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Targeted cytotoxic somatostatin analogue AN-238 inhibits somatostatin receptor-positive experimental colon cancers independently of their p53 status.

Publication ,  Journal Article
Szepeshazi, K; Schally, AV; Halmos, G; Armatis, P; Hebert, F; Sun, B; Feil, A; Kiaris, H; Nagy, A
Published in: Cancer Res
February 1, 2002

The resistance of advanced colorectal cancers to therapy is often related to mutations in the p53 tumor suppressor gene. Because somatostatin (SRIF) receptors (ssts) are present in colorectal carcinomas, the treatment with targeted cytotoxic SRIF analogue AN-238, consisting of 2-pyrrolinodoxorubicin (AN-201) linked to octapeptide SRIF carrier RC-121, may overcome this resistance by producing a higher concentration of the cytotoxic agent in the tumors. Four colon cancer cell lines, HCT-116 and LoVo expressing wild-type p53, and HCT-15 and HT-29 with mutated p53, were investigated. HCT-116, HCT-15, and HT-29, but not LoVo possess functional ssts. We analyzed changes in p53, p21, and proliferating cell nuclear antigen (PCNA) concentrations in these cells in vitro by immunoblotting after exposure to AN-238, its radical AN-201, or doxorubicin (DOX). Equitoxic doses of AN-238, AN-201, or DOX affected p53, p21, and PCNA differently. Analysis of the p21:p53 ratios revealed that DOX increased p53 levels, but most of p53 was mutated and inactive, whereas AN-238 produced smaller changes in p53 concentrations but enhanced its activity. In HCT-15 cells, PCNA:p21 ratios, which are indicators of proliferation and repair processes, remained unchanged after exposure to AN-238 but were increased by DOX. In vivo studies in nude mice demonstrated that AN-238, AN-201, and DOX were equally effective on HCT-116 tumors that express wild-type p53. However, AN-238 also inhibited the growth of HCT-15 and HT-29 cancers that express mutant p53, whereas AN-201 and DOX showed no effect. None of the compounds could suppress the proliferation of LoVo tumors that lack functional ssts. In conclusion, cytotoxic SRIF analogue AN-238 inhibits the growth of experimental colon cancers that express ssts, regardless of their p53 status.

Duke Scholars

Published In

Cancer Res

ISSN

0008-5472

Publication Date

February 1, 2002

Volume

62

Issue

3

Start / End Page

781 / 788

Location

United States

Related Subject Headings

  • Tumor Suppressor Protein p53
  • Tumor Cells, Cultured
  • Receptors, Somatostatin
  • RNA, Messenger
  • Pyrroles
  • Proliferating Cell Nuclear Antigen
  • Oncology & Carcinogenesis
  • Mutation
  • Mice, Nude
  • Mice
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Szepeshazi, K., Schally, A. V., Halmos, G., Armatis, P., Hebert, F., Sun, B., … Nagy, A. (2002). Targeted cytotoxic somatostatin analogue AN-238 inhibits somatostatin receptor-positive experimental colon cancers independently of their p53 status. Cancer Res, 62(3), 781–788.
Szepeshazi, Karoly, Andrew V. Schally, Gabor Halmos, Patricia Armatis, Francine Hebert, Baodong Sun, Anita Feil, Hippokratis Kiaris, and Attila Nagy. “Targeted cytotoxic somatostatin analogue AN-238 inhibits somatostatin receptor-positive experimental colon cancers independently of their p53 status.Cancer Res 62, no. 3 (February 1, 2002): 781–88.
Szepeshazi K, Schally AV, Halmos G, Armatis P, Hebert F, Sun B, et al. Targeted cytotoxic somatostatin analogue AN-238 inhibits somatostatin receptor-positive experimental colon cancers independently of their p53 status. Cancer Res. 2002 Feb 1;62(3):781–8.
Szepeshazi K, Schally AV, Halmos G, Armatis P, Hebert F, Sun B, Feil A, Kiaris H, Nagy A. Targeted cytotoxic somatostatin analogue AN-238 inhibits somatostatin receptor-positive experimental colon cancers independently of their p53 status. Cancer Res. 2002 Feb 1;62(3):781–788.

Published In

Cancer Res

ISSN

0008-5472

Publication Date

February 1, 2002

Volume

62

Issue

3

Start / End Page

781 / 788

Location

United States

Related Subject Headings

  • Tumor Suppressor Protein p53
  • Tumor Cells, Cultured
  • Receptors, Somatostatin
  • RNA, Messenger
  • Pyrroles
  • Proliferating Cell Nuclear Antigen
  • Oncology & Carcinogenesis
  • Mutation
  • Mice, Nude
  • Mice