Sensitivity to epidermal growth factor receptor inhibitor requires E-cadherin expression in urothelial carcinoma cells.
OBJECTIVE
Epidermal growth factor receptor (EGFR) is an attractive target for the treatment of urothelial carcinoma, but a clinical response can be expected in only a small proportion of patients. The aim of this study was to define molecular markers of response to cetuximab therapy in a panel of urothelial carcinoma cell lines.


METHODS
Eleven cell lines were investigated for antiproliferative response to cetuximab based on [(3)H]thymidine incorporation. A variety of markers, including EGFR expression, phosphorylation, and gene amplification, as well as the expression of other growth factor receptors, their ligands, and markers of epithelial-to-mesenchymal transition were investigated. Cohen's kappa statistic was used to estimate the agreement between response and expression of these markers. E-cadherin was silenced by small interfering RNA in two sensitive cell lines, and the effect on the response to cetuximab was measured.


RESULTS
We were able to identify a panel of relevant markers pertaining especially to alternate growth factor receptor expression and epithelial-to-mesenchymal transition that predicted response to cetuximab. The data suggested that expression of intact HER-4 (kappa, 1.00; P = 0.008), E-cadherin (kappa, 0.81; P = 0.015), and beta-catenin (kappa, 0.81; P = 0.015) and loss of expression of platelet-derived growth factor receptor beta (kappa, 0.57; P = 0.167) were associated with response to cetuximab therapy. Silencing E-cadherin in two sensitive cell lines reduced responsiveness to cetuximab in both (P < 0.001).


CONCLUSIONS
A panel of predictive markers for cetuximab response has been established in vitro and is currently being evaluated in a prospective clinical trial of neoadjuvant EGFR-targeted therapy. Most importantly, E-cadherin seems to play a central role in modulation of EGFR response in urothelial carcinoma.
Black
Peter C
PC
Department of Urology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Brown
Gordon A
GA
Inamoto
Teruo
T
Shrader
Marissa
M
Arora
Ameeta
A
Siefker-Radtke
Arlene O
AO
Adam
Liana
L
Theodorescu
Dan
D
Wu
Xifeng
X
Munsell
Mark F
MF
Bar-Eli
Menashe
M
McConkey
David J
DJ
Dinney
Colin P N
CP
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy / Q000378:metabolism / Q000556:secondary; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D000068818:Cetuximab; D004252:DNA Mutational Analysis; D019008:Drug Resistance, Neoplasm; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D020868:Gene Silencing / Q000502:physiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D051379:Mice; D008819:Mice, Nude; D041681:NIH 3T3 Cells; D009361:Neoplasm Invasiveness; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D015820:Cadherins; D034741:RNA, Small Interfering; D066246:ErbB Receptors; D000068818:Cetuximab