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Glioblastoma multiforme is characterized in part by severe hypoxia associated with tumor necrosis. The cellular response to hypoxia can influence several properties of tumor cells associated with aggressive tumor growth, including metabolic adaptations and tumor cell migration and invasion. Here, we found that Delta Like Non-Canonical Notch Ligand 1 (DLK1) expression was elevated as compared with normal brain in a genetically engineered mouse model of glioma, and that DLK1 expression increased with tumor grade in human glioma samples. DLK1 expression was highest in hypoxic and perivascular tumor areas, and we found that hypoxia induced the release and nuclear translocation of an intracellular fragment of DLK1 in murine glioma as well as in human glioma cultures. Release of the intracellular fragment was dependent on ADAM17 and Hypoxia-inducible Factor 1alpha and 2alpha (HIF-1alpha/HIF-2alpha), as ADAM17 inhibitors and HIF1A/HIF2A siRNA blocked DLK1 cleavage. Expression of a cleavable form of DLK1 amplified several hypoxia-induced traits of glioma cells such as colony formation, stem cell marker gene expression, a PI3K-pathway-mediated metabolic shift, and enhanced invasiveness. Effects of DLK1 were dependent on DLK1-cleavage by ADAM17, as expression of non-cleavable DLK1 could not replicate the DLK1-induced hypoxic phenotype. Finally, forced expression of DLK1 resulted in more invasive tumor growth in a PDGFB-induced glioma mouse model without affecting overall survival. Together, our findings suggest a previously undescribed role for DLK1 as an intracellular signaling molecule.

DLK1 is a maternally imprinted, paternally expressed gene coding for the transmembrane protein Delta-like homologue 1 (DLK1), a non-canonical NOTCH ligand with well-described roles during development, and tumor-supportive functions in several aggressive cancer forms. Here, we review the many functions of DLK1 as a regulator of stem cell pools and tissue differentiation in tissues such as brain, muscle, and liver. Furthermore, we review recent evidence supporting roles for DLK1 in the maintenance of aggressive stem cell characteristics of tumor cells, specifically focusing on central nervous system tumors, neuroblastoma, and hepatocellular carcinoma. We discuss NOTCH -dependent as well as NOTCH-independent functions of DLK1, and focus particularly on the complex pattern of DLK1 expression and cleavage that is finely regulated from a spatial and temporal perspective. Progress in recent years suggest differential functions of extracellular, soluble DLK1 as a paracrine stem cell niche-secreted factor, and has revealed a role for the intracellular domain of DLK1 in cell signaling and tumor stemness. A better understanding of DLK1 regulation and signaling may enable therapeutic targeting of cancer stemness by interfering with DLK1 release and/or intracellular signaling.

Background:Loss-of-function mutations of thyrotropin receptor (TSHR) are one of the main causes of congenital hypothyroidism. As for many disease-associated G-protein coupled receptors (GPCRs), these mutations often affect the correct trafficking and maturation of the receptor, thus impairing the expression on the cell surface. Several retained GPCR mutants are able to effectively bind their ligands and to transduce signals when they are forced to the cell surface by degradation inhibition or by treatment with chaperones. Despite the large number of well-characterized retained TSHR mutants, no attempts have been made for rescue. Further, little is known about TSHR degradation pathways. We hypothesize that, similar to other GPCRs, TSHR retained mutants may be at least partially functional if their maturation and membrane expression is facilitated by chaperones or degradation inhibitors.Methods:We performedin silicopredictions of the functionality of known TSHR variants and compared the results with availablein vitrodata. Western blot, confocal microscopy, enzyme-linked immunosorbent assays, and dual luciferase assays were used to investigate the effects of degradation pathways inhibition and of chemical chaperone treatments on TSHR variants' maturation and functionality.Results:We found a high discordance rate betweenin silicopredictions andin vitrodata for retained TSHR variants, a fact indicative of a conserved potential to initiate signal transduction if these mutants were expressed on the cell surface. We show experimentally that some maturation defective TSHR mutants are able to effectively transduce Gs/cAMP signaling if their maturation and expression are enhanced by using chemical chaperones. Further, through the characterization of the intracellular retained p.N432D variant, we provide new insights on the TSHR degradation mechanism, as our results suggest that aggregation-prone mutant can be directed toward the autophagosomal pathway instead of the canonical proteasome system.Conclusions:Our study reveals alternative pathways for TSHR degradation. Retained TSHR variants can be functional when expressed on the cell surface membrane, thus opening the possibility of further studies on the pharmacological modulation of TSHR expression and functionality in patients in whom TSHR signaling is disrupted.

