Neuroendocrine Tumor Disease Research Articles

Clinical Validation of a Pixon-Based Reconstruction Method Allowing a Twofold Reduction in Planar Images Time of 111In-Pentetreotide Somatostatin Receptor Scintigraphy.

The objective of this study was to evaluate the diagnostic efficacy of Pixon-based reconstruction method on planar somatostatin receptor scintigraphy (SRS). All patients with neuroendocrine tumors (NETs) disease who were referred for SRS to our department during 1-year period from January to December 2015 were consecutively included. Three nuclear physicians independently reviewed all the data sets of images which included conventional images (CI; 15 min/view) and processed images (PI) obtained by reconstructing the first 450 s extracted data using Oncoflash® software package. Image analysis using a 3-point rating scale for abnormal uptake of 111 Indium-DTPA-Phe-octreotide in any lesion or organ was interpreted as positive, uncertain, or negative for the evidence of NET disease. A maximum grade uptake of the radiotracer in the lesion was assessed by the Krenning scale method. The results of image interpretation by the two methods were considered significantly discordant when the difference in organ involvement assessment was negative vs. positive or in lesion uptake was ≥2 grades. Agreement between the results of two methods and by different scan observers was evaluated using Cohen κ coefficients. There was no significant (p = 0.403) correlation between data acquisition protocol and quality image. The rates of significant discrepancies for exam interpretation and organs involvement assessment were 2.8 and 2.6%, respectively. Mean κ values revealed a good agreement for concordance between CI and PI interpretation without difference of agreement for inter/intra-observer analysis. Our results suggest the feasibility to use a Pixon-based reconstruction method for SRS planar images allowing a twofold reduction of acquisition time and without significant alteration of image quality or on image interpretation.

Lu-177 DOTATATE dosimetry for neuroendocrine tumor: single center experience

Lu-177 labelled with DOTATE is widely acceptable to treat Neuroendocrine Tumor (NET) disease and it better improvement of quality of patients’ life since few years ago. However, the radionuclide toxicity becomes the main limitation of the (NET) treatment. Therefore, we performed a pilot study aimed to estimate radiation absorbed doses to dose-limiting organs to develop a systemic therapy with Lu-177 in NET patients. In this study, five set of planar whole body images was acquired every 0.5 hour, 4 hours, 24 hours, 48 hours and 72 hours after Lu-177 administrations. The planar image acquisition was done using Philip Brightview X with Medium Energy General Purpose Collimator (MEGP) collimator. All patients’ images in Conjugate View (CV) format were transferred into PMOD 3.7 Software for Region of Interest (ROI) analysis. The ROI were drawn at selected organs such as kidneys, liver, spleen and bladder. This study found that the mean absorbed dose for kidneys 0.62 ± 0.26 Gy/GBq, liver 0.63 ± 0.28 Gy/GBq, spleen 0.83 ± 0.73 Gy/GBq and bladder 0.14 ± 0.07 Gy/GBq. The radionuclide kinetic for the whole body 99.7 ± 0.1 percent at 0.5 hours, 79.5 ± 10.7 percent at 4 hours, 56.6 ± 10.3 percent at 24 hours, 43.2 ± 7.9 percent at 48 hours and 37.1 ± 9.0 percent at 72 hours. This study verifies that this planar quantitative method able to determine organ at risk and the result line with other published data.

A Delphic consensus assessment: imaging and biomarkers in gastroenteropancreatic neuroendocrine tumor disease management.

The complexity of the clinical management of neuroendocrine neoplasia (NEN) is exacerbated by limitations in imaging modalities and a paucity of clinically useful biomarkers. Limitations in currently available imaging modalities reflect difficulties in measuring an intrinsically indolent disease, resolution inadequacies and inter-/intra-facility device variability and that RECIST (Response Evaluation Criteria in Solid Tumors) criteria are not optimal for NEN. Limitations of currently used biomarkers are that they are secretory biomarkers (chromogranin A, serotonin, neuron-specific enolase and pancreastatin); monoanalyte measurements; and lack sensitivity, specificity and predictive capacity. None of them meet the NIH metrics for clinical usage. A multinational, multidisciplinary Delphi consensus meeting of NEN experts (n = 33) assessed current imaging strategies and biomarkers in NEN management. Consensus (>75%) was achieved for 78% of the 142 questions. The panel concluded that morphological imaging has a diagnostic value. However, both imaging and current single-analyte biomarkers exhibit substantial limitations in measuring the disease status and predicting the therapeutic efficacy. RECIST remains suboptimal as a metric. A critical unmet need is the development of a clinico-biological tool to provide enhanced information regarding precise disease status and treatment response. The group considered that circulating RNA was better than current general NEN biomarkers and preliminary clinical data were considered promising. It was resolved that circulating multianalyte mRNA (NETest) had clinical utility in both diagnosis and monitoring disease status and therapeutic efficacy. Overall, it was concluded that a combination of tumor spatial and functional imaging with circulating transcripts (mRNA) would represent the future strategy for real-time monitoring of disease progress and therapeutic efficacy.

