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Intestinal neuroendocrine tumours (I-NETs) represent a non-negligible entity among intestinal neoplasms, with metastatic spreading usually present at the time of diagnosis. In this context, effective molecular actionable targets are still lacking. Through transcriptome analysis, we aim at refining the molecular taxonomy of I-NETs, also providing insights towards the identification of new therapeutic vulnerabilities. A retrospective series of 38 primary sporadic, surgically-resected I-NETs were assessed for transcriptome profiling of 20,815 genes. Transcriptome analysis detected 643 highly expressed genes. Unsupervised hierarchical clustering, differential expression analysis and gene set enriched analysis identified three different tumour clusters (CL): CL-A, CL-B, CL-C. CL-A showed the overexpression of ARGFX , BIRC8 , NANOS2 , and SSTR4 genes. Its most characterizing signatures were those related to cell-junctions, and activation of mTOR and WNT pathway. CL-A was also enriched in T CD8 + lymphocytes. CL-B showed the overexpression of PCSK1 , QPCT , ST18 , and TPH1 genes. Its most characterizing signatures were those related to adipogenesis, neuroendocrine metabolism, and splice site machinery-related processes. CL-B was also enriched in T CD4 + lymphocytes. CL-C showed the overexpression of ALB , ANG , ARG1 , and HP genes. Its most characterizing signatures were complement/coagulation and xenobiotic metabolism. CL-C was also enriched in M1/2 macrophages. These CL-based differences may have therapeutic implications in refining the management of I-NET patients. At last, we described a specific gene-set for differentiating I-NET from pancreatic NET. Our data represent an additional step for refining the molecular taxonomy of I-NET, identifying novel transcriptome subgroups with different biology and therapeutic opportunities. • 38 intestinal neuroendocrine tumors have been analyzed with transcriptomics. • Transcriptome analysis detected 643 highly expressed genes. • Three different tumour clusters (CL) were identified: CL-A, CL-B, and CL-C. • They correlate with different signaling pathways and tumor microenvironment. • A gene-set for differentiating I-NET from pancreatic NET is also reported. [ABSTRACT FROM AUTHOR]

Autophagy is generally regarded as a mechanism to promote cell survival. However, autophagy can occasionally be the mechanism responsible of cell demise. We have found that a concomitant depletion of glucose, nutrients and growth factors provoked cell death in a variety of cell lines. This death process was contingent upon caspase activation and was mediated by BAX/BAK proteins, thus indicating its apoptotic nature and the engagement of an intrinsic pathway. In order to abrogate autophagy, 3-methyladenine (3-MA), BECLIN-1 siRNA and Atg5 knock-out (Tet-Off type) approaches were alternatively employed. Irrespective of the procedure, at short times of starvation, we found that the ongoing autophagy was sensitizing cells to the permeabilization of the mitochondrial outer membrane (MOMP), caspase activation and, therefore, apoptosis. On the contrary, at longer times of starvation, autophagy displayed its characteristic pro-survival effect on cells. As far as we know, we provide the first experimental paradigm where time is the only variable determining the final outcome of autophagy. In other words, we have circumscribed in time the shift transforming autophagy from a cell death to a protection mechanism. Moreover, at short times, starvation-driven autophagy exacerbated the apoptotic cell death caused by several antitumor agents. In agreement with this fact, their apoptotic effects were greatly diminished by autophagy inhibition. The implications of these facts in tumor biology will be discussed. [ABSTRACT FROM AUTHOR]

PES (2-phenylethynesulfonamide) was initially identified as an inhibitor of p53 translocation to mitochondria and named Pifithrin-µ. Further studies showed that PES selectively killed tumour cells and was thus a promising anticancer agent. PES-induced cell death was characterised by a non-apoptotic, autophagosome-rich phenotype. We observed this phenotype via electron microscopy in wild type (wt) and double Bax -/- Bak -/- (DKO) mouse embryonic fibroblasts (MEFs) treated with PES. We excluded the involvement of effector caspases, BAX and BAK, in causing PES-triggered cell death. Therefore, apoptosis was ruled out as the lethal mode of action of PES. Surprisingly, MEFs containing BAX were significantly protected from PES treatments. BAX overexpression in Bax-/- MEFs confirmed this pro-survival effect. Moreover, this protective effect required the ability of BAX to localise to mitochondrial membranes. Conversely, mitochondrial fusion induced by treatment with Mdivi-1 conferred increased resistance to MEFs subjected to PES treatment. The involvement of BAX in the regulation of mitochondrial dynamics has been reported. We propose the promotion of mitochondrial fusion by BAX to be the pro-survival function attributed to BAX. [ABSTRACT FROM AUTHOR]

