The aim of this study was to explore the possible involvement of the angiopoietin (Ang)-1, -2/Tie-2 system in the development, growth, and metastases evolution of gastroenteropancreaticneuroendocrine tumors (GEP-NETs). We prospectively examined the serum levels of Tie-2, Ang-1, and Ang-2 by ELISA in 42 patients with proven GEP-NETs and 27 controls. We also determined the expression of the Ang/Tie-2 system in freshly isolated peripheral blood monocytes and in tumor cells from malignant primary tumors and/or liver metastases samples from GEP-NET patients by flow cytometry and/or RT-PCR. Furthermore, the function of the Ang/Tie-2 system in monocytes from controls and patients was assessed by a chemotaxis assay. GEP-NET patients showed enhanced serum levels of soluble form of Tie-2 (sTie-2), Ang-1, and Ang-2 (P!0.05 in all cases), compared to controls. sTie-2 and Ang-2 levels were significantly higher in GEP-NETs with metastases compared to those with no metastases. In addition, a significant correlation was detected between Ang-2 levels and chromogranin A or sTie-2 concentrations or 5-hydroxy-indole acetic acid excretion (rZ0.71, rZ0.60, and rZ0.81 respectively, P!0.01 in all cases). Furthermore, we observed an enhanced expression of Ang-1, Ang-2, and Tie-2 in freshly isolated tumor cells from GEP-NET both by immunohistochemistry and by RT-PCR. Interestingly, an enhanced expression and function of Tie-2 was detected in monocytes from GEP-NET patients. Our data suggest that the Ang/Tie-2 system is involved in the growth and development of metastases of GEP-NETs, and that favors the recruitment of Tie-2 C monocytes to the tumor site, where they can promote inflammation and angiogenesis.

Preliminary results in our lab showed that naked Calcium Sulfide (CaS) nanoparticles (5.0nm) decreased cell proliferation in the carcinoma cell lines CRL‐2124. Objective: The objective of this study was to determine the IC50 and LD50 for CaS clusters (measuring < 3.0 nm) in the carcinoma cell lines CRL‐2124 and the normal fibroblasts CRL‐2522 by using the n3D BiOAssay (Biosciences, Inc.). Methods: A total of 100,000 cells per cell line were seeded in T‐75 flasks. When reaching 80% confluence, they were incubated with the n3D nano‐shuttles overnight (ON) at 37oC, 5% CO2, and 98% relative humidity. Next day, cells were trypsinized, counted, and seeded (1.4 ‐ 1.6 M/per well) in 6‐well plates using the n3D BiOAssay to levitate the cells. A total of 150,000 cells/well were seeded in a 96‐well plate in triplicates with a total volume of 300ul (150ul of cells, 120ul of media, and 30ul of the treatments). The treatments consist of doses ranging 10‐100 pmoles of CaS, 2% DMSO, or growth media. A 24‐hours recording consisting of four (4) photos per minute was collected with an iPod. The analyses were performed using the ImageJ software by measuring the “O” ring outer and inner diameters. Results: We observed changes in the diameters for the wells treated with CaS at different concentrations when compared to controls. Conclusions: We determined the IC50 and LD50 for adenocarcinoma and normal fibroblast cell lines. This step is important for the translation of the use of CaS as an anti‐cancer therapy when translated into in vivo models. Grant Funding Source: NIH‐NIGMSR25GM096955, NIH‐R25GM088023