[Differential screening of novel human metastasis-associated genes of colorectal carcinoma].
OBJECTIVE
To clone novel metastasis-associated genes of colorectal carcinoma and provide clues for the molecular mechanisms of metastasis of colorectal carcinoma.


METHODS
By suppression subtractive hybridization (SSH), a pair of colorectal carcinoma cell lines with different metastatic potentials derived from the same parental cell line was used to construct two subtractive cDNA library specific for metastasis-accelerating genes or metastasis-suppressor genes. Partial positive clones in the two libraries were selected randomly and differentially screened, and the differentially expressed gene fragments obtained were sequenced and analyzed with BLAST software. The mRNA expressions of several new genes were confirmed by Northern blot analysis.


RESULTS
Two subtractive cDNA libraries had 235 and 232 white clones respectively and more than 90% of the white clones had the inserts. About 200 positive clones selected randomly were differentially screened, and 29 differentially expressed genes were obtained. Fifteen unknown genes were found by sequence and BLAST analysis and had been collected by the GenBank dbEST database with the entry number of CD485499 to CD485513, among which 6 novel genes were located in the fifth chromosome.


CONCLUSIONS
SSH is a reliable strategy for screening novel genes differentially expressed in metastasis of colorectal carcinoma. The fifth chromosome may harbor many new genes related with metastasis of colorectal carcinoma, and identified new genes can be cloned for their full length for further study of their functions.
Liang
Li
L
Department of Pathology, First Military Medical University, Guangzhou 510515, China. lli@fimmu.com
Ding
Yan-qing
YQ
Li
Xin
X
Yang
Yu-fang
YF
Xiao
Jun
J
Zhang
Jin-hua
JH
Zhao
Pei-ran
PR
D001483:Base Sequence; D015179:Colorectal Neoplasms / Q000235:genetics*; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D009362:Neoplasm Metastasis / Q000235:genetics*; D009693:Nucleic Acid Hybridization / Q000379:methods*