Promoter hypomethylation of EpCAM-regulated bone morphogenetic protein gene family in recurrent endometrial cancer.
OBJECTIVE
Epigenetic regulation by promoter methylation plays a key role in tumorigenesis. Our goal was to investigate whether altered DNA methylation signatures associated with oncogenic signaling delineate biomarkers predictive of endometrial cancer recurrence.


METHODS
Methyl-CpG-capture sequencing was used for global screening of aberrant DNA methylation in our endometrial cancer cohort, followed by validation in an independent The Cancer Genome Atlas (TCGA) cohort. Bioinformatics as well as functional analyses in vitro, using RNA interference (RNAi) knockdown, were performed to examine regulatory mechanisms of candidate gene expression and contribution to aggressive phenotype, such as epithelial-mesenchymal transition (EMT).


RESULTS
We identified 2,302 hypermethylated loci in endometrial tumors compared with control samples. Bone morphogenetic protein (BMP) family genes, including BMP1, 2, 3, 4, and 7, were among the frequently hypermethylated loci. Interestingly, BMP2, 3, 4, and 7 were less methylated in primary tumors with subsequent recurrence and in patients with shorter disease-free interval compared with nonrecurrent tumors, which was validated and associated with poor survival in the TCGA cohort (BMP4, P = 0.009; BMP7, P = 0.007). Stimulation of endometrial cancer cells with epidermal growth factor (EGF) induced EMT and transcriptional activation of these genes, which was mediated by the epithelial cell adhesion molecule (EpCAM). EGF signaling was implicated in maintaining the promoters of candidate BMP genes in an active chromatin configuration and thus subject to transcriptional activation.


CONCLUSIONS
Hypomethylation signatures of candidate BMP genes associated with EpCAM-mediated expression present putative biomarkers predictive of poor survival in endometrial cancer.
Authors' Affiliations: Department of Molecular Medicine, Institute of Biotechnology; Department of Urology; Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio; Department of Computer Science, University of Texas at San Antonio, San Antonio, Texas; Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Obstetrics and Gynecology, Tri-Service General Hospital; Laboratory of Epigenetics, Cancer Stem Cells; Department and Graduate Institute of Biochemistry, National Defense Medical Center, Taiwan, Republic of China; Department of Obstetrics and Gynecology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri; Department of Obstetrics and Gynecology, Ohio State University, Columbus, Ohio.
Ya-Ting
YT
Hsu
Fei
F
Gu
Yi-Wen
YW
Huang
Joseph
J
Liu
Jianhua
J
Ruan
Rui-Lan
RL
Huang
Chiou-Miin
CM
Wang
Chun-Liang
CL
Chen
Rohit R
RR
Jadhav
Hung-Cheng
HC
Lai
David G
DG
Mutch
Paul J
PJ
Goodfellow
Ian M
IM
Thompson
Nameer B
NB
Kirma
Tim Hui-Ming
TH
Huang
D000951:Antigens, Neoplasm / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins / Q000235:genetics*; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D018572:Disease-Free Survival; D016889:Endometrial Neoplasms / Q000235:genetics*; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D000071858:Epithelial Cell Adhesion Molecule; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D005260:Female; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000235:genetics; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D034741:RNA, Small Interfering; D017422:Sequence Analysis, DNA; D013534:Survival; D015533:Transcriptional Activation / Q000187:drug effects
D000951:Antigens, Neoplasm; D019485:Bone Morphogenetic Proteins; D015815:Cell Adhesion Molecules; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D034741:RNA, Small Interfering; D004815:Epidermal Growth Factor