eIF3a is over-expressed in urinary bladder cancer and influences its phenotype independent of translation initiation
- 408 Downloads
The eukaryotic translation initiation factor (eIF) 3a, the largest subunit of the eIF3 complex, is a key functional entity in ribosome establishment and translation initiation. In the past, aberrant eIF3a expression has been linked to the pathology of various cancer types but, so far, its expression has not been investigated in transitional cell carcinomas. Here, we investigated the impact of eIF3 expression on urinary bladder cancer (UBC) cell characteristics and UBC patient survival.
Methods and results
eIF3a expression was reduced through inducible knockdown in the UBC-derived cell lines RT112, T24, 5637 and HT1197. As a consequence of eIF3a down-regulation, UBC cell proliferation, clonogenic potential and motility were found to be decreased and, concordantly, UBC tumour cell growth rates were found to be impaired in xenotransplanted mice. Polysomal profiling revealed that reduced eIF3a levels increased the abundance of 80S ribosomes, rather than impairing translation initiation. Microarray-based gene expression and ontology analyses revealed broad effects of eIF3a knockdown on the transcriptome. Analysis of eIF3a expression in primary formalin-fixed paraffin embedded UBC samples of 198 patients revealed that eIF3a up-regulation corresponds to tumour grade and that high eIF3a expression corresponds to longer overall survival rates of patients with low grade tumours.
From our results we conclude that eIF3a expression may have a profound effect on the UBC phenotype and, in addition, may serve as a prognostic marker for low grade UBCs.
KeywordsEukaryotic translation initiation eIFs Urinary bladder cancer Tumour marker
We thank Theresa Eder, Veronika Rauch, Gertrude Zisser and Isolde Gunsch for their excellent technical assistance. We thank Mag. Karin Osibow for critical reading of our manuscript.
Conflict of interest
The authors declare that there is no conflicts of interest.
- 6.G. Johnen, K. Gawrych, H. Bontrup, B. Pesch, D. Taeger, S. Banek, M. Kluckert, H. Wellhäußer, F. Eberle, M. Nasterlack, G. Leng, A. Stenzl, T. Brüning, Performance of survivin mRNA as a biomarker for bladder cancer in the prospective study UroScreen. PLoS One 7, e35363 (2012)PubMedCentralPubMedCrossRefGoogle Scholar
- 8.V. Cebrian, M. Fierro, E. Orenes-Piñero, L. Grau, P. Moya, T. Ecke, M. Alvarez, M. Gil, F. Algaba, J. Bellmunt, C. Cordon-Cardo, J. Catto, A. López-Beltrán, M. Sánchez-Carbayo, KISS1 methylation and expression as tumor stratification biomarkers and clinical outcome prognosticators for bladder cancer patients. Am. J. Pathol. 179, 540–546 (2011)PubMedCentralPubMedCrossRefGoogle Scholar
- 11.T.V. Pestova, J.R. Lorsch, C.U.T. Hellen, The Mechanism of Translation Initiation in Eukaryotes, in Translational Control in Biology and Medicine, ed. by M.B. Mathews, N. Sonenberg, J.W.B. Hershey (Cold Spring Harbor Laboratory Press, New York, 2007), pp. 87–128Google Scholar
- 12.A. Unbehaun, S.I. Borukhov, C.U.T. Hellen, T.V. Pestova, Release of initiation factors from 48S complexes during ribosomal subunit joining and the link between establishment of codon-anticodon base-pairing and hydrolysis of eIF2-bound GTP. Genes Dev. 18, 3078–3093 (2004)PubMedCentralPubMedCrossRefGoogle Scholar
