Interleukin-12 treatment reduces tumor growth and modulates the expression of CASKA and MIR-203 in athymic mice bearing tumors induced by the HGC-27 gastric cancer cell line

Gastric cancer (GC) is one of the most common malignant tumors in the digestive system and due to its poor prognosis, there is an increase in the demand for more effective anticancer therapies. Interleukins are potential anticancer agents which can modulate expression of cancer related genes and have therapeutic effects. Interleukin 12 (IL-12) exhibits potent anti-tumor, anti-angiogenic and anti-metastatic activities and represents the ideal candidate for tumor immunotherapy, due to its ability to activate both innate and adaptive immunities. The aim of this study was to evaluate the effect of IL-12 administration on GC tumor growth induced in the cancer xenograft nude mouse model. Tumor development was analyzed weekly and after 8 weeks, the animals were sacrificed for cytokine analysis (IL-4, TNF-alfa, IL-2, INF-gamma, IL-12, IL-10, TGF-beta) by ELISA. The tumor cells in the implanted areas of the animals that developed solid growth of the tumor (anatomopathological analysis was performed). We have also evaluated CASK and miR203 expression, two related cell invasion factors, in the induced tumors after administration of 6 n/kg IL-12. The development of tumor masses was observed in all groups of animals inoculated with HGC-27 neoplastic cells. In animals treated with 6 n/kg IL-12, there was no tumor development confirmed by anatomopathological analysis. Changes in the levels of pro and anti-inflammatory cytokines were also observed. Our results indicated that miR203 expression was elevated while CASK was downregulated. These results suggest that IL-12 treatment repress the tumor growth by induction of miR203 expression which in turn repress CASK expression.