Objective: 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.
Methods: 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).
Results: 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.
Conclusions: 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.
目的: 探究长链非编码lncRNA-TUSC7在食管鳞癌患者血清中表达的临床意义并进一步评估其对食管癌细胞侵袭和转移能力的影响。
方法: 选取2017年1月~2019年5月南阳市第二人民医院和南阳市中心医院收治的60例食管鳞癌患者的血清，同时选取60例年龄、性别匹配的健康体检者血清作为对照组。采用RT-qPCR方法检测血清中TUSC7的表达，分析其与临床病理特征的关系。同时以正常食管上皮细胞为对照，检测4种食管鳞癌细胞系中TUSC7的表达，进一步通过体外过表达或抑制TUSC7，进行MTT，划痕实验和细胞侵袭实验分析TUSC7对细胞迁移及侵袭的影响。Western blot检测过表达或抑制TUSC7对食管鳞癌细胞上皮间质转化（EMT）的标志物（MMP-9、E-cadherin、N-cadherin和Vimentin）蛋白表达的影响。
结果: 食管鳞癌患者血清中LncRNA TUSC7的表达低于正常健康对照组（P < 0.05）；TUSC低表达与肿瘤分期、淋巴结转移及组织浸润程度相关（P < 0.05）。细胞水平上实验组TUSC7表达水平低于对照组（P < 0.05）；过表达TUSC7可显著抑制食管癌细胞的迁移和侵袭能力（P < 0.05）；并提高KYSE-30 细胞EMT 相关蛋白E-cadherin，而降低MMP-9、N-cadherin 和Vimentin 蛋白表达量（P < 0.05）；而抑制TUSC7后结果相反。
结论: TUSC7在ESCC血清和细胞系中表达下调，与食管鳞癌淋巴结转移相关，且具有通过EMT促进肿瘤细胞迁移和侵袭的功能。因此血清中TUSC7具有成为食管鳞癌诊疗和转移监测的分子标记物的可能。
Keywords: TUSC7; epithelial-mesenchymal transition; esophageal squamous cell carcinoma; long non-coding RNA; metastasis.