近期的研究表明TLK与肿瘤发展有关。然而，TLK2在胃癌（GC）中的功能和作用机制尚不清楚。本研究发现，在GC患者中TLK2显著上调，并被确定为GC的独立预后因子。一致地，TLK2敲低显著降低了GC的攻击性，而其过度表达则产生了相反的效果。IP-MS结果显示，TLK2对GC的影响主要与代谢重编程有关。TLK2敲低通过在GC细胞中下调mTORC1通路和ASNS表达来抑制氨基酸合成。在机制上，mTORC1直接与ASNS蛋白相互作用并抑制其降解。进一步的实验证明，ASNS蛋白通过泛素化而不是自噬降解。抑制和激活mTORC1通路可以升高和降低ASNS的泛素化，而mTORC1通路能够使TLK2对ASNS的调节效应逆转。此外，TLK2调节了ASNS的mRNA表达。TLK2直接与ASNS的转录因子ATF4相互作用，并促进其表达。激酶抑制剂fostamatinib通过抑制TLK2活性显著抑制了GC细胞的增殖、浸润和迁移能力。总之，本研究揭示了TLK2与mTORC1/ASNS轴之间的新的功能关系。因此，TLK2可能作为GC的潜在治疗靶点。© 2023. 作者，已独家授权给施普林格·自然美国公司。

Several recent studies have suggested that TLKs are related to tumor progression. However, the function and mechanism of action of TLK2 in gastric cancer (GC) remain elusive. In this study, TLK2 was found to be significantly upregulated in patients with GC and was identified as an independent prognostic factor for GC. Consistently, TLK2 knockdown markedly reduced the aggressiveness of GC, whereas its overexpression had the opposite effect. IP-MS revealed that the effects of TLK2 on GC were mainly associated with metabolism reprogramming. TLK2 knockdown suppressed amino acid synthesis by downregulating the mTORC1 pathway and ASNS expression in GC cells. Mechanistically, mTORC1 directly interacts with the ASNS protein and inhibits its degradation. Further experiments validated that the ASNS protein was degraded via ubiquitination instead of autophagy. Inhibiting and activating the mTORC1 pathway can upregulate and downregulate ASNS ubiquitination, respectively, and the mTORC1 pathway can reverse the regulatory effects of TLK2 on ASNS. Furthermore, TLK2 was found to regulate the mRNA expression of ASNS. TLK2 directly interacted with ATF4, a transcription factor of ASNS, and promoted its expression. The kinase inhibitor fostamatinib significantly inhibited the proliferative, invasive, and migratory capabilities of GC cells by inhibiting TLK2 activity. Altogether, this study reveals a novel functional relationship between TLK2 and the mTORC1/ASNS axis in GC. Therefore, TLK2 may serve as a potential therapeutic target for GC.© 2023. The Author(s), under exclusive licence to Springer Nature America, Inc.