TaqMan® Protein Assays can be used as an effective method for monitoring protein knockdown in cell lines treated with siRNAs. It is faster and uses significantly less material than western blotting. In addition, since very small samples are needed, siRNA effects on other proteins can be analyzed using the same sample. Moreover, correlation analysis with mRNA levels (performed using TaqMan® Gene Expression Assays) may be easily included.
The results for analysis of testicular germ cell tumours (TGCT) and derived cell lines with known expression of OCT3/4 and SOX2 showed that these pluripotency markers are indeed an informative tool for identification of malignant stem cells (seminoma and embryonal carcinoma cells, and their common precursor, carcinoma in situ cells). The findings corroborated observations made using immunohistochemistry, but analysis with TaqMan® Protein Assays enables quantitation, is significantly faster and easier to perform, and uses much smaller sample inputs.