Effects of culture temperatures on radio- and thermosensitivity of human cancer cells.

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So far, most of the characteristics of cancer cells have been investigated through culturing at 37.0ﾟC. However, 37.0ﾟC is not always optimal temperature for the growth of cells or repairing damage induced by radiation or hyperthermia. In the treatment for cancer by radiation and other modalities, on the other hand, local control is one of the main purpose, in relevance to cell death. Another purpose pf the therapy may be the prevention and treatment of metastasis. So far, very few metastasis. models derived from human malignancies have been available. As for human lung cancer xenograft, both hematogenous and lymphatogenic route of metastasis has been observed in only one report. In this study, various radio- biological parameters of AOI cells, a cell line derived from human lung cancer, were examined at various culture temperatures, that is 35.0, 36.0, 37.0, 38.0 39.0ﾟC. Culture temperatures showed apparent influences on growth rate, cell density in the plateau phase, thermosensitivit … More ies and Elkind-Sutton type recovery in AOI cells. At 37.0ﾟC, X-ray survival curve in a semilogarithmic graph increased its slope as the doses increased. Moreover, feeder layer AOI cells (1.0- 20x 10^4/6cm petri dish) which were irradiated with 25Gy of X-rays showed a potent cytotoxicities on intact AOI cells at 37.0ﾟC. At 35.0ﾟC, the cytotoxicity of feeder layer was ten times as much as at 37.0ﾟC, while at 39.0ﾟC it was one tenth as much as at 37.0ﾟC. Conditioned media from the feeder layer did show a potent cytotoxic effects on intact AOI cells, irrespective of culture temperatures. So far, feeder layer has been regarded as a growth stimulant. In AOI cells, some toxic substances may be excreted from heavily X-irradiated cells. This cytotoxicity may not be attributed to chromosome aberrations induced by X-rays.When AOI tumors intradermally inoculated into hind legs of KSN nude mice reached 2.5cm in diameter, spontaneous multiple metastases were observed in 100% of the mice. The site of metastases included spleen, lung, kidney, liver and adrenal gland other than lymphnodes of various areas. Each metastatic foci were investigated both macroscopically and microscopically. ^<31>P spectra of AOI tumors were also investigated with MRS (BEM, 2T) after local X-irradiation and or hyperthermia. This system may be very useful for the study on both local control and metastasis of cancer. Less