Our previous study showed that the abscisic acid receptor lanthionine synthetase C-like 2 (LanCL2) is a significant prognostic factor for overall survival in young glioblastoma patients. However, the role of LanCL2 in glioblastoma remains unclear yet. This study aims to investigate the role of LanCL2 in regulating cell invasion and tumor progression of glioblastoma and its underlying mechanism. Tyrosine 198 or 295 residue of LanCL2 was mutated using site-directed mutagenesis to block its phosphorylation. The role of LanCL2 in glioblastoma was investigated using transwell or 3D invasion assay, matrix degradation assay and intracranial xenograft model. This study showed that nuclear transport of LanCL2 was enhanced by overexpression of LanCL2 or its ligand abscisic acid in glioblastoma cells. Knockdown of LanCL2 suppressed migration, invasion and invadopodia formation of glioblastoma cells, whereas overexpression of wild-type LanCL2 enhanced them. Blocking of Tyr295 residue phosphorylation of LanCL2 impeded its nuclear transport, retarded glioblastoma cell motility and invadopodia formation, and deceased the phosphorylation of Cortactin and STAT3. c-Met was identified as the upstream tyrosine kinase of Tyr295 residue of LanCL2, and inhibition of c-Met markedly suppressed the nuclear transport of LanCL2. Moreover, overexpression of wild-type LanCL2 significantly promoted orthotopic tumor growth of glioblastoma and led to poor survival of mice with median survival time of 33.5 days, whereas Tyr295 mutation rescued it with median survival time of 49 days. Our findings suggested that Tyr295 phosphorylation is crucial to the activation and nuclear transport of LanCL2, as well as invadopodia formation and tumor progression of glioblastoma, providing the evidence of a novel signaling axis c-Met/LanCL2/STAT3/Cortactin and the first observation of the importance of Tyr295 phosphorylation to LanCL2.

中文翻译：

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磷酸化 LanCL2 的核转运通过激活 STAT3/Cortactin 信号促进胶质母细胞瘤的侵袭伪足形成和肿瘤进展

我们之前的研究表明，脱落酸受体羊毛硫氨酸合成酶 C 样 2 (LanCL2) 是年轻胶质母细胞瘤患者总体生存的重要预后因素。然而，LanCL2 在胶质母细胞瘤中的作用仍不清楚。本研究旨在探讨LanCL2在调节胶质母细胞瘤细胞侵袭和肿瘤进展中的作用及其潜在机制。使用定点诱变对 LanCL2 的酪氨酸 198 或 295 残基进行突变以阻断其磷酸化。使用 Transwell 或 3D 侵袭测定、基质降​​解测定和颅内异种移植模型研究 LanCL2 在胶质母细胞瘤中的作用。这项研究表明，在胶质母细胞瘤细胞中过表达 LanCL2 或其配体脱落酸可以增强 LanCL2 的核转运。 LanCL2 的敲低抑制了胶质母细胞瘤细胞的迁移、侵袭和侵袭伪足的形成，而野生型 LanCL2 的过表达则增强了它们。阻断 LanCL2 的 Tyr295 残基磷酸化会阻碍其核运输，延迟胶质母细胞瘤细胞运动和侵袭伪足的形成，并减少 Cortactin 和 STAT3 的磷酸化。 c-Met被鉴定为LanCL2的Tyr295残基的上游酪氨酸激酶，抑制c-Met可显着抑制LanCL2的核转运。此外，野生型LanCL2的过表达显着促进胶质母细胞瘤的原位肿瘤生长，并导致小鼠存活率低，中位生存时间为33.5天，而Tyr295突变则挽救了小鼠，中位生存时间为49天。我们的研究结果表明，Tyr295 磷酸化对于 LanCL2 的激活和核运输以及胶质母细胞瘤的侵袭伪足形成和肿瘤进展至关重要，这为新的信号轴 c-Met/LanCL2/STAT3/Cortactin 的存在提供了证据，并首次观察到Tyr295 磷酸化对 LanCL2 的重要性。