In patients with cancer, the functionality of Dendritic Cells (DC) is hampered by high levels of tumor-derived suppressive cytokines, which interfere with DC development and maturation. Poor DC development can limit the efficacy of immune checkpoint blockade and in vivo vaccination approaches. Interference in intracellular signaling cascades downstream from the receptors of major tumor-associated suppressive cytokines like IL-10 and IL-6, might improve DC development and activation, and thus enhance immunotherapy efficacy. We performed exploratory functional screens on arrays consisting of >1000 human kinase peptide substrates to identify pathways involved in DC development and its inhibition by IL-10 or IL-6. The resulting alterations in phosphorylation of the kinome substrate profile pointed to glycogen-synthase kinase-3β (GSK3β) as a pivotal kinase in both DC development and suppression. GSK3β inhibition blocked human DC differentiation in vitro, which was accompanied by decreased levels of IL-12p70 secretion, and a reduced capacity for T cell priming. More importantly, adenoviral transduction of monocytes with a constitutively active form of GSK3β induced resistance to the suppressive effects of IL-10 and melanoma-derived supernatants alike, resulting in improved DC development, accompanied by up-regulation of co-stimulatory markers, an increase in CD83 expression levels in mature DC, and diminished release of IL-10. Moreover, adenovirus-mediated intratumoral manipulation of this pathway in an in vivo melanoma model resulted in DC activation and recruitment, and in improved immune surveillance and tumor control. We propose the induction of constitutive GSK3β activity as a novel therapeutic means to bolster DC functionality in the tumor microenvironment.

中文翻译：

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组成性活性GSK3β可以在面对肿瘤介导的免疫抑制时增强树突状细胞的功能。

在患有癌症的患者中，树突状细胞（DC）的功能会受到高水平的肿瘤抑制性细胞因子的阻碍，从而干扰DC的发展和成熟。DC发育不良会限制免疫检查点封锁和体内疫苗接种方法的功效。对主要肿瘤相关抑制性细胞因子（如IL-10和IL-6）受体下游的细胞内信号传导的干扰可能会改善DC的发育和激活，从而增强免疫疗法的效力。我们对包含> 1000种人类激酶肽底物的阵列进行了探索性功能筛选，以鉴定参与DC发育及其被IL-10或IL-6抑制的途径。所得的激酶组底物谱的磷酸化改变表明糖原合酶激酶3β（GSK3β）是DC发育和抑制中的关键激酶。GSK3β的抑制作用在体外阻断了人DC的分化，并伴随着IL-12p70分泌水平的降低和T细胞启动能力的降低。更重要的是，具有GSK3β组成型活性形式的单核细胞的腺病毒转导可诱导对IL-10和黑色素瘤来源的上清液的抑制作用产生抗性，从而导致DC发育改善，并伴随共刺激标记的上调，增加CD83在成熟DC中的表达水平，并减少IL-10的释放。此外，腺病毒介导的体内黑色素瘤模型中该途径的肿瘤内操作导致DC激活和募集，并改善了免疫监视和肿瘤控制。我们提议诱导组成型GSK3β活性作为一种新的治疗手段，以增强肿瘤微环境中的DC功能。