ESTRO 36 Abstract Book

S539 ESTRO 36 2017 _______________________________________________________________________________________________

Y.M. Liu 1 , Y.J. Chen 2 , Y.K. Liu 3 , T.H. Tsai 4 1 Taipei Veteran General Hospital, Div. of Radiation Oncology- Dept. of Oncology, Taipei, Taiwan 2 MacKay Memorial Hospital, Department of Radiation Oncology, New Taipei City, Taiwan 3 Chang Gung University, Department of Chemical and Material Engineering, Taoyuan City, Taiwan 4 National Yang Ming University, Institute of Traditional Medicine, Taipei, Taiwan Purpose or Objective This study investigated the adjunctive effects of Antrodia cinnamomea mycelial fermentation broth ( AC -MFB), a Taiwanese medicinal fungus, in enhancing the radiosensitivity of esophageal cancer cells. in vitro and in vivo. Material and Methods Materials: Antrodia cinnamomea mycelial fermentation broth, Human CE81T/VGH squamous and BE3 adenocarcinoma esophageal cancer cells, BALB/c mice. Method: MTT assay, colony formation assay, DNA histogram study, γ-H2AX immunofluorescence assay, Western blotting assay, BALB/c mice animal model study. Results A colony formation assay showed that pretreatment with AC -MFB decreased the survival of irradiated esophageal cancer cells, with a maximum sensitizer enhancement ratio of 1.91 and 37% survival. A DNA histogram study showed that AC -MFB pretreatment enhanced cell cycle arrest at the G2/M phase, the most radiosensitive phase. An immunofluorescence assay and a Western blotting assay showed that AC -MFB delayed the abrogation of γ- H2AX, upregulated p21 expression, and attenuated the radiation-induced phosphorylation of ataxia telangiectasia-mutated kinase and checkpoint kinase 2. An in vivo validation study showed that AC -MFB treatment tended to have a synergistic effect with radiation on the tumor growth delay of CE81T/VGH cells in BALB/c mice. Conclusion These data suggest that this edible fungus product could enhance the effect of radiotherapy against esophageal cancer. PO-0984 Checkpoint HLA-G or its ligands ILT2/ILT4 changes radiosensitivity of renal carcinoma cell lines C. Hennequin 1 , M. Daouya 1 , D. Tronik-Le Roux 1 , J. LeMaoult 1 , N. Rouas-Freiss 1 , F. Desgrandchamps 1 , E. Carosella 1 1 Hôpital Saint-Louis, Research in Immuno-hematology, Paris, France Purpose or Objective HLA-G is an immune checkpoint physiologically implicated in maternal-foetal tolerance. It is also neoexpressed in many cancers and particularly in more than 50% of renal cancers. Stereotactic radiotherapy efficiency is at least in part mediated by the immune system, and could be modulated by the presence of immune checkpoints; for example the use of antibodies directed against PD1/PDL1 increased radiotherapy efficiency. We investigated the impact of expression of HLA-G or its ligands (ILT2/ILT4) on radiotherapy efficiency at the cellular level on renal carcinoma cell lines (RCCL). Material and Methods The effect of ionizing radiations (IR: 8 Gy) on the expression of HLA-G, ILT2 and ILT4 was evaluated on RCCL expressing or not HLA-G, ILT2 or ILT4. The impact of HLA- G, ILT or ILT4 expression on radiosensitivity was evaluated by clonogenic assays on transduced RCCL or controls. In order to explain the results obtained, the following mechanisms were investigated by cytofluorimetry: 1/ quantification of double-strand breaks (H2AX) 2/ apoptosis (Annexin V and propidium iodin PI) 3/ Cell cycle modifications (PI) Results

Our results showed that IR on RCCL not expressing HLA-G, ILT2 or ILT4 did not induce these molecules. However, in constitutively expressing HLA-G or ILT4 RCCL, IR decreased significantly HLA-G and ILT4 expression. Furthermore, we found that HLA-G, ILT2 and ILT4 transduction increased radioresistance. This effect was partially aborted by the use of antibodies directed against these molecules. Mechanisms of radio resistance are under investigations and will be presented at the meeting. Conclusion Ionizing radiation decreases the expression of HLA-G or its receptors in RCCL constitutively expressing these molecules. HLA-G and its ligands increase radioresistance. This finding could have some clinical implications for stereotactic radiotherapy of renal cancer or its metastasis. PO-0985 Tumor metabolic changes after neoadjuvant radiotherapy: consequences for surgery-related metastases N. Leroi 1 , F. Lallemand 2 , J. Leenders 3 , S. Blacher 4 , P. De Tullio 3 , P. Coucke 5 , A. Noel 4 , P. Martinive 1 1 C.H.U. Liège - Université de Liège, Radiotherapy Dept- Laboratoire de Biologie des Tumeurs et du Développement, Liège, Belgium 2 C.H.U. Liège - Université de Liège, Radiotherapy Dept- Research center of Cyclotron, Liège, Belgium 3 Université de Liège, CIRM- Chimie Pharmaceutique, Liège, Belgium 4 Université de Liège, Laboratoire de Biologie des Tumeurs et du Développement, Liège, Belgium 5 C.H.U. Liège - Université de Liège, Radiotherapy Dept., Liège, Belgium Purpose or Objective Neoadjuvant radiotherapy (NeoRT) aims at improving tumor local control and patient overall survival. In the case of locally advanced rectal cancer, NeoRT increases significantly local control compared to surgery alone, but patient overall survival is not improved. Currently, predicting tumor response and recurrences represent a major challenge for personalized medicine. Previously, we developed a pre-clinical model of NeoRT and showed that the timing of surgery and NeoRT schedules both influenced metastasis burden (Leroi et al., Oncotarget, 2015). Based on this model, we study the impact of RT schedule on the primary tumor metabolome at the time of surgery to predict local recurrence and metastatic profile. Material and Methods We locally irradiated primary tumors (MDA-MB231 cells and 4T1 cells), subcutaneously implanted to SCID and BalbC mice, with two NeoRT schedules (5x2Gy and 2x5Gy). We surgically removed tumors 4 or 11 days after the end of RT and kept the mice alive for the metastatic growth. Non-irradiated control tumors were also surgically collected at the same time. For metabolomic study, tumor samples were homogenized in deuterated phosphate buffer and supplemented with maleic acid and TMSP before Nuclear Magnetic Resonance (NMR) analyses. Data were analyzed with powerful statistical tool (supervised and multivariate analyses). Results Irradiated 4T1 and MDA-MB231 tumors displayed different metabolic profile than non-irradiated tumors, especially 4 days after the end of RT for 4T1 tumors and 11 days after NeoRT for MDA-MB231 tumors. Moreover, we observed a decrease in some metabolite levels (i.e. glutamate, taurine, glycine, myoinositol) in tumors following both NeoRT schedules. We also noticed an increase in general lipid signals in irradiated MDA-MB231 tumors. This was not related to adipocyte infiltration, as we observed, by immunostaining, decreased infiltration of perilipin and FABP4+ cells in these tumors following NeoRT. Preliminary results with OPLS-DA analyses showed discrimination of primary tumor metabolome according to the propensity to