Pierre Verrelle

Phase III randomized trial of very accelerated radiation therapy compared with conventional radiation therapy in squamous cell head and neck cancer: a GORTEC trial.

PURPOSE With the aim to increase the dose intensity of radiation therapy (RT), and subsequently the locoregional control rate, a very accelerated RT regimen was compared with conventional RT in a series of patients with head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS Between 1994 and 1998, 268 patients with T3 or T4, N0 to N3 HNSCC (staged by 1997 International Union Against Cancer criteria) that was not eligible for surgery were randomly assigned to receive either conventional RT, delivering 70 Gy in 7 weeks to the primary tumor and 35 fractions of 2 Gy over 49 days, or to receive very accelerated RT, delivering 62 to 64 Gy in 31 to 32 fractions of 2 Gy over 22 to 23 days (2 Gy/fraction bid). RESULTS The most common tumor site was the oropharynx and most of the patients (70%) had T4 and N1 to N3 tumors in 72% of patients. The main patient and tumor characteristics were well-balanced between the two arms. The median total doses were 63 Gy (accelerated) and 70 Gy (conventional), with a median overall time of 22 days and 48 days, respectively. Acute mucositis was markedly increased in the accelerated-RT arm (P < .001). The locoregional control rate was improved by 24% at 6 years with accelerated RT. In contrast, disease-free survival and overall survival were not significantly different between the two arms. There was no difference in late effects between the two arms. CONCLUSION The very accelerated RT regimen was feasible and provided a major benefit in locoregional control but had a modest effect on survival.

O6‐methylguanine‐DNA methyltransferase gene (MGMT) expression in human glioblastomas in relation to patient characteristics and p53 accumulation

Repair of cytotoxic DNA damage by O6‐methylguanine‐DNA methyltransferase (MGMT) is a potentially important factor of chemoresistance to chloroethylnitrosoureas (CENUs), commonly used in the treatment of glioblastoma multiforme (GBM). The value of p53 as a prognostic factor in GBMs remains unclear, but a possible relationship between MGMT gene expression and p53 has been suggested. To further examine these GBM characteristics in vivo, we assessed MGMT gene expression using semi‐quantitative RT‐PCR and p53 alteration by immuno‐histochemistry on a series of 39 GBMs. MGMT gene expression was inversely correlated with age (p < 0.03), consistent with the results of others. Interestingly, tumors from male patients had higher MGMT mRNA amounts than tumors from female patients (p < 0.03). No prognostic implication was observed either for MGMT gene expression or for p53 accumulation. However, MGMT gene expression was significantly lower in p53‐altered GBM, regardless of the percentage of positive cells (p < 0.01). Our observation suggests that in human glial tumors, a low level of MGMT gene expression might promote p53 alteration, probably via mutation of its gene. Int. J. Cancer (Pred. Oncol.) 84:416–420, 1999.

Akt signaling pathway: a target for radiosensitizing human malignant glioma

Radiation therapy plays a central role in the treatment of glioblastoma, but it is not curative due to the high tumor radioresistance. Phosphatidyl-inositol 3-kinase/protein kinase B (Akt) and Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathways serve to block the apoptosis process, keeping cells alive in very toxic environments such as chemotherapy or ionizing radiation. In the present study, from a panel of 8 human malignant glioma cell lines, investigations on the relationship between intrinsic radioresistance and Akt or STAT3 basal activation were done. Secondly, the impact of down-modulation of Akt or STAT3 signaling on in vitro intrinsic radiosensitivity was evaluated. Using a clonogenic cell survival assay, our results revealed a significant correlation between the basal Akt activation and the surviving fraction at 2 Gy (SF2). In contrast, no correlation was found between STAT3 activation and SF2. According to this, down-modulation of Akt with a specific chemical inhibitor (Akt inhibitor IV) demonstrated a significant enhancement of radiation sensitivity on glioma cells in a clonogenic survival assay. On the contrary, down-modulation of STAT3 signaling with a specific chemical inhibitor (JSI-124) or a neutralizing gp130 antibody failed to radiosensitize glioma cells. These data indicate that the Akt intercept node could be a more relevant therapeutic target than STAT3 for radiosensitizing human malignant glioma.

