Up-regulated manganese superoxide dismutase expression increases apoptosis resistance in human esophageal squamous cell carcinomas / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Esophageal cancer is one of the most common malignancies in the world. In order to identify the proteins associated with esophageal squamous cell carcinomas (ESCC), we analyzed the protein profiles of ESCC cases with tumor and matched adjacent normal tissues.</p><p><b>METHODS</b>Two-dimensional electrophoresis (2-DE) was carried out to analyze the protein profiles. Dysregulated protein spots were identified by Matrix-Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) and verified by liquid chromatography/electrospray ionization ion trap-mass spectrometry/mass spectrometry (LC-ESI-IT MS). RT-PCR and immunohistochemistry on tissue microarray were performed to confirm the gene dysregulation in esophageal cancerous tissues. RNA interference (RNAi) was used to knock down the gene expression in ESCC cell lines. Apoptosis assay with annexin V-FITC/PI staining was conducted and cells were analyzed by flow cytometry.</p><p><b>RESULTS</b>2-DE showed that two protein spots with approximate molecular weights and different pI were elevated in 12 out of 18 ESCCs as compared to the corresponding normal tissues. Both the two spots were identified as MnSOD by MALDI-TOF and were verified by LC-ESI-IT MS. MnSOD overexpression was detected in 14 tumors out of 24 cases by RT-PCR and 52 tumors out of 116 cases by immunohistochemistry comparing to normal epithelia. siRNA-mediated silencing of MnSOD in KYSE450 and KYSE150 cell lines revealed that MnSOD protected ESCC cells from apoptosis induced by ultraviolet (UV) and doxorubicin (DOX).</p><p><b>CONCLUSIONS</b>These findings suggest that there existed two isoforms of MnSOD protein in normal and tumor esophageal tissues. MnSOD was overexpressed in ESCC and its up-regulation in esophageal cancer cells was associated with apoptosis resistance.</p>

Strategy for the identification of amplified genes in tumors / 中华医学遗传学杂志

Amplification of genomic DNA is often observed in tumors. The identification of genes in amplified regions may be helpful to the discovery of oncogenes associated with a specific tumor. Array-based comparative genomic hybridization and restriction landmark genomic scanning are applicable to the definition of such regions. The copy number alterations of target genes present in these regions and the levels of their mRNA and protein can be characterized by quantitative PCR and tissue microarray staining with immunohistochemistry. Transfection, RNA interference, cDNA microarray or reverse transcription-multiplex ligation-dependent probe amplification will facilitate demonstrating the role of such amplified genes in the pathogenesis of a specific tumor.