RAB22A and osteosarcoma: To investigate whether the K7 acetylation of Rab22a-NeoF1 regulates its promoting osteosarcoma metastasis, we generated their stable U2OS cell lines and U2OS/MTX300 cell lines (U2OS/MTX300 cell line is a methotrexate-resistant derivative of the U2OS human osteosarcoma cell line).