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 p53wild type Neuroendocrine Tumor Cell Line GOT1

Neuroendocrinology. 2018;106(1):1-19. doi: 10.1159/000453369. Epub 2016 Nov 21.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism
  • Dose-Response Relationship, Drug
  • Drug Resistance, Neoplasm
  • Drug Therapy, Combination
  • E2F1 Transcription Factor / metabolism
  • Fluorouracil / pharmacology*
  • Humans
  • Isoquinolines / pharmacology*
  • Neuroendocrine Tumors / drug therapy*
  • Neuroendocrine Tumors / genetics
  • Neuroendocrine Tumors / metabolism
  • Piperazines / pharmacology*
  • Proto-Oncogene Proteins c-mdm2 / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-mdm2 / metabolism
  • Retinoblastoma Protein / metabolism
  • Signal Transduction / drug effects
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism


  • Antineoplastic Agents
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • E2F1 Transcription Factor
  • E2F1 protein, human
  • Isoquinolines
  • NVP-CGM097
  • Piperazines
  • Retinoblastoma Protein
  • Tumor Suppressor Protein p53
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2
  • Fluorouracil