Xenograft nude mouse model
Six-week-old male BALB/C nude mice (Vital River Laboratory Animal Technology, Beijing, CHN) were maintained under specific pathogen-free conditions with a 12h light/dark cycle. All animal experiments were performed in accordance with the guide lines for the Care and Use of Laboratory Animals of Zhengzhou University. MG63 cells stably transfected with sh-circ_0001722 lentivirus or control lentivirus were subcutaneously injected into the right upper back of the nude mice (5×106 cells per mouse). Four weeks later, the mice were sacrificed and tumor tissues were collected for examination of the parameters of interest.