Study On The Function And The Related Molecular Mechanism Of FNDC5 In Osteosarcoma

Osteosarcoma(OS)is one of the most common malignant bone tumors in muscle-skeleton system.Osteosarcoma often present in adolescent patients.Proximal tibia and distal femur are the predilection sites of osteosarcoma.The main application of treatment of OS is chemotherapy and limb-salvage surgery.The 5-year survival rate in patients is now 70%,but patient survival has not changed over the recent years.FNDC5 is a type I transmembrane protein.The protein structure of FNDC5 is composed of an N-terminal signal sequence,an irisin domain,a short transmembrane region and a cytosolic C-terminal domain.In recent years,FNDC5 has been found to play a role in the development of various tumors.However,the specific function of FNDC5 in osteosarcoma remains unclear.We have found that FNDC5 is over expressed in the osteosarcoma.According to the statistical analysis,the expression of FNDC5 is associated with recover,metastasis,Enneking staging,and survival time in osteosarcoma.The results of the RTCA and clone forming assays show that FNDC5 promotes OS cell line proliferation.The flow cytometry confirmed that the osteosarcoma cell cycle was stagnant at S stage after the downregulation of FNDC5.An RNA-Seq indicated that the PI3K/Akt pathway may be affected by FNDC5.Western blotting verified that FNDC5 promotes OS cell proliferation via PI3K/Akt signaling.Accordingly,FNDC5 is a crucial gene in OS and is a potential new treatment target.