2-Phenylethynesulfonamide (PES) or pifithrin-μ is a promising anticancer agent with preferential toxicity for cancer cells. The type of cell death and the molecular cascades activated by this compound are controversial. Here, we demonstrate PES elicits a caspase- and BAX/BAK-independent non-necroptotic necrotic cell death, since it is not inhibited by necrostatin-1. This process is characterized by an early generation of reactive oxygen species (ROS) resulting in p53 up-regulation. Accordingly, thiolic antioxidants protect cells from PES-induced death. Furthermore, inhibiting the natural sources of glutathione with l -buthionine-sulfoximine (BSO) strongly cooperates with PES in triggering cytotoxicity. Genetically modified p53-null or p53 knocked-down cells show resistance to PES-driven necrosis. The predominant localization of p53 in chromatin-enriched fractions added to the up-regulation of the p53-responsive gene p21, strongly suggest the involvement of a transcription-dependent p53 program. On the other hand, we report an augmented production of ROS in p53-positive cells that, added to the increased p53 content in response to PES-elicited ROS, suggests that p53 and ROS are mutually regulated in response to PES. In sum, p53 up-regulation by ROS triggers a positive feedback loop responsible of further increasing ROS production and reinforcing PES-driven non-necroptotic necrosis. [ABSTRACT FROM AUTHOR]

The enantioselective reduction of ketoimines has been successfully realized, using trichlorosilane as the stoichiometric reducing agent in the presence of catalytic amounts of a Lewis base, specifically a Cinchona derivative. For the first time, a novel class of derivatives was studied, featuring a picolinamide unit bound to the alkaloid scaffold, further functionalized as quaternary ammonium salt at the quinuclidine ring. Excellent yields and from good to high enantioselectivities (up to 92% ee) were obtained in the reduction of ketoimines. The novel catalysts were successfully employed in the synthesis of an enantiomerically pure advanced precursor of the blockbuster drug Rivastigmine. [ABSTRACT FROM AUTHOR]

• Microsatellite instability (MSI) characterizes up to 20 % of colorectal cancers. • We studied a cohort of 104 MSI colorectal cancer. • Right-side and signet-ring cells histology are associated with nodal metastases. • Extranodal extension of nodal metastasis has a strong impact on survival. Colorectal cancer (CRC) with microsatellite instability (MSI) accounts for 15–18 % of all CRCs and represents the category with the best prognosis. This study aimed at determining any possible clinical/pathological features associated with a higher risk of nodal metastasization in MSI-CRC, and at defining any possible prognostic moderators in this setting. All surgically resected CRCs of the last 20 years (mono-institutional series) with a PCR-based diagnosis of MSI, with and without nodal metastasis, have been retrieved for histological review, which was performed following WHO guidelines. Furthermore, the most important prognostic moderators have been investigated with a survival analysis. The study of 33 cases of MSI-CRCs with nodal metastasis highlighted a high fidelity of histology maintenance between primary tumors and matched nodal metastases. At survival analysis, the strongest prognostic variable in MSI-CRCs with nodal metastasis was the extranodal extension (multivariate analysis, HR: 14.4, 95 %CI: 1.46−140.9, p = 0.022). Furthermore, through a comparison between nodal positive (33 cases) and nodal negative (71 cases) MSI-CRCs, right-sided location (p < 0.0001), pT4 stage (p = 0.0004) and signet-ring histology (p = 0.0089) emerged as parameters more commonly associated with nodal metastasization. These findings shed new light on the biology of MSI-CRC and can be of help for the prognostic stratification of MSI-CRC patients. [ABSTRACT FROM AUTHOR]