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Oncogene. 2018 Jul;37(30):4058-4072. doi: 10.1038/s41388-018-0247-7. Epub 2018 Apr 26.

Exploiting TERT dependency as a therapeutic strategy for NRAS-mutant melanoma.

Author information

1
Molecular & Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA, USA.
2
Gene Expression & Regulation Program, The Wistar Institute, Philadelphia, PA, USA.
3
Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
4
Immunology, Microenvironment & Metastasis Program, The Wistar Institute, Philadelphia, PA, USA.
5
Molecular & Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA, USA. jvillanueva@wistar.org.
6
Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA. jvillanueva@wistar.org.

Abstract

Targeting RAS is one of the greatest challenges in cancer therapy. Oncogenic mutations in NRAS are present in over 25% of melanomas and patients whose tumors harbor NRAS mutations have limited therapeutic options and poor prognosis. Thus far, there are no clinical agents available to effectively target NRAS or any other RAS oncogene. An alternative approach is to identify and target critical tumor vulnerabilities or non-oncogene addictions that are essential for tumor survival. We investigated the consequences of NRAS blockade in NRAS-mutant melanoma and show that decreased expression of the telomerase catalytic subunit, TERT, is a major consequence. TERT silencing or treatment of NRAS-mutant melanoma with the telomerase-dependent telomere uncapping agent, 6-thio-2'-deoxyguanosine (6-thio-dG), led to rapid cell death, along with evidence of both telomeric and non-telomeric DNA damage, increased ROS levels, and upregulation of a mitochondrial antioxidant adaptive response. Combining 6-thio-dG with the mitochondrial inhibitor Gamitrinib attenuated this adaptive response and more effectively suppressed NRAS-mutant melanoma. Our study uncovers a robust dependency of NRAS-mutant melanoma on TERT, and provides proof-of-principle for a new combination strategy to combat this class of tumors, which could be expanded to other tumor types.

PMID:
29695835
PMCID:
PMC6062502
DOI:
10.1038/s41388-018-0247-7
[Indexed for MEDLINE]
Free PMC Article

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