An anti-cancer drug compound comprises an spermidine/spermine N-acetyltransferase substrate. The spermidine/spermine N-acetyltransferase substrate may be a monoamine. The spermidine/spermine N-acetyltransferase substrate may be amantadine, rimantadine, dopamine or L-DOPA. A method of treating cancer comprises the use of an spermidine/spermine N-acetyltransferase substrate to treat cancer. The spermidine/spermine N-acetyltransferase substrate may be a monoamine. The spermidine/spermine N-acetyltransferase substrate may be amantadine, rimantadine, dopamine or L-DOPA.