Metastasis to distant tissues is the chief driver of breast cancer-related mortality, but little is known about the systemic physiologic dynamics that regulate this process. To investigate the role of neuroendocrine activation in cancer progression, we used in vivo bioluminescence imaging to track the development of metastasis in an orthotopic mouse model of breast cancer. Stress-induced neuroendocrine activation had a negligible effect on growth of the primary tumor but induced a 30-fold increase in metastasis to distant tissues including the lymph nodes and lung. These effects were mediated by β-adrenergic signaling, which increased the infiltration of CD11b + F4/80 + macrophages into primary tumor parenchyma and thereby induced a prometastatic gene expression signature accompanied by indications of M2 macrophage differentiation. Pharmacologic activation of β-adrenergic signaling induced similar effects, and treatment of stressed animals with the β-antagonist propranolol reversed the stress-induced macrophage infiltration and inhibited tumor spread to distant tissues. The effects of stress on distant metastasis were also inhibited by in vivo macrophage suppression using the CSF-1 receptor kinase inhibitor GW2580. These findings identify activation of the sympathetic nervous system as a novel neural regulator of breast cancer metastasis and suggest new strategies for antimetastatic therapies that target the β-adrenergic induction of prometastatic gene expression in primary breast cancers.

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Construction of a complex virus may involve a hierarchy of assembly elements. Here, we report the structure of the whole human adenovirus virion at 3.6Å resolution by cryo-electron microscopy, revealing in situ atomic models of three minor capsid proteins (IIIa, VIII and IX), extensions of the major (penton base and hexon) capsid proteins, and interactions within three protein-protein networks. One network is mediated by protein IIIa within Group-of-Six (GOS) tiles – a penton base and its five surrounding hexons – at vertices. Another is mediated by ropes (protein IX) that lash hexons together to form Group-of-Nine (GON) tiles and bind GONs to GONs. The third, mediated by IIIa and VIII, binds each GOS to five surrounding GONs. Optimization of adenovirus for cancer and gene therapy could target these networks.

Radiotherapy is used to treat many types of cancer, but many treated patients relapse with local tumor recurrence. Tumor-infiltrating myeloid cells (TIMs), including CD11b (ITGAM)+F4/80 (EMR1)+ tumor-associated macrophages (TAMs) and CD11b+Gr-1 (LY6G)+ myeloid-derived suppressor cells (MDSCs), respond to cancer-related stresses and play critical roles in promoting tumor angiogenesis, tissue remodeling and immunosuppression. In this report, we employed a prostate cancer model to investigate the effects of irradiation on TAMs and MDSCs in tumor-bearing animals. Unexpectedly, when primary tumor sites were irradiated we observed a systemic increase of MDSCs in spleen, lung, lymph nodes and peripheral blood. Cytokine analysis showed that the macrophage colony-stimulating factor CSF1 increased by 2-fold in irradiated tumors. Enhanced macrophage migration induced by conditioned media from irradiated tumor cells was completely blocked by a selective inhibitor of CSF1R. These findings were confirmed in prostate cancer patients, where serum levels of CSF1 increased after radiotherapy. Mechanistic investigations revealed the recruitment of the DNA damage-induced kinase ABL1 into cell nuclei where it bound the CSF1 gene promoter and enhanced CSF1 gene transcription. When added to radiotherapy, a selective inhibitor of CSF1R suppressed tumor growth more effectively than radiation alone. Our results highlight the importance of CSF1/CSF1R signaling in the recruitment of TIMs which can limit the efficacy of radiotherapy. Further, they suggest that CSF1 inhibitors should be evaluated in clinical trials in combination with radiotherapy as a strategy to improve outcomes.