Evaluation of the concordance between the stage of the disease and Ki-67 proliferation index in gastroenteropancreatic neuroendocrine tumors

This study aimed to determine the degree of concordance between TNM staging used in the determination of the prognosis of gastroenteropancreatic neuroendocrine tumor (GEP-NET) patients and the Ki-67 proliferation index value used in the grading of these tumors and investigate the most reliable prognostic parameter among them. The medical files of the patients with GEP-NET who were diagnosed or followed up in Erciyes University Faculty of Medicine were retrospectively examined and demographic characteristics, survival times, grade of these tumors, histopathologically detected Ki-67 values, and histopathological characteristics were recorded and evaluated statistically. The mean age (53.09±14.6 years; range, 16-85 years) of all (n=141) the patients was estimated. The patient population included 72 (51.1%) female and 69 (48.9%) male patients, with a male/female ratio of 0.95. The most frequently encountered primary sites were the stomach (33.3%), and then in decreasing oder of frequency the pancreas (27%), colon-rectum (15.6%), the small intestine (12.8%), and the appendix (11.3%). The GEP-NET of the patients was in grade 1 (G1) (n: 103; 73%), grade 2 (G2) (n: 24; 17%), and grade 3 (G3) (n: 14; 10%). The GEP-NET of the patients was stage I (n: 66; 46.8%), stage II (n: 14; 9.9%), stage III (n: 12; 8.5%), and stage IV (n: 49; 34.8%). In the statistical analysis, Ki-67 increased in parallel with the stage of the disease (P<0.001). As Ki-67 increased at a rate of 1%, survival rates of the patients decreased 1.027 times (P=0.01). Five-year survival rates of the patients were 88% in G1, 44% in G2, and 24% in G3. Patients in G2 and G3 had a 6.67 and 12.38 times lower chance of survival compared with G1 patients, respectively. Survival rates of stage IV patients were 5.6 times lower relative to stages I and II patients, respectively (P<0.001). The median 5-year survival rates of the patients were 90% in stage I, 100% in stage II, 47% in stage III, and 46% in stage IV. In univariate analysis, age of the patients, grade, stage of the tumor, and lymph node metastases were found to be parameters that affected overall survival, whereas no significant correlation was found between the sex of the patient and the primary organ from which the tumor originated and survival rates. However, in the multivariate analysis, survival rates decreased inversely with age, whereas no significant correlation was found between grade and stage of the tumor and survival rates. In conclusion, a decrease in the average survival rate in parallel with an increase in the grade of the tumor was more prominent compared with a decrease in survival rates in accordance with an increase in the stage of the tumor. This indicates that in the prediction of prognosis in patients with GEP-NET, the Ki-67 value can be a more important evaluation factor relative to staging.

Dual inhibition of PI3K and mTORC1/C2 by PKI-587 (PF-05212384) as a promising therapeutic option for pulmonary neuroendocrine tumor disease

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Gene transcript analysis blood values correlate with ⁶⁸Ga-DOTA-somatostatin analog (SSA) PET/CT imaging in neuroendocrine tumors and can define disease status.

