Nano-pulse stimulation induces potent immune responses, eradicating local breast cancer while reducing distant metastases.

Nano-pulse stimulation (NPS) as a developing technology has been studied for minimally invasive, nonthermal local cancer elimination for more than a decade. Here we show that a single NPS treatment results in complete regression of the poorly immunogenic, metastatic 4T1-Luc mouse mammary carcinoma. Impressively, spontaneous distant organ metastases were largely prevented, even in those animals with incomplete tumor regression. All tumor-free mice were protected from secondary tumor cell challenge, demonstrating a vaccine-like effect. NPS treatment induced antitumor immunity, long-term memory T cells, destruction of tumor microenvironment and reversal of the massive increase of immune suppressor cells in the tumor microenvironment and blood. NPS-treated 4T1 cells exhibited release of damage-associated molecular patterns (DAMPs), including calreticulin, HMGB1 and ATP, and activated dendritic cells. Those findings suggest that NPS is a potent immunogenic cell death inducer that elicits antitumor immunity to prevent distant metastases in addition to local tumor eradication.