Human Prostate Cancer Cells Secrete Neuro-Protective Factors in Response to Cryotherapy

Cryoablation is one of the established treatment modalities for prostate cancer management. Although, it is target specific, it may still lead to damage to the nerve fibers around the prostate tumor. In this study, by directly exposing the co-cultures of prostate cancer cells, PC-3 and Schwann cell-Dorsal Root Ganglion neuron (SC-DRG) to cryo-shock and by exposing SC-DRG to cryo-shock conditioned media (CSCM) obtained from PC-3 cells, robust neuro-protective effects were observed. Since this neuro-protective effect originated from cryotherapy-treated PC-3 cells, the presence of putative factors secreted by PC-3 cells in the medium following cryo-shock was analyzed. Using human cytokine antibody array analysis, differential release of cytokines in CSCM was observed with induced release of cytokines involved in neuro-protection like IL-1α, MIP-4, MIP-5, Leptin, IL-15 and ICAM-1 with simultaneous inhibition of TNFRI and TNFRII that are implicated in killing of nerve cells. Further, using Matrix Assisted Laser Desorption/Ionization-Time Of Flight (MALDI-TOF) sequencing, two proteins were identified namely, CypA (cyclophilin A) and NM23 (nonmetastatic protein 23) in the CSCM. CypA functions as a mediator of intracellular as well as extracellular neuro-protective mechanisms and NM23 has been implicated as a potential suppressor protein of tumor metastasis. Thus, this study revealed the presence of factors in CSCM that has the potential to protect normal neuronal cells and suppress metastasis.