Downregulation of H19 decreases the radioresistance in esophageal squamous cell carcinoma cells

Background: Radiotherapy is one of the most common treatments for esophageal squamous cell carcinoma (ESCC). Radioresistance is a major obstacle that limits the efficacy of radiotherapy. H19 has been considered as a factor affecting radioresistance, whereas the specific mechanism of H19 in ESCC radioresistance remains to be further elucidated. Purpose: The objective of this study was to identify the relationship between H19 and radioresistance. The findings are expected to provide new insights into the treatment of radioresistant ESCC. Methods: The expression levels of H19 in ESCC was analyzed using the online database starBase. The Oncomine database was used to further verify the association between H19 expression and patient age, gender, and tumor stage. The overall survival rates of ESCC patients were analyzed using the KM plotter database. Clonogenic survival was conducted to identify the value of survival fraction. The optical density values were obtained via MTS assays. Cells migration and stemness were observed through Transwell and sphere formation assays. The expression levels of H19, miR-22-3p and WNT1 were analyzed using qPCR. Results: In our study, we firstly screened the H19 according to the online database starBase, and then the Oncomine database and KM plotter database showed that H19 expression was significantly upregulated in the ESCC tissues and associated with poor prognosis. Secondly, an ESCC radioresistant cell line, KYSE150R was established. Clonogenic survival showed that radiation decreased the value of survival fraction. MTS assays suggested that optical density values in KYSE150R cells were significantly higher than that in KYSE150 cells. Transwell and sphere formation assays showed radiation enhanced cell migration and stemness in ESCC cells. In addition, qPCR showed that H19 was upregulated in KYSE150R cells, and survival fraction assays showed that knockdown of H19 decreased the survival fraction values. MTS assays, migration and invasion assays suggested that H19 inhibited cells proliferation, migration and stemness in radioresistant KYSE150 cells. Moreover, qPCR assay showed that miR-22-3p expression levels was downregulated, but WNT1 was upregulated in KYSE150R cells as well as protein levels. Luciferase activity assay further showed that miR-22-3p inhibits the WNT1 expression. Conclusion: Our results demonstrate that H19 knockdown downregulates the WNT1 via upregulating miR-22-3p expression, which leads to the inhibition of cells proliferation, migration and stemness in the radioresistant ESCC cells.