DOC-2, a candidate tumor suppressor gene in human epithelial ovarian cancer.
Using RNA fingerprinting (RAP) strategy and Northern blot analysis, we identified a differentially expressed sequence DOC-2 which is detectable in all normal human ovarian surface epithelial (HOSE) cell cultures but not in ovarian cancer cell lines and tissues. Subsequent cloning of DOC-2 from a cDNA library generated from the HOSE cells was carried out using the 3' and 5' RACE approach. A 3268 base pair full length cDNA of DOC-2 was isolated and sequenced. The predicted protein has a length of 770 amino acids. Homology search of all NCBI sequences indicated that the amino acid sequence of DOC-2 shares 93% homology with the mouse p96/mDab2 phosphoprotein and has a phosphotyrosine interacting domain (PID) and multiple SH3 binding motifs. Chromosomal localization by FISH showed that the DOC-2 gene is located on 5p13. Western blot analysis showed that the 105 kDa DOC-2 protein was down-regulated in all the carcinoma cell lines. In-situ immunohistochemistry performed on normal ovaries, and benign, borderline and invasive ovarian tumor tissues showed down regulation of DOC-2 protein particularly in serous ovarian tumor tissues. When DOC-2 was transfected into the ovarian carcinoma cell line SKOV3, the stable transfectants showed significantly reduced growth rate and ability to form tumors in nude mice. These data suggest that down-regulation of DOC-2 may play an important role in ovarian carcinogenesis.
Mok
S C
SC
Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Chan
W Y
WY
Wong
K K
KK
Cheung
K K
KK
Lau
C C
CC
Ng
S W
SW
Baldini
A
A
Colitti
C V
CV
Rock
C O
CO
Berkowitz
R S
RS
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins; D002895:Chromosomes, Human, Pair 5; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D008969:Molecular Sequence Data; D009375:Neoplasms, Glandular and Epithelial / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D012334:RNA, Neoplasm / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; C102885:DAB2 protein, human; D011506:Proteins; D012334:RNA, Neoplasm; D025521:Tumor Suppressor Proteins