A brain-tumor neural circuit controls breast cancer progression in mice

Tumor burden, considered a common chronic stressor, can cause widespread anxiety. Evidence suggests that cancer-induced anxiety can promote tumor progression, but the underlying neural mechanism remains unclear. Here, we used neuroscience and cancer tools to investigate how the brain contributes to tumor progression via nerve-tumor crosstalk in mice model of breast cancer. We showed that the tumor-bearing mice exhibited significant anxiety-like behaviors and that corticotropin-releasing hormone (CRH) neurons in the central medial amygdala (CeM) were activated. Moreover, newly formed sympathetic nerves were detected in tumors, which established a polysynaptically connected with the brain. Pharmacogenetic or optogenetic inhibition of CeMCRH neurons and CeMCRH→LPGi circuit significantly alleviated anxiety-like behaviors and slowed tumor growth. Conversely, artificial activation of CeMCRH neurons and CeMCRH→LPGi circuit increased anxiety and tumor growth. Importantly, alprazolam, an anti-anxiety drug, was found to be a promising intervention for slowing tumor progression. Furthermore, we showed that manipulation of CeMCRH→LPGi circuit directly regulates the activity of the intratumoral sympathetic nerves and peripheral nerve-derived norepinephrine, then affecting tumor progression by modulating the antitumor immunity. Together, these findings reveal a brain–tumor neural circuit contributing to breast cancer progression and provide new therapeutic insights for breast cancer.