Clinical management of typical and atypical carcinoids/neuroendocrine tumors in ENETS centres of excellence (CoE): Survey from the ENETS lung NET task force.

Lung carcinoid tumours are neuroendocrine neoplasms originating from the bronchopulmonary tract's neuroendocrine cells, accounting for only 1%-3% of all lung cancers but 30% of all neuroendocrine tumours. The incidence of lung carcinoids, both typical and atypical, has been increasing over the years due to improved diagnostic methods and increased awareness among clinicians and pathologists. The most recent WHO classification includes a subgroup of lung carcinoids with atypical morphology and higher mitotic count and/or Ki67 labelling index. Despite appropriate surgery, the 5-year survival rate for atypical carcinoids barely exceeds 50%-70%. The role of adjuvant therapy in lung carcinoids is not well-defined, and clinical decisions are generally based on the presence of high-risk features. Long-term follow-up is essential to monitor for recurrence, although the optimal follow-up protocol remains unclear. To address the lack of consensus in clinical management decisions, the European Neuroendocrine Tumor Society (ENETS) initiated a survey among 20 expert centres. The survey identified varied opinions on approaches to imaging, surgery, use of adjuvant therapy, and follow-up protocols. Notably, the absence of dedicated multidisciplinary lung neuroendocrine tumour boards in some centres was evident. Experts agreed on the need for a prospective adjuvant trial in high-risk patients, emphasizing the feasibility of such a study. In conclusion, the study highlights the need for a more uniform adoption of existing guidelines in the management of lung carcinoid tumours and emphasizes the importance of international collaboration to advance research and patient care. Close collaboration between healthcare providers and patients is vital for effective long-term surveillance and management of these rare tumours.

Spliceosomic dysregulation in pancreatic cancer uncovers splicing factors PRPF8 and RBMX as novel candidate actionable targets.

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer, characterized by late diagnosis and poor treatment response. Surgery is the only curative approach, only available to early-diagnosed patients. Current therapies have limited effects, cause severe toxicities, and minimally improve overall survival. Understanding of splicing machinery alterations in PDAC remains incomplete. Here, we comprehensively examined 59 splicing machinery components, uncovering dysregulation in pre-mRNA processing factor 8 (PRPF8) and RNA-binding motif protein X-linked (RBMX). Their downregulated expression was linked to poor prognosis and malignancy features, including tumor stage, invasion and metastasis, and associated with poorer survival and the mutation of key PDAC genes. Experimental modulation of these splicing factors in pancreatic cancer cell lines reverted their expression to non-tumor levels and resulted in decreased key tumor-related features. These results provide evidence that the splicing machinery is altered in PDAC, wherein PRPF8 and RBMX emerge as candidate actionable therapeutic targets.

Integrative clinical, hormonal, and molecular data associate with invasiveness in acromegaly: REMAH study.

INTRODUCTION: Growth hormone (GH)-secreting pituitary tumors (GHomas) are the most common acromegaly cause. At diagnosis, most of them are macroadenomas, and up to 56% display cavernous sinus invasion. Biomarker assessment associated with tumor growth and invasion is important to optimize their management. OBJECTIVES: The study aims to identify clinical/hormonal/molecular biomarkers associated with tumor size and invasiveness in GHomas and to analyze the influence of pre-treatment with somatostatin analogs (SSAs) or dopamine agonists (DAs) in key molecular biomarker expression. METHODS: Clinical/analytical/radiological variables were evaluated in 192 patients from the REMAH study (ambispective multicenter post-surgery study of the Spanish Society of Endocrinology and Nutrition). The expression of somatostatin/ghrelin/dopamine system components and key pituitary/proliferation markers was evaluated in GHomas after the first surgery. Univariate/multivariate regression studies were performed to identify association between variables. RESULTS: Eighty percent of patients harbor macroadenomas (63.8% with extrasellar growth). Associations between larger and more invasive GHomas with younger age, visual abnormalities, higher IGF1 levels, extrasellar/suprasellar growth, and/or cavernous sinus invasion were found. Higher GH1 and lower PRL/POMC/CGA/AVPR1B/DRD2T/DRD2L expression levels (P < .05) were associated with tumor invasiveness. Least Absolute Shrinkage and Selection Operator's penalized regression identified combinations of clinical and molecular features with areas under the curve between 0.67 and 0.82. Pre-operative therapy with DA or SSAs did not alter the expression of any of the markers analyzed except for DRD1/AVPR1B (up-regulated with DA) and FSHB/CRHR1 (down-regulated with SSAs). CONCLUSIONS: A specific combination of clinical/analytical/molecular variables was found to be associated with tumor invasiveness and growth capacity in GHomas. Pre-treatment with first-line drugs for acromegaly did not significantly modify the expression of the most relevant biomarkers in our association model. These findings provide valuable insights for risk stratification and personalized management of GHomas.

