An international phase II trial and immune profiling of SBRT and atezolizumab in advanced pretreated colorectal cancer

BACKGROUND

Immuno-radiotherapy may improve outcomes for patients with advanced solid tumors, although optimized combination modalities remain unclear. Here, we report the colorectal (CRC) cohort analysis from the SABR-PDL1 trial that evaluated the PD-L1 inhibitor atezolizumab in combination with stereotactic body radiation therapy (SBRT) in advanced cancer patients.

METHODS

Eligible patients received atezolizumab 1200 mg every 3 weeks until progression or unmanageable toxicity, together with ablative SBRT delivered concurrently with the 2nd cycle (recommended dose of 45 Gy in 3 fractions, adapted upon normal tissue tolerance constraint). SBRT was delivered to at least one tumor site, with at least one additional measurable lesion being kept from the radiation field. The primary efficacy endpoint was one-year progression-free survival (PFS) rate from the start of atezolizumab. Sequential tumor biopsies were collected for deep multi-feature immune profiling.

RESULTS

Sixty pretreated (median of 2 prior lines) advanced CRC patients (38 men [63%]; median age, 59 years [range, 20-81 years]; 77% with liver metastases) were enrolled in five centers (France: n = 4, Spain: n = 1) from 11/2016 to 04/2019. All but one (98%) received atezolizumab and 54/60 (90%) received SBRT. The most frequently irradiated site was lung (n = 30/54; 56.3%). Treatment-related G3 (no G4-5) toxicity was observed in 3 (5%) patients. Median OS and PFS were respectively 8.4 [95%CI:5.9-11.6] and 1.4 months [95%CI:1.2-2.6], including five (9%) patients with PFS > 1 year (median time to progression: 19.2 months, including 2/5 MMR-proficient). Best overall responses consisted of stable disease (n = 38; 64%), partial (n = 3; 5%) and complete response (n = 1; 2%). Immune-centric multiplex IHC and RNAseq showed that SBRT redirected immune cells towards tumor lesions, even in the case of radio-induced lymphopenia. Baseline tumor PD-L1 and IRF1 nuclear expression (both in CD3 + T cells and in CD68 + cells) were higher in responding patients. Upregulation of genes that encode for proteins known to increase T and B cell trafficking to tumors (CCL19, CXCL9), migration (MACF1) and tumor cell killing (GZMB) correlated with responses.

CONCLUSIONS

This study provides new data on the feasibility, efficacy, and immune context of tumors that may help identifying advanced CRC patients most likely to respond to immuno-radiotherapy.

TRIAL REGISTRATION

EudraCT N°: 2015-005464-42; Clinicaltrial.gov number: NCT02992912.

Clinico-Genomic Characterization of Patients with Metastatic Urothelial Carcinoma in Real-World Practice Identifies a Novel Bladder Immune Performance Index (BIPI)

PURPOSE

This retrospective analysis of the largest available clinico-genomic database used de-identified patient-level electronic health record-derived real-world data (RWD) combined with FoundationOne® comprehensive genomic profiling (CGP) to characterize patients with metastatic urothelial carcinoma (mUC) treated in the real-world setting, detect potential biomarkers, and develop a bladder immune performance index (BIPI).

EXPERIMENTAL DESIGN

Patients with mUC who started front-line single-agent immune checkpoint inhibitors (ICIs) and an unmatched group treated with front-line platinum-based chemotherapy between January 1, 2011 and September 30, 2019 were selected. Clinical and genomic data were correlated with overall survival (OS). A novel BIPI predicting outcome with ICIs was developed using machine learning methods and validated using data from a phase II trial (NCT02951767).

RESULTS

In ICI-treated patients (n=118), high tumor mutational burden (≥10 mutations/megabase) was associated with improved OS (HR 0.58 [95% CI, 0.35-0.95]; P=0.03). In chemotherapy-treated patients (n=268), those with high APOBEC mutational signature had worse OS (HR 1.43 [95% CI, 1.06-1.94]; P=0.02). Neither FGFR3 mutations nor DNA damage-repair pathway alterations were associated with OS. A novel BIPI combining clinical and genomic variables (non-metastatic at initial diagnosis, normal or above normal albumin level at baseline, prior surgery for organ-confined disease, high TMB) identified ICI-treated patients with longest OS and was validated in an independent dataset.

CONCLUSIONS

Contemporary RWD including FoundationOne® CGP can be used to characterize outcomes in real-world patients according to biomarkers beyond PD-L1. A validated, novel clinico-genomic BIPI demonstrated satisfactory prognostic performance for OS in patients with mUC receiving front-line ICI therapy.

Real-world progression-free survival (rwPFS) and time to next line of therapy (TTNT) as intermediate endpoints for survival in metastatic breast cancer: A real-world experience

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Background: Real-world progression-free survival (rwPFS) and time to next line of therapy (TTNT) are two endpoints of clinical interest in patients with metastatic breast cancer (MBC). Their validation as intermediate endpoints for overall survival (OS), in a real-world setting, remains not fully established. Methods: We conducted a retrospective cohort study using the nationwide US Electronic Health Record-derived de-identified Flatiron Health database. The study population included pts diagnosed with MBC from Jan 1, 2011 to Feb 30, 2021. rwPFS was defined as the time from start of first-line systemic therapy for MBC to disease progression or death. TTNT was defined as the time from start of first-line systemic therapy until start of next line of therapy. The nonparametric Kendall tau correlation between each surrogate endpoint (rwPFS and TTNT) and OS was evaluated using the Hougaard copula model in the Weibull margin distribution. Kendall’s tau (τ) with its 95%CI was calculated across the entire dataset, and within each disease subgroup defined by receptor (ER and/or PR status defined as hormone receptor [HR], and HER2) status. This work was conducted on behalf of the imCORE network and the Dana-Farber Cancer Institute. Results: Overall, 9,770 patients with MBC were included. Median age was 63 years (IQR: 54-72 years). HR+/HER2- disease represented the most frequent MBC subtype (n=6,287; 64.4%), followed by HER2+ (n=2,096; 21.5%) and triple negative (n=1,387; 14.2%) disease. Median f/u was 41.5 months (95%CI: 40.4 to 42.8). Median OS in the overall population was 32.4 months (95%CI: 31.2 to 33.3). Median rwPFS was 11.5 months (95%CI: 11.1 to 11.9), and median TTNT was 11.1 months (95%CI: 10.7 to 11.5). Across the entire population, the correlation of rwPFS with OS was 0.54 (95%CI: 0.53-0.56), while the correlation of TTNT with OS was 0.47 (95%CI: 0.46-0.48) (Table). Conclusions: rwPFS and TTNT may represent meaningful intermediate endpoints for OS in patients with MBC overall, and within the different disease subgroups. [Table: see text]

Epithelial-to-mesenchymal transition promotes immune escape by inducing CD70 in non-small cell lung cancer

INTRODUCTION

Epithelial-to-mesenchymal transition (EMT) is associated with tumor aggressiveness, drug resistance, and poor survival in non-small cell lung cancer (NSCLC) and other cancers. The identification of immune-checkpoint ligands (ICPLs) associated with NSCLCs that display a mesenchymal phenotype (mNSCLC) could help to define subgroups of patients who may benefit from treatment strategies using immunotherapy.