Precise determination of neuroendocrine tumor (NET) disease status and response to therapy remains a rate-limiting concern for disease management. This reflects limitations in biomarker specificity and resolution capacity of imaging. In order to evaluate biomarker precision and identify if combinatorial blood molecular markers and imaging could provide added diagnostic value, we assessed the concordance between (68)Ga-somatostatin analog (SSA) positron emission tomography (PET), circulating NET gene transcripts (NETest), chromogranin A (CgA), and Ki-67 in NETs. We utilized two independent patient groups with positive (68)Ga-SSA PET: data set 1 ((68)Ga-SSA PETs undertaken for peptide receptor radionuclide therapy (PRRT), as primary or salvage treatment, n = 27) and data set 2 ((68)Ga-SSA PETs performed in patients referred for initial disease staging or restaging after various therapies, n = 22). We examined the maximum standardized uptake value (SUVmax), circulating gene transcripts, CgA levels, and baseline Ki-67. Regression analyses, generalized linear modeling, and receiver-operating characteristic (ROC) analyses were undertaken to determine the strength of the relationships. SUVmax measured in two centers were mathematically evaluated (regression modeling) and determined to be comparable. Of 49 patients, 47 (96 %) exhibited a positive NETest. Twenty-six (54 %) had elevated CgA (χ(2) = 20.1, p < 2.5×10(-6)). The majority (78 %) had Ki-67 < 20 %. Gene transcript scores were predictive of imaging with >95 % concordance and significantly correlated with SUVmax (R (2) = 0.31, root-mean-square error = 9.4). The genes MORF4L2 and somatostatin receptors SSTR1, 3, and 5 exhibited the highest correlation with SUVmax. Progressive disease was identified by elevated levels of a quotient of MORF4L2 expression and SUVmax [ROC-derived AUC (R (2) = 0.7, p < 0.05)]. No statistical relationship was identified between CgA and Ki-67 and no relationship with imaging parameters was evident. (68)Ga-SSA PET imaging parameters (SUVmax) correlated with a circulating NET transcript signature. Disease status could be predicted by an elevated quotient of gene expression (MORF4L2) and SUVmax. These observations provide the basis for further exploration of strategies that combine imaging parameters and disease-specific molecular data for the improvement of NET management.

Neuroendocrine gene transcript analysis of blood to define the completeness of surgical resection and identify stable or progressive neuroendocrine tumor disease.

293 Background: A critical requirement in NET management is a sensitive, specific, reproducible blood biomarker test. Surgery and somatostatin analogs (SSAs) are widely used but efficacy is difficult to determine. Imaging is relatively insensitive for residual/recurrent disease determination and symptoms remains the only way to determine SSA efficacy. We evaluated a PCR-based 51 transcript signature (NETest) comparing it to CgA to determine whether biomarkers were effective in defining surgical resection and SSA efficacy. Methods: GEP-NETs (n=50) [M:F 19:31; median age: 58 years, small intestine: n=35, pancreas n=9, rectum n=3, appendix: n=2, stomach n=1] were evaluated. Groups included surgery (n=15, R0-no disease), and SSA therapy (n=35). qRT-PCR was used for transcript measurement, ELISA (DAKO) for CgA and imaging (RECIST) for clinical status. NETest defined risk of disease activity (low disease activity risk &lt;47%, high risk 47-100%). Results: Resection decreased NETest (pre-surgery: 80±6%; 1 post-surgery: 29±6%, p&lt;0.0001). Thirteen (87%) were high risk before surgery; post-surgery two (13%) remained high risk (despite lowered score), 11 (74%) were low risk and 2 normal. Four (26%) developed recurrence at 6 months. CgA levels were non-informative. In the SSA group, the NETest was lower in clinically stable disease (32±3.7%; n=25) than in progressive disease (82±4.3%, n=10; p&lt;0.0001). All patients in the latter were categorized as high risk disease activity. The accuracy for differentiating stable from active disease was 92% (sensitivity=100%, specificity=88%). Three SSA patients developed clinically progressive disease with concordant increases in NETest. CgA levels were not significant and were non-informative. Conclusions: NET transcript analysis accurately defined surgical cytoreduction and identified biochemical evidence of residual disease. NETest also accurately identified stable and progressive clinical disease activity during SSA treatment. Blood-based multigene analytic measurement will facilitate early detection of residual/recurrent disease and further define therapeutic efficacy for surgery and SSAs.

Transplantation and Debulking Procedures for Neuroendocrine Tumors.

