Gastroenteropancreatic Neuroendocrine Tumors Research Articles

Exploring the Potential of High-Molar-Activity Samarium-153 for Targeted Radionuclide Therapy with [153Sm]Sm-DOTA-TATE.

Samarium-153 is a promising theranostic radionuclide, but low molar activities (Am) resulting from its current production route render it unsuitable for targeted radionuclide therapy (TRNT). Recent efforts combining neutron activation of 152Sm in the SCK CEN BR2 reactor with mass separation at CERN/MEDICIS yielded high-Am 153Sm. In this proof-of-concept study, we further evaluated the potential of high-Am 153Sm for TRNT by radiolabeling to DOTA-TATE, a well-established carrier molecule binding the somatostatin receptor 2 (SSTR2) that is highly expressed in gastroenteropancreatic neuroendocrine tumors. DOTA-TATE was labeled with 153Sm and remained stable up to 7 days in relevant media. The binding specificity and high internalization rate were validated on SSTR2-expressing CA20948 cells. In vitro biological evaluation showed that [153Sm]Sm-DOTA-TATE was able to reduce CA20948 cell viability and clonogenic potential in an activity-dependent manner. Biodistribution studies in healthy and CA20948 xenografted mice revealed that [153Sm]Sm-DOTA-TATE was rapidly cleared and profound tumor uptake and retention was observed whilst these were limited in normal tissues. This proof-of-concept study showed the potential of mass-separated 153Sm for TRNT and could open doors towards wider applications of mass separation in medical isotope production.

Diagnosis and management of gastroenteropancreatic neuroendocrine neoplasms by nuclear medicine: Update and future perspective.

Gastrointestinal (GI) cancers are the second most common cause of cancer related deaths in the World. Neuroendocrine neoplasms (NENs) is a rare tumor that originated from peptidergic neurons and neuroendocrine cells. NENs occurs in all parts of the body, especially in stomach, intestine, pancreas and lung. These rare tumors are challenging to diagnose at earlier stages because of their wide anatomical distribution and complex clinical features. Traditional imaging methods including magnetic resonance imaging (MRI) and computed tomography (CT) are mostly of useful for detection of larger primary tumors that are 1cm in size. A new medical imaging specialty called nuclear medicine uses radioactive substances for both diagnostic and therapeutic purposes. Nuclear medicine imaging relies on the tissue-specific uptake of radiolabeled tracers. Nuclear medicine techniques can easily identify the NENs tissues for their ability to absorb and concentrate amine, precursors, and peptides, whereas the traditional imaging methods are difficult to perform well. The somatostatin receptor (SSTR) is a targetable receptor frequently expressed in the gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), and is a promising target for tumor-targeted therapies and radiography. SSTR based somatostatin receptor imaging and peptide receptor radionuclide therapy (PRRT) has emerged as a new hot subject in the diagnosis and treatment of GEP-NENs due to the rapid development of somatostatin analogues (SSAs) and radionuclide. This review aims to provide an overview of the current status of nuclear medicine imaging modalities in the imaging of GEP-NENs, and puts them in perspective of clinical practice.

PREF-NET: a patient preference and experience study of lanreotide autogel administered in the home versus hospital setting among patients with gastroenteropancreatic neuroendocrine tumours in the UK

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

Outcomes in patients with advanced well-differentiated gastroenteropancreatic neuroendocrine tumours receiving PRRT early versus later

Outcomes in patients with advanced well-differentiated gastroenteropancreatic neuroendocrine tumours receiving PRRT early versus later

A relook at gastroenteropancreatic neuroendocrine tumours as per 2019 WHO classification-A tertiary centre experience.

Neuroendocrine neoplasm of GIT (gastrointestinal tract) and pancreas is heterogenous with variable clinical features and disease outcomes. Despite multiple attempts of risk stratification by grading and staging, some have unpredictable clinical courses. Well-differentiated grade 3 neuroendocrine tumour (G3NET) is a recent subcategory introduced in the 2019 WHO classification based on morphology, molecular profile and prognosis distinguishing it from neuroendocrine carcinoma(NEC). This study aimed at describing the spectrum of NENs encountered in a tertiary centre with focus on reclassifying previously reported G3 tumours into G3 NET and NEC and comparing the survival between them. This is an 8-year retrospective study of all gastro-entero-pancreatic neuroendocrine neoplasms reclassified according to the 2019 WHO classification based on morphology and Ki-67 index with analysis of the survival rates between the categories. Minimum follow-up period was 20months. Eighty-six patients with NENs of gastro-entero-pancreas were included, with median age group of 40-60years (age range 9 to 79years) and male:female ratio of 1.7:1. The tumour grade correlated with the TNM staging and most of the syndromic NETs were low grade. Eleven percent of the tumours were reclassified as well-differentiated G3NETs. The survival of G3 NETs was higher than NEC. Grading of NEN is vital for therapeutic decisions and for prognostication. Currently, morphology is the key to recognise the well-differentiated G3 NETs, but can be subject to interobserver variability. Molecular surrogates may play a role in accurately identifying these entities, the validity of which is warranted.