METHODS

We evaluated ICPL expression in silico in 130 NSCLC cell lines. In vitro, CRISPR/Cas9-mediated knockdown and lentiviral expression were used to assess the impact of ZEB1 expression on CD70. Gene expression profiles of lung cancer samples from the TCGA (n = 1018) and a dataset from MD Anderson Cancer Center (n = 275) were analyzed. Independent validation was performed by immunohistochemistry and targeted-RNA sequencing in 154 NSCLC whole sections, including a large cohort of pulmonary sarcomatoid carcinomas (SC, n = 55).

RESULTS

We uncover that the expression of CD70, a regulatory ligand from the tumor necrosis factor ligand family, is enriched in mNSCLC in vitro models. Mechanistically, the EMT-inducer ZEB1 impacted CD70 expression and fostered increased activity of the CD70 promoter. CD70 overexpression was also evidenced in mNSCLC patient tumor samples and was particularly enriched in SC, a lung cancer subtype associated with poor prognosis. In these tumors, CD70 expression was associated with decreased CD3⁺ and CD8⁺ T-cell infiltration and increased T-cell exhaustion markers.

CONCLUSION

Our results provide evidence on the pivotal roles of CD70 and ZEB1 in immune escape in mNSCLC, suggesting that EMT might promote cancer progression and metastasis by not only increasing cancer cell plasticity but also reprogramming the immune response in the local tumor microenvironment.

Frequency and Genomic Aspects of Intrinsic Resistance to Vismodegib in Locally Advanced Basal Cell Carcinoma

PURPOSE

Vismodegib is approved for the treatment of locally advanced basal cell carcinoma (laBCC), but some cases demonstrate intrinsic resistance (IR) to the drug. We sought to assess the frequency of IR to vismodegib in laBCC and its underlying genomic mechanisms.

EXPERIMENTAL DESIGN

Response to vismodegib was evaluated in a cohort of 148 laBCC patients. Comprehensive genomic and transcriptomic profiling was performed in a subset of five intrinsically resistant BCC (IR-BCC).

RESULTS

We identified that IR-BCC represents 6.1% of laBCC in the studied cohort. Prior treatment with chemotherapy was associated with IR. Genetic events that were previously associated with acquired resistance (AR) in BCC or medulloblastoma were observed in three out of five IR-BCC. However, IR-BCCs were distinct by highly rearranged polyploid genomes. Functional analyses identified hyperactivation of the HIPPO-YAP and WNT pathways at RNA and protein levels in IR-BCC. In vitro assay on the BCC cell line further confirmed that YAP1 overexpression increases the cell proliferation rate.

CONCLUSIONS

IR to vismodegib is a rare event in laBCC. IR-BCCs frequently harbor resistance mutations in the Hh pathway, but also are characterized by hyperactivation of the HIPPO-YAP and WNT pathways.

Clinico-genomic characterization of patients with metastatic urothelial carcinoma in real-world practice and development of a novel bladder immune prognostic index (BIPI)

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Background: Real-world data (RWD) linking clinical outcomes with comprehensive genomic profiling (CGP) may enable identification of biomarkers to guide treatment selection and stratification in future trials. The primary objective was to characterize patients with metastatic urothelial carcinoma (mUC) included in a clinic-genomic database (CGDB), comprised of the electronic health record-derived Flatiron Health database with linked FoundationOne CGP results. As secondary objective, a novel Bladder Immune Prognostic Index (BIPI) was developed. Methods: A retrospective exploratory analysis was performed of de-identified RWD, retrieved from the CGDB. Data from mUC patients starting first-line single-agent immune checkpoint inhibitors (ICIs) and an unmatched group treated with front-line platinum-based chemotherapy (CHT) between Jan 1, 2011, and Sept 30, 2019, were analyzed and correlated with overall survival (OS). Known driver alterations, tumor mutational burden (TMB), and PD-L1 expression were described. A BIPI predicting outcome with ICIs was developed using a Cox-LASSO model and validated externally in a phase II trial (NCT02951767). Results: Of the 1021 patients with mUC identified in CGDB, 118 ICI-treated and 268 CHT-treated patients were included. Median follow-up duration was 9.4 and 14.5 months, respectively. Median OS was 5.4 months (95%CI, 3.3–9.2) with ICIs and 8.2 months (95%CI, 6.8–10.0) with CHT. In ICI-treated patients, low albumin and metastatic disease at initial presentation were associated with worse OS [HR (95%CI) 2.15 (1.18–3.90), p =.012; 2.58 (1.30–5.10), p =.007, respectively] whereas surgery for organ-confined disease and high TMB (≥10 mut/Mb) were associated with improved OS (HR (95%CI) 0.56 (0.36–0.88), p =.012; 0.58 [0.35–0.95]; p=.03), respectively. In CHT-treated patients, those with high APOBEC had worse OS (HR 1.43 [95% CI, 1.06–1.94]; p=.02). Neither PD-L1 (HR 0.96 [0.37-2.46]; p =.93), FGFR3 mutations (HR 0.98 [0.65-1.47]; p =.92) nor DNA damage-repair pathway alterations (HR 1.06 [0.73-1.52]; p =.77) were associated with OS. A novel BIPI for ICI-treated patients combining clinical and genomic variables (non-metastatic at initial diagnosis, normal albumin level, previous surgery for organ-confined disease, high TMB) was developed. Patients were categorized in 3 groups (low, intermediate, high risk) which correlated with OS. Median OS (95%CI) for low, intermediate and high risk was 11.7 (8.9−17.7), 4.1 (2.5–NE) and 2.4 months (1.0–4.0), (p <.001). Same results were observed in the validation cohort from an independent phase II immunotherapy trial in mUC (p <.001). Conclusions: This is the first time RWD including CGP were used to develop and validate a novel BIPI in mUC. This prognostic index may help patient selection in everyday practice and inform future trial design.

