| Summary: | 碩士 === 弘光科技大學 === 營養醫學研究所 === 107 === The expression of Matrix metalloproteinases (MMPs) has close relationship with the invasion and metastasis of tumor. Stadies have verified that the expression and activity of MMPs in tumor cells is adjusted by the Arylhydrocarbon receptor (AhR) route. The Benzo[a]pyrene is a ligand of AhR. In vivo and vitro studies have found that the BaP promotes the metastasis tumor cells by activating AhR relevant molecule route. The peel of citrus fruits contains abundant phytochemicals, many which have the function of anti-oxidization, anti-cancer and anti-metastasis of cancer etc. The lime peel contains abundant terpene and flavonoid; among them, nomilin (NMN) is most common terpene. Studies have found that NMN has the potential to inhibit the metastasis of cancer, but it was still unclear about it influence and mechanism of lung cancer cell metastasis in BaP-induced AhR excessive expression.
Firstly, this research used NCI-H1355 with higher AhR expression and A549 cell with lower AhR expression for human lung cancer cells induced from BaP as the metastasis mode. Comparing the influence of NMN and lime peel ethanol extract (LPE) on the metastasis of NCI-H1355 and A549 for human lung cancer cells induced from BaP. After the human lung cancer cells were cultivated together with 30-100 μM NMN and 50, 100 μg/mL LPE for 24 hours, the result revealed that the NMN and LPE inhibited the invasion of NCI-H1355 cells and A549 cells (p<0.05). As for NCI-H1355 cells, under 100 μM NMN and 100 μg/mL LPE, the inhibition of invasion was 33% and 37%, respectively, and for A549 cells, the inhibition was 10% and 22%, respectively. Under the same dosage, the inhibition of invasion by NMN and LPE was better for NCI-H1355 cells than for A549 cells (330% vs. 168% , p<0.05). It was predicted that the inhibition of invasion by NMN and LPE was better for the cells with higher AhR expression. So, we would use the NCI-H1355 cells as the mode to study the possible mechanism for NMN and LPE to inhibit BaP-induced invasion.
The research pointed out that using BaP combined with AhR to enter the cells, it would activated the cytochrome P450 1A1 (CYP1A1) enzyme for metabolism. In the metabolism process, a large amount of reactive oxygen species (ROS) and cytokines was produced to stimulate MMPs expression and then promote the metastasis of lung cancer. The result revealed that NMN and LPE significantly inhibited the protein expression of AhR and CYP1A1 (p<0.05). The inhibition rate of 100 μM NMN was 42% and 65%, respectively. The inhibition rate of 100 μg/mL LPE was 59% and 77% (p<0.05), respectively. In addition, the result also revealed that that NMN and LPE significantly inhibited the production of ROS and IL-6 (p<0.05). Among them, as for the inhibition rate of IL-6, NMN (100 μM) and LPE (100 μg/mL) could be up to 38% and 47%, respectively. We further found that NMN and LPE could inhibit the expression of MMP-2 and MMP-9 albumen. The inhibition rate of 100 μM NMN and 100 μg/mL LPE on MMP-2 was 78% and 83% (p<0.05), respectively. The inhibition rate of 100 μM NMN and 100 μg/mL LPE on MMP-9 was 66% and 64% (p<0.05), respectively.
In summary, the NMN and LPE inhibits the invasion induced from BaP. It was predicted that the possible mechanism might be through inhibiting AhR albumen, to inhibit the production of ROS and IL-6 from the downstream CYP1A1 metabolism of BaP, and then further inhibit the expression of MMP-2 and 9.
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