A proposed clinical classification for pituitary neoplasms to guide therapy and prognosis.

No comprehensive classification system that guides prognosis and therapy of pituitary adenomas exists. The 2022 WHO histopathology-based classification system can only be applied to lesions that are resected, which represent few clinically significant pituitary adenomas. Many factors independent of histopathology provide mechanistic insight into causation and influence prognosis and treatment of pituitary adenomas. We propose a new approach to guide prognosis and therapy of pituitary adenomas by integrating clinical, genetic, biochemical, radiological, pathological, and molecular information for all adenomas arising from anterior pituitary cell lineages. The system uses an evidence-based scoring of risk factors to yield a cumulative score that reflects disease severity and can be used at the bedside to guide pituitary adenoma management. Once validated in prospective studies, this simple manageable classification system could provide a standardised platform for assessing disease severity, prognosis, and effects of therapy on pituitary adenomas.

Altered CELF4 splicing factor enhances pancreatic neuroendocrine tumors aggressiveness influencing mTOR and everolimus response.

Pancreatic neuroendocrine tumors (PanNETs) comprise a heterogeneous group of tumors with growing incidence. Recent molecular analyses provided a precise picture of their genomic and epigenomic landscape. Splicing dysregulation is increasingly regarded as a novel cancer hallmark influencing key tumor features. We have previously demonstrated that splicing machinery is markedly dysregulated in PanNETs. Here, we aimed to elucidate the molecular and functional implications of CUGBP ELAV-like family member 4 (CELF4), one of the most altered splicing factors in PanNETs. CELF4 expression was determined in 20 PanNETs, comparing tumor and non-tumoral adjacent tissue. An RNA sequencing (RNA-seq) dataset was analyzed to explore CELF4-linked interrelations among clinical features, gene expression, and splicing events. Two PanNET cell lines were employed to assess CELF4 function in vitro and in vivo. PanNETs display markedly upregulated CELF4 expression, which is closely associated with malignancy features, altered expression of key tumor players, and distinct splicing event profiles. Modulation of CELF4 influenced proliferation in vitro and reduced in vivo xenograft tumor growth. Interestingly, functional assays and RNA-seq analysis revealed that CELF4 silencing altered mTOR signaling pathway, enhancing the effect of everolimus. We demonstrate that CELF4 is dysregulated in PanNETs, where it influences tumor development and aggressiveness, likely by modulating the mTOR pathway, suggesting its potential as therapeutic target.

Use and perceived utility of [18 F]FDG PET/CT in neuroendocrine neoplasms: A consensus report from the European Neuroendocrine Tumor Society (ENETS) Advisory Board Meeting 2022.

