Up-regulation of cytoskeletal-associated protein 2 in primary human gastric adenocarcinomas.
METHODS
We performed differential-display polymerase chain reaction to find up-regulated sequences in primary human gastric cancers, and cloned one up-regulated sequence, which was expressed in all the gastric cancer cells that we examined. The cloned sequence was identified as cytoskeletal-associated protein 2 (CKAP2). We also cloned a shorter splice variant, CKAP2-s. The CKAP2 or CKAP2-s protein in HeLa cells was localized to microtubule organizing centers (MTOC) and microtubules. This co-localization pattern was disrupted by nocodazole, a microtubule-destabilizing agent.


RESULTS
These observations suggested that CKAP2 might be associated with microtubule networks. CKAP2 protein was detected in neither normal GI tract nor normal gastric mucosa. However, both CKAP2 and CKAP2-s mRNAs were up-regulated in 55% (23 out of 42 samples) of primary human gastric cancers by reverse transcriptase-polymerase chain reaction (RT-PCR). Moreover, CKAP2 proteins were detected in immunohistochemical staining in all the gastric cancer samples that we examined. CKAP2 protein-expressing cells were also found in gastric adenomas. The average number of CKAP2 protein-positive cells in adenocarcinomas was 48.8%, which was significantly higher than the number in tubular adenomas, 9.1%.


CONCLUSIONS
When these points were taken together, we concluded that CKAP2 is up-regulated in primary human gastric adenocarcinomas at high frequency and might be useful for diagnosing and discriminating adenocarcinomas from tubular adenomas of the stomach.
Bae
Chang-Dae
CD
Department of Molecular Cell Biology and Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchundong Jangangu, 440-746 Suwon, Korea. jbpark@med.skku.ac.kr
Sung
Yeon-Sun
YS
Jeon
Sang-Min
SM
Suh
Yousin
Y
Yang
Han-Kwan
HK
Kim
Yong Il
YI
Park
Ki-Ho
KH
Choi
Jongsun
J
Ahn
Geunghwan
G
Park
Joobae
J
D000230:Adenocarcinoma / Q000378:metabolism*; D000328:Adult; D000368:Aged; D017398:Alternative Splicing; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008870:Microtubules / Q000378:metabolism; D008875:Middle Aged; D008969:Molecular Sequence Data; D013274:Stomach Neoplasms / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
C114988:CKAP2 protein, human; D003598:Cytoskeletal Proteins