Randomized phase III trial (GORTEC 98-03) comparing re-irradiation plus chemotherapy versus methotrexate in patients with recurrent or a second primary head and neck squamous cell carcinoma, treated with a palliative intent

PURPOSE This randomized phase III trial investigated the potential benefit of concurrent re-irradiation, fluorouracil and hydroxyurea versus methotrexate for patients treated with palliative intent for recurrent or second primary head and neck squamous cell carcinoma (HNSCC) in previously irradiated area. PATIENTS AND METHODS Patients with recurrent HNSCC or a second primary not amenable to curative-intent treatment were randomized to the R-RT arm (concurrent re-irradiation, fluorouracil and hydroxyurea) or to the Ch-T arm (methotrexate). The primary endpoint was overall survival (OS). Due to a very slow accrual, the trial was closed after inclusion of 57 patients. RESULTS Fifty-seven patients were included. All patients died in the two arms with a maximal follow-up of 5years. Although four complete responses were achieved in R-RT arm, (none in Ch-T arm) re-irradiation did not improve OS compared with methotrexate (23% versus 22% at 1year, NS). Sixteen patients experienced clinical grade ⩾3 late toxicities (>6months), 11 in R-RT arm and five in Ch-T arm. CONCLUSIONS Premature discontinuation of the trial did not allow us to draw firm conclusions. However, there was no suggestion that concurrent re-irradiation, fluorouracil and hydroxyurea improved OS compared to methotrexate alone in patients treated with palliative intent for a recurrent or second primary HNSCC.

Phase III Trial of Protracted Compared With Split-Course Chemoradiation for Esophageal Carcinoma: Fédération Francophone de Cancérologie Digestive 9102

PURPOSE Chemoradiotherapy (CRT) is an alternative to surgery for resectable locally advanced esophageal carcinoma (RLA-EC). We investigated the heterogeneity of the treatment benefits across subgroups of patients, defined according to the radiation scheme. PATIENTS AND METHODS Between February 1993 and December 2000, 451 patients were enrolled. The following two schemes were allowed: protracted radiotherapy (P-RT), which scheduled 46 Gy over 4.5 weeks or split-course radiotherapy (SC-RT) with two 1-week courses of 15 Gy. Two courses of cisplatin and fluorouracil were delivered concomitantly. In case of exclusive CRT, a further course of 20 Gy over 2 weeks in the P-RT group and one 1-week course of 15 Gy in the SC-RT group were delivered with three courses of chemotherapy. SC-RT and P-RT were administered to 285 patients (64%) and 161 patients (36%), respectively. RESULTS For P-RT versus SC-RT, the response rate to induction CRT was 67% v 68%, respectively (P = .09), and 2-year local relapse-free survival rate was 76.7% v 56.8%, respectively (P = .002). Shorter tumor length and P-RT were associated with better local control in multivariate analysis (P = .002 for both). After a median follow-up time of 47.4 months, 2-year overall survival rate was 37.1% for P-RT compared with 30.5% for SC-RT (P = .25). Independent prognostic factors on survival were tumor diameter (P = .02), weight loss of 10% or less (P = .05), and response to induction CRT (P = .002). CONCLUSION Patients with RLA-EC treated with P-RT had better local control than patients treated with SC-RT. Response to induction CRT is a determinant prognostic factor on survival.

Influence of Nucleoshuttling of the ATM Protein in the Healthy Tissues Response to Radiation Therapy: Toward a Molecular Classification of Human Radiosensitivity

PURPOSE Whereas post-radiation therapy overreactions (OR) represent a clinical and societal issue, there is still no consensual radiobiological endpoint to predict clinical radiosensitivity. Since 2003, skin biopsy specimens have been collected from patients treated by radiation therapy against different tumor localizations and showing a wide range of OR. Here, we aimed to establish quantitative links between radiobiological factors and OR severity grades that would be relevant to radioresistant and genetic hyperradiosensitive cases. METHODS AND MATERIALS Immunofluorescence experiments were performed on a collection of skin fibroblasts from 12 radioresistant, 5 hyperradiosensitive, and 100 OR patients irradiated at 2 Gy. The numbers of micronuclei, γH2AX, and pATM foci that reflect different steps of DNA double-strand breaks (DSB) recognition and repair were assessed from 10 minutes to 24 hours after irradiation and plotted against the severity grades established by the Common Terminology Criteria for Adverse Events and the Radiation Therapy Oncology Group. RESULTS OR patients did not necessarily show a gross DSB repair defect but a systematic delay in the nucleoshuttling of the ATM protein required for complete DSB recognition. Among the radiobiological factors, the maximal number of pATM foci provided the best discrimination among OR patients and a significant correlation with each OR severity grade, independently of tumor localization and of the early or late nature of reactions. CONCLUSIONS Our results are consistent with a general classification of human radiosensitivity based on 3 groups: radioresistance (group I); moderate radiosensitivity caused by delay of nucleoshuttling of ATM, which includes OR patients (group II); and hyperradiosensitivity caused by a gross DSB repair defect, which includes fatal cases (group III).

Role of Akt in human malignant glioma: from oncogenesis to tumor aggressiveness.

Gathering evidence has revealed that Akt signaling pathway plays an important role in glioma progression and aggressiveness. Among Akt kinases the most studied, Akt1, has been involved in many cellular processes that are in favor of cell malignancy. More recently, the actions of the two other isoforms, Akt2 and Akt3 have emerged in glioma. After a description of Akt pathway activation, we will explore the role of each isoform in malignant glioma that strengthens the current preclinical and clinical studies evaluating the impact of Akt pathway targeting in glioblastomas.

