Long non-coding RNA THOR promotes ovarian Cancer cells progression via IL-6/STAT3 pathway

BACKGROUND: Ovarian cancer (OC) is one of the most common malignant tumors in the world. The prognosis of OC remains poor due to the advanced stage and distant metastasis at the time of diagnosis. Recently, a novel lncRNA, THOR (testis-associated highly conserved oncogenic long non-coding RNA), was characterized in human cancers and shown to exhibit an oncogenic role. However, the role of THOR in OC remains unclear. METHODS: RT-PCR and western blot analysis were used to detect the expression of THOR, p-STAT3 and IL-6. The impact of THOR on OC proliferation, metastasis and self-renewal was investigated in vitro and in vivo. The prognostic value of THOR was determined in OC patient cohorts. RESULTS: In this study, our results find that THOR is markedly upregulated in human OC tissues and predicts the poor prognosis of OC patients. Functional studies have revealed that knockdown of THOR inhibits the growth, metastasis and self-renewal of OC cells. Mechanistically, THOR drives OC cell progression via the IL-6/STAT3 signaling. Moreover, the specific STAT3 inhibitor S3I-201 or IL-6R inhibitor tocilizumab diminish the discrepancy in the growth, metastatic and self-renewal capacity between THOR-silenced OC cells and control cells, which further confirm that IL-6/STAT3 is required in THOR-driven OC cells progression. CONCLUSION: Our findings reveal that THOR could promote OC cells growth, metastasis and self-renewal by activating IL-6/STAT3 signaling and may be a good predictive factor and therapeutic target.