Occurrence of Cytosolic Protein and Phosphoprotein Changes in Human Colon Tumor Cells with the Development of Resistance to Mitomycin C

Charles W. Taylor, Michael G. Brattain, Lynn C. Yeoman

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The cytosolic proteins and phosphoproteins of a mitomycin C-sensitive cell line were examined as progressively greater doses of mitomycin C were administered over a period of 44 weeks. Resistance of the human colon carcinoma cell line increased from a 50% inhibitory concentration of 1 to 6 over this time period. Changes in cytosolic protein patterns included increases in the amounts of three proteins with molecular weight x 10 apparent isoelectric point (Mr/pl) values of 56/6.2, 37/7.3, and 27/6.1. Analysis of in vitro 32P-labeled phosphoprotein patterns revealed reductions in the amounts of four proteins with Mr/pl values of 42/6.3,40/6.7, 31/6.3, and 25/6.1. One increase was detected in a phosphoprotein with a Mr/pl value of 33/6.1. These changes in cytosolic components paralleled the development of resistance to mitomycin C and may reflect changes in the clonal composition of the cell line as it becomes progressively more resistant to mitomycin C or changes in critical proteins or enzymes involved in the activation or biotransformation of the drug.

Original languageEnglish (US)
Pages (from-to)4422-4427
Number of pages6
JournalCancer Research
Volume45
Issue number9
StatePublished - Sep 1985

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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