Early and late skin reactions to radiotherapy for breast cancer and their correlation with radiation-induced DNA damage in lymphocytes

INTRODUCTION Radiotherapy outcomes might be further improved by a greater understanding of the individual variations in normal tissue reactions that determine tolerance. Most published studies on radiation toxicity have been performed retrospectively. Our prospective study was launched in 1996 to measure the in vitro radiosensitivity of peripheral blood lymphocytes before treatment with radical radiotherapy in patients with breast cancer, and to assess the early and the late radiation skin side effects in the same group of patients. We prospectively recruited consecutive breast cancer patients receiving radiation therapy after breast surgery. To evaluate whether early and late side effects of radiotherapy can be predicted by the assay, a study was conducted of the association between the results of in vitro radiosensitivity tests and acute and late adverse radiation effects. METHODS Intrinsic molecular radiosensitivity was measured by using an initial radiation-induced DNA damage assay on lymphocytes obtained from breast cancer patients before radiotherapy. Acute reactions were assessed in 108 of these patients on the last treatment day. Late morbidity was assessed after 7 years of follow-up in some of these patients. The Radiation Therapy Oncology Group (RTOG) morbidity score system was used for both assessments. RESULTS Radiosensitivity values obtained using the in vitro test showed no relation with the acute or late adverse skin reactions observed. There was no evidence of a relation between acute and late normal tissue reactions assessed in the same patients. A positive relation was found between the treatment volume and both early and late side effects. CONCLUSION After radiation treatment, a number of cells containing major changes can have a long survival and disappear very slowly, becoming a chronic focus of immunological system stimulation. This stimulation can produce, in a stochastic manner, late radiation-related adverse effects of varying severity. Further research is warranted to identify the major determinants of normal tissue radiation response to make it possible to individualize treatments and improve the outcome of radiotherapy in cancer patients.

Molecular dissection of Arabidopsis thaliana endodermis development, structure and function