Low expression of ANT1 confers oncogenic properties to rhabdomyosarcoma tumor cells by modulating metabolism and death pathways

Rhabdomyosarcoma (RMS) is the most frequent form of pediatric soft-tissue sarcoma. It is divided into two main subtypes: ERMS (embryonal) and ARMS (alveolar). Current treatments are based on chemotherapy, surgery, and radiotherapy. The 5-year survival rate has plateaued at 70% since 2000, despite several clinical trials. RMS cells are thought to derive from the muscle lineage. During development, myogenesis includes the expansion of muscle precursors, the elimination of those in excess by cell death and the differentiation of the remaining ones into myofibers. The notion that these processes may be hijacked by tumor cells to sustain their oncogenic transformation has emerged, with RMS being considered as the dark side of myogenesis. Thus, dissecting myogenic developmental programs could improve our understanding of RMS molecular etiology. We focused herein on ANT1, which is involved in myogenesis and is responsible for genetic disorders associated with muscle degeneration. ANT1 is a mitochondrial protein, which has a dual functionality, as it is involved both in metabolism via the regulation of ATP/ADP release from mitochondria and in regulated cell death as part of the mitochondrial permeability transition pore. Bioinformatics analyses of transcriptomic datasets revealed that ANT1 is expressed at low levels in RMS. Using the CRISPR-Cas9 technology, we showed that reduced ANT1 expression confers selective advantages to RMS cells in terms of proliferation and resistance to stress-induced death. These effects arise notably from an abnormal metabolic switch induced by ANT1 downregulation. Restoration of ANT1 expression using a Tet-On system is sufficient to prime tumor cells to death and to increase their sensitivity to chemotherapy. Based on our results, modulation of ANT1 expression and/or activity appears as an appealing therapeutic approach in RMS management.

Prototyping Trastuzumab Docetaxel Immunoliposomes with a New FCM-Based Method to Quantify Optimal Antibody Density on Nanoparticles

Developing targeted nanoparticles is a rising strategy to improve drug delivery in oncology. Antibodies are the most commonly used targeting agents. However, determination of their optimal number at the surface remains a challenging issue, mainly due to the difficulties in measuring precisely surface coating levels when prototyping nanoparticles. We developed an original quantitative assay to measure the exact number of coated antibodies per nanoparticle. Using flow cytometry optimized for submicron particle analysis and beads covered with known amounts of human IgG-kappa mimicking various amounts of antibodies, this new method was tested as part of the prototyping of docetaxel liposomes coated with trastuzumab against Her2+ breast cancer. This quantification method allowed to discriminate various batches of immunoliposomes depending on their trastuzumab density on nanoparticle surface (i.e., 330 (Immunoliposome-1), 480 (Immunoliposome-2) and 690 (Immunoliposome-3), p = 0.004, One-way ANOVA). Here we showed that optimal number of grafted antibodies on nanoparticles should be finely tuned and highest density of targeting agent is not necessarily associated with highest efficacy. Overall, this new method should help to better prototype third generation nanoparticles.

Intermittent Versus Continuous Dosing of MAPK Inhibitors in the Treatment of BRAF-Mutated Melanoma

The development of BRAF and MEK inhibitors (BRAFi/MEKi) has led to major advances in melanoma treatment. However, the emergence of resistance mechanisms limits the benefit duration and a complete response occurs in less than 20% of patients receiving BRAFi ± MEKi. In this study, we evaluated the impact of an intermittent versus continuous dosing schedule of BRAF/MEK inhibition in a melanoma model mildly sensitive to a BRAF inhibitor. The combination of a BRAFi with three different MEKi was studied with a continuous or intermittent dosing schedule in vivo, in a xenografted melanoma model and ex vivo using histoculture drug response assays (HDRAs) of patient-derived xenografts (PDX). To further understand the underlying molecular mechanisms of therapeutic efficacy, a biomarker pharmacodynamic readout was evaluated.

An equal impact on tumor growth was observed in monotherapy or bitherapy regimens whether we used continuous and intermittent dosing schedules, with no significant differences in biomarkers expression between the treatments. The antitumoral effect was mostly due to modulations of expression of cell cycle and apoptotic mediators. Moreover, ex vivo studies did not show significant differences between the dosing schedules.

In this context, our preclinical and pharmacodynamic results converged to show the similarity between intermittent and continuous treatments with either BRAFi or MEKi alone or with the combination of both.

Abstract 3000: Impact of trastuzumab coating when prototyping immunoliposomes in breast cancer models: The more the merrier

Background: Improving drug delivery in oncology by developing antibodies targeted nanoparticles loaded with cytotoxics is a rising strategy in oncology. Determination of the optimal density of antibodies on nanoparticles surface remains an open question, mainly due to the difficulty in measuring accurately the actual level of coating. We have developed a stealth immunoliposome encapsulating docetaxel and harboring anti-Her2 trastuzumab. To better prototyping the nanoparticles, we have developed a method for the absolute quantitation of trastuzumab, so as to compare the performance of the immunoliposomes in terms of efficacy in breast cancer depending on the number of antibodies. Methods: Using flow cytometry we have developed a quick and quantitative assay to measure the amount of trastuzumab coated per docetaxel immunoliposome. Three batches of immunoliposomes exhibiting different densities of trastuzumab were synthesized using the standard thin-film method and a maleimide linker. Quality control was operated regarding size, docetaxel encapsulation and trastuzumab coating levels, including stability studies. In vitro and in vivo efficacy studies were performed on MDA-MB-453 used as a canonical model of Her-2+ human breast cancer cells. Results: The three batches of Immunoliposomes exhibited 330 ± 30 (batch1), 480 ± 110 (batch2) and 690 ± 80 (batch3) trastuzumab IgG molecules per liposome, respectively (p&lt;0.01, One-Way Anova). In 2D apoptosis induction experiments, no difference was observed between free drugs and immunoliposomes, regardless of trastuzumab density. When shifting to 3D spheroids, higher antiproliferative efficacy was observed with batch2 as compared with other immunoliposomes or free drugs (+76%) or reference T-DM1 (+85%). Next, batch2 was further tested in mice bearing MDA-MB-453 xenografts. Immunoliposomes achieved a tumor reduction of 89 % when compared to free drugs and 66% as compared with T-DM1 (p&lt;0.05, One-Way Anova). Conclusion: Our assay based on flow cytometry of submicron particles can accurately quantify the number of coated antibodies on single nanoparticles. In vitro studies demonstrated that maximal density of targeting agent on nanoparticles was not a prerequisite for maximal therapeutic effect. In vitro spheroids and in vivo studies in mice demonstrated higher efficacy of our immunoliposomes when compared to free trastuzumab docetaxel used in combo and antibody-drug conjugate T-DM1. Beyond the current project, this new quantitation method could be valuable when prototyping nanoparticles or conjugated drugs using monoclonal antibodies as targeting agent.

Citation Format: Anne Rodallec, Corentin Franco, Stéphane Robert, Guillaume Sicard, Sarah Giacometti, Ariel Savina, Fanny Bouquet, Bruno Lacarelle, Joseph Ciccolini, Philippe Poncelet, Raphaelle Fanciullino. Impact of trastuzumab coating when prototyping immunoliposomes in breast cancer models: The more the merrier [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3000.

