Abstract A113: Chronic stress promotes lymph node metastasis through beta-adrenergic regulation of lymphangiogenesis

Lymphangiogenesis drives breast cancer metastasis to lymph nodes. However, the physiological pathways that regulate lymphangiogenesis and lymph node metastasis are yet to be defined. We have previously shown that chronic stress increased metastasis of primary tumour cells to lymph nodes via beta-adrenergic receptor signaling. Consistent with a critical role for beta-adrenergic signaling in cancer progression, recent clinical studies found that blockade of beta-adrenergic activation protected women with triple negative breast cancer from distant metastasis.

To investigate if the beta-adrenergic pathway promotes metastasis by impacting lymphangiogenesis, we explored the effect of restraint stress or pharmacological activation of beta-adrenergic pathways in an orthotopic xenograft model of triple negative breast cancer. To physiologically activate beta-adrenergic signaling, mice were subjected to 2 hours of daily restraint for 7 days prior to tumor cell inoculation and 14 days thereafter. Serial bioluminescence imaging revealed chronic stress reduced time to lymph node metastasis and increased tumor cell load in draining lymph nodes. Stress increased the expression of lymphangiogenic factor VEGF-C and its receptor Vefgr-3 and increased lymphangiogenesis within primary tumors. Pharmacological activation of beta-adrenergic signaling with isoproterenol similarly increased lymphangiogenesis and metastasis.

Prostaglandin-mediated dilation of lymphatic collector vessels was recently linked to increased breast cancer metastasis. We found stress increased expression of COX-2, the rate limiting enzyme in prostaglandin production, and increased dilation of lymphatic vessels that link primary tumors to draining lymph nodes. Treatment with COX-2 inhibitor celecoxib reversed stress-induced lymph vessel dilation and similarly blocked stress-enhanced lymph node metastasis and tumor lymphangiogenesis.

Together, these data show that beta-adrenergic receptor signalling may be an important effector pathway of stress-enhanced lymphangiogenesis and LN metastasis and that beta-blockade of lymphangiogenesis may be an important mechanism in protecting women with breast cancer from the adverse effects of stress biology.

Citation Format: Caroline P. Le, Matthew A. Pimentel, Corina Kim, Cameron J. Nowell, Tara Karnezis, Ming G. Chai, Marco Herald, Steven A. Stacker, Erica K. Sloan. Chronic stress promotes lymph node metastasis through beta-adrenergic regulation of lymphangiogenesis. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A113.