Studies on the antitumor activity and biochemical actions of cyclopentenyl cytosine against human colon carcinoma HT-29 in vitro and in vivo

Kamran Gharehbaghi, Weining Zhen, Monika Fritzer-Szekeres, Thomas Szekeres, Hiremagalur N. Jayaram

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Cyclopentenyl cytosine (CPEC) is cytotoxic to several tumor cell lines. CPEC inhibits CTP synthesis resulting in depletion of cytidylate pools. The aim of this study was to examine CPEC's cytotoxic and antitumor activity in vitro and in vivo against human colon carcinoma HT-29, and to relate its action on CTP synthesis. CPEC exhibits potent cytotoxicity in vitro to HT-29 cells with an LC50 (concentration that is lethal to the survival of 50% cell colonies) of 2.4 μM and 0.46 μM following 2 h and 24 h exposure, respectively. Incubation of cells with CPEC for 2 h resulted in a dose- dependent decrease in cytidylate pools. The in vivo antitumor activity of CPEC in athymic mice transplanted subcutaneously (s.c) with 3 million HT-29 cells was examined. Antitumor activity of CPEC was elucidated in early- staged tumor, wherein CPEC (1.5 mg/kg, QD x 9 or 3 mg/kg, QOD x 9) was administered intraperitoneally (i.p.) 24 h after tumor implantation and it resulted in a significant reduction in tumor weight to 48% of control. The effect of CPEC on established solid tumors in vivo was examined in athymic mice transplanted s.c. 14 days earlier with HT-29 cells and treated i.p. with 1.5 mg/kg CPEC, QD x 5 for 4 courses, with a 10 day-interval between courses. This treatment resulted in a significant reduction in tumor weight (72%) in the treated group. HPLC analysis of HT-29 tumor obtained from mice after treatment with CPEC showed a depletion of the CTP concentration reaching a nadir at 8 h. In conclusion, the present studies demonstrate potent antitumor activity of CPEC against freshly transplanted and established human colon carcinoma which can be corroborated with the drug's biochemical actions.

Original languageEnglish
Pages (from-to)103-112
Number of pages10
JournalLife Sciences
Volume64
Issue number2
DOIs
StatePublished - Dec 4 1998

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cyclopentenyl cytosine
Colon
Carcinoma
Tumors
Cytidine Triphosphate
HT29 Cells
Tumor Burden
Nude Mice
Neoplasms
In Vitro Techniques
Cells

Keywords

  • Antitumor activity
  • CTP synthase inhibitor
  • Cyclopentenyl cytosine
  • Human colon carcinoma HT-29

ASJC Scopus subject areas

  • Pharmacology

Cite this

Studies on the antitumor activity and biochemical actions of cyclopentenyl cytosine against human colon carcinoma HT-29 in vitro and in vivo. / Gharehbaghi, Kamran; Zhen, Weining; Fritzer-Szekeres, Monika; Szekeres, Thomas; Jayaram, Hiremagalur N.

In: Life Sciences, Vol. 64, No. 2, 04.12.1998, p. 103-112.

Research output: Contribution to journalArticle

Gharehbaghi, Kamran ; Zhen, Weining ; Fritzer-Szekeres, Monika ; Szekeres, Thomas ; Jayaram, Hiremagalur N. / Studies on the antitumor activity and biochemical actions of cyclopentenyl cytosine against human colon carcinoma HT-29 in vitro and in vivo. In: Life Sciences. 1998 ; Vol. 64, No. 2. pp. 103-112.
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abstract = "Cyclopentenyl cytosine (CPEC) is cytotoxic to several tumor cell lines. CPEC inhibits CTP synthesis resulting in depletion of cytidylate pools. The aim of this study was to examine CPEC's cytotoxic and antitumor activity in vitro and in vivo against human colon carcinoma HT-29, and to relate its action on CTP synthesis. CPEC exhibits potent cytotoxicity in vitro to HT-29 cells with an LC50 (concentration that is lethal to the survival of 50{\%} cell colonies) of 2.4 μM and 0.46 μM following 2 h and 24 h exposure, respectively. Incubation of cells with CPEC for 2 h resulted in a dose- dependent decrease in cytidylate pools. The in vivo antitumor activity of CPEC in athymic mice transplanted subcutaneously (s.c) with 3 million HT-29 cells was examined. Antitumor activity of CPEC was elucidated in early- staged tumor, wherein CPEC (1.5 mg/kg, QD x 9 or 3 mg/kg, QOD x 9) was administered intraperitoneally (i.p.) 24 h after tumor implantation and it resulted in a significant reduction in tumor weight to 48{\%} of control. The effect of CPEC on established solid tumors in vivo was examined in athymic mice transplanted s.c. 14 days earlier with HT-29 cells and treated i.p. with 1.5 mg/kg CPEC, QD x 5 for 4 courses, with a 10 day-interval between courses. This treatment resulted in a significant reduction in tumor weight (72{\%}) in the treated group. HPLC analysis of HT-29 tumor obtained from mice after treatment with CPEC showed a depletion of the CTP concentration reaching a nadir at 8 h. In conclusion, the present studies demonstrate potent antitumor activity of CPEC against freshly transplanted and established human colon carcinoma which can be corroborated with the drug's biochemical actions.",
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