The Bmi-1 oncoprotein is overexpressed in human colorectal cancer and correlates with the reduced p16INK4a/p14ARF proteins.
To clarify the roles of Bmi-1 in colorectal carcinoma, we examined the expression of Bmi-1 in 41 samples out of 46 colorectal carcinomas by reverse transcription-PCR, whereas all 46 were analyzed by immunostaining. In addition, we analyzed the expression patterns of Bmi-1 in association with p16INK4a and p14ARF (in mouse p19ARF) in a series of colorectal carcinomas. The level of Bmi-1 mRNA in the carcinoma tissues was significantly higher than those of the adjacent non-neoplastic colonic mucosal tissues. Immunohistochemistry for Bmi-1 showed moderate or strong expression levels in 65% (30/46) of colorectal carcinomas. Colorectal carcinomas with moderate or strong Bmi-1 expression were more likely to have low levels of the INK4 locus proteins (p16INK4a/p14ARF) (P<0.07). These results suggested that modulation of Bmi-1 protein might be involved in human colorectal carcinogenesis by repressing the INK4a/ARF proteins.
Kim
Joo Heon
JH
Department of Pathology, Eulji University School of Medicine, Daejeon 301-070, South Korea.
Yoon
Sun Young
SY
Kim
Chang-Nam
CN
Joo
Joung Hyuck
JH
Moon
Sang Kyoung
SK
Choe
In Seong
IS
Choe
Yong-Kyung
YK
Kim
Jae Wha
JW
D000328:Adult; D002277:Carcinoma / Q000378:metabolism*; D002454:Cell Differentiation; D003106:Colon / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000473:pathology; D009369:Neoplasms / Q000473:pathology; D009687:Nuclear Proteins / Q000096:biosynthesis*; D063150:Polycomb Repressive Complex 1; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D025803:Tumor Suppressor Protein p14ARF / Q000096:biosynthesis*; D015854:Up-Regulation; D016335:Zinc Fingers
C069077:BMI1 protein, human; C489421:Bmi1 protein, mouse; D019941:Cyclin-Dependent Kinase Inhibitor p16; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D025803:Tumor Suppressor Protein p14ARF; D063150:Polycomb Repressive Complex 1