An Overview of Circulating Biomarkers in Neuroendocrine Neoplasms: A Clinical Guide.

Neuroendocrine neoplasms (NENs) are a heterogeneous group of diseases that are characterized by different behavior and clinical manifestations. The diagnosis and management of this group of tumors are challenging due to tumor complexity and lack of precise and widely validated biomarkers. Indeed, the current circulating mono-analyte biomarkers (such as chromogranin A) are ineffective in describing such complex tumors due to their poor sensitivity and specificity. In contrast, multi-analytical circulating biomarkers (including NETest) are emerging as more effective tools to determine the real-time profile of the disease, both in terms of accurate diagnosis and effective treatment. In this review, we will analyze the capabilities and limitations of different circulating biomarkers focusing on three relevant questions: (1) accurate and early diagnosis; (2) monitoring of disease progression and response to therapy; and (3) detection of early relapse.

Extrahepatic Distal Cholangiocarcinoma vs. Pancreatic Ductal Adenocarcinoma: Histology and Molecular Profiling for Differential Diagnosis and Treatment.

Pancreatic ductal adenocarcinoma (PDAC) and distal cholangiocarcinoma (dCCA) are very aggressive tumors with a high mortality rate. Pancreas and distal bile ducts share a common embryonic development. Hence, PDAC and dCCA exhibit similar histological features that make a differential diagnosis during routine diagnostic practice challenging. However, there are also significant differences, with potential clinical implications. Even if PDAC and dCCA are generally associated with poor survival, patients with dCCA seem to present a better prognosis. Moreover, although precision oncology-based approaches are still limited in both entities, their most important targets are different and include alterations affecting BRCA1/2 and related genes in PDAC, as well as HER2 amplification in dCCA. Along this line, microsatellite instability represents a potential contact point in terms of tailored treatments, but its prevalence is very low in both tumor types. This review aims at defining the most important similarities and differences in terms of clinicopathological and molecular features between these two entities, also discussing the main theranostic implications derived from this challenging differential diagnosis.

Reversible Monoacylglycerol Lipase Inhibitors: Discovery of a New Class of Benzylpiperidine Derivatives.

Monoacylglycerol lipase (MAGL) is the enzyme responsible for the metabolism of 2-arachidonoylglycerol in the brain and the hydrolysis of peripheral monoacylglycerols. Many studies demonstrated beneficial effects deriving from MAGL inhibition for neurodegenerative diseases, inflammatory pathologies, and cancer. MAGL expression is increased in invasive tumors, furnishing free fatty acids as pro-tumorigenic signals and for tumor cell growth. Here, a new class of benzylpiperidine-based MAGL inhibitors was synthesized, leading to the identification of 13, which showed potent reversible and selective MAGL inhibition. Associated with MAGL overexpression and the prognostic role in pancreatic cancer, derivative 13 showed antiproliferative activity and apoptosis induction, as well as the ability to reduce cell migration in primary pancreatic cancer cultures, and displayed a synergistic interaction with the chemotherapeutic drug gemcitabine. These results suggest that the class of benzylpiperidine-based MAGL inhibitors have potential as a new class of therapeutic agents and MAGL could play a role in pancreatic cancer.

Prolonged exposure to simulated microgravity promotes stemness impairing morphological, metabolic and migratory profile of pancreatic cancer cells: a comprehensive proteomic, lipidomic and transcriptomic analysis.

BACKGROUND: The impact of the absence of gravity on cancer cells is of great interest, especially today that space is more accessible than ever. Despite advances, few and contradictory data are available mainly due to different setup, experimental design and time point analyzed. METHODS: Exploiting a Random Positioning Machine, we dissected the effects of long-term exposure to simulated microgravity (SMG) on pancreatic cancer cells performing proteomic, lipidomic and transcriptomic analysis at 1, 7 and 9 days. RESULTS: Our results indicated that SMG affects cellular morphology through a time-dependent activation of Actin-based motility via Rho and Cdc42 pathways leading to actin rearrangement, formation of 3D spheroids and enhancement of epithelial-to-mesenchymal transition. Bioinformatic analysis reveals that SMG may activates ERK5/NF-κB/IL-8 axis that triggers the expansion of cancer stem cells with an increased migratory capability. These cells, to remediate energy stress and apoptosis activation, undergo a metabolic reprogramming orchestrated by HIF-1α and PI3K/Akt pathways that upregulate glycolysis and impair ß-oxidation, suggesting a de novo synthesis of triglycerides for the membrane lipid bilayer formation. CONCLUSIONS: SMG revolutionizes tumor cell behavior and metabolism leading to the acquisition of an aggressive and metastatic stem cell-like phenotype. These results dissect the time-dependent cellular alterations induced by SMG and pave the base for altered gravity conditions as new anti-cancer technology.

MRP5 nitration by NO-releasing gemcitabine encapsulated in liposomes confers sensitivity in chemoresistant pancreatic adenocarcinoma cells.

Pancreatic ductal adenocarcinoma (PDAC) is a therapy recalcitrant disease characterized by the aberrations in multiple genes that drive pathogenesis and drug chemoresistance. In this study, we synthesize a library of seven novel nitric oxide-releasing gemcitabine pro-drugs (NO-GEMs) in order to improve the effectiveness of GEM by exploiting the therapeutic effects of NO. Among these NO-GEM pro-drugs we select 5b as the most effective compound in GEM-resistant PDAC cells. After its encapsulation in liposomes for drug delivery the intracellular NO level increases and nitration associated to activity inhibition of the multidrug resistance associated protein 5 (MRP5; ABCC5) occurs. This results in GEM intracellular accumulation and enhanced apoptotic cell death in GEM-resistant PDAC cells, which express MRP5 at higher levels than GEM-sensitive cells. Our results support the development of a new anti-tumoral strategy to efficiently affect GEM-resistant PDAC cells based on the usage of NO-GEM pro-drugs.

Mutant p53-Associated Molecular Mechanisms of ROS Regulation in Cancer Cells.

The TP53 tumor suppressor gene is the most frequently altered gene in tumors and an increasing number of studies highlight that mutant p53 proteins can acquire oncogenic properties, referred to as gain-of-function (GOF). Reactive oxygen species (ROS) play critical roles as intracellular messengers, regulating numerous signaling pathways linked to metabolism and cell growth. Tumor cells frequently display higher ROS levels compared to healthy cells as a result of their increased metabolism as well as serving as an oncogenic agent because of its damaging and mutational properties. Several studies reported that in contrast with the wild type protein, mutant p53 isoforms fail to exert antioxidant activities and rather increase intracellular ROS, driving a pro-tumorigenic survival. These pro-oxidant oncogenic abilities of GOF mutant p53 include signaling and metabolic rewiring, as well as the modulation of critical ROS-related transcription factors and antioxidant systems, which lead ROS unbalance linked to tumor progression. The studies summarized here highlight that GOF mutant p53 isoforms might constitute major targets for selective therapeutic intervention against several types of tumors and that ROS enhancement driven by mutant p53 might represent an "Achilles heel" of cancer cells, suggesting pro-oxidant drugs as a therapeutic approach for cancer patients bearing the mutant TP53 gene.

Regulation of Autophagy by Nuclear GAPDH and Its Aggregates in Cancer and Neurodegenerative Disorders.

Several studies indicate that the cytosolic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has pleiotropic functions independent of its canonical role in glycolysis. The GAPDH functional diversity is mainly due to post-translational modifications in different amino acid residues or due to protein-protein interactions altering its localization from cytosol to nucleus, mitochondria or extracellular microenvironment. Non-glycolytic functions of GAPDH include the regulation of cell death, autophagy, DNA repair and RNA export, and they are observed in physiological and pathological conditions as cancer and neurodegenerative disorders. In disease, the knowledge of the mechanisms regarding GAPDH-mediated cell death is becoming fundamental for the identification of novel therapies. Here, we elucidate the correlation between autophagy and GAPDH in cancer, describing the molecular mechanisms involved and its impact in cancer development. Since autophagy is a degradative pathway associated with the regulation of cell death, we discuss recent evidence supporting GAPDH as a therapeutic target for autophagy regulation in cancer therapy. Furthermore, we summarize the molecular mechanisms and the cellular effects of GAPDH aggregates, which are correlated with mitochondrial malfunctions and can be considered a potential therapeutic target for various diseases, including cancer and neurodegenerative disorders.