Open AccessHyperthermic Enhancement of Cytotoxicity and Increased Uptake of cis ‐Diamminedichloroplatinum(II) in Cultured Human Esophageal Cancer Cells
Author(s) -
Miyahara Tokiharu,
Ueda Kunihiro,
Akaboshi Mitsuhiko,
Shimada Yutaka,
Imamura Masayuki,
Utsumi Hiroshi
Publication year - 1993
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1993.tb02875.x
Subject(s) - cytotoxicity , hyperthermia , cisplatin , cancer research , chemotherapy , chemistry , pharmacology , in vivo , dna , in vitro , biochemistry , biology , microbiology and biotechnology , medicine
Thermal enhancement of cytotoxicity of cis ‐diamminedichloroplatinum(II) (CDDP) has been well recognized and applied clinically to chemotherapy of various malignancies, but its fundamental mechanism remains to be elucidated. In order to obtain a clue to this mechanism, we analyzed the effect of hyperthermia on the uptake and subsequent distribution of [ 195m Pt]CDDP in two lines of esophageal cancer cells (KYSE‐150 and KYSE‐170) established from clinical patients. First, we observed a significant increase in [ 195m Pt]CDDP uptake by both types of cells at increasingly higher temperatures. The incorporated CDDP was distributed between the nucleus and the cytosol at a ratio of approximately 3:1, and the ratio remained the same at various temperatures. The CDDP was found in all four molecular fractions, i.e., DNA, RNA, protein, and TCA‐soluble, with a slight preference for DNA at higher temperatures. Enhancement of cytotoxicity required simultaneous, and not sequential, treatments with CDDP and hyperthermia; hyperthermia after CDDP treatment increased the efflux of CDDP from the cells, and rather reduced the cytotoxicity of CDDP. These results suggest that thermal enhancement of the cytotoxicity of CDDP is caused mainly by acceleration of the drug entry into the cell, probably due to increased permeability, and a consequent increase in the amount of CDDP binding to DNA. This mechanism gives support for clinical trial of simultaneous treatment with CDDP and hyperthermia.