IL-36γ drives skin toxicity induced by EGFR/MEK inhibition and commensal Cutibacterium acnes
Takashi K. Satoh, Mark Mellett, Barbara Meier-Schiesser, Gabriele Fenini, Atsushi Otsuka, Hans-Dietmar Beer, Tamara Rordorf, Julia-Tatjana Maul, Jürg Hafner, Alexander A. Navarini, Emmanuel Contassot, Lars E. French
Takashi K. Satoh, Mark Mellett, Barbara Meier-Schiesser, Gabriele Fenini, Atsushi Otsuka, Hans-Dietmar Beer, Tamara Rordorf, Julia-Tatjana Maul, Jürg Hafner, Alexander A. Navarini, Emmanuel Contassot, Lars E. French
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Research Article Dermatology Inflammation

IL-36γ drives skin toxicity induced by EGFR/MEK inhibition and commensal Cutibacterium acnes

Abstract

Epidermal growth factor receptor (EGFR) and MEK inhibitors (EGFRi/MEKi) are beneficial for the treatment of solid cancers but are frequently associated with severe therapy-limiting acneiform skin toxicities. The underlying molecular mechanisms are poorly understood. Using gene expression profiling we identified IL-36γ and IL-8 as candidate drivers of EGFRi/MEKi skin toxicity. We provide molecular and translational evidence that EGFRi/MEKi in concert with the skin commensal bacterium Cutibacterium acnes act synergistically to induce IL-36γ in keratinocytes and subsequently IL-8, leading to cutaneous neutrophilia. IL-36γ expression was the combined result of C. acnes–induced NF-κB activation and EGFRi/MEKi–mediated expression of the transcription factor Krüppel-like factor 4 (KLF4), due to the presence of both NF-κB and KLF4 binding sites in the human IL-36γ gene promoter. EGFRi/MEKi increased KLF4 expression by blockade of the EGFR/MEK/ERK pathway. These results provide an insight into understanding the pathological mechanism of the acneiform skin toxicities induced by EGFRi/MEKi and identify IL-36γ and the transcription factor KLF4 as potential therapeutic targets.

Authors

Takashi K. Satoh, Mark Mellett, Barbara Meier-Schiesser, Gabriele Fenini, Atsushi Otsuka, Hans-Dietmar Beer, Tamara Rordorf, Julia-Tatjana Maul, Jürg Hafner, Alexander A. Navarini, Emmanuel Contassot, Lars E. French

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Figure 4

Blockade of the EGFR/MEK/ERK pathway increases keratinocyte expression of KLF4.

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Blockade of the EGFR/MEK/ERK pathway increases keratinocyte expression o...
(A) Quantitative PCR was performed to evaluate gene expression in RNA isolated from biopsies of 4 patients with acneiform eruption and 10 healthy control (HC) skin biopsies. Data represent mean ± SD. (B) PHKs were pre-exposed to the BRAF inhibitor vemurafenib (1 μg/mL) for 30 minutes and exposed to the MEK inhibitor trametinib (2 μg/mL) and C. acnes (MOI of 10) for 6 hours. Data represent mean ± SEM (n = 3). Data were analyzed with 2-tailed unpaired t test (A) or 1-way ANOVA followed by Tukey’s multiple-comparisons test (B). *P < 0.05; **P < 0.01; ***P < 0.001. (C) PHKs were exposed to erlotinib (1 μM) or trametinib (2 μg/mL) for 24 hours and total cell lysates were collected for Western blotting with antibodies against KLF4 and β-actin. (D) ERK1 and ERK2 were silenced by siRNA in PHKs and cell lysates were analyzed by SDS-PAGE and immunoblotting with indicated antibodies. (E) HEK293T cells were transfected with FLAG-tagged KLF4 and Myc-tagged ERK1 and ERK2 for 24 hours. Cell lysates were immunoprecipitated with an anti-FLAG antibody, followed by immunoblotting with the indicated antibodies. (F) HEK293T cells were transfected with FLAG-tagged KLF4, HA-tagged ubiquitin, and constitutively active ERK (CA-ERK) for 24 hours. Cell lysates were immunoprecipitated with an anti-FLAG antibody, followed by immunoblotting with the indicated antibodies. All blots were run contemporaneously with the same protein samples. Data are representative of 3 independent experiments.