Thyroid cancer (TC) is the most common endocrine malignancy. Recent progress in thyroid cancer biology revealed a certain degree of intratumoral heterogeneity, highlighting the coexistence of cellular subpopulations with distinct proliferative capacities and differentiation abilities. Among those subpopulations, cancer stem-like cells (CSCs) are hypothesized to drive TC heterogeneity, contributing to its metastatic potential and therapy resistance. CSCs principally exist in tumor areas with specific microenvironmental conditions, the so-called stem cell niches. In particular, in thyroid cancer, CSCs’ survival is enhanced in the hypoxic niche, the immune niche, and some areas with specific extracellular matrix composition. In this review, we summarize the current knowledge about thyroid CSCs, the tumoral niches that allow their survival, and the implications for TC therapy.

Introduction: Neuroendocrine transdifferentiation (NED) of prostate cancer (PC) cells is associated with the development of resistance to antiandrogen therapy and poor prognosis in patients with castration-resistant PC (CRPC). Many of the molecular events, involved in NED, appear to be mediated by epigenetic mechanisms. In this study, we evaluated the antitumor activity and epigenetic modulation of 2 epigenetic drugs, such as the demethylating agent 5-aza-2′-deoxycytidine (AZA) and the methyl donor S-adenosylmethionine (SAM), in 2 human CRPC cell lines with NED (DU-145 and PC-3). Methods: The effects of AZA and SAM on cell viability, cell cycle, apoptosis, migration, and genome-wide DNA methylation profiling have been evaluated. Results: Both drugs showed a prominent antitumor activity in DU-145 and PC-3 cells, through perturbation of cell cycle progression, induction of apoptosis, and inhibition of cell migration. AZA and SAM reversed NED in DU-145 and PC-3, respectively. Moreover, AZA treatment modified DNA methylation pattern in DU-145 cells, sustaining a pervasive hypomethylation of the genome, with a relevant effect on several pathways involved in the regulation of cell proliferation, apoptosis, and cell migration, in particular Wnt/β-catenin. Conclusions: A relevant antitumor activity of these epigenetic drugs on CRPC cell lines with NED opens a new scenario in the therapy of this lethal variant of PC.

Background Internal dosimetry evaluation consists of a multi-step process ranging from imaging acquisition to absorbed dose calculations. Assessment of uncertainty is complicated and, for that reason, it is commonly ignored in clinical routine. However, it is essential for adequate interpretation of the results. Recently, the EANM published a practical guidance on uncertainty analysis for molecular radiotherapy based on the application of the law of propagation of uncertainty. In this study, we investigated the overall uncertainty on a sample of a patient following the EANM guidelines. The aim of this study was to provide an indication of the typical uncertainties that may be expected from performing dosimetry, to determine parameters that have the greatest effect on the accuracy of calculations and to consider the potential improvements that could be made if these effects were reduced. Results Absorbed doses and the relative uncertainties were calculated for a sample of 49 patients and a total of 154 tumours. A wide range of relative absorbed dose uncertainty values was observed (14–102%). Uncertainties associated with each quantity along the absorbed dose calculation chain (i.e. volume, recovery coefficient, calibration factor, activity, time-activity curve fitting, time-integrated activity and absorbed dose) were estimated. An equation was derived to describe the relationship between the uncertainty in the absorbed dose and the volume. The largest source of error was the VOI delineation. By postulating different values of FWHM, the impact of the imaging system spatial resolution on the uncertainties was investigated. Discussion To the best of our knowledge, this is the first analysis of uncertainty in molecular radiotherapy based on a cohort of clinical cases. Wide inter-lesion variability of absorbed dose uncertainty was observed. Hence, a proper assessment of the uncertainties associated with the calculations should be considered as a basic scientific standard. A model for a quick estimate of uncertainty without implementing the entire error propagation schema, which may be useful in clinical practice, was presented. Ameliorating spatial resolution may be in future the key factor for accurate absorbed dose assessment.