Temperature-dependent transport measurements with Arduino

The current performances of single-board microcontrollers render them attractive, not only for basic applications, but also for more elaborate projects, amongst which are physics teaching or research. In this article, we show how temperature-dependent transport measurements can be performed by using an Arduino board, from cryogenic temperatures up to room temperature or above. We focus on two of the main issues for this type of experiments: the determination of the sample temperature and the measurement of its resistance. We also detail two student-led experiments: evidencing the magnetocaloric effect in Gadolinium and measuring the resistive transition of a high critical temperature superconductor. Received: 7 July 2018,  Accepted: 27 September 2018; Edited by: A. Marti,  M. Monteiro;  Reviewed by: R. Marotti, Instituto de Física, Facultad de Ingeniería - Universidad de la República, Uruguay; DOI: http://dx.doi.org/10.4279/PIP.100007 Cite as: A Hilberer, G Laurent, A Lorin, A Partier, J Bobroff, F Bouquet, C Even, J M Fischbach, C A Marrache Kikuchi, M Monteverde, B Pilette, Q Quay,  Papers in Physics 10, 100007(2018) This paper, by A Hilberer, G Laurent, A Lorin, A Partier, J Bobroff, F Bouquet, C Even, J M Fischbach, C A Marrache Kikuchi, M Monteverde, B Pilette, Q Quay, is licensed under the Creative Commons Attribution License 4.0.    

From 3D spheroids to tumor bearing mice: efficacy and distribution studies of trastuzumab-docetaxel immunoliposome in breast cancer

Purpose

Nanoparticles are of rising interest in cancer research, but in vitro canonical cell monolayer models are not suitable to evaluate their efficacy when prototyping candidates. Here, we developed three-dimensional (3D) spheroid models to test the efficacy of trastuzumab-docetaxel immunoliposomes in breast cancer prior to further testing them in vivo.

Materials and methods

Immunoliposomes were synthesized using the standard thin film method and maleimide linker. Two human breast cancer cell lines varying in Her2 expression were tested: Her2+ cells derived from metastatic site: mammary breast MDA-MB-453 and triple-negative MDA-MB-231 cells. 3D spheroids were developed and tested with fluorescence detection to evaluate viability. In vivo efficacy and biodistribution studies were performed on xenograft bearing nude mice using fluorescent and bioluminescent imaging.

Results

In vitro, antiproliferative efficacy was dependent upon cell type, size of the spheroids, and treatment scheduling, resulting in subsequent changes between tested conditions and in vivo results. Immunoliposomes performed better than free docetaxel + free trastuzumab and ado-trastuzumab emtansine (T-DM1). On MDA-MB-453 and MDA-MB-231 cell growth was reduced by 76% and 25%, when compared to free docetaxel + free trastuzumab and by 85% and 70% when compared to T-DM1, respectively. In vivo studies showed tumor accumulation ranging from 3% up to 15% of the total administered dose in MDA-MB-453 and MDA-MB-231 bearing mice. When compared to free docetaxel + free trastuzumab, tumor growth was reduced by 89% (MDA-MB-453) and 25% (MDA-MB-231) and reduced by 66% (MDA-MB-453) and 29% (MDA-MB-231) when compared to T-DM1, an observation in line with data collected from 3D spheroids experiments.

Conclusion

We demonstrated the predictivity of 3D in vitro models when developing and testing nanoparticles in experimental oncology. In vitro and in vivo data showed efficient drug delivery with higher efficacy and prolonged survival with immunoliposomes when compared to current anti-Her2 breast cancer strategies.

Abstract 2888: DNA Repair Enzyme Signature as a biomarker of MAPK pathway inhibition by targeted therapies in melanoma cell lines

About 50% of melanomas carry activating mutation in BRAF or NRAS genes. BRAF/MEK inhibitors elicit a transient effective response but resistance rapidly develops through various MAPK/PI3K/AKT pathway activating mechanisms. DNA Repair mechanisms are regulated by these signaling pathways. We hypothesized that effective inhibition of the MAPK pathway should translate into decrease of DNA Repair capacities.

To gain insights into this hypothesis we measured the DNA Repair capacities of 12 melanoma cell lines treated or not by BRAF and MEK inhibitors (respectively Vemurafenib V and Cobimetinib C, Roche laboratories), alone and in combination.

We evaluated various excision synthesis repair mechanisms using a multiplexed functional DNA Repair assay using cell extracts. We thus obtained a comprehensive overview of the cell lines DNA Repair capacities.

Significant qualitative and quantitative differences were observed between the DNA Repair profiles of the 3 mutation groups in non-treated cells.

Globally DNA Repair capacities of BRAFm cells significantly decreased following treatment by V and V+C confirming that excision synthesis repair mechanisms are under the control of the MAPK pathway. When the cell lines were examined individually, interesting features were observed. 3/7 showed drastic decrease of DNA repair with V and V+C treatment. On the contrary, C alone activated repair in 3/7, possibly reflecting a paradoxical activation of some pathways.

In addition, among the 3 NRASm cell lines, only 1 exhibited a marked decreased of DNA Repair after C treatment. Surprisingly V and V+C activated some repair activities in one WT cell line, possibly reflecting some paradoxical activation of the complex kinase network.

Our results suggest that mutations in signaling kinase pathways impact the so-called DNA Damage Response and translate into specific DNA Repair Enzyme Signatures. Crosstalk of tyrosine kinases with the DNA damage signaling pathway is well known. It is possible to take advantage of their intricate regulation through characterization of DNA Repair Enzymatic Signature to gain information on the inhibition efficacy of targeted drugs.

Interestingly this approach could be conducted on clinical samples and we propose to use the DNA Repair Enzyme Signature as a new tool to investigate effectiveness of targeted therapies in metastatic melanoma.

This study was sponsored by Institut Roche.

Citation Format: Sylvie Sauvaigo, Manel Benkhiat, Florian Braisaz, Florence de Fraipont, Caroline Aspord, Stéphane Mouret, Joël Plumas, Fanny Bouquet, Marie-Thérèse Leccia. DNA Repair Enzyme Signature as a biomarker of MAPK pathway inhibition by targeted therapies in melanoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2888.

Docetaxel-trastuzumab stealth immunoliposome: development and in vitro proof of concept studies in breast cancer

Background

Trastuzumab plus docetaxel is a mainstay to treat HER2-positive breast cancers. However, developing nanoparticles could help to improve the efficacy/toxicity balance of this doublet by improving drug trafficking and delivery to tumors. This project aimed to develop an immunoliposome in breast cancer, combining docetaxel encapsulated in a stealth liposome engrafted with trastuzumab, and comparing its performances on human breast cancer cell lines with standard combination of docetaxel plus trastuzumab.

Methods

Several strategies to engraft trastuzumab to pegylated liposomes were tested. Immunoliposomes made of natural (antibody nanoconjugate-1 [ANC-1]) and synthetic lipids (ANC-2) were synthesized using standard thin film method and compared in size, morphology, docetaxel encapsulation, trastuzumab engraftment rates and stability. Antiproliferative activity was tested on human breast cancer models ranging from almost negative (MDA-MB-231), positive (MDA-MB-453) to overexpressing (SKBR3) HER2. Finally, cell uptake of ANC-1 was studied by electronic microscopy.

