Knockdown of Bmi1 inhibits the stemness properties and tumorigenicity of human bladder cancer stem cell-like side population cells

Zhu,Dingjun; Wan,Xuesi; Huang,Hai; Chen,Xu; Liang,Wu; Zhao,Fengjin; Lin,Tianxin; Han,Jinli; Xie,Wenlian

doi:10.3892/or.2013.2919

Knockdown of Bmi1 inhibits the stemness properties and tumorigenicity of human bladder cancer stem cell-like side population cells

Authors:
- Dingjun Zhu
- Xuesi Wan
- Hai Huang
- Xu Chen
- Wu Liang
- Fengjin Zhao
- Tianxin Lin
- Jinli Han
- Wenlian Xie
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Affiliations: Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, P.R. China, Department of Endocrinology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, P.R. China
Published online on: December 13, 2013 https://doi.org/10.3892/or.2013.2919
Pages: 727-736

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Abstract

B-cell-specific Moloney murine leukemia virus insertion site 1 (Bmi1) is directly involved in cell growth, proliferation and self-renewal of cancer stem cells (CSCs). The aim of the present study was to assess the role of Bmi1 in the maintenance of stemness properties and tumorigenicity of human bladder CSC-like side population (SP) cells. SP cells were sorted by flow cytometry using Hoechst 33342 staining. Bmi1 mRNA and protein expression in SP and non-SP (NSP) cells was analyzed by quantitative PCR, immunofluorescence and western blotting. The stemness properties of SP cells included cell proliferation, migration, self-renewal, chemotherapy resistance and cell cycle progression were assessed. Tumor formation was also assessed in human bladder cancer xenografts after Bmi1 silencing. The mRNA expression of Bmi1 was upregulated in SP cells when compared with that in the NSP cells. Knockdown of Bmi1 in SP cells resulted in inhibition of cell proliferation, migration and tumor sphere formation, enhanced sensitivity to cisplatin, and cell cycle arrest in the G0/G1 phase. Bmi1 knockdown inhibited cell cycle progression through derepression of the p16INK4a/p14ARF locus. Bmi1-siRNA SP cells failed to produce tumors in recipient mice, while typical urothelial carcinoma formed from subcutaneously injected scramble-siRNA SP cells. Bmi1 is crucial for the maintenance of stemness properties and tumorigenicity of human bladder CSC-like cells. Bmi1 may be a potential therapeutic target for the eradication of CSCs in bladder cancer.