Tumor cell behaviors associated with aggressive tumor growth such as proliferation, therapeutic resistance, and stemness are regulated in part by soluble factors derived from the tumor microenvironment. Tumor-associated astrocytes represent a major component of the glioma tumor microenvironment, and astrocytes have an active role in maintenance of normal neural stem cells in the stem cell niche, in part via secretion of soluble Delta-like Non-Canonical Notch Ligand 1 (DLK1). We found that astrocytes, when exposed to stresses of the tumor microenvironment such as hypoxia or ionizing radiation (IR), increased secretion of soluble DLK1. Tumor-associated astrocytes in a glioma mouse model expressed DLK1 in perinecrotic (hypoxic) and perivascular tumor areas. Glioma cells exposed to recombinant DLK1 displayed increased proliferation, enhanced sphere and colony formation abilities, and increased levels of stem cell marker genes. Mechanistically, DLK1-mediated effects on glioma cells involved increased and prolonged stabilization of Hypoxia-Inducible Factor 2alpha (HIF-2alpha), and inhibition of HIF-2alpha activity abolished effects of DLK1 in hypoxia. Forced expression of soluble DLK1 resulted in more aggressive tumor growth and shortened survival in a genetically engineered mouse model of glioma. Together, our data support DLK1 as a soluble mediator of glioma aggressiveness derived from the tumor microenvironment.Graphical abstractHighlightsAstrocytes secrete DLK1 after exposure to hypoxia or irradiationSoluble DLK1 promotes stemness in glioma, in part by increasing HIF-2alpha stabilization.High levels of soluble DLK1 are associated with tumor aggressiveness and lethality.

Aim\ud The present work concerns the comparison of the performances of three systems for dosimetry in RPT that use different techniques for absorbed dose calculation (organ-level dosimetry, voxel-level dose kernel convolution and Monte Carlo simulations). The aim was to assess the importance of the choice of the most adequate calculation modality, providing recommendations about the choice of the computation tool.\ud \ud Methods\ud The performances were evaluated both on phantoms and patients in a multi-level approach. Different phantoms filled with a 177Lu-radioactive solution were used: a homogeneous cylindrical phantom, a phantom with organ-shaped inserts and two cylindrical phantoms with inserts different for shape and volume. A total of 70 patients with NETs treated by PRRT with 177Lu-DOTATOC were retrospectively analysed.\ud \ud Results\ud The comparisons were performed mainly between the mean values of the absorbed dose in the regions of interest. A general better agreement was obtained between Dose kernel convolution and Monte Carlo simulations results rather than between either of these two and organ-level dosimetry, both for phantoms and patients. Phantoms measurements also showed the discrepancies mainly depend on the geometry of the inserts (e.g. shape and volume). For patients, differences were more pronounced than phantoms and higher inter/intra patient variability was observed.\ud \ud Conclusion\ud This study suggests that voxel-level techniques for dosimetry calculation are potentially more accurate and personalized than organ-level methods. In particular, a voxel-convolution method provides good results in a short time of calculation, while Monte Carlo based computation should be conducted with very fast calculation systems for a possible use in clinics, despite its intrinsic higher accuracy. Attention to the calculation modality is recommended in case of clinical regions of interest with irregular shape and far from spherical geometry, in which Monte Carlo seems to be more accurate than voxel-convolution methods.

In spite of the hazard due to the radiation exposure, preparation of 90Y- and 177Lu-labelled radiopharmaceuticals is still mainly performed using manual procedures. In the present study the performance of a commercial automatic synthesizer based on disposable cassettes for the labelling of 177Lu- and 90Y-DOTA-conjugated biomolecules (namely, DOTATOC and PSMA-617) was evaluated and compared to a manual and a semiautomated approach. The dose exposure of the operators was evaluated as well. More than 300 clinical preparations of both 90Y- and 177Lu-labelled radiopharmaceuticals have been performed using the three different methods. The mean radiochemical yields for 90Y-DOTATOC were 96.2±4.9%, 90.3±5.6%, and 82.0±8.4%, while for 177Lu-DOTATOC they were 98.3% ± 0.6, 90.8% ± 8.3, and 83.1±5.7% when manual, semiautomated, and automated approaches were used, respectively. The mean doses on the whole hands for yttrium-90 preparations were 0.15±0.4 mSv/GBq, 0.04±0.1 mSv/GBq, and 0.11±0.3 mSv/GBq for manual, semiautomated, and automated synthesis, respectively, and for lutetium-177 preparations, they were 0.02±0.008 mSv/GBq, 0.01±0.03 mSv/GBq, and 0.01±0.02 mSv/GBq, respectively. In conclusion, the automated approach guaranteed reliable and reproducible preparations of pharmaceutical grade therapeutic radiopharmaceuticals in a decent RCY. The radiation exposure of the operators remained comparable to the manual approach mainly due to the fact that a dedicated shielding was still not available for the system.

