Immunohistochemical staining of human spermidine/spermine N1-acetyltransferase superinduced in response to treatment with antitumor polyamine analogues.

A superinduction of the polyamine catabolic enzyme, spermidine/spermine N1-acetyltransferase (SSAT) accompanies the phenotype-specific cytotoxic response to a class of antitumor polyamine analogues in several important human solid tumor models. A highly specific antiserum against the human SSAT protein has been developed. Using this antiserum we demonstrate that polyamine analogue treatment in vitro or in vivo results in an induction of SSAT protein which is uniformly distributed throughout the cytoplasm of treated tumor cells. This new biochemical tool will be useful in the examination of the association of superinduced SSAT activity and cell type-specific cytotoxicity. Additionally, since clinical trials have begun on one of the SSAT-inducing polyamine analogues, this antiserum may be useful as a diagnostic tool in differentiating responsive and nonresponsive tumor cell populations in treated patients.