ISOLATION AND CHARACTERIZATION OF HUMAN BREAST-CANCER CELLS OVEREXPRESSING S-ADENOSYLMETHIONINE DECARBOXYLASE

We report the first successful isolation and initial characterization of S-adenosylmethionine decarboxylase (SAMDC)-overexpressing cells usi ng a transfection approach. Stably transfected MCF-7 breast cancer cel ls overproducing SAMDC (similar to 5-fold) manifested reduced ornithin e decarboxylase while levels of N'-spermidine/spermine acetyltransfera se were variably increased. Analysis of cellular polyamine profile sho wed that spermine was selectively increased (similar to 80%), while sp ermidine and putrescine levels were reduced (similar to 48% and simila r to 15% of control, respectively). Since SAMDC-overexpressing clones exhibited increased clonogenicity in soft agar, our data suggest that spermine may be selectively involved in conferring a more invasive phe notype to breast cancer cells.