TY - JOUR A1 - Graf, Nicolas A1 - Li, Zhoulei A1 - Herrmann, Ken A1 - Weh, Daniel A1 - Aichler, Michaela A1 - Slawska, Jolanta A1 - Walch, Axel A1 - Peschel, Christian A1 - Schwaiger, Markus A1 - Buck, Andreas K. A1 - Dechow, Tobias A1 - Keller, Ulrich T1 - Positron emission tomographic monitoring of dual phosphatidylinositol-3-kinase and mTOR inhibition in anaplastic large cell lymphoma JF - Oncotargets and Therapy N2 - Background: Dual phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibition offers an attractive therapeutic strategy in anaplastic large cell lymphoma depending on oncogenic nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) signaling. We tested the efficacy of a novel dual PI3K/mTOR inhibitor, NVP-BGT226 (BGT226), in two anaplastic large cell lymphoma cell lines in vitro and in vivo and performed an early response evaluation with positron emission tomography (PET) imaging using the standard tracer, 2-deoxy-2-[F-18] fluoro-D-glucose (FDG) and the thymidine analog, 3'-deoxy-3'-[F-18] fluorothymidine (FLT). Methods: The biological effects of BGT226 were determined in vitro in the NPM-ALK positive cell lines SU-DHL-1 and Karpas299 by 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, propidium iodide staining, and biochemical analysis of PI3K and mTOR downstream signaling. FDG-PET and FLT-PET were performed in immunodeficient mice bearing either SU-DHL-1 or Karpas299 xenografts at baseline and 7 days after initiation of treatment with BGT226. Lymphomas were removed for immunohistochemical analysis of proliferation and apoptosis to correlate PET findings with in vivo treatment effects. Results: SU-DHL-1 cells showed sensitivity to BGT226 in vitro, with cell cycle arrest in G0/G1 phase and an IC50 in the low nanomolar range, in contrast with Karpas299 cells, which were mainly resistant to BGT226. In vivo, both FDG-PET and FLT-PET discriminated sensitive from resistant lymphoma, as indicated by a significant reduction of tumor-to-background ratios on day 7 in treated SU-DHL-1 lymphoma-bearing animals compared with the control group, but not in animals with Karpas299 xenografts. Imaging results correlated with a marked decrease in the proliferation marker Ki67, and a slight increase in the apoptotic marker, cleaved caspase 3, as revealed by immunostaining of explanted lymphoma tissue. Conclusion: Dual PI3K/mTOR inhibition using BGT226 is effective in ALK-positive anaplastic large cell lymphoma and can be monitored with both FDG-PET and FLT-PET early on in the course of therapy. KW - mammalian target of rapamycin KW - phosphatidylinositol-3-kinase KW - lymphoma KW - early response KW - NVP-BGT226 KW - non-hodgkins-lymphoma KW - signaling pathway KW - FDG-PET KW - in-vivo KW - target KW - tumor KW - imaging proliferation KW - inhibition KW - positron emission tomography Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117915 VL - 7 ER - TY - JOUR A1 - Lapa, Constantin A1 - Werner, Rudolf A. A1 - Bluemel, Christina A1 - Lueckerath, Katharina A1 - Muegge, Dirk O. A1 - Strate, Alexander A1 - Haenscheid, Heribert A1 - Schirbel, Andreas A1 - Allen-Auerbach, Martin S. A1 - Bundschuh, Ralph A. A1 - Buck, Andreas K. A1 - Herrmann, Ken T1 - Prediction of clinically relevant hyperkalemia in patients treated with peptide receptor radionuclide therapy JF - EJNMMI Research N2 - Background Peptide receptor radionuclide therapy (PRRT) is applied in patients with advanced neuroendocrine tumors. Co-infused amino acids (AA) should prevent nephrotoxicity. The aims of this study were to correlate the incidence of AA-induced hyperkalemia (HK) (≥5.0 mmol/l) and to identify predictors of AA-induced severe HK (>6.0). Methods In 38 patients, standard activity of \(^{177}Lu\)-labelled somatostatin analogs was administered. Pre-therapeutic kidney function was assessed by renal scintigraphy and laboratory tests. For kidney protection, AA was co-infused. Biochemical