An array of treatment modalities is currently available in the management of patients with neuroendocrine tumors (NETs). Complete resection of the primary tumor and all metastatic lesions represents the only approach possessing intent to cure. However, due to patients' disease frequently being at an advanced stage on initial diagnosis only a minority of individuals are candidates for radical procedures. Cytoreductive surgery (debulking) may potentially confer improvements in quality of life and prolong overall survival. In light of the recent introduction of effective nonsurgical treatment options, the indication for cytoreductive surgery needs to be carefully assessed. The presence of nonresectable liver metastases is not a contraindication for resection of the primary tumor including locoregional disease in small bowel NETs. Resection of primary pancreatic NETs in the setting of unresectable metastatic liver disease may have a beneficial effect on the prognosis of selected patients with a tumor requiring less aggressive local surgery. Liver transplantation presents a generally accepted approach in meticulously selected patients with unresectable liver metastases. Stringent and validated selection criteria are not available. While overall survival is satisfactory, high recurrence rates hinder outcomes and call for the development and implementation of neoadjuvant and adjuvant concepts. Advances in intestinal transplantation over time may justify consideration of an individual with advanced neuroendocrine tumor disease unresponsive to standard medical or surgical treatment.

Therapeutic strategies for neuroendocrine liver metastases.

Patients who have neuroendocrine tumors frequently present with liver metastases. A wide panel of treatment options exists for these patients. Liver resection with curative intent achieves the best long-term results. Highly selected patients may be considered for liver transplantation. Substantial recurrence rates reported after surgical approaches call for neoadjuvant and adjuvant concepts. Liver-directed, locally ablative procedures are recommended for patients with limited, nonresectable tumor burden. Angiographic liver-directed techniques, such as transarterial embolization, transarterial chemoembolization, and selective internal radiotherapy, offer excellent palliation for patients with liver-predominant disease. Peptide receptor radionuclide therapy is a promising palliative procedure for patients with hepatic and/or extrahepatic metastases. The efficacy of these treatment options needs to be evaluated in randomized trials. Somatostatin analogues have demonstrated effectiveness not only for symptomatic relief in patients with secreting tumors but also for the control of proliferation in small intestinal neuroendocrine tumors and most recently also in those originating from the pancreas. Chemotherapy is an option mainly for those with pancreatic neuroendocrine tumors and high-grade tumors irrespective of the origin. Novel drugs targeting specific pathways within the tumor cell have produced improved progression-free survival compared with placebo in patients with pancreatic neuroendocrine tumors. Despite such a diverse armamentarium, there is uncertainty with regard to the optimal treatment regimens. Newly introduced molecular-based markers, along with the conduction of clinical trials comparing the efficacy of treatment modalities, offer a chance to move the treatment of neuroendocrine tumor disease toward personalized patient care. In this report, the authors review the approaches for treatment of neuroendocrine liver metastases, identify shortcomings, and anticipate future perspectives. Furthermore, clinical practice recommendations are provided for currently available treatment options. Although multiple modalities are available for the treatment of neuroendocrine liver metastases, optimal management is unclear. The current knowledge pertaining to these treatment options is analyzed.

A multitranscript blood neuroendocrine tumor molecular signature to identify treatment efficacy and disease progress.

4137 Background: Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) or NETs (also called “carcinoids”) are problematic since they present with advanced disease and have limited treatment options. Imaging has proved to be insensitive in identifying treatment effect. Similarly, the currently used biomarker, a neurosectory peptide, Chromogranin A (CgA) is of limited value as a predictor of treatment efficacy. We have developed a multi-transcript (n=51 genes) molecular signature for PCR-based blood analysis which exhibits a high sensitivity (85-98%), specificity (93-97%), positive predictive value (95-96%) and negative predictive value (87-98%) for the identification of GEP-NENs. This test significantly outperforms (p&lt;0005) plasma CgA (measured by ELISA). Methods: The candidate gene signature was examined by a 2-step PCR method in a training set of 130 blood samples (GEP-NENs: n=63, treatment-naïve (n=28)) and validated in an independent set ([n=182, GEP-NENs: n=133, including complete remission (n=4), clinically stable disease (n=82) and non-responders/clinically progressive disease (n=47). Results: The PCR score was significantly elevated (p&lt;0.0001) in the treatment-naïve group compared to treated GEP-NENs, while levels were significantly reduced (p&lt;0.004) in 11 matched samples (pre- and post-treatment – surgical removal (n=10), RFA (n=1)). In the independent set, the scores for complete remission were not different to controls (0.5±0.25 vs. 0.4±0.16), while scores for stable disease (0.63±0.12) were significantly lower than for non-responders (5.85±0.34, p&lt;0.002). Stable disease could be differentiated from clinically progressive disease since the latter exhibited a high score (85% vs. 10%, p&lt;0.0001). The performance metrics for differentiation were: sensitivity (91%), specificity (91%), PPV (86%), NPV (95%). Conclusions: This study demonstrated that the multi-transcript molecular signature is both sensitive and specific for the detection of neuroendocrine tumor disease and is capable of differentiating clinically stable from progressive disease. It therefore has potential utility as a measure for monitoring treatment efficacy for GEP-NENs.

