Mobility of cells from solid tumors

The mobility of cells from two established cell lines of hamster origin, NIL B and its SV40 virus-transformant SV-NIL, was studied in cellular aggregates maintained in agitated liquid medium. Subcutaneous injection of 5 x 10(6) NIL B or SV-NIL cells into Syrian hamsters resulted in a high frequency of tumor formation - 1.00 for SV-NIL cells and 0.93 for NIL B cells. Cells from five different tumors of NIL B origin were grown in tissue culture and their mobility in cellular aggregates was also studied. The mobilities of the tumor-derived cells were similar to each other and to that of the SV-NIL cells, but slightly higher than that of the NIL B cells. In addition, the plating efficiency, saturation density and doubling time of NIL B, SV-NIL and the tumor-derived cells were determined in conventional flat culture. No consistent pattern of saturation density or doubling time was observed in the tumor-derived cells with respect to each other or to the established lines; however, the plating efficiencies of the tumor-derived cells were all considerably lower than those of NIL B and SV-NIL cells. It was concluded that selection for the ability to divide and survive in vivo (i.e. to form tumors) was accompanied by a modest increase in cell mobility in vitro.