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1	Han S, Zhang S and Chen W: Analysis of the status and trends of bladder cancer incidence in China. Oncol Progress. 11:89–95. 2013.
2	Ploeg M, Aben KK and Kiemeney LA: The present and future burden of urinary bladder cancer in the world. World J Urol. 27:289–293. 2009. View Article : Google Scholar : PubMed/NCBI
3	Babjuk M, Burger M, Zigeuner R, et al: EAU guidelines on non-muscle-invasive urothelial carcinoma of the bladder: update 2013. Eur Urol. 64:639–653. 2013. View Article : Google Scholar : PubMed/NCBI
4	Enderling H, Hlatky L and Hahnfeldt P: Cancer stem cells: a minor cancer subpopulation that redefines global cancer features. Front Oncol. 3:762013. View Article : Google Scholar : PubMed/NCBI
5	Reya T, Morrison SJ, Clarke MF and Weissman IL: Stem cells, cancer, and cancer stem cells. Nature. 414:105–111. 2001. View Article : Google Scholar : PubMed/NCBI
6	Siddique HR and Saleem M: Role of BMI1, a stem cell factor, in cancer recurrence and chemoresistance: preclinical and clinical evidences. Stem Cells. 30:372–378. 2012. View Article : Google Scholar : PubMed/NCBI
7	Sugihara E and Saya H: Complexity of cancer stem cells. Int J Cancer. 132:1249–1259. 2013. View Article : Google Scholar : PubMed/NCBI
8	Kondo T: Stem cell-like cancer cells in cancer cell lines. Cancer Biomark. 3:245–250. 2007.PubMed/NCBI
9	Wu C and Alman BA: Side population cells in human cancers. Cancer Lett. 268:1–9. 2008. View Article : Google Scholar
10	Park IK, Morrison SJ and Clarke MF: Bmi1, stem cells, and senescence regulation. J Clin Invest. 113:175–179. 2004. View Article : Google Scholar : PubMed/NCBI
11	Jacobs JJ, Kieboom K, Marino S, DePinho RA and van Lohuizen M: The oncogene and Polycomb-group gene bmi-1 regulates cell proliferation and senescence through the ink4a locus. Nature. 397:164–168. 1999. View Article : Google Scholar : PubMed/NCBI
12	Park IK, Qian D, Kiel M, et al: Bmi-1 is required for maintenance of adult self-renewing haematopoietic stem cells. Nature. 423:302–305. 2003. View Article : Google Scholar : PubMed/NCBI
13	Siddique HR, Parray A, Tarapore RS, et al: BMI1 polycomb group protein acts as a master switch for growth and death of tumor cells: regulates TCF4-transcriptional factor-induced BCL2 signaling. PLoS One. 8:e606642013. View Article : Google Scholar : PubMed/NCBI
14	Fan X, Chen X, Deng W, Zhong G, Cai Q and Lin T: Up-regulated microRNA-143 in cancer stem cells differentiation promotes prostate cancer cells metastasis by modulating FNDC3B expression. BMC Cancer. 13:612013. View Article : Google Scholar : PubMed/NCBI
15	Ponti D, Costa A, Zaffaroni N, et al: Isolation and in vitro propagation of tumorigenic breast cancer cells with stem/progenitor cell properties. Cancer Res. 65:5506–5511. 2005. View Article : Google Scholar : PubMed/NCBI
16	Tang C, Ang BT and Pervaiz S: Cancer stem cell: target for anti-cancer therapy. FASEB J. 21:3777–3785. 2007. View Article : Google Scholar : PubMed/NCBI
17	Ning ZF, Huang YJ, Lin TX, et al: Subpopulations of stem-like cells in side population cells from the human bladder transitional cell cancer cell line T24. J Int Med Res. 37:621–630. 2009. View Article : Google Scholar : PubMed/NCBI
18	Molofsky AV, He S, Bydon M, Morrison SJ and Pardal R: Bmi-1 promotes neural stem cell self-renewal and neural development but not mouse growth and survival by repressing the p16^Ink4a and p19^Arf senescence pathways. Genes Dev. 19:1432–1437. 2005. View Article : Google Scholar : PubMed/NCBI
19	Cetin I and Topcul M: Cancer stem cells in oncology. J BUON. 17:644–648. 2012.PubMed/NCBI
20	Moserle L, Ghisi M, Amadori A and Indraccolo S: Side population and cancer stem cells: therapeutic implications. Cancer Lett. 288:1–9. 2010. View Article : Google Scholar : PubMed/NCBI
21	Ho MM, Ng AV, Lam S and Hung JY: Side population in human lung cancer cell lines and tumors is enriched with stem-like cancer cells. Cancer Res. 67:4827–4833. 2007. View Article : Google Scholar : PubMed/NCBI
22	Oates JE, Grey BR, Addla SK, et al: Hoechst 33342 side population identification is a conserved and unified mechanism in urological cancers. Stem Cells Dev. 18:1515–1522. 2009. View Article : Google Scholar : PubMed/NCBI