parameters (potassium, glomerular filtration rate, creatinine, blood urea nitrogen (BUN), sodium, phosphate, chloride, and lactate dehydrogenase (LDH)) were obtained prior to 4 and 24 h after the AA infusion. Incidence of HK (≥5.0) was correlated with pre-therapeutic kidney function and serum parameters. Formulas for the prediction of severe hyperkalemia (>6.0) were computed and prospectively validated. Results At 4 h, HK (≥5.0) was present in 94.7% with severe HK (>6.0) in 36.1%. Values normalized after 24 h in 84.2%. Pre-therapeutic kidney function did not correlate with the incidence of severe HK. Increases in K+ were significantly correlated with decreases in phosphate (r = −0.444, p < 0.005) and increases in BUN (r = 0.313, p = 0.056). A baseline BUN of >28 mg/dl had a sensitivity of 84.6% and a specificity of 60.0% (AUC = 0.75) in predicting severe HK of >6.0 (phosphate, AUC = 0.37). Computing of five standard serum parameters (potassium, BUN, sodium, phosphate, LDH) resulted in a sensitivity of 88.9% and a specificity of 79.3% for the prediction of severe HK >6.0 (accuracy = 81.6%). Conclusions A combination of serum parameters predicted prospectively the occurrence of relevant HK with an accuracy of 81.6% underlining its potential utility for identifying ‘high-risk’ patients prone to PRRT. KW - amino acids KW - kidney function KW - hyperkalemia KW - PRRT KW - NET KW - MAG3 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124963 VL - 4 IS - 74 ER - TY - JOUR A1 - Chen, Xinyu A1 - Werner, Rudolf A. A1 - Javadi, Mehrbod S. A1 - Maya, Yoshifumi A1 - Decker, Michael A1 - Lapa, Constantin A1 - Herrmann, Ken A1 - Higuchi, Takahiro T1 - Radionuclide imaging of neurohormonal system of the heart JF - Theranostics N2 - Heart failure is one of the growing causes of death especially in developed countries due to longer life expectancy. Although many pharmacological and instrumental therapeutic approaches have been introduced for prevention and treatment of heart failure, there are still limitations and challenges. Nuclear cardiology has experienced rapid growth in the last few decades, in particular the application of single photon emission computed tomography (SPECT) and positron emission tomography (PET), which allow non-invasive functional assessment of cardiac condition including neurohormonal systems involved in heart failure; its application has dramatically improved the capacity for fundamental research and clinical diagnosis. In this article, we review the current status of applying radionuclide technology in non-invasive imaging of neurohormonal system in the heart, especially focusing on the tracers that are currently available. A short discussion about disadvantages and perspectives is also included. KW - SPECT KW - radiotracer KW - heart failure KW - cardiac neurohormonal system KW - nuclear cardiology KW - PET Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149205 VL - 5 IS - 6 ER - TY - JOUR A1 - Lapa, Constantin A1 - Kircher, Stefan A1 - Schirbel, Andreas A1 - Rosenwald, Andreas A1 - Kropf, Saskia A1 - Pelzer, Theo A1 - Walles, Thorsten A1 - Buck, Andreas K. A1 - Weber, Wolfgang A. A1 - Wester, Hans-Juergen A1 - Herrmann, Ken A1 - Lückerath, Katharina T1 - Targeting CXCR4 with [\(^{68}\)Ga]Pentixafor: a suitable theranostic approach in pleural mesothelioma? JF - Oncotarget N2 - C-X-C motif chemokine receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer. This study investigated the feasibility of CXCR4-directed imaging with positron emission tomography/computed tomography (PET/CT) using [\(^{68}\)Ga]Pentixafor in malignant pleural mesothelioma. Six patients with pleural mesothelioma underwent [\(^{68}\)Ga]Pentixafor-PET/CT. 2′-[\(^{18}\)F]fluoro-2′-deoxy-D-glucose ([\(^{18}\)F]FDG)-PET/CT (4/6 patients) and immunohistochemistry obtained from biopsy or surgery (all) served as standards of reference. Additionally, 9 surgical mesothelioma