DNA transfection affects the metastatic capacity of tumour cells.

A rat rhabdomyosarcoma clonal line RMS/8 was cotransfected with genomic DNA of procaryotic or eucaryotic origin and neomycin resistance plasmid pKOneo. The lung colonizing and metastatic capacity of transfected cells was evaluated. When col- meta- RMS/8 cells were transfected, an increase in lung colonizing but not in metastatic ability was observed. The DNA transfection of col+ meta- RMS/8 cells led to an enhancement of metastatic potential. These effects were independent of the origin of donor genomic DNA but were closely related to the transfection efficiency. It is suggested that DNA transfection destabilized the recipient genome, thus leading to an increased heterogeneity which potentially favours metastasis. The mock-transfected col+ meta- RMS/8 cells also exhibited an increased metastatic capacity. The non-specific effects of DNA transfection and of transfection procedure per se should therefore be taken into account in gene transfer studies of metastasis.