Interim Analysis of a Prospective Validation of 2 Blood-Based Genomic Assessments (PPQ and NETest) to Determine the Clinical Efficacy of 177Lu-DOTATATE in Neuroendocrine Tumors.

Reliable biomarkers for neuroendocrine tumor (NET) management during peptide receptor radionuclide therapy (PRRT) are lacking. We validated the role of 2 circulating biomarkers: the PRRT prediction quotient (PPQ) as a predictive marker for response and the NETest as a monitoring biomarker. Furthermore, we evaluated whether tissue-based genetic alterations are effective in predicting progression-free survival (PFS). Methods: Data were prospectively collected on patients at the Memorial Sloan Kettering Cancer Center with 177Lu-DOTATATE-treated somatostatin receptor (SSTR)-positive gastroenteropancreatic and lung NETs (n = 67; median age, 66 y; 52% female; 42% pancreatic, 39% small-bowel; 78% grade 1 or 2). All cases were metastatic (89% liver) and had received 1-8 prior treatments (median, 3), including somatostatin analogs (91%), surgery (55%), or chemotherapy (49%). Treatment response included PFS. According to RECIST, version 1.1, responders had stable disease or a partial response (disease-control rate) and nonresponders had progression. Blood was collected before each cycle and at follow-up. Samples were deidentified and assayed and underwent masked analyses. The gene expression assays included RNA isolation, real-time quantitative polymerase chain reaction, and multialgorithm analyses. The PPQ (positive predicts a responder; negative predicts a nonresponder) at baseline was determined. The NETest (0-100 score) was performed. Statistics were analyzed using Mann-Whitney U testing (2-tailed) or Kaplan-Meier survival testing (PFS). In patients with archival tumor tissue, next-generation sequencing was performed through an institutional platform (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets). Results: Forty-one patients (61%) were responders. PPQ accurately predicted 96% (64/67). The hazard ratio for prediction was 24.4 (95% CI, 8.2-72.5). Twelve-month disease control was 97% for PPQ-positive patients versus 26% for PPQ-negative patients (P < 0.0001). Median progression-free survival was not reached in those predicted to respond (PPQ-positive, n = 40) but was 8 mo in those predicted not to respond (PPQ-negative, n = 27). The NETest result in responders was 67 ± 25 at baseline and significantly (P < 0.05) decreased (-37 ± 44%) at follow-up. The NETest result in nonresponders was 44 ± 23 at baseline and significantly (P < 0.05) increased (+76% ± 56%) at progression. Overall, the NETest changes (increases or decreases) were 90% accurate. Thirty patients underwent next-generation sequencing. Tumors were microsatellite-stable, and the median mutational burden was 1.8. Alterations involved mainly the mTOR/PTEN/TSC pathway (30%). No relationship was associated with PRRT response. Conclusion: Our interim analysis confirmed that PPQ is an accurate predictor of 177Lu-DOTATATE responsiveness (radiosensitivity) and that NETest changes accurately correlated with treatment response. Tissue-based molecular genetic information had little value in PRRT prediction. Blood-based gene signatures may improve the management of patients undergoing 177Lu-DOTATATE by providing information on tumor radiosensitivity and disease course, thus allowing individualized strategies.