Results

ANC-1 showed a greater docetaxel encapsulation rate (73%±6% vs 53%±4%) and longer stability (up to 1 week) as compared with ANC-2. Both ANC presented particle size ≤150 nm and showed similar or higher in vitro antiproliferative activities than standard treatment, ANC-1 performing better than ANC-2. The IC_50s for docetaxel combined to free trastuzumab were 8.7±4, 2±0.7 and 6±2 nM with MDA-MB-231, MDA-MB-453 and SKBR3, respectively. The IC_50s for ANC-1 were 2.5±1, 1.8±0.6 and 3.4±0.8 nM and for ANC-2 were 1.8±0.3 nM, 2.8±0.8 nM and 6.8±1.8 nM with MDA-MB-231, MDA-MB-453 and SKBR3, respectively. Cellular uptake appeared to depend on HER2 expression, the higher the expression, the higher the uptake.

Conclusion

In vitro results suggest that higher antiproliferative efficacy and efficient drug delivery can be achieved in breast cancer models using nanoparticles.

Abstract P5-01-03: HER2 imaging by SPECT-CT using 111In radiolabeled pertuzumab-fab DOTAGA-conjugate: A proof of concept study in a preclinical model of breast cancer

Introduction: HER2 is positive in approximately 20-30% of all breast cancer and is associated with poor prognosis, higher mortality and higher metastatic incidence. Current diagnosis of HER2 expression relies on invasive methods requiring tissue biopsy which can lead to variable results due to inter/intra-metastatic and intratumoral heterogeneity in breast cancers. It has been recently demonstrated that HER2 molecular imaging based on pertuzumab, an antibody targeting HER2, could represent a more accurate non-invasive method to assess HER2 expression and evaluate its spatial and temporal heterogeneity. Aim: In the present study, we aimed at developing radiolabeled pertuzumab Fab fragments for HER2 imaging. Tumor uptake of radiolabeled Fab was evaluated in an animal model of HER2 breast cancer by SPECT-CT, and the impact of trastuzumab on HER2 imaging was assessed. The objective of this study was to validate the feasibility of HER2 imaging with a pertuzumab-derived probe and to evaluate the possible translation of such a probe for clinical use in patients treated or not with anti-HER2 therapy. Methods: Fab fragments of pertuzumab have been generated by papain digestion and bioconjugated with the bifunctional chelating agent DOTAGA for incorporation of Indium 111 to generate an HER2-specific probe for SPECT (111In-DOTAGA-pertuzumab-Fab). The functionality of both radiolabeled Fab and whole pertuzumab was evaluated by in vitro assays using HER2-overexpressing human breast cancer cell line (HCC1954). Tumor uptake of pertuzumab-Fab and whole pertuzumab (111In-DOTAGA-Pertuzumab) has been evaluated in Balb/c nude mice bearing BT-474 tumors with or without pre-treatment with trastuzumab for 24h. Results: In the current study we demonstrate that Fab fragments of pertuzumab keep similar HER2 binding properties than whole pertuzumab and can therefore be a suitable HER2-targeted probe. In vivo, 111In-DOTAGA-pertuzumab-Fab showed better pharmacokinetics than whole pertuzumab with faster tumor uptake and blood clearance allowing faster imaging with better tumor/blood ratio. In addition, tumor uptake of 111In-DOTAGA-pertuzumab-Fab is not modified by pre-treatment with trastuzumab. Conclusion: We assume that radiolabeled pertuzumab-Fab should be of great interest if the intention to treat is based on anti-HER2 monoclonal antibodies-based therapies rather than small molecules (e.g. lapatinib). Interestingly, pertuzumab has been shown to be also beneficial in combination with trastuzumab and chemotherapy in non-metastatic patients through its approval for the neoadjuvant treatment and very recently in the APHINITY clinical trial aiming for an approval in the adjuvant treatment of early breast cancer. These data suggest that pertuzumab will be extensively used in various HER-2 positive breast cancers underlining the interest to perform molecular imaging of HER2 expression as a predictive biomarker of efficacy.

Citation Format: Oudot A, Bellaye P-S, Vrigneaud J-M, Raguin O, Bernhard C, Dumont L, Brunotte F, Savina A, Bouquet F, Fumoleau P, Collin B. HER2 imaging by SPECT-CT using 111In radiolabeled pertuzumab-fab DOTAGA-conjugate: A proof of concept study in a preclinical model of breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-01-03.

Shifting the Balance of Activating and Inhibitory Natural Killer Receptor Ligands on BRAFV600E Melanoma Lines with Vemurafenib

Over 60% of human melanoma tumors bear a mutation in the BRAF gene. The most frequent mutation is a substitution at codon 600 (V600E), leading to a constitutively active BRAF and overactivation of the MAPK pathway. Patients harboring mutated BRAF respond to kinase inhibitors such as vemurafenib. However, these responses are transient, and relapses are frequent. Melanoma cells are efficiently lysed by activated natural killer (NK) cells. Melanoma cells express several stress-induced ligands that are recognized by activating NK-cell receptors. We have investigated the effect of vemurafenib on the immunogenicity of seven BRAF-mutated melanoma cells to NK cells and on their growth and sensitivity to NK-cell-mediated lysis. We showed that vemurafenib treatment modulated expression of ligands for two activating NK receptors, increasing expression of B7-H6, a ligand for NKp30, and decreasing expression of MICA and ULBP2, ligands for NKG2D. Vemurafenib also increased expression of HLA class I and HLA-E molecules, likely leading to higher engagement of inhibitory receptors (KIRs and NKG2A, respectively), and decreased lysis of vemurafenib-treated melanoma cell lines by cytokine-activated NK cells. Finally, we showed that whereas batimastat (a broad-spectrum matrix metalloprotease inhibitor) increased cell surface ULBP2 by reducing its shedding, vemurafenib lowered soluble ULBP2, indicating that BRAF signal inhibition diminished expression of both cell-surface and soluble forms of NKG2D ligands. Vemurafenib, inhibiting BRAF signaling, shifted the balance of activatory and inhibitory NK ligands on melanoma cells and displayed immunoregulatory effects on NK-cell functional activities. Cancer Immunol Res; 5(7); 582-93. ©2017 AACR.