Can the Standardized Uptake Values derived from Diagnostic 68Ga-DOTATATE PET/CT Imaging Predict the Radiation Dose delivered to the Metastatic Liver NET Lesions on 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy?

ABSTRACT Introduction Neuroendocrine neoplasms express somatostatin receptors, enabling the use of somatostatin analogs for molecular imaging, when labeled with the positron-emitter 68Ga for receptor positron emission tomography/computed tomography (PET/CT), and targeted radionuclide therapy, when labeled with beta-emitters, e.g. 90Y and 177Lu. Aim To investigate if 68Ga-DOTATATE PET-derived standardized uptake values (SUV) correlate with the dose delivered to the liver lesions following 177Lu-DOTATATE radionuclide therapy in patients with neuroendocrine neoplasms. Materials and methods Twelve adult (8M: 4F; mean age: 55.9 ± 14.5 years; range: 23-78 years) patients with documented neuroendocrine tumor (NET) disease and liver metastases were enrolled in the study. Ten patients were subjected to 68Ga-DOTATATE and one patient each underwent 68Ga-DOTATOC and 68Ga-DOTANOC diagnostic PET/CT imaging. Subsequently, on the basis of positive PET/CT scan findings for the metastatic NET disease, all these patients were subjected to peptide receptor radionuclide therapy (PRRNT) with 177Lu-DOTATATE. The reconstructed PET/CT data was used to calculate the SUVs on the identifiable liver lesions. The scintigraphic data acquired (anterior and posterior whole body images) following therapeutic doses of 177Lu-DOTATATE were subjected to the quantitative analysis (HERMES workstation and OLINDA/EXM software) to calculate the dose delivered to the hepatic lesions. Results The initial results of this preliminary study indicate poor correlation between SUV and the tumor dose and the linear regression analysis provided R2 values which explained only a small fraction of the total variance. Conclusion The SUVs derived from 68Ga-DOTA-peptide PET/CT images should be used with caution for the prediction of tumor dose on 177Lu-DOTA-peptide therapy as there are large intra- and interpatient variability. Further studies with large numbers of patients are warranted to establish such a correlation between SUV, tumor dose and the response assessment. How to cite this article Singh B, Prasad V, Schuchardt C, Kulkarni H, Baum RP. Can the Standardized Uptake Values derived from Diagnostic 68Ga-DOTATATE PET/CT Imaging Predict the Radiation Dose delivered to the Metastatic Liver NET Lesions on 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy? J Postgrad Med Edu Res 2013;47(1):7-13.

Neuroendocrine tumor disease: an evolving landscape

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) represent a heterogenous group of tumors arising from a variety of neuroendocrine cell types. The incidence and prevalence of GEP-NENs have markedly increased over the last three decades. Symptoms are often absent in early disease, or vague and nonspecific even in advanced disease. Delayed diagnosis is thus common. Chromogranin A is the most commonly used biomarker but has limitations as does the proliferative marker Ki-67%, which is often used for tumor grading and determination of therapy. The development of a multidimensional prognostic nomogram may be valuable in predicting tumor behavior and guiding therapy but requires validation. Identification of NENs that express somatostatin receptors (SSTR) allows for SSTR scintigraphy and positron emission tomography imaging using novel radiolabeled compounds. Complete surgical resection of limited disease or endoscopic ablation of small lesions localized in stomach or rectum can provide cure; however, the majority of GEP-NENs are metastatic (most frequently the liver and/or mesenteric lymph nodes) at diagnosis. Selected patients with metastatic disease may benefit from advanced surgical techniques including hepatic resection or liver transplantation. Somatostatin analogs are effective for symptomatic treatment and exhibit some degree of antiproliferative activity in small intestinal NENs. There is a place for streptozotocin, temozolomide, and capecitabine in the management of pancreatic NENs, while new agents targeting either mTOR (everolimus) or angiogenic (sunitinib) pathways have shown efficacy in these lesions.

