Involvement of hepatitis B X-interacting protein (HBXIP) in proliferation regulation of cells.
OBJECTIVE
To investigate the effect of Hepatitis B X-interacting protein (HBXIP) on cell proliferation.


METHODS
A rabbit antibody against HBXIP was generated. The RNA interference (RNAi) fragment of the HBXIP gene was constructed in the pSilencer-3.0-H1 vector termed pSilencer-hbxip. Plasmids of the pcDNA3-hbxip encoding HBXIP gene and pSilencer-hbxip were transfected into human breast carcinoma MCF-7 cells, hepatoma H7402 cells, and the normal human hepatic cell line L-O2, respectively. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and 5-bromo-2-deoxyuridine incorporation assay were applied to detect cell proliferation. MCF-7 cells and L-O2 cells in the cell cycle were examined by flow cytometry. The proteins involved in cell proliferation and cell cycle were investigated by Western blot.


RESULTS
Overexpression of HBXIP resulted in the promotion of proliferation of MCF-7, H7402, and L-O2 cells. Flow cytometry showed that the overexpression of HBXIP promoted the cell proliferation of MCF-7 and L-O2 cells, and led to an increased cell proliferative index in MCF-7 cells (from 46.25% to 58.28%) and L-O2 cells (from 29.62% to 35.54%). Western blot showed that expression levels of c-Myc, Bcl-2, and proliferating cell nuclear antigen were upregulated in MCF-7, H7402, or L-O2 cells, whereas that of p27 was downregulated. However, the RNAi of HBXIP brought opposite results.


CONCLUSIONS
One of the functions of HBXIP is its involvement in cell proliferation.
Wang
Feng-Ze
FZ
Departments of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071, China.
Sha
Li
L
Zhang
Wei-Ying
WY
Wu
Lian-Ying
LY
Qiao
Ling
L
Li
Nan
N
Zhang
Xiao-Dong
XD
Ye
Li-Hong
LH
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis* / Q000235:genetics; D000963:Antimetabolites; D001973:Bromodeoxyuridine; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D034622:RNA Interference / Q000502:physiology; D012334:RNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D014162:Transfection
D048868:Adaptor Proteins, Signal Transducing; D000963:Antimetabolites; C110719:LAMTOR5 protein, human; D012334:RNA, Neoplasm; D001973:Bromodeoxyuridine