Somatostatin receptor (SST) PET/CT is the gold standard for well-differentiated neuroendocrine tumours (NET) imaging. Higher grades of neuroendocrine neoplasms (NEN) show preferential [18F]FDG (FDG) uptake, and even low-grade NET may de-differentiate over time. FDG PET/CT's prognostic role is widely accepted; however, its impact on clinical decision-making remains controversial and its use varies widely. A questionnaire-based survey on FDG PET/CT use and perceived decision-making utility in NEN was submitted to the ENETS Advisory Board Meeting attendees (November 2022, response rate = 70%). In 3/15 statements, agreement was higher than 75%: (i) FDG was considered useful in NET, irrespective of grade, in case of mis-matched lesions (detectable on diagnostic CT but negative/faintly positive on SST PET/CT), especially if PRRT is contemplated (80%); (ii) in NET G3 if curative surgery is considered (82%); and (iii) in NEC prior to surgery with curative intent (98%). FDG use in NET G3, even in the presence of matched lesions, as a baseline for response assessment was favoured by 74%. Four statements obtained more than 60% consensus: (i) FDG use in NET G3 if locoregional therapy is considered (65%); (ii) in neuroendocrine carcinoma before initiating active therapy as a baseline for response assessment (61%); (iii) biopsy to re-assess tumour grade prior to a change in therapeutic management (68%) upon detection of FDG-positivity on the background of a prior G1-2 NET; (iv) 67% were in favour to reconsider PRRT to treat residual SST-positive lesions after achieving complete remission on FDG of the SST-negative disease component. Multidisciplinary opinion broadly supports the use of FDG PET/CT for characterisation of disease biology and to guide treatment selection across a range of indications, despite the lack of full consensus in many situations. This may reflect existing clinical access due to lack of reimbursement or experience with this investigation, which should be addressed by further research.

Altered splicing machinery in lung carcinoids unveils NOVA1, PRPF8 and SRSF10 as novel candidates to understand tumor biology and expand biomarker discovery.

BACKGROUND: Lung neuroendocrine neoplasms (LungNENs) comprise a heterogeneous group of tumors ranging from indolent lesions with good prognosis to highly aggressive cancers. Carcinoids are the rarest LungNENs, display low to intermediate malignancy and may be surgically managed, but show resistance to radiotherapy/chemotherapy in case of metastasis. Molecular profiling is providing new information to understand lung carcinoids, but its clinical value is still limited. Altered alternative splicing is emerging as a novel cancer hallmark unveiling a highly informative layer. METHODS: We primarily examined the status of the splicing machinery in lung carcinoids, by assessing the expression profile of the core spliceosome components and selected splicing factors in a cohort of 25 carcinoids using a microfluidic array. Results were validated in an external set of 51 samples. Dysregulation of splicing variants was further explored in silico in a separate set of 18 atypical carcinoids. Selected altered factors were tested by immunohistochemistry, their associations with clinical features were assessed and their putative functional roles were evaluated in vitro in two lung carcinoid-derived cell lines. RESULTS: The expression profile of the splicing machinery was profoundly dysregulated. Clustering and classification analyses highlighted five splicing factors: NOVA1, SRSF1, SRSF10, SRSF9 and PRPF8. Anatomopathological analysis showed protein differences in the presence of NOVA1, PRPF8 and SRSF10 in tumor versus non-tumor tissue. Expression levels of each of these factors were differentially related to distinct number and profiles of splicing events, and were associated to both common and disparate functional pathways. Accordingly, modulating the expression of NOVA1, PRPF8 and SRSF10 in vitro predictably influenced cell proliferation and colony formation, supporting their functional relevance and potential as actionable targets. CONCLUSIONS: These results provide primary evidence for dysregulation of the splicing machinery in lung carcinoids and suggest a plausible functional role and therapeutic targetability of NOVA1, PRPF8 and SRSF10.

The Concise Guide to PHARMACOLOGY 2023/24: G protein-coupled receptors.

The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and about 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (https://www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/bph.16177. G protein-coupled receptors are one of the six major pharmacological targets into which the Guide is divided, with the others being: ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.

Splicing alterations in pancreatic ductal adenocarcinoma: a new molecular landscape with translational potential.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal cancers worldwide, mainly due to its late diagnosis and lack of effective therapies, translating into a low 5-year 12% survival rate, despite extensive clinical efforts to improve outcomes. International cooperative studies have provided informative multiomic landscapes of PDAC, but translation of these discoveries into clinical advances are lagging. Likewise, early diagnosis biomarkers and new therapeutic tools are sorely needed to tackle this cancer. The study of poorly explored molecular processes, such as splicing, can provide new tools in this regard. Alternative splicing of pre-RNA allows the generation of multiple RNA variants from a single gene and thereby contributes to fundamental biological processes by finely tuning gene expression. However, alterations in alternative splicing are linked to many diseases, and particularly to cancer, where it can contribute to tumor initiation, progression, metastasis and drug resistance. Splicing defects are increasingly being associated with PDAC, including both mutations or dysregulation of components of the splicing machinery and associated factors, and altered expression of specific relevant gene variants. Such disruptions can be a key element enhancing pancreatic tumor progression or metastasis, while they can also provide suitable tools to identify potential candidate biomarkers and discover new actionable targets. In this review, we aimed to summarize the current information about dysregulation of splicing-related elements and aberrant splicing isoforms in PDAC, and to describe their relationship with the development, progression and/or aggressiveness of this dismal cancer, as well as their potential as therapeutic tools and targets.

