Sensory neurons drive pancreatic cancer progression through glutamatergic neuron-cancer pseudo-synapses.

Cancers thrive on neuronal input. Here, we demonstrate the presence of pseudo-synaptic connections between sensory nerve endings and cancer cells in an extracerebral cancer, i.e., pancreatic ductal adenocarcinoma (PDAC). These synaptic sites exhibit a selective enrichment of the glutamatergic N-methyl-D-aspartate receptor (NMDA) receptor subunit NMDAR2D (GRIN2D) on the cancer cells, which turns PDAC cells responsive to neuron-derived glutamate and promotes tumor growth and spread. Intriguingly, neurons transform a subset of co-cultured PDAC cells into calcium-responsive cells via GRIN2D-type glutamate receptors at the neuron-cancer pseudo-synapses. We found that the expression of this subunit is due to the increased glutamate availability provided by sensory innervation in a neurotrophic feedforward loop. Moreover, interference with the glutamate-GRIN2D signaling at these neuron-cancer pseudo-synapses markedly improved survival in vivo. This discovery of peripheral cancer-neuron pseudo-synapses may provide an opportunity for cancer-neuroscience-instructed oncological therapies.