s cellular processes.[@CIT0004] It has been reported that there are several lncRNAs involved in cervical cancer development.[@CIT0005]--[@CIT0007] LncRNAs play a role in the process of apoptosis of cervical cancer cells, tumor invasion and metastasis. So far, only a small fraction of lncRNA has been characterized in detail.[@CIT0008] Some lncRNAs regulate important cancer processes, including proliferation, migration, and invasion and drug resistance.[@CIT0009] More lncRNAs that affect cancer-related gene expression still need to be identified.

Highly upregulated in liver cancer (HULC) is a lncRNA that has recently been identified as a key regulator in the progression of various cancers.[@CIT0010] Wang et al revealed that the expression of HULC was upregulated in cervical cancer, and associated with overall survival,[@CIT0011] however, the effect and regulatory mechanism of HULC on proliferation, migration and invasion of cervical cancer cells remain unclear. MicroRNA-218 (miR-218) is a tumor-suppressive miRNA in cancers. MiR-218 was downregulated in cervical cancer, and miR-218 overexpression was found to inhibit cervical cancer cell viability, cell growth and metastasis, and promote apoptosis.[@CIT0012],[@CIT0013] Bioinformatics using miRanda predicted that HULC and miR-218 have partially complementary sequences, suggesting that HULC may function as a "miRNA sponge" of miR-218. The prediction of target genes using TargetScan showed that there were binding sites between miR-218 and 3ʹ-UTR of the oncogenic tumor protein D52 (TPD52) mRNA.[@CIT0014] Therefore, we speculated that HULC might competitively bind with miR-218 to regulate the TPD52 expression. In the current study, we aimed to examine the role and molecular mechanisms of HULC in regulating cervical cancer cell behavior.

Materials and Methods {#S0002}
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Cell Lines and Cell Culture {#S0002-S2001}
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Human cervical epithelial cells (H8 cells) and cervical cancer cells (HeLa, SiHa, CaSki and C-33A cells) purc