European Neuroendocrine Tumour Society (ENETS) 2023 guidance paper for nonfunctioning pancreatic neuroendocrine tumours.

This ENETS guidance paper for well-differentiated nonfunctioning pancreatic neuroendocrine tumours (NF-Pan-NET) has been developed by a multidisciplinary working group, and provides up-to-date and practical advice on the management of these tumours. Using the extensive experience of centres treating patients with NF-Pan-NEN, the authors of this guidance paper discuss 10 troublesome questions in everyday clinical practice. Our many years of experience in this field are still being verified in the light of the results of new clinical, which set new ways of proceeding in NEN. The treatment of NF-Pan-NEN still requires a decision of a multidisciplinary team of specialists in the field of neuroendocrine neoplasms.

Pituitary adenoma or neuroendocrine tumour: the need for an integrated prognostic classification.

In the 2022 fifth edition of the WHO Classification of Endocrine Tumours and of Central Nervous System Tumours, pituitary adenomas are reclassified as neuroendocrine tumours (NETs). This change confers an oncology label to neoplasms that are overwhelmingly benign. A comprehensive clinical classification schema is required to guide prognosis, therapy and outcomes for all patients with pituitary adenomas. Pituitary adenomas and NETs exhibit some morphological and ultrastructural similarities. However, unlike NETs, pituitary adenomas are highly prevalent, yet indolent and rarely become malignant. This Perspective presents the outcomes of an interdisciplinary international workshop that addressed the merit and clinical implications of the classification change of pituitary adenoma to NET. Many non-histological factors provide mechanistic insight and influence the prognosis and treatment of pituitary adenoma. We recommend the development of a comprehensive classification that integrates clinical, genetic, biochemical, radiological, pathological and molecular information for all anterior pituitary neoplasms.

European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes.

This ENETS guidance paper aims to provide practical advice to clinicians for the diagnosis, treatment and follow-up of functioning syndromes in pancreatic neuroendocrine tumours (NET). A NET-associated functioning syndrome is defined by the presence of a clinical syndrome combined with biochemical evidence of inappropriately elevated hormonal levels. Different hormonal syndromes can be encountered in pancreatic NET patients, including insulinoma, gastrinoma as well as the rare glucagonoma, VIPoma, ACTHoma, PTHrPoma, carcinoid syndrome, calcitoninoma, GHRHoma and somatostatinoma. The recommendations provided in this paper focus on the biochemical, genetic and imaging work-up as well as therapeutic management of the individual hormonal syndromes in well-differentiated, grade 1-3, functioning NET with the primary tumour originating in the pancreas, and for specific subtypes also in the duodenum.

Metformin and simvastatin exert additive antitumour effects in glioblastoma via senescence-state: clinical and translational evidence.

