Anita Csizmarik1, Thilo Bracht2, Barbara Sitek2, Martin Puhr3, Ilona Tornyi4, József Lázár4, László Takács4, Dávid Keresztes1, Nikolett Nagy1, Boris Hadaschik5, Péter Nyirády1, Tibor Szarvas1,5
1 Department of Urology, Semmelweis University, Budapest, Hungary
2 Medizinisches Proteom-Center, Ruhr University Bochum, Germany
3 Department of Urology, Medical University of Innsbruck, Austria
4 Department of Human Genetics, University of Debrecen, Hungary
5 Department of Urology, University Hospital Essen, University of Duisburg-Essen, Germany
Introduction: Enzalutamide (ENZA) is a new generation antiandrogen therapy which has been demonstrated to increase survival of metastatic castration resistant prostate cancer patients. Unfortunately, baseline and acquired resistance to ENZA have been observed, however their molecular mechanisms are poorly understood.
Aims: Our aim was to identify protein biomarkers involved in ENZA resistance of prostate cancer (PC).
Methods: A comparative proteome analysis were performed on LNCaPabl, DUCaP and LAPC4 PC cell lines and their therapy-resistant pairs by using the LC-MS/MS technique. We applied three different bioinformatic approaches to select the most promising candidate proteins. First, we scored proteins based on their fold change, molecular interactions according to the String database, their published prognostic and predictive values in other cancers, the availability of specific inhibitors and ELISA assays for later serum analyses. Second, potentially secreted proteins were selected by using various online prediction tools (SignalP, SecretomeP, TargetP, TMHMM) and databases (Uniprot, Human Protein Atlas, NCBI, ExoCarta). Third, we performed a cross-reference analysis with one published transcriptome dataset.
Results: We found 278 significantly upregulated proteins in ENZA-resistant cell lines. Applying our scoring criteria, we selected 6 proteins; while the secreted protein prediction method found 7 serum markers and the cross-reference analysis identified further 9 molecules. Based on these, we selected 10 proteins (RhoA, SQSTM1, RRM1, RRM2, NR3C1, NDRG1, AGR2, ALCAM, SCIN, IDH1) for further functional and patients’ serum analyses.
Conclusions: Our comparative proteome analysis identified 278 significantly upregulated proteins in resistant cells and our filtering methods selected the 10 most promising ones for further analyses. These proteins were involved in various cellular processes such as cell cycle, gene expression and metabolism. Next, these proteins will be functionally analysed in order to determine their role in ENZA-resistance and will be measured in serum samples of ENZA-treated patients to evaluate their predictive value.
Doctoral School: Clinical Medicine
Supervisor: Szarvas Tibor
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