Investigation of the expression of irisin and some cachectic factors of experimentally gastric cancer developed mice

Irisin is a recently defined myokine which is released into blood by proteolysis of the extracellular domain of fibronectin type III domain-containing protein 5 (FNDC5) and which causes weight loss by increasing fat oxidation in adipose tissue. Researches made on irisin are limited and its mechanism of action has not yet been elucidated. No study showing its relationship with the neoplasms in which weight loss is frequently seen such as gastric and pancreatic cancers has been found. By taking the weight reducing effect of irisin into consideration, to elucidate if irisin is secreted by experimentally developed mice gastric tumor cells and also if it has any effect on cancer cachexy. In this research, 12 of total 60 BALB/c mice were taken as control group and N-nitroso-N-methylurea (MNU) had been administered orally to the remaining 48. After 150 days, the survived mice were killed by decapitation and their blood and stomach, skeletal muscle, brown and white adipose tissues were taken. At the end of the histopathological evaluation of the stomach tissues, it was decided to create 4 groups of which one for the control group, and the remaining three for MNU administered mice as; with no cancer, precancer and cancer. For the tissue samples, gene expression analyzes of FNDC5 and some cachexy related proteins had been made and in the serum samples the levels FNDC5/irisin, some inflammatory and tumor markers together with cachectic factors had been determined. The levels of the inflammatory and tumor markers and the cachectic factors in the serum samples were found to be significantly higher in the cancer group with respect to the control group. No expression of FNDC5 and zinc-α-2 glycoprotein (ZAG), a cachectic factor, was seen in the gastric tissues of the control and MNU administered groups, whereas a significantly increased FNDC5 expression was found in the both white and brown adipose tissues of the cancer group. In conclusion, it can be mentioned that the increased FNDC5 expression in the white and brown adipose tissues of the cancer developed mice could have a cachectic effect. But, it is not possible to explain the mechanism of the relationship between irisin and gastric cancer development with the results of this study.