MB49 murine urothelial carcinoma: molecular and phenotypic comparison to human cell lines as a model of the direct tumor response to bacillus Calmette-Guerin.
OBJECTIVE
The mouse urothelial carcinoma cell line MB49 is widely used as an in vitro and in vivo model of urothelial carcinoma. Little comparative data exist on the molecular and phenotypic responses of this cell line relative to human cell lines. We compared the effect of bacillus Calmette-Guerin on the MB49 cell line relative to responses previously observed in the human urothelial carcinoma lines T24 (ATCC) and 253J.


METHODS
Molecular end points in MB49 cells after bacillus Calmette-Guerin exposure were signaling pathway activation (NF-kappaB, AP1 and C/EBP), gene expression (IL-6 and p21), HMGB1 release/responsiveness and gene expression profiling at 6 hours. Phenotypic response end points were direct cytotoxicity using dye exclusion, viability on MTT assay, apoptotic sensitivity and cell cycle compartmentalization.


RESULTS
NF-kappaB, AP1, C/EBP, IL-6 and p21 reporter constructs were activated in MB49 cells in response to bacillus Calmette-Guerin. Gene expression profiles showed an inflammatory/immune clustering response. Bacillus Calmette-Guerin decreased cell viability and induced G1 cell cycle arrest. Treatment of MB49 cells with bacillus Calmette-Guerin induced caspase independent cell death while simultaneously decreasing sensitivity to pro-apoptotic agents. Cell death was associated with release of the necrotic cell death marker HMGB1. MB49 cells expressed HMGB1 receptors and activated intracellular NF-kappaB signaling pathways in response to bacillus Calmette-Guerin.


CONCLUSIONS
MB49 cells show molecular and phenotypic responses to bacillus Calmette-Guerin that replicate those observed in human urothelial carcinoma lines. MB49 cells appear to be an excellent model in which to study bacillus Calmette-Guerin as an antitumor agent for urothelial carcinoma.
Department of Urology, Medical College of Wisconsin and Max McGee National Research Center for Juvenile Diabetes, Milwaukee, Wisconsin 53226, USA.
Fanghong
F
Chen
Guangjian
G
Zhang
Yanli
Y
Cao
Martin J
MJ
Hessner
William A
WA
See
D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000818:Animals; D001500:BCG Vaccine / Q000627:therapeutic use*; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy* / Q000235:genetics*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000502:physiology; D006801:Humans; D051379:Mice; D010641:Phenotype; D015398:Signal Transduction / Q000187:drug effects; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000235:genetics*
D000276:Adjuvants, Immunologic; D001500:BCG Vaccine