Abstract 3026: Role of AnnexinA2, Sema3D and PlexinD1 in mediating perineural invasion as a mechanism of metastasis in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a devastating malignant disease. Upon diagnosis, eighty percent of patients present with metastatic disease. Perineural invasion, the spreading of cancer to the space surrounding or invading the nerve, is often found in surgically removed pancreatic tumors and is associated with a worse overall prognosis including high risk of recurrence and metastasis. Perineural invasion is thought to represent the initial steps of metastasis; however, the mechanism that mediates the role of neurons in precancerous inflammation and pancreatic cancer initiation is not known. We have previously found that Annexin A2 (AnxA2), is a metastasis-associated protein in PDA and is not required for primary PDA growth but is essential for the metastasis in genetically engineered spontaneous pancreatic tumor producing KPC mice. Knock-down of AnxA2 results in diminished metastasis and prolonged survival in mouse liver metastasis models of PDA. Moreover, the presence of perineural invasion is AnxA2 dependent in this model. By comparing tumor cells of AnxA2 wild type vs. knock-out KPC mice, we identified Semaphorin 3D (Sema3D) and PlexinD1 (PlxnD1) were among the most differentially expressed genes. We found that AnxA2 regulates the secretion of Sema3D. Originally characterized as axon guidance genes, ligand Sema3D along with its receptor PlxnD1 and co-receptor, Neuropilin 1 (NP1), are among the cellular pathways most frequently altered at the genetic level in PDA. Moreover, we found that knock down of Sema3D or PlxnD1 suppresses metastasis formation in mouse models of PDA (Foley et al. Science Signaling 2015). In the present study, our lab has found that PNI was present in 9/10 human PDA samples with abundant Sema3D expression compared to only 3/10 human PDA samples with low Sema3D expression. Using a Dorsal Root Ganglion (DRG) invasion assay, we found paracrine signaling between DRG and pancreatic cancer cells is important for increasing tumor cell invasion toward DRGs. Using small interfering RNA for AnxA2 in tumor cells, we find that decrease in AnxA2 significantly decreases tumor invasion. Furthermore, knock down of Sema3D from tumor cells, using shRNA, shows significant decrease in tumor cell invasion toward DRGs. We have also tested the role of the Sema3D receptor, PlexinD1, on DRGs in regulating the invasion of tumor cells towards nerves. A neutralizing antibody for PlexinD1 treated on DRGs caused significant decrease in tumor cell invasion in comparison to DRGs treated with IgG isotype control. These results demonstrate that AnxA2, Sema3D and PlexinD1 are involved in paracrine signaling between the tumor cells and nerves. Taken together, we conclude AnxA2/Sema3D/PlexinD1 signaling may aid in mediating perineural invasion of tumor cells towards nerves as a mechanism of metastasis in pancreatic ductal adenocarcinoma. Citation Format: Noelle R. Jurcak, Kenji Fujiwara, Agnieszka A. Rucki, Kelly Foley, Adrian Murphy, Stephen Muth, Abigail Brittingham, Elizabeth M. Jaffee, Lei Zheng. Role of AnnexinA2, Sema3D and PlexinD1 in mediating perineural invasion as a mechanism of metastasis in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3026.