To explore the relationship between autophagy and cell function, we investigated how PLAC8‐mediated autophagy influences proliferation, apoptosis and epithelial‐mesenchymal transition (EMT) in NPC. Colony formation analyses and CCK8 assays were used to assess the proliferative capacity of NPC cells. Transmission electron microscopy (TEM) was used to identify autophagosomes. Autophagic flux was monitored using the tandem monomeric RFP‐GFP‐tagged LC3 (tfLC3) assay. The rate of apoptosis in NPC cells was analysed by flow cytometry. Western blot analysis was used to evaluate the activation of autophagy and the signalling status of the AKT/mTOR pathway. Our study reveals that knocking out PLAC8 (koPLAC8) induces autophagy and apoptosis, while suppressing NPC cell proliferation and EMT. However, inhibition of autophagy with 3‐methyladenine or by knocking down Beclin‐1 reverses the cell proliferation, apoptosis and EMT influenced by koPLAC8. We find that koPLAC8 inhibits the phosphorylation of AKT and its downstream target, mTOR. Moreover, immunofluorescence and co‐immunoprecipitation reveal complete PLAC8/AKT colocalization and PLAC8/AKT interaction, respectively. Furthermore, knockout of PLAC8 induced autophagy and inactivated AKT/mTOR signalling pathway of NPC xenografts. Overall, our findings demonstrate that koPLAC8 induces autophagy via the AKT/mTOR pathway, thereby inhibiting cell proliferation and EMT, and promoting apoptosis in NPC cells.

中文翻译：

---

Plac8介导的自噬通过AKT / mTOR途径调节鼻咽癌细胞的功能。

为了探讨自噬与细胞功能之间的关系，我们研究了PLAC8介导的自噬如何影响NPC的增殖，凋亡和上皮间质转化（EMT）。集落形成分析和CCK8测定用于评估NPC细胞的增殖能力。透射电子显微镜（TEM）用于鉴定自噬体。使用串联单体RFP‐GFP标记的LC3（tfLC3）分析监测自噬通量。通过流式细胞仪分析NPC细胞的凋亡率。Western印迹分析用于评估自噬的激活和AKT / mTOR通路的信号传导状态。我们的研究表明，敲除PLAC8（koPLAC8）会诱导自噬和凋亡，同时抑制NPC细胞增殖和EMT。然而，用3-甲基腺嘌呤或敲除Beclin-1抑制自噬可逆转受koPLAC8影响的细胞增殖，凋亡和EMT。我们发现koPLAC8抑制AKT及其下游靶标mTOR的磷酸化。此外，免疫荧光法和共免疫沉淀法分别揭示了PLAC8 / AKT共定位和PLAC8 / AKT相互作用。此外，敲除PLAC8诱导自噬和NPC异种移植物的AKT / mTOR信号通路失活。总的来说，我们的发现表明koPLAC8通过AKT / mTOR途径诱导自噬，从而抑制细胞增殖和EMT，并促进NPC细胞凋亡。免疫荧光法和共免疫沉淀法分别显示了PLAC8 / AKT共定位和PLAC8 / AKT相互作用。此外，敲除PLAC8诱导自噬和NPC异种移植物的AKT / mTOR信号通路失活。总的来说，我们的发现表明koPLAC8通过AKT / mTOR途径诱导自噬，从而抑制细胞增殖和EMT，并促进NPC细胞凋亡。免疫荧光法和共免疫沉淀法分别显示了PLAC8 / AKT共定位和PLAC8 / AKT相互作用。此外，敲除PLAC8诱导自噬和NPC异种移植物的AKT / mTOR信号通路失活。总的来说，我们的发现表明koPLAC8通过AKT / mTOR途径诱导自噬，从而抑制细胞增殖和EMT，并促进NPC细胞凋亡。