitive lines was also growth phase depe ndent and was opposite for the two cell line pairs. Hyperthermia cause d about the same thermal sensitization in the plateau phase cisplatin sensitive cell lines and in the resistant lines but this too was growt h-phase dependent. In exponentially growing cells hyperthermia-cisplat in sensitization was greater in the sensitive cell lines. Hyperthermia at 42 degrees C did not completely overcome cisplatin resistance but could be useful as a sensitizer in cisplatin resistant tumour cells.