Clinical Evaluation of Response to Octreotide and Chemotherapy in High-Grade Malignant Neuroendocrine Tumors and Promising In Vitro Preclinical Results with Pasireotide Doello, Kevin Chico Lozano, María Ángeles Quiñonero Muñoz, Francisco José Ortiz Quesada, Raúl Prados Salazar, José Carlos Mesas Hernández, Cristina Melguizo Alonso, Consolación Carcinoma Pasireotide Somatostatin receptors Background and Objectives: High-grade malignant neuroendocrine tumors (G3 NETs) and neuroendocrine carcinomas (NECs) are characterized by rapid proliferation, high metastatic capacity, and strong expression of somatostatin receptors (SSTRs). We aimed to analyze the presence of SSTRs in NET G3 and NEC, and to correlate their expression with the use of octreotide and pasireotide. Materials and Methods: For this purpose, we first performed a retrospective study of G3 NET and NEC patients, which included the determination of SSTR expression and response to octreotide treatment. Second, we selected the H69 small cell lung cancer cell line to determine the effect of octreotide and pasireotide. Results: Our results showed the traditional somatostatin analog (SSA) octreotide was ineffective in patients with NET G3 and NEC. On the other hand, RT-qPCR showed a high expression of SSTR2 and SSTR5 in H69 cells. Interestingly, while octreotide did not modify H69 cell proliferation, a strong inhibition of proliferation was detected with the use of pasireotide. Conclusions: In view of these results, a clinical trial in NET G3 and NEC patients using pasireotide is necessary to determine the usefulness of this drug in improving patient treatment. 2024-09-03T08:47:13Z 2024-09-03T08:47:13Z 2024-06-25 journal article Doello, K.; Chico, M.A.; Quiñonero, F.; Ortiz, R.; Prados, J.; Mesas, C.; Melguizo, C. Clinical Evaluation of Response to Octreotide and Chemotherapy in High-Grade Malignant Neuroendocrine Tumors and Promising In Vitro Preclinical Results with Pasireotide. Medicina 2024, 60, 1039. https://doi.org/10.3390/medicina60071039 https://hdl.handle.net/10481/93819 10.3390/medicina60071039 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI