Plasma ceramide, a real-time predictive marker of pulmonary and hepatic metastases response to stereotactic body radiation therapy combined with irinotecan

AbstractBackground and purposesEarly biomarkers of tumour response are needed to discriminate between responders and non-responders to radiotherapy. We evaluated the ability of ceramide, a bioactive sphingolipid, to predict tumour sensitivity in patients treated by hypofractionated stereotactic body radiation therapy (SBRT) combined with irinotecan chemotherapy.Materials and methodsPlasma levels of total ceramide and of its subspecies were measured before and during treatment in 35 patients with liver and lung oligometastases of colorectal cancer included in a phase II trial. Cer levels were quantified by LC–ESI-MS/MS and compared to tumour volume response evaluated one year later by CT-scan.ResultsPretreatment plasma ceramide levels were not indicative of tumour response. Nevertheless, the levels of total ceramide and of its 4 main subspecies were significantly higher at days 3 and 10 of treatment in objective responders than in non-responders. According to Kaplan–Meier curves, almost complete tumour control was achieved at 1year in patients with increased total ceramide levels whereas 50% of patients with decreased levels experienced an increase in tumour volume.ConclusionsTotal plasma ceramide is a promising biomarker of tumour response to SBRT combined with irinotecan that should enable to segregate patients with high risk of tumour escape

Radiothérapie et athérome

L’optimisation constante des traitements du cancer par radiothérapie pose le problème du devenir à long terme des patients traités et guéris par les rayonnements ionisants, et de la survenue éventuelle de seconds cancers ou de complications non cancéreuses. Parmi ces dernières, les pathologies cardiovasculaires sont prédominantes et peuvent concerner jusqu’à 40 % des patients selon la localisation de l’irradiation. Les dernières études épidémiologiques montrent que ce problème est sous-estimé et n’a pas fait l’objet de réelles études prospectives. La prise en charge thérapeutique de ces patients à risque vasculaire, voire à très haut risque s’ils présentent des facteurs de risque cardiovasculaires traditionnels préexistants, reste à déterminer. Les mécanismes physiopathologiques de l’athérome radio-induit ne sont pas encore clarifiés. La surveillance vasculaire prolongée des patients à distance de leur traitement par radiothérapie doit désormais être intégrée dans les schémas de soins, d’autant plus que la mise en place d’un plateau technique de radiothérapie de plus en plus sophistiqué ne résoudra pas forcément le problème du risque cardiovasculaire après traitement

RhoA GTPase regulates radiation-induced alterations in endothelial cell adhesion and migration

International audienceEndothelial cells of the microvasculature are major target of ionizing radiation, responsible of the radiationinduced vascular early dysfunctions. Molecular signaling pathways involved in endothelial responses to ionizing radiation, despite being increasingly investigated, still need precise characterization. Small GTPase RhoA and its effector ROCK are crucial signaling molecules involved in many endothelial cellular functions. Recent studies identified implication of RhoA/ROCK in radiation-induced increase in endothelial permeability but other endothelial functions altered by radiation might also require RhoA proteins. Human microvascular endothelial cells HMEC-1, either treated with Y-27632 (inhibitor of ROCK) or invalidated for RhoA by RNA interference were exposed to 15 Gy. We showed a rapid radiation-induced activation of RhoA, leading to a deep reorganisation of actin cytoskeleton with rapid formation of stress fibers. Endothelial early apoptosis induced by ionizing radiation was not affected by Y-27632 pre-treatment or RhoA depletion. Endothelial adhesion to fibronectin and formation of focal adhesions increased in response to radiation in a RhoA/ROCK-dependent manner. Consistent with its pro-adhesive role, ionizing radiation also decreased endothelial cells migration and RhoA was required for this inhibition. These results highlight the role of RhoA GTPase in ionizing radiation-induced deregulation of essential endothelial functions linked to actin cytoskeleton