Sensitization of EGFR Wild-Type Non-Small Cell Lung Cancer Cells to EGFR-Tyrosine Kinase Inhibitor Erlotinib

The benefit of EGFR-TKI in non-small cell lung cancer has been demonstrated in mutant EGFR tumors as first-line treatment but the benefit in wild-type EGFR tumors is marginal as well as restricted to maintenance therapy in pretreated patients. This work aimed at questioning the effects of cisplatin initial treatment on the EGFR pathway in non-small cell lung cancer and the functional consequences in vitro and in in vivo animal models of patient-derived xenografts (PDX). We establish here that cisplatin pretreatment specifically sensitizes wild-type EGFR-expressing cells to erlotinib, contrary to what happens in mutant EGFR cells and with a blocking EGFR antibody, both in vitro and in vivo The sensitization entails the activation of the kinase Src upstream of EGFR, thereafter transactivating EGFR through a ligand-independent activation. We propose a combination of markers that enable to discriminate between the tumors sensitized to erlotinib or not in PDX models, which should be worth testing in patients. These markers might be useful for the selection of patients who would benefit from erlotinib as a maintenance therapy. Mol Cancer Ther; 16(8); 1634-44. ©2017 AACR.

Multimodal imaging based on MRI and PET reveals [(18)F]FLT PET as a specific and early indicator of treatment efficacy in a preclinical model of recurrent glioblastoma

PURPOSE

The primary objective of this study was to compare the ability of PET and MRI biomarkers to predict treatment efficacy in a preclinical model of recurrent glioblastoma multiforme.

METHODS

MRI (anatomical, diffusion, vasculature and oxygenation) and PET ([(18)F]FDG and [(18)F]FLT) parameters were obtained 3 days after the end of treatment and compared with late tumour growth and survival.

RESULTS

Early after tumour recurrence, no effect of treatment with temozolomide combined with bevacizumab was observed on tumour volume as assessed by T2-W MRI. At later times, the treatment decreased tumour volume and increased survival. Interestingly, at the earlier time, temozolomide + bevacizumab decreased [(18)F]FLT uptake, cerebral blood volume and oedema. [(18)F]FLT uptake, oedema and cerebral blood volume were correlated with overall survival but [(18)F]FLT uptake had the highest specificity and sensitivity for the early prediction of treatment efficacy.

CONCLUSION

The present investigation in a preclinical model of glioblastoma recurrence underscores the importance of multimodal imaging in the assessment of oedema, tumour vascular status and cell proliferation. Finally, [(18)F]FLT holds the greatest promise for the early assessment of treatment efficacy. These findings may translate clinically in that individualized treatment for recurrent glioma could be prescribed for patients selected after PET/MRI examinations.

Optic neuritis revealing Kikuchi-Fujimoto disease

Kikuchi-Fujimoto disease is a rare systemic disease with uncommon neurological involvement. We report the case of a 30-year-old Asian woman who presented a rapidly progressive loss of vision. Magnetic resonance imaging (MRI) of the optic nerve revealed an inflammation of the left optic nerve with chiasmatic involvement, without any encephalic or medullar lesion. Thoracic computed tomography scan showed bilateral axillary lymphadenopathy. Analysis of a biopsy of the axillary lymph node showed typical histological findings of Kikuchi-Fujimoto disease. There was no clinical or biological sign of associated systemic lupus erythematosus. The patient spontaneously recovered normal visual acuity in 4 weeks, with resolution of MRI abnormalities. No optic neuritis relapse or neurological event occurred in a 3-year follow-up. To our knowledge this is the first case of optic neuritis associated with Kikuchi-Fujimoto disease.

Kapellasite: a kagome quantum spin liquid with competing interactions

Magnetic susceptibility, NMR, muon spin relaxation, and inelastic neutron scattering measurements show that kapellasite, Cu3Zn(OH)6Cl2, a geometrically frustrated spin-1/2 kagome antiferromagnet polymorphic with herbertsmithite, is a gapless spin liquid showing unusual dynamic short-range correlations of noncoplanar cuboc2 type which persist down to 20 mK. The Hamiltonian is determined from a fit of a high-temperature series expansion to bulk susceptibility data and possesses competing exchange interactions. The magnetic specific heat calculated from these exchange couplings is in good agreement with experiment. The temperature dependence of the magnetic structure factor and the muon relaxation rate are calculated in a Schwinger-boson approach and compared to experimental results.

Abstract 5715: Modulation of Radiation Response after TGFβ signaling Blockade in Non-small Cell Lung Cancer (NSCLC) Cell Carcinomas

Lung cancer remains one of the most prevalent and deadliest malignancies worldwide. Radiotherapy (RT) is a major therapeutic modality for inoperable non-small cell lung cancer (NSCLC). There is substantial evidence that ionizing radiation triggers activation of TGFβ especially in lung, breast and liver tumor. TGFβ inhibition prior to IR inhibits the DNA damage response in epithelial cells via blockade of ATM kinase activity (Cancer Res 62:5627, 2002; Cancer Res 66:10861, 2006) and sensitizes radiation responses in breast cancer cell lines and tumors (Clin Cancer Res 2011;17:6754-6765.). The current studies test whether TGFβ blockade prior to irradiation modulates radiation response of NSCLC cell lines, NCI-H1299, NCI-H292, H460 and Lewis Lung Cancer (LLC), assessed in vitro and in vivo. All NSCLC cell lines responded to TGFβ by phosphorylation of Smad2, which was blocked by LY364947, a small molecule TGFβ type 1 receptor inhibitor. NCI-H1299 and LLC were insensitive to TGFβ growth inhibition in vitro. LY364947 increased radiosensitivity in NCI-H1299 and H460 in clonogenic assays. Consistent with increased clonogenic cell death, TGFβ inhibition also compromised radiation-induced phosphorylation of H2AX and ATM in NCI-H1299. Treatment of cultured LLC cells with either small molecule TGFβ type 1 receptor inhibitor or TGFβ neutralizing antibody, 1D11, significantly increased LLC radiosensitivity as measured by clonogenic assay. Furthermore, C57BL mice bearing subcutaneous LLC tumors treated before and after RT with 1D11 or 13C4 isotype control antibody (20 mg/kg i.p.) resulted in greater tumor growth delay compared to RT and control antibody. Together, these data indicate that TGFβ inhibition prior to radiation attenuates DNA damage responses, enhances clonogenic cell killing, and promotes tumor growth delay. Given the recognized role of radiation-induced TGFβ in lung fibrosis, the therapeutic index for RT could be significantly increased if circumstances are defined in which TGFβ inhibition during RT both enhances lung cancer radiosensitivity and protects normal lung.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5715. doi:1538-7445.AM2012-5715

TGFβ1 inhibition increases the radiosensitivity of breast cancer cells in vitro and promotes tumor control by radiation in vivo

PURPOSE

To determine whether inhibition of TGFβ signaling prior to irradiation sensitizes human and murine cancer cells in vitro and in vivo.

EXPERIMENTAL DESIGN

TGFβ-mediated growth and Smad phosphorylation of MCF7, Hs578T, MDA-MB-231, and T47D human breast cancer cell lines were examined and correlated with clonogenic survival following graded radiation doses with and without pretreatment with LY364947, a small molecule inhibitor of the TGFβ type I receptor kinase. The DNA damage response was assessed in irradiated MDA-MB-231 cells pretreated with LY364947 in vitro and LY2109761, a pharmacokinetically stable inhibitor of TGFβ signaling, in vivo. The in vitro response of a syngeneic murine tumor, 4T1, was tested using a TGFβ neutralizing antibody, 1D11, with single or fractionated radiation doses in vivo.