The North American Neuroendocrine Tumor Society (NANETS) Guidelines

The North American Neuroendocrine Tumor Society (NANETS) had its initial organizational meeting in Portland, Oregon on September 28, 2006 to establish a professional society with the primary purpose to improve neuroendocrine tumor disease management through increased research and educational opportu

Neuroendocrine tumor disease state and PROMIS health-related quality of life scores.

6118 Background: Health-related quality of life (HRQL) can be disrupted in patients (pts) with malignancies. The objective of this study was to compare the HRQL burden of pts with neuroendocrine tumor (NET) in different disease states relative to the general population. Methods: Pts with NET were invited via email to participate in an online anonymous survey. The survey consisted of demographic and disease-related questions and two standardized measures of HRQL (RAND-36 and PROMIS-29). Scores for U.S. general population are normalized to 50. PROMIS scores were compared using analysis of variance among 3 groups: pts with no tumor currently present (e.g., surgically removed)—no current NET; pts with tumor that has not been surgically removed or has come back after surgery—current NET, but without carcinoid syndrome; current NET with carcinoid syndrome. Score differences of 2.5-5.0 points are generally regarded as clinically meaningful. Lower scores on the physical function and social role scales of the PROMIS indicate worse HRQL. Higher scores on other scales indicate worse HRQL. Results: A total of 663 pts participated and demonstrated worse HRQL scores compared to the general population on all subscale scores of the PROMIS-29 (all p<.01). Of these, 526 provided complete information on current NET and carcinoid syndrome. 443/526 (84%) pts had NET present, of these, 328/443 (74%) had carcinoid syndrome. Compared to pts with no current NET, pts with current NET had significantly worse HRQL scores and those with carcinoid syndrome reported the worst (Table, all p<0.01). Conclusions: Pts with current NET and carcinoid syndrome report worse HRQL compared to pts without carcinoid syndrome, which in turn report worse HRQL than those without current NET. Optimal management of NET and carcinoid syndrome may significantly improve HRQL among pts with NETs. Further analysis of treatment effect on HRQL is warranted. Mean PROMIS- 29 scores No current NET n = 83 Current NET, no carcinoid syndrome n = 115 Current NET + carcinoid syndrome n = 328 All n = 663 Physical function 52 47 43 45 Anxiety 51 53 55 54 Depression 48 50 53 52 Fatigue 48 52 57 55 Pain interference 46 50 54 52 Sleep Disturbance 48 49 54 52 Social role 53 48 45 46 Scores for U.S. general population normalized to 50. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Novartis Novartis Novartis Novartis

Compensatory activation of Akt in response to mTOR and Raf inhibitors – A rationale for dual-targeted therapy approaches in neuroendocrine tumor disease

Several studies have established a link between aberrant PI(3)K–Akt–mTOR- and Ras–Raf–MEK–Erk1/2 signaling and neuroendocrine tumor disease. In this study, we comparatively investigate the antitumor potential of novel small-molecule inhibitors targeting mTOR (RAD001), mTOR/PI(3)K (NVP-BEZ235) and Raf (Raf265) on human NET cell lines of heterogeneous origin. All inhibitors induced potent antitumor effects which involved the induction of apoptosis and G0/G1 arrest. However, the dual mTOR/PI(3)K inhibitor NVP-BEZ235 was more efficient compared to the single mTOR inhibitor RAD001. Consistently, NVP-BEZ235 prevented the negative feedback activation of Akt as observed after treatment with RAD001. Raf265 inhibited Erk1/2 phosphorylation but strongly induced Akt phosphorylation and VEGF secretion, suggesting the existence of a compensatory feedback loop on PI3K-Akt signaling. Finally, combined treatment with RAD001 or NVP-BEZ235 and Raf265 was more efficient than single treatment with either kinase inhibitor. Together, our data provide a rationale for dual targeting of PI(3)K–Akt–mTOR- and Ras–Raf–MEK–Erk1/2 signaling in NET disease.