In vascular plants, the endodermis establishes a protective diffusion barrier surrounding the vasculature preventing the passive, uncontrolled entry of nutrients absorbed by the plant. It does so by means of a differentiation feature, the "Casparian Strip" (CS), a highly localized cell wall impregnation made of lignin, which seals the extracellular space. Although the existence of this differentiation feature has been intensively described, the mechanisms establishing this hallmark remain obscure. In this work I report, the developmental sequence of events that leads to a differentiated endodermis, in the plant model Arabidopsis thaliana. In addition, my descriptive approach gave important insights as to how these cells define membrane domains involved in the directional transport of nutrients. I also participated in characterizing a new transmembrane protein family, the CASPs, localized to the membrane domain underlying the CS, which we accordingly named the Casparian Strip membrane Domain (CSD). Our molecular analysis indicates that these proteins drive CS establishment. To identify more molecular factors of CS establishment, I performed a forward genetic screen. This screen led to the identification of 11 endodermis permissive mutants, which we named schengen (sgn) mutants. The causative mutations have been mapped to 5 independent loci: SGN1 to SGN5. SGN1 and SGN3 encode Receptor Like Kinases involved in the correct establishment of the CSD. A lack of those kinases leads to an incomplete CSD, which gives rise to interrupted CS barriers. Interestingly, SGN1 seems to also regulate CSD positioning to the middle of endodermal transversal walls. SGN4 encodes an NADPH oxidase involved in lignin polymerization essential for CS formation. The sgn5 mutant induces extra divisions of cortical cells strongly affecting the cell identity, but also leading to incorrect differentiation. A thorough characterization of the sgn2 mutant will follow elsewhere, yet preliminary results indicate that SGN2 encodes an Acyl-CoA N-acyltransferase. . In summary, with my work I have contributed a first set of molecular players of Casparian strip formation and initiated their characterization. Eventually, this might lead to an understanding of the molecular mechanisms of CS establishment in A.thaliana . This in turn will hopefully help to better understand nutrient uptake in higher plants and their response to environmental stresses. - Au sein des plantes vasculaires, l'endoderme représente un tissu protecteur mettant en place une barrière imperméable, empêchant n'importe quel élément de rejoindre les tissus conducteurs par simple diffusion. Cette barrière, appelée « Cadre de Caspary », correspond à une lignification de la paroi de l'endoderme et donne lieu à un cloisonnement de l'espace intercellulaire. Bien que cet élément de différenciation soit décrit en détail, sa mise en place reste incomprise. Cette étude indique la suite d'événements aboutissant à l'établissement du cadre de Caspary chez la plante modèle Arabidopsis thaliana. De plus, ce travail apporte de nouvelles connaissances expliquant comment ces cellules définissent des domaines membranaires importants pour le transport des nutriments. Nous décrivons une nouvelle famille de protéines membranaires, les CASPs (« CAparian Strip membrane domain Proteins »), localisées dans un domaine membranaire longeant le cadre de Caspary : le domaine de Caspary (CSD). L'analyse moléculaire des CASPs indique qu'elles dirigent la formation du cadre de Caspary. Par ailleurs, une approche génétique directe nous a permis d'identifier 11 mutants ayant un endoderme perméable. Nous avons nommé ces mutants Schengen, en référence à la zone de libre échange européenne. Les mutations impliquées dans ces mutants affectent 5 gènes désignés de SGN1 à SGN5. SGN1 et SGN3 produisent des protéines de type kinases (« Receptor-like Kinases », RLK) qui participent à la délimitation du CSD. L'absence de ces kinases aboutit à un domaine CSD incomplet, se traduisant par un cadre de Caspary discontinu. De plus, SGN1 semble réguler le positionnement du CSD au milieu de la paroi transversale de l'endoderme. SGN4 produit une enzyme de type NADPH oxydase impliquée dans la polymérisation du cadre de Caspary. Dans le mutant sgn5, on observe une division anormale des cellules du cortex créant ainsi une nouvelle couche cellulaire incapable d'achever sa différenciation en endoderme. Quant à la mutation sgn2, bien que nous pensons qu'elle affecte une Acyl-CoA N-acyltransferase, sa caractérisation ne sera réalisée que prochainement. Au final, ce travail procure de nouveaux éléments sur l'établissement du cadre de Caspary qui pourraient être importants afin de comprendre comment les plantes sélectionnent leurs nutriments et résistent à des conditions environnementales parfois hostiles. - De par leur immobilité, les plantes terrestres n'ont pas d'autre choix que de puiser leurs ressources dans leur environnement direct. La plante extrait du sol les nutriments qui lui sont nécessaires et les redistribue grâce à des tissus conducteurs. Afin de ne pas s'intoxiquer, il est donc essentiel de pouvoir sélectionner les éléments entrant dans la racine. Etonnement, ce n'est pas la surface des racines qui permet ce contrôle mais un tissu interne appelé endoderme. Ce dernier forme une barrière imperméable qui entoure chaque cellule et crée une jointure permettant de bloquer le passage des éléments entre les cellules. Cette structure, appelée « cadre de Caspary », oblige les éléments à entrer dans les cellules de l'endoderme et à être ainsi sélectionnés. Bien que cette structure soit décrite en détail, sa mise en place reste incomprise. Cette étude indique la suite d'événements qui aboutit à la formation du cadre de Caspary chez la plante modèle Arabidopsis thaliana. Ce travail apporte également de nouvelles connaissances expliquant comment ces cellules définissent, organisent et dirigent le transport des nutriments. Nous décrivons comment certains éléments de la cellule, les protéines CASPs (CAsparian Strip membrane domain Proteins), sont organisées un domaine particulier des membranes afin de créer une plateforme de construction longeant le cadre de Caspary : le domaine de Caspary (CSD). Afin de déterminer ce qu'il se passerait si une plante ne possédait pas de cadre de Caspary, nous avons réalisé une mutagénèse, ou approche génétique directe, et identifié 11 mutants (individu ayant un gène défectueux conduisant à la perte d'une fonction) ayant un endoderme perméable. Nous avons nommé ces mutants schengen, en référence à la zone de libre échange européenne. Les mutations impliquées dans ces mutants affectent 5 gènes désignés de SGN1 à SGN5. Les gènes SGN1 et SGN3 produisent des protéines de type kinases (« Receptor-like Kinases », RLK) servant à l'établissement de la plateforme de construction. L'absence de ces kinases aboutit à une base incomplète, se traduisant par un cadre de Caspary discontinu. Qui plus est, la kinase SGN1 semble réguler le positionnement de la plateforme au milieu de l'endoderme. Le gène SGN4 est par contre, impliqué dans la construction à proprement dite du cadre de Caspary. Dans le mutant sgn5, on observe une nouvelle couche de cellules ressemblant à de l'endoderme mais incapable de former correctement une barrière identique au cadre de Caspary. Quant au dernier mutant, sgn2, bien que cette étude fournisse des indices permettant de comprendre pourquoi le mutant sgn2 est défectueux, nous n'expliquerons ce cas que prochainement. En résumé, ce travail procure de nouvelles connaissances sur l'établissement du cadre de Caspary qui pourraient être importantes afin de comprendre comment les plantes sélectionnent leurs nutriments et résistent à des conditions environnementales parfois hostiles.

