NK 细胞活化特征将 Cyclin B1/CDK1 鉴定为可成药靶点，以克服黑色素瘤中的 NK 细胞功能障碍和肿瘤侵袭性

Background/Objectives: Natural killer (NK) cells play a crucial role in immune surveillance against melanoma, yet they frequently exhibit dysfunction in the tumor microenvironment.

This study aims to establish an NK cell activation-related prognostic signature and identify potential druggable targets to overcome NK cell dysfunction. Methods : A prognostic signature was developed using the TCGA-SKCM cohort and validated across independent datasets. NK cell activation and cytotoxicity were evaluated in melanoma-NK-92MI co-culture systems via flow cytometry. Mechanistic studies employed Western blotting, co-immunoprecipitation, ELISA, and qRT-PCR. Single-cell RNA-seq data were used to analyze cell-cell communication.

Results : A four-gene NK cell activation signature was identified and validated for prognostic significance across five independent melanoma datasets. Among the identified genes, cyclin B1 (CCNB1) emerged as a novel therapeutic target for overcoming NK cell resistance.

In vivo, pharmacological inhibition of the CCNB1/Cyclin-dependent kinase 1 (CDK1) complex with RO-3306 significantly suppressed melanoma growth by enhancing NK cell infiltration and IFN-γ production. In vitro, CCNB1 knockdown in melanoma cells augmented NK-92MI activation, as evidenced by increased expression of CD69, CD107a, IFN-γ, and NKG2D, thereby improving NK cell-mediated cytotoxicity.

Mechanistically, in melanoma cells, the CCNB1/CDK1 complex phosphorylates STAT3, activating the IL-6/STAT3 positive feedback loop, which upregulates PD-L1 and enables resistance to NK cell-mediated cytotoxicity.

Beyond its role in immune evasion, CCNB1 also promoted melanoma invasiveness by inducing epithelial-mesenchymal transition (EMT) through the TGF-β-SMAD2/3 signaling. Conclusions : This study establishes CCNB1/CDK1 as a novel immunotherapeutic target and uncovers a new role for CDK1 inhibitors in enhancing NK cell function and suppressing melanoma progression.