Chromogranin A—Biological Function and Clinical Utility in Neuro Endocrine Tumor Disease

Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., chromogranin A (CgA) and amines. A critical issue is late diagnosis due to failure to identify symptoms or to establish the biochemical diagnosis. We review here the utility of CgA measurement in NETs and describe its biological role and the clinical value of its measurement. Literature review and analysis of the utility of plasma/serum CgA measurements in NETs and other diseases. CgA is a member of the chromogranin family; its transcription and peptide processing are well characterized, but its precise function remains unknown. Levels are detectable in the circulation but vary substantially (approximately 25%) depending on which assay is used. Serum and plasma measurements are concordant. CgA is elevated in approximately 90% of gut NETs and correlates with tumor burden and recurrence. Highest values are noted in ileal NETs and gastrointestinal NETs associated with multiple endocrine neoplasia type 1. Both functioning and nonfunctioning pancreatic NETs have elevated values. CgA is more frequently elevated in well-differentiated tumors compared to poorly differentiated NETs. Effective treatment is often associated with decrease in CgA levels. Proton pump inhibitors falsely increase CgA, but levels normalize with therapy cessation. CgA is currently the best available biomarker for the diagnosis of NETs. It is critical to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy. Measurement of plasma CgA is mandatory for the effective diagnosis and management of NET disease.

Unique susceptibility of a human lung carcinoid tumor cell line to infection with BK virus

Carcinoid syndrome is caused by the unregulated secretion of bioactive amines from neuroendocrine tumors arising primarily in the gastrointestinal tract and lungs. The incidence of carcinoid syndrome is 1–2/100,000 and the syndrome is thought to be increasing. Carcinoid tumors are relatively slow growing but can become highly metastatic. Currently, there is no effective therapy to inhibit cell proliferation or metastasis of neuroendocrine tumor (NET) disease. Polyomaviruses are a family of viruses that are able to transform cells and promote tumor formation. In this study, the polyomaviruses SV40, JCV, and BKV were used to assess the ability of polyomaviruses to productively infect a range of human carcinoid cell lines. Infection was assessed by the immunofluorescence detection of T antigen and V antigen. Viruses and cell lines that exhibited productive infections were subsequently assayed by FACS analysis for cell binding and dual promoter luciferase assay for early and late promoter activity. Most carcinoid cell lines were not susceptible to infection by polyomaviruses. However, BKV efficiently infected the pulmonary carcinoid H727 cell line but did not infect a control, non-carcinoid lung cell line (A549). BKV was found to bind to both the susceptible H727 cells and to the non-susceptible A549 cells but viral genes were only efficiently expressed in the H727 cell line. The data demonstrate that BKV can infect human pulmonary carcinoid cells. Infection does not seem to be solely mediated by the virus’ ability to bind to cells, as the virus will also bind to non-carcinoid control cells. Both early and late gene expression are supported by the pulmonary carcinoid cells.

Liver transplantation and pancreatic resection: A single-center experience and a review of the literature

Liver transplantation may occasionally be indicated in patients with unique clinical scenarios. Little is known regarding the outcomes of patients who have had a pancreatic resection prior to, in combination with, or after liver transplantation. A retrospective review of all patients undergoing liver transplantation from March 1998 to March 2008 identified 17 patients who also underwent pancreatic resection. An additional literature review was performed. Five underwent pancreatic resection prior to liver transplantation (1.7, 3.6, 3.8, 6.8, and 8.1 years), another 9 underwent pancreatic resection together with liver transplantation, and 3 underwent pancreatic resection after liver transplantation (2.2, 2.6, and 3.8 years). Indications for pancreatic resection included cholangiocarcinoma (n = 6), neuroendocrine tumor (n = 5), pancreatic cancer (n = 2), gastrointestinal stromal tumor (n = 1), periampullary adenocarcinoma (n = 1), duodenal adenomas (n = 1), and benign pancreatic mass (n = 1). Indications for liver transplantation were metastatic neuroendocrine tumor disease (n = 5), primary sclerosing cholangitis (n = 5), hepatitis C virus (n = 2), metastatic gastrointestinal stromal tumor (n = 1), Klatskin tumor (n = 1), alcohol cirrhosis (n = 1), alpha-1 antitrypsin deficiency (n = 1), and chemotherapy-induced cirrhosis (n = 1). One patient died intraoperatively, 7 patients died of tumor recurrence, 2 patients died from transplant complications, and 7 patients are still alive. Pancreatic resection-related complications included 4 pancreatic fistulas. A literature review confirmed liver transplantation/pancreatic resection-related complications. In conclusion, liver transplantation and pancreatic resection remain uncommon, and a good outcome can be achieved. Recurrence of malignant disease is the main factor limiting survival, and specific morbidity may be related to pancreatic resection and liver transplantation.

