Preclinical drug studies in MEN1-related neuroendocrine neoplasms (MEN1-NENs)

Primary testicular neuroendocrine tumor with liver lymph node metastasis: A case report and review of the literature

BACKGROUND

Primary testicular neuroendocrine tumors (TNETs) are sporadic, accounting for only 0.23% of all testicular tumors. Few cases have been reported in the literature, and no uniform treatment protocol exists. We report a case of a primary TNET with liver lymph node metastasis diagnosed at the age of 24 years and discuss its clinicopathological features, diagnosis, differential diagnosis, treatment, and prognosis.

CASE SUMMARY

We report the case of a 24-year-old patient with a primary TNET with liver lymph node metastasis. The patient was found to have a right testicular swelling of about 3 cm × 4 cm in size with unclear borders and no testicular pressure pain seven years ago without any examination or treatment. One month ago, an ultrasound examination was performed for persistent enlargement of the right testis, which showed an occupying lesion of the right testis approximately 110 mm × 102 mm × 82 mm in size. Magnetic resonance imaging scan of the testis (plain scan) showed that the right testis was an occupying lesion with inhomogeneous density and mixed signal, the boundary was still clear, and the possibility of seminoma was considered; chest X-ray and computed tomography did not show any apparent abnormalities. The patient underwent radical orchiectomy, and the pathological examination suggested a right TNET with a typical carcinoid tumor histological type. One month after the surgery, the patient received nine cycles of lanreotide chemotherapy at a dose of 90 mg/mo without adverse effects. No distant lymph node or other organ metastases were detected at follow-up. He is in good physical condition and attends regular follow-up visits.

CONCLUSION

Neuroendocrine tumors are rare in clinical practice, and the diagnosis mainly relies on the characteristics of microscopic tumor cells and immunohistochemical features. Treatment involves radical orchiectomy. If it is accompanied by distant lymph node metastasis and the metastatic lesion can be resected, it should be surgically removed; if it cannot be resected, growth inhibitor analog octreotide or lanreotide chemotherapy can be administered to obtain good results, with close postoperative follow-up to prevent recurrence and metastasis.

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.

Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine?

Gastroenteropancreatic neuroendocrine neoplasia (GEPNEN) comprises clinically as well as prognostically diverse tumour entities often diagnosed at late stage. Current classification provides a uniform terminology and a Ki67-based grading system, thereby facilitating management. Advances in the study of genomic and epigenetic landscapes have amplified knowledge of tumour biology and enhanced identification of prognostic and potentially predictive treatment subgroups. Translation of this genomic and mechanistic biology into advanced GEPNEN management is limited. 'Targeted' treatments such as somatostatin analogues, peptide receptor radiotherapy, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are treatment options but predictive tools are lacking. The inability to identify clonal heterogeneity and define critical oncoregulatory pathways prior to therapy, restrict therapeutic efficacy as does the inability to monitor disease status in real time. Chemotherapy in the poor prognosis NEN G3 group, though associated with acceptable response rates, only leads to short-term tumour control and their molecular biology requires delineation to provide new and more specific treatment options.The future requires an exploration of the NEN tumour genome, its microenvironment and an identification of critical oncologic checkpoints for precise drug targeting. In the advance to personalised medical treatment of patients with GEPNEN, clinical trials need to be based on mechanistic and multidimensional characterisation of each tumour in order to identify the therapeutic agent effective for the individual tumour.This review surveys advances in NEN research and delineates the current status of translation with a view to laying the basis for a genome-based personalised medicine management of advanced GEPNEN.

Hypoxia Signaling in Cancer: From Basics to Clinical Practice

Cancer hypoxia, recognized as one of the most important hallmarks of cancer, affects gene expression, metabolism and ultimately tumor biology-related processes. Major causes of cancer hypoxia are deficient or inappropriate vascularization and systemic hypoxia of the patient (frequently induced by anemia), leading to a unique form of genetic reprogramming by hypoxia induced transcription factors (HIF). However, constitutive activation of oncogene-driven signaling pathways may also activate hypoxia signaling independently of oxygen supply. The consequences of HIF activation in tumors are the angiogenic phenotype, a novel metabolic profile and the immunosuppressive microenvironment. Cancer hypoxia and the induced adaptation mechanisms are two of the major causes of therapy resistance. Accordingly, it seems inevitable to combine various therapeutic modalities of cancer patients by existing anti-hypoxic agents such as anti-angiogenics, anti-anemia therapies or specific signaling pathway inhibitors. It is evident that there is an unmet need in cancer patients to develop targeted therapies of hypoxia to improve efficacies of various anti-cancer therapeutic modalities. The case has been opened recently due to the approval of the first-in-class HIF2α inhibitor.