Editorial: innovative radiopharmaceuticals in oncology and Neurology

International audienceEditorial on the Research Topic Innovative Radiopharmaceuticals in Oncology and Neurology Personalized medicine is presented as the future of patient care. Nuclear Medicine will play a major role in the selection of patients for targeted therapies and in early therapy assessment with the investigation of phenotypes and functions using sensitive and specific SPECT and PET imaging techniques and theranostic approaches. Nuclear Medicine is already a key in the development of new therapies and targeted radionuclide therapy provides efficacious treatment modalities against cancer. An incredible amount of innovation is related to the use of a variety of radionuclides, new or improved multimodality imaging devices, and numbers of recently marketed radiopharmaceuticals in all medical domains and particularly cardiology, neurology, and oncology. In this context, a network of laboratories and Nuclear Medicine departments, the IRON Laboratory of Excellence (Labex), has been set as part of the French " Investissements d' Avenir " program to help translating innovative radiopharmaceuticals into clinical testing by a multidisciplinary approach from the production of radionuclides using cyclotrons, to basic studies of targets and ligands, clinical trials, and assessment of the societal impacts of innovation in medicine in neurology and oncology. To foster communication between scientists, inside the Labex and with the international community, a series of highly specialized international " Nuclear Technologies for Health Symposia " has been organized annually, with the most recent edition, the third, held in Nantes, France, on March 10–11, 2015. Plenary lectures given by distinguished speakers (Hank Kung, Philadelphia, PA, USA, Tom Bäck, Gothenburg, Sweden, Otto Boerman, Nijmegen, The Netherlands, Franck Bruchertseifer, Karlsruhe, Germany, and Claire Tabouret-Viaud, Geneva, Switzerland) addressed the state of the arts and new developments in the use of radioactivity and radiopharmaceuticals for multimodality imaging and therapy. The latest achievements in clinical nuclear medicine, science, and technology were discussed during interactive oral and poster sessions. Selected talks were organized in four sessions: innovative tracers in neurology: from bench to bedside, multimodality imaging, theranostic in nuclear medicine, and targeted radionuclide therapy. After the meeting, 12 papers were published in the Nuclear Medicine topic open by Frontiers in Medicine. These papers are representative of current research and development in Nuclear Medicine

Ionizing radiation induces long-term senescence in endothelial cells through mitochondrial respiratory complex II dysfunction and superoxide generation

International audienceIonizing radiation causes oxidative stress, leading to acute and late cellular responses. We previously demonstrated that irradiation of non-proliferating endothelial cells, as observed in normal tissues, induces early apoptosis, which can be inhibited by pretreatment with Sphingosine-1-Phosphate. We now propose to better characterize the long-term radiation response of endothelial cells by studying the molecular pathways associated with senescence and its link with acute apoptosis. First, senescence was validated in irradiated quiescent microvascular HMVEC-L in a dose- and time-dependent manner by SA β-galactosidase staining, p16Ink4a and p21Waf1 expression, pro-inflammatory IL-8 secretion and DNA damage responseactivation. This premature aging was induced independently of Sphingosine 1-Phosphate treatment, supporting its non-connection with acute IR-induced apoptosis. Then, senescence under these conditions showed persistent activation of p53 pathway and mitochondrial dysfunctions, characterized by O2●- generation, inhibition of respiratory complex II activity andover-expression of SOD2 and GPX1 detoxification enzymes. Senescence was significantly inhibited by treatment with pifithrin–α, a p53 inhibitor, or by MnTBAP, a superoxide dismutase mimetic, validating those molecular actors in IR-induced endothelial cell aging. However, MnTBAP, but not pifithrin–α, was able to limit superoxide generation and to rescue the respiratory complex II activity. Furthermore, MnTBAP was not modulating p53 up-regulation, suggesting that IR-induced senescence in quiescent endothelial cells is provided by at least 2 different pathways dependent of the mitochondrial oxidative stress response and the p53 activation. Further characterization of the actors involved in the respiratory complex II dysfunction will open new pharmacological strategies to modulate late radiation toxicity

Anti-Gb3 monoclonal antibody inhibits angiogenesis and tumor development.

