Serum level of lncRNA TUSC7 in patients with esophageal squamous cell carcinoma and its role in promoting tumor cell migration and invasion

Abstract

To investigate serum levels of long non-coding RNA (lncRNA) TUSC7 in patients with esophageal squamous cell carcinoma (ESCC), its association with clinicopathological parameters and its role in promoting tumor metastasis and invasion. Serum samples were collected from 60 patients with ESCC admitted between January, 2017 and May, 2019, with 60 age- and gender-matched healthy subjects as the control group. Serum level of TUSC7 in ESCC patients and its expression in 4 ESCC cell lines was detected with RT-qPCR. The association of serum TUSC7 level with the clinicopathological features of the patients was analyzed. KYSE-30 cell models with TUSC7 overexpression or knockdown were established, and the proliferation of the cells was examined with MTT assay and their migration and invasion were assessed using wound healing and Transwell assays. Western blotting was used to detect the cellular expressions of the proteins associated with epithelial-mesenchymal transition (EMT). The patients with ESCC had significantly lower serum TUSC7 level than the healthy control subjects (P < 0.05). The ESCC cell lines also expressed lower levels of TUSC7 than normal cells (P < 0.05). Serum TUSC7 level was negatively correlated with tumor staging, lymph node metastasis and infiltration (P < 0.05) but was not significantly correlated with other clinicopathological parameters in ESCC patients. In the invitro cell experiment, overexpression of TUSC7 in KYSE-30 cells significantly inhibited cell migration and invasion (P < 0.05), enhanced the expression of the EMT marker protein E-cadherin and lowered the expressions of N-cadherin, Vimentin and MMP9 (P < 0.05); knocking down TUSC7 in the cells produced the opposite effects. The down-regulation of TUSC7 expression in the serum of ESCC patients and in ESCC cell lines is associated with the metastasis of ESCC and promotes tumor cell migration and invasion by promoting EMT, indicating the potential of serum TUSC7 level as a molecular marker for diagnosis, treatment and metastasis monitoring of ESCC.