Intracellular organelle cross-talk is a new and important research area. Under stress conditions, the coordinated action of the autophagy and endosomal systems in tumor cells is essential for maintaining cellular homeostasis and survival. The activation of the IκB kinase (IKK) complex is also involved in the regulation of stress and homeostasis in tumor cells. Here, we try to explore the effects of constitutively active IKKβ subunits (CA-IKKβ) on autophagy and endosomal system interactions. We confirm that CA-IKKβ induces accumulation of autophagosomes and their fusion with MVBs to form amphisomes in cancer cells, and also drives the release of EVs containing autophagy components through an amphisome-dependent mechanism. We further demonstrate that CA-IKKβ inhibits the expression of RAB7, thereby weakening the lysosomal-dependent degradation pathway. CA-IKKβ also induces phosphorylation of SNAP23 at Ser95 instead of Ser110, which further promotes amphisome-plasma membrane fusion and sEV secretion. These results indicate that CA-IKKβ drives the formation and transport of amphisomes, thereby regulating tumor cell homeostasis, which may illuminate a special survival mechanism in tumor cells under stress.

细胞内细胞器串扰是一个新的重要研究领域。在应激条件下，肿瘤细胞中自噬和内体系统的协同作用对于维持细胞稳态和存活至关重要。IκB激酶（IKK）复合物的激活也参与肿瘤细胞应激和体内稳态的调节。在这里，我们尝试探索组成型活性IKKβ亚基（CA-IKKβ）对自噬和内体系统相互作用的影响。我们证实，CA-IKKβ诱导自噬体的积累及其与MVB的融合，从而在癌细胞中形成两亲体，并且还通过两亲体依赖性机制驱动含有自噬成分的EV的释放。我们进一步证明，CA-IKKβ抑制RAB7的表达，从而削弱了溶酶体依赖性降解途径。CA-IKKβ还会在Ser95而不是Ser110上诱导SNAP23的磷酸化，从而进一步促进两性质膜融合和sEV的分泌。这些结果表明，CA-IKKβ驱动了两性小体的形成和运输，从而调节了肿瘤细胞的动态平衡，这可能阐明了肿瘤细胞在压力下的特殊存活机制。