Related Experiment Video

Updated: May 26, 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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Combinational Inhibition of MEK and AKT Synergistically Induces Melanoma Stem Cell Apoptosis and Blocks NRAS Tumor

Ryyan Alobaidi1,2, Nusrat Islam1, Toni Olkey1

  • 1Department of Biochemistry and Molecular & Cellular Biology, Georgetown University School of Medicine, Washington, DC 20057, USA.

Cells
|February 25, 2025
PubMed

Insights

CD133 promotes melanoma cell survival by activating AKT signaling, conferring resistance to trametinib. Combination therapy with AKT and MEK inhibitors overcomes this resistance, offering a potential treatment for NRAS-mutant melanoma.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Stem Cells

Background:

  • Malignant melanoma is a lethal skin cancer driven by melanoma-initiating cells (MICs).
  • CD133 is a stem cell marker overexpressed in melanoma, linked to drug resistance.
  • MEK inhibitor trametinib shows limited efficacy in some melanoma models.

Purpose of the Study:

  • Investigate the role of CD133 in mediating resistance to trametinib in NRAS-mutant melanoma.
  • Elucidate the molecular mechanisms by which CD133 confers anti-apoptotic activity.
  • Evaluate combination therapy with MEK and AKT inhibitors for NRAS-mutant melanoma.

Main Methods:

  • CRISPR-Cas9 CD133 knockout and Doxycycline-inducible CD133 re-expression in patient-derived BAKP melanoma cells (NRASQ61K).
  • Western blot analysis of apoptosis-related proteins (p-AKT, p-BAD, BAX, caspase-3).
  • Cell viability (XTT assay), apoptosis, colony formation, and in vivo mouse xenograft studies.

Main Results:

  • CD133 knockout enhanced trametinib-induced apoptosis by reducing p-AKT/p-BAD and increasing BAX.
  • CD133 re-expression reduced trametinib-induced apoptosis, increasing p-AKT/p-BAD and decreasing BAX/caspase-3 activation.
  • Combination of trametinib and pan-AKT inhibitor capivasertib reduced cell survival and tumor growth, independent of CD133 status.
  • CD133 activates AKT/BAD signaling, suppressing apoptosis and promoting drug resistance.

Conclusions:

  • CD133 promotes melanoma cell survival and drug resistance via AKT pathway activation.
  • Targeting both AKT and MAPK pathways with trametinib and capivasertib is a promising strategy for NRAS-mutant melanoma.
  • Combination therapy overcomes CD133-mediated resistance in melanoma stem cells.
Keywords:
CRISPR-Cas9NRAScapivasertibdrug resistancetrametinibxenograft

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