Blockage of RelB expression by gene silencing enhances the radiosensitivity of androgen‑independent prostate cancer cells

Zhu,Heng‑Cheng; Qiu,Tao; Dan,Chao; Liu,Xiu‑Heng; Hu,Chun‑Hai

doi:10.3892/mmr.2014.2857

Blockage of RelB expression by gene silencing enhances the radiosensitivity of androgen‑independent prostate cancer cells

Authors:
- Heng‑Cheng Zhu
- Tao Qiu
- Chao Dan
- Xiu‑Heng Liu
- Chun‑Hai Hu
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Affiliations: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
Published online on: November 4, 2014 https://doi.org/10.3892/mmr.2014.2857
Pages: 1167-1173

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Abstract

Levels of the nuclear factor‑kappa B (NF‑κB) alternative pathway member RelB have been shown to correlate with the effect of radiation therapy in prostate cancer. RelB expression was evaluated by immunohistochemistry in normal prostate, benign prostate hyperplasia and prostate cancer specimens. RM‑1 cells were pretreated with RelB siRNA prior to radiation therapy, and RelB expression in cytoplasmic and nuclear extracts was detected by real‑time polymerase chain reaction and western blot analysis. The apoptotic rates of experimental RM‑1 cell groups were assessed by flow cytometry. A clonogenic growth array was used to evaluate the radiosensitivity of RM‑1 cell groups. The NF‑κB family member RelB was expressed at a high level in prostate cancer specimens. Compared with irradiated control cells, RM‑1 cells transfected with RelB siRNA and treated with radiation therapy demonstrated a significant downregulation of RelB expression in the cytoplasm and nucleus. Notably, flow cytometry revealed that pretreatment of RM‑1 cells with RelB siRNA enhanced the apoptotic rate in response to radiation therapy compared with controls. Clonogenic growth assay results revealed enhanced radiosensitivity of RelB siRNA cells at various dosage points compared with control groups. Blockage of the alternative NF‑κB pathway via RelB silencing is a promising approach to enhance the radiosensitivity of prostate cancer.

