Hypalgesia effect of IL-24, a quite new mechanism for IL-24 application in cancer treatment.

Abstract

Tumor suppressor melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) has been extensively regarded as an anti-oncogene; however, that whether IL-24, as a member of IL-10 family, is involved in cancer pain was seldom reported before. In this study, we found that IL-24 mediated by adenovirus could significantly increase the plantar mechanical pain threshold in both operation side and contralateral side of the animal models, which were established by injecting 5×103 Walker 256 rat breast cancer ascitic tumor cells into rats' tibia bone medullary canals; IL-24 could also suppress in vitro Walker 256 cells growth by inducing cell apoptosis. Pathologically, IL-24 could protect bone trabecula and substantia corticalis ossium from being completely destructed. Enzyme-linked immunosorbent assay (ELISA) showed that IL-24 treatment could increase the β-endorphin levels and decrease the IL-6 concentration in plasma of animals. Our study indicated that IL-24 has a potential treatment effect on cancers not only by inhibiting tumor proliferation, but also by the promotion of β-endorphin synthesis, inhibition of IL-6 secretion to relieve cancer pain.