Lidocaine combined with general anesthetics impedes metastasis of breast cancer cells via inhibition of TGF-β/Smad-mediated EMT signaling by reprogramming tumor-associated macrophages.

Surgical resection is the best-known approach for breast cancer treatment. However, post-operative metastases increase the rate of death. The potential effect of anesthetic drugs on long-term tumor growth, risk of metastasis, and recurrence after surgery has been investigated in cancer patients. However, the underlying mechanisms remain unclear. Therefore, we aimed to elucidate the anti-metastatic effect of lidocaine combined with common anesthetics and its mechanisms of action on lung metastasis in breast cancer models. The combination of lidocaine with propofol or sevoflurane inhibited the growth of TNBC cells compared to treatment alone. In addition, the combination effectively inhibited cancer cell migration and invasion. It suppressed tumor growth and increased the survival rate in breast 4 T1 orthotopic models. More importantly, it inhibited lung metastasis and recurrence compared with groups treated with a single anesthetic. In co-culture with TAMs and TNBC cells, lidocaine not only reduced M2-tumor-associated macrophages (TAM) that were increased by sevoflurane or propofol but also increased M1 macrophage polarization, impeding tumor growth in TNBC. Also, we found that the transforming growth factor-β (TGF-β) derived from TAMs increased EMT signaling in TNBC cells, and that lidocaine affected cancer cells as well as M2-TAMs, inducing M2 to M1 reprogramming and decreasing TGF-β/Smads-mediated EMT signaling in TNBC cells, leading to inhibition of cancer metastasis and recurrence. These findings suggest lidocaine combined with general anesthetics as a potential therapeutic approach for the inhibition of recurrence and metastasis of breast cancer patients undergoing curative resection.