Lasers in Medical Science

, Volume 10, Issue 1, pp 31–36 | Cite as

Laserthermia kills acidotic cancer cells more effectively than conventional hyperthermia

  • M. Castrén-Persons
Original Articles


The aim of this study was to investigate how acidosis affects the sensitivity of F9 embryonal carcinoma cells to conventionally induced hyperthermia and Nd-YAG laser-induced laserthermia. Nigericin, a polyether ionophore, was used to reduce the intracellular pH to 6.8, while the control cells were maintained at a physiological pH of 7.4. Acidosis increased the heat sensitivity significantly. After the water bath only 75% of the acidotic F9S1 cells were viable, whereas all of the control cells at pH 7.4 survived. When the laser was used, the difference was even more pronounced. Only 9% of the acidotic cells were viable after a 2-min treatment and 0.2% after a 4-min treatment. At physiological pH a 2-min treatment left 41% of the cells viable and a 4-min treatment 2%. This study showed that laserthermia is significantly more effective in killing cells with low intracellular pH than it is in killing cells with normal intracellular pH. The core of a tumour is often acidotic and thus radioresistant. It is suggested that laserthermia could be a good choice when treating acidotic radioresistant cancer cells, and its effect as an adjuvant to radiation therapy should be investigated.

Key words

Embryonal carcinoma F9 cells Laser Hyperthermia Nigericin Acidosis 


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Copyright information

© W.B. Saunders Company Ltd 1995

Authors and Affiliations

  • M. Castrén-Persons
    • 1
  1. 1.Second Department of Surgery and Department of PathologyUniversity of HelsinkiFinland

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