Activation of PI3Kγ/Akt pathway mediates bone cancer pain in rats.

Bone cancer pain (BCP) is one of the most common and severe complications in patients suffering from primary bone cancer or metastatic bone cancer such as breast, prostate, or lung, which profoundly compromises their quality of life. Emerging lines of evidence indicate that central sensitization is required for the development and maintenance of BCP. However, the underlying mechanisms are largely unknown. In this study, weinvestigated the role of PI3K/Akt in the central sensitization in rats with tumor cell implantation in the tibia, a widely used model of BCP. Our results showed that PI3K and its downstream target pAkt were up-regulated in a time-dependent manner and distributed predominately in the superficial layers of the spinal dorsal horn neurons, astrocytes and a minority of microglia, and were colocalized with non-peptidergic, calcitonin gene-related peptide-peptidergic, and A-type neurons in dorsal root ganglion ipsilateral to tumor cell inoculation in rats. Inhibition of spinal PI3K suppressed BCP-associated behaviors and the up-regulation of pAkt in the spinal cord and dorsal root ganglion. This study suggests that PI3K/Akt signal pathway mediates BCP in rats.