BACKGROUND: Glioblastoma is one of the most devastating and incurable cancers due to its aggressive behaviour and lack of available therapies, being its overall-survival from diagnosis ∼14-months. Thus, identification of new therapeutic tools is urgently needed. Interestingly, metabolism-related drugs (e.g., metformin/statins) are emerging as efficient antitumour agents for several cancers. Herein, we evaluated the in vitro/in vivo effects of metformin and/or statins on key clinical/functional/molecular/signalling parameters in glioblastoma patients/cells. METHODS: An exploratory-observational-randomized retrospective glioblastoma patient cohort (n = 85), human glioblastoma/non-tumour brain human cells (cell lines/patient-derived cell cultures), mouse astrocytes progenitor cell cultures, and a preclinical xenograft glioblastoma mouse model were used to measure key functional parameters, signalling-pathways and/or antitumour progression in response to metformin and/or simvastatin. FINDINGS: Metformin and simvastatin exerted strong antitumour actions in glioblastoma cell cultures (i.e., proliferation/migration/tumoursphere/colony-formation/VEGF-secretion inhibition and apoptosis/senescence induction). Notably, their combination additively altered these functional parameters vs. individual treatments. These actions were mediated by the modulation of key oncogenic signalling-pathways (i.e., AKT/JAK-STAT/NF-κB/TGFß-pathways). Interestingly, an enrichment analysis uncovered a TGFß-pathway activation, together with AKT inactivation, in response to metformin + simvastatin combination, which might be linked to an induction of the senescence-state, the associated secretory-phenotype, and to the dysregulation of spliceosome components. Remarkably, the antitumour actions of metformin + simvastatin combination were also observed in vivo [i.e., association with longer overall-survival in human, and reduction in tumour-progression in a mouse model (reduced tumour-size/weight/mitosis-number, and increased apoptosis)]. INTERPRETATION: Altogether, metformin and simvastatin reduce aggressiveness features in glioblastomas, being this effect significantly more effective (in vitro/in vivo) when both drugs are combined, offering a clinically relevant opportunity that should be tested for their use in humans. FUNDING: Spanish Ministry of Science, Innovation and Universities; Junta de Andalucía; CIBERobn (CIBER is an initiative of Instituto de Salud Carlos III, Spanish Ministry of Health, Social Services and Equality).

A longitudinal study of free leptin index in pre-eclamptic pregnancies.

The ratio between circulating levels of leptin and soluble leptin receptor (sOB-R), the free leptin index (FLI), is used as a marker of leptin resistance. Therefore, the aim of our study was to investigate the FLI in mild pre-eclamptic pregnancies in a nested case-control study within a prospective observational study. Circulating levels of leptin and sOB-R levels rise significantly during pregnancy in healthy (p < 0.05) (n = 46) and pre-eclamptic pregnancies (p < 0.05) (n = 20). Serum levels of leptin were significantly higher in pre-eclamptic compared to healthy pregnancies at second and third trimesters of pregnancy (p < 0.05). Additionally, serum levels of sOB-R were significantly lower in pre-eclamptic pregnancies during the second and third trimesters of pregnancy compared to healthy pregnancies (p < 0.05). Moreover, we found that FLI did not vary significantly during pregnancy in healthy women (p > 0.05), while it increases in pre-eclamptic pregnancies (p < 0.05). Indeed, FLI was significantly higher at second and third trimesters of pregnancy in pre-eclamptic compared to healthy pregnancies (p < 0.05). In addition, FLI was significantly higher in the luteal phase compared with the follicular phase of the menstrual cycle in eumenorrheic women (p < 0.05). Receiver operating characteristic (ROC) curve analysis revealed the ability of leptin (AUC = 0.72) and FLI (AUC = 0.67) as a reliable predictor for mild pre-eclampsia during the second trimester of pregnancy. In conclusion, our findings show that FLI were significantly increased in mild pre-eclamptic pregnancies and allowed us to hypothesize that this rise might alter leptin bioavailability and bioactivity which might lead to the sympathetic hyperactivity and the hypertensive disorders during pregnancy.

PRPF8 increases the aggressiveness of hepatocellular carcinoma by regulating FAK/AKT pathway via fibronectin 1 splicing.

