A study led by Weill Cornell Medicine investigators found that sympathetic nerve fibers growing into melanoma tumors can inhibit tumor growth by reducing the number of tumor-supportive macrophages.
The research, published April 29 in Neuron, used mouse models of melanoma and whole-mount immuno-labeling to examine nerve-tumor interactions.
Key Findings
- Peripheral nerves, including pain-sensitive and sympathetic nerves, were found in melanomas and increased in number as tumors grew, particularly in slower-growing tumors.
- Pain-sensitive nerves promoted tumor growth; depleting them inhibited tumor growth.
- Sympathetic nerves, which release norepinephrine, exerted an anti-tumor effect through alpha adrenergic receptors on macrophages.
- Activation of alpha adrenergic receptors reduced the numbers of pro-tumor macrophages, slowing tumor growth.
Implications
The findings suggest that the sympathetic nervous system can act as a brake on cancer growth in some contexts.
Future research may explore whether targeting these nerves or alpha adrenergic receptors on tumor-associated macrophages could inform anti-cancer therapies. Drugs targeting these receptors are already used for blood pressure treatment.
Background
The peripheral nervous system includes sensory and sympathetic nerves. Sympathetic nerves typically release norepinephrine to influence organ functions. Prior research mostly found that nerves enhance tumor growth, but this study indicates a context-dependent inhibitory role.