Current status and perspectives of cell therapy in Chagas disease

One century after its discovery, Chagas disease, caused by the protozoan, Trypanosoma cruzi, remains a major health problem in Latin America. Mortality and morbidity are mainly due to chronic processes that lead to dysfunction of the cardiac and digestive systems. About one third of the chronic chagasic individuals have or will develop the symptomatic forms of the disease, with cardiomyopathy being the most common chronic form. This is a progressively debilitating disease for which there are no currently available effective treatments other than heart transplantation. Like in other cardiac diseases, tissue engineering and cell therapy have been investigated in the past few years as a means of recovering the heart function lost as a consequence of chronic damage caused by the immune-mediated pathogenic mechanisms elicited in individuals with chronic chagasic cardiomyopathy. Here we review the studies of cell therapy in animal models and patients with chronic Chagas disease and the perspectives of the recovery of the heart function lost due to infection with T. cruzi.

Intracoronary injection of bone marrow-derived mononuclear cells early or late after acute myocardial infarction: effects on global left ventricular function.

BACKGROUND: Intracoronary administration of autologous bone marrow-derived mononuclear cells (BM-MNC) may improve remodeling of the left ventricle (LV) after acute myocardial infarction. The optimal time point of administration of BM-MNC is still uncertain and has rarely been addressed prospectively in randomized clinical trials. METHODS AND RESULTS: In a multicenter study, we randomized 200 patients with large, successfully reperfused ST-segment elevation myocardial infarction in a 1:1:1 pattern into an open-labeled control and 2 BM-MNC treatment groups. In the BM-MNC groups, cells were administered either early (ie, 5 to 7 days) or late (ie, 3 to 4 weeks) after acute myocardial infarction. Cardiac magnetic resonance imaging was performed at baseline and after 4 months. The primary end point was the change from baseline to 4 months in global LV ejection fraction between the 2 treatment groups and the control group. The absolute change in LV ejection fraction from baseline to 4 months was -0.4±8.8% (mean±SD; P=0.74 versus baseline) in the control group, 1.8±8.4% (P=0.12 versus baseline) in the early group, and 0.8±7.6% (P=0.45 versus baseline) in the late group. The treatment effect of BM-MNC as estimated by ANCOVA was 1.25 (95% confidence interval, -1.83 to 4.32; P=0.42) for the early therapy group and 0.55 (95% confidence interval, -2.61 to 3.71; P=0.73) for the late therapy group. CONCLUSIONS: Among patients with ST-segment elevation myocardial infarction and LV dysfunction after successful reperfusion, intracoronary infusion of BM-MNC at either 5 to 7 days or 3 to 4 weeks after acute myocardial infarction did not improve LV function at 4-month follow-up. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00355186.

