Endocrine Abstracts

Neuroendocrine neoplasms (NENs) are rare tumour showing a wide spectrum of clinical behaviours. Therapeutic options available for NET treatment are rarely curative and mostly palliative, as NETs frequently show resistance to pharmacological therapy. Cancers develop in complex tissue environments, which they depend on. Tumour-associated macrophages (TAMs) are a major cellular component of the tumour microenvironment. Two polarized state of macrophages are described in literature: M1 (anti-tumour promoting effects) and M2 (pro-tumour promoting effects). The role of macrophages in pancreatic (Pan-) and pulmonary (Lung-) NENs is poorly understood. So, a better understand of the role of macrophages could provide new insights into the behaviour of pulmonary and pancreatic NETs, more effective therapeutics strategies that could overcome pharmacological resistance and provide new immune markers. In NEN TAMs are not well characterized. We aimed to characterized TAM within Pan- and Lung-NEN. Taking advantage of multiparametric flow cytometry analysis we found that the TAMs were, in large part, M2-like. Theyalso express HLADR, CD115, CCR2 and CX3CR1.To assess the effects of M1, M2 macrophages on biological behaviour of NEN, primary cells and NEN cell lines QGP-1 (pancreatic-NEN) and H727 (pulmonary-NEN) were cultured with macrophages conditioned medium (CM). We found out that CM of M1 macrophages strongly decreased cell proliferation of both Pan- and Lung-NEN primary cells. Effect confirmed in cell lines (QGP-1, H727), where M1 CM significantly decreased tumorigenesis of cells. Interestingly, the CM of NEN cell lines promoted the differentiation of macrophages into an M2 phenotype. A key role in supporting tumours growth is played also by stimuli, such as cytokines. We discovered that QGP-1 and H727 cells secrete specific chemokines and this secretion was influenced by treatment with M1 CM. Sene Set Enrichment Analysis on RNAseq data from QGP-1 and H727 cells treated with M1 CM revealed an enrichment in the genset for inflammatory response, apoptosis and p53 pathway. Results confirmed by mass spectrometry analysis for M1 CM-specific proteins. The supernatant was enriched, compare to control, in complement factors, lysozymes, cathepsin, and hypoxia and stress induction stimuli. A better understanding of the immunological characteristics of the malignancy is necessary to explore and test immunotherapeutic strategies. Using multiparametric flow cytometry technique we decided to perform the immunophenotype of peripheral blood from NEN patients. The present study demonstrated differences of the amount and immunophenotype of circulating granulocytes, lymphocytes, monocytes and their subpopulations between NEN patients and healthy individuals.