samples were available for histological work-up. Whereas [\(^{18}\)F]FDG-PET depicted active lesions in all patients, [\(^{68}\)Ga]Pentixafor-PET/CT recorded physiologic tracer distribution and none of the 6 patients presented [\(^{68}\)Ga]Pentixafor-positive lesions. This finding paralleled results of immunohistochemistry which also could not identify relevant CXCR4 surface expression in the samples analyzed. In contrast to past reports, our data suggest widely absence of CXCR4 expression in pleural mesothelioma. Hence, robust cell surface expression should be confirmed prior to targeting this chemokine receptor for diagnosis and/or therapy. KW - PET KW - CXCR4 KW - [\(^{68}\)Ga] pentixafor KW - pleural mesothelioma KW - theranostics Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-169989 VL - 8 IS - 57 ER - TY - JOUR A1 - Werner, Rudolf A. A1 - Beykan, Seval A1 - Higuchi, Takahiro A1 - Lückerath, Katharina A1 - Weich, Alexander A1 - Scheurlen, Michael A1 - Bluemel, Christina A1 - Herrmann, Ken A1 - Buck, Andreas K. A1 - Lassmann, Michael A1 - Lapa, Constantin A1 - Hänscheid, Heribert T1 - The impact of \(^{177}\)Lu-octreotide therapy on \(^{99m}\)Tc-MAG3 clearance is not predictive for late nephropathy JF - Oncotarget N2 - Peptide Receptor Radionuclide Therapy (PRRT) for the treatment of neuroendocrine tumors may lead to kidney deterioration. This study aimed to evaluate the suitability of \(^{99m}\)Tc-mercaptoacetyltriglycine (\(^{99m}\)Tc-MAG3) clearance for the early detection of PRRT-induced changes on tubular extraction (TE). TE rate (TER) was measured prior to 128 PRRT cycles (7.6±0.4 GBq \(^{177}\)Lu-octreotate/octreotide each) in 32 patients. TER reduction during PRRT was corrected for age-related decrease and analyzed for the potential to predict loss of glomerular filtration (GF). The GF rate (GFR) as measure for renal function was derived from serum creatinine. The mean TER was 234 ± 53 ml/min/1.73 m² before PRRT (baseline) and 221 ± 45 ml/min/1.73 m² after a median follow-up of 370 days. The age-corrected decrease (mean: -3%, range: -27% to +19%) did not reach significance (p=0.09) but significantly correlated with the baseline TER (Spearman p=-0.62, p<0.001). Patients with low baseline TER showed an improved TER after PRRT, high decreases were only observed in individuals with high baseline TER. Pre-therapeutic TER data were inferior to plasma creatinine-derived GFR estimates in predicting late nephropathy. TER assessed by \(^{99m}\)Tc-MAG3­clearance prior to and during PRRT is not suitable as early predictor of renal injury and an increased risk for late nephropathy. KW - renal scintigraphy KW - neuroendocrine tumor KW - 177Lu KW - MAG3 KW - PRRT Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177318 VL - 7 IS - 27 ER - TY - JOUR A1 - Weich, Alexander A1 - Higuchi, Takahiro A1 - Bundschuh, Ralph A. A1 - Lapa, Constantin A1 - Serfling, Sebastian E. A1 - Rowe, Steven P. A1 - Pomper, Martin G. A1 - Herrmann, Ken A1 - Buck, Andreas K. A1 - Derlin, Thorsten A1 - Werner, Rudolf A. T1 - Training on reporting and data system (RADS) for somatostatin-receptor targeted molecular imaging can reduce the test anxiety of inexperienced readers JF - Molecular Imaging and Biology N2 - Purpose For somatostatin receptor (SSTR)-positron emission tomography/computed tomography (PET/CT), a standardized framework termed SSTR-reporting and data system (RADS) has been proposed. We aimed to elucidate the impact of a RADS-focused training on reader’s anxiety to report on SSTR-PET/CT, the motivational beliefs in learning such a system, whether it increases reader’s confidence, and its implementation in clinical routine. Procedures A 3-day training course focusing on SSTR-RADS was conducted. Self-report questionnaires were handed out prior to the course (Pre) and thereafter (Post). The impact of the training on the following categories was evaluated: (1) test