Cisplatin (DDP)-based adjuvant chemotherapy is widely used for the treatment of esophageal cancer. However, DDP resistance has become more common and thus new approaches are required to be explored. Cisplatin was used to induce autophagy in the human esophageal cancer cell line, EC9706 cells, and the effect of autophagy on the survival of EC9706 cells was investigated using an autophagy inhibitor 3-MA. Cell viability was measured by CCK8 assay. Apoptosis and cell cycle were detected by flow cytometry. Monodansylcadaverine (MDC) was used to detect autophagy. Western blotting assay was used to investigate the molecular changes that occurred in the course of treatment. DDP inhibited cell proliferation, induced cell death and cell cycle arrest at S phage. Moreover, autophagy was activated through class III PI3K pathway. The expression of autophagy-related Beclin1 and LC3-I was up-regulated and part of LC3-I was converted into LC3-II. However, after the combination treatment of 3-MA and DDP, the cell inhibitory rate increased; the apoptosis rate and the numbers of cells in S phase also increased. Furthermore, the accumulation of autophagic vacuoles was decreased; the expression of Beclin1 and LC3 was significantly down-regulated and the release of cytochrome c was decreased. DDP-induced apoptosis in EC9706 cells can be enhanced by the inhibitor of autophagy, 3-MA. Autophagy might play a role as a self-protective mechanism in DDP-treated esophageal cancer cells, and its inhibition could be a novel strategy for the adjuvant chemotherapy of esophageal cancer.
Kroemer G, et al. Classification of cell death: recommendations of the nomenclature committee on cell death. Cell Death Differ. 2005;12:1463–7.PubMedCrossRefGoogle Scholar
Li J, et al. Inhibition of autophagy by 3-MA enhances the effect of 5-FU-induced apoptosis in colon cancer cells. Ann Surg Oncol. 2009;16:761–71.PubMedCrossRefGoogle Scholar
Lomonaco SL, et al. The induction of autophagy by gamma-radiation contributes to the radioresistance of glioma stem cells. Int J Cancer. 2009;125:717–22.PubMedCrossRefGoogle Scholar
Chen Y, Lu Y, Lu C, Zhang L. Beclin-1 expression is a predictor of clinical outcome in patients with esophageal squamous cell carcinoma and correlated to hypoxia-inducible factor (HIF)-1alpha expression. Pathol Oncol Res. 2009. doi: 10.1007/s12253-008-9143-8.
Munafo DB, Colombo MI. A novel assay to study autophagy: regulation of autophagosome vacuole size by amino acid deprivation. J Cell Sci. 2001;114:3619–29.PubMedGoogle Scholar
Biederbick A, Kern HF, Elsasser HP. Monodansylcadaverine (MDC) is a specific in vivo marker for autophagic vacuoles. Eur J Cell Biol. 1995;66:3–14.PubMedGoogle Scholar
Kartalou M, Essigmann JM. Mechanisms of resistance to cisplatin. Mutat Res. 2001;478:23–43.PubMedGoogle Scholar
Seglen PO, Gordon PB. 3-Methyladenine: specific inhibitor of autophagic/lysosomal protein degradation in isolated rat hepatocytes. Proc Natl Acad Sci USA. 1982;79:1889–92.PubMedCrossRefGoogle Scholar
Lum JJ, et al. Growth factor regulation of autophagy and cell survival in the absence of apoptosis. Cell. 2005;120:237–48.PubMedCrossRefGoogle Scholar
Herman-Antosiewicz A, Johnson DE, Singh SV. Sulforaphane causes autophagy to inhibit release of cytochrome c and apoptosis in human prostate cancer cells. Cancer Res. 2006;66:5828–35.PubMedCrossRefGoogle Scholar
Nishikawa T, et al. Inhibition of autophagy potentiates sulforaphane—induced apoptosis in human colon cancer cells. Ann Surg Oncol. 2009 [Epub ahead of print]. doi: 10.1245/s10434-009-0696-x.
Degenhardt K, et al. Autophagy promotes tumor cell survival and restricts necrosis, inflammation, and tumorigenesis. Cancer Cell. 2006;10:51–64.PubMedCrossRefGoogle Scholar
Karantza-Wadsworth V, et al. Autophagy mitigates metabolic stress and genome damage in mammary tumorigenesis. Genes Dev. 2007;21:1621–35.PubMedCrossRefGoogle Scholar
Katayama M, Kawaguchi T, Berger MS, Pieper RO. DNA damaging agent-induced autophagy produces a cytoprotective adenosine triphosphate surge in malignant glioma cells. Cell Death Differ. 2007;14:548–58.PubMedCrossRefGoogle Scholar
Pan J, et al. Autophagy induced by farnesyltransferase inhibitors in cancer cells. Cancer Biol Ther. 2008;7:1679–84.PubMedCrossRefGoogle Scholar
Park MA, et al. Vorinostat and sorafenib increase ER stress, autophagy and apoptosis via ceramide-dependent CD95 and PERK activation. Cancer Biol Ther. 2008;7:1648–62.PubMedCrossRefGoogle Scholar
de Bruin EC, Medema JP. Apoptosis and non-apoptotic death in cancer development and treatment response. Cancer Treat Rev. 2008;34:737–49.PubMedCrossRefGoogle Scholar
Maiuri MC, et al. Control of autophagy by oncogenes and tumor suppressor genes. Cell Death Differ. 2009;16:87–93.PubMedCrossRefGoogle Scholar
Ding WX, et al. Differential effects of endoplasmic reticulum stress-induced autophagy on cell survival. J Biol Chem. 2007;282:4702–10.PubMedCrossRefGoogle Scholar
Wu YC, et al. Inhibition of macroautophagy by bafilomycin A1 lowers proliferation and induces apoptosis in colon cancer cells. Biochem Biophys Res Commun. 2009;382:451–6.PubMedCrossRefGoogle Scholar
Yang C, et al. Inhibition of autophagy induced by overexpression of mda-7/interleukin-24 strongly augments the antileukemia activity in vitro and in vivo. Cancer Gene Ther. 2009 [Epub ahead of print]. doi: 10.1038/cgt.2009.57.
Chen N, Karantza-Wadsworth V. Role and regulation of autophagy in cancer. Biochim Biophys Acta. 2009;1793:1516–23.PubMedCrossRefGoogle Scholar
Iwamaru A, et al. Silencing mammalian target of rapamycin signaling by small interfering RNA enhances rapamycin-induced autophagy in malignant glioma cells. Oncogene. 2007;26:1840–51.PubMedCrossRefGoogle Scholar
Takeuchi H, et al. Synergistic augmentation of rapamycin-induced auto-phagy in malignant glioma cells by phosphatidylinositol 3-kinase protein kinase B inhibitors. Cancer Res. 2005;65:3336–46.PubMedGoogle Scholar