ROR2 is epigenetically inactivated in the early stages of colorectal neoplasia and is associated with proliferation and migration

Ma, Sean S. Q., Srivastava, Sameer, Llamosas, Estelle, Hawkins, Nicholas J., Hesson, Luke B., Ward, Robyn L. and Ford, Caroline E. (2016) ROR2 is epigenetically inactivated in the early stages of colorectal neoplasia and is associated with proliferation and migration. BMC Cancer, 16 . doi:10.1186/s12885-016-2576-7

Author Ma, Sean S. Q.
Srivastava, Sameer
Llamosas, Estelle
Hawkins, Nicholas J.
Hesson, Luke B.
Ward, Robyn L.
Ford, Caroline E.
Title ROR2 is epigenetically inactivated in the early stages of colorectal neoplasia and is associated with proliferation and migration
Journal name BMC Cancer   Check publisher's open access policy
ISSN 1471-2407
Publication date 2016-07-20
Year available 2016
Sub-type Article (original research)
DOI 10.1186/s12885-016-2576-7
Open Access Status DOI
Volume 16
Total pages 12
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2017
Language eng
Formatted abstract
Background: Colorectal cancer (CRC) is closely linked to Wnt signalling, with 94 % of cases exhibiting a Wnt related mutation. ROR2 is a receptor tyrosine kinase that is thought to repress β-catenin dependent Wnt signalling. Our study aims to determine if ROR2 is epigenetically silenced in CRC and determine if in vitro silencing of ROR2 potentiates Wnt signalling, and alters the proliferative, migratory or invasive potential of cells.

Methods: ROR2 expression was examined in CRC cell lines and patient adenomas using qRT-PCR, while COBRA and bisulphite sequencing was used to analyse ROR2 promoter methylation. 258 patient primary tumour samples from publicly available databases were also examined for ROR2 expression and methylation. In addition, the functional effects of ROR2 modulation were investigated in HCT116 cells following ROR2 siRNA knockdown and in RKO and SW620 cells following ectopic ROR2 expression.

Results: Reduced ROR2 expression was found to correlate with ROR2 promoter hypermethylation in colorectal cancer cell lines, carcinomas and adenomas. ROR2 expression was downregulated in 76.7 % (23/30) of CRC cell lines with increasing ROR2 promoter hypermethylation correlating with progressively lower expression. Analysis of 239 primary tumour samples from a publicly available cohort also found a significant correlation between reduced ROR2 expression and increased promoter methylation. Methylation analysis of 88 adenomas and 47 normal mucosa samples found greater percentage of adenoma samples to be methylated. Additional analysis also revealed that adenoma samples with reduced ROR2 expression also possessed ROR2 promoter hypermethylation. ROR2 knockdown in the CRC cell line HCT116 significantly decreased expression of the β-catenin independent Wnt targets genes JNK and NFATC1, increased cellular proliferation and migration but decreased invasion. When ROR2 was ectopically expressed in RKO and SW620 cells, there was no significant change to either cellular proliferation or migration.

Conclusion: ROR2 is frequently epigenetically inactivated by promoter hypermethylation in the early stages of colorectal neoplasia and this may contribute to colorectal cancer progression by increasing cellular proliferation and migration.
Keyword Colorectal cancer
Epigenetic silencing
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
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Created: Wed, 27 Jul 2016, 14:07:41 EST by Amelie Casgrain on behalf of School of Medicine