iTRAQ-based quantitative analysis of cancer-derived secretory proteome reveals TPM2 as a potential diagnostic biomarker of colorectal cancer.
Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. We aimed to find novel molecules as potential biomarkers for the early diagnosis of CRC. A serum-free conditioned medium was successfully collected from three pairs of CRC tissue and adjacent normal tissue. iTRAQ-based quantitative proteomic analysis was applied to compare the differences in secretome between primary CRC mucosa and adjacent normal mucosa. A total of 145 kinds of proteins were identified. Of these proteins, 29 were significantly different between CRC and normal tissue. Tropomyosin 2 β (TPM2) exhibited the most significant differences; as such, this protein was selected for further validation. Quantitative real-time PCR indicated that the mRNA expression of TPM2 significantly decreased in the CRC tissue compared with the paired adjacent normal tissue. Immunohistochemical analysis also confirmed that TPM2 was barely detected at protein levels in the CRC tissue. In summary, this study revealed potential molecules for future biomarker applications and provided an efficient approach for the differential analysis of cancer-associated secretome. TPM2 may be valuable for the early diagnosis of CRC.
State Key Laboratory of Molecular Oncology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
Yiming
Y
Ma
State Key Laboratory of Molecular Oncology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
Ting
T
Xiao
Department of Gastrointestinal Cancer Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
Quan
Q
Xu
Department of Gastrointestinal Cancer Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
Xinxin
X
Shao
State Key Laboratory of Molecular Oncology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. hongyingwang@cicams.ac.cn.
Hongying
H
Wang
D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000737:chemistry; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D013058:Mass Spectrometry; D008875:Middle Aged; D040901:Proteomics / Q000379:methods*; D046509:Tissue Culture Techniques; D014335:Tropomyosin / Q000378:metabolism*
D014408:Biomarkers, Tumor; D017077:Culture Media, Conditioned; C518659:TPM2 protein, human; D014335:Tropomyosin
TPM2; colorectal cancer; iTRAQ; secretome