Exploring the MEN1 dependent modulation of caspase 8 and caspase 3 in human pancreatic and murine embryo fibroblast cells

MEN1 mutation causes pancreatic neuroendocrine neoplasia and benign malignancies of the parathyroid, the adrenal cortex and pituitary gland. The transcriptional activity of its product menin promotes the expression of genes deputed to several cellular mechanism including cell death. Here, we focused on its implication in the activation of the initiator and executioner caspases after staurosporine mediated cell death in 2D and 3D human and murine cell models. The administration of staurosporine, a well-known inducer of apoptotic cell death, caused a significant reduction of BON1, QGP1 and HPSC2.2 cell viability. The transient knockdown of MEN1, performed by using a specific siRNA, caused a significant down-regulation of CDKN1A and TP53 transcripts. The treatment with 1 µM of staurosporine caused also a significant down-regulation of MEN1 and was able to restore the basal expression of TP53 only in QGP1 cells. Transient or permanent MEN1 inactivation caused a decrease of caspase 8 activity in BON1, HPSC2.2 cells and MEN1^-/- MEFs treated with staurosporine. Caspase 3/7 activity was suppressed after administration of staurosporine in MEN1 knocked down HPSC2.2 and MEN1^-/- MEFs as well. The cleaved caspase 8 and caspase 3 decreased in human cells after MEN1 knockdown and in MEN1^-/- MEFs. The treatment with staurosporine caused a reduction of the size of MEN1^+/+ MEFs spheroids. Instead, MEN1^-/- MEFs spheroids did not show any significant reduction of their size. In conclusion, MEN1 controls the activity of the initiator caspase 8 and the executioner caspase 3 in human and murine cells. Restoring of a functional MEN1 and interfering with the apoptotic mechanism could represent a future strategy for the treatment of MEN1-related malignancies.

Exploring the surgical landscape of pancreatic neuroendocrine neoplasia in Austria: Results from the ASSO pNEN study group

INTRODUCTION

Pancreatic neuroendocrine neoplasia (pNEN) show increasing incidence and management is complex due to biological heterogeneity. Most publications report isolated high-volume single-centre data. This Austrian multi-centre study on surgical management of pNENs provides a comprehensive real-life picture of quality indicators, recurrence-patterns, survival factors and systemic treatments.

METHODS

Retrospective, national cohort-study from 7 medium-/high-volume centres in Austria, coordinated under the auspices of the Austrian Society of Surgical Oncology (ASSO).

RESULTS

Two-hundred patients underwent resection for pNEN, 177 had non-functioning tumours and 31 showed stage 4 disease. Participating centres were responsible for 2/3 of pNEN resections in Austria within the last years. The mean rate of completeness of variables was 98.6%. Ninety-days mortality was 3.5%, overall rate of complications was 42.5%. Morbidity did not influence long-term survival. The 5-year overall-survival (OS) was 81.3%, 10-year-OS 52.5% and 5-year recurrence-free-survival (RFS) 69.8%. Recurrence was most common in the liver (68.1%). Four out of five patients with recurrence underwent further treatment, most commonly with medical therapy or chemotherapy. Multivariable analysis revealed grading (HR:2.7) and metastasis (HR:2.5) as significant factors for relapse. Tumours-size ≥2 cm (HR:5.9), age ≥60 years (HR:3.1), metastasis (HR:2.3) and grading (HR:2.0) were associated with OS. Tumours <2 cm showed 93.9% 10-year-OS, but 33% had G2/G3 grading, 12.5% positive lymph-nodes and 4.7% metastasis at diagnosis, each associated with significant worse survival.

CONCLUSION

Resection of pNENs in Austria is performed with internationally comparable safety. Analysed factors allow for risk-stratification in clinical treatment and future prospective trials. A watch-and-wait strategy purely based on tumour-size cannot be recommended.

Global microRNA profiling of pancreatic neuroendocrine neoplasias

BACKGROUND

Pancreatic neuroendocrine neoplasms (pNEN) are rare tumors with a poor prognosis. Although increasing data have accumulated on the molecular pathology of pNEN, very scarce data exist on microRNAs in pNEN and no data are published on microRNAs as potential biomarkers of pNEN in serum. This study aimed to identify microRNA signatures of pNEN in tissue and serum.

MATERIALS AND METHODS

We included tissue samples from 37 patients with pNEN, 9 patients with non-neoplastic pancreatic pathology, seven samples of micro-dissected pancreatic islets and serum samples of 27 patients with pNEN, as well as of 15 healthy volunteers. MicroRNA expression profiles were established using real-time quantitative Polymerase Chain reaction (PCR) for 754 microRNAs.

RESULTS

MicroRNA signatures differed between pNEN, pancreatic islets and total pancreas, with virtually no overlap between the groups of de-regulated microRNAs. Expression of miR-642 correlated with Ki67 (MiB1) score and miR-210 correlated with metastatic disease. When comparing microRNA levels in serum from patients with pNEN and healthy volunteers, 13 microRNAs were more abundant in the serum of patients. MiR-193b was also up-regulated in pNEN tissue when compared to pancreatic islets and remained significantly increased in serum even when corrected for multiple testing.

CONCLUSION

Evaluation of microRNAs appears to be promising in the assessment of pNEN. In particular, miR-193b, which is also increased in serum, may be a potential new biomarker of pNEN.