MEOX1 Inhibits Growth and Metastasis of Salivary Adenoid Cystic Carcinoma

Salivary adenoid cystic carcinoma (SACC) is a malignant salivary gland neoplasm characterized by aggressive local invasion and a marked propensity for metastasis. However, the role of MEOX1 in SACC progression remains poorly defined. In this study, we examined the effects of MEOX1 overexpression on the malignant behavior of SACC cells in vitro and in vivo. Human SACC-83 and SACC-LM cells were transduced with lentiviral vectors encoding MEOX1 or an empty vector control, and cell proliferation, migration, invasion, and cell cycle distribution were assessed using CCK-8, wound healing, Transwell, and flow cytometric assays, respectively. RNA sequencing was performed to characterize transcriptional changes associated with MEOX1 overexpression. In vivo, tumor growth was evaluated in BALB/c nude mice bearing subcutaneous xenografts, and pulmonary metastatic colonization was assessed using a tail vein injection model. MEOX1 overexpression reduced the proliferation, migration, and invasion of SACC cells in vitro and increased the G2/M phase fraction. In xenograft models, MEOX1-overexpressing cells formed smaller tumors and showed lower Ki67 staining than control cells. In the experimental lung metastasis model, mice injected with MEOX1-overexpressing cells developed fewer pulmonary metastatic nodules. RNA-seq identified 588 differentially expressed genes associated with MEOX1 overexpression, with enrichment in pathways including cytokine-cytokine receptor interaction, Toll-like receptor signaling, and G protein-coupled receptor signaling. Together, these findings indicate that enforced MEOX1 expression is associated with reduced malignant phenotypes in SACC models and with transcriptomic alterations in pathways related to immune response, G protein-coupled receptor signaling, and DNA damage response.