AXL/AKT axis mediated-resistance to BRAF inhibitor depends on PTEN status in melanoma
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Updated: Feb 13, 2026

Analysis of Lymph Node Volume by Ultra-High-Frequency Ultrasound Imaging in the Braf/Pten Genetically Engineered Mouse Model of Melanoma
Published on: September 8, 2021
Qiang Zuo1,2, Jing Liu2, Liping Huang1,2
1Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institutes, National Institutes of Health, Bethesda, MD, 20892-4264, USA.
Abstract:
Multiple genetic mutations within melanoma not only cause lesion-specific responses to targeted therapy but also alter the molecular route of resistance to that therapy. Inactivation of PTEN occurs in up to 30% of melanomas, frequently with a concurrent activating BRAF mutation. PTEN loss regulates both acquired and intrinsic drug resistance. Here we show that AXL/AKT axis mediated-resistance to BRAF inhibitor (BRAFi) depends upon PTEN status in melanoma. Hyperactivation of both ERK and AKT pathways was associated with BRAFi resistance in melanoma with wildtype PTEN. The PTEN-impaired melanoma cells required only the ERK resistance mechanism. Moreover, we identified AXL as a key upstream effector of AKT pathway-associated resistance to BRAFi in melanoma with wildtype PTEN, but not in melanoma with impaired PTEN. Notably, we confirmed that blocking AXL by shRNA and a small molecular inhibitor could rescue the sensitivity of resistant melanoma cells with wildtype PTEN to BRAFi and inhibit their growth in vitro and in vivo. Our study has uncovered a mechanism by which PTEN status contributes to acquired resistance to BRAFi and offers a rational strategy to guide clinical testing in pre-identified subsets of patients who relapse during treatment with BRAFi. The identified protein AXL represents a promising therapeutic target for BRAF mutant melanoma patients with wildtype PTEN.
Insights
PTEN status dictates resistance to BRAF inhibitors (BRAFi) in melanoma. Blocking the AXL/AKT pathway can restore BRAFi sensitivity in wildtype PTEN melanoma, offering a new therapeutic strategy.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Melanoma harbors genetic mutations influencing targeted therapy response and resistance.
- PTEN inactivation, common in melanoma, impacts drug resistance.
- BRAF inhibitors (BRAFi) are a key melanoma therapy, but resistance develops.
Purpose of the Study:
- To investigate the role of PTEN status in mediating resistance to BRAF inhibitors (BRAFi) in melanoma.
- To identify molecular mechanisms driving BRAFi resistance based on PTEN status.
- To explore AXL as a therapeutic target for overcoming BRAFi resistance.
Main Methods:
- Analysis of melanoma cell lines with varying PTEN status.
- Investigating the roles of AXL, AKT, and ERK pathways in BRAFi resistance.
- Utilizing shRNA and small molecule inhibitors to block AXL.
- In vitro and in vivo experiments to assess therapeutic efficacy.
Main Results:
- AXL/AKT axis-mediated resistance to BRAFi is dependent on PTEN status.
- Melanoma with wildtype PTEN exhibits resistance via both ERK and AKT pathways, with AXL being a key effector of AKT-driven resistance.
- PTEN-impaired melanoma cells primarily rely on ERK for resistance.
- Blocking AXL restores BRAFi sensitivity and inhibits tumor growth in wildtype PTEN melanoma.
Conclusions:
- PTEN status is a critical determinant of acquired resistance mechanisms to BRAFi in melanoma.
- The AXL/AKT pathway is a significant contributor to BRAFi resistance in PTEN wildtype melanoma.
- Targeting AXL presents a promising therapeutic strategy for BRAF-mutant melanoma patients with wildtype PTEN who relapse on BRAFi therapy.
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