Inhibiting the growth of tumor vasculature represents one of the relevant strategies against tumor progression. Between all the different pro-angiogenic molecular targets, plasma membrane glycosphingolipids have been under-investigated. In this present study, we explore the anti-angiogenic therapeutic advantage of a tumor immunotherapy targeting the globotriaosylceramide Gb3. In this purpose, a monoclonal antibody against Gb3, named 3E2 was developed and characterized. We first demonstrate that Gb3 is over-expressed in proliferative endothelial cells relative to quiescent cells. Then, we demonstrate that 3E2 inhibits endothelial cell proliferation in vitro by slowing endothelial cell proliferation and by increasing mitosis duration. Antibody 3E2 is further effective in inhibiting ex vivo angiogenesis in aorta ring assays. Moreover, 3E2 treatment inhibits NXS2 neuroblastoma development and liver metastases spreading in A/J mice. Immunohistology examination of the NXS2 metastases shows that only endothelial cells, but not cancer cells express Gb3. Finally, 3E2 treatment diminishes tumor vessels density, proving a specific therapeutic action of our monoclonal antibody to tumor vasculature. Our study demonstrates that Gb3 is a viable alternative target for immunotherapy and angiogenesis inhibition

Therapeutic Efficacy of Alpha-RIT Using a (213)Bi-Anti-hCD138 Antibody in a Mouse Model of Ovarian Peritoneal Carcinomatosis

International audiencePURPOSE: Ovarian peritoneal carcinomatosis is a pathology for which effective cures are currently lacking. New research protocols seek to eradicate residual micrometastases following cytoreductive surgery by using hyperthermic intraperitoneal chemotherapy (HIPEC) or radioimmunotherapy (RIT). This study aims to first develop alpha-RIT using an anti-CD138 mAb radiolabeled with an alpha-emitter, bismuth-213 ((213)Bi-B-B4) and HIPEC in a nude mouse model and second to compare and combine these techniques.MATERIAL AND METHODS: A murine model of postoperative ovarian peritoneal carcinomatosis was established. A pilot group of six mice received an intraperitoneal injection of luciferase-tagged SHIN-3 cells and bioluminescence was measured every day. Cytoreductive surgery was performed at day 14 (n = 4) and 29 (n = 2). Because the residual bioluminescence signal measured after surgery was equivalent to that obtained 3 days after the graft, HIPEC or alpha-RIT treatments were applied 3 days after the graft. Ten mice were treated by HIPEC with cisplatine (37.5 mg/mL), 11 with 7.4 MBq of (213)Bi-B-B4, seven with 11.1 MBq of (213)Bi-B-B4, and 10 mice were treated with the combined therapy (HIPEC + 7.4 MBq of (213)Bi-B-B4). Eleven mice received no treatment. Bioluminescence imaging and survival were assessed.RESULTS: Alpha-RIT 7.4 MBq and 11.1 MBq significantly improved survival (p = 0.0303 and p = 0.0070, respectively), whereas HIPEC and HIPEC + alpha-RIT treatments did not significantly ameliorate survival as compared to the control group. CONCLUSION: Survival was significantly increased by alpha-RIT treatment in mice with peritoneal carcinomatosis of ovarian origin; however, HIPEC alone or in combination with alpha-RIT had no significant effect

Plasma membrane reorganization links acid sphingomyelinase/ceramide to p38 MAPK pathways in endothelial cells apoptosis

International audienceThe p38 MAPK signaling pathway is essential in the cellular response to stress stimuli, in particular in the endothelial cells that are major target of external stress. The importance of the bioactive sphingolipid ceramide generated by acid sphingomyelinase is also firmly established in stress-induced endothelial apoptotic cell death. Despite a suggested link between the p38 MAPK and ceramide pathways, the exact molecular events of this connection remain elusive. In the present study, by using two different activators of p38 MAPK, namely anisomycin and ionizing radiation, we depicted how ceramide generated by acid sphingomyelinase was involved in p38 MAPK-dependent apoptosis of endothelial cells. We first proved that both anisomycin and ionizing radiation conducted to apoptosis through activation of p38 MAPK in human microvascular endothelial cells HMEC-1. We then found that both treatments induced activation of acid sphin-gomyelinase and the generation of ceramide. This step was required for p38 MAPK activation and apoptosis. We finally showed that irradiation, as well as treatment with exogenous C 16-ceramide or bacterial sphingomyelinase, induced in en-dothelial cells a deep reorganization of the plasma membrane with formation of large lipid platforms at the cell surface, leading to p38 MAPK activation and apoptosis in endothelial cells. Altogether, our results proved that the plasma membrane reorganization leading to ceramide production is essential for stress-induced activation of p38 MAPK and apoptosis in endothelial cells and established the link between the acid sphingomyelinase/ceramide and p38 MAPK pathways