Identification of gastric cancer-related genes using a cDNA microarray containing novel expressed sequence tags expressed in gastric cancer cells.
OBJECTIVE
Gastric cancer is one of the most frequently diagnosed malignancies in the world, especially in Korea and Japan. To understand the molecular mechanism associated with gastric carcinogenesis, we attempted to identify novel gastric cancer-related genes using a novel 2K cDNA microarray.


METHODS
A 2K cDNA microarray was fabricated from 1,995 novel expressed sequence tags (ESTs) showing no hits or a low homology with ESTs in public databases from our 143,452 ESTs collected from gastric cancer cell lines and tissues. An analysis of the gene expression for human gastric cancer cell lines to a normal cell line was done using this cDNA microarray. Data for the different expressed genes were verified using semiquantitative reverse transcription-PCR, Western blotting, and immunohistochemical staining in the gastric cell lines and tissues.


RESULTS
Forty genes were identified as either up-regulated or down-regulated genes in human gastric cancer cells. Among these, genes such as SKB1, NT5C3, ZNF9, p30, CDC20, and FEN1, were confirmed to be up-regulated genes in nine gastric cell lines and in 25 pairs of tissue samples from patients by semiquantitative reverse transcription-PCR. On the other hand, genes such as MT2A and CXX1 were identified as down-regulated genes. In particular, the SKB1, CDC20, and FEN1 genes were overexpressed in > or =68% of tissues and the MT2A gene was down-expressed in 72% of the tissues. Western blotting and immunohistochemical analyses for CDC20 and SKB1 showed overexpression and localization changes of the corresponding protein in human gastric cancer tissues.


CONCLUSIONS
Novel genes that are related to human gastric cancer were identified using cDNA microarray developed in our laboratory. In particular, CDC20 and MT2A represent a potential biomarker of human gastric cancer. These newly identified genes should provide a valuable resource for understanding the molecular mechanism associated with tumorigenesis of gastric carcinogenesis and for the discovery of potential diagnostic markers of gastric cancer.
Kim
Jeong-Min
JM
Laboratory of Human Genomics, Genome Research Center, Korea Research Institute of Bioscience and Biotechnology, Yusong, Daejeon, Korea.
Sohn
Ho-Yong
HY
Yoon
Sun Young
SY
Oh
Jung-Hwa
JH
Yang
Jin Ok
JO
Kim
Joo Heon
JH
Song
Kyu Sang
KS
Rho
Seung-Moo
SM
Yoo
Hyang-Sook
HS
Yoo
Hyan Sook
HS
Kim
Yong Sung
YS
Kim
Jong-Guk
JG
Kim
Nam-Soon
NS
D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007124:Immunoenzyme Techniques; D020411:Oligonucleotide Array Sequence Analysis; D011496:Protein Methyltransferases / Q000235:genetics / Q000378:metabolism*; D011484:Protein-Arginine N-Methyltransferases; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; C577488:CDC20 protein, human; D011496:Protein Methyltransferases; C400529:PRMT5 protein, human; D011484:Protein-Arginine N-Methyltransferases