This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bernhard, E. J. Articles by Brown, J. M. Search for Related Content PubMed PubMed Citation Articles by Bernhard, E. J. Articles by Brown, J. M.

Re-Evaluating Gadolinium(III) Texaphyrin as a Radiosensitizing Agent¹

University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania 19104 [E. J. B., D. I. R.]; Radiation Biology Branch, Division of Clinical Sciences, National Cancer Institute, Bethesda, Maryland 20892 [J. B. M.]; Brain Tumor Research Center, University of California San Francisco, San Francisco, California 94143 [D. D., M. C.]; and Stanford University School of Medicine, Department of Radiation Oncology, Stanford, California 94305 [J. M. B.]

Gadolinium(III) texaphyrin (Gd-tex) was recently proposed as a radiosensitizing agent that combines preferential tumor uptake with detection of drug localization by magnetic resonance imaging (S. W. Young et al., Proc. Natl. Acad. Sci. USA, 93: 6610–6615, 1996). In view of the initial report on this compound, four radiobiology laboratories undertook independent efforts to further study radiosensitization by Gd-tex. In addition to repeating the previously reported studies on Gd-tex in HT-29 cells, we tested five other human tumor cell lines (U-87 MG, U251-NCI, SW480, A549, and MCF-7). These studies included a Gd-tex treatment period of 24 h before irradiation (as in the original publication), with concentrations of Gd-tex ranging from 20–500 µM. In neither the HT-29 cells nor any of the other five human cell lines did we see radiation sensitization by Gd-tex. Two cell lines (MCF-7 and U-87 MG) were further tested for radiosensitization by Gd-tex under hypoxic conditions. No radiosensitization was observed in either case. Finally, the radiation response of two tumor lines were assessed in vivo. Neither HT-29 xenografts in severe combined immunodeficient (SCID) mice nor RIF-1 tumors growing in C3H mice demonstrated radiosensitization after Gd-tex treatment before single or fractionated doses of radiation. Our results raise questions about the efficacy of Gd-tex as a radiosensitizing agent.

This article has been cited by other articles:

				R. A. Miller, K. W. Woodburn, Q. Fan, I. Lee, D. Miles, G. Duran, B. Sikic, and D. Magda Motexafin Gadolinium: A Redox Active Drug That Enhances the Efficacy of Bleomycin and Doxorubicin Clin. Cancer Res., October 1, 2001; 7(10): 3215 - 3221. [Abstract] [Full Text] [PDF]

				G. De Stasio, P. Casalbore, R. Pallini, B. Gilbert, F. Sanita, M. T. Ciotti, G. Rosi, A. Festinesi, L. M. Larocca, A. Rinelli, et al. Gadolinium in Human Glioblastoma Cells for Gadolinium Neutron Capture Therapy Cancer Res., May 15, 2001; 61(10): 4272 - 4277. [Abstract] [Full Text] [PDF]