23	Zhou S, Schuetz JD, Bunting KD, et al: The ABC transporter Bcrp1/ABCG2 is expressed in a wide variety of stem cells and is a molecular determinant of the side-population phenotype. Nat Med. 7:1028–1034. 2001. View Article : Google Scholar : PubMed/NCBI
24	Hepburn AC, Veeratterapillay R, Williamson SC, et al: Side population in human non-muscle invasive bladder cancer enriches for cancer stem cells that are maintained by MAPK signalling. PLoS One. 7:e506902012. View Article : Google Scholar : PubMed/NCBI
25	Stingl J, Eirew P, Ricketson I, et al: Purification and unique properties of mammary epithelial stem cells. Nature. 439:993–997. 2006.PubMed/NCBI
26	Mitsutake N, Iwao A, Nagai K, et al: Characterization of side population in thyroid cancer cell lines: cancer stem-like cells are enriched partly but not exclusively. Endocrinology. 148:1797–1803. 2007. View Article : Google Scholar : PubMed/NCBI
27	Triel C, Vestergaard ME, Bolund L, Jensen TG and Jensen UB: Side population cells in human and mouse epidermis lack stem cell characteristics. Exp Cell Res. 295:79–90. 2004. View Article : Google Scholar : PubMed/NCBI
28	Broadley KW, Hunn MK, Farrand KJ, et al: Side population is not necessary or sufficient for a cancer stem cell phenotype in glioblastoma multiforme. Stem Cells. 29:452–461. 2011. View Article : Google Scholar : PubMed/NCBI
29	Lessard J and Sauvageau G: Bmi-1 determines the proliferative capacity of normal and leukaemic stem cells. Nature. 423:255–260. 2003. View Article : Google Scholar : PubMed/NCBI
30	Chiba T, Miyagi S, Saraya A, et al: The polycomb gene product BMI1 contributes to the maintenance of tumor-initiating side population cells in hepatocellular carcinoma. Cancer Res. 68:7742–7749. 2008. View Article : Google Scholar : PubMed/NCBI
31	Liu S, Dontu G, Mantle ID, et al: Hedgehog signaling and Bmi-1 regulate self-renewal of normal and malignant human mammary stem cells. Cancer Res. 66:6063–6071. 2006. View Article : Google Scholar : PubMed/NCBI
32	Proctor E, Waghray M, Lee CJ, et al: Bmi1 enhances tumorigenicity and cancer stem cell function in pancreatic adenocarcinoma. PLoS One. 8:e558202013. View Article : Google Scholar : PubMed/NCBI
33	Qin ZK, Yang JA, Ye YL, et al: Expression of Bmi-1 is a prognostic marker in bladder cancer. BMC Cancer. 9:612009. View Article : Google Scholar : PubMed/NCBI
34	Liang W, Zhu D, Cui X, et al: Knockdown BMI1 expression inhibits proliferation and invasion in human bladder cancer T24 cells. Mol Cell Biochem. 382:283–291. 2013. View Article : Google Scholar : PubMed/NCBI
35	Yin T, Wei H, Leng Z, et al: Bmi-1 promotes the chemoresistance, invasion and tumorigenesis of pancreatic cancer cells. Chemotherapy. 57:488–496. 2011. View Article : Google Scholar : PubMed/NCBI
36	Wang E, Bhattacharyya S, Szabolcs A, et al: Enhancing chemotherapy response with Bmi-1 silencing in ovarian cancer. PLoS One. 6:e179182011. View Article : Google Scholar : PubMed/NCBI
37	Falso MJ, Buchholz BA and White RW: Stem-like cells in bladder cancer cell lines with differential sensitivity to cisplatin. Anticancer Res. 32:733–738. 2012.PubMed/NCBI
38	Zhang Y, Wang Z, Yu J, et al: Cancer stem-like cells contribute to cisplatin resistance and progression in bladder cancer. Cancer Lett. 322:70–77. 2012. View Article : Google Scholar : PubMed/NCBI
39	Molofsky AV, Pardal R, Iwashita T, Park IK, Clarke MF and Morrison SJ: Bmi-1 dependence distinguishes neural stem cell self-renewal from progenitor proliferation. Nature. 425:962–967. 2003. View Article : Google Scholar : PubMed/NCBI
40	Biehs B, Hu JK, Strauli NB, et al: BMI1 represses Ink4a/Arf and Hox genes to regulate stem cells in the rodent incisor. Nat Cell Biol. 15:846–852. 2013. View Article : Google Scholar : PubMed/NCBI
41	Fasano CA, Dimos JT, Ivanova NB, Lowry N, Lemischka IR and Temple S: shRNA knockdown of Bmi-1 reveals a critical role for p21-Rb pathway in NSC self-renewal during development. Cell Stem Cell. 1:87–99. 2007. View Article : Google Scholar : PubMed/NCBI
42	Xu CR, Lee S, Ho C, et al: Bmi1 functions as an oncogene independent of Ink4A/Arf repression in hepatic carcinogenesis. Mol Cancer Res. 7:1937–1945. 2009. View Article : Google Scholar : PubMed/NCBI
43	Douglas D, Hsu JH, Hung L, et al: BMI-1 promotes Ewing sarcoma tumorigenicity independent of CDKN2A repression. Cancer Res. 68:6507–6515. 2008. View Article : Google Scholar : PubMed/NCBI