自噬是真核细胞中一种高度保守的细胞生物学行为,是细胞内包裹细胞质成分的双层膜结构形成并与溶酶体结合产生自我吞噬性质的一种分解代谢过程。自噬的分解代谢作用可以清除细胞内的毒性物质,维持细胞内环境稳态,同时在这一过程中产生的氨基酸等小分子物质可被细胞代谢循环利用,为细胞的生存提供营养。自噬维持细胞内环境稳态的作用能抑制肿瘤的发生;但在已完成恶性转化的肿瘤细胞中,自噬能在不利于肿瘤生存的微环境内维持肿瘤细胞的基础代谢,保持细胞活性。在恶性肿瘤的增殖和侵袭转移过程中,自噬能调节肿瘤细胞的微环境,抑制细胞失巢凋亡,参与细胞休眠和上皮—间充质转化等一系列过程,从而发挥重要作用。
Autophagy is a highly conservative biological behavior in eukaryotic cells. This dynamic process involves “wrapping” cytoplasmic components and combining with lysosomes in cells for catabolism. The catabolic effect of autophagy can eliminate toxic substances in cells, maintain homeostasis in the intracellular environment, and produce small molecules, such as amino acids, which nourish cells, thereby allowing them to survive. Autophagy can inhibit the occurrence of tumors by maintaining homeostasis in the intracellular environment. However, it can promote the proliferation, invasion, and metas- tasis of malignant tumor cells. Autophagy can regulate the microenvironment of tumor cells and has an important role in a series of processes, such as anoikis, tumor dormancy, and epithelial-mesenchymal transition.