Poly(ADP-ribose) polymerase-1 regulates the mechanism of irradiation-induced CNE-2 human nasopharyngeal carcinoma cell autophagy and inhibition of autophagy contributes to the radiation sensitization of CNE-2 cells

Zhou,Zhi-Rui; Zhu,Xiao-Dong; Zhao,Wei; Qu,Song; Su,Fang; Huang,Shi-Ting; Ma,Jia-Ling; Li,Xiao-Yu

doi:10.3892/or.2013.2382

Poly(ADP-ribose) polymerase-1 regulates the mechanism of irradiation-induced CNE-2 human nasopharyngeal carcinoma cell autophagy and inhibition of autophagy contributes to the radiation sensitization of CNE-2 cells

Authors:
- Zhi-Rui Zhou
- Xiao-Dong Zhu
- Wei Zhao
- Song Qu
- Fang Su
- Shi-Ting Huang
- Jia-Ling Ma
- Xiao-Yu Li
View Affiliations

Affiliations: Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning 530021, P.R. China
Published online on: April 4, 2013 https://doi.org/10.3892/or.2013.2382
Pages: 2498-2506

Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )

Metrics: Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )

Cited By (CrossRef): 0 citations Loading Articles...

Abstract

The aim of the present study was to investigate the role of autophagy in response to ionizing radiation (IR) in CNE-2 human nasopharyngeal carcinoma cells and to demonstrate the function of poly(ADP-ribose) polymerase-1 (PARP-1) in the regulation of IR-induced autophagy. Microtubule-associated protein 1 light chain 3 (LC3) and poly(ADP-ribose) (PAR) were assessed using western blotting. Ultrastructural analysis was performed using transmission electron microscopy (TEM). The percentage of apoptotic cells was assessed by flow cytometry. The MTT method was used to detect cell viability of CNE-2 cells at different time points after IR. Clonogenic survival assays were used to evaluate the radiosensitivity of nasopharyngeal carcinoma cells treated with IR and IR combined with autophagy inhibitor (chloroquine phosphate), with autophagy inducer (rapamycin) or with PARP-1 inhibitor 3-amino benzamide (3AB). IR induced a massive accumulation of autophagosomes detected by TEM and intensified the conversion of cytosolic LC3-I to LC3-II. PARP-1 activation was accompanied by strong upregulation of PAR and LC3-II expression in CNE-2 cells. Compared with radiation alone, chloroquine phosphate (CDP) or 3AB combined with IR significantly decreased cell viability, as well as the autophagic ratio and LC3-II protein levels. Inhibition of autophagy increased radiation-induced apoptosis; rapamycin (RAPA) significantly decreased cell viability as well, but RAPA increased the autophagic ratio and LC3-II protein levels; induction of autophagy increased radiation-induced apoptosis. To conclude, PARP-1 regulates IR-induced autophagy, and PARP-1 inhibitor contributes to the radiation sensitization of CNE-2 cells. Blockade of autophagy with CDP enhanced the cytotoxicity of radiotherapy in CNE-2 cells. This suggests that inhibition of autophagy or PARP-1 may be used as an adjuvant therapy to treat nasopharyngeal carcinoma.

