MAT1 facilitates the lung metastasis of osteosarcoma through upregulation of AKT1 expression

We aimed to elucidate the effects and mechanisms of MAT1 in the progression of osteosarcoma, especially for its lung metastasis.

CCK-8 and flow cytometry assays were carried out to detect the proliferation and apoptosis of osteosarcoma cells. Wound healing and transwell assays were used to determine cell migration and invasion abilities. Real time quantitative PCR (RT-PCR) and western blot technologies were applied to detect the expression levels of RNA and protein, respectively.

The results showed that both the mRNA and protein expression levels of MAT1 were elevated in osteosarcoma tissues with lung metastasis and metastatic lung tissues, particularly in the metastatic lung tissues, as compared to the osteosarcoma tissues without lung metastasis. High expression level of MAT1 in osteosarcoma patients showed a negative association with the overall survival. In addition, upregulation of MAT1 induced significant increases in cell growth, migration and invasion and an obvious inhibition in cell apoptosis in osteosarcoma MG63 and 143B cells, as well as elevated AKT1 expression level. Moreover, knockdown of AKT1 obviously impaired MAT1-mediated promotions in cell migration and invasion in vitro, as well as repressed tumor growth and reduced the number of metastatic lung tumors in xenografted nude mice.

This study reveals that high expression of MAT1 closely related to the poor prognosis and malignant clinical process of osteosarcoma patients. MAT1 serves as a promoter in the lung metastasis of osteosarcoma through increasing AKT1 expression. Our study may provide a potent therapeutic target for the lung metastasis of osteosarcoma.