Identification of MSRA gene on chromosome 8p as a candidate metastasis suppressor for human hepatitis B virus-positive hepatocellular carcinoma.
BACKGROUND
The prognosis of patients with hepatocellular carcinoma (HCC) still remains very dismal, which is mainly due to metastasis. In our previous studies, we found that chromosome 8p deletions might contribute to metastasis of HCC. In this study, we aimed to identify the candidate metastatic suppressor gene on chromosome 8p.


METHODS
Oligo-nucleotide microarrays which included 322 genes on human chromosome 8p were constructed to analyze the difference in gene expression profiles between HCC tissues with and without metastasis. The leading differentially expressed genes were identified and selected for further analysis by real-time PCR and Western blotting. Recombinant expression plasmid vectors for each target gene were constructed and transfected into HCC cells and its in vitro effects on proliferation and invasion of HCC cells were also investigated.


RESULTS
Sixteen leading differentially expressed genes were identified from the HCC tissues with metastasis compared with those without metastasis (p < 0.01, q < 16 %). Among of the 10 significantly down-regulated genes in HCC with metastasis, methionine sulfoxide reductase A (MSRA) had the lowest p value and false discovery rate (FDR), and was considered as a potential candidate for metastasis suppressor gene. Real-time PCR and Western blotting confirmed that the mRNA and protein expression levels of MSRA were significantly decreased in HCC with metastasis compared with those without metastasis (p < 0.001), and MSRA mRNA level in HCCLM6 cells (with high metastatic potential) was also much lower than that of other HCC cell lines. Transfection of a recombinant expression plasmid vector and overexpression of MSRA gene could obviously inhibit cell colony formation (4.33 +/- 2.92 vs. 9.17 +/- 3.38, p = 0.008) and invasion (7.40 +/- 1.67 vs. 17.20 +/- 2.59, p= 0.0001) of HCCLM6 cell line.


CONCLUSIONS
MSRA gene on chromosome 8p might possess metastasis suppressor activity in HCC.
Lei
Ke-Feng
KF
Liver Cancer Institute and Zhongshan Hospital, Institutes of Biomedical Science, Fudan University, Shanghai, China. s78293@163.com
Wang
Yan-Fang
YF
Zhu
Xiao-Qun
XQ
Lu
Peng-Cheng
PC
Sun
Bing-Sheng
BS
Jia
Hu-Liang
HL
Ren
Ning
N
Ye
Qing-Hai
QH
Sun
Hui-Chuan
HC
Wang
Lu
L
Tang
Zhao-You
ZY
Qin
Lun-Xiu
LX
D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology / Q000556:secondary / Q000821:virology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002898:Chromosomes, Human, Pair 8; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006515:Hepatitis B virus / Q000302:isolation & purification*; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology / Q000821:virology; D008297:Male; D051150:Methionine Sulfoxide Reductases; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis / Q000517:prevention & control*; D010088:Oxidoreductases / Q000235:genetics* / Q000502:physiology