Expression of engrailed homeobox 2 regulates the proliferation, migration and invasion of non‑small cell lung cancer cells

Abstract

The present study aimed to investigate the expression, biological function and mechanism of action of engrailed homeobox 2 (EN2) in non-small cell lung cancer (NSCLC) at the tissue and cellular level. A total of 42 patients who underwent surgical resection of NSCLC tissues between January 2014 and January 2015 were included in the present study. EN2 mRNA expression levels in explanted NSCLC tissues were determined using reverse-transcription quantitative polymerase chain reaction analysis. Adenocarcinoma human alveolar basal epithelial A549 cells were transfected with negative control plasmids or those containing EN2, enabling its overexpression. To assess the effect of EN2 overexpression in A549 cells, a Cell Counting kit-8 assay was used to analyze cellular proliferation, a Transwell assay was used to evaluate cellular migration and invasion and flow cytometry was used to detect the cell cycle distribution. To measure protein expression of EN2 and β-catenin in A549 cells, western blotting was also conducted. EN2 mRNA expression levels in NSCLC tissues were lower than those in normal tissues, and were associated with metastasis, clinical staging and differentiation degrees of NSCLC. Increased expression of EN2 inhibited the proliferation of A549 cells , and suppressed their migration and invasion. Elevated EN2 expression inhibited the proliferation of A549 cells by regulating the G/S phase transition. β-catenin protein expression levels and nuclear translocation in A549 cells were inhibited by EN2 overexpression. The present study demonstrated that expression of EN2 in NSCLC tissues was downregulated and negatively associated with the degree of disease differentiation, lymphatic metastasis and clinical staging. Overexpression of EN2 inhibits the proliferation, migration and invasion of A549 cells, as well as the expression of β-Catenin and nuclear translocation.

EN2 as an oncogene promotes tumor progression via regulating CCL20 in colorectal cancer

“…Recent studies have shown that homeobox-containing genes, including HOX, EMX, PAX, EN, and so on, as key regulators contribute to the development and progression of a variety of human cancers 3 , 18 , 19 . As the human engrailed homolog, EN2 has been reported to correlate closely with human cancers such as prostate, breast, bladder, ovarian cancer, and non -small cell lung cancer 6 – 8 , 20 , 21 . However, it remains unclear whether EN2 has any role in colorectal cancer.…”

Engrailed 2 (EN2) acts as a glioma suppressor by inhibiting tumor proliferation/invasion and enhancing sensitivity to temozolomide

“…EN2 is a member of the homeobox family, which encodes a homeodomain-containing transcription factor that is essential for early development. Elevation of EN2 has been highly correlated with the proliferation, invasion, and migration in several types of malignancies [18][19][20][21][22][23][24][25][26], however, controversial results show that EN2 is silenced in other cancers [27][28][29], and thus EN2 acts as a potential diagnostic and prognostic biomarker [23,[30][31][32][33]. However, decreased EN2 in renal carcinoma has been observed and downregulation of EN2 in 786-O cell line promoted proliferation and reduced apoptosis [27,34,35].…”

“…Engrailed-2 (EN2) gene encodes a homeobox-containing transcription factor and participates in the regionalization, patterning and cell differentiation in early brain development [15][16][17]. Accumulated evidence demonstrates that EN2 is highly associated with tumorigenesis in some types of cancers [18][19][20][21][22][23][24][25][26], however, controversial results show that EN2 is silenced in other cancers [27,28]. As for glioma, it remains unclear about EN2 expression pattern and potential functions.…”

The voltage-gated sodium channel Nav1.7 associated with endometrial cancer

“…After 6-48 hour, non-invading cells were scraped from the upper side of the insert using a cotton swab. Invading cells on the bottom of the insert were fixed and stained with Diff-Quick Stain (IMEB Inc., USA) according to manufacturer's instructions 20-22. The total number of invading cells was counted for each insert under a light microscope (Nikon Corporation, Japan).…”