Medullary thyroid cancer (MTC) is a tumor highly resistant to chemo-and radiotherapy. Drug resistance can be induced by epigenetic changes such as aberrant DNA methylation. To overcome drug resistance, we explored a promising approach based on the use of 5-aza-2'-deoxycytidine (AZA), a demethylating agent, in combination with the mTOR inhibitor everolimus in MTC cells (MZ-CRC-1 and TT). This combined treatment showed a strong synergistic antiproliferative activity through the induction of apoptosis. The effect of everolimus and/or AZA on genome-wide expression profiling was evaluated by Illumina BeadChip in MZ-CRC-1 cells. An innovative bioinformatic pipeline identified four potential molecular pathways implicated in the synergy between AZA and everolimus: PI3K-Akt signaling, the neurotrophin pathway, ECM/receptor interaction, and focal adhesion. Among these, the neurotrophin signaling pathway was most directly involved in apoptosis, through the overexpression of NGFR and Bax genes. The increased expression of genes involved in the NGFRMAPK10-TP53-Bax/Bcl2 pathway during incubation with AZA plus everolimus was validated by western blotting in MZ-CRC-1 cells. Interestingly, addition of a neutralizing anti-NGFR antibody inhibited the synergistic cytotoxic activity between AZA and everolimus. These results open a new therapeutic scenario for MTC and potentially other neuroendocrine tumors, where therapy with mTOR inhibitors is currently approved. This study was funded by the Italian Ministry of Education, University and Research (Grant Number: FIRB RBAP11884M), to GV and MC. The study was partially supported by funds of the Ricerca Corrente of Istituto Auxologico Italiano, Milan, Italy (code: 05C205_2012), to GV, and MIMOmics Grant of the European Union's Seventh Framework Programme (Grant Number: 305280).

Multicellular three-dimensional (3D) spheroids represent an experimental model that is intermediate in its complexity between monolayer cultures and patients’ tumor. In the present study, we characterize multicellular spheroids from papillary (PTC) and follicular (FTC) thyroid cancers and from the corresponding normal tissues. We show that these 3D structures well recapitulate the features of the original tissues, in either the differentiated and “stem-like” components. As a second step, we were aimed to test the effects of a small multikinase inhibitor, SP600125 (SP), previously shown to efficiently induce cell death in undifferentiated thyroid cancer monolayer cultures. We demonstrate the potent effect of SP on cell growth and survival in our 3D multicellular cultures. SP exerts its main effects through direct and highly significant inhibition of the ROCK pathway, known to be involved in the regulation of cell migration and β-catenin turnover. Consistently, SP treatment resulted in a significant decrease in β-catenin levels with respect to basal conditions in tumor but not in normal spheroids, indicating that the effect is promisingly selective on tumor cells. In conclusion, we provide the morphological and molecular characterization of thyroid normal and tumor spheroids. In this 3D model we tested in vitro the effects of the multikinase inhibitor SP and further characterized its mechanism of action in both normal and tumor spheroids, thus making it an ideal candidate for developing new drugs against thyroid cancer.

The main purpose of our work was to evaluate the effects of different cyclic adenosine monophosphate analogs on thyroid cancer-derived cell lines. In particular we studied 8-chloroadenosine-3',5'-cyclic monophosphate, the most powerful cyclic adenosine monophosphate analog, and the protein kinase A I-selective combination of 8-hexylaminoadenosine-3',5'cyclic monophosphate and 8-piperidinoadenosine-3',5'-cyclic monophosphate. The cyclic adenosine monophosphate/protein kinase A pathway plays a fundamental role in the regulation of thyroid cells growth. Site-selective cyclic adenosine monophosphate analogs are a class of cyclic adenosine monophosphate-derivate molecules that has been synthesized to modulate protein kinase A activity. Although the cyclic adenosine monophosphate/protein kinase A pathway plays a fundamental role in the regulation of thyroid cells proliferation, there are currently no studies exploring the role of cyclic adenosine monophosphate analogs in thyroid cancer. We evaluated the effects on cell proliferation, apoptosis activation and alterations of different intracellular pathways using 3-(4,5-dimetylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytofluorimetry, western blotting, and kinase inhibitors. Our results show that both compounds have antiproliferative potential. Both treatments were able to modify protein kinase A RI/RII ratio, thus negatively influencing cancer cells growth. Moreover, the two treatments differentially modulated various signaling pathways that regulate cell proliferation and apoptosis. Both treatments demonstrated interesting characteristics that prompt further studies aiming to understand the intimate interaction between different intracellular pathways and possibly develop novel anticancer therapies for undifferentiated thyroid cancer.