Gastroenteropancreatic Neuroendocrine Tumor Metastasis to the Heart: Evaluation of Imaging Manifestations

Neuroendocrine tumors (NET) may affect the heart by cardiac metastasis or carcinoid heart disease. NET metastasis to the heart is rare, with limited data characterizing it. We sought to evaluate 68Ga-DOTATATE PET scan imaging features and associated cardiac imaging characteristics where available in those with NET cardiac metastases. 68Ga-DOTATATE positron emission tomography (PET)/CT scans performed on patients with gastroenteropancreatic (GEP) NET at our institution were reviewed for cardiac involvement. Those identified with cardiac metastases had their electronic medical record, transthoracic echocardiogram (TTE) and cardiac magnetic resonance imaging (MRI) reviewed for characterization. From a total of 1426 68Ga-DOTATATE PET/CT scans performed on patients with GEP-NET, 25 (1.75%) had cardiac uptake consistent with metastasis. Of these, 22 had myocardial metastases (29 distinct myocardial lesions: left ventricle - 16, right ventricle - 6, and ventricular septum -7) and 3 had periradial lymph node involvement only. NET patients with cardiac metastases as identified by DOTATATE scan did not appear to have any hemodynamically significant TTE features, aside from those (2/25) who had concomitant carcinoid heart disease. Of the 14 patients who had available TTE for review, only one with high metastatic cardiac tumor burden had detectable cardiac mass. Of the 6 cases who had available MRI, all had metastatic cardiac lesions seen with excellent correlation with tumor localization on 68Ga-DOTATATE PET scan. 68Ga-DOTATATE PET has excellent capability for the diagnosis of cardiac NET metastasis. Cardiac MRI may provide further anatomic and tissue characterization evaluation. Those with myocardial NET metastases without carcinoid heart disease did not have significant hemodynamic effect based on echocardiographic criteria.

Psychological distress and resilience in patients with gastroenteropancreatic neuroendocrine tumor.

An increased incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has been reported in many countries. However, the prevalence and impact factors of psychological distress and resilience in patients with GEP-NETs are unclear. We recruited 200 patients with GEP-NETs to assess psychological distress and resilience. Measures comprised the Distress Thermometer, the Hospital Anxiety and Depression Scale, Connor-Davidson Resilience scale and Medical Coping Modes Questionnaire. Our results found that the prevalence of distress, anxiety, depression and low resilience were 31.5%, 31%, 17.8%, and 25.9%, respectively. Female patients were more likely to be distressed, as were those with NET Grade 1, were partly aware of diagnosis, and had known the diagnosis less than 3 months. Distress positively correlated with acceptance-resignation, and resilience positively correlated with confrontation and avoidance. Resilience negatively correlated with psychological distress. Patients coping disease with acceptance-resignation had higher odds of anxiety, depression, and low resilience. Our findings indicate that psychological distress and low resilience were common in patients with GEP-NETs. This suggests a need to integrate psychosocial domain into GEP-NETs clinical practice.

Patients with non-functional metastatic G2 pancreatic neuroendocrine tumor benefit from palliative surgery: A 20-year single-center retrospective analysis.

Pancreatic neuroendocrine tumor (pNET) is the most common subset (31.5%) of gastroenteropancreatic neuroendocrine tumor in China. Based on real-world data from a single center, the present study aimed to evaluate the influence of clinical characteristics, medical treatment and surgery on the survival of non-functional metastatic G2 pNET. In total, 114 metastatic non-functional G2 pNET patients, who were treated and followed up in the Department of Medical Oncology, Peking Union Medical College Hospital (PUMCH) from 2001 until 2019, were analyzed retrospectively. The primary endpoint, overall survival (OS), was calculated from the date of diagnosis to the date of death. The second endpoint, progression-free survival (PFS), was calculated from the date of diagnosis to the date of disease progression. Statistical data were analyzed to evaluate the effects of a clinical characteristic, medical treatment and surgery on OS and PFS. Sixty-nine (60.5%) patients were male and 87 (76.3%) were aged < 60 years. The liver was the most common metastatic organ, with a total of 84 cases (73.7%). With respect to surgery, 32 (28.1%) patients underwentradical surgery and 37 (32.5%) underwent palliative surgery. Survival analysis showed that the 5-year and 10-year survival rates were 79.36% and 70.0%, respectively. Univariate and multivariate Cox regression analyses suggested that both radical (p < .001/.003) and palliative surgery (p < .001/.002) significantly prolonged OS, as revealed by the Kaplan-Meier test (p < .001). Subgroup analysis showed that palliative resection also significantly improves the prognosis in patients with multiple liver metastases. However, the first-line systemic anti-tumor therapy option showed no statistical differences in the present study. Overall, patients with non-functional metastatic G2 pNET receiving palliative or radical surgery demonstrated significantly better survival. Prospective clinical trials are suggested to validate our findings.

Immune signature of pheochromocytoma and paraganglioma in context of neuroendocrine neoplasms associated with prognosis.

