Skp2 is a crucial component of SCFSkp2 E3 ubiquitin ligase and is often overexpressed in various types of cancer, including prostate cancer (PCa). The epithelial-to-mesenchymal transition (EMT) is involved in PCa progression. The acquisition of a mesenchymal phenotype that results in a cancer stem cell (CSC) phenotype in PCa was described. Therefore, we aimed to investigate the expression and localization of Skp2 in clinical samples from patients with PCa, the association of Skp2 with EMT status, and the role of Skp2 in prostate CSC. We found that nuclear expression of Skp2 was increased in patients with PCa compared to those with benign hyperplasia, and correlated with high Gleason score in PCa patients. Increased Skp2 expression was observed in PCa cell lines with mesenchymal and CSC-like phenotype compared to their epithelial counterparts. Conversely, the CSC-like phenotype was diminished in cells in which SKP2 expression was silenced. Furthermore, we observed that Skp2 downregulation led to the decrease in subpopulation of CD44+CD24- cancer stem-like cells. Finally, we showed that high expression levels of both CD24 and CD44 were associated with favorable recurrence-free survival for PCa patients. This study uncovered the Skp2-mediated CSC-like phenotype with oncogenic functions in PCa.

Center of Biomolecular and Cellular Engineering International Clinical Research Center St Anne´s University Hospital Brno Brno Czech Republic

Department of Chemistry and Toxicology Veterinary Research Institute Brno Czech Republic

Department of Clinical and Molecular Pathology Institute of Molecular and Translational Medicine Faculty of Medicine and Dentistry Palacky University Olomouc Czech Republic

Department of Cytokinetics Institute of Biophysics of the Czech Academy of Sciences Brno Czech Republic

Department of Experimental Biology Faculty of Science Masaryk University Brno Czech Republic

Department of Urology University Hospital Olomouc Czech Republic

Human Oncology and Pathogenesis Program Memorial Sloan Kettering Cancer Center New York New York 10065 USA

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Siegel RL, Miller KD, Jemal A. Cancer statistics, 2018. CA Cancer J Clin. 2018;68:7–30. doi: 10.3322/caac.21442. PubMed DOI

Oskarsson, T., Batlle, E. & Massague, J. Metastatic stem cells: sources, niches, and vital pathways. Cell Stem Cell14, 306–321, 10.1016/j.stem.2014.02.002 S1934–5909(14)00053-8 (2014). PubMed PMC

Sethi S, Macoska J, Chen W, Sarkar FH. Molecular signature of epithelial-mesenchymal transition (EMT) in human prostate cancer bone metastasis. Am J Transl Res. 2010;3:90–99. PubMed PMC

Puhr, M. et al. Epithelial-to-mesenchymal transition leads to docetaxel resistance in prostate cancer and is mediated by reduced expression of miR-200c and miR-205. Am J Pathol181, 2188–2201, 10.1016/j.ajpath.2012.08.011 S0002–9440(12)00653-0 (2012). PubMed

Marin-Aguilera M, et al. Epithelial-to-mesenchymal transition mediates docetaxel resistance and high risk of relapse in prostate cancer. Mol Cancer Ther. 2014;13:1270–1284. doi: 10.1158/1535-7163.MCT-13-0775. PubMed DOI

Ruan D, et al. Skp2 deficiency restricts the progression and stem cell features of castration-resistant prostate cancer by destabilizing Twist. Oncogene. 2017;36:4299–4310. doi: 10.1038/onc.2017.64. PubMed DOI PMC

Li P, Yang R, Gao WQ. Contributions of epithelial-mesenchymal transition and cancer stem cells to the development of castration resistance of prostate cancer. Mol Cancer. 2014;13:55. doi: 10.1186/1476-4598-13-55. PubMed DOI PMC

Habib K, Kumar S, Manikar N, Zutshi S, Fatma T. Biochemical effect of carbaryl on oxidative stress, antioxidant enzymes and osmolytes of cyanobacterium Calothrix brevissima. Bull Environ Contam Toxicol. 2011;87:615–620. doi: 10.1007/s00128-011-0410-0. PubMed DOI

Gangavarapu KJ, et al. Aldehyde dehydrogenase and ATP binding cassette transporter G2 (ABCG2) functional assays isolate different populations of prostate stem cells where ABCG2 function selects for cells with increased stem cell activity. Stem Cell Res Ther. 2013;4:132. doi: 10.1186/scrt343. PubMed DOI PMC

Leao R, et al. Cancer Stem Cells in Prostate Cancer: Implications for Targeted Therapy. Urol Int. 2017;99:125–136. doi: 10.1159/000455160. PubMed DOI

Petkova N, et al. Surface CD24 distinguishes between low differentiated and transit-amplifying cells in the basal layer of human prostate. Prostate. 2013;73:1576–1590. doi: 10.1002/pros.22708. PubMed DOI

