The effect of tumor burden on ornithine decarboxylase activity in mice

Rami Saydjari, Robert W. Alexander, James R. Upp, Graeme J. Poston, Sam C. Barranco, Courtney M. Townsend, James C. Thompson

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Polyamines are essential for cell growth of normal and neoplastic tissue. αDifluoromethylornithine (DFMO) is a known irreversible inhibitor or ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis. The purpose of this study was to examine the effects of tumor burden on ODC in tissues of tumorbearing compared with tumor-free mice. Twenty-eight male Balb/c mice were divided into four groups of 7 each. Groups 1 and 2 were inoculated subcutaneously with 10 X 106 MC-26 mouse colon adenocarcinoma cells. Groups 3 and 4 were kept as tumor-free controls. Ten days after inoculation, groups 2 and 4 were injected with DFMO (200 mg/kg) intraperitoneally (IP) while Groups 1 and 3 received saline. Two hours after the injection of DFMO the animals were sacrificed. The tumor, pancreas, kidney, and liver were excised and analyzed for ODC activity. DFMO caused a significant reduction (compared with controls that did not receive DFMO) in the ODC activity of tumors; however, ODC activity of the kidney, pancreas, and liver of tumor-bearing mice was not affected. Additionally, the basal ODC activity in the kidney, liver, and pancreas of tumor-bearing mice was significantly lower compared with tumor-free controls. DFMO lowered ODC activity in the kidney, pancreas, and liver of tumor-free mice. These results suggest that the presence of MC-26 tumor causes systemic effects that alter ODC activity and the response to a known inhibitor of ODC.

Original languageEnglish (US)
Pages (from-to)415-419
Number of pages5
JournalCancer Investigation
Issue number4
StatePublished - 1991
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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