Reuther, C, Heinzle, V, Nölting, S, Herterich, S, Hahner, S, Halilovic, Ensar, Jeay, Sebastien, Wuerthner, Jens, Spöttl, G, Maurer, J and Auernhammer, CJ (2018) The HDM2 (MDM2) Inhibitor NVP-CGM097 inhibits tumor cell proliferation and shows additive effects with 5-fluorouracil on the p53 - p21 - Rb - E2F1 cascade in the p53wildtype neuroendocrine tumor cell line GOT1. Neuroendocrinology : an international journal for brain-hormone interactions, 106. pp. 1-19. ISSN 1423-0194

Abstract

Background/aims: The tumor suppressor p53 is depleted in many tumor cells by the E3 ubiquitin ligase mouse double minute 2 homolog (MDM2) through MDM2/p53 interaction. A novel target for inhibiting p53 degradation and for causing reexpression of p53wild type is inhibition of MDM2. The small molecule NVP-CGM097 is a novel MDM2 inhibitor. We investigated MDM2 inhibition as a target in neuroendocrine tumor cells in vitro.

Methods: Human neuroendocrine tumor cell lines from the pancreas (BON1), lung (NCI-H727), and midgut (GOT1) were incubated with the MDM2 inhibitor NVP-CGM097 (Novartis) at concentrations from 4 to 2,500 nM.

Results: While p53wild type GOT1 cells were sensitive to NVP-CGM097, p53mutated BON1 and p53mutated NCI-H727 cells were resistant to NVP-CGM097. Incubation of GOT1 cells with NVP-CGM097 at 100, 500, and 2,500 nM for 96 h caused a significant decline in cell viability to 84.9 ± 9.2% (p < 0.05), 77.4 ± 6.6% (p < 0.01), and 47.7 ± 9.2% (p < 0.01). In a Western blot analysis of GOT1 cells, NVP-CGM097 caused a dose-dependent increase in the expression of p53 and p21 tumor suppressor proteins and a decrease in phospho-Rb and E2F1. Experiments of co-incubation of NVP-CGM097 with 5-fluorouracil, temozolomide, or everolimus each showed additive antiproliferative effects in GOT1 cells. NVP-CGM097 and 5-fluorouracil increased p53 and p21 expression in an additive manner.

Conclusions: MDM2 inhibition seems a promising novel therapeutic target in neuroendocrine tumors harboring p53wild type. Further investigations should examine the potential role of MDM2 inhibitors in neuroendocrine tumor treatment.

Keywords: 5-Fluorouracil; Everolimus; GOT1; MDM2 inhibitor; NVP-CGM097; Neuroendocrine tumor; Temozolomide; p21; p53.

Item Type:	Article
Date Deposited:	14 Nov 2020 00:45
Last Modified:	14 Nov 2020 00:45
URI:	https://oak.novartis.com/id/eprint/26171