The oncogenic activation of the rearranged during transfection (RET) proto-oncogene has a main role in the pathogenesis of medullary thyroid cancer (MTC). Several lines of evidence suggest that RET function could be influenced by cyclic AMP (cAMP)-dependent protein kinase A (PKA) activity. We evaluated the in vitro anti-tumor activity of 8-chloroadenosine-3',5'-cyclic monophosphate (8-Cl-cAMP) and PKA type I-selective cAMP analogs [equimolar combination of the 8-piperidinoadenosine-3',5'-cyclic monophosphate (8-PIP-cAMP) and 8-hexylaminoadenosine-3',5'-cyclic monophosphate (8-HA-cAMP) in MTC cell lines (TT and MZ-CRC-1)]. 8-Cl-cAMP and the PKA I-selective cAMP analogs showed a potent anti-proliferative effect in both cell lines. In detail, 8-Cl-cAMP blocked significantly the transition of TT cell population from G2/M to G0/G1 phase and from G0/G1 to S phase and of MZ-CRC-1 cells from G0/G1 to S phase. Moreover, 8-Cl-cAMP induced apoptosis in both cell lines, as demonstrated by FACS analysis for annexin V-FITC/propidium iodide, the activation of caspase-3 and PARP cleavage. On the other hand, the only effect induced by PKA I-selective cAMP analogs was a delay in G0/G1-S and S-G2/M progression in TT and MZ-CRC-1 cells, respectively. In conclusion, these data demonstrate that cAMP analogs, particularly 8-Cl-cAMP, significantly suppress in vitro MTC proliferation and provide rationale for a potential clinical use of cAMP analogs in the treatment of advanced MTC.

Stem-like glioma cells have been proposed to reside in hypoxic and/or perivascular tumor niches. Such cells display an amplified cellular response to hypoxia, and appear to have a pseudo-hypoxic phenotype both at normoxia in vitro, and in a well-oxygenated perivascular niche in vivo. Hypoxia-inducible factors are central to maintaining several properties of stem cells, but little is known about differential HIF regulation in stem vs. bulk glioma cells. Using mouse models of high-grade glioma, together with primary cultures of human glioma cells, we have identified novel cell surface regulators of hypoxic and pseudo-hypoxic phenotypes in glioma, with differential expression in stem vs. bulk glioma cells. Gamma-secretase dependent release of the intracellular domains (ICDs) of both CD44 and p75NTR was enhanced at hypoxia, and signaling from these ICDs differentially regulated HIF-1alpha and HIF-2alpha to tune the hypoxic and pseudo-hypoxic glioma phenotype independently of oxygen tension. Forced expression of the CD44 and p75NTR ICDs was sufficient to induce hypoxia signaling at oxygen tensions relevant to the perivascular niche, and inhibition of ICD release was sufficient to block hypoxia-induced stem cell characteristics of cultured glioma cells. Together, our data indicate that some markers of stem-like cells can actively contribute to the stem cell character of perivascular and perinecrotic glioma cells, by modulating the cellular response to hypoxia.

Hypoxia-inducible factors enhance glioma stemness, and glioma stem cells have an amplified hypoxic response despite residing within a perivascular niche. Still, little is known about differential HIF regulation in stem versus bulk glioma cells. We show that the intracellular domain of stem cell marker CD44 (CD44ICD) is released at hypoxia, binds HIF-2α (but not HIF-1α), enhances HIF target gene activation, and is required for hypoxia-induced stemness in glioma. In a glioma mouse model, CD44 was restricted to hypoxic and perivascular tumor regions, and in human glioma, a hypoxia signature correlated with CD44. The CD44ICD was sufficient to induce hypoxic signaling at perivascular oxygen tensions, and blocking CD44 cleavage decreased HIF-2α stabilization in CD44-expressing cells. Our data indicate that the stem cell marker CD44 modulates the hypoxic response of glioma cells and that the pseudo-hypoxic phenotype of stem-like glioma cells is achieved by stabilization of HIF-2α through interaction with CD44, independently of oxygen.

Background Multicellular spheroids represent an interesting experimental model with promising applications in the pre-clinical studies on anticancer drugs. We recently demonstrated that thyroid spheroids recapitulate the features of the original tissues, in either the differentiated and "stem-like" components. Here we were aimed to characterize thyroid spheroids and to investigate in vivo the proangiogenic potential of patient-derived xenografts (PDX) of spheroids obtained from papillary thyroid cancer (PTC) and the matched normal tissues. Methods Spheroids cultures were obtained from 11 PTCs and matched normal tissues and characterized by immunohistochemistry. The expression of p53, involved in the regulation of stem cell homeostasis, was evaluated. The proangiogenic effect of thyroid spheroids was assessed by the injection in zebrafish embryos. Results Thyroid spheroids are enriched in stem-like cells, as shown by the positivity for the stem cell marker OCT4, and by the low level of p53 expression. Interestingly, PTCs and normal thyroid tissues have a detectable p53 expression, whereas the derived spheroids are mainly constituted by cells that express p53 at a lower level. Finally, we show that PDXs derived from PTC or normal spheroids stimulate the migration and the growth of sprouting vessels toward the implant into the zebrafish embryos. Conclusions We report the characterization of multicellular spheroids obtained from PTCs and normal thyroid tissues, showing that they are enriched in stem-like cells. Moreover, we established xenografts of spheroids in zebrafish, demonstrating that they stimulate neoangiogenesis. This in vivo model could be considered as a valuable platform to test the effects of anticancer drugs.

PURPOSE: Type I interferons (IFN-α and IFN-β) are a class of cytokines that exert several biological activities, such as modulation of cell proliferation and differentiation and of the immune system. Although these cytokines interact with a common receptor complex, IFN-β showed a more potent antitumor activity than IFN-α in several tumor models. New recombinant human IFN-β products, such as IFN-β1a and IFN-β1b, have been produced in order to improve the stability and bioavailability of natural IFN-β. In this report, we analyzed the effects of recombinant IFN-β1a on the cell proliferation of two human androgen-resistant prostate cancer cell lines with neuroendocrine differentiation (DU-145, PC-3) and related mechanisms of action. METHODS: The effects of IFN-β1a on the cell growth proliferation, cell cycle, and apoptosis have been evaluated in DU-145 and PC-3 cells through MTT assay, DNA flow cytometry with propidium iodide, and Annexin V-FITC/propidium iodide staining, respectively. Moreover, the expression of neuron-specific enolase (NSE), cleaved caspase-3, caspase-8, and PARP was evaluated through Western blotting. RESULTS: IFN-β1a showed a significant anti-proliferative activity in both androgen-resistant cell lines. This effect was related to cell cycle perturbation and induction in apoptosis, as shown by flow cytometric analysis, the activation of caspase-3 and caspase-8 and PARP cleavage during incubation with IFN-β1a. Moreover, this cytokine reduced the expression of NSE in both cell lines. CONCLUSIONS: Recombinant IFN-β1a (Rebif) showed a potent in vitro anti-proliferative activity in androgen-resistant prostate cancer cells, and it could represent a promising tool for the treatment of this tumor.

Purpose Peptide Receptor Radionuclide Therapy (PPRT) is nowadays the most effective therapy for treating patients who suffered of neuroendocrine tumours [1] . In clinical practice, absorbed dose calculations are computed based on the Medical Internal Radiation Dose (MIRD) scheme (not planned or optimised for patients’ specific characteristics). To increase the quality and the efficacy of the clinical trials, a more accurate 3D dosimetry is required. Monte Carlo (MC) techniques showed to provide the most accurate approach for the MRT dose calculations. In this work, Raydose MC based pipeline [2] was used to compute the patient specific dose calculation for a clinical trial in PRRT. The dose obtained for lesions and organs at risk (OARs) were then compared to the ones based on the MIRD scheme. Methods One hundred patients were enrolled as part of a clinical trial in PRRT with a prescribed activity between 3.7 and 5.5 GBq of 177Lu-DOTA-Tyr3-octreotide. Patients were scanned five times with a SPECT/CT scanner and the sequential scans were co-registered using a non-rigid registration algorithm [3] . Volumes of interest (VOIs) including lesions and OARs were manually outlined on fused images. 3D dose maps calculated with Raydose were compared to the corresponding ones obtained with OLINDA/EXM software. Differences between calculations were evaluated using a paired samples Wilcoxon-Mann-Witney test (two-sided, p Results Mean doses calculated with OLINDA/EXM were higher than the corresponding mean doses calculated with Raydose. In particular, for the structures studied, the following median percentage differences were obtained: kidneys, −11.70% (Internal Quartile Range (IQR) = 7.14); liver, −14.06% (IQR = 5.62); spleen, −12.50% (IQR = 6.38); lesions, −21.01% (IQR = 18.52). Furthermore, significant differences were observed for kidneys and lesions. Conclusions Dose values obtained with the MC method suggested an underestimation of the dose calculated for OARs and lesions in PRRT treatment. A more accurate patient specific 3D dose calculation could be used to increase the injected activity and to rise the efficiency of the treatment but maintaining a safe level of toxicity.

