Abstract: Objective To investigate the virological characteristics of human non⁃small cell lung cancer cell line H1299⁃ACE2 infected with Omicron variant XBB.1.16 spike protein (XBB.1.16⁃S) and its effect on mitochondrial damage in H1299⁃ACE2 cells. Methods The XBB.1.16⁃S gene eukaryotic expression vector (pCMV3⁃XBB.1.16⁃S plasmid) was constructed by using the parental pCMV3⁃SARS⁃CoV⁃2⁃S plasmid as a template and transfected into H1299⁃ACE2 cells, the ability of inducing syncytial formation was compared. The H1299⁃ACE2 cells were infected with SARS⁃CoV⁃2⁃S and XBB.1.16⁃S pseudoviruses after packaging with a double plasmid system, respectively. The luciferase intensity of the host cells after infection was determined. The cleavage efficiency of S protein in the cells was detected by Western blot. MitoTracker green probe was used to observe mitochondrial morphology of stained cells. The levels of mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) of the cells were detected by flow cytometry. Results Compared with the parental pCMV3⁃SARS⁃CoV⁃2⁃S plasmid, key amino acid mutation sites such as T19I, V83A, and G142D in the pCMV3⁃XBB.1.16⁃S plasmid were successfully mutated, and the area of the syncytium formed after transfection into H1299⁃ACE2 cells was significantly reduced (P<0.0001). Compared with those of SARS⁃CoV⁃2⁃S, the luciferase intensity, S protein cleavage efficiency and ROS level of H1299⁃ACE2 cells after being infected with XBB.1.16⁃S were decreased (all P<0.05), while mitochondrial length was longer (P<0.0001), the MMP level was increased (P<0.001). Conclusions The infectivity and mitochondrial damage ability of Omicron variant XBB.1.16⁃S on non⁃small cell lung cancer H1299⁃ACE2 cells were weakened to some extent compared with  the parental virus. This finding lays an important foundation for the study of cellular changes and treatment targets in lung cancer complicated by COVID⁃19.

Key words:  Non?small cell lung cancer, Omicron, XBB.1.16, H1299?ACE2 cells, Mitochondrion