Combined low initial DNA damage and high radiation-induced apoptosis confers clinical resistance to long-term toxicity in breast cancer patients treated with high-dose radiotherapy

BACKGROUND. Either higher levels of initial DNA damage or lower levels of radiation-induced apoptosis in peripheral blood lymphocytes have been associated to increased risk for develop late radiation-induced toxicity. It has been recently published that these two predictive tests are inversely related. The aim of the present study was to investigate the combined role of both tests in relation to clinical radiation-induced toxicity in a set of breast cancer patients treated with high dose hyperfractionated radical radiotherapy. METHODS. Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma treated with high-dose hyperfractioned radical radiotherapy. Acute and late cutaneous and subcutaneous toxicity was evaluated using the Radiation Therapy Oncology Group morbidity scoring schema. The mean follow-up of survivors (n = 13) was 197.23 months. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp). Radiation-induced apoptosis (RIA) at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide. RESULTS. Mean DSB/Gy/DNA unit obtained was 1.70 ± 0.83 (range 0.63-4.08; median, 1.46). Radiation-induced apoptosis increased with radiation dose (median 12.36, 17.79 and 24.83 for 1, 2, and 8 Gy respectively). We observed that those "expected resistant patients" (DSB values lower than 1.78 DSB/Gy per 200 Mbp and RIA values over 9.58, 14.40 or 24.83 for 1, 2 and 8 Gy respectively) were at low risk of suffer severe subcutaneous late toxicity (HR 0.223, 95%CI 0.073-0.678, P = 0.008; HR 0.206, 95%CI 0.063-0.677, P = 0.009; HR 0.239, 95%CI 0.062-0.929, P = 0.039, for RIA at 1, 2 and 8 Gy respectively) in multivariate analysis. CONCLUSIONS. A radiation-resistant profile is proposed, where those patients who presented lower levels of initial DNA damage and higher levels of radiation induced apoptosis were at low risk of suffer severe subcutaneous late toxicity after clinical treatment at high radiation doses in our series. However, due to the small sample size, other prospective studies with higher number of patients are needed to validate these results.

Interaction between ATM and PARP-1 in response to DNA damage and sensitization of ATM deficient cells through PARP inhibition

ATM and PARP-1 are two of the most important players in the cell's response to DNA damage. PARP-1 and ATM recognize and bound to both single and double strand DNA breaks in response to different triggers. Here we report that ATM and PARP-1 form a molecular complex in vivo in undamaged cells and this association increases after gamma-irradiation. ATM is also modified by PARP-1 during DNA damage. We have also evaluated the impact of PARP-1 absence or inhibition on ATM-kinase activity and have found that while PARP-1 deficient cells display a defective ATM-kinase activity and reduced gamma-H2AX foci formation in response to gamma-irradiation, PARP inhibition on itself is able to activate ATM-kinase. PARP inhibition induced gamma H2AX foci accumulation, in an ATM-dependent manner. Inhibition of PARP also induces DNA double strand breaks which were dependent on the presence of ATM. As consequence ATM deficient cells display an increased sensitivity to PARP inhibition. In summary our results show that while PARP-1 is needed in the response of ATM to gamma irradiation, the inhibition of PARP induces DNA double strand breaks (which are resolved in and ATM-dependent pathway) and activates ATM kinase.