Hurt EM, Kawasaki BT, Klarmann GJ, Thomas SB, Farrar WL. CD44+ CD24(−) prostate cells are early cancer progenitor/stem cells that provide a model for patients with poor prognosis. Br J Cancer. 2008;98:756–765. doi: 10.1038/sj.bjc.6604242. PubMed DOI PMC

Salvatori, L. et al. Cell-to-cell signaling influences the fate of prostate cancer stem cells and their potential to generate more aggressive tumors. PLoS One7, e31467, 10.1371/journal.pone.0031467 PONE-D-11-10345 (2012). PubMed PMC

Menchon C, Edel MJ, Izpisua Belmonte JC. The cell cycle inhibitor p27Kip(1) controls self-renewal and pluripotency of human embryonic stem cells by regulating the cell cycle, Brachyury and Twist. Cell Cycle. 2011;10:1435–1447. doi: 10.4161/cc.10.9.15421. PubMed DOI PMC

Polyak, K. et al. Cloning of p27Kip1, a cyclin-dependent kinase inhibitor and a potential mediator of extracellular antimitogenic signals. Cell78, 59–66, doi:0092-8674(94)90572-X (1994). PubMed

Toyoshima, H. & Hunter, T. p27, a novel inhibitor of G1 cyclin-Cdk protein kinase activity, is related to p21. Cell78, 67–74, doi:0092-8674(94)90573-8 (1994). PubMed

Yang G, et al. Elevated Skp2 protein expression in human prostate cancer: association with loss of the cyclin-dependent kinase inhibitor p27 and PTEN and with reduced recurrence-free survival. Clin Cancer Res. 2002;8:3419–3426. PubMed

Osoegawa A, et al. Regulation of p27 by S-phase kinase-associated protein 2 is associated with aggressiveness in non-small-cell lung cancer. J Clin Oncol. 2004;22:4165–4173. doi: 10.1200/JCO.2004.01.035. PubMed DOI

Chen L, Tweddle DA. p53, SKP2, and DKK3 as MYCN Target Genes and Their Potential Therapeutic Significance. Front Oncol. 2012;2:173. doi: 10.3389/fonc.2012.00173. PubMed DOI PMC

Bochis OV, Fetica B, Vlad C, Achimas-Cadariu P, Irimie A. The Importance of Ubiquitin E3 Ligases, SCF and APC/C, in Human Cancers. Clujul Med. 2015;88:9–14. PubMed PMC

Pernicova Z, et al. Androgen depletion induces senescence in prostate cancer cells through down-regulation of Skp2. Neoplasia. 2011;13:526–536. doi: 10.1593/neo.11182. PubMed DOI PMC

van Duijn PW, Trapman J. PI3K/Akt signaling regulates p27(kip1) expression via Skp2 in PC3 and DU145 prostate cancer cells, but is not a major factor in p27(kip1) regulation in LNCaP and PC346 cells. Prostate. 2006;66:749–760. doi: 10.1002/pros.20398. PubMed DOI

Shim EH, et al. Expression of the F-box protein SKP2 induces hyperplasia, dysplasia, and low-grade carcinoma in the mouse prostate. Cancer Res. 2003;63:1583–1588. PubMed

Lin HK, et al. Skp2 targeting suppresses tumorigenesis by Arf-p53-independent cellular senescence. Nature. 2010;464:374–379. doi: 10.1038/nature08815. PubMed DOI PMC

Remšík J, et al. Trop-2 plasticity is controlled by epithelial-to-mesenchymal transition. Carcinogenesis. 2018;39:1411–1418. doi: 10.1093/carcin/bgy095. PubMed DOI

Liao CP, et al. Mouse prostate cancer cell lines established from primary and postcastration recurrent tumors. Horm Cancer. 2010;1:44–54. doi: 10.1007/s12672-009-0005-y. PubMed DOI PMC

O’Neill AJ, et al. Characterisation and manipulation of docetaxel resistant prostate cancer cell lines. Mol Cancer. 2011;10:126. doi: 10.1186/1476-4598-10-126. PubMed DOI PMC

Slabakova E, et al. Opposite regulation of MDM2 and MDMX expression in acquisition of mesenchymal phenotype in benign and cancer cells. Oncotarget. 2015;6:36156–36171. doi: 10.18632/oncotarget.5392. PubMed DOI PMC

Tellmann, G. The E-Method: a highly accurate technique for gene-expression analysis. Nature Methods, 1–2, 10.1038/nmeth894 (2006).

