Quantitative proteome analysis of colorectal cancer-related differential proteins
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To evaluate a new strategy for profiling proteomic changes in colorectal cancer (CRC).
We used laser capture microdissection (LCM) to obtain cells from 20 CRC and paired normal mucosal tissues. The differential proteins between the microdissected tumor cells and normal mucosa epithelia were analyzed by acetylation stable isotopic labeling coupled with L linear ion trap Fourier transform ion cyclotron resonance mass spectrometry (LTQ-FT MS). Western blotting was used to assess the differential expression of proteins. We used bioinformatics tools for cluster and ingenuity pathway analysis of the differential proteins.
In total, 798 confident proteins were quantified and 137 proteins were differentially expressed by at least twofold, including 67 that were upregulated and 70 that were downregulated in cancer. Two differential proteins, solute carrier family 12 member 2 (SLC12A2) and Ras-related protein Rab-10, were validated by Western blotting, and the results were consistent with acetylation stable isotopic labeling analysis. According to gene ontology analysis, CRC-related differential proteins covered a wide range of subcellular locations and were involved in many biological processes. According to ingenuity pathway analysis of the differential proteins, the most relevant canonical pathway associated with CRC was the 14-3-3-mediated signaling pathway, and seven reliable functional networks including cellular growth and proliferation, amino acid metabolism, inflammatory response, embryonic development, carbohydrate metabolism, cellular assembly and organization, and cell morphology were obtained.
Combination of LCM, acetylation stable isotopic labeling analysis and LTQ-FT MS is effective for profiling proteomic changes in CRC cells.
KeywordsColorectal cancer Quantitative proteomics Laser capture microdissection Acetylation stable isotopic labeling
We thank Xiaohong Qian and Xin Liu from Beijing Proteome Research Center for their technical assistance.
This study was supported by Beijing Postdoctoral Research Foundation. The funder played no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Compliance with ethical standards
Conflict of interest
The authors have stated that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.