To understand prognostic immune cell infiltration signatures in neuroendocrine neoplasms (NENs), particularly pheochromocytoma and paraganglioma (PCPG), we analyzed tumor transcriptomic data from The Cancer Genome Atlas (TCGA) and other published tumor transcriptomic data of NENs. We used CIBERSORT to infer immune cell infiltrations from bulk tumor transcriptomic data from PCPGs, in comparison to gastroenteropancreatic neuroendocrine tumors (GEPNETs) and small cell lung carcinomas (SCLCs). PCPG immune signature was validated with NanoString immune panel in an independent cohort. Unsupervised clustering of the immune infiltration scores from CIBERSORT was used to find immune clusters. A prognostic immune score model for PCPGs and the other NENs were calculated as a linear combination of the estimated infiltration of activated CD8+/CD4+ T cells, activated NK cells, and M0 and M2 macrophages. In PCPGs, we found five dominant immune clusters, associated with M2 macrophages, monocytes, activated NK cells, M0 macrophages and regulatory T cells, and CD8+/CD4+ T cells respectively. Non-metastatic tumors were associated with activated NK cells and metastatic tumors were associated with M0 macrophages and regulatory T cells. In GEPNETs and SCLCs, M0 macrophages and regulatory T cells were associated with unfavorable outcomes and features, such as metastasis and high-grade tumors. The prognostic immune score model for PCPGs and the NENs could predict non-aggressive and non-metastatic diseases. In PCPGs, the immune score was also an independent predictor of metastasis-free survival in a multivariate Cox regression analysis. The transcriptomic immune signature in PCPG correlates with clinical features like metastasis and prognosis.

Impact of 68 Ga-FAPI-04 PET/CT on Staging and Therapeutic Management in Patients With Digestive System Tumors.

We aimed to determine the impact of fibroblast activation protein inhibitor (FAPI)-directed molecular imaging on staging and therapeutic management in patients affected with digestive system tumors when compared with guideline-compatible imaging (GCI). Thirty-two patients with tumors of the digestive system were included: colon adenocarcinoma, 2/32 (6.3%); hepatocellular carcinoma (HCC), 6/32 (18.8%); pancreatic duct adenocarcinoma (PDAC), 6/32 (18.8%), and gastroenteropancreatic neuroendocrine neoplasms, 18/32 (56.3%). All patients underwent GCI and 68 Ga-FAPI-04 PET/CT within median 4 days. Staging outcomes and subsequent treatment decisions were compared between GCI and 68 Ga-FAPI-04 PET/CT. Compared with GCI, 68 Ga-FAPI-04 PET/CT led to staging changes in 15/32 patients (46.9%). Among those, downstaging was recorded in 3/15 cases (20.0%) and upstaging in the remaining 12/15 patients (HCC, 4/12 [33.3%]; PDAC, 4/12 [33.3%]; neuroendocrine neoplasms, 3/12 [25%]; colon adenocarcinoma, 1/12 [8.3%]). Therapeutic management was impacted in 8/32 patients (25.0%), including 4 instances of major and 4 instances of minor therapeutic changes. The highest proportion of treatment modifications was observed in patients diagnosed with PDAC and HCC in 6/8 (75%). In patients affected with digestive system tumors, 68 Ga-FAPI-04 PET/CT resulted in staging changes in more than 46% and therapeutic modifications in 25% of the cases, in particular in patients with HCC and PDAC. In clinical routine, such findings may favor a more widespread adoption of FAP-directed imaging in those tumor types.