Combinatorial effects of splice variants modulate function of Aiolos

The transcription factor Aiolos (also known as IKZF3), a member of the Ikaros family of zinc-finger proteins, plays an important role in the control of B lymphocyte differentiation and proliferation. Previously, multiple isoforms of Ikaros family members arising from differential splicing have been described and we now report a number of novel isoforms of Aiolos. It has been demonstrated that full-length Ikaros family isoforms localize to heterochromatin and that they can associate with complexes containing histone deacetylase (HDAC). In this study, for the first time we directly investigate the cellular localization of various Aiolos isoforms, their ability to heterodimerize with Ikaros and associate with HDAC-containing complexes, and the effects on histone modification and binding to putative targets. Our work demonstrates that the cellular activities of Aiolos isoforms are dependent on combinations of various functional domains arising from the differential splicing of mRNA transcripts. These data support the general principle that the function of an individual protein is modulated through alternative splicing, and highlight a number of potential implications for Aiolos in normal and aberrant lymphocyte function.

Impact of severe epilepsy on development: Recovery potential after successful early epilepsy surgery.

Purpose: Epilepsy surgery in young children with focal lesions offers a unique opportunity to study the impact of severe seizures on cognitive development during a period of maximal brain plasticity, if immediate control can be obtained. We studied 11 children with early refractory epilepsy (median onset, 7.5 months) due to focal lesion who were rendered seizure-free after surgery performed before the age of 6 years. Methods: The children were followed prospectively for a median of 5 years with serial neuropsychological assessments correlated with electroencephalography (EEG) and surgery-related variables. Results: Short-term follow-up revealed rapid cognitive gains corresponding to cessation of intense and propagated epileptic activity [two with early catastrophic epilepsy; two with regression and continuous spike-waves during sleep (CSWS) or frontal seizures]; unchanged or slowed velocity of progress in six children (five with complex partial seizures and frontal or temporal cortical malformations). Longer-term follow-up showed stabilization of cognitive levels in the impaired range in most children and slow progress up to borderline level in two with initial gains. Discussion: Cessation of epileptic activity after early surgery can be followed by substantial cognitive gains, but not in all children. In the short term, lack of catch-up may be explained by loss of retained function in the removed epileptogenic area; in the longer term, by decreased intellectual potential of genetic origin, irreversible epileptic damage to neural networks supporting cognitive functions, or reorganization plasticity after early focal lesions. Cognitive recovery has to be considered as a "bonus," which can be predicted in some specific circumstances.

Lung function in idiopathic pulmonary fibrosis--extended analyses of the IFIGENIA trial.

BACKGROUND The randomized placebo-controlled IFIGENIA-trial demonstrated that therapy with high-dose N-acetylcysteine (NAC) given for one year, added to prednisone and azathioprine, significantly ameliorates (i.e. slows down) disease progression in terms of vital capacity (VC) (+9%) and diffusing capacity (DLco) (+24%) in idiopathic pulmonary fibrosis (IPF). To better understand the clinical implications of these findings we performed additional, explorative analyses of the IFGENIA data set. METHODS We analysed effects of NAC on VC, DLco, a composite physiologic index (CPI), and mortality in the 155 study-patients. RESULTS In trial completers the functional indices did not change significantly with NAC, whereas most indices deteriorated with placebo; in non-completers the majority of indices worsened but decline was generally less pronounced in most indices with NAC than with placebo. Most categorical analyses of VC, DLco and CPI also showed favourable changes with NAC. The effects of NAC on VC, DLco and CPI were significantly better if the baseline CPI was 50 points or lower. CONCLUSION This descriptive analysis confirms and extends the favourable effects of NAC on lung function in IPF and emphasizes the usefulness of VC, DLco, and the CPI for the evaluation of a therapeutic effect. Most importantly, less progressed disease as indicated by a CPI of 50 points or lower at baseline was more responsive to therapy in this study.

MicroRNA Profile of Circulating CD4-positive Regulatory T Cells in Human Adults and Impact of Differentially Expressed MicroRNAs on Expression of Two Genes Essential to Their Function.

