Human prostatic carcinoma cell lines display altered regulation of polyamine transport in response to polyamine analogs and inhibitors
✍ Scribed by Mi, Z.; Kramer, D.L.; Miller, J.T.; Bergeron, R.J.; Bernacki, R.; Porter, C.W.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 203 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0270-4137
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✦ Synopsis
BACKGROUND. The possibility was investigated that complex homeostatic mechanisms which maintain polyamine pools in prostate-derived tumors may differ from those which are typically seen in other tissues and tumors. METHODS. Growth sensitivity and various regulatory responses were investigated in three human prostate carcinoma cell lines (LNCaP, DU145, and PC-3) treated with the inhibitor of S-adenosylmethionine decarboxylase CGP-48664 or the polyamine analog N 1 ,N 11diethylnorspermine (DENSPM), both of which are currently undergoing phase I clinical trial. RESULTS. Prostate tumor cell lines were all similarly growth-inhibited by the inhibitor CGP-48664 (IC 50 values, 1-5 M at 72 hr), but varied considerably in their sensitivity to DENSPM. The rank-order for cell-line growth inhibition by the analog was DU145 > PC-3 > LNCaP, with IC 50 values of 1, 30, and 1,000 M, respectively. Both compounds depleted intracellular polyamine pools to levels which seemed sufficient to account for inhibition of cell growth. While polyamine enzyme regulatory responses to both CGP-48664 and DENSPM were typical of those seen in other cell types, regulation of polyamine transport differed distinctly. Based on V max determinations, LNCaP cells failed to upregulate transport in response to CGP-48664, while PC-3 and LNCaP cells failed to downregulate transport in response to DENSPM. CONCLUSIONS. Relative to other cell lines, polyamine transport in prostate carcinoma cell lines was found to be uniquely insensitive to regulation by polyamines or analogs. Although this did not seem to correlate with growth sensitivity to polyamine analogs in vitro, it should be therapeutically exploitable in in vivo systems.