Serine 727 phosphorylation is necessary to induce the STAT3-mediated transcription of LINC00184 in oesophageal squamous cell carcinoma

LINC00184 has been suggested to be associated with cancer prognosis and has been implicated in cancer glycolysis; however, its role in oesophageal squamous cell carcinoma (ESCC) remains poorly understood. Herein, to understand the expression and the biological roles of LINC00184 in ESCC, in situ hybridization (ISH) and quantitative PCR (qPCR) were performed to detect the expression of LINC00184 in tissue blocks and in fresh tissues, respectively. Furthermore, with an in vitro cell culture system, LINC00184 was stably knocked down in ESCC cell lines KYSE-150 and Eca109, followed by determining alterations in their proliferation and motility relative to control. To gain insight into the regulation of LINC00184, STAT3 was bioinformatically identified as a transcription factor of LINC00184, which was further corroborated by chromatin-immunoprecipitation (CHIP) assay. The dephosphorylation of STAT3 with NSC74859 was shown to be unable to suppress the expression of LINC00184 in vivo in a xenograft mouse model. Moreover, STAT3, once phosphorylated at serine 727, tended to translocate into the mitochondria to promote LINC00184 expression in ESCC cells. Together, these data strongly support the oncogenic role of LINC00184 in ESCC.