Multifactorial regulation of E-cadherin expression: an integrative study.
E-cadherin (E-cad) is an adhesion molecule associated with tumor invasion and metastasis. Its down-regulation is associated with poor prognosis for many epithelial tumor types. We have profiled E-cad in the NCI-60 cancer cell lines at the DNA, RNA, and protein levels using six different microarray platforms plus bisulfite sequencing. Here we consider the effects on E-cad expression of eight potential regulatory factors: E-cad promoter DNA methylation, the transcript levels of six transcriptional repressors (SNAI1, SNAI2, TCF3, TCF8, TWIST1, and ZFHX1B), and E-cad DNA copy number. Combined bioinformatic and pharmacological analyses indicate the following ranking of influence on E-cad expression: (1) E-cad promoter methylation appears predominant, is strongly correlated with E-cad expression, and shows a 20% to 30% threshold above which E-cad expression is silenced; (2) TCF8 expression levels correlate with (-0.62) and predict (P < 0.00001) E-cad expression; (3) SNAI2 and ZFHX1B expression levels correlate positively with each other (+0.83) and also correlate with (-0.32 and -0.30, respectively) and predict (P = 0.03 and 0.01, respectively) E-cad expression; (4) TWIST1 correlates with (-0.34) but does not predict E-cad expression; and (5) SNAI1 expression, TCF3 expression, and E-cad DNA copy number do not correlate with or predict E-cad expression. Predictions of E-cad regulation based on the above factors were tested and verified by demethylation studies using 5-aza-2'-deoxycytidine treatment; siRNA knock-down of TCF8, SNAI2, or ZFHX1B expression; and combined treatment with 5-aza-2'-deoxycytidine and TCF8 siRNA. Finally, levels of cellular E-cad expression are associated with levels of cell-cell adhesion and response to drug treatment.
Reinhold
William C
WC
Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA. wcr@mail.nih.gov
Reimers
Mark A
MA
Lorenzi
Philip
P
Ho
Jennifer
J
Shankavaram
Uma T
UT
Ziegler
Micah S
MS
Bussey
Kimberly J
KJ
Nishizuka
Satoshi
S
Ikediobi
Ogechi
O
Pommier
Yves G
YG
Weinstein
John N
JN
D001374:Azacitidine / Q000494:pharmacology; D021121:Branched DNA Signal Amplification Assay; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D018628:Gene Dosage / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D008745:Methylation / Q000187:drug effects; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D000071799:Zinc Finger E-box-Binding Homeobox 1
D015820:Cadherins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D015534:Trans-Activators; D014157:Transcription Factors; C486307:ZEB1 protein, human; D000071799:Zinc Finger E-box-Binding Homeobox 1; D001374:Azacitidine