Apigenin Inhibits Human SW620 Cell Growth by Targeting Polyamine Catabolism

Figure 1

Polyamine metabolism. Ornithine decarboxylase (ODC) is required for the first step of polyamine synthesis in which ornithine is decarboxylated to produce putrescine. In turn, putrescine is converted sequentially to spermidine and spermine by the action of adenosylmethionine decarboxylase and spermidine and spermine synthases, respectively. The conversion to lower level polyamines is made in either two steps, by the spermidine/spermine N¹-acetyltransferase (SSAT)/N¹-acetylpolyamine oxidase (APAO) mechanism, or directly from spermine to spermidine by spermine oxidase (SMO). The activities of both APAO and SMO lead to the production of H₂O₂ and aldehydes 3-acetoaminopropanal (3-AAP) and 3-aminopropanal (3-AP).