title: Biomarkers for predicting response to tyrosine kinase inhibitors in drug-sensitive and drug-resistant human bladder cancer cells.
abstract: The epidermal growth factor receptor (EGFR) family is reportedly overexpressed in bladder cancer, and tyrosine kinase inhibitors (TKIs) have been suggested as treatment. Gefitinib (Iressa®) is a selective inhibitor of the EGFR and lapatinib is a dual inhibitor of both the EGFR and HER2 (human EGFR type 2 receptor). Both compounds compete with the binding of ATP to the tyrosine kinase domain of the respective receptors to inhibit receptor autophosphorylation causing suppression of signal transduction. Unfortunately, resistance to these inhibitors is a major clinical issue. The purpose of the present study was to use protein array analysis to compare the signaling pathway(s) induced by gefitinib and lapatinib, in UM-UC-5 (drug-sensitive) and UM-UC-14 (drug-resistant) bladder cancer cells and to identify molecular markers that may be useful predictors of their efficacy. The results revealed that phosphorylation of EGFR, HER3, Met and ERK1/2 was markedly overexpressed in the sensitive cell line (UM-UC-5) and was strongly inhibited by the TKIs. Other notable differences included decreased phosphorylation of RSK, GSK3, AMPK, Akt and c-Jun by TKIs in the sensitive cells. In contrast, phosphorylated p53 was highly expressed in the resistant cell line (UM-UC-14) and TKIs had no effect in the resistant cells. Overall results suggest that phosphorylated HER3, ERK1/2 and p53 may be used as biomarkers to determine the sensitivity of bladder cancers to TKIs. In particular, a combination of these markers may be more likely to predict the sensitivity to TKIs.
authors.affiliation: Department of Biochemistry and Molecular Biology, Guangdong Medical College, Dongguan, Guangdong 523808, P.R. China.
authors.forename: Jixia
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Guangdong Medical College, Dongguan, Guangdong 523808, P.R. China.
authors.forename: Bihua
authors.initials: B
authors.lastname: Lin
authors.affiliation: Department of Biochemistry and Molecular Biology, Guangdong Medical College, Dongguan, Guangdong 523808, P.R. China.
authors.forename: Xiangyong
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Guangdong Medical College, Dongguan, Guangdong 523808, P.R. China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Tang
authors.affiliation: Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical College, Dongguan, Guangdong 523808, P.R. China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: He
authors.affiliation: Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical College, Dongguan, Guangdong 523808, P.R. China.
authors.forename: Keyuan
authors.initials: K
authors.lastname: Zhou
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000970:Antineoplastic Agents / Q000737:chemistry*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D000077156:Gefitinib; D016158:Genes, p53; D006801:Humans; D000077341:Lapatinib; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009154:Mutation; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000737:chemistry*; D011799:Quinazolines / Q000737:chemistry; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D000077156:Gefitinib; D000077341:Lapatinib; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human; C535150:MAPK1 protein, human