Differential protein profiling in renal-cell carcinoma

Characterizing the alterations of protein expression in cancer cells can be very useful in providing insight into the changes in the functional pathways and thus the fundamental mechanisms of cancer development at the molecular level. In this study, we profiled protein expressions in eleven pairs of primary cell cultures derived from renal-cell carcinoma (RCC) tissues and patient-matched normal kidney tissues utilizing two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Together with the immunoblot analysis of proteins from the RCC tissues, the study also demonstrated that the alterations of protein expression observed in RCC primary cell cultures reflected those observed in the original RCC tissues. We analyzed the expression profiles and identified proteins differentially expressed in RCC primary cell cultures by 2-D PAGE and mass spectrometry (MS). We found sixteen proteins were overexpressed and seven proteins underexpressed in RCC. The deregulated expressions of proteins include those involved in metabolism, cellular morphology, heat shock response, cell growth, etc. Overexpression of three proteins, alphabeta-crystallin, manganese superoxide dismutase (MnSOD), and annexin IV, most commonly observed in primary RCC cell cultures, were also observed by immunoblot analysis of proteins from the RCC tissues from which the primary cell cultures were derived. Semi-quantitative reverse transcription (RT)-polymerase chain reaction (PCR) analysis revealed the direct correlation between deregulated gene expression and the corresponding protein abundance in two of the three most commonly upregulated proteins we found in RCC.