Accurate delineation of the gross tumour volume (GTV) in radiation therapy process is mandatory, especially when sophisticated techniques for radiotherapy delivery are used. Functional imaging, particularly PET and its fusion with anatomical modalities, such as PET/CT, promises to improve detection and characterization of disease. Quantitative accuracy in PET imaging is affected by several factors, which influence PET data so as to accurately delineate volume for radiotherapy planning purpose. Several strategies in using PET for target volume definition in radiotherapy treatment planning are being explored in the last years. In the present paper we give an overview of different techniques proposed to generate PET-based tumour volumes and the potential of their use in the radiation oncology process.

Autonomous thyroid adenomas (ATAs) are a frequent cause of hyperthyroidism. Mutations in the genes encoding the TSH receptor (TSHR) or the Gs protein alpha subunit (GNAS) are found in approximately 70% of ATAs. The involvement of other genes and the pathogenesis of the remaining cases are presently unknown. Here, we performed whole-exome sequencing in 19 ATAs that were paired with normal DNA samples and identified a recurrent hot-spot mutation (c.1712A>G; p.Gln571Arg) in the enhancer of zeste homolog 1 (EZH1) gene, which codes for a catalytic subunit of the polycomb complex. Targeted screening in an independent cohort confirmed that this mutation occurs with high frequency (27%) in ATAs. EZH1 mutations were strongly associated with known (TSHR, GNAS) or presumed (adenylate cyclase 9 [ADCY9]) alterations in cAMP pathway genes. Furthermore, functional studies revealed that the p.Gln571Arg EZH1 mutation caused increased histone H3 trimethylation and increased proliferation of thyroid cells. In summary, this study revealed that a hot-spot mutation in EZH1 is the second most frequent genetic alteration in ATAs. The association between EZH1 and TSHR mutations suggests a 2-hit model for the pathogenesis of these tumors, whereby constitutive activation of the cAMP pathway and EZH1 mutations cooperate to induce the hyperproliferation of thyroid cells. IZKF Wurzburg [B-281]; ERA-NET E-Rare [01GM1407B]; Deutsche KrebshilfeDeutsche Krebshilfe [109994]; Wilhelm Sander Stiftung [2013.010.1] We wish to thank Eileen Bosenberg, Bianca Klupfel, and Ines Elsner for technical support and Ulrike Zabel for DNA cloning. This study was partially supported by grants from the IZKF Wurzburg (B-281, to DC and MF); the ERA-NET E-Rare (01GM1407B, to MF and DC); the Deutsche Krebshilfe (109994, to ME); and the Wilhelm Sander Stiftung (project 2013.010.1, to RP).

Thyroid cancer is the most common endocrine malignancy with increasing incidence worldwide. The majority of thyroid cancer cases are well differentiated with favorable outcome. However, undifferentiated thyroid cancers are one of the most lethal human malignancies because of their invasiveness, metastatization and refractoriness even to the most recently developed therapies. In this study we show for the first time a significant hyperactivation of ROCK/HDAC6 pathway in thyroid cancer tissues, and its negative correlation with p53 DNA binding ability. We demonstrate that a small compound, SP600125 (SP), is able to induce cell death selectively in undifferentiated thyroid cancer cell lines by specifically acting on the pathogenic pathways of cancer development. In detail, SP acts on the ROCK/HDAC6 pathway involved in dedifferentiation and invasiveness of undifferentiated human cancers, by restoring its physiological activity level. As main consequence, cancer cell migration is inhibited and, at the same time, cell death is induced through the mitotic catastrophe. Moreover, SP exerts a preferential action on the mutant p53 by increasing its DNA binding ability. In TP53-mutant cells that survive mitotic catastrophe this process results in p21 induction and eventually lead to premature senescence. In conclusion, SP has been proved to be able to simultaneously block cell replication and migration, the two main processes involved in cancer development and dissemination, making it an ideal candidate for developing new drugs against anaplastic thyroid cancer., SCOPUS: ar.j, info:eu-repo/semantics/published

