Acquiring metastatic competence by oral squamous cell carcinoma cells is associated with differential expression of α-tubulin isoforms

We performed comparative global proteomics analyses of patient-matched primary (686tu) and metastatic (686ln) oscc cells. the metastatic oscc 686ln cells showed greater in vitro migratory/invasive potential and distinct cell shape from their parental primary 686tu cells. ettan dige analysis revealed 1316 proteins spots in both cell lines with >85 to be quantitatively similar (<2 folds) between the two cell lines. however,two protein spots among four serial spots were highly dominant in 686ln cells. mass spectrometry sequencing demonstrated all four spots to be α-tubulin isotypes. further analysis showed no significant quantitative difference in the α-tubulin between the two cell lines either at mrna or protein levels. thus,two distinct isoforms of α-tubulin,probably due to posttranslational modification,were associated with metastatic 686ln cells. immunofluorescence demonstrated remarkable differences in the cytosolic α-tubulin distribution patterns between the two cells. in 686tu cells,α-tubulin proteins formed a normal network composed of filaments. in contrast,α-tubulin in 686ln cells exhibited only partial cytoskeletal distribution with the majority of the protein diffusely distributed within the cytosol. since α-tubulin is critical for cell shape and mobility,our finding suggests a role of α-tubulin isoforms in acquisition of metastatic phenotype and represents potential target for therapeutic intervention. © 2012 becky lou et al.