anxiety to report on SSTR-PET/CT, (2) motivational beliefs, (3) increase in reader’s confidence, and (4) clinical implementation. To assess the effect size of the course, Cohen’s d was calculated (small, d = 0.20; large effect, d = 0.80). Results Of 22 participants, Pre and Post were returned by 21/22 (95.5%). In total, 14/21 (66.7%) were considered inexperienced (IR, < 1 year experience in reading SSTR-PET/CTs) and 7/21 (33.3%) as experienced readers (ER, > 1 year). Applying SSTR-RADS, a large decrease in anxiety to report on SSTR-PET/CT was noted for IR (d =  − 0.74, P = 0.02), but not for ER (d = 0.11, P = 0.78). For the other three categories motivational beliefs, reader’s confidence, and clinical implementation, agreement rates were already high prior to the training and persisted throughout the course (P ≥ 0.21). Conclusions A framework-focused reader training can reduce anxiety to report on SSTR-PET/CTs, in particular for inexperienced readers. This may allow for a more widespread adoption of this system, e.g., in multicenter trials for better intra- and interindividual comparison of scan results. KW - PET/CT KW - neuroendocrine tumor KW - PRRT KW - peptide receptor radionuclide therapy KW - reporting and data system KW - SSTR-RADS KW - RADS Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324645 VL - 24 IS - 4 ER - TY - JOUR A1 - Lapa, Constantin A1 - Linsenmann, Thomas A1 - Lückerath, Katharina A1 - Samnick, Samuel A1 - Herrmann, Ken A1 - Stoffer, Carolin A1 - Ernestus, Ralf-Ingo A1 - Buck, Andreas K. A1 - Löhr, Mario A1 - Monoranu, Camelia-Maria T1 - Tumor-Associated Macrophages in Glioblastoma Multiforme—A Suitable Target for Somatostatin Receptor-Based Imaging and Therapy? JF - PLoS One N2 - Background Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. Tumor-associated macrophages (TAM) have been shown to promote malignant growth and to correlate with poor prognosis. [1,4,7,10-tetraazacyclododecane-NN′,N″,N′″-tetraacetic acid]-d-Phe1,Tyr3-octreotate (DOTATATE) labeled with Gallium-68 selectively binds to somatostatin receptor 2A (SSTR2A) which is specifically expressed and up-regulated in activated macrophages. On the other hand, the role of SSTR2A expression on the cell surface of glioma cells has not been fully elucidated yet. The aim of this study was to non-invasively assess SSTR2A expression of both glioma cells as well as macrophages in GBM. Methods 15 samples of patient-derived GBM were stained immunohistochemically for macrophage infiltration (CD68), proliferative activity (Ki67) as well as expression of SSTR2A. Anti-CD45 staining was performed to distinguish between resident microglia and tumor-infiltrating macrophages. In a subcohort, positron emission tomography (PET) imaging using \(^{68}Ga-DOTATATE\) was performed and the semiquantitatively evaluated tracer uptake was compared to the results of immunohistochemistry. Results The amount of microglia/macrophages ranged from <10% to >50% in the tumor samples with the vast majority being resident microglial cells. A strong SSTR2A immunostaining was observed in endothelial cells of proliferating vessels, in neurons and neuropile. Only faint immunostaining was identified on isolated microglial and tumor cells. Somatostatin receptor imaging revealed areas of increased tracer accumulation in every patient. However, retention of the tracer did not correlate with immunohistochemical staining patterns. Conclusion SSTR2A seems not to be overexpressed in GBM samples tested, neither on the cell surface of resident microglia or infiltrating macrophages, nor on the surface of tumor cells. These data suggest that somatostatin receptor directed imaging and treatment strategies are less promising in GBM. KW - glioma KW - positron emission tomography KW - glioblastoma multiforme KW - macrophages KW - somatostatin KW - microglial cells KW - immunostaining KW - magnetic resonance