Chronomodulation of topotecan or X-radiation treatment increases treatment efficacy without enhancing acute toxicity.

Purpose: Topotecan (TPT), a camptothecin analog, is currently used to treat human ovarian and small-cell lung cancer and is in clinical trials for other tumor sites. However, it is unknown whether chronomodulation of TPT treatment is beneficial. We examined the effects of administering TPT or X-radiation (XR) alone at different times of the day or night.

Effects of N1, N13-diethylnorspermine (DENSPM) and X-radiation treatment on human colorectal tumor clones with varying X-radiation and drug responses.

This study was designed to examine the effects of treatment with N1, N13-diethylnorspermine (DENSPM), a spermine analog, and X radiation on survival and on the polyamine and spermidine/spermine N1-acetyltransferase (SSAT) levels in closely related human colorectal tumor (HCT116) clones exhibiting a wide range of X-radiation and drug responses. After treatment with DENSPM and X radiation, clonogenic cell survival was measured. SSAT protein levels were measured by Western blot analysis and SSAT enzymatic activities by the conversion of [1-14C]acetyl-CoA into [1-14C]acetylspermidine.