Identification of cancer-associated proteins by proteomics and downregulation of β-tropomyosin expression in colorectal adenoma and cancer.
Elucidating the molecular mechanism underlying the development of adenoma, the major precursor lesion of colorectal cancer (CRC), would provide a basis for early detection, prevention as well as treatment of CRC. Using the highly sensitive 2-D DIGE method coupled with MS, we identified 24 differentially expressed proteins in adenoma tissues compared with matched normal colonic mucosa and CRC tissues. Fifteen proteins were downregulated and three proteins were upregulated in adenoma tissues when compared with individual-matched normal colonic mucosa. Five proteins were downregulated, while one protein was upregulated in adenoma tissues when compared with matched CRC tissues. A protein, β-tropomyosin (TM-β), recently suggested to be a biomarker of esophageal squamous carcinoma, was downregulated in both adenoma and CRC tissues. Additionally, the reduction in the level of TM-β in adenoma and CRC tissues was further validated by Western blotting (p<0.05) and RT-PCR (p<0.001). Our findings suggest that downregulation of TM-β is involved in the early development of CRC and that differentially expressed proteins might serve as potential biomarkers for detection of CRC.
Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, P. R. China; Gastrointestinal Institute, Sun Yat-Sen University, Guangzhou, P. R. China.
Yan-Xin
YX
Luo
Ji
J
Cui
Lei
L
Wang
Dian-Ke
DK
Chen
Jun-Sheng
JS
Peng
Ping
P
Lan
Mei-Jin
MJ
Huang
Yi-Hua
YH
Huang
Shi-Rong
SR
Cai
Kun-Hua
KH
Hu
Ming-Tao
MT
Li
Jian-Ping
JP
Wang