A correlation between cancer metastases and the fluidity of cancer cell membrane

Male Donryu rats weighing from 100 to 120 g were transplanted with AH100B, AH66F or Yoshida sarcoma (YS) cells intraperitoneally. After collecting ascites, while not bloody, the cancer cells were washed three times with Dulbecco's phosphate buffered saline (PBS) without Ca++ and Mg++ (pH 7.2). Then, each sediment was suspended in PBS mentioned above. Each suspension in which 10 million of cancer cells were contained was violently vibrated with a definite amount of 5-doxyl stearic acid and spin labeling of cancer cell membrane was done. Furthermore, each specimen thus obtained was subjected to measurements of ESR spectra and the order parameter was determined from the spectra. The order parameter of AH100B was the highest and that of YS the lowest at each temperature measured from 5 degrees C to 35 degrees C. YS cells have been reported to be found in blood stream within 24 hr, AH66F cells in a day and AH100B cells in 10 days or more after intraperitoneal inoculation. The results obtained here suggest that the accelerated fluidity of cancer cell membrane is related with the cancer metastasis.