Resumen de Overexpression of y-tubulin in non-small cell lung cancer
Nicoletta F. Maounis, Eduarda Dráberová, Eleni Mahera, Maria Chorti, Valentina Caracciolo, Tetyana Sulimenko, Dimitra Riga, Nikolaos Trakas, Aphrodit Emmanouilidou, Antonio Giordano, Pavel Dráber, C. D. Katsetos
We and others have previously shown that increased expression and altered compartmentalization of ?-tubulin may contribute to tumorigenesis and tumor progression (J. Cell Physiol. 2009;223:519-529; Cancer Biol. Ther. 2010;9:66-76). Here we have determined by immunohistochemistry the localization and cellular distribution of ?-tubulin in clinical tissue samples from 109 non-small cell lung cancer (NSCLC) cases. The expression and distribution of ?-tubulin protein and transcripts was also determined in the NSCLC tumor cell lines NCI-H460 (HTB-177) and NCI-H69 (HTB-119) by immunocytochemistry, quantitative immunoblotting and reverse transcription quantitative real-time PCR (RT-qPCR). Polyclonal and monoclonal anti-peptide antibodies recognizing epitopes in the C- or N-terminal domains of ?-tubulins and human gene-specific primers for ?-tubulins 1 (TUBG1) and 2 (TUBG2) were used. In non-neoplastic cells of the airway epithelium in situ, ?-tubulin exhibited predominantly apical surface and pericentriolar localizations. In contrast, markedly increased, albeit heterogeneous and variously prominent ?-tubulin immunoreactivity was detected in clinical tumor specimens and in the NCI-H460 and NCI-H69 cell lines, where tumor cells exhibited overlapping multi-punctate and diffuse patterns of localization. Co-expression of ?-tubulin and Ki-67 (MIB-1) was detected in a population of proliferating tumor cells. A statistically significant increase of ?-tubulin expression was found in Stage III compared to lesser stage tumors (p<0.001 v. Stages I/II) regardless of histological subtype or grade. By quantitative immunoblotting NCI-H460 and NCI-H69 cells expressed higher levels of ?-tubulin protein compared to small airway epithelial cells (SAEC). In both tumor cell lines increase in TUBG1 and TUBG2 transcripts was detected by RT-qPCR. Our results reveal for the first time an increased expression of ?-tubulin in lung cancer.