ODP300 c-MET expression in MEN1-associated neuroendocrine tumors

Abstract Multiple studies have shown that approximately 50-70% of patients with MEN1 die of causes directly related to MEN1 particularly gastroenteropancreatic (GEP) neuroendocrine tumors (NETs). While non-functional GEP-NETs are the most common in the general population, gastrinomas (40%) are the most common functional GEP-NETs in patients with MEN1. c-MET is a proto-oncogene that encodes for c-MET, a tyrosine kinase receptor which promotes tumor cell motility, proliferation, survival, invasion, and metastasis. Studies in patients with sporadic gastrinomas and pancreatic NETs (PNETs) have shown that c-MET expression correlates with decreased survival. While c-MET inhibitors are currently in various stages of investigation for treatment of carcinoids and sporadic PNETs, data regarding their efficacy in patients with MEN1-related GEP NETs is lacking. The majority of trials in patients with GEP-NETs exclude or do not report the number of patients with MEN1. Importantly, somatic MEN1 mutations are observed in 20-40% of sporadic NETs (gastrinomas, PNETs, lung NETs, etc.) but correlation of cMET expression with the presence of somatic or germline MEN1 mutations has not been reported. We sought to investigate the expression of c-MET in tumor tissue from germline MEN1 patients with metastatic GEP-NETs. Methods We identified subjects with a germline positive MEN1 mutation and pathologically confirmed distant metastasis who had a follow-up visit between 2018-2020. Of these, we selected subjects with available tissue specimens (including either multiple organ sources or different tumor types). Where available, we identified specimens from multiple source or tumor types. Immunohistochemistry (IHC) to detect c-MET was performed with anti-MET (Cell Signaling) using the DAKO IHC kit (Agilent). IHC slides were imaged and observed to score the level of c-MET staining (-, 1+ to 5+). A score of 3+ or higher was considered consistent with overexpression. We investigated if age at initial GEP-NET presentation, tumor type, tissue source, tumor grade, total number of surgeries for GEP-NET, number of sites of distant metastasis and disease status from overall GEP-NET burden over the preceding 12 months (stable/progressive) predicted c-MET expression. Results Eight subjects with available tissue specimens were identified, of which six had tissue from multiple organs while five had tissue from multiple tumor types. Six subjects (75%) showed increased expression of c-MET in one or more tumor specimen(s). The frequency of c-MET overexpression varied with tumor types – carcinoids (n=2/2; 100%), gastrinomas (n=3/5; 60%) and non-functional tumors (n=3/6; 50%). c-MET expression also varied among different tumors in the same patient. Tumor tissue from liver (n=2/2), duodenum (n=3/4), stomach (n=1/1), ovary (n=1/1), pancreas (n= 1/5), and lymph nodes (n=1/3), all showed over-expression of c-MET. No clear predictors of c-MET overexpression emerged. Conclusion Our finding suggests a role for c-MET expression in personalizing therapy for patients with MEN1-related NETs with distant metastases. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Sunday, June 12, 2022 12:48 p.m. - 12:53 p.m.

Imaging surveillance of completely resected gastroenteropancreatic neuroendocrine tumors is associated with high levels of radiation exposure

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

Autophagy Flux is Induced in Gastroenteropancreatic Neuroendocrine Neoplasms

Autophagy Flux is Induced in Gastroenteropancreatic Neuroendocrine Neoplasms

From morphology to molecular targets—the pathologist’s view in diagnosing gastroenteropancreatic neuroendocrine neoplasms

SummaryIn the last decade, a number of genetic alterations in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have been identified. In addition, differences in tumor morphology as well as proliferation index (Ki-67) or number of mitoses have led to changes in the classification of these neoplasms. According to the new World Health Organization (WHO) classification, GEP-NENs are now divided into two genetically and prognostically different categories: (i) well-differentiated neuroendocrine tumors (NET) subdivided into low (G1), intermediate (2) and high (G3) grade tumors, and (ii) poorly differentiated neuroendocrine carcinomas (NEC). In addition, a group of mixed neuroendocrine–non-neuroendocrine neoplasms (MiNEN) has been defined. This review focuses on the clinical, morphological, immunohistochemical and molecular findings of the GEP-NENs and their key diagnostic features that can help the pathologist to differentiate between tumors in this heterogeneous group. In challenging cases, additional immunohistochemical and/or molecular analysis can be helpful to determine the correct diagnosis and proper treatment for the patient.

Nomogram for preoperative estimation of histologic grade in gastrointestinal neuroendocrine tumors.

