Contribution of TWIST1-EVX1 Axis in Invasiveness of Esophageal Squamous Cell Carcinoma; a Functional Study.

Background: Epithelial-mesenchymal transition (EMT) is a biological process in embryonic development and cancer progression, and different gene families, such as HOX genes, are closely related to this process.

Objectives: Our aim in this study was to investigate the correlation between TWIST1 and EVX1 mRNA expression in ESCC patients and also examine the probable regulatory function of TWIST1 on EVX1 expression in human ESCC cell line.

Materials and methods: TWIST1 and EVX1 gene expression patterns were assessed in ESCC patients by relative comparative Real-time PCR then correlated with their clinical characteristics. In silico analysis of the EVX1 gene was conducted. KYSE-30 cells were transduced by a retroviral system to ectopically express TWIST1, followed by qRT-PCR to reveal the correlation between TWIST1 and EVX1 gene expression.

Results: The expression of TWIST1 and EVX1 was correlated to each other significantly (p=0.005) in ESCC. Of 28 patients with under/normal expression of TWIST1, 22 samples (78.57%) had over/normal expression of EVX1. TWIST1 overexpression was correlated with advanced stages of the tumor (III, IV) (P = 0.019) and lymph node metastasis. However, EVX1 under expression was associated with lymph node metastasis (p = 0.027) and invasiveness of the disease (P = 0.037) in ESCC. Furthermore, retroviral transduction enforced significant overexpression of TWIST1 in GFP-hTWIST-1 approximately 9-fold compared to GFP control cells, causing a - 8.83- fold reduction in EVX1 mRNA expression significantly.

Conclusions: Our results indicated the repressive role of TWIST1 on EVX1 gene expression in ESCC. Therefore, our findings can help dissect the molecular mechanism of ESCC tumorigenesis and discover novel therapeutic targets for ESCC invasion and metastasis.