Hepatocellular carcinoma (HCC) pathogenesis is associated with alterations in splicing machinery components (spliceosome and splicing factors) and aberrant expression of oncogenic splice variants. We aimed to analyze the expression and potential role of the spliceosome component PRPF8 (pre-mRNA processing factor 8) in HCC. PRPF8 expression (mRNA/protein) was analyzed in a retrospective cohort of HCC patients (n = 172 HCC and nontumor tissues) and validated in two in silico cohorts (TCGA and CPTAC). PRPF8 expression was silenced in liver cancer cell lines and in xenograft tumors to understand the functional and mechanistic consequences. In silico RNAseq and CLIPseq data were also analyzed. Our results indicate that PRPF8 is overexpressed in HCC and associated with increased tumor aggressiveness (patient survival, etc.), expression of HCC-related splice variants, and modulation of critical genes implicated in cancer-related pathways. PRPF8 silencing ameliorated aggressiveness in vitro and decreased tumor growth in vivo. Analysis of in silico CLIPseq data in HepG2 cells demonstrated that PRPF8 binds preferentially to exons of protein-coding genes, and RNAseq analysis showed that PRPF8 silencing alters splicing events in multiple genes. Integrated and in vitro analyses revealed that PRPF8 silencing modulates fibronectin (FN1) splicing, promoting the exclusion of exon 40.2, which is paramount for binding to integrins. Consistent with this finding, PRPF8 silencing reduced FAK/AKT phosphorylation and blunted stress fiber formation. Indeed, HepG2 and Hep3B cells exhibited a lower invasive capacity in membranes treated with conditioned medium from PRPF8-silenced cells compared to medium from scramble-treated cells. This study demonstrates that PRPF8 is overexpressed and associated with aggressiveness in HCC and plays important roles in hepatocarcinogenesis by altering FN1 splicing, FAK/AKT activation and stress fiber formation.

Tumor suppressor role of RBM22 in prostate cancer acting as a dual-factor regulating alternative splicing and transcription of key oncogenic genes.

Prostate cancer (PCa) is one of the leading causes of cancer-related deaths among men. Consequently, the identification of novel molecular targets for treatment is urgently needed to improve patients' outcomes. Our group recently reported that some elements of the cellular machinery controlling alternative-splicing might be useful as potential novel therapeutic tools against advanced PCa. However, the presence and functional role of RBM22, a key spliceosome component, in PCa remains unknown. Therefore, RBM22 levels were firstly interrogated in 3 human cohorts and 2 preclinical mouse models (TRAMP/Pbsn-Myc). Results were validated in in silico using 2 additional cohorts. Then, functional effects in response to RBM22 overexpression (proliferation, migration, tumorspheres/colonies formation) were tested in PCa models in vitro (LNCaP, 22Rv1, and PC-3 cell-lines) and in vivo (xenograft). High throughput methods (ie, RNA-seq, nCounter PanCancer Pathways Panel) were performed in RBM22 overexpressing cells and xenograft tumors. We found that RBM22 levels were down-regulated (mRNA and protein) in PCa samples, and were inversely associated with key clinical aggressiveness features. Consistently, a gradual reduction of RBM22 from non-tumor to poorly differentiated PCa samples was observed in transgenic models (TRAMP/Pbsn-Myc). Notably, RBM22 overexpression decreased aggressiveness features in vitro, and in vivo. These actions were associated with the splicing dysregulation of numerous genes and to the downregulation of critical upstream regulators of cell-cycle (i.e., CDK1/CCND1/EPAS1). Altogether, our data demonstrate that RBM22 plays a critical pathophysiological role in PCa and invites to suggest that targeting negative regulators of RBM22 expression/activity could represent a novel therapeutic strategy to tackle this disease.

The uprise of RNA biology in neuroendocrine neoplasms: altered splicing and RNA species unveil translational opportunities.

Neuroendocrine neoplasms (NENs) comprise a highly heterogeneous group of tumors arising from the diffuse neuroendocrine system. NENs mainly originate in gastrointestinal, pancreatic, and pulmonary tissues, and despite being rare, show rising incidence. The molecular mechanisms underlying NEN development are still poorly understood, although recent studies are unveiling their genomic, epigenomic and transcriptomic landscapes. RNA was originally considered as an intermediary between DNA and protein. Today, compelling evidence underscores the regulatory relevance of RNA processing, while new RNA molecules emerge with key functional roles in core cell processes. Indeed, correct functioning of the interrelated complementary processes comprising RNA biology, its processing, transport, and surveillance, is essential to ensure adequate cell homeostasis, and its misfunction is related to cancer at multiple levels. This review is focused on the dysregulation of RNA biology in NENs. In particular, we survey alterations in the splicing process and available information implicating the main RNA species and processes in NENs pathology, including their role as biomarkers, and their functionality and targetability. Understanding how NENs precisely (mis)behave requires a profound knowledge at every layer of their heterogeneity, to help improve NEN management. RNA biology provides a wide spectrum of previously unexplored processes and molecules that open new avenues for NEN detection, classification and treatment. The current molecular biology era is rapidly evolving to facilitate a detailed comprehension of cancer biology and is enabling the arrival of personalized, predictive and precision medicine to rare tumors like NENs.