RESULTS

Human breast cancer cell lines pretreated with TGFβ small molecule inhibitor were radiosensitized, irrespective of sensitivity to TGFβ growth inhibition. Consistent with increased clonogenic cell death, radiation-induced phosphorylation of H2AX and p53 was significantly reduced in MDA-MB-231 triple-negative breast cancer cells when pretreated in vitro or in vivo with a TGFβ type I receptor kinase inhibitor. Moreover, TGFβ neutralizing antibodies increased radiation sensitivity, blocked γH2AX foci formation, and significantly increased tumor growth delay in 4T1 murine mammary tumors in response to single and fractionated radiation exposures.

CONCLUSION

These results show that TGFβ inhibition prior to radiation attenuated DNA damage responses, increased clonogenic cell death, and promoted tumor growth delay, and thus may be an effective adjunct in cancer radiotherapy.

A DNA-dependent stress response involving DNA-PK occurs in hypoxic cells and contributes to cellular adaptation to hypoxia

DNA-dependent protein kinase (DNA-PK) is involved in DNA double-strand break (DSB) signalling and repair. We report that DNA-PK is activated by mild hypoxia conditions (0.1-1% O₂) as shown by (1) its autophosphorylation on Ser2056, and (2) its mobilisation from a soluble nucleoplasmic compartment to a less extractable nuclear fraction. The recruitment of DNA-PK was not followed by activation and recruitment of the XRCC4-DNA-ligase-IV complex, suggesting that DSBs are not responsible for activation of DNA-PK. To unravel the mechanism of DNA-PK activation, we show that exposure of cells to trichostatin A, a histone deacetylase inhibitor, leads to DNA-PK autophosphorylation and relocalisation to DNA. Histone acetylation (mainly H3K14) is increased in hypoxic cells and treatment with anacardic acid, an inhibitor of histone acetyl transferase, prevented both histone modifications and DNA-PK activation in hypoxic conditions. Importantly, in using either silenced DNA-PK cells or cells exposed to a specific DNA-PK inhibitor (NU7026), we demonstrated that hypoxic DNA-PK activation positively regulates the key transcription factor HIF-1 and one subsequent target gene, GLUT1. Our results show that hypoxia initiates chromatin modification and consequently DNA-PK activation, which positively regulate cellular oxygen-sensing and oxygen-signalling pathways.

Loss of ATM positively regulates the expression of hypoxia inducible factor 1 (HIF-1) through oxidative stress: Role in the physiopathology of the disease

Ataxia Telangiectasia (AT) is an autosomal recessive disorder characterized by a wide variety of progressive clinical symptoms. This includes neuronal degeneration, oculocutaneous telangiectasias, diabetes mellitus, immunodeficiency, increased risk of cancer and sensitivity to ionizing radiation. The gene mutated in this disease, ATM (Ataxia Telangiectasia Mutated), encodes a protein kinase involved in DNA double strand breaks signalling and repair. ATM deficient cells also display an increase in oxidative stress, by poorly characterized mechanism(s), which clearly contributes to the neurodegenerative aspect of the disease. Despite these advances, the occurrence of the vascular abnormalities, glucose intolerance and insulin resistance remains poorly understood. In different cellular models where ATM expression was disrupted, we demonstrated that the absence of ATM leads to an increased expression of both subunits of the transcription factor Hypoxia Inducible Factor 1 (HIF-1). We also observed enhanced trans-activating functions of HIF-1. HIF-1 is the central regulator of responses to hypoxia which induces the transcription of genes involved in angiogenesis (e.g., VEGF-Vascular Endothelial Growth Factor) and cellular metabolism (e.g., GLUT-1). Interestingly, we demonstrated that ATM disruption positively regulates both expression and function of the basal glucose transporter GLUT-1 as well as the proangiogenic factor, VEGF. In addition, our results suggest that the absence of ATM increases HIF-1 proteins biosynthesis, and this effect is dependant on the oxidative stress existing in ATM deficient cells. Our compelling results highlight a new link between ATM deficiency and the clinical features of the disease and provide a molecular link between ATM downregulation and the increase in tumor angiogenesis observed in human breast cancers.

The Loss of γH2AX Signal is a Marker of DNA Double Strand Breaks Repair Only at Low Levels of DNA Damage

The induction of DNA double-strand breaks (DSBs) by genotoxic treatment leads to high toxicity and genetic instability. Various approaches have been undertaken to quantify the number of breaks and to follow the kinetic of DSB repair. Recently, the phosphorylation of the variant histone H2AX (named gammaH2AX), quantified by specific immunodetection approaches, has provided a valuable and highly sensitive method to monitor DSBs formation. Although it is admitted that the number of gammaH2AX foci reflected that of DSBs, contradictory reports leave open the question of a link between the disappearance of gammaH2AX signal and DSBs repair. We determined gammaH2AX expression (i) in cells either proficient or not in DSBs repair capacity, (ii) after exposure to ionizing radiation (IR) or calicheamicin gamma1, a radiomimetic compound, (iii) and by three different immunodetection methods, foci numbering, flow cytometry or Western blotting. We showed here that gammaH2AX loss correlates with DSB repair activity only at low cytotoxic doses, when less than 100-150 DSBs breaks per genome are produced, independently of the method used. In addition, in DNA repair proficient cells, the early decrease in the number and intensity of gammaH2AX foci observed after a 2 Gy exposure was not associated with a significant change in the global gammaH2AX level as determined by Western blotting or flow cytometry. These results suggest that the dephosphorylation step of gammaH2AX may be limiting and that the loss of foci is mediated not only by gammaH2AX dephosphorylation but also through its redistribution towards the chromatin.

Specific heat of single crystal MgB2: a two-band superconductor with two different anisotropies

Heat-capacity measurements of a 39 microg MgB2 single crystal in fields up to 14 T and below 3 K allow the determination of the low-temperature linear term of the specific heat, its field dependence, and its anisotropy. Our results are compatible with two-band superconductivity, the band carrying the smaller gap being isotropic, that carrying the larger gap having an anisotropy of approximately 5. Three different upper critical fields are thus needed to describe the superconducting state of MgB2.

Specific heat of Mg11B2: evidence for a second energy gap

Measurements of the specific heat of Mg11B2 from 1 to 50 K, in magnetic fields to 9 T, give the Debye temperature, Theta = 1050 K, the coefficient of the normal-state electron contribution, gamma(n) = 2.6 mJ mol(-1) K-2, and a discontinuity in the zero-field specific heat of 133 mJ mol(-1) K-1 at T(c) = 38.7 K. The estimated value of the electron-phonon coupling parameter, lambda = 0.62, could account for the observed T(c) only if the important phonon frequencies are unusually high relative to Theta. At low T, there is a strongly field-dependent feature that suggests the existence of a second energy gap, about 4 times smaller than the major gap.

