Changes in drug sensitivity of a human astrocytoma clone previously treated with 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea in vitro

Sam C. Barranco, Courtney M. Townsend, Vernon K. Jenkins, Steven K. Koester, Barbara Y. Ho, Karen J. Reumont

Research output: Contribution to journalArticle

3 Scopus citations


We have shown in earlier studies that repeated weekly exposures of a human astrocytoma clone (AST 3-4) to MeCCNU (10 μg/ml for 1 h per week) produced a linear decrease in survival over the first 3 weekly treatments. But, after that time these cells became progressively more resistant to the 10 μg/ml concentration of the agent. In the studies reported here we show that these previously treated cells were also less responsive to other doses ranging from 1 to 30 μg MeCCNU/ml. This change in sensitivity to MeCCNU was accompanied by collateral changes in response to other agents: resistance to BCNU and Galactitol, increased sensitivity to Adriamycin, and no change to ionizing radiation. These experiments suggest that once repeated treatments with a single agent cause a tumor cell population to become more resistant, sensitivity to other agents may also change unpredictably.

Original languageEnglish (US)
Pages (from-to)293-298
Number of pages6
JournalInvestigational New Drugs
Issue number4
StatePublished - Dec 1 1988



  • adriamycin
  • astrocytoma
  • drug resistance
  • nitrosourea
  • radiation

ASJC Scopus subject areas

  • Oncology
  • Pharmacology
  • Pharmacology (medical)

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