TY - JOUR
T1 - WNT5A exhibits tumor-suppressive activity through antagonizing the Wnt/β-catenin signaling, and is frequently methylated in colorectal cancer
AU - Ying, Jianming
AU - Li, Hongyu
AU - Yu, Jun
AU - Ka, Man Ng
AU - Fan, Fong Poon
AU - Wong, Sze Chuen Cesar
AU - Chan, Anthony T.C.
AU - Sung, Joseph J.Y.
AU - Tao, Qian
PY - 2008/1/1
Y1 - 2008/1/1
N2 - Purpose: Aberrant activationof the Wnt/β-catenin signaling pathway is associated with multiple tumors including colorectal cancer (CRC). WNT5A is a member of the nontransforming Wnt protein family, whose role in tumorigenesis is still ambiguous. We investigated its epigenetic alteration in CRCs. Experimental Design: We examined its expression and methylation in normal colon, CRC cell lines, and tumors. We also evaluated its tumor-suppressive function and its modulation to Wnt signaling in CRC cells. Results: WNT5A is silenced in most CRC cell lines due to promoter methylation, but is expressed in most normal tissues including the colon, and is unmethylated in normal colon epithelial cells. WNT5A expression could be reactivated by pharmacologic or genetic demethylation, indicating that methylation directly mediates its silencing. WNT5A methylation was frequently detected in CRC tumors (14 of 29, 48%), but only occasionally in paired normal colon tissues (2 of 15, 13%; P = 0.025). Ectopic expression of WNT5A, but not its nonfunctional short-isoform with the WNT domain deleted, in silenced CRC cells resulted in substantial inhibition of tumor cell clonogenicity, which is associated with down-regulated intracellular β-catenin protein level and concomitant decrease in β-catenin activity. Conclusions: WNT5A is frequently inactivated in CRC by tumor-specific methylation, and thus, is a potential biomarker. WNT5A could act as a tumor suppressor for CRC by antagonizing the Wnt/β-catenin signaling.
AB - Purpose: Aberrant activationof the Wnt/β-catenin signaling pathway is associated with multiple tumors including colorectal cancer (CRC). WNT5A is a member of the nontransforming Wnt protein family, whose role in tumorigenesis is still ambiguous. We investigated its epigenetic alteration in CRCs. Experimental Design: We examined its expression and methylation in normal colon, CRC cell lines, and tumors. We also evaluated its tumor-suppressive function and its modulation to Wnt signaling in CRC cells. Results: WNT5A is silenced in most CRC cell lines due to promoter methylation, but is expressed in most normal tissues including the colon, and is unmethylated in normal colon epithelial cells. WNT5A expression could be reactivated by pharmacologic or genetic demethylation, indicating that methylation directly mediates its silencing. WNT5A methylation was frequently detected in CRC tumors (14 of 29, 48%), but only occasionally in paired normal colon tissues (2 of 15, 13%; P = 0.025). Ectopic expression of WNT5A, but not its nonfunctional short-isoform with the WNT domain deleted, in silenced CRC cells resulted in substantial inhibition of tumor cell clonogenicity, which is associated with down-regulated intracellular β-catenin protein level and concomitant decrease in β-catenin activity. Conclusions: WNT5A is frequently inactivated in CRC by tumor-specific methylation, and thus, is a potential biomarker. WNT5A could act as a tumor suppressor for CRC by antagonizing the Wnt/β-catenin signaling.
UR - http://www.scopus.com/inward/record.url?scp=40749119357&partnerID=8YFLogxK
U2 - 10.1158/1078-0432.CCR-07-1644
DO - 10.1158/1078-0432.CCR-07-1644
M3 - Journal article
C2 - 18172252
SN - 1078-0432
VL - 14
SP - 55
EP - 61
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 1
ER -
