Comparative proteomic study for profiling differentially expressed proteins between Chinese left- and right-sided...

Area of Science:

• Proteomics and molecular oncology
• Biomarker discovery in cancer research

Background:

• Colon cancer exhibits heterogeneity based on tumor location.
• Left-sided colon cancer (LSCC) and right-sided colon cancer (RSCC) may possess distinct molecular characteristics.
• Understanding these differences is crucial for targeted therapies and improved prognoses.

Purpose of the Study:

• To identify and profile differentially expressed protein markers between LSCC and RSCC.
• To compare protein expression patterns to understand molecular distinctions.
• To correlate protein expression with tumor location and potential biological functions.

Main Methods:

• Proteomic analysis using two-dimensional electrophoresis and MALDI-TOF-MS on fresh tumor tissues (n=7 per group).
• Validation of key protein markers via Western blotting.
• Quantitative analysis of four differentially expressed proteins in paraffin-embedded samples (n=50 per group) using tissue microarray and immunohistochemistry.

Main Results:

• Sixteen proteins showed differential expression between LSCC and RSCC.
• Ten proteins, including Heat Shock Protein 60 (HSP-60) and Protein Disulfide Isomerase A1 (PDIA1), were upregulated in LSCC (P < 0.01 or P < 0.05).
• Six proteins, including Elongation Factor 1 Delta (EEF1D) and Heat Shock Protein 27 (HSP-27), were upregulated in RSCC (P < 0.01 or P < 0.05).

Conclusions:

• Proteomic biomarkers differ significantly between LSCC and RSCC.
• Upregulated proteins are primarily involved in cellular energy metabolism, protein folding/unfolding, and oxidative stress.
• These molecular differences likely contribute to variations in tumorigenesis, progression, and prognosis between left- and right-sided colon cancers.