Cure of Fisher rats bearing radioresistant F98 glioma treated with cis-platinum and irradiated with monochromatic synchrotron X-rays.
High-grade gliomas are usually of poor prognosis, and conventional radiotherapy, even combined with chemotherapy, still fails to improve the survival of patients. Here, we propose an innovative therapeutic approach combining synchrotron radiation with cis-diamminedichloroplatinum (II) (CDDP). As suggested previously, monochromatic synchrotron irradiation of CDDP at 78.8 keV, just above the 78.4 keV platinum absorption K-edge, leads to an enhanced photoelectric effect and an increased local toxicity. To select a particular radiation energy that could provide supra-additive effect, we used pulsed-field gel electrophoresis to assess yields of DNA double-strand breaks induced in rat F98 glioma cells after CDDP treatment combined with synchrotron X-rays. Thereafter, intracerebral CDDP injection combined with synchrotron X-rays was applied to Fisher rats bearing F98 glioma. CDDP concentrations were mapped by synchrotron X-ray microfluorescence. An extra number of more slowly repaired double strand breaks were observed when irradiating CDDP-treated F98 cells at 78.8 keV. In vivo treatments were then performed with different radiation doses and CDDP concentrations. All cell inoculations in rat brain resulted in tumor development, and tumor presence was controlled by computed tomography. Among all of the conditions tested, the combination of 3 micro g of CDDP with 15 Gy resulted in the largest median survival time (206 days). After 1 year, about 34% of treated rats were still alive. This preclinical finding, validated by molecular analysis, represents the most protracted survival reported with this radioresistant glioma model and demonstrates the interest in powerful monochromatic X-ray sources as new tools for cancer treatments.
Biston
Marie-Claude
MC
U647 Institut National de la Santé et de la Recherche Médicale Rayonnement Synchrotron et Recherche Médicale, ID17 Medical Beamline and ID22 Beamline, European Synchrotron Radiation Facility, Grenoble, France.
Joubert
Aurélie
A
Adam
Jean-François
JF
Elleaume
Hélène
H
Bohic
Sylvain
S
Charvet
Anne-Marie
AM
Estève
François
F
Foray
Nicolas
N
Balosso
Jacques
J
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy*; D002945:Cisplatin / Q000494:pharmacology*; D003131:Combined Modality Therapy; D004249:DNA Damage; D004260:DNA Repair; D004273:DNA, Neoplasm / Q000187:drug effects / Q000528:radiation effects; D005910:Glioma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D011836:Radiation Tolerance; D051381:Rats; D011916:Rats, Inbred F344; D017356:Synchrotrons; D014965:X-Rays
D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D002945:Cisplatin