Regulatory T cells (Tregs) are characterized by a high expression of IL-2 receptor α chain (CD25) and of forkhead box P3 (FOXP3), the latter being essential for their development and function. Another major player in the regulatory function is the cytotoxic T-lymphocyte associated molecule-4 (CTLA-4) that inhibits cytotoxic responses. However, the regulation of CTLA-4 expression remains less well explored. We therefore studied the microRNA signature of circulating CD4(+) Tregs isolated from adult healthy donors and identified a signature composed of 15 differentially expressed microRNAs. Among those, miR-24, miR-145, and miR-210 were down-regulated in Tregs compared with controls and were found to have potential target sites in the 3'-UTR of FOXP3 and CTLA-4; miR-24 and miR-210 negatively regulated FOXP3 expression by directly binding to their two target sites in its 3'-UTR. On the other hand, miR-95, which is highly expressed in adult peripheral blood Tregs, positively regulated FOXP3 expression via an indirect mechanism yet to be identified. Finally, we showed that miR-145 negatively regulated CTLA-4 expression in human CD4(+) adult peripheral blood Tregs by binding to its target site in CTLA-4 transcript 3'-UTR. To our knowledge, this is the first identification of a human adult peripheral blood CD4(+) Treg microRNA signature. Moreover, unveiling one mechanism regulating CTLA-4 expression is novel and may lead to a better understanding of the regulation of this crucial gene.

Regional and hemispheric determinants of language laterality: Implications for preoperative fMRI.

Language is typically a function of the left hemisphere but the right hemisphere is also essential in some healthy individuals and patients. This inter-subject variability necessitates the localization of language function, at the individual level, prior to neurosurgical intervention. Such assessments are typically made by comparing left and right hemisphere language function to determine "language lateralization" using clinical tests or fMRI. Here, we show that language function needs to be assessed at the region and hemisphere specific level, because laterality measures can be misleading. Using fMRI data from 82 healthy participants, we investigated the degree to which activation for a semantic word matching task was lateralized in 50 different brain regions and across the entire cortex. This revealed two novel findings. First, the degree to which language is lateralized across brain regions and between subjects was primarily driven by differences in right hemisphere activation rather than differences in left hemisphere activation. Second, we found that healthy subjects who have relatively high left lateralization in the angular gyrus also have relatively low left lateralization in the ventral precentral gyrus. These findings illustrate spatial heterogeneity in language lateralization that is lost when global laterality measures are considered. It is likely that the complex spatial variability we observed in healthy controls is more exaggerated in patients with brain damage. We therefore highlight the importance of investigating within hemisphere regional variations in fMRI activation, prior to neuro-surgical intervention, to determine how each hemisphere and each region contributes to language processing. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.

ALDH1A3 loss of function causes bilateral anophthalmia/microphthalmia and hypoplasia of the optic nerve and optic chiasm.

The major active retinoid, all-trans retinoic acid, has long been recognized as critical for the development of several organs, including the eye. Mutations in STRA6, the gene encoding the cellular receptor for vitamin A, in patients with Matthew-Wood syndrome and anophthalmia/microphthalmia (A/M), have previously demonstrated the importance of retinol metabolism in human eye disease. We used homozygosity mapping combined with next-generation sequencing to interrogate patients with anophthalmia and microphthalmia for new causative genes. We used whole-exome and whole-genome sequencing to study a family with two affected brothers with bilateral A/M and a simplex case with bilateral anophthalmia and hypoplasia of the optic nerve and optic chiasm. Analysis of novel sequence variants revealed homozygosity for two nonsense mutations in ALDH1A3, c.568A>G, predicting p.Lys190*, in the familial cases, and c.1165A>T, predicting p.Lys389*, in the simplex case. Both mutations predict nonsense-mediated decay and complete loss of function. We performed antisense morpholino (MO) studies in Danio rerio to characterize the developmental effects of loss of Aldh1a3 function. MO-injected larvae showed a significant reduction in eye size, and aberrant axonal projections to the tectum were noted. We conclude that ALDH1A3 loss of function causes anophthalmia and aberrant eye development in humans and in animal model systems.