An unusual phase transition to a second liquid vortex phase in the superconductor YBa2Cu3O7

A magnetic field penetrates a superconductor through an array of 'vortices', each of which carries one quantum of flux that is surrounded by a circulating supercurrent. In this vortex state, the resistivity is determined by the dynamical properties of the vortex 'matter'. For the high-temperature copper oxide superconductors (see ref.1 for a theoretical review), the vortex phase can be a 'solid', in which the vortices are pinned, but the solid can 'melt' into a 'liquid' phase, in which their mobility gives rise to a finite resistance. (This melting phenomenon is also believed to occur in conventional superconductors, but in an experimentally inaccessible part of the phase diagram.) For the case of YBa2Cu3O7, there are indications of the existence of a critical point, at which the character of the melting changes. But neither the thermodynamic nature of the melting, nor the phase diagram in the vicinity of the critical point, has been well established. Here we report measurements of specific heat and magnetization that determine the phase diagram in this material to 26 T, well above the critical point. Our results reveal the presence of a reversible second-order transition above the critical point. An unusual feature of this transition-namely, that the high-temperature phase is the less symmetric in the sense of the Landau theory-is in accord with theoretical predictions of a transition to a second vortex-liquid phase.

[Ethical evaluation of biomedical research]

Every human behaviour, therefore also biomedical research, implies a reference, either implicit or explicit, to ethic values. The expression "biomedical research" attains to the domain of two distinct fields, the scientific and the technical one and this distinction is important for its ethic implications. In fact, it was the great progress in the biotechnologies that in the early 70's stimulated the birth of a new discipline known as bioethics, that from its very start was meant to be the meeting point between culturers of the biological sciences and those of human sciences. Among the paradigms adopted by bioethics, those of Beauchamp and Childress, which refer to the principles of "beneficence" (well doing), "non maleficence" (not wrong doing), autonomy and justice, are still of great importance. Bioethics proposed to establish an inequivocal and shared language and to develop adequate and rigorous procedures of analysis. So, at various levels, international, national and local, those interesting tools of the trade, which are the ethics committees, have arose. In order for an ethic committee to function, one must guarantee from the start, the conditions of autonomy and representativeness of different knowledges and cultural options that characterize our complex society. It is also necessary that an ethics committee, rather than assuming a prescriptive role, should promote attention and reflection on the ethical aspects of biomedical research.

Use of the fractal dimension for the analysis of electroencephalographic time series

Electroencephalogram (EEG) traces corresponding to different physiopathological conditions can be characterized by their fractal dimension, which is a measure of the signal complexity. Generally this dimension is evaluated in the phase space by means of the attractor dimension or other correlated parameters. Nevertheless, to obtain reliable values, long duration intervals are needed and consequently only long-term events can be analysed; also much calculation time is required. To analyse events of brief duration in real-time mode and to apply the results obtained directly in the time domain, thus providing an easier interpretation of fractal dimension behaviour, in this work we optimize and propose a new method for evaluating the fractal dimension. Moreover, we study the robustness of this evaluation in the presence of white or line noises and compare the results with those obtained with conventional spectral methods. The non-linear analysis carried out allows us to investigate relevant EEG events shorter than those detectable by means of other linear and non-linear techniques, thus achieving a better temporal resolution. An interesting link between the spectral distribution and the fractal dimension value is also pointed out.

Endozepine stupor in children

Recurring episodes of stupor in adults have been shown to be related to increased levels of endozepines, which are endogenous ligands for the GABAA receptors. We report here two children presenting with recurrent episodes of stupor associated with fast EEG activity who had increased levels of endozepine-4 in plasma. Mass spectroscopy did not reveal commercially available benzodiazepines. Interictal endozepine-4 levels were normal. In one of the patients, administration of flumazenil (0.25 mg i.v.), a benzodiazepine inverse agonist, induced improvement of consciousness and attenuation of EEG fast activity. In conclusion, children presenting with recurrent episodes of stupor and EEG fast activity should be evaluated for endozepine levels and can be effectively treated with i.v. flumazenil.

Coeliac disease, epilepsy, and cerebral calcifications. The Italian Working Group on Coeliac Disease and Epilepsy

There have been anecdotal reports of an association between coeliac disease and epilepsy with cerebral calcifications that resemble those of the Sturge-Weber syndrome. A series of patients who had epilepsy with calcifications, in whom coeliac disease (CD) was incidentally observed, prompted us to study this association. 43 patients (15 male, age range 4.6-30.7 years) were selected from two series. 31 patients with cerebral calcifications of unexplained origin and epilepsy (series A) underwent intestinal biopsy. 12 patients with CD and epilepsy (series B) underwent computed tomography. Antibodies to gluten, folic acid serum concentrations, were measured, and HLA typing was done in most patients. 24 of the series A patients were identified as having CD on the basis of a flat intestinal mucosa (15/22 with a high concentration of serum antigluten), and 5 series B patients showed cerebral calcifications, giving a total of 29 cases with the combination of CD, epilepsy, and cerebral calcifications (CEC). In 27 of these CEC patients, calcifications were located in the parieto-occipital regions. Only 2 of the series A patients had gastrointestinal symptoms at the time of intestinal biopsy; most patients had recurrent diarrhoea, anaemia, and other symptoms suggestive of CD in the first 3 years of life. The epilepsy in CEC patients was poorly responsive to antiepileptic drugs. Gluten-free diet beneficially affected the course of epilepsy only when started soon after epilepsy onset. Cases of "atypical Sturge-Weber syndrome" (characterised by serpiginous cerebral calcifications and epilepsy without facial port-wine naevus) should be reviewed, and CD should be ruled out in all cases of epilepsy and cerebral calcifications of unexplained origin.

Coeliac disease, folic acid deficiency and epilepsy with cerebral calcifications

Two cases of focal occipital epilepsy with cerebral calcifications poorly responsive to antiepileptic treatment are described. In both cases coeliac disease was diagnosed and folic acid deficiency documented. A gluten-free diet and a brief supplementation with folic acid lead to a complete EEG and clinical normalization in one case and to a significant improvement of EEG and seizure control in the other.

[Recurrent iatrogenic benign intracranial hypertension in a case of congenital adrenogenital syndrome with loss of salts]

Pseudotumor cerebri is a condition that produces symptoms and signs of brain tumor; the increased intracranial pressure is caused by diffuse cerebral edema. The authors describe a case of 12 years boy, with adrenal hyperplasia, treated by DOCA, presenting recurrent episodes of hyponatremia, headache, nausea and papilledema, cured definitively after correction of natremia and after institution 9-alpha-fluorohydrocortisone therapy.