Context Congenital hypothyroidism (CH) is one of the most common inborn endocrine disorders with genetic background. Despite the well-established newborn CH screening program in Hungary, no systematic examination of the underlying genetic alterations has been performed yet. Objective We aimed to explore thyrotropin receptor (TSHR) mutations in a cohort of Hungarian patients with CH. Patients 85 unrelated patients with permanent primary CH, all diagnosed at newborn screening, were selected. Main outcome measures Coding exons of the TSHR gene were sequenced and evaluated together with the thyroid-specific clinical parameters. Functional features of the novel mutations were experimentally examined, and their comparative molecular models were built. Results In 4 patients (one heterozygous and three compound heterozygous) 7 TSHR mutations were identified. Among these N4321.50D and P4492.39L are novel missense alterations. Importantly, the N4321.50 residue is highly conserved among G protein-coupled receptors (GPCR-s), and its function has not been examined yet in human glycoprotein hormone receptors (GPHR-s). Our results indicate that the N4321.50D mutation disrupts important, architecture-stabilizing intramolecular interactions, and ultimately lead to the complete intracellular retention of the receptor. On the other hand P4492.39 is located in the intracellular part of the receptor which is important in G protein coupling. The P4492.39L mutation results in signaling impairment, with a more profound effect on the Gq/11 pathway. Conclusion TSHR mutations are common among Hungarian patients with CH. The novel genetic alterations revealed important structural role of the N4321.50 and the P4492.39 residues in receptor expression and signaling, respectively.

Molecular radiotherapy (MRT) is an effective technique for the treatment of several oncological diseases, based on the delivery of radiation to malignant tissues via the interaction of an agent with molecular sites and receptors [1] . In the clinical practice, the calculation of the absorbed dose is performed using the Medical Internal Radiation Dose (MIRD) scheme, based on pre-calculated transfer functions determined on standard anthropomorphic phantoms. The MIRD scheme assumes that radiopharmaceutical activity is distributed uniformly inside the organs [2] . For this reason, dose calculation is not planned or optimised for patients’ specific characteristics. To increase the efficacy and quality of clinical trials, a detailed and reliable 3D patient specific dosimetry is required. Monte Carlo techniques are shown to provide the most accurate approach for the radiotherapy dose calculation. In this work, we used Raydose Monte Carlo code [3] to provide a patient specific 3D dose distribution in MRT at the voxel level for patients enrolled as part of a clinical trial on Peptide Receptor Radiotherapy (PRRT) with 177Lu and we compared doses to lesions and OARs with standard dose calculations obtained using the MIRD method. One hundred patients were enrolled in a clinical trial in PRRT with an activity prescription of 177Lu-DOTA-Tyr3-octreotide. All patients were scanned five times with a SPECT/CT scanner and both lesions and OARs were drawn manually on fused images. Sequential scans were co-registered using a non-rigid registration algorithm. Raydose 3D dose maps were compared with dose calculations obtained using the OLINDA/EXM software. Preliminary results for the first 20 patients show that mean doses calculated with OLINDA/EXM are significantly higher than mean doses calculated with Raydose. Initial data based on Monte Carlo dose calculations suggest a possible underestimation of the dose to OARs in PRRT treatments. More accurate dose calculation could be used on a patient by patient basis to increase the prescribed activity, maintaining a safe level of toxicity. A complete analysis that includes doses to lesions is in progress.

Cyclic AMP (cAMP) inhibits the proliferation of several tumor cells. We previously reported an antiproliferative effect of PKA I-selective cAMP analogs (8-PIP-cAMP and 8-HA-cAMP) on two human cancer cell lines of different origin. 8-Cl-cAMP, another cAMP analog with known antiproliferative properties, has been investigated as a potential anticancer drug. Here, we compared the antiproliferative effect of 8-Cl-cAMP and the PKA I-selective cAMP analogs in three human cancer cell lines (ARO, NPA and WRO). 8-Cl-cAMP and the PKA I-selective cAMP analogs had similarly potent antiproliferative effects on the BRAF-positive ARO and NPA cells, but not on the BRAF-negative WRO cells, in which only 8-Cl-cAMP consistently inhibited cell growth. While treatment with the PKA I-selective cAMP analogs was associated with growth arrest, 8-Cl-cAMP induced apoptosis. To further investigate the actions of 8-Cl-cAMP and the PKA I-selective cAMP analogs, we analyzed their effects on signaling pathways involved in cell proliferation and apoptosis. Interestingly, the PKA I-selective cAMP analogs, but not 8-Cl-cAMP, inhibited ERK phosphorylation, whereas 8-Cl-cAMP alone induced a progressive phosphorylation of the p38 mitogen-activated protein kinase (MAPK), via activation of AMPK by its metabolite 8-Cl-adenosine. Importantly, the pro-apoptotic effect of 8-Cl-cAMP could be largely prevented by pharmacological inhibition of the p38 MAPK. Altogether, these data suggest that 8-Cl-cAMP and the PKA I-selective cAMP analogs, though of comparable antiproliferative potency, act through different mechanisms. PKA I-selective cAMP analogs induce growth arrest in cells carrying the BRAF oncogene, whereas 8-Cl-cAMP induce apoptosis, apparently through activation of the p38 MAPK pathway.