Telomere Targeting with a New G4 Ligand Enhances Radiation-Induced Killing of Human Glioblastoma Cells

The aim of this study was to test in vitro the efficacy of TAC, an original G-quadruplex ligand, as a potential radiosensitizing agent for glioblastoma multiforme (GBM). Two human radioresistant telomerase-positive GBM cell lines (SF763 and SF767) were analyzed, with and without TAC treatment, for telomere length, cell proliferation, apoptosis, cell-cycle distribution, gene expression, cytogenetic aberrations, clonogenic survival assay, 53BP1 immunofluorescence staining, and γH2AX phosphorylation. We found that low concentrations of TAC (0.5 and 1 μmol/L) inhibited the proliferation of GBM cells in a concentration-dependent manner after only 1 week of treatment, with minimal effects on cell cycle and apoptosis. TAC treatment had no visible effect on average telomere length but modified expression levels of telomere-related genes (hTERT, TRF1, and TRF2) and induced concentration-dependent DNA damage response and dicentric chromosomes. Survival curves analysis showed that exposure to nontoxic, subapoptotic concentrations of TAC enhanced radiation-induced killing of GBM cells. Analysis of DNA repair after irradiation revealed delayed repair kinetics in GBM cells treated with TAC. Furthermore, the combined treatment (TAC and radiation) significantly increased the frequency of chromosomal aberrations as compared with radiation alone. These findings provide the first evidence that exposure to a G4 ligand radiosensitizes human glioblastoma cells and suggest the prospect of future therapeutic applications. Mol Cancer Ther; 10(10); 1784–95. ©2011 AACR.

Effects of Low-Dose Neutrons Applied at Reduced Dose Rate on Human Melanoma Cells

Abstract Dionet, C., Tchirkov, A., Alard, J-P., Arnold, J., Dhermain, J., Rapp, M., Bodez, V., Tamain, J-C., Monbel, I., Malet, P., Kwiatkowski, F., Donnarieix, D., Veyre, A. and Verrelle, P. Effects of Low-Dose Neutrons Applied at Reduced Dose Rate on Human Melanoma Cells. Human melanoma cells that are resistant to γ rays were irradiated with 14 MeV neutrons given at low doses ranging from 5 cGy to 1.12 Gy at a very low dose rate of 0.8 mGy min–1 or a moderate dose rate of 40 mGy min–1. The biological effects of neutrons were studied by two different methods: a cell survival assay after a 14-day incubation and an analysis of chromosomal aberrations in metaphases collected 20 h after irradiation. Unusual features of the survival curve at very low dose rate were a marked increase in cell killing at 5 cGy followed by a plateau for survival from 10 to 32.5 cGy. The levels of induced chromosomal aberrations showed a similar increase for both dose rates at 7.5 cGy and the existence of a plateau at the very low dose rate from 15 to 30 cGy. The existence of a plateau suggests that a repair process after low-dose neutrons might be induced after a threshold dose of 5–7.5 cGy which compensates for induced damage from doses as high as 32.5 cGy. These findings may be of interest for understanding the relative biological effectiveness of neutrons and the effects of environmental low-dose irradiation.

High incidence of cancer in a family segregating a mutation of the ATM gene: possible role of ATM heterozygosity in cancer.

ATM mutations predispose cells to malignancy by promoting chromosomal instability. We have identified a family with multiple cancers that segregates a mutant allele of ATM, IVS61+2insTA, which causes skipping of exon 61 in the mRNA, as well as a previously undescribed polymorphism, IVS61+104C(54):T(46). The mutation was inherited by two sisters, one who developed breast cancer at age 39 and the second at age 44, from their mother, who developed kidney cancer at age 67. Molecular studies were undertaken to determine the role of the ATM gene in the development of cancer in this family. Studies of irradiated lymphocytes from both sisters revealed elevated numbers of chromatid breaks, typical of A‐T heterozygotes. Studies on lymphoblastoid cell lines established from these individuals revealed abnormal p53 induction and apoptosis after DNA damage. Loss of heterozygosity (LOH) in the ATM region of chromosome 11q23.1 showed that the normal ATM allele was lost in the breast tumor of the older sister. LOH was not seen at the BRCA1 or BRCA2 loci. BRCA2 is not likely to be a cancer‐predisposing gene in this family because each sister inherited different chromosomes 13 from each parent. The sisters share their maternal BRCA1 allele, although no mutation in this gene was detected in the family. Our findings suggest that haploinsufficiency at ATM may promote tumorigenesis, even though LOH at the locus supports a more classic two‐hit tumor suppressor gene model. Hum Mutat 14:485–492, 1999.