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 using a transfection approach. Stably transfected MCF-7 breast cancer cells overproducing SAMDC (~5-fold) manifested reduced ornithine decarboxylase while levels of N′-spermidine/spermine acetyltransferase were variably increased. Analysis of cellular polyamine profile showed that spermine was selectively increased (~80%), while spermidine and putrescine levels were reduced (~48% and ~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 phenotype to breast cancer cells.