Tubulin Cofactor A Functions As A Novel Positive Regulator Of CcRCC Progression, Invasion And Metastasis

Objective Tubulin cofactor A (TBCA) plays crucial roles in modulatingtubulin folding and α/β-tubulin heterodimer polymerization. Here, we identifiedthe aberrant expression of TBCA in clear cell renal cell carcinoma (ccRCC)specimens as well as cell lines, and revealed the function of TBCA as a novelpositive regulator in ccRCC progression, invasion, and metastasis.Methods To delineate the distribution of TBCA protein in clinicalspecimens and cell lines, qRT-PCR, immunohistochemistry and Western blottingassays were performed. MTS assay was employed to evaluate the roles of TBCAin the regulation of ccRCC cell proliferation. To confirm the roles of TBCA, thecolony formation assay and soft agar colony formation assay were studied. Theinvasion and migration ability of ccRCC cells were examined by wound healingassay and transwell assay. Cytometry assay was conducted to evaluate thepotential impact of TBCA in cell cycle progression and cell apoptotic.Fluorescence microscopy was used to study the Mt cytoskeletons in ccRCC cellstransfected with TBCA expression vector, or TBCA shRNA. The molecularmechanisms of TBCA was investigated by examing the expressions of cell cycleregulators via Western blotting.Results qRT-PCR, Western blot, and immunohistochemistry assaysconfirmed TBCA was significantly highly expressed in ccRCC specimens and celllines compared to their corresponding normal kidney tissues and HKC.Accordingly, the influence of TBCA on cell proliferation, apoptosis, andinvasion/migration was detected through overexpression and knockdown of endogenous TBCA protein level in ccRCC cells via plasmids. Silencing of TBCAexpression inhibited the proliferation of786-O cells and Caki-1cells andpromoted the apoptosis of786-O cells. Down-regulation of TBCA expression alsoreduced the invasion and migration ability of786-O cells. Interestingly,overexpression of TBCA did not induce bio-characteristics that directly contrastedto those of TBCA knockdown. Importantly, exploration of the mechanism showedthat TBCA could function via modulating cytoskeleton integration andinfluencing cell cycle progress. Furthermore, down-regulation of TBCAexpression in786-O and Caki-1cells affected cytoskeleton integration and cellsize, induced S/G2cell cycle arrest, and led to cyclineA/E and CDK2aberrantexpression.Conclusion By investigating novel roles of TBCA in regulation of ccRCCcell progression, invasion, and metastasis, our study identified that TBCA may bea potential molecular target for ccRCC therapy.