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Antimicrobial peptide LL-37 promotes the proliferation and invasion of skin squamous cell carcinoma by upregulating DNA-binding protein A

View Article: PubMed Central - PubMed

ABSTRACT

The antimicrobial peptide LL-37 not only contributes to the host defence against microbial invasion but also regulates immune activity, angiogenesis and cell proliferation. Studies have shown that LL-37 participates in the development of a variety of tumours, such as lung cancer, ovarian cancer, breast cancer and melanoma. However, the role of LL-37 in the development of skin squamous cell carcinoma (SCC) is not clear. The present study used immunohistochemistry to confirm that the expression of human DNA-binding protein A (dbpA) was increased in SCC tissues. After stimulating SCC A341 cells, LL-37 was shown promote the proliferation, migration and invasion of these malignant cells. LL-37 also promoted the upregulation of dbpA mRNA and protein expression. In addition, after using small interfering RNA to silence the normal dbpA expression in these malignant cells, the proliferation and invasion of the tumor cells were significantly reduced. When the NF-κB inhibitor PDTC was used to inhibit the process of LL-37-stimulated cells, it was found that the original upregulated expression of dbpA was downregulated. Overall, the present demonstrated that by upregulating the expression of dbpA, LL-37 can promote the proliferation and invasion of tumour cells, and that this process depends on the NF-κB signalling pathway.

No MeSH data available.


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(A) Expression of dbpA in A431 cells after treatment with dbpA siRNA. Western blot analysis of dbpA and β-actin expression in the dbpA siRNA(1–3) and control siRNA groups. (B) DbpA siRNA reduced the proliferation ability in the A431 cells. After treatment with dbpA siRNA for 24 h, an MTT assay was performed to analyse cell proliferation by reading absorbance at 490 nm in each well using an automatic microplate reader and (C) the invasion ability of the cells was also assessed (magnification, ×200). (D) The proliferation of the A431 cells was promoted by culturing with 0.05, 0.5, 5 or 20 µg/ml LL-37 for 24, 48 or 72 h. Cell proliferation levels were also analysed by MTT assay. The results from three independent experiments are shown as the mean ± standard deviation. n=5 samples in each group. *P<0.05 vs. control. siRNA, small interfering RNA; dbpA, DNA-binding protein A; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.
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f2-ol-0-0-4865: (A) Expression of dbpA in A431 cells after treatment with dbpA siRNA. Western blot analysis of dbpA and β-actin expression in the dbpA siRNA(1–3) and control siRNA groups. (B) DbpA siRNA reduced the proliferation ability in the A431 cells. After treatment with dbpA siRNA for 24 h, an MTT assay was performed to analyse cell proliferation by reading absorbance at 490 nm in each well using an automatic microplate reader and (C) the invasion ability of the cells was also assessed (magnification, ×200). (D) The proliferation of the A431 cells was promoted by culturing with 0.05, 0.5, 5 or 20 µg/ml LL-37 for 24, 48 or 72 h. Cell proliferation levels were also analysed by MTT assay. The results from three independent experiments are shown as the mean ± standard deviation. n=5 samples in each group. *P<0.05 vs. control. siRNA, small interfering RNA; dbpA, DNA-binding protein A; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.

Mentions: After 48 h of culture, total protein was extracted from the transfected cells and analysed using western blotting. Compared with the control group, the protein expression of dbpA in the dbpA siRNA 2 group was significantly reduced (P=0.008; Fig. 2A); thus, dbpA siRNA 2 was chosen for the subsequent experiments. Compared with the control group, cell proliferation in the presence of the siRNA decreased after 24 h, indicating that the dbpA expression was correlated with the proliferation of the tumour cells (P=0.028; Fig. 2B). Transwell chambers coated with Matrigel were used to study the invasion ability of the A431 cells after inhibiting the dbpA expression. Compared with the control group, the number of invading cells that crossed the membranes diminished after 24 h, indicating that dbpA was correlated with the invasiveness of the tumour cells (P<0.034; Fig. 2C). Thus, the inhibition of dbpA may reduce the proliferation and invasiveness of A431 cells.


