β-blocker suppresses both tumoral sympathetic neurons and perivascular macrophages during oncolytic herpes virotherapy.

BACKGROUND

The autonomic nervous system (ANS) plays a key role in regulating tumor development and therapy resistance in various solid tumors. Within the ANS, the sympathetic nervous system (SNS) is typically associated with protumor effects. However, whether the SNS influences the antitumor efficacy of intratumoral injections of oncolytic herpes simplex virus (oHSV) in solid tumors remains unknown.

METHODS

In this study, we examined SNS innervation and its interaction with immune cell infiltration in both human and murine triple-negative breast cancer models during intratumoral oHSV injections and SNS blockade on oHSV's antitumor activity.

RESULTS

Intratumor oHSV injection promotes SNS innervation accompanied by CD45+cell infiltration in both the human MDA-MB-468 orthotopic model and the murine 4T1 mammary tumor model. Mechanistically, tumor-secreted factors vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and transforming growth factor beta (TGF-β) and transcription factors (CREB, AP-1, MeCP2, and REST), which promote SNS innervation, were found to be upregulated in oHSV-treated tumors. Combining the SNS antagonist, a β-blocker, with oHSV significantly increased immune cell infiltration, particularly CD8+T cells in oHSV-treated 4T1 tumors. Single-cell messenger RNA sequencing revealed that oHSV injection upregulated a specific population of perivascular macrophages (pvMacs) expressing high levels of VEGFA, CD206, CCL3, and CCL4, which suppress T-cell activation. The use of a β-blocker reduced the infiltration of oHSV-induced pvMacs, transition to inflammatory macrophages expressing Hexb, enhancing the diversity of T-cell receptor clonotypes. Further analysis suggested that TGF-β signaling within the tumor partially mediates SNS activation in the 4T1 model.

CONCLUSION

Our findings demonstrate that combining a β-blocker with oHSV significantly enhances the antitumor efficacy of oHSV in breast cancer by targeting TGF-β-mediated SNS innervation and immunosuppression.