Mosmann, T. Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods65, 55–63, doi:0022-1759(83)90303-4 (1983). PubMed

Remsik J, et al. Plasticity and intratumoural heterogeneity of cell surface antigen expression in breast cancer. Br. J. Cancer. 2018;118:813–819. doi: 10.1038/bjc.2017.497. PubMed DOI PMC

Vargova J, et al. Hypericin affects cancer side populations via competitive inhibition of BCRP. Biomed Pharmacother. 2018;99:511–522. doi: 10.1016/j.biopha.2018.01.074. PubMed DOI

Bray MA, et al. Cell Painting, a high-content image-based assay for morphological profiling using multiplexed fluorescent dyes. Nat Protoc. 2016;11:1757–1774. doi: 10.1038/nprot.2016.105. PubMed DOI PMC

Carpenter A, et al. CellProfiler: image analysis software for identifying and quantifying cell phenotypes. Genome Biology. 2006;7:R100. doi: 10.1186/gb-2006-7-10-r100. PubMed DOI PMC

Brunger AT. Crystallography & NMR system: A new software suite for macromolecular structure determination. Acta Crystallogr. D. 1998;54:905–921. doi: 10.1107/S0907444998003254. PubMed DOI

Taylor, B. S. et al. Integrative genomic profiling of human prostate cancer. Cancer Cell18, 11–22, 10.1016/j.ccr.2010.05.026 S1535–6108(10)00238-2 (2010). PubMed PMC

Remšík J. et al. Trop-2 plasticity is controlled by epithelial-to-mesenchymal transition. Manuscript submitted for publication (2018). PubMed

Yang Q, et al. Acquisition of epithelial-mesenchymal transition is associated with Skp2 expression in paclitaxel-resistant breast cancer cells. Br J Cancer. 2014;110:1958–1967. doi: 10.1038/bjc.2014.136. PubMed DOI PMC

Qu, X. et al. A signal transduction pathway from TGF-beta1 to SKP2 via Akt1 and c-Myc and its correlation with progression in human melanoma. J Invest Dermatol134, 159–167, 10.1038/jid.2013.281 S0022–202X(15)36471-X (2014). PubMed

Yan W, Chen Y, Yao Y, Zhang H, Wang T. Increased invasion and tumorigenicity capacity of CD44+/CD24− breast cancer MCF7 cells in vitro and in nude mice. Cancer Cell Int. 2013;13:62. doi: 10.1186/1475-2867-13-62. PubMed DOI PMC

Li W, et al. Unraveling the roles of CD44/CD24 and ALDH1 as cancer stem cell markers in tumorigenesis and metastasis. Sci Rep. 2017;7:13856. doi: 10.1038/s41598-017-14364-2. PubMed DOI PMC

Meng E, et al. CD44+/CD24− ovarian cancer cells demonstrate cancer stem cell properties and correlate to survival. Clin Exp Metastasis. 2012;29:939–948. doi: 10.1007/s10585-012-9482-4. PubMed DOI

Ghuwalewala, S. et al. CD44(high)CD24(low) molecular signature determines the Cancer Stem Cell and EMT phenotype in Oral Squamous Cell Carcinoma. Stem Cell Res16, 405–417, 10.1016/j.scr.2016.02.028 S1873–5061(16)00070-2 (2016). PubMed

Klarmann GJ, et al. Invasive prostate cancer cells are tumor initiating cells that have a stem cell-like genomic signature. Clin Exp Metastasis. 2009;26:433–446. doi: 10.1007/s10585-009-9242-2. PubMed DOI PMC

Cremers, N. et al. CD24 Is Not Required for Tumor Initiation and Growth in Murine Breast and Prostate Cancer Models. PLoS One11, e0151468, 10.1371/journal.pone.0151468 PONE-D-15-18809 (2016). PubMed PMC

Lu W, et al. SKP2 inactivation suppresses prostate tumorigenesis by mediating JARID1B ubiquitination. Oncotarget. 2015;6:771–788. doi: 10.18632/oncotarget.2718. PubMed DOI PMC

Zhao, H. et al. Skp2 deletion unmasks a p27 safeguard that blocks tumorigenesis in the absence of pRb and p53 tumor suppressors. Cancer Cell24, 645–659, 10.1016/j.ccr.2013.09.021 S1535–6108(13)00428-5 (2013). PubMed PMC

Puhr M, et al. PIAS1 is a crucial factor for prostate cancer cell survival and a valid target in docetaxel resistant cells. Oncotarget. 2014;5:12043–12056. doi: 10.18632/oncotarget.2658. PubMed DOI PMC

Mulholland DJ, et al. Pten Loss and RAS/MAPK Activation Cooperate to Promote EMT and Metastasis Initiated from Prostate Cancer Stem/Progenitor Cells. Cancer Res. 2012;72:1878–1889. doi: 10.1158/0008-5472.can-11-3132. PubMed DOI PMC

Skp2 and Slug Are Coexpressed in Aggressive Prostate Cancer and Inhibited by Neddylation Blockade