Expression of CD133 confers malignant potential by regulating metalloproteinases in human hepatocellular carcinoma.
OBJECTIVE
Although CD133 expression is identified as a cancer stem cell marker of hepatocellular carcinoma (HCC), the detailed characteristics of HCC cells expressing CD133 remain unclear.


METHODS
We examined the malignant characteristics of CD133-expressing HCC cells.


RESULTS
CD133-expressing cells could be detected with low frequency in 5 HCC tissues. We derived two different HCC cell lines by (1) transfection of CD133 siRNA in PLC/PRF/5 cells in (CD133si-PLC/PRF/5), and (2) by a magnetic cell sorting method that allowed to divide Huh7 cells into two CD133 positive (+) and negative (-) groups. CD133 knockdown in PLC/PRF/5 cells resulted in a decrease of the mRNA and protein expressions of matrix metalloproteinase (MMP)-2 and a disintegrin and metalloproteinase (ADAM)9. We next examined the malignant characteristics related to decreasing MMP-2 and ADAM9 in HCC cells. In CD133si-PLC/PRF/5 cells and CD133- Huh7 cells, invasiveness and vascular endothelial growth factor (VEGF) production, which are both related to the activity of MMP-2, were inhibited compared CD133-expressing HCC cells. We previously demonstrated that ADAM9 protease plays critical roles in the shedding of MHC class I-related chain A (MICA) which regulates the sensitivity of tumor cells to natural killer cells (NK). Decreasing ADAM9 expression in CD133si-PLC/PRF/5 cells and CD133- Huh7 cells resulted in an increase in membrane-bound MICA and a decrease in soluble MICA production. Both CD133si-PLC/PRF/5 cells and CD133- Huh7 cells were susceptible to NK activity, depending on the expression levels of membrane-bound MICA, but CD133-expressing HCC cells were not.


CONCLUSIONS
These results demonstrate that CD133 expression in HCC cells confers malignant potential which may contribute to the survival of HCC cells.
Kohga
Keisuke
K
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Tatsumi
Tomohide
T
Takehara
Tetsuo
T
Tsunematsu
Hinako
H
Shimizu
Satoshi
S
Yamamoto
Masashi
M
Sasakawa
Akira
A
Miyagi
Takuya
T
Hayashi
Norio
N
D000071916:AC133 Antigen; D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002470:Cell Survival / Q000502:physiology; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D056945:Hep G2 Cells; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D018189:Immunomagnetic Separation; D007694:Killer Cells, Natural / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D010455:Peptides / Q000235:genetics* / Q000378:metabolism*; D034622:RNA Interference; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; D008565:Membrane Proteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D051722:ADAM Proteins; C098339:ADAM9 protein, human; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2