Epithelial mesenchymal transition induced by the CXCL9/CXCR3 axis through AKT activation promotes invasion and metastasis in tongue squamous cell carcinoma.

The present study aimed to assess the induction of epithelial-mesenchymal transition (EMT), invasion, and metastasis by the chemokine CXCL9/receptor CXCR3 axis in tongue squamous cell carcinoma (TSCC), unveiling the underlying mechanisms and providing new insights into the prevention and treatment of oral cancer metastasis. The expression levels of CXCL9 and CXCR3 in TSCC tissue specimens were determined by immunohistochemistry, assessing differences between samples with cervical lymph node metastasis and those without. Moreover, protein expression or activity in the TSCC Cal-27 cell line was controlled by neutralizing antibodies, gene transfection, or knock-out. Then, alterations of cell proliferation, migration, invasion, and the cytoskeleton were analyzed by CCK-8, cell scratch, Transwell, and cyto-skeleton staining assays, respectively. Alterations of EMT markers (E-cadherin and vimentin) in Cal-27 cells were detected by immunofluorescence and western blotting. In addition, western blotting was utilized to detect protein expression levels of Akt2, p-Akt2, eIF4E and p-eIF4E, and to explore the regulatory roles and mechanisms of the CXCL9/CXCR3 axis in invasion and metastasis. Significantly increased expression levels of CXCL9 and CXCR3 were detected in tissue specimens with lymph node metastasis compared with those without (P<0.01). Overexpression of CXCL9/CXCR3 in Cal-27 cells resulted in cytoskeleton alterations, decreased E-cadherin expression, increased vimentin levels, enhanced migration and invasion (P<0.05), and increased phosphorylated Akt2 and eIF4E levels (P<0.05). These results revealed that in TSCC, the CXCL9/CXCR3 axis could activate the Akt signaling pathway, with EMT and cytoskeleton rearrangement, promoting invasion and metastasis.