The treatment strategies and prognosis for gastroenteropancreatic neuroendocrine tumors were associated with tumor grade. Preoperative predictive grading could be of great benefit in the selection of treatment options for patients. However, there is still a lack of effective non-invasive strategies to detect gastrointestinal neuroendocrine tumors (GI-NETs) grading preoperatively. The data on 147 consecutive GI-NETs patients was retrospectively collected from January 1, 2012, to December 31, 2019. Logistic regression was used to construct a predictive model of gastrointestinal neuroendocrine tumor grading using preoperative laboratory and imaging parameters.The validity of the model was assessed by area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA). The factors associated with GI-NETs grading were age, tumor size, lymph nodes, neuron-specific enolase (NSE), hemoglobin (HGB) and sex, and two models were constructed by logistic regression for prediction. Combining these 6 factors, the nomogram was constructed for model 1 to distinguish between G3 and G1/2, achieving a good AUC of 0.921 (95% CI: 0.884-0.965), and the sensitivity, specificity, accuracy were 0.9167, 0.8256, 0.8630, respectively. The model 2 was to distinguish between G1 and G2/3, and the variables were age, tumor size, lymph nodes, NSE, with an AUC of 0.847 (95% CI: 0.799-0.915), and the sensitivity, specificity, accuracy were 0.7882, 0.8710, 0.8231, respectively. Two online web servers were established on the basis of the proposed nomogram to facilitate clinical use. Both models showed an excellent calibration curve through 1000 times bootstrapped dataset and the clinical usefulness were confirmed using decision curve analysis. The model served as a valuable non-invasive tool for differentiating between different grades of GI-NETs, personalizing the calculation which can lead to a rational treatment choice.

Inhibition of Ribonucleotide Reductase Subunit 2 (RRM2) Induces Radiosensitization in Gastroenteropancreatic Neuroendocrine Tumors

<h3>Purpose/Objective(s)</h3> Novel radiotherapy, such as Peptide Radionuclide Receptor Therapy, is becoming a milestone treatment for advanced Gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Ribonucleotide Reductase (RnR) subunit M2 (RRM2) activates RnR, the rate-limiting enzyme of DNA synthesis and repair. The purpose of this study was to determine the therapeutic rationale of RnR-targeted therapy and to evaluate 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP) as a radiosensitizer in treating GEP-NETs <i>in vitro</i> and <i>in vivo.</i> <h3>Materials/Methods</h3> (1) RRM2 inhibition was achieved by siRNA knockdown or a RRM2 specific inhibitor, 3-AP, in three GEP-NET cell lines (QGP-1, BON and NT-3) and patient-derived spheroids. Radiation (XRT) was delivered via an X-ray irradiator. Immunohistochemistry confirmed RRM2 expression in cell lines and spheroids, and western immunoblotting was used to examine phosphorylation of DNA repair pathways (DNA-PK, ATM, ATR), cell cycle arrest markers (Rb, Chk1, Chk2) and apoptotic protein (cleaved PARP). Proliferation assays and cell cycle analyses were used to evaluate cytostatic cellular response. Colorimetric survival and DNA fragmentation assays were used to investigate radiosensitization of RRM2 inhibition. (2) For <i>in vivo</i> studies<i>,</i> we utilized an athymic nude mouse GEP-NET xenograft model to assess tumor growth using a combination of 3-AP and XRT. <h3>Results</h3> (1) RRM2 receptor expression, predominantly in the cytoplasm, was noted in all GEP-NET cell lines and spheroids. Knockdown of RRM2 significantly inhibited cellular proliferation at 48 and 72h. Similarly, 3-AP inhibited cellular proliferation with an absolute IC-50 of 1240nM and 1297nM for QGP-1 and BON cells, respectively. Induction of ATM and DNA-PK phosphorylation, but not ATR, was detected with RRM2 inhibition. Importantly, siRNA RRM2 knockdown and 3-AP increased expression of cell cycle arrest markers (pRb, pChk1, and pChk2), and 3-AP (2500nM) arrested cells before entering the G2/M phase, significantly reducing the percentage of G2/M cells from 8.4% to 0.5% at 72h. Combination of RRM2 inhibition with XRT increased apoptosis as noted by increased expression of cleaved PARP. RRM2 inhibition by 3-AP potentiated XRT by reducing 14d cellular survival and inducing DNA fragmentation at 96h post-XRT. (2) We observed a significant decrease in tumor size in mice treated with XRT (2Gy) alone compared to control (146 mm² vs. 280 mm², respectively); combination treatment (2Gy XRT, followed by immediate 3-AP [10mg/kg] i.p. injection) demonstrated a further 48% decrease in tumor size compared to XRT alone. <h3>Conclusion</h3> Our studies demonstrate that inhibition of RRM2 potentiates XRT and results in a significant increase in apoptosis <i>in vitro</i> and a decrease in tumor size <i>in vivo</i>, suggesting enhanced cytotoxicity and radiosensitization. Selective RRM2 inhibition by 3-AP provides a potent therapeutic strategy as a radiosensitizer and offers a novel approach in treating advanced GEP-NETs.

Impact of Change in Body Composition during Follow-Up on the Survival of GEP-NET.

Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are heterogeneous rare diseases causing malnutrition and cachexia in which the study of body composition may have an impact in prognosis. Aim: Evaluation of muscle and fat tissues by computed tomography (CT) at the level of the third lumbar (L3 level) at diagnosis and at the end of follow-up in GET-NET patients and their relationships with clinical and biochemical variables as predictors of survival. Methodology: Ninety-eight GEP-NET patients were included. Clinical and biochemical parameters were evaluated. Total body, subcutaneous, visceral and total fat areas and very low-density, low-density, normal density, high-density, very high-density and total muscle areas were obtained from CT images. Results: Body composition measures and overall mortality correlated with age, ECOG (Eastern Cooperative Oncology Group performance status) metastases, lactate dehydrogenase (LDH), albumin and urea levels. Although there was no relationship between body composition variables at diagnosis and overall and specific mortality, an increase in low-density muscle and a decrease in normal-density muscle during follow-up were independently correlated to overall (p <0.05) and tumor-cause mortality (p < 0.05). Conclusion: Although body composition measures obtained by CT at diagnosis did not impact survival of GEP-NET patients, a loss of good quality muscle during follow-up was associated with an increased overall and tumor-related mortality. Nutritional status should therefore be supervised by nutrition specialists and an increase in good quality muscle could improve prognosis.

Novel preclinical gastroenteropancreatic neuroendocrine neoplasia models demonstrate the feasibility of mutation-based targeted therapy

PurposeGastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) form a rare and remarkably heterogeneous group of tumors. Therefore, establishing personalized therapies is eminently challenging. To achieve progress in preclinical drug development, there is an urgent need for relevant tumor models.MethodsWe successfully established three gastroenteropancreatic neuroendocrine tumor (GEP-NET) cell lines (NT-18P, NT-18LM, NT-36) and two gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) cell lines (NT-32 and NT-38). We performed a comprehensive characterization of morphology, NET differentiation, proliferation and intracellular signaling pathways of these five cell lines and, in addition, of the NT-3 GEP-NET cell line. Additionally, we conducted panel sequencing to identify genomic alterations suitable for mutation-based targeted therapy.ResultsWe found that the GEP-NEN cell lines exhibit a stable neuroendocrine phenotype. Functional kinome profiling revealed a higher activity of serine/threonine kinases (STK) as well as protein tyrosine kinases (PTK) in the GEP-NET cell lines NT-3 and NT-18LM compared to the GEP-NEC cell lines NT-32 and NT-38. Panel sequencing revealed a mutation in Death Domain Associated Protein (DAXX), sensitizing NT-18LM to the Ataxia telangiectasia and Rad3 related (ATR) inhibitor Berzosertib, and a mutation in AT-Rich Interaction Domain 1A (ARID1A), sensitizing NT-38 to the Aurora kinase A inhibitor Alisertib. Small interfering RNA-mediated knock down of DAXX in the DAXX wild type cell line NT-3 sensitized these cells to Berzosertib.ConclusionsThe newly established GEP-NET and GEP-NEC cell lines represent comprehensive preclinical in vitro models suitable to decipher GEP-NEN biology and pathogenesis. Additionally, we present the first results of a GEP-NEN-specific mutation-based targeted therapy. These findings open up new potentialities for personalized therapies in GEP-NEN.

Inflammation Related to Obesity in the Etiopathogenesis of Gastroenteropancreatic Neuroendocrine Neoplasms.

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare neoplasms, which, due to their heterogeneous nature, non-specific symptoms, and lack of specific tumor markers pose many diagnostic and clinical challenges. In recent years, the effectiveness of GEP-NEN diagnosis has increased, which is probably associated with the greater availability of diagnostic tests and the cooperation of many experienced specialists in various scientific disciplines. In addition to the possible genetic etiology, the cause of GEP-NET development is not fully understood. Inflammation and obesity are known risks that contribute to the development of many diseases. Chronic inflammation accompanying obesity affects the hormonal balance and cell proliferation and causes the impairment of the immune system function, leading to neoplastic transformation. This review explores the role of inflammation and obesity in GEP-NETs. The exact mechanisms inducing tumor growth are unknown; however, the profile of inflammatory factors released in the GEP-NET tumor microenvironment is responsible for the progression or inhibition of tumor growth. Both the excess of adipose tissue and the impaired function of the immune system affect not only the initiation of cancer but also reduce the comfort and lifetime of patients.