Abstract 5111: A novel β 2 adrenergic-nerve growth factor feed forward loop promotes pancreatic cancer
Authors: Renz Bernhard W. , Macchini Marina , Hayakawa Yoku , Chen Xiaowei , Jiang Zhengyu , Tanaka Takayuki , Westphalen C. Benedikt , Tailor Yagnesh , Werner Jens , Kleespies Axel , Iuga Alina C. , Worthley Daniel L. , Olive Kenneth P. , Wang Timothy C. 
Published: July 2016

Abstract
Introduction and objectives: There is increasing evidence that chronic activation of sympathetic neurons can lead to increased noradrenaline levels in the tumor microenvironment (TME) in PDAC. However, the mechanisms by which adrenergic neurotransmitters are delivered to the TME are not well understood. In this study we aimed to investigate the effect of locally and systemically delivered catecholamines into the TME in two well established genetically engineered mouse models of PDAC (Pdx1-Cre/KRasG12D (KC) and Pdx1-Cre/KRasG12D/Trp53R172H (KPC)).
Methods: Adrenergic signaling was induced or inhibited in KC or KPC mice and in pancreatic organoids using various pharmacological compounds. Adrenergic receptor expression was assessed by RT-PCR, WB and IHC. Downstream pathways were identified by phosphorylation assays and WB. Adrenergic signaling was modeled in vivo applying restraint stress. To elucidate the crosstalk between nerves and cancer cells, pancreatic spheres and PDAC cells were co-cultured with DRGs and neuronal plasticity was quantified. NGF secretion was measured by RT-PCR and ELISA. Sympathetic denervation of the pancreas and blockage of the 2-receptor was employed as a treatment strategy in KPC mice. Overexpression of NGF was targeted to the mouse pancreas using a novel NGF knockin mouse, which was crossed to KC and KPC mice.
Results: ADRB2 was upregulated during pancreatic cancer development. Furthermore, in vitro stimulation of cells harboring an oncogenic KRas mutation with catecholamines resulted in significantly increased sphere forming efficiency. The non-specific -blocker propranolol and the selective 2-blocker ICI 118,551 inhibited this effect. Selective blockade of 2-adrenergic signaling suppressed pancreatic sphere formation caused by co-cultures with DRGs.
NGF secretion was stimulated through beta2-adrenergic signaling. Furthermore, restraint stress accelerated PDAC development in KC mice. The effects of stress were prevented by treatment with the selective ADRB2 antagonist ICI 118,551. Specific β2-blocker treatment as well as sympathetic denervation in addition to GEM significantly increased the survival of mice with 3-5 mm tumors in comparison to controls treated by GEM alone. Targeted overexpression of NGF in the mouse pancreas using a novel NGF knockin mouse resulted in marked acceleration of PanIN lesions in the KC mouse and shortened overall survival in KPC mice significantly. Finally, retrospective analysis of a PDAC patient cohort revealed a extension of overall survival in PDAC patients on non-selective -blockers.
Conclusions: Taken together, these studies suggest that increased catecholamines can engender a feed forward loop, whereby upregulation of NGF can lead to increased innervation and local NE accumulation, thereby enhancing tumor growth. Therapies targeting these adrenergic and NGF pathways may prove useful in the treatment and prevention of pancreatic cancer.
Citation Format: Bernhard W. Renz, Marina Macchini, Yoku Hayakawa, Xiaowei Chen, Zhengyu Jiang, Takayuki Tanaka, C. Benedikt Westphalen, Yagnesh Tailor, Jens Werner, Axel Kleespies, Alina C. Iuga, Daniel L. Worthley, Kenneth P. Olive, Timothy C. Wang. A novel β 2 adrenergic-nerve growth factor feed forward loop promotes pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5111.