Role of the AHR pathway in UV-induced initiation and progression of melanoma and in resistance to therapy

黑色素瘤是最致命的皮肤癌类型，占全球癌症病例的近2%，由于娱乐性紫外线照射的持续趋势，发病率不断上升。芳烃受体（AHR）是碱性螺旋-环-螺旋Per-ARNT-Sim家族的一种配体结合转录因子，最初被描述为二恶英TCDD的受体，并已被证明可以介导环境污染物的解毒。最近，随着越来越多的证据表明AHR在细胞增殖、分化和炎症反应中的生理作用，大量的生理性和内源性配体被发现。紫外线已被证明产生高亲和力的AHR激动剂FICZ，促进皮肤晒黑，作为对紫外线的保护反应。然而，在癌细胞中，AHR激活促进肿瘤进展。目前的项目是基于这样的假设，即在生理环境下，AHR信号传导促进黑色素细胞对紫外线照射的保护性反应，而在病理环境下，AHR信号传导增强恶性转化和转移进展，并损害T细胞定向免疫治疗的疗效。在该项目的第一个工作包中，我们将使用黑色素细胞特异性、条件AHR敲除小鼠来表征AHR信号传导对黑色素细胞对紫外线反应的影响。此外，我们还将利用Hgf-Cdk4黑色素瘤模型与黑色素细胞特异性AHR敲除小鼠杂交，分析AHR信号在紫外线诱导的肿瘤发生和进展中的作用。在第二个工作包中，我们将评估AHR信号在免疫治疗中的作用。为此，我们将使用我们的可移植黑色素瘤细胞系HCmel12，无论是否带有CRISPR介导的AHR敲除，并进行过继性t细胞转移。此外，我们还将在移植了HCmel12黑色素瘤细胞的小鼠中结合过继细胞转移疗法和药物AHR抑制，以评估人类治疗性AHR抑制的未来前景。在第三个工作包中，我们将在体外描述黑色素细胞和黑色素瘤细胞中的AHR信号动力学。随后，我们试图分析AHR信号对炎症诱导的黑色素瘤细胞可塑性的影响，并揭示其潜在的分子机制。在最后的工作包中，我们将通过单细胞RNA测序分析AHR信号对黑色素瘤细胞转录可塑性动态的影响，以响应炎症和治疗刺激。此外，我们还将描述UVB照射后皮肤黑色素细胞和黑色素瘤细胞分化轨迹上的AHR信号。我们期望从该项目中获得的见解将为未来治疗黑色素瘤中AHR信号的治疗调节提供理论依据。

Melanoma, the most lethal type of skin cancer, accounts for almost 2% of cancer cases worldwide, with an increasing incidence due to the unbroken trend of recreational UV exposure. The aryl hydrocarbon receptor (AHR), a ligand binding transcription factor of the basic helix-loop-helix Per-ARNT-Sim family, was initially described as the receptor for the dioxin TCDD and has been shown to mediate the detoxification of environmental pollutants. More recently, a multitude of physiological and endogenous ligands have been discovered, along with increasing evidence of physiological roles of AHR in cell proliferation, differentiation and inflammatory responses. UV light has been shown to generate the high affinity AHR agonist FICZ that promotes skin tanning as a protective response against UV. However, in cancer cells AHR activation promotes tumor progression. The current project is based on the hypothesis that AHR signaling promotes protective melanocyte responses to UV irradiation in physiological settings, whereas in pathologic settings, AHR signaling enhances malignant transformation as well as metastatic progression and impairs the efficacy of T cell directed immunotherapies. In the first work package of the project, we will use melanocyte-specific, conditional AHR knockout mice to characterize the impact of AHR signaling on the response of melanocytes to UV light. Additionally, we will also analyze the role of AHR signaling on UV-induced tumor development and progression by utilizing the Hgf-Cdk4 melanoma model crossed with the melanocyte-specific AHR knockout mice. In the second work package, we will assess the role of AHR signaling on immunotherapy. For this, we will use our transplantable melanoma cell line HCmel12 with and without a CRISPR mediated AHR knockout and perform adoptive T-cell transfer. Furthermore, we will also combine adoptive cell transfer therapies with pharmacological AHR inhibition in mice transplanted with HCmel12 melanoma cells to assess the future prospect of therapeutic AHR inhibition in man. In the third work package, we will characterize the AHR signaling dynamics in melanocytes and melanoma cells in vitro. Subsequently, we attempt to analyze the impact of AHR signaling on inflammation-induced melanoma cell plasticity and unravel the underlying molecular mechanism. In the final work package, we will analyze the impact of AHR signaling on the dynamics of melanoma cell transcriptional plasticity in response to inflammatory and therapeutic stimuli via single cell RNA sequencing. Additionally, we will also characterize AHR signaling on the differentiation trajectories of cutaneous melanocytes and melanoma cells following UVB irradiation. We expect that the insights gained from this project will provide a rationale for the future therapeutic modulation of AHR signaling in the treatment of melanoma.