SMS 201-995 enhances S-phase block induced by 5-fluorouracil in a human colorectal cancer cell line

Anticancer Drugs. 2005 Oct;16(9):989-96. doi: 10.1097/01.cad.0000180118.93535.2b.

Abstract

The action of the somatostatin analog SMS-201.995 (SMS) was tested in monotherapy and in combined therapy with the cytotoxic agent 5-fluorouracil (5-FU) on cell cycle kinetics of the human colon cancer cell line WiDr, expressing a mutant p53 (mp53). The data, obtained by flow cytometric DNA analysis, showed that SMS at 0.2 microg/ml increased apoptosis, augmenting the proportion of cells with subdiploid DNA content by 65 and 48% after 3 and 6 h, respectively. In cultures lasting 24 and 36 h, it also decreased the percentages of cells in G0/G1 phase by 22.9 and 14.3%; whereas at a dose of 0.1 microg/ml, SMS decreased the percentage of cells in G2/M by 14.3%. In contrast to SMS, 5-FU (0.1 microg/ml) augmented the apoptosis at 12 h, and markedly increased the fraction of cells in S phase, increasing its value from 24 and 72 h by 108 and 234%, respectively, in comparison to the control. The most evident finding after the combination of SMS (0.2 microg/ml) and 5-FU (0.1 microg/ml) was a potentiation of 5-FU-induced S-phase block by a further 7.9, 12.9 and 42.1% at 24, 36 and 72 h, respectively. Treatment with 5-FU also upregulated HLA class I expression of the cancer cells. In this sense, SMS was less effective and when given in combination with 5-FU did not change the effects induced by 5-FU. The data emphasize that SMS exhibits pro-apoptotic and anti-proliferative effects, which in proper dose combinations might enhance the effects of 5-FU on human colorectal cancer cells expressing mp53.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Apoptosis / drug effects
  • Cell Cycle / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology
  • Colorectal Neoplasms / physiopathology
  • Dose-Response Relationship, Drug
  • Drug Synergism
  • Flow Cytometry
  • Fluorouracil / pharmacology*
  • Histocompatibility Antigens Class I / metabolism
  • Humans
  • Octreotide / pharmacology*
  • S Phase / drug effects*
  • Time Factors

Substances

  • Antineoplastic Agents
  • Histocompatibility Antigens Class I
  • Octreotide
  • Fluorouracil