Aurora kinases as novel drug targets in gastroenteropancreatic neuroendocrine tumor disease: Antiproliferative and pro-apoptotic effects of ZM 447439, a new aurora kinase inhibitor, in BON and QGP-1 cells

22023 Background: The serine/threonine protein kinases aurora A and B, key regulators of mitosis, are emerging as novel drug targets for cancer treatment. Aurora B overexpression has been previously documented by immunohistochemistry in several types of human tumors. In gastroenteropancreatic neuroendocrine tumors (GEP-NETs) the therapeutic possibilities are still not satisfactory. Therefore, we assessed aurora B expression in a series of well-differentiated GEP-NETs and studied the effects of a novel aurora kinase A and B inhibitor (ZM 447439) in our well-differentiated human GEP-NET cell lines BON and QGP-1. Materials and Methods: Tumor specimens from 102 patients (40 foregut, 55 midgut, 7 hindgut) were studied immunohistochemically for aurora kinase expression. The cell lines BON and QGP-1 were treated with increasing concentrations of ZM 447439 (Tocris) with or without coincubation with Streptozocin, Doxorubicin, Octreotide and SOM-230. Growth inhibition was measured with crystal violet assays, apoptosis induction with caspase 3/7 activation and DNA fragmentation. Cell cycle analysis was evaluated by performing FACS analysis. Results: The immunohistochemical analysis of aurora B in our patient collective demonstrated an overexpression in a significant portion of tumors, compared with normal epithelium. Moreover, we demonstrate that ZM 447439 inhibited dose-dependently proliferation of BON and QGP-1 cells. Treatment with ZM 447439 induced apoptosis and dose-dependently led to a cell cycle arrest. In addition, combined treatment with the somatostatin analogues Octreotide and SOM-230 in BON cells and with Streptozocin and Doxorubicin in QGP-1 cells, ZM 447439 augmented significantly the antiproliferative effects of Octreotide, Streptozocin and Doxorubicin, but not in combination with SOM-230. Conclusion: Our results suggest that aurora B may represent a valid target in well differentiated GEP- NETs, since aurora B is overexpressed in these tumors, and aurora kinase inhibition by ZM 447439 seems to be a promising new therapeutic approach, which should be evaluated in further clinical trials. No significant financial relationships to disclose.

Inhibition of proliferation of small intestinal and bronchopulmonary neuroendocrine cell lines by using peptide analogs targeting receptors

Currently, no consistently effective therapy is available to inhibit cell proliferation or metastasis of neuroendocrine tumor (NET) disease. The effects of 4 novel peptides were analyzed: a targeted cytotoxic analog of luteinizing hormone-releasing hormone (LH-RH) analog (AN-152), a targeted cytotoxic analog of somatostatin (AN-238), and 2 antagonists of growth hormone-releasing hormone (GH-RH) on 3 NET (carcinoid) cell lines that expressed respective peptide receptors. The effects of the compounds were evaluated on cell proliferation in vitro using MTT uptake and Ki67 expression, apoptosis (caspase 3 expression and activity), and cell cycle parameters (DNA distribution). Proliferation of the LH-RH receptor-expressing lung NET, NCI-H720 line, was inhibited 2-fold by AN-152 containing doxorubicin compared with the chemotherapy alone (IC50 of 9.1 nM vs 24 nM). This was associated with a reduction in Ki67 transcript and an increase in both caspase 3 mRNA levels and activity. Proliferation of the GH-RH receptor expressing lung NET, NCI-H727 line, was inhibited by both GH-RH antagonists, the effects being mediated through changes in Ki67 expression, but not in caspase 3-mediated apoptosis. The small intestinal NET, KRJ-I line, was 8x more sensitive to inhibition by AN-238 than to 2-pyrolino-doxorubicin, reflected by increased caspase 3 transcript as well as activity. AN-238-mediated growth inhibition culminated in complete G1 arrest. The data demonstrate GH-RH antagonists or peptide-linked antineoplastic agents such as AN-152 and AN-238 are effective inhibitors of NET proliferation in vitro. Because peptide receptors such as those for GH-RH, LH-RH, and SST subtypes are commonly expressed by NETs, the development of antineoplastic agents targeted to specific tumor receptors may provide a more efficacious strategy than systemic chemotherapeutic agents currently in use.