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1	Brawley OW: Prostate cancer epidemiology in the United States. World J Urol. 30:195–200. 2012. View Article : Google Scholar : PubMed/NCBI
2	Shao Q, Ouyang J, Fan Y, et al: Prostate cancer in the senior men from rural areas in east district of China: contemporary management and 5-year outcomes at multi-institutional collaboration. Cancer Lett. 315:170–177. 2012. View Article : Google Scholar
3	Fitzgerald TJ, Wang T, Goel HL, et al: Prostate carcinoma and radiation therapy: therapeutic treatment resistance and strategies for targeted therapeutic intervention. Expert Rev Anticancer Ther. 8:967–974. 2008. View Article : Google Scholar : PubMed/NCBI
4	Criswell T, Leskov K, Miyamoto S, et al: Transcription factors activated in mammalian cells after clinically relevant doses of ionizing radiation. Oncogene. 22:5813–5827. 2003. View Article : Google Scholar : PubMed/NCBI
5	Seo SI, Song SY, Kang MR, et al: Immunohistochemical analysis of NF-kappaB signaling proteins IKKepsilon, p50/p105, p52/p100 and RelA in prostate cancers. APMIS. 117:623–628. 2009. View Article : Google Scholar : PubMed/NCBI
6	Perkins ND and Gilmore TD: Good cop, bad cop: the different faces of NF-κB. Cell Death Differ. 13:759–772. 2006. View Article : Google Scholar : PubMed/NCBI
7	Enzler T, Sano Y, Choo MK, et al: Cell-selective inhibition of NF-κB signaling improves therapeutic index in a melanoma chemotherapy model. Cancer Discov. 1:496–507. 2011. View Article : Google Scholar
8	Umezawa K: Possible role of peritoneal NF-κB in peripheral inflammation and cancer: lessons from the inhibitor DHMEQ. Biomed Pharmacother. 65:252–259. 2011. View Article : Google Scholar : PubMed/NCBI
9	Lessard L, Begin LR, Gleave ME, et al: Nuclear localisation of nuclear factor-kappaB transcription factors in prostate cancer: an immunohistochemical study. Br J Cancer. 93:1019–1023. 2005. View Article : Google Scholar : PubMed/NCBI
10	Murley JS, Kataoka Y and Cao D: Delayed radioprotection by NFkappaB-mediated induction of Sod2 (MnSOD) in SA-NH tumor cells after exposure to clinically used thiol-containing drugs. Radiat Res. 162:536–546. 2004. View Article : Google Scholar : PubMed/NCBI
11	Xu Y, Josson S, Fang F, Oberley TD, et al: RelB enhances prostate cancer growth: implications for the role of the nuclear factor-kappaB alternative pathway in tumorigenicity. Cancer Res. 69:3267–3271. 2009. View Article : Google Scholar : PubMed/NCBI
12	Heng-cheng TT, Liu XH, Kuang YU, et al: Construction and identification of mouse RelB siRNA-expressing lentiviral vectors. Sci Res Essays. 6:777–783. 2011.
13	Chendil D, Das A, Dey D, et al: Par-4, a pro-apoptotic gene, inhibits radiation-induced NF kappa B activity and Bcl-2 expression leading to induction of radiosensitivity in human prostate cancer cells PC-3. Cancer Biol Ther. 1:152–160. 2002. View Article : Google Scholar : PubMed/NCBI
14	Okera M, Bae K, Bernstein E, et al: Evaluation of nuclear factor kappaB and chemokine receptor CXCR4 co-expression in patients with prostate cancer in the Radiation Therapy Oncology Group (RTOG) 8610. BJU Int. 108:E51–E58. 2011. View Article : Google Scholar
15	Holley AK, Xu Y, St Clair DK and St Clair WH: RelB regulates manganese superoxide dismutase gene and resistance to ionizing radiation of prostate cancer cells. Ann N Y Acad Sci. 1201:129–136. 2010. View Article : Google Scholar : PubMed/NCBI
16	Hanahan D and Weinberg RA: Hallmarks of cancer: the next generation. Cell. 144:646–674. 2011. View Article : Google Scholar : PubMed/NCBI
17	Watson C, Miller DA, Chin-Sinex H, et al: Suppression of NF-kappaB activity by parthenolide induces X-ray sensitivity through inhibition of split-dose repair in TP53 null prostate cancer cells. Radiat Res. 171:389–396. 2009. View Article : Google Scholar : PubMed/NCBI
18	Bischoff P, Altmeyer A and Dumont F: Radiosensitising agents for the radiotherapy of cancer: advances in traditional and hypoxia targeted radiosensitisers. Expert Opin Ther Pat. 19:643–662. 2009. View Article : Google Scholar : PubMed/NCBI
19	Carlson DJ, Yenice KM and Orton CG: Tumor hypoxia is an important mechanism of radioresistance in hypofractionated radiotherapy and must be considered in the treatment planning process. Med Phys. 38:6347–6350. 2011. View Article : Google Scholar : PubMed/NCBI
20	Yacoub A, Miller A, Caron RW, et al: Radiotherapy-induced signal transduction. Endocr Relat Cancer. 13:S99–S114. 2006. View Article : Google Scholar
21	Koterba K, Beckman MJ and Gewirtz DA: A switch between cytoprotective and cytotoxic autophagy in the radiosensitization of breast tumor cells by chloroquine and vitamin D. Horm Cancer. 2:272–285. 2011. View Article : Google Scholar : PubMed/NCBI
22	Klokov D, Criswell T, Leskov KS, Araki S, Mayo L and Boothman DA: IR-inducible clusterin gene expression: a protein with potential roles in ionizing radiation-induced adaptive responses, genomic instability, and bystander effects. Mutat Res. 568:97–110. 2004. View Article : Google Scholar : PubMed/NCBI
23	Simon EL, Goel HL, Teider N, et al: High dose fractionated ionizing radiation inhibits prostate cancer cell adhesion and beta(1) integrin expression. Prostate. 64:83–91. 2005. View Article : Google Scholar : PubMed/NCBI
24	Tang CH and Tsai CC: CCL2 increases MMP-9 expression and cell motility in human chondrosarcoma cells via the Ras/Raf/MEK/ERK/NF-κB signaling pathway. Biochem Pharmacol. 83:335–344. 2012. View Article : Google Scholar
25	Zhu L, Zhu B, Yang L, Zhao X, Jiang H and Ma F: RelB regulates Bcl-xl expression and the irradiation-induced apoptosis of murine prostate cancer cells. Biomed Rep. 3:354–358. 2014.
26	Umemura N, Zhu J, Mburu YK, et al: Defective NF-κB signaling in metastatic head and neck cancer cells leads to enhanced apoptosis by double-stranded RNA. Cancer Res. 72:45–55. 2012. View Article : Google Scholar :
27	Pradhan M, Baumgarten SC, Bembinster LA, et al: CBP mediates NF-κB-dependent histone acetylation and estrogen receptor recruitment to an estrogen response element in the BIRC3 promoter. Mol Cell Biol. 32:569–575. 2012. View Article : Google Scholar :
28	Josson S, Xu Y, Fang F, et al: RelB regulates manganese superoxide dismutase gene and resistance to ionizing radiation of prostate cancer cells. Oncogene. 25:1554–1559. 2006. View Article : Google Scholar
29	Xu Y, Fang F, St Clair DK, et al: Suppression of RelB-mediated manganese superoxide dismutase expression reveals a primary mechanism for radiosensitization effect of 1alpha,25-dihydroxyvitamin D(3) in prostate cancer cells. Mol Cancer Ther. 6:2048–2056. 2007. View Article : Google Scholar : PubMed/NCBI
30	Xu Y, Fang F, St Clair DK, et al: SN52, a novel nuclear factor-kappaB inhibitor, blocks nuclear import of RelB:p52 dimer and sensitizes prostate cancer cells to ionizing radiation. Mol Cancer Ther. 7:2367–2376. 2008. View Article : Google Scholar : PubMed/NCBI
31	Reuter S, Charlet J, Juncker T, et al: Effect of curcumin on nuclear factor kappaB signaling pathways in human chronic myelogenous K562 leukemia cells. Ann N Y Acad Sci. 1171:436–447. 2009. View Article : Google Scholar : PubMed/NCBI