View Figures

View References

1	Wei WI and Sham JST: Nasopharyngeal carcinoma. Lancet. 365:2041–2054. 2005. View Article : Google Scholar : PubMed/NCBI
2	Feng XP, Yi H, Li MY, et al: Identification of biomarkers for predicting nasopharyngeal carcinoma response to radiotherapy by proteomics. Cancer Res. 70:3450–3462. 2010. View Article : Google Scholar : PubMed/NCBI
3	Guo Y, Zhu XD, Qu S, et al: Identification of genes involved in radioresistance of nasopharyngeal carcinoma by integrating gene ontology and protein-protein interaction networks. Int J Oncol. 40:85–92. 2012.
4	Mizushima N: Autophagy: process and function. Genes Dev. 21:2861–2873. 2007. View Article : Google Scholar
5	Mizushima N, Levine B, Cuervo AM and Klionsky DJ: Autophagy fights disease through cellular self-digestion. Nature. 451:1069–1075. 2008. View Article : Google Scholar : PubMed/NCBI
6	Degenhardt K, Mathew R, Beaudoin B, et al: Autophagy promotes tumor cell survival and restricts necrosis, inflammation, and tumorigenesis. Cancer Cell. 10:51–64. 2006. View Article : Google Scholar : PubMed/NCBI
7	Shintani T and Klionsky DJ: Autophagy in health and disease: a double-edged sword. Science. 306:990–995. 2004. View Article : Google Scholar : PubMed/NCBI
8	Komatsu M, Waguri S, Chiba T, et al: Loss of autophagy in the central nervous system causes neurodegeneration in mice. Nature. 441:880–884. 2006. View Article : Google Scholar : PubMed/NCBI
9	Hara T, Nakamura K, Matsui M, et al: Suppression of basal autophagy in neural cells causes neurodegenerative disease in mice. Nature. 441:885–889. 2006. View Article : Google Scholar : PubMed/NCBI
10	Dalby KN, Tekedereli I, Lopez-Berestein G and Ozpolat B: Targeting the prodeath and prosurvival functions of autophagy as novel therapeutic strategies in cancer. Autophagy. 6:322–329. 2010. View Article : Google Scholar : PubMed/NCBI
11	Apel A, Herr I, Schwarz H, Rodemann HP and Mayer A: Blocked autophagy sensitizes resistant carcinoma cells to radiation therapy. Cancer Res. 68:1485–1494. 2008. View Article : Google Scholar : PubMed/NCBI
12	Marx J: Autophagy: is it cancer’s friend or foe? Science. 312:1160–1161. 2006.
13	Wu WK, Coffelt SB, Cho CH, et al: The autophagic paradox in cancer therapy. Oncogene. 31:939–953. 2012. View Article : Google Scholar : PubMed/NCBI
14	Schreiber V, Dantzer F, Ame JC and de Murcia G: Poly(ADP-ribose): novel functions for an old molecule. Nat Rev Mol Cell Biol. 7:517–528. 2006. View Article : Google Scholar : PubMed/NCBI
15	Yu SW, Wang H, Poitras MF, et al: Mediation of poly(ADP-ribose) polymerase-1-dependent cell death by apoptosis-inducing factor. Science. 297:259–263. 2002. View Article : Google Scholar : PubMed/NCBI
16	Jagtap P and Szabo C: Poly(ADP-ribose) polymerase and the therapeutic effects of its inhibitors. Nat Rev Drug Discov. 4:421–440. 2005. View Article : Google Scholar : PubMed/NCBI
17	Ha HC and Snyder SH: Poly(ADP-ribose) polymerase is a mediator of necrotic cell death by ATP depletion. Proc Natl Acad Sci USA. 96:13978–13982. 1999. View Article : Google Scholar : PubMed/NCBI
18	Albert JM, Cao C, Kim KW, et al: Inhibition of poly (ADP-ribose) polymerase enhances cell death and improves tumor growth delay in irradiated lung cancer models. Clin Cancer Res. 13:3033–3042. 2007. View Article : Google Scholar
19	Hagan MP, Yacoub A and Dent P: Radiation-induced PARP activation is enhanced through EGFR-ERK signaling. J Cell Biochem. 101:1384–1393. 2007. View Article : Google Scholar : PubMed/NCBI
20	Cao C, Subhawong T, Albert JM, et al: Inhibition of mammalian target of rapamycin or apoptotic pathway induces autophagy and radiosensitizes PTEN null prostate cancer cells. Cancer Res. 66:10040–10047. 2006. View Article : Google Scholar : PubMed/NCBI
21	Chen YS, Song HX, Lu Y, et al: Autophagy inhibition contributes to radiation sensitization of esophageal squamous carcinoma cells. Dis Esophagus. 24:437–443. 2011. View Article : Google Scholar : PubMed/NCBI
22	Lomonaco SL, Finniss S, Xiang CL, et al: The induction of autophagy by gamma-radiation contributes to the radioresistance of glioma stem cells. Int J Cancer. 125:717–722. 2009. View Article : Google Scholar : PubMed/NCBI
23	Ito H, Daido S, Kanzawa T, Kondo S and Kondo Y: Radiation-induced autophagy is associated with LC3 and its inhibition sensitizes malignant glioma cells. Int J Oncol. 26:1401–1410. 2005.PubMed/NCBI
24	Paglin S, Lee NY, Nakar C, et al: Rapamycin-sensitive pathway regulates mitochondrial membrane potential, autophagy, and survival in irradiated MCF-7 cells. Cancer Res. 65:11061–11070. 2005. View Article : Google Scholar
25	Rieber M and Rieber MS: Sensitization to radiation-induced DNA damage accelerates loss of bcl-2 and increases apoptosis and autophagy. Cancer Biol Ther. 7:1561–1566. 2008. View Article : Google Scholar : PubMed/NCBI
26	Peng PL, Kuo WH, Tseng HC and Chou FP: Synergistic tumor-killing effect of radiation and berberine combined treatment in lung cancer: the contribution of autophagic cell death. Int J Radiat Oncol Biol Phys. 70:529–542. 2008. View Article : Google Scholar : PubMed/NCBI
27	Maiuri MC, Zalckvar E, Kimchi A and Kroemer G: Self-eating and self-killing: crosstalk between autophagy and apoptosis. Nat Rev Mol Cell Biol. 8:741–752. 2007. View Article : Google Scholar : PubMed/NCBI
28	Kroemer G and Levine B: Autophagic cell death: the story of a misnomer. Nat Rev Mol Cell Biol. 9:1004–1010. 2008. View Article : Google Scholar : PubMed/NCBI
29	Levine B and Yuan JY: Autophagy in cell death: an innocent convict? J Clin Invest. 115:2679–2688. 2005. View Article : Google Scholar : PubMed/NCBI
30	Galluzzi L, Aaronson SA, Abrams J, et al: Guidelines for the use and interpretation of assays for monitoring cell death in higher eukaryotes. Cell Death Differ. 16:1093–1107. 2009. View Article : Google Scholar : PubMed/NCBI
31	Huang Q and Shen HM: To die or to live: the dual role of poly(ADP-ribose) polymerase-1 in autophagy and necrosis under oxidative stress and DNA damage. Autophagy. 5:273–276. 2009. View Article : Google Scholar