Cyclin A is a reliable proliferation marker in endometrial cancer cell lines

Cyclin A, a cell cycle regulatory protein, promotes cell proliferation and has been observed to be highly expressed in cancer and to promote tumor growth; however, its value as a marker for endometrial carcinoma has not yet been established. Accordingly, the aim of the present study was to clarify whether cyclin A can be used as a cell proliferation marker using the endometrial carcinoma cell lines Ishikawa and HEC-50B, derived from patients with low-grade and high-grade cancer, respectively. The expression of cyclin A was determined by flow cytometry using double staining with FITC and 7-AAD, and immunocytochemical staining. The results were compared to those of Ki-67, the widely used cell proliferation marker that is considered to be a prognostic marker in endometrial cancer. The flow cytometry results revealed that cyclin A expression was significantly higher in HEC-50B than in Ishikawa cells during the logarithmic growth phase. In addition, cyclin A expression was consistently higher than Ki-67 expression in the examined cell lines. Immunocytochemical staining confirmed cyclin A expression in HEC-50B and Ishikawa cells, demonstrating significantly higher expression during the logarithmic growth phase than during the stationary phase. By contrast, Ki-67 was expressed in almost 90% of the cells, irrespective of their growth state. These results indicate that cyclin A expression is significantly increased in cells with higher proliferative ability and is specifically expressed in cells that have passed the G1-S checkpoint. Therefore, cyclin A may be a reliable proliferation biomarker for endometrioid carcinoma.

[Effect of Hepatitis C virus proteins on the production of proinflammatory and profibrotic cytokines in Huh7.5 human hepatoma cells]

Hepatitis C virus (HCV) is a widespread dangerous human pathogen. Up to 80% of HCV-infected individuals develop chronic infection, which is often accompanied by liver inflammation and fibrosis and, at terminal stages, liver cirrhosis and cancer. Treatment of patients with end-stage liver disease is often ineffective, and even patients with suppressed HCV replication have higher risk of death as compared with noninfected subjects. Therefore, investigating the mechanisms that underlie HCV pathogenesis and developing treatments for virus-associated liver dysfunction remain an important goal. The effect of individual HCV proteins on the production of proinflammatory and profibrotic cytokines in hepatocellular carcinoma Huh7.5 cells was analyzed in a systematic manner. Cells were transfected with plasmids encoding HCV proteins. Cytokine production and secretion was accessed by immunocytochemistry and ELISA of the culture medium, and transcription of the cytokine genes was assessed using reverse transcription and PCR. HCV proteins proved to differ in effect on cytokine production. Downregulation of interleukin 6 (IL-6) production was observed in cells expressing the HCV core, NS3, and NS5A proteins. Production of transforming growth factor β1 (TGF-β1) was lower in cells expressing the core proteins, NS3, or E1/E2 glycoproteins. A pronounced increase in production and secretion of tumor necrosis factor α (TNF-α) was observed in response to expression of the HCV E1/E2 glycoproteins. A higher biosynthesis, but a lower level in the cell culture medium, was detected for interleukin 1β (IL-1β) in cells harboring NS4 and IL-6 in cells expressing NS5В. The finding was possibly explained by protein-specific retention and consequent accumulation of the respective cytokines in the cell.

A breast cancer cell microarray (CMA) as a rapid method to characterize candidate biomarkers

Tissue microarrays (TMAs) have become an invaluable tool in cancer research to evaluate expression and subcellular localization of proteins in cells and tissues. As the catalogs of candidate biomarkers and therapeutic targets become more extensive, there is a need to characterize and validate these targets and biomarkers in cell lines as a primary biological system in research laboratories. Thus, cell microarrays (CMAs) are useful as a high-throughput screening tool. Here, we constructed a CMA containing 32 publicly available immortalized breast cell lines with the goal of creating a method to rapidly screen for antigens of interest in breast cancer research in a relatively easy, rapid and cost-effective manner. As proof of concept, we performed immunocytochemical staining of the HER2 receptor, as the status of this protein is relevant to breast cancer and has previously been reported for these cell lines. We observed a complete concordance of our staining with the published status of HER2 in these cell lines. In addition, we examined the expression of CD44, epithelial markers EpCAM and E-cadherin and tyrosine phosphoproteins. The labeling of these proteins correlates with the known biology of the cell lines. Our results demonstrate the utility of our method to screen for potential biomarkers and therapeutic targets in breast cancer and we suggest that CMAs be used as a general approach in breast cancer research.