On statistical tests of functional connectome fingerprinting

Background: Surgical removal of malignancies may enhance the risk of recurrence but mechanisms remain poorly understood. Neutrophils, first line responders after surgical stress, can facilitate cancer progression. Neutrophils can expel nuclear DNA studded with proteins to form web-like structures known as Neutrophil Extracellular Traps (NETs) in response to stress. Here we aim to characterize the role of NETs in promoting metastatic cancer growth after surgical stress that is currently entirely unknown. Methods: We used a standardized mouse model of partial hepatic ischemia reperfusion, to stimulate surgical stress, directly or five days after splenic injection of MC38 colon carcinoma cells. Results: We found that NET formation is significantly increased in the immediate post-operative period in humans undergoing curative liver resection for colorectal cancer metastases. The risk of liver metastases recurrence was 4.22 times higher in patients with increased post-operative NET formation. In the murine model, we demonstrated increased NET deposition after surgical stress and this was associated with both increased formation of metastases and growth of already established micrometastatic disease. In vitro, NETs increase growth, invasion, migration and adhesion in multiple cancer cell lines. All the above effects were abrogated by NET inhibition with DNAse. NETs exert their pro-tumorigenic effects by releasing HMGB1 and activating TLR-9 dependent pathways in the cancer cells. In addition, as metastatic tumors continue to grow, hypoxia within the tumor microenvironment induces further neutrophil recruitment and NET formation that further accelerates tumor growth. Conclusions: These findings implicate NETs in the process of cancer metastasis progression and recurrence after surgery and identifies NETs as potential therapeutic targets. Citation Format: Samer Tohme, Hai Huang, Alexis Chidi, Richard Simmons, Allan Tsung. The role of neutrophil extracellular traps in promoting metastatic cancer following surgical stress. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr A30.