Effects of melatonin on HIF-1α and VEGF expression and on the invasive properties of hepatocarcinoma cells - PubMed (original) (raw)

Effects of melatonin on HIF-1α and VEGF expression and on the invasive properties of hepatocarcinoma cells

Jucimara Colombo et al. Oncol Lett. 2016 Jul.

Abstract

Liver cancer is the sixth most commonly occurring cancer globally, and the main histological type is hepatocellular carcinoma. This type of neoplasia has a poor prognosis due to a high rate of recurrence and intrahepatic metastasis, which are closely are closely associated with the angiogenic process. Vascular endothelial growth factor (VEGF), which is under the control of hypoxia inducible factor-1α (HIF-1α), stimulates the proliferation of endothelial cells and increases cell permeability, promoting the growth, spread and metastasis of tumors. Melatonin, the main hormone secreted by the pineal gland, may have a significant role in tumor suppression and has demonstrated antiangiogenic and antimetastatic effects. The aim of the present study was to analyze the cell viability, migration and invasion, as well as the expression of proangiogenic proteins VEGF and HIF-1α, in HepG2 hepatocarcinoma cells, following treatment with melatonin. Cells were cultured and cell viability was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of proangiogenic proteins VEGF and HIF-1α, under conditions of normoxia and hypoxia, was verified using immunocytochemistry and quantified by densitometry. The analysis of the processes of cell migration and invasion was performed in a Boyden chamber. The MTT assay revealed a reduction in cell viability (P=0.018) following treatment with 1 mM melatonin for 24 h. The expression of proangiogenic proteins VEGF and HIF-1α was reduced in cells treated with 1 mM melatonin for 24 h in normoxic (P<0.001) and hypoxic (P<0.001) conditions, compared with the control group and with induced hypoxia alone. The rate of cell migration and invasion was additionally reduced in cells treated with 1 mM melatonin for 48 h when compared with the control group (P=0.496). The results of the present study suggest that melatonin may have an antiproliferative, antiangiogenic and antimetastatic role in hepatocarcinoma cells and may present a novel therapeutic option for the treatment of liver cancer.

Keywords: HepG2; hypoxia-inducible factor 1α; invasion assay; liver cancer; melatonin; vascular endothelial growth factor.

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Figures

Figure 1.

Figure 1.

Analysis of cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay in liver cancer cells following 24 h of treatment with melatonin (1 nM, 100 nM, 10 µM and 1 mM). Data are expressed as a percentage of the control group, and presented as the mean ± standard deviation. *P<0.05 compared with the control.

Figure 2.

Figure 2.

Immunocytochemistry of the protein HIF-1α, showing HepG2 cells (magnification, ×40) following 24 h of treatment with CoCl2 (100 µM) for induction of hypoxia and/or melatonin (1 mM). (A) Untreated cells (control group). (B) Cells with induced hypoxia. (C) Cells with induced hypoxia treated with melatonin. (D) Cells treated with melatonin alone. (E) Statistical analysis of protein expression of HIF-1α in the experimental groups. Data are presented as the mean optical density ± standard error, and are shown in arbitrary units. *P<0.05 compared with the control group. #P<0.05 compared with cells treated with CoCl2 alone. H + M, hypoxia and melatonin, M, melatonin; HIF-1α, hypoxia-inducible factor 1 α.

Figure 3.

Figure 3.

Immunocytochemistry of the protein VEGF, showing HepG2 cells (magnification, ×40) following 24 h of treatment with CoCl2 (100 µM) for induction of hypoxia and/or melatonin (1 mM). (A) Untreated cells (control group). (B) Cells with induced hypoxia. (C) Cells with induced hypoxia treated with melatonin. (D) Cells treated with melatonin alone. (E) Statistical analysis of protein expression of VEGF in the experimental groups. Data are presented as the mean optical density ± standard error, and are shown in arbitrary units. *P<0.05 compared with the control group. #P<0.05 compared with cells treated with CoCl2 alone. H+M, hypoxia and melatonin; M, melatonin; VEGF, vascular endothelial growth factor.

Figure 4.

Figure 4.

Migration and invasion rate of the HepG2 cell line following 48 h of treatment with 1 mM melatonin. (A) Comparison between positive and negative control. (B) Comparison between the control with 10% fetal bovine serum without treatment and cells treated with 1 mM melatonin. Data are presented as the mean ± standard deviation. *P<0.05.

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References

    1. Jemal A, Center MM, DeSantis C, Ward EM. Global patterns of cancer incidence and mortality rates and trends. Cancer Epidemiol Biomarkers Prev. 2010;19:1893–1907. doi: 10.1158/1055-9965.EPI-10-0437. - DOI - PubMed
    1. Yuan GJ, Li QW, Shun SL, Wang WM, Jiang S, Xu XM. Hyperthermia inhibits hypoxia-induced epithelial-mesenchymal transition in HepG2 hepatocellular carcinoma cells. World J Gastroenterol. 2012;18:4781–4786. doi: 10.3748/wjg.v18.i34.4781. - DOI - PMC - PubMed
    1. Sun XT, Yuan XW, Zhu HT, Deng ZM, Yu DC, Zhou X, Ding YT. Endothelial precursor cells promote angiogenesis in hepatocellular carcinoma. World J Gastroenterol. 2012;18:4925–4933. doi: 10.3748/wjg.v18.i35.4925. - DOI - PMC - PubMed
    1. Karamysheva AF. Mechanisms of angiogenesis. Biochemistry (Mosc) 2008;73:751–762. doi: 10.1134/S0006297908070031. - DOI - PubMed
    1. Lv D, Cui PL, Yao SW, Xu YQ, Yang ZX. Melatonin inhibits the expression of vascular endothelial growth factor in pancreatic cancer cells. Chin J Cancer Res. 2012;24:310–316. doi: 10.1007/s11670-012-0269-6. - DOI - PMC - PubMed

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