Résumé
Objective: To study the involvement of MAPK MEK/ERK signaling transduction pathway in the apoptosis process of SW620 tumor cell line and the inhibition effect of resveratrol. Methods: SW620 cell lines were divided into 5 groups, namely, control group, PD98059 group, low-dose resveratrol group, mid-dose resveratrol group and high-dose resveratrol group. The inhibition rate of cell proliferation was detected by MTT method. The expression of apoptotic molecules and MEK/ERK signaling pathway related proteins were assayed by real-time PCR and Western blotting. Results: Compared with control group, the proliferation of cells treated with resveratrol was significantly inhibited. In the case of apoptotic molecules, the expression of Bax, Caspase 3 and Caspase 9 was increased significantly while the expression of anti-apoptotic molecule Bcl2 was decreased significantly in resveratrol groups with a dose-dependent manner. In the case of molecules in MEK/ERK signaling pathway, the expression of Ras, Raf, MEK and ERK1/2 was decreased significantly in resveratrol groups with a dose-dependent manner. Conclusions: PD98059 and resveratrol can effectively inhibit the proliferation of SW620 through inhibiting the MEK/ERK signaling pathway.
Résumé
OBJECTIVE@#To study the involvement of MAPK MEK/ERK signaling transduction pathway in the apoptosis process of SW620 tumor cell line and the inhibition effect of resveratrol.@*METHODS@#SW620 cell lines were divided into 5 groups, namely, control group, PD98059 group, low-dose resveratrol group, mid-dose resveratrol group and high-dose resveratrol group. The inhibition rate of cell proliferation was detected by MTT method. The expression of apoptotic molecules and MEK/ERK signaling pathway related proteins were assayed by real-time PCR and Western blotting.@*RESULTS@#Compared with control group, the proliferation of cells treated with resveratrol was significantly inhibited. In the case of apoptotic molecules, the expression of Bax, Caspase 3 and Caspase 9 was increased significantly while the expression of anti-apoptotic molecule Bcl2 was decreased significantly in resveratrol groups with a dose-dependent manner. In the case of molecules in MEK/ERK signaling pathway, the expression of Ras, Raf, MEK and ERK1/2 was decreased significantly in resveratrol groups with a dose-dependent manner.@*CONCLUSIONS@#PD98059 and resveratrol can effectively inhibit the proliferation of SW620 through inhibiting the MEK/ERK signaling pathway.
Résumé
<p><b>BACKGROUND</b>The high mobility group A1 (HMGA1) proteins are architectural transcription factors found to be overexpressed in lung adenocarcinoma. Lentivirus-mediated RNA interference (RNAi) technology is a powerful tool for silencing endogenous or exogenous genes in human cancer cells. Our preliminary study shows that gemcitabine inhibits growth of the human lung cancer cell line SPCA-1 and induces apoptosis, and this effect might link with down-regulation of HMGA1 expression. This study aimed to investigate the chemosensitivity change of the lung adenocarcinoma cells SPCA-1 after HMGA1 inhibition by lentivirus-mediated RNAi.</p><p><b>METHODS</b>We studied a highly malignant lung adenocarcinoma cell line (SPCA-1 cells). Lentiviral short-hairpin RNA (shHMGA1) expression vectors targeting HMGA1 were used for generation of lentiviral particles. After being transfected into the lung adenocarcinoma cell line SPCA-1, the expression of HMGA1 was determined by retrotranscriptase polymerase chain reaction (RT-PCR) and Western blotting. The effect of gemcitabine on proliferation of positive and negative cells was observed by methyl thiazolyl tetrazolium (MTT) assay and clonogenic survival assay. Apoptosis was observed by flow cytometery. Chemosensitivity to gemcitabine was determined by IC50 analysis. Caspase activity was quantitated by a caspase colorimetric protease assay kit.</p><p><b>RESULTS</b>HMGA1-siRNA silenced its target mRNA specifically and effectively in SPCA-1 cells. The apoptotic rates of the scramble control group were (7.43 ± 0.21)%, (11.00 ± 0.20)%, and (14.93 ± 0.31)%, and the apoptotic rates in the silenced group were (9.53 ± 0.42)%, (16.67 ± 0.45)%, and (25.40 ± 0.79)% under exposure to 0.05, 0.5 and 5.0 µg/ml of gemcitabine (P < 0.05). The IC(50) of the silenced group was (0.309 ± 0.003) µg/ml which was significantly lower than in the scramble control group, (0.653 ± 0.003) µg/ml (P < 0.05). It reduced cancer cell proliferation and increased apoptotic cell death after being treated with gemcitabine compared with the scramble control group. HMGA1 silencing resulted in reduction in the phosphorylation of Akt, and promoted the activation of caspases 3, 8 and 9 upon exposure to gemcitabine.</p><p><b>CONCLUSIONS</b>Lentivirus-mediated RNA interference of HMGA1 enhanced chemosensitivity to gemcitabine in lung adenocarcinoma cells. The mechanism may be associated with the PI-3K/Akt signal pathway. HMGA1 may represent a novel therapeutic target in lung cancer.</p>