Spliceosomic dysregulation unveils NOVA1 as a candidate actionable therapeutic target in pancreatic neuroendocrine tumors.

Dysregulation of the splicing machinery is emerging as a hallmark in cancer due to its association with multiple dysfunctions in tumor cells. Inappropriate function of this machinery can generate tumor-driving splicing variants and trigger oncogenic actions. However, its role in pancreatic neuroendocrine tumors (PanNETs) is poorly defined. In this study we aimed to characterize the expression pattern of a set of splicing machinery components in PanNETs, and their relationship with aggressiveness features. A qPCR-based array was first deployed to determine the expression levels of components of the major (n = 13) and minor spliceosome (n = 4) and associated splicing factors (n = 27), using a microfluidic technology in 20 PanNETs and non-tumoral adjacent samples. Subsequently, in vivo and in vitro models were applied to explore the pathophysiological role of NOVA1. Expression analysis revealed that a substantial proportion of splicing machinery components was altered in tumors. Notably, key splicing factors were overexpressed in PanNETs samples, wherein their levels correlated with clinical and malignancy features. Using in vivo and in vitro assays, we demonstrate that one of those altered factors, NOVA1, is tightly related to cell proliferation, alters pivotal signaling pathways and interferes with responsiveness to drug treatment in PanNETs, suggesting a role for this factor in the aggressiveness of these tumors and its suitability as therapeutic target. Altogether, our results unveil a severe alteration of the splicing machinery in PanNETs and identify the putative relevance of NOVA1 in tumor development/progression, which could provide novel avenues to develop diagnostic biomarkers and therapeutic tools for this pathology.

Cytokines and Lymphoid Populations as Potential Biomarkers in Locally and Borderline Pancreatic Adenocarcinoma.

Despite its relative low incidence, PDAC is one of the most aggressive and lethal types of cancer, being currently the seventh leading cause of cancer death worldwide, with a 5-year survival rate of 10.8%. Taking into consideration the necessity to improve the prognosis of these patients, this research has been focused on the discovery of new biomarkers. For this purpose, patients with BL and resectable disease were recruited. Serum cytokines and growth factors were monitored at different time points using protein arrays. Immune cell populations were determined by flow cytometry in peripheral blood as well as by immunohistochemistry (IHC) in tumor tissues. Several cytokines were found to be differentially expressed between the study subgroups. In the BL disease setting, two different scores were proven to be independent prognostic factors for progression-free survival (PFS) (based on IL-10, MDC, MIF, and eotaxin-3) and OS (based on eotaxin-3, NT-3, FGF-9, and IP10). In the same context, CA19-9 was found to play a role as independent prognostic factor for OS. Eotaxin-3 and MDC cytokines for PFS, and eotaxin-3, NT-3, and CKß8-1 for OS, were shown to be predictive biomarkers for nab-paclitaxel and gemcitabine regimen. Similarly, oncostatin, BDNF, and IP10 cytokines were proven to act as predictive biomarkers regarding PFS, for FOLFIRINOX regimen. In the resectable cohort, RANTES, TIMP-1, FGF-4, and IL-10 individually differentiated patients according to their cancer-associated survival. Regarding immune cell populations, baseline high levels of circulating B lymphocytes were related to a significantly longer OS, while these levels significantly decreased as progression occurred. Similarly, baseline high levels of helper lymphocytes (CD4+), low levels of cytotoxic lymphocytes (CD8+), and a high CD4/CD8 ratio, were related to a significantly longer PFS. Finally, high levels of CD4+ and CD8+ intratumoural infiltration was associated with significantly longer PFS. In conclusion, in this study we were able to identify several prognostic and predictive biomarker candidates in patients diagnosed of resectable or BL PDAC.