ECRG4 acts as a tumor suppressor and as a determinant of chemotherapy resistance in human nasopharyngeal carcinoma
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Human nasopharyngeal carcinoma (NPC) is a malignant type of cancer with an increasing incidence. As yet, however, molecular biomarkers with a strong diagnostic impact and a major therapeutic promise have remained elusive. Here, we identified the esophageal carcinoma related gene 4 (ECRG4) as a novel candidate tumor suppressor gene and a promising therapeutic target for NPC.
RT-PCR, Western blotting, methylation-specific PCR and bisulfite sequencing were performed to assess the expression and methylation status of the ECRG4 gene in primary NPC samples, NPC-derived cell lines and patient-derived peripheral blood samples. The NPC-derived cell line CNE1 was selected for treatment with a methylation inhibitor to restore ECRG4 expression. In addition, cell proliferation, invasion and colony formation assays were performed to assess the inhibitory effects of exogenous ECRG4 expression in CNE1 cells.
Down-regulated ECRG4 expression was found to occur in 82.5 % (33/40) of the primary NPC biopsies tested. This down-regulation was significantly correlated with its tumor-specific promoter methylation status (72.5 %, 29/40) and was also observed in the matching peripheral blood samples from the NPC patients (57.5 %, 23/40). Pharmacologic demethylation through 5-aza-dC treatment led to gene reactivation in ECRG4 methylated and silenced NPC cell lines. Moreover, exogenous expression of ECRG4 in the CNE1 cell line strongly inhibited its growth and invasive capacities, as well as its enhanced chemosensitivity to cisplatin through autophagy induction.
Our data suggest that methylation-mediated suppression of the ECRG4 gene occurs frequently in NPC and that restoration of its expression may have therapeutic benefits.
KeywordsECRG4 Tumor suppressor gene DNA methylation Nasopharyngeal carcinoma Cancer surveillance
We thank Mr. Zhen Zhang (Department of Biochemistry and Molecular Biology, University of Kansas Medical Center) for his careful reading of this manuscript and kind suggestions. This work was supported by the Science and Technology Planning Project of Henan Province, China (142102310464), the 2015 Annual Natural Science Foundation of Luohe Medical College (Y.-J. You), the Natural Science Foundation of Hubei Province (2014CFC1154), and the Foundation of Medical College of Hubei University of Arts and Science (YXKY 201402).
Conflicts of Interest
The authors have no conflict of interest.
- 4.Y. You, W. Yang, Z. Wang, H. Zhu, H. Li, C. Lin, Y. Ran, Promoter hypermethylation contributes to the frequent suppression of the CDK10 gene in human nasopharyngeal carcinomas. Cell Oncol. 36, 323–331 (2013)Google Scholar
- 5.A. Geurts van Kessel. The cancer genome: from structure to function. Cell Oncol. 37, 155–165 (2014)Google Scholar
- 6.B. Ramaswamy, S. Majumder, S.K. Roy, H. Ghoshal, J. Kutay, J. Datta, M. Younes, C.L. Shapiro, T. Motiwala, S.T. Jacob, Estrogen-mediated suppression of the gene encoding protein tyrosine phosphatase PTPRO in human breast cancer: mechanism and role in tamoxifen sensitivity. Mol Endocrinol. 23, 176–187 (2009)CrossRefPubMedCentralPubMedGoogle Scholar
- 10.T. Su, H. Liu, S. Lu, Cloning and identification of cDNA fragments related to human esophageal cancer. China J Oncol. 20, 254–257 (1998)Google Scholar
- 14.A.M. Gonzalez, S. Podvin, S.Y. Lin, M.C. Miller, H. Botfield, W.E. Leadbeater, A. Roberton, X. Dang, S.E. Knowling, E. Cardenas-Galindo, J.E. Donahue, E.G. Stopa, C.E. Johanson, R. Coimbra, B.P. Eliceiri, A. Baird, Ecrg4 expression and its product augurin in the choroid plexus: impact on fetal brain development, cerebrospinal fluid homeostasis and neuroprogenitor cell response to CNS injury. Fluids Barriers CNS. 8, 6 (2011)CrossRefPubMedCentralPubMedGoogle Scholar
- 17.Y. Mori, H. Ishiguro, Y. Kuwabara, M. Kimura, A. Mitsui, H. Kurehara, R. Mori, K. Tomoda, R. Ogawa, T. Katada, K. Harata, Y. Fujii, Expression of ECRG4 is an independent prognostic factor for poor survival in patients with esophageal squamous cell carcinoma. Oncol Rep. 18, 981–985 (2007)PubMedGoogle Scholar
- 23.P. Ulivi, R. Silvestrini, Role of quantitative and qualitative characteristics of free circulating DNA in the management of patients with non-small cell lung cancer. Cell Oncol. 36, 439–448 (2013)Google Scholar
- 32.I.A. Voutsadakis, The chemosensitivity of testicular germ cell tumors. Cell Oncol. 37, 79–94 (2014)Google Scholar
- 34.M.J. Nyhan, T.R. O'Donovan, B. Elzinga, L.C. Crowley, G.C. O'Sullivan, S.L. McKenna, The BH3 mimetic HA14-1 enhances 5-fluorouracil-induced autophagy and type II cell death in oesophageal cancer cells. Br J Cancer. 106, 711–718 (2012)Google Scholar
- 36.Y. Wei, T. Kadia, W. Tong, M. Zhang, Y. Jia, H. Yang, Y. Hu, F.P. Tambaro, J. Viallet, S. O'Brien, G. Garcia-Manero, The combination of a histone deacetylase inhibitor with the Bcl-2 homology domain-3 mimetic GX15-070 has synergistic antileukemia activity by activating both apoptosis and autophagy. Clin. Cancer Res. 16, 3923–3932 (2010)CrossRefPubMedCentralPubMedGoogle Scholar
- 43.C.E. Zois, M.I. Koukourakis. Radiation-induced autophagy in normal and cancer cells: towards novel cytoprotection and radio-sensitization policies? Autophagy 5, 442–450 (2009)