In vitro efficacy of carboplatin and hyperthermia in a murine retinoblastoma cell line

Timothy G. Murray, Nicole Cicciarelli, Cathleen M. McCabe, Bruce Ksander, William Feuer, Joyce Schiffman, William F. Mieler, Joan M. O'Brien

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35 Scopus citations

Abstract

Purpose. To determine the cell-killing activity of varying doses of carboplatin, graded hyperthermia, and the combination of carboplatin and hyperthermia in the treatment of a transgenic murine retinoblastoma cell line. Methods. Replicate cell wells (more than six wells per dose point) from an established transgenic murine retinoblastoma cell line (Rb-6) were exposed to a single application of hyperthermia for 15, 30, 60, and 120 minutes at temperatures of 37°C (control), 40°C, and 43°C. Carboplatin dose response treatment was studied at doses of 2000, 1000, 500, 400, 300, 200, 100, and 50 ng per well. Combined treatment studies used these carboplatin dosages with each of the graded hyperthermia exposure temperatures at each exposure time. At 24 hours, all wells were pulsed with 3H-thymidine for 24 hours, washed three times, harvested, and counted. Raw counts (3H-thymidine) were fitted to a linear regression model to calculate the lethal dose for 50% (LD50) of cells. Results. The LD50 for carboplatin exposure at 37°C occurred at 542 ng. The LD50 for hyperthermia at 40°C occurred at 90 minutes and at 43°C it occurred at 62 minutes. Combined hyperthermia and carboplatin exposure yielded a synergistic interaction with an LD50 of 327 ng at 43°C for 30 minutes. Determination of a thermal enhancement ratio yielded an enhancement range of 1.1 to 25.8. Conclusions. The synergistic cytocidal interaction of heat and carboplatin in a transgenic murine retinoblastoma cell line has been established in this study. The increased thermal enhancement ratio documents the potential utility of combined treatment applications in reducing treatment levels of single-modality therapy, potentially allowing for a decrease in treatment-related morbidity.

Original languageEnglish (US)
Pages (from-to)2516-2522
Number of pages7
JournalInvestigative Ophthalmology and Visual Science
Volume38
Issue number12
StatePublished - Nov 1 1997

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Keywords

  • Cell modeling
  • Chemotherapy
  • Hyperthermia
  • Retinoblastoma
  • Transgenic animals

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Murray, T. G., Cicciarelli, N., McCabe, C. M., Ksander, B., Feuer, W., Schiffman, J., Mieler, W. F., & O'Brien, J. M. (1997). In vitro efficacy of carboplatin and hyperthermia in a murine retinoblastoma cell line. Investigative Ophthalmology and Visual Science, 38(12), 2516-2522.