Abstract
Abstract
Background
The mitogen-activated protein kinase (MAPK) signaling pathway is frequently hyperactivated in malignant melanoma and its inhibition has proved to be an efficient treatment option for cases harboring BRAFV600 mutations (BRAFMut). However, there is still a significant need for effective targeted therapies for patients with other melanoma subgroups characterized by constitutive MAPK activation, such as tumors with NRAS or NF-1 alterations (NRASMut, NF-1LOF), as well as for patients with MAPK pathway inhibitor-resistant BRAFMut melanomas, which commonly exhibit a reactivation of this pathway. p90 ribosomal S6 kinases (RSKs) represent central effectors of MAPK signaling, regulating cell cycle progression and survival.
Methods
RSK activity and the functional effects of its inhibition by specific small molecule inhibitors were investigated in established melanoma cell lines and patient-derived short-term cultures from different MAPK pathway-hyperactivated genomic subgroups (NRASMut, BRAFMut, NF-1LOF). Real-time qPCR, immunoblots and flow cytometric cell surface staining were used to explore the molecular changes following RSK inhibition. The effect on melanoma cell growth was evaluated by various two- and three-dimensional in vitro assays as well as with melanoma xenograft mouse models. Co-cultures with gp100- or Melan-A-specific cytotoxic T cells were used to assess immunogenicity of melanoma cells and associated T-cell responses.
Results
In line with elevated activity of the MAPK/RSK signaling axis, growth and survival of not only BRAFMut but also NRASMut and NF-1LOF melanoma cells were significantly impaired by RSK inhibitors. Intriguingly, RSK inhibition was particularly effective in three-dimensional growth settings with long-term chronic drug exposure and suppressed tumor cell growth of in vivo melanoma models. Additionally, our study revealed that RSK inhibition simultaneously promoted differentiation and immunogenicity of the tumor cells leading to enhanced T-cell activation and melanoma cell killing.
Conclusions
Collectively, RSK inhibitors exhibited both multi-layered anti-tumor efficacy and broad applicability across different genomic melanoma subgroups. RSK inhibition may therefore represent a promising novel therapeutic strategy for malignant melanoma with hyperactivated MAPK signaling.
Funder
Deutsche Krebshilfe
Medizinischen Fakultät, Eberhard Karls Universität Tübingen
Hiege-Stiftung gegen Hautkrebs
Deutsche Forschungsgemeinschaft
Westfälische Wilhelms-Universität Münster
Universitätsklinikum Münster
Publisher
Springer Science and Business Media LLC
Reference48 articles.
1. Wellbrock C, Arozarena I. The Complexity of the ERK/MAP-Kinase Pathway and the Treatment of Melanoma Skin Cancer. Front Cell Dev Biol. 2016;4:33.
2. Cohen C, Zavala-Pompa A, Sequeira JH, Shoji M, Sexton DG, Cotsonis G, et al. Mitogen-actived protein kinase activation is an early event in melanoma progression. Clin Cancer Res. 2002;8(12):3728–33.
3. Davies H, Bignell GR, Cox C, Stephens P, Edkins S, Clegg S, et al. Mutations of the BRAF gene in human cancer. Nature. 2002;417(6892):949–54.
4. Cancer Genome Atlas N. Genomic Classification of Cutaneous Melanoma. Cell. 2015;161(7):1681–96.
5. Hayward NK, Wilmott JS, Waddell N, Johansson PA, Field MA, Nones K, et al. Whole-genome landscapes of major melanoma subtypes. Nature. 2017;545(7653):175–80.
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献