Related Experiment Video

Updated: Nov 12, 2025

Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells
06:09

Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells

Published on: June 7, 2019

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The Molecular Context of Vulnerability for CDK9 Suppression in Triple Wild-Type Melanoma

Samantha M Guhan1, Michael Shaughnessy2, Anpuchchelvi Rajadurai2

  • 1Harvard Medical School, Boston, Massachusetts, USA; Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, USA.

The Journal of Investigative Dermatology
|March 22, 2021
PubMed

Insights

Targeting CDK9 selectively inhibits therapeutically orphaned BRAF/NRAS/NF1 wild-type melanomas. This approach depletes survival factors by blocking transcription, offering a new strategy for treatment-resistant cancers.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Therapeutics

Background:

  • Approximately 50% of melanoma tumors lack druggable targets, rendering them unresponsive to current therapies.
  • Targeting transcriptional dependencies, or oncogene starvation, is a promising strategy for these therapeutically orphaned tumors.
  • Inhibition of transcriptional regulators can deplete essential survival factors.

Purpose of the Study:

  • To identify therapeutic strategies for melanomas lacking druggable targets.
  • To investigate the efficacy of Cyclin-Dependent Kinase 9 (CDK9) inhibition in wild-type BRAF/NRAS/NF1 melanomas.
  • To explore the underlying molecular mechanisms of CDK9 inhibitor selectivity.

Main Methods:

  • A drug screen identified CDK9 inhibitor SNS-032 for its selectivity against wild-type (wt) BRAF/NRAS melanomas.
  • In vitro studies utilized a CDK9 degrader (TS-032) and a selective CDK9 kinase inhibitor (NVP-2).
  • RNA sequencing and analysis of The Cancer Genome Atlas (TCGA) data were employed.

Main Results:

  • Both TS-032 and NVP-2 demonstrated greater suppression of BRAFwt/NRASwt/NF1wt melanomas compared to mutant melanomas at 500 nM.
  • RNA sequencing revealed that CDK9 inhibition converges on a cell cycle network involving transcriptional regulators like E2F family members.
  • TCGA data supported an oncogenic role for E2F1 and E2F2 in wt BRAF/NRAS/NF1 tumors, linked to CDK9.

Conclusions:

  • Selective targeting of CDK9 via transcriptional blockade is effective against therapeutically orphaned BRAF/NRAS/NF1 wt melanomas.
  • CDK9 inhibition represents a viable therapeutic approach for treatment-resistant melanoma subtypes.
  • The findings highlight the importance of targeting transcriptional dependencies in cancer therapy.

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