RESUMEN
Gene copy number aberrations are involved in oral squamous cell carcinoma (OSCC) development. To delineate candidate genes inside critical chromosomal regions, array-CGH was applied to 40 OSCC specimens using a microarray covering the whole human genome with an average resolution of 1 Mb. Gene copy number gains were predominantly found at 1q23 (9 cases), 3q26 (11), 5p15 (13), 7p11 (7), 8q24 (17), 11q13 (15), 14q32 (8), 19p13 (8), 19q12 (7), 19q13 (8), and 20q13 (9), whereas gene copy number losses were detected at 3p21-3p12 (15), 8p32 (11), 10p12 (8), and 18q21-q23 (10). Subsequent mRNA expression analyses by quantitative real time polymerase chain reaction found high mRNA expression of candidate genes SOX2 in 3q26.33, FSLT3 in 19p13.3, and CCNE1 in 19q12. Tissue microarray (TMA) analyses in a representative OSCC collection found gene copy number gain for SOX2 in 52% (115/223) and for CCNE1 in 31% (72/233) of the tumors. Immunohistochemical analyses on TMA sections of the corresponding proteins detected high expression of SOX2 in 18.1% (49/271) and of CyclinE1 in 23.3% (64/275) of tumors analyzed. These findings indicate that SOX2 and CCNE1 might be activated via gene copy number gain and participate in oral carcinogenesis. The combination of array-CGH with TMA analyses allows rapid pinpointing of novel promising candidate genes, which might be used as therapeutic stratification markers or target molecules for therapeutic interference.
Asunto(s)
Carcinoma de Células Escamosas/genética , Ciclina E/genética , Dosificación de Gen , Neoplasias de Cabeza y Cuello/genética , Proteínas Oncogénicas/genética , Factores de Transcripción SOXB1/genética , Cromosomas Humanos/genética , Genoma Humano/genética , Humanos , ARN Mensajero/análisis , Recurrencia , Factores de Transcripción SOXB1/biosíntesis , Análisis de Matrices TisularesRESUMEN
Head and neck squamous cell carcinoma (HNSCC) is a solid malignant neoplasm exhibiting aggressive phenotypes and high recurrence rates. To improve its clinical management, understanding the molecular basis of HNSCC development is of critical importance. For the investigation of tumor-associated genes, functional analyses in well-characterized tumor cell systems are required. To establish an experimental platform, a set of 20 HNSCC cell lines was screened for genetic imbalances by chromosomal comparative genomic hybridization (cCGH). Frequent DNA copy number gains were detected on 3q26.3-qter, 5p, 7p11-p13, 8q23-qter, 9p11-p13, 9q31-qter, 11q13 and 20q13.1, whereas copy number losses were found on 3p, 4p, 4q32.1-qter, 8p11-p12 and 18q22 in agreement with previous observations on genetic aberrations detected in primary HNSCC specimens. Subsequent mRNA expression analysis of 11q13 candidate genes CCND1 and CTTN revealed that HNSCC cell lines exhibiting a DNA copy number gain on 11q13 had a higher transcript level of CCND1 and CTTN compared with HNSCC cell lines without 11q13 copy number gain (P = 0.014 and P = 0.009, respectively). Furthermore, CCND1 and CTTN amplification as detected by fluorescence in situ hybridization correlated with protein expression as assessed by immunocytochemistry. In summary, the cytogenetic characterization illustrates that this set of HNSCC cell lines is representative for the HNSCC genome and provides tumor model systems for detailed analysis of genes with a possible role in the pathomechanism of head and neck tumors.
Asunto(s)
Carcinoma de Células Escamosas/genética , Línea Celular Tumoral , Cromosomas Humanos Par 11/genética , Cortactina/genética , Ciclina D1/genética , Neoplasias de Cabeza y Cuello/genética , Modelos Genéticos , Carcinoma de Células Escamosas/metabolismo , Hibridación Genómica Comparativa , Cortactina/biosíntesis , Ciclina D1/biosíntesis , Dosificación de Gen , Neoplasias de Cabeza y Cuello/metabolismo , Humanos , Hibridación Fluorescente in Situ , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Reacción en Cadena de la Polimerasa , ARN Mensajero/análisisRESUMEN
Despite its common histology and presentation, oral squamous cell carcinoma (OSCC) is associated with widely varying clinical behaviour and response to therapy. To further elucidate the molecular basis of OSCC, an approach for gene expression analysis termed comparative expressed sequence hybridization (CESH) was used in the present study. This straightforward approach allows the rapid delineation of pathophysiologically interesting candidate chromosome regions by a direct detection of aberrant transcriptional activation. CESH profiling of OSCC specimens led to the identification of several novel chromosomal regions. Increased expression compared to a set of control mucosa specimens was found on 1q22-q23, 3q26.3-qter, 4q31.1-q32, 11q12-q13.2, 14q32, 18q12, 19q13.2-q13.3 and 22q13.1-q13.2. Decreased expression was found on 8p22-p23, 16p12 and 16q23-q24. Using CESH, common patterns of altered sequence expression in different OSCC samples were obtained. While some of these regions overlap with those known to be frequently altered in OSCC on the genomic level, this screen revealed novel chromosome subregions with increased transcriptional activity, which are probably independent of the genomic status of the tumor cells.