Antimicrobial peptide LL-37 promotes the proliferation and invasion of skin squamous cell carcinoma by upregulating DNA-binding protein A
(A) Expression of dbpA in A431 cells after treatment with dbpA siRNA. Western blot analysis of dbpA and β-actin expression in the dbpA siRNA(1–3) and control siRNA groups. (B) DbpA siRNA reduced the proliferation ability in the A431 cells. After treatment with dbpA siRNA for 24 h, an MTT assay was performed to analyse cell proliferation by reading absorbance at 490 nm in each well using an automatic microplate reader and (C) the invasion ability of the cells was also assessed (magnification, ×200). (D) The proliferation of the A431 cells was promoted by culturing with 0.05, 0.5, 5 or 20 µg/ml LL-37 for 24, 48 or 72 h. Cell proliferation levels were also analysed by MTT assay. The results from three independent experiments are shown as the mean ± standard deviation. n=5 samples in each group. *P<0.05 vs. control. siRNA, small interfering RNA; dbpA, DNA-binding protein A; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4998069&req=5

f2-ol-0-0-4865: (A) Expression of dbpA in A431 cells after treatment with dbpA siRNA. Western blot analysis of dbpA and β-actin expression in the dbpA siRNA(1–3) and control siRNA groups. (B) DbpA siRNA reduced the proliferation ability in the A431 cells. After treatment with dbpA siRNA for 24 h, an MTT assay was performed to analyse cell proliferation by reading absorbance at 490 nm in each well using an automatic microplate reader and (C) the invasion ability of the cells was also assessed (magnification, ×200). (D) The proliferation of the A431 cells was promoted by culturing with 0.05, 0.5, 5 or 20 µg/ml LL-37 for 24, 48 or 72 h. Cell proliferation levels were also analysed by MTT assay. The results from three independent experiments are shown as the mean ± standard deviation. n=5 samples in each group. *P<0.05 vs. control. siRNA, small interfering RNA; dbpA, DNA-binding protein A; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.
Mentions: After 48 h of culture, total protein was extracted from the transfected cells and analysed using western blotting. Compared with the control group, the protein expression of dbpA in the dbpA siRNA 2 group was significantly reduced (P=0.008; Fig. 2A); thus, dbpA siRNA 2 was chosen for the subsequent experiments. Compared with the control group, cell proliferation in the presence of the siRNA decreased after 24 h, indicating that the dbpA expression was correlated with the proliferation of the tumour cells (P=0.028; Fig. 2B). Transwell chambers coated with Matrigel were used to study the invasion ability of the A431 cells after inhibiting the dbpA expression. Compared with the control group, the number of invading cells that crossed the membranes diminished after 24 h, indicating that dbpA was correlated with the invasiveness of the tumour cells (P<0.034; Fig. 2C). Thus, the inhibition of dbpA may reduce the proliferation and invasiveness of A431 cells.

View Article: PubMed Central - PubMed

ABSTRACT

The antimicrobial peptide LL-37 not only contributes to the host defence against microbial invasion but also regulates immune activity, angiogenesis and cell proliferation. Studies have shown that LL-37 participates in the development of a variety of tumours, such as lung cancer, ovarian cancer, breast cancer and melanoma. However, the role of LL-37 in the development of skin squamous cell carcinoma (SCC) is not clear. The present study used immunohistochemistry to confirm that the expression of human DNA-binding protein A (dbpA) was increased in SCC tissues. After stimulating SCC A341 cells, LL-37 was shown promote the proliferation, migration and invasion of these malignant cells. LL-37 also promoted the upregulation of dbpA mRNA and protein expression. In addition, after using small interfering RNA to silence the normal dbpA expression in these malignant cells, the proliferation and invasion of the tumor cells were significantly reduced. When the NF-&kappa;B inhibitor PDTC was used to inhibit the process of LL-37-stimulated cells, it was found that the original upregulated expression of dbpA was downregulated. Overall, the present demonstrated that by upregulating the expression of dbpA, LL-37 can promote the proliferation and invasion of tumour cells, and that this process depends on the NF-&kappa;B signalling pathway.

No MeSH data available.


Related in: MedlinePlus