The expression and correlation between chemokine CCL7 and ABCE1 in non-small cell lung cancer

Abstract

Lung cancer is a malignant disease, and has the highest incidence and mortality worldwide. Lung cancer is also a popular subject in the field of cancer research. The molecular mechanisms of lung cancer development, invasion and metastasis need to be determined to prolong survival times and improve the quality of life. Recent studies have demonstrated that ATP-binding cassette sub-family E member 1 (ABCE1) is one of the factors that contributes to the development and metastasis of lung cancer, but the specific mechanism of this phenomenon remains unclear. A polymerase chain reaction microarray was used in the present study to screen for chemokine (C-C motif) ligand 7 (CCL7) expression in cell lines that highly expressed ABCE1, and the results showed that CCL7 was highly expressed in H1299 cells (P<0.01). The expression of CCL7 and ABCE1 in lung cancer tissues obtained from 30 patients with non-small cell lung cancer (NSCLC) was higher than that in adjacent normal lung tissues (P<0.01), and a positive correlation between the expression levels of the two genes in NSCLC was observed. These findings indicate that ABCE1 is involved in the development and progression of lung cancer through the CCL7 signaling pathway.

Keywords: ABCE1; CCL7; invasion; metastasis; non-small cell lung cancer.

Figure 1.

Fluorescence microscopic observation of H1299 cells 72 h after transfection with the ABCE1-overexpression lentiviral vector or empty vector (×400). The images in the first column are cells under bright field, the images in the second column are cells carrying green fluorescent protein under dark field, and the images in the third column are combined images from the first two columns. These images demonstrate that the transfection efficiency was greater than 80%. The last lane is samples from control cells. ABCE1, ATP-binding cassette transporter E1.

Figure 2.

Volcano plot of gene expression differences, with the difference between the experimental data for the two groups as the x-axis and the P-value as the y-axis. The blue line represents P<0.05, and the arrow indicates CCL7. CCL7, chemokine (C-C motif) ligand 7.

Figure 3.

The western blotting results. (A) CCL7 and ABCE1 protein content in H1299 cells transfected with the ABCE1-overexpressing lentivirus was significantly higher than that in the empty vector control and normal control groups. (B) Histogram showing that the expression of CCL7 and ABCE1 in the ABCE1-upregulation group was higher than that in the empty vector and normal control groups, *P<0.01. ABCE1, ATP-binding cassette sub-family E member 1; CCL7, chemokine (C-C motif) ligand 7.

Figure 4.

(A) Immunohistochemical experiments under an optical microscope (×400): CCL7 and ABCE1 expression was upregulated in lung SCC and AC, as demonstrated by the brown granules in the cytoplasm, and was low in adjacent normal lung tissues. The right side of each group is a negative control. (B) Quantitative immunohistochemical analysis results: The expression of CCL7 and ABCE1 in lung cancer tissues was significantly higher than that in normal lung tissues, *P<0.01. ABCE1, ATP-binding cassette sub-family E member 1; CCL7, chemokine (C-C motif) ligand 7; SCC, squamous cell carcinoma; AC, adenocarcinoma; NT, normal tissue.

Figure 5.

Quantitative PCR experiment. (A) The mRNA expression of CCL7 in lung cancer tissues was significantly higher than that in adjacent NTs, *P<0.01. (B) The mRNA expression of ABCE1 in lung cancer tissues was higher than that in adjacent NTs, *P<0.01. (C) Pearson correlation analysis showed that the expression of CCL7 was positively correlated with that of ABCE1 in lung cancer tissues. ABCE1, ATP-binding cassette sub-family E member 1; CCL7, chemokine (C-C motif) ligand 7; NTs, normal tissues.