Expression of Ang-2/Tie-2 and PI3K/AKT in colorectal cancer.
OBJECTIVE
To study the expression of angiogenin-2 (Ang-2) and its receptor Tie-2 in colorectal cancer and discuss the possible mechanisms behind this process.


METHODS
Using the streptavidin-peroxidase (SP) immunohistochemical method, paraffin sections from 100 colorectal cancer samples and 10 samples from tumor-adjacent normal tissue (>2 cm from the edge of the gross tumor) were tested for protein expression of Ang-2, Tie-2, PI3K, and AKT. Reverse transcription-polymerase chain reaction and Western blots were further used to measure expression of the 4 genes and proteins in 20 freshly-resected colorectal cancer samples and tumor-adjacent normal tissues.


RESULTS
In colorectal cancer tissues, the expression of the Ang-2, Tie-2, PI3K, and AKT genes and their proteins was significantly higher than in tumor-adjacent normal tissues. Protein expression in poorly-differentiated adenocarcinoma was higher than that in well and moderately differentiated adenocarcinoma. According to Duke's classification, the protein expression in Stages C and D was significantly higher than that in Stages A and B. In the group with lymphatic metastasis, the protein expression was higher than that without lymphatic metastasis.


CONCLUSIONS
In colorectal cancer, the expression of the Ang-2, Tie-2, PI3K, and AKT genes and their proteins is markedly higher than those in tumor-adjacent normal tissues. No correlation was observed between protein expression and gender, location, or histologic type. Correlations did exist between protein expression and differentiation level, stage of Duke's classification, and lymphatic metastasis; in colorectal cancer tissues with lower differentiation levels, higher stages of Duke's classification, and lymphatic metastasis, the expression of all 4 proteins was higher. The study of their expression patterns and relationships with aggression and metastasis will provide a valuable experimental foundation for assessing prognosis and targeted therapy of colorectal cancer.
Affiliated Hospital of Beihua University, Jilin City, China E-mail : jhlhcn@163.com.
Ji-Hong
JH
Zhang
Li-Hua
LH
Wang
Xiang-Jun
XJ
Li
Ai-Ping
AP
Wang
Li-Qun
LQ
Reng
Feng-Guo
FG
Xia
Zhi-Ping
ZP
Yang
Jing
J
Jiang
Xiao-Dan
XD
Wang
Chun-Yang
CY
Wen
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D015153:Blotting, Western; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D051058:Oncogene Protein v-akt / Q000235:genetics*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D042787:Receptor, TIE-2 / Q000235:genetics*; D016610:Tissue Embedding; D015854:Up-Regulation / Q000235:genetics
D012333:RNA, Messenger; D019869:Phosphatidylinositol 3-Kinases; D042787:Receptor, TIE-2; D051058:Oncogene Protein v-akt