关键词: 5-氮杂胞苷, 食管癌, Notch1信号通路

Abstract: Background and purpose: 5-Azacytidine(5-azaC) is a DNA methyltransferase inhibitor, and has been used to treat many kinds of malignant tumors. However, studies on the role of 5-azaC in esophageal cancer are insufficient. Evading apoptosis is a major feature of tumors and also a hot spot for anti-tumor therapy. Notch1 signaling pathway is one of the most important pathways involved in initiation and development of esophageal cancer, and is closely related to cell proliferation, invasion and apoptosis. This study aimed to investigate the influence of 5-azaC on cell apoptosis and Notch1 signaling pathway in esophageal cell lines, so as to explore the possible mechanism of treatment with 5-azaC. Methods: TE-1 and OE33 cell lines were treated with 5-azaC in a concentration of 50 μmol/L and inhibitory effects of 5-azaC in esophageal cell lines were estimated using cell counting kit-8 (CCK-8). Then cell morphology was visualized using optical microscopy. Flow cytometry and Western blot were used to determine apoptotic rate and to analyze expression of B-cell lymphoma-extra large (BCL-XL), an anti-apoptosis protein, respectively. And finally, realtime fluorescent quantitative polymerase chain reaction (RTFQ-PCR) and Western blot were employed to explore expression changes of Notch1 and Notch intracellular domain (NICD). Results: 5-AzaC was able to induce apoptosis, and had a remarkable inhibitory effect on esophageal squamous carcinoma TE-1 and adenocarcinoma cell line OE33. Increased mRNA expression of Notch1 was observed following treatment with 5-azaC, while protein expression of Notch1 was unchanged and NICD showed significant decline in TE-1 and OE33 cell lines. Conclusion: 5-AzaC has strong apoptosis-promoting effect on both esophageal squamous carcinoma TE-1 and adenocarcinoma cell line OE33, and the mechanism may be related to the inhibition of Notch1 signaling pathway via downregulating NICD protein.

Key words: 5-Azacytidine, Esophageal cancer, Notch1 signaling pathway