- 13.T. Kouba, I. Danyi, S. Gunisova, V. Munzarova, V. Vlckova, L. Cuchalova, A. Neueder, P. Milkereit, L.S. Valasek, Small ribosomal protein RPS0 stimulates translation initiation by mediating 40S-binding of eIF3 via its direct contact with the eIF3a/TIF32 subunit. PLoS One 7, e40464 (2012)PubMedCentralPubMedCrossRefGoogle Scholar
- 14.R.Y. Liu, Z. Dong, J. Liu, J.Y. Yin, L. Zhou, X. Wu, Y. Yang, W. Mo, W. Huang, S.K. Khoo, J. Chen, D. Petillo, B.T. Teh, C.N. Qian, J.T. Zhang, Role of eIF3a in regulating cisplatin sensitivity and nucleotide excision repair of nasopharyngeal carcinomas. Oncogene 30, 4814–4823 (2012)CrossRefGoogle Scholar
- 16.R. Spilka, K. Laimer, F. Bachmann, G. Spizzo, A. Vogetseder, M. Wieser, H. Müller, J. Haybaeck, P. Obrist, Overexpression of eIF3a in squamous cell carcinoma of the oral cavity and its putative relation to chemotherapy response. J. Oncol. 901956 (2012)Google Scholar
- 18.Z. Wu, R.A. Irizarry, R. Gentleman, F. Martinez Murillo, F. Spencer, A model based background adjustment for oligonucleotide expression arrays. Johns Hopkins University, Dept. of Biostatistics Working Papers. Working Paper 1 (2004)Google Scholar
- 19.G.K. Smyth, Linear models and empirical Bayes methods for assessing differential expression in microarray experiments. Stat. Appl. Genet. Mol. Biol. 3, e29 (2004)Google Scholar
- 20.Y. Benjamini, Y. Hochberg, Controlling the false discovery rate: a practical and powerful approach to multiple testing. J. R Stat. Soc. Ser. B 57, 289–300 (1995)Google Scholar
- 30.S. Khoshnevis, S. Gunisová, V. Vlcková, T. Kouba, P. Neumann, P. Beznosková, R. Ficner, L.S. Valásek, Structural integrity of the PCI domain of eIF3a/TIF32 is required for mRNA recruitment to the 43S pre-initiation complexes. Nucleic Acids Res. 42, 4123–4139 (2014)PubMedCentralPubMedCrossRefGoogle Scholar
- 32.F. Bachman, R. Baenziger, M.M. Burger, Cloning of a novel protein overexpressed in human mammary carcinoma. Cancer Res. 57, 988–994 (1997)Google Scholar
- 37.J. Haybaeck, T. O’Connor, R. Spilka, G. Spizzo, C. Ensinger, G. Mikuz, T. Brunhuber, A. Vogetseder, I. Theurl, W. Salvenmoser, H. Draxl, R. Baenziger, F. Bachmann, G. Schaefer, M.M. Burger, P. Obrist, Overexpression of p150, a part of the large subunit of the eukaryotic translation initiation factor 3, in colon cancer. Anticancer Res. 30, 1047–1056 (2010)PubMedGoogle Scholar
- 38.K.C. Halling, W. King, I.A. Sokolova, R.J. Karnes, R.G. Meyer, E.L. Powell, T.J. Sebo, J.C. Cheville, A.C. Clayton, K.L. Krajnik, T.A. Ebert, R.E. Nelson, H.M. Burkhardt, S. Ramakumar, C.S. Stewart, V.S. Pankratz, M.M. Lieber, M.L. Blute, H. Zincke, S.A. Seelig, R.B. Jenkins, D.J. O’Kane, A comparison of BTA stat, hemoglobin dipstick, telomerase and Vysis UroVysion assays for the detection of urothelial carcinoma in urine. J. Urol. 167, 2001–2006 (2002)PubMedCrossRefGoogle Scholar
- 41.Y.C. Lu, C.N. Chen, B. Wang, W.M. Hsu, S.T. Chen, K.J. Chang, C.C. Chang, H. Lee, Changes in tumor growth and metastatic capacities of J82 human bladder cancer cells suppressed by down-regulation of calreticulin expression. Am. J. Pathol. 179, 1425–1433 (2011)PubMedCentralPubMedCrossRefGoogle Scholar