Objective To detect the expression of lncRNA RP11-173C1.1 in differentiated thyroid tissue, and to investigate the effect of RP11-173C1.1 on the proliferation and invasion of thyroid papillary carcinoma cell line B-CPAP and the molecular mechanism.

Methods qRT-PCR was used to detect the expression level of RP11-173C1.1 in differentiated thyroid cancer tissues and thyroid cancer cell lines. The B-CPAP cells with the lowest expression level were used as the research object, and the RP11-173C1.1 overexpression plasmid and the negative control plasmid were transfected into the experimental group and the control group, respectively. The effects of RP11-173C1.1 on the proliferation and invasion of B-CPAP cells were detected by CCK-8 and Transwell invasion assays, respectively. The bioinformatics method predicted the mechanism of RP11-173C1.1. qRT-PCR and Western blot were used to detect the effect of RP11-173C1.1 on downstream gene expression.

Results The expression of RP11-173C1.1 was significantly lower in thyroid cancer tissues than that in adjacent tissues (P < 0.01). The expression of RP11-173C1.1 in thyroid cancer cell lines was significantly lower than that in normal thyroid follicular epithelial cells (P < 0.01). Up-regulation of RP11-173C1.1 inhibited the proliferation and invasion abilities of B-CPAP cells (both P < 0.05). RP11-173C1.1 complemented miR-376c-3p, and miR-376c-3p complemented OPCML. Up-regulation of RP11-173C1.1 reduced miR-376c-3p expression and promoted OPCML mRNA and protein expression in B-CPAP cells (all P < 0.01).

Conclusion RP11-173C1.1 is lowly expressed in differentiated thyroid carcinoma tissues and cell lines. Up-regulation of RP11-173C1.1 could inhibit the proliferation and invasion of thyroid papillary carcinoma cell line B-CPAP. The possible mechanism is down-regulating miR-376c-3p expression and up-regulating OPCML gene expression.