目的·探究干扰素基因刺激因子（stimulator of interferon genes，STING）信号通路缺陷型黑色素瘤中，联用磷脂酰肌醇激酶FYVE型锌指结构域蛋白（phosphoinositide 3-kinase，FYVE-type zinc finger containing，PIKfyve）抑制剂YM201636与STING激动剂diABZI的抗肿瘤效果及潜在机制。方法·分别从CCLE（Cancer Cell Line Encyclopedia）数据库和UniProt数据库获取人类肿瘤细胞系中STING的mRNA表达水平和蛋白表达水平数据，并进一步根据表达水平的中位数鉴定出STING mRNA高表达、蛋白低表达的黑色素瘤细胞。通过实时荧光定量PCR（quantitative real-time PCR，qRT-PCR）和Western blotting验证人类黑色素瘤细胞中STING的表达水平。进一步使用Western blotting筛选出STING蛋白表达较低的鼠源黑色素瘤细胞YUMM1.7，并检验YM201636能否恢复YUMM1.7的STING蛋白水平。联合应用YM201636和STING激动剂diABZI，采用CCK-8法分析双药协同的肿瘤细胞杀伤效果，Western blotting检测STING下游信号分子TANK结合激酶1（TANK-binding kinase 1，TBK1）和干扰素调节因子3（interferon regulatory factor 3，IRF3）的磷酸化水平，qRT-PCR评估Ⅰ型干扰素的表达。建立小鼠黑色素瘤模型，进行YM201636和diABZI的单药或联合治疗，测量肿瘤体积并评估治疗效果。通过RNA测序和免疫荧光染色分析小鼠肿瘤组织肿瘤微环境中免疫细胞的变化。结果·数据库分析、qRT-PCR和Western blotting证实人类黑色素瘤中部分细胞系存在STING mRNA高表达、蛋白低表达的现象。YM201636显著提高了STING蛋白在YUMM1.7细胞中的表达（P<0.001），并且在联合diABZI使用时，显著增强TBK1和IRF3蛋白的磷酸化（P<0.05），提示STING通路被有效激活。同时，YM201636和diABZI联合处理显著促进Ⅰ型干扰素的产生（P<0.001），并且显著增强肿瘤细胞的生长抑制作用。在小鼠体内实验中，与单独治疗相比，YM201636和diABZI的联合治疗能显著抑制黑色素瘤的生长。肿瘤微环境的免疫特征分析显示，联合治疗组中CD4⁺ T细胞和CD8⁺ T细胞的浸润显著增多（P<0.05）。结论·联用PIKfyve抑制剂YM201636能在STING缺陷型黑色素瘤中恢复STING蛋白的表达，增强STING激动剂diABZI的抗肿瘤效果。

Objective ·To explore the antitumor effects and potential mechanisms of combining phosphoinositide 3-kinase, FYVE-type zinc finger containing (PIKfyve) inhibitor YM201636 with the stimulator of interferon genes (STING) agonist diABZI in STINGpathway-deficient melanoma. Methods ·The mRNA and protein expression levels of STING in human cancer cell lines were obtained from the Cancer Cell Line Encyclopedia (CCLE) and UniProt databases. Based on median expression values, melanoma cell lines with high STING mRNA but low protein expression were identified. Quantitative real-time PCR (qRT-PCR) and Western blotting were performed to validate STING mRNA and protein expression in human melanoma cells. The murine melanoma cell line YUMM1.7, characterized by low STING protein expression, was selected through Western blotting. The ability of YM201636 to restore STING protein expression in YUMM1.7 cells was evaluated. STING agonist diABZI was then applied in combination with YM201636 to analyze the synergistic tumor cell-killing effect through CCK-8 assay. Western blotting was used to detect the phosphorylation of TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3), and qRT-PCR was used to evaluate type Ⅰ interferon expression. A mouse melanoma model was established and treated with YM201636, diABZI, or their combination. Tumor volume was measured, and treatment efficacy was assessed. RNA sequencing and immunofluorescence staining were performed to analyze immune cell infiltration in the tumor microenvironment. Results ·Database analyses, qRT-PCR, and Western blotting confirmed that some human melanoma cell lines exhibited high STING mRNA expression but low STING protein levels. YM201636 significantly increased STING protein expression in YUMM1.7 cells (P<0.001). Combined treatment with YM201636 and diABZI significantly enhanced phosphorylation of TBK1 and IRF3 (P<0.05), indicating effective activation of the STING signaling pathway. This combination also promoted the expression of type Ⅰ interferons (P<0.001) and enhanced tumor cell killing in vitro. In vivo, the combination therapy markedly suppressed melanoma growth compared to monotherapy. Immune profiling of the tumor microenvironment revealed significantly increased infiltration of CD4⁺ T cells and CD8⁺ T cells in the combination treatment group (P<0.05). Conclusion ·The PIKfyve inhibitor YM201636 could restore STING protein expression in STING-deficient melanoma and enhance the antitumor efficacy of the STING agonist diABZI, offering a promising therapeutic strategy for tumors with defective STING signaling.