Enhance Mitochondrial Damage by Nuclear Export Inhibition to Suppress Tumor Growth and Metastasis with Increased Antitumor Properties of Macrophages

Mitochondria-targeting damage has become a popular therapeutic option for tumor metastasis; however, its efficacy is limited by the adaptive rescue capacity of nuclei. There is an urgent need for a dual mitochondrial and nuclear targeting strategy that can also increase the antitumor capacity of macrophages. In this study, XPO1 inhibitor KPT-330 nanoparticles were combined with mitochondria-targeting lonidamine (TPP-LND) nanoparticles. The combination of nanoparticles with a 1:4 ratio of KPT and TL demonstrated the best synergistic effect in restraining the proliferation and metastasis of 4T1 breast cancer cells. Investigating the mechanisms both in vitro and in vivo, it was found that KPT nanoparticles not only directly impede tumor growth and metastasis by controlling the expression of associated proteins but also indirectly facilitate mitochondrial damage. The two nanoparticles synergistically decreased the expression of cytoprotective factors, such as Mcl-1 and Survivin, causing mitochondrial dysfunction and thus inducing apoptosis. Additionally, it downregulated metastasis-related proteins like HIF-1α, vascular endothelial growth factor (VEGF), and matrix metalloproteinase 2 (MMP-2) and reduced endothelial-to-mesenchymal transition. Significantly, their combination increased the ratio of M1 tumor-associated macrophages (TAMs)/M2 TAMs both in vitro and in vivo and increased the phagocytosis of tumor cells by macrophages, thus suppressing tumor growth and metastasis. In summary, this research revealed that nuclear export inhibition can synergistically enhance the prevention of mitochondrial damage to tumor cells, heightening the antitumor properties of TAMs, thereby providing a viable and safe therapeutic approach for the treatment of tumor metastasis.