| Lung cancer is the highest mortality cancers. Many factors can lead to lung cancer occurrence and deteriorating. Nicotine (Nict) in tobacco plays an important role in the spread of lung cancer. Two Importantl monomer components in tea --- Epigallocatechin gallate (EGCG) and Theanine play adjusting roles in many aspects for cancer. It has not been reported that whether these two functional components using together inhibit the negative effects on lung by nicotine.The optimal concentrations of EGCG, Theanine, Nicotine treat H1299 lung adenocarcinoma cells were measured by MTT; The EGCG, Theanine and Nicotine for the mRNA and protein relative expression level of Bax, Bcl-2, Jak2 and Stat3 in H1299 cells were measured by qRT-PCR and Western blot. Eight kinds of antioxidants(tea polyphenols, resveratrol, vitamin C, rutin, quercetin, chlorogenicacid, anthocyanins and proanthocyanidins)were added to cigarette filters and collected the smokes, Then explore filterable smoke’s effect on the protein expression of Bcl-2, Bax, and STAT3 in HEK 293 by MTT and Western blot..The experimental results show that:(1) the half inhibitory concentration(IC50 value) of EGCG for H1299 cells is about 32 nmol-L-1(24 h);the half inhibitory concentration (IC50 value) of Theanine concentration for HI299 cells is about 250 mmol·L-1 (24 h); Combing Theanine and EGCG to treat H1299 cells,Their combination index> 1;Nicotine (1 μmol-L-1) has promotion proliferation effect on H1299 cells. (2)EGCG (15μmol·L-1) and Theanine (100 mmol·L-1) pretreatment H1299 cells for 24 h respectively can significantly decrease. Nicotine (1μmol·L-1) promoting proliferation effect on H1299 cells. (3) Nicotine (1 μmol·L-1) treat H1299 cells could reduce the relative mRNA expression of Bax, down-regulate the mRNA relative expression levels of Bcl-2, Jak2, Stat3; Comparing with the Nicotine treatment group,EGCG (15μmol·L-1), Theanine (100 mmol·L-1) pretreatment groups can reverse regulate Nicotine induced the mRNA gene expression of Jak2, Stat3 in JAK2/STAT3 signaling pathway. But Theanine has no significant impacts on the expression mRNA levels of Bax, Bcl-2 gene, EGCG has a significant difference for the expression mRNA levels of Bax, Bcl-2 gene(P<0.05). (4) Comparing with the control group, EGCG has negative effects on the protein expressions for Jak2 and Stat3, EGCG can improve the ratio of Bax and Bcl-2 in lung cancer H1299 cells, but Nict decrease the ratio of Bax and Bcl-2 in the H1299 cells. Comparing with the model group (Nict group), pretreated with EGCG then using Nict treat H1299 cells, the mRNA relative expression levels of Jak2, Stat3 and the ratio of Bax and Bcl-2 in H1299 cells were decreased. (5) Cigarette smoke could reduce the survival rates of HEK293 cell and appeared a dose-dependent manner, up-regulated Bcl-2 protein relative expression, down-regulated the relative expression levels of Bax, and STAT3 proteins, each protein expression levels were appeared in dose-dependent effects for HEK293 cells. Comparing to the control, adding 8 kinds of antioxidants to cigarette filters could obviously inhibit the death rates of HEK293 cells caused by cigarette smoke. The results had significant differences (P<0.05), and tea polyphenols was the best.So, it could be concluded that:EGCG, Theanine can inhibit proliferation of H1299 cell induced by Nicotine, and Bax, Bcl-2, Jak2 and Stat3 gene may be involved in these expression process.8 kinds of antioxidants(Tea polyphenols, resveratrol, vitamin C, rutin, quercetin, chlorogenicacid, anthocyanins and proanthocyanidins) could protect HEK293 cell from damage caused by cigarettes smoke. Tea polyphenols has the best potential protective ability. |
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