GILO Institute, GILO Foundation, Seoul, 06668, Republic of Korea.
Interdisciplinary Program in Cancer Biology, Seoul National University, Gwanak-gu, Seoul, 08826, Republic of Korea.
Cell Death Dis. 2023 Aug 23;14(8):546. doi: 10.1038/s41419-023-06083-6.
KIAA1324 is a transmembrane protein largely reported as a tumor suppressor and favorable prognosis marker in various cancers, including gastric cancer. In this study, we report the role of N-linked glycosylation in KIAA1324 as a functional post-translational modification (PTM). Loss of N-linked glycosylation eliminated the potential of KIAA1324 to suppress cancer cell proliferation and migration. Furthermore, we demonstrated that KIAA1324 undergoes fucosylation, a modification of the N-glycan mediated by fucosyltransferase, and inhibition of fucosylation also significantly suppressed KIAA1324-induced cell growth inhibition and apoptosis of gastric cancer cells. In addition, KIAA1324-mediated apoptosis and tumor regression were inhibited by the loss of N-linked glycosylation. RNA sequencing (RNAseq) analysis revealed that genes most relevant to the apoptosis and cell cycle arrest pathways were modulated by KIAA1324 with the N-linked glycosylation, and Gene Regulatory Network (GRN) analysis suggested novel targets of KIAA1324 for anti-tumor effects in the transcription level. The N-linked glycosylation blockade decreased protein stability through rapid proteasomal degradation. The non-glycosylated mutant also showed altered localization and lost apoptotic activity that inhibits the interaction between GRP78 and caspase 7. These data demonstrate that N-linked glycosylation of KIAA1324 is essential for the suppressive role of KIAA1324 protein in gastric cancer progression and indicates that KIAA1324 may have anti-tumor effects by targeting cancer-related genes with N-linked glycosylation. In conclusion, our study suggests the PTM of KIAA1324 including N-linked glycosylation and fucosylation is a necessary factor to consider for cancer prognosis and therapy improvement.
KIAA1324 是一种跨膜蛋白，在各种癌症中，包括胃癌，被广泛报道为肿瘤抑制因子和预后良好的标志物。在本研究中，我们报告了 KIAA1324 的 N 连接糖基化作为一种功能性翻译后修饰 (PTM) 的作用。N 连接糖基化的缺失消除了 KIAA1324 抑制癌细胞增殖和迁移的潜力。此外，我们证明了 KIAA1324 经历了岩藻糖基化，这是一种由岩藻糖基转移酶介导的 N-糖基化修饰，并且抑制岩藻糖基化也显著抑制了 KIAA1324 诱导的胃癌细胞生长抑制和凋亡。此外，KIAA1324 介导的凋亡和肿瘤消退被 N 连接糖基化的缺失所抑制。RNA 测序 (RNAseq) 分析表明，与凋亡和细胞周期阻滞途径最相关的基因被 KIAA1324 通过 N 连接糖基化调节，基因调控网络 (GRN) 分析表明 KIAA1324 在转录水平上具有抗肿瘤作用的新靶点。N 连接糖基化阻断通过快速的蛋白酶体降解降低蛋白质稳定性。非糖基化突变体也显示出改变的定位，并失去了抑制 GRP78 和 caspase 7 之间相互作用的凋亡活性。这些数据表明，KIAA1324 的 N 连接糖基化对于 KIAA1324 蛋白在胃癌进展中的抑制作用是必不可少的，并表明 KIAA1324 可能通过靶向具有 N 连接糖基化的癌症相关基因发挥抗肿瘤作用。总之，我们的研究表明，包括 N 连接糖基化和岩藻糖基化在内的 KIAA1324 的 PTM 是考虑癌症预后和治疗改善的必要因素。
