Simultaneous double labelling of routinely processed paraffin tissue sections using combined immunoperoxidase, immunofluorescence, and digital image editing

The comparison of methods to identify the presence of fibrocytes in formalin-fixed, paraffin-embedded archival cardiac tissue with coronary heart disease

The purpose of this study was to find the optimal technical approach to identify the presence of fibrocytes in formalin-fixed, paraffin-embedded archival cardiac tissue with CHD (coronary heart disease). Using the coexpression markers CD45 and αSMA, the presence of fibrocytes was examined by three different methods, including double immunohistochemistry staining, combination labeling of immunohistochemistry and immunofluorescence and double immunofluorescence labeling. Double immunohistochemistry staining was very difficult to identify the CD45(+)/αSMA(+) fibrocytes. Although combination staining of immunohistochemistry and immunofluorescence has made it possible to evaluate the co-localization of CD45 and αSMA in the fibrocytes, this method was prone to produce many false positive cells. In contrast, CD45(+)/αSMA(+) fibrocytes could be clearly recognized by double immunofluorescence labeling. In conclusion, double immunofluorescence labeling is the optimal technical approach to identify the presence of fibrocytes in routinely processed cardiac tissue with CHD.

Bidirectional regulation of manganese superoxide dismutase (MnSOD) on the radiosensitivity of esophageal cancer cells

The mitochondrial antioxidant protein manganese superoxide dismutase (MnSOD) may represent a new type of tumor suppressor protein. Overexpression of the cDNA of this gene by plasmid or recombinant lentiviral transfection in various types of cancer leads to growth suppression both in vitro and in vivo. We previously determined that changes in MnSOD expression had bidirectional effects on adriamycin (ADR) when combined with nitric oxide (NO). Radiation induces free radicals in a manner similar to ADR, so we speculated that MnSOD combined with NO would also have a bidirectional effect on cellular radiosensitivity. To examine this hypothesis, TE-1 human esophageal squamous carcinoma cells were stably transfected using lipofectamine with a pLenti6-DEST plasmid containing human MnSOD cDNA at moderate to high overexpression levels or with no MnSOD insert. Blastidicin-resistant colonies were isolated, grown, and maintained in culture. We found that moderate overexpression of MnSOD decreased growth rates, plating efficiency, and increased apoptosis. However, high overexpression increased growth rates, plating efficiency, and decreased apoptosis. When combined with NO, moderate overexpression of MnSOD increased the radiosensitivity of esophageal cancer cells, whereas high MnSOD overexpression had the opposite effect. This finding suggests a potential new method to kill certain radioresistant tumors and to provide radioresistance to normal cells.

Effects of manganese superoxide dismutase (MnSOD) expression on regulation of esophageal cancer cell growth and apoptosis in vitro and in nude mice

Manganese superoxide dismutase (MnSOD) catalyzes superoxide radical (O2 (-)) into hydrogen peroxide (H2O2), which is further catalyzed by the combined action of glutathione peroxidase (GPx) and catalase (CAT) into water and oxygen. MnSOD plays a role in cell protection from superoxide damage. This study aimed to investigate the effects of MnSOD on regulation of esophageal squamous cell carcinoma cell growth, apoptosis, and cell cycle distribution in vitro and tumor formation and growth in nude mouse xenografts. The data showed that differential levels of MnSOD expression had different effects on tumor cell proliferation, apoptosis, plating efficiency (PE), and cell cycle distribution in vitro and tumor formation and growth in nude mice. In particular, high levels of MnSOD expression promoted TE-1 cell growth and PE rate in vitro and in nude mice, whereas moderate MnSOD expression suppressed tumor cell growth and PE rate but induced more cell apoptosis. Thus, these data demonstrated the dual effects of MnSOD protein in esophageal squamous cell carcinoma and further study will confirm these current data.