Biologic effect of neurogenesis in pancreatic cancer.

Pancreatic cancer (PaCA) is a deadly disease with few systemic therapeutic options. The head of the pancreas is the most innervated part and most common location of cancer. However, little is known about the contribution of the nerve-cancer interaction to facilitate pancreatic progression. To quantify PaCA axonogenesis, we used a 3-dimensional in vitro neurogenesis model. In addition, neurogenesis in human PaCA was analyzed using PGP9.5 immunohistochemistry, deconvolution imaging, and image segmentation and analysis. There was a significant increase of the total area of neurites in the in vitro coculture with dorsal root ganglia group than control. The nerve density in PaCA tissue was significantly higher than normal pancreatic tissue. To study the functional role of nerves in PaCA, male athymic nude (Nu-Nu) mice were divided into 3 groups: (A) animals were coinjected with MIA PaCa-2 cells and 20U/kg weight units of Botulinum toxin (Botox) (n=10); (B) first injected with Botox and 6weeks later MIA PaCa-2 cancer cells (n=4); and (C) control animals were injected with equivalent amounts of saline fluid (n=9). Animals were sacrificed 6weeks later. Tumor size and apoptotic count (terminal deoxynucleotidyl transferase dUTP nick-end labeling) were measured. Tumor size was decreased and apoptotic rate increased in Botox-treated PaCA. Our data indicate that neural microenvironment may play an important role in the progression of PaCA. It may lead to novel nerve-targeted coadjuvant therapies for PaCA.