imaging Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125498 VL - 10 IS - 3 ER - TY - JOUR A1 - Herrmann, Ken A1 - Buck, Andreas K. A1 - Schuster, Tibor A1 - Abbrederis, Kathrin A1 - Blümel, Christina A1 - Santi, Ivan A1 - Rudelius, Martina A1 - Wester, Hans-Jürgen A1 - Peschel, Christian A1 - Schwaiger, Markus A1 - Dechow, Tobias A1 - Keller, Ulrich T1 - Week one FLT-PET response predicts complete remission to R-CHOP and survival in DLBCL JF - Oncotarget N2 - Despite improved survival in the Rituximab (R) era, a considerable number of patients with diffuse large B-cell lymphoma (DLBCL) ultimately die from the disease. Functional imaging using [18F]fluorodeoxyglucose-PET is suggested for assessment of residual viable tumor very early during treatment but is compromised by non-specific tracer retention in inflammatory lesions. The PET tracer [18F]fluorodeoxythymidine (FLT) as surrogate marker of tumor proliferation may overcome this limitation. We present results of a prospective clinical study testing FLT-PET as superior and early predictor of response to chemotherapy and outcome in DLBCL. 54 patients underwent FLT-PET prior to and one week after the start of R-CHOP chemotherapy. Repetitive FLT-PET imaging was readily implemented into the diagnostic work-up. Our data demonstrate that the reduction of FLT standard uptake valuemean (SUVmean) and SUVmax one week after chemotherapy was significantly higher in patients achieving complete response (CR, n=48; non-CR, n=6; p<0.006). Martingale-residual and Cox proportional hazard analyses showed a significant monotonous decrease of mortality risk with increasing change in SUV. Consistent with these results, early FLT-PET response showed relevant discriminative ability in predicting CR. In conclusion, very early FLT-PET in the course of R-CHOP chemotherapy is feasible and enables identification of patients at risk for treatment failure. KW - [18F]Fluorodeoxythymidine KW - FLT-PET KW - positron emission tomography KW - DLBCL KW - lymphoma Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120659 SN - 1949-2553 VL - 5 IS - 12 ER - TY - JOUR A1 - Lapa, Constantin A1 - Arias-Loza, Paula A1 - Hayakawa, Nobuyuki A1 - Wakabayashi, Hiroshi A1 - Werner, Rudolf A. A1 - Chen, Xinyu A1 - Shinaji, Tetsuya A1 - Herrmann, Ken A1 - Pelzer, Theo A1 - Higuchi, Takahiro T1 - Whitening and impaired glucose utilization of brown adipose tissue in a rat model of type 2 diabetes mellitus JF - Scientific Reports N2 - Brown adipose tissue (BAT) is an attractive therapeutic target to combat diabetes and obesity due to its ability to increase glucose expenditure. In a genetic rat model (ZDF fa/fa) of type-2 diabetes and obesity, we aimed to investigate glucose utilization of BAT by \(^{18}\)F-FDG PET imaging. Male Zucker diabetic fatty (ZDF) and Male Zucker lean (ZL) control rats were studied at 13 weeks. Three weeks prior to imaging, ZDF rats were randomized into a no-restriction (ZDF-ND) and a mild calorie restriction (ZDF-CR) group. Dynamic \(^{18}\)F-FDG PET using a dedicated small animal PET system was performed under hyperinsulinemic-euglycemic clamp. \(^{18}\)F-FDG PET identified intense inter-scapular BAT glucose uptake in all ZL control rats, while no focally increased \(^{18}\)F-FDG uptake was detected in all ZDF-ND rats. Mild but significant improved BAT tracer uptake was identified after calorie restriction in diabetic rats (ZDF-CR). The weight of BAT tissue and fat deposits were significantly increased in ZDF-CR and ZDF-ND rats as compared to ZL controls, while UCP-1 and mitochondrial concentrations were significantly decreased. Whitening and severely impaired insulin-stimulated glucose uptake in BAT was confirmed in a rat model of type-2 diabetes. Additionally, calorie restriction partially restored the impaired BAT glucose uptake. KW - molecular medicine KW - endocrinology Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159066 VL - 7 ER -