Down-regulation of gut-enriched Kruppel-like factor expression in esophageal cancer

Abstract

Aim: Esophageal carcinoma is one of the most common malignant tumors in China. But the molecular mechanisms of esophageal carcinoma remains unclear. Gut-enriched Kruppel-like factor (GKLF) is a newly identified transcription factor which is expressed abandantly in the epithelial cells of the gastrointestinal tract and deregulation of GKLF was linked to several types of cancer. It is of interest to study the expression and role of GKLF in esophageal carcinoma.

Methods: Semi-quantitative RT-PCR was used to compare GKLF expression in esophageal squamous cell carcinoma to normal mucosa of the same patients. The serum deprivation inducibility of GKLF was observed in an esophageal squamous cancer cell line by comparison to the primary culture of human fibroblast. The effect of antisense GKLF transfection on the proliferation and adhesion of esophageal squamous cancer cell line was also observed.

Results: The level of GKLF transcript is lower in esophageal squamous cell carcinoma compared to paired normal-appearing mucosa in 14 of 17 of the tumors analyzed. The serum deprivation inducibility of GKLF was greatly decreased in an esophageal squamous cancer cell line compared to the primary culture of human fibroblast. Decreased expression of GKLF in the esophageal cancer cell by antisense GKLF transfection increased its proliferation rate compared with that of vector transfected cell control (P<0.05). Transfection of antisense GKLF decreased its adhesion ability (P<0.05).

Conclusion: The findings of this study demonstrate the down-regulation of GKLF in esophageal squamous cancer, and suggest that deregulation of GKLF may play a role in initiation and/or progression as well as the metastasis of esophageal squamous cancer.

Figure 1

Semi-quantitative RT-PCR of GKLF in esophageal squamous cancer patients. RNA from specimens of normal appearing mucosa (N) and cancer (C) were extracted and GKLF as well as GAPDH were amplified. This figure showed the rep-resentative results from several individual patients.

Figure 2

Serum deprivation induced GKLF expression. Both human primary cultured fibroblast and an esophageal squa-mous cancer cell line EC9706 was underwent serum deprivation. GKLF expression was measured semi-quantitively by RT-PCR. The magnitude of GKLF expression was calcu-lated as ratio of GKLF to GAPDH.

Figure 3

Cell growth and adhesion in GKLF transfected EC9706 cells. The cells were transiently transfected with antisense GKLF expression plasmid (AS) and pCDNA3.1 as control (C). The GKLF expression levels detected by RT-PCR were shown in the upper panel. The cell growth rates were shown in the middle panel; each data point represents mean ± S.E.M. of 7 repeats; there was a significant difference between AS and C (P < 0.05). The cell adhesions were shown in the lower panel; each data point represents mean ± S.E.M. of 4 repeats; AS had significant difference compared to C (P < 0.05).