Gli2 expression and human bladder transitional carcinoma cell invasiveness.
OBJECTIVE
Hedgehog signaling regulates Gli transcription factors. Aberrant hedgehog signaling can be oncogenic and drugs that block hedgehog are being tested as anticancer agents. We considered whether hedgehog/Gli signaling may be involved in human bladder transitional cell carcinoma proliferative or invasive behavior.


METHODS
We stratified the human bladder transitional cell carcinoma lines RT4 (ATCC), 253JP, 253BV, UMUC6 and UMUC3 for relative growth rate by cell counting and for in vitro invasiveness by Matrigel invasion assay. Cells were tested for growth inhibition by the hedgehog blocking drug cyclopamine or the inactive mimic tomatidine. Cell RNA was characterized for hedgehog signaling component expression, including ligands, receptors and signaling mediators, by quantitative reverse transcriptase-polymerase chain reaction. Gli2 expression or activity was modified by Gli2 expression lentiviruses or the Gli inhibitor GANT61. We measured effects on proliferation and invasiveness.


RESULTS
Cell growth rates and invasiveness were stratified into an equivalent order (RT4 <243JP <253BV <UMUC6 <UMUC3). All cells were weakly growth inhibited by tomatidine and cyclopamine. Gli2 was the only hedgehog signaling molecule of which expression correlated with stratification. Manipulation of Gli2 expression or activity significantly affected cell invasiveness.


CONCLUSIONS
Weak growth suppression by cyclopamine suggests that hedgehog signaling is not involved in bladder cancer cell proliferation but Gli2 expression strongly correlated with invasive behavior. Increased Gli2 expression increased low Gli2 cell invasiveness while Gli inhibition by GANT61 decreased high Gli2 cell invasiveness. Results suggest that Gli2 expression by noncanonical signaling contributes to bladder cancer cell invasiveness.
Mechlin
Clay W
CW
Division of Urology, Albany Medical College, Albany, New York, USA. mianb@mail.amc.edu
Tanner
Matthew J
MJ
Chen
Mengqian
M
Buttyan
Ralph
R
Levin
Robert M
RM
Mian
Badar M
BM
D015153:Blotting, Western; D002295:Carcinoma, Transitional Cell / Q000235:genetics*; D045744:Cell Line, Tumor; D004149:Dioxoles / Q000494:pharmacology; D020869:Gene Expression Profiling; D053823:Hedgehog Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics*; D016014:Linear Models; D009361:Neoplasm Invasiveness / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D010879:Piperazines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics*; D014053:Tomatine / Q000031:analogs & derivatives / Q000494:pharmacology; D001749:Urinary Bladder Neoplasms / Q000235:genetics*; D014704:Veratrum Alkaloids / Q000494:pharmacology; D000075746:Zinc Finger Protein Gli2
C474318:CUR 61414; D004149:Dioxoles; C551027:GANT 61; C082593:GLI2 protein, human; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; D010879:Piperazines; D011725:Pyridines; D011743:Pyrimidines; D014704:Veratrum Alkaloids; D000075746:Zinc Finger Protein Gli2; C003677:tomatidine; D014053:Tomatine; C000541:cyclopamine