Nanog siRNA plus Cisplatin may enhance the sensitivity of chemotherapy in esophageal cancer.

BACKGROUND: Cancer stem cells are regarded as the origin of tumors that can proliferate, relapse, and metastasize. Nanog, with its capacity to maintain the pluripotency and regulate proliferation and prevent differentiation, is one of the most important core markers of cancer stem cells. Studying the role of Nanog in esophageal squamous cell carcinoma (ESCC), therefore, has important implications. METHODS: In the present study, we first detected the expression of Nanog in the ESCC and cell lines by RT-PCR, immunofluorescence, and immunohistochemisty. Then, we used small interfering RNA (siRNA) to block Nanog expression while evaluating the effect of Nanog siRNA on cell apoptosis and the combined effects with Cisplatin in ESCC cell lines. RESULTS: The results showed that both mRNA and protein-level Nanog are overexpressed in ESCC tissues compared with their normal counterparts, and the increased occurrence of Nanog expression was positively correlated with TNM stages and histopathological differentiation of ESCC patients (p < 0.01). At the same time, Nanog siRNA efficiently decreased Nanog expression and induced cell apoptosis. Treatment with Nanog siRNA in combination with Cisplatin, therefore, enhanced chemosensitivity. CONCLUSION: The present study's results suggest that detecting Nanog might be helpful for diagnosing ESCC, and Nanog siRNA combined with Cisplatin may be a feasible strategy to enhance the sensitivity of chemotherapy in patients with ESCC.