Expression and localization of apolipoprotein M in human colorectal tissues.
BACKGROUND
It has been well documented that apolipoprotein M (apoM) is principally expressed in the liver and kidney. However we found that there was weak apoM expression in other tissues or organs too, which could not be ignored. In the present study, we therefore examined apoM expression in human colorectal tissues including cancer tissues, cancer adjacent normal tissues, polyp tissues and normal mucosa as well as inflammatory mucosa.


METHODS
Tissue samples were collected from patients who underwent surgical resection or endoscopic examination. ApoM mRNA levels were determined by the real-time RT-PCR and apoM protein mass were examined by the immunohistochemistry.


RESULTS
ApoM protein can be detected in all colorectal tissues. However, apoM protein mass were significantly lower in the cancer tissues than its matched adjacent normal tissues, polyp tissues, normal mucosa and inflammatory mucosa. In parallel, apoM mRNA levels in the colorectal cancer tissues (0.0536 ± 0.0131) were also significantly lower than those in their adjacent normal tissues (0.1907 ± 0.0563) (P = 0.033). Interestingly, apoM mRNA levels in colorectal cancer tissues were statistic significant higher in the patients with lymph node metastasis than the patients without lymph node metastasis (P = 0.008). Patients under Dukes' C and D stages had much higher apoM mRNA levels than patients under Dukes' A and B stages (P = 0.034).


CONCLUSIONS
It is concluded that apoM could also be expressed in human colorectal tissues besides liver and kidney. ApoM mRNA levels in the colorectal cancer tissues were significantly increased in the patients with lymph node metastasis. Whether increased apoM expression in the patients with lymph node metastasis being related to patients' prognosis and the physiopathological importance of apoM expression in colorectal tissues need further investigation.
Luo
Guanghua
G
Comprehensive Laboratory, Third Affiliated Hospital, Suzhou University, Changzhou, China.
Zhang
Xiaoying
X
Mu
Qinfeng
Q
Chen
Lujun
L
Zheng
Lu
L
Wei
Jiang
J
Berggren-Söderlund
Maria
M
Nilsson-Ehle
Peter
P
Xu
Ning
N
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology / Q000556:secondary / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001053:Apolipoproteins / Q000235:genetics / Q000378:metabolism*; D000075243:Apolipoproteins M; D003106:Colon / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D007417:Intestinal Polyps / Q000378:metabolism / Q000473:pathology; D054834:Lipocalins; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000378:metabolism; D012007:Rectum / Q000166:cytology / Q000378:metabolism* / Q000473:pathology
C400523:APOM protein, human; D001053:Apolipoproteins; D000075243:Apolipoproteins M; D054834:Lipocalins; D012333:RNA, Messenger