Background: The c-MET signaling pathway is crucial for the self-renewal and tumorigenic capacity of cancer stem cells, including glioblastoma stem cells (GSCs). Despite its recognized importance, the precise mechanisms of c-MET activation in these cells remain elusive. This study aimed to elucidate the key regulatory elements and mechanisms governing c-MET function in GSCs.

Methods: The mediation of S-palmitoylation and dimerization of c-MET by zDHHC15 was validated using metabolic labeling, acyl-PEG exchange (APE), BS3 crosslinking, and co-immunoprecipitation. The role of the CK2α-zDHHC15-c-MET axis in tumorigenesis, along with the anti-tumor efficacy of TVB-3166, was confirmed through cell proliferation, limiting dilution, and intracranial tumor growth assays.

Results: We revealed that zDHHC15, a member of the DHHC family of palmitoyl acyltransferases, mediates the palmitoylation of c-MET at Cys801, which is critical for c-MET O-glycosylation, dimerization, and activation. We further identified a novel regulatory loop in which CK2α phosphorylates zDHHC15 at Tyr92, increasing its stability and c-MET binding, thereby enhancing c-MET palmitoylation. zDHHC15 was found to be specifically enriched in GSCs, and its targeted knockdown markedly impaired their self-renewal and tumorigenic capabilities both in vitro and in vivo. Therapeutically, we introduced TVB-3166, an inhibitor of c-MET S-palmitoylation, which demonstrated robust inhibitory effects on GSC growth in orthotopic xenograft models.

Conclusions: This study establishes the CK2α-zDHHC15-c-MET axis as a pivotal regulatory hub in GSC maintenance and identifies c-MET S-palmitoylation as a novel and promising therapeutic target for the treatment of glioblastoma.

Keywords: CK2α; S-palmitoylation; c-MET; glioblastoma stem cells; zDHHC15.

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背景： c-MET信号通路对于癌干细胞（包括胶质母细胞瘤干细胞 (GSCs)）的自我更新和致瘤能力至关重要。尽管其重要性已被广泛认识，但这些细胞中c-MET激活的确切机制仍然不明确。本研究旨在阐明调控GSCs中c-MET功能的关键调节元件和机制。

方法： 通过代谢标记、酰基-PEG交换 (APE) 、BS3交联及共免疫沉淀验证了zDHHC15介导的c-MET S-棕榈酰化和二聚化的调控。并通过细胞增殖试验、限制性稀释法以及颅内肿瘤生长试验，确认了CK2α-zDHHC15-c-MET轴在致瘤过程中的作用及其抗肿瘤疗效。

结果： 我们发现，作为DHHC家族棕榈酰化酶成员之一的zDHHC15，在c-MET Cys801位点介导了其棕榈酰化，这对于c-MET O-糖基化、二聚化及激活至关重要。进一步研究揭示了一个新的调控环路：CK2α在Tyr92磷酸化zDHHC15，从而提高它的稳定性和与c-MET的结合能力，进而增强c-MET棕榈酰化。我们还发现，zDHHC15在GSCs中特异性富集，其靶向敲低明显削弱了细胞体内外自我更新和致瘤的能力。从治疗角度来看，我们引入了一种针对c-MET S-棕榈酰化的抑制剂TVB-3166，在原位异种移植模型中表现出强烈的抑制GSC生长的效果。

结论： 本研究确立了CK2α-zDHHC15-c-MET轴在GSC维持中的关键调节枢纽，并且将c-MET S-棕榈酰化确认为治疗胶质母细胞瘤的新颖而有前景的治疗靶点。

关键词： CK2α；S-棕榈酰化；c-MET；胶质母细胞瘤干细胞；zDHHC15.