Abstract 1193: Sensory innervation directly promotes gastric cancer and modulates the tumor microenvironment
Authors: Zhi Xiaofei , Wu Feijing , Qian Jin , Ochiai Yosuke , Lian Guodong , Malagola Ermanno , Wang Timothy C. 
Published: April 2023

Abstract
Tumor innervation contributes directly to cancer progression, but there appears to be organ-specific variation in the type of innervation. While our previous studies showed cholinergic signaling promoted gastric cancer and vagal denervation inhibited gastric cancer, it is noteworthy that sensory nerves comprise 80% of the vagal axons. To investigate the role of sensory innervation in gastric carcinogenesis, we performed retrograde neural tracing and identified CGRP+ peptidergic neurons in nodose ganglia and dorsal root ganglia as primary gastric sensory neurons. While VAChT+ parasympathetic nerves are the main nerves innervating the normal stomach, CGRP+ sensory nerves show the greatest degree of expansion in mouse gastric tumors. Indeed, mouse gastric tumors show upregulation of NGF, a growth factor essential for sensory nerve survival, and gastric NGF overexpression in an NGF knock-in mouse also resulted in increased sensory innervation. Inhibition of NGF/Trk signaling by Entrectinib markedly attenuates NGF-dependent sensory nerve expansion. In addition to overall increased axonogenesis of sensory nerves, mouse models of gastric cancer showed upregulation of αCGRP peptide in gastric tumors and Calca mRNA in gastric sensory neurons, indicating increased activation of sensory neurons during gastric carcinogenesis. To study the effect of such activation, sensory neurons were then directly activated by treatment of Trpv1-Cre;hM3Dq mice with clozapine-N-oxide (CNO), which led to marked gastric hyperplasia with increased proliferation. Interestingly, in an acetic acid-induced ulcer model, activation of sensory neurons reduced the ulcer size and strongly promoted gland regeneration. Activation of sensory neurons, in a syngeneic, orthotopic model of gastric cancer in the Trpv1-Cre;hM3Dq mice, led to a significant increase in tumor volume, Ki-67+ cancer cells, CD31+ vessels and M2 macrophage polarization, as well as decreased CD8+ T cells. Analysis of available single-cell transcriptome data from mouse and human stomach showed that Calcrl/Ramp1 (CGRP receptors) are expressed in gastric epithelial cells and most stromal cells, while the expression levels of Tacr1 (receptor for Substance P) and Sstr1-5 (receptors for Somatostatin) were much lower. Importantly, some Calcrl/Ramp1+ cells are proliferative cells with strong Ki-67 expression. Our data show that Calcrl is also overexpressed in mouse gastric tumors, while TCGA data reveals significant upregulation of CALCRL in human gastric cancers and that high expression of CALCRL is correlated with poor overall survival. Finally, we established a co-culture model using DRGs and gastric cancer organoids, and found that sensory nerves can generate synaptic-like terminals on cancer organoids. In conclusion, our data indicate that sensory innervation directly promotes gastric cancer growth and also modulates the tumor microenvironment.
Citation Format: Xiaofei Zhi, Feijing Wu, Jin Qian, Yosuke Ochiai, Guodong Lian, Ermanno Malagola, Timothy C. Wang. Sensory innervation directly promotes gastric cancer and modulates the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1193.