Astaxanthin Inhibits Proliferation of Human Gastric Cancer Cell Lines by Interrupting Cell Cycle Progression

BACKGROUND/AIMS: Astaxanthin is a carotenoid pigment that has antioxidant, antitumoral, and anti-inflammatory properties. In this in vitro study, we investigated the mechanism of anticancer effects of astaxanthin in gastric carcinoma cell lines. METHODS: The human gastric adenocarcinoma cell lines AGS, KATO-III, MKN-45, and SNU-1 were treated with various concentrations of astaxanthin. A cell viability test, cell cycle analysis, and immunoblotting were performed. RESULTS: The viability of each cancer cell line was suppressed by astaxanthin in a dose-dependent manner with significantly decreased proliferation in KATO-III and SNU-1 cells. Astaxanthin increased the number of cells in the G0/G1 phase but reduced the proportion of S phase KATO-III and SNU-1 cells. Phosphorylated extracellular signal-regulated kinase (ERK) was decreased in an inverse dose-dependent correlation with astaxanthin concentration, and the expression of p27(kip-1) increased the KATO-III and SNU-1 cell lines in an astaxanthin dose-dependent manner. CONCLUSIONS: Astaxanthin inhibits proliferation by interrupting cell cycle progression in KATO-III and SNU-1 gastric cancer cells. This may be caused by the inhibition of the phosphorylation of ERK and the enhanced expression of p27(kip-1).

The Inhibitory Effect of Amiloride on the Growth of Human Gastric Carcinoma Cells in Vitro / 대한암학회지

PURPOSE: In the present study the effects of amiloride on the growth of human gastric adenocarcinoma cell line, AGS cells were examined with or without the addition of 5-fluorouracil (5-FU) in vitro. MATERIALS AND METHODS: The growth of AGS cells was examined by counting number of cells on two and four days post-treatment with 50 micrometer, 100 micrometer, 200 micrometer, 400 micrometer, 800 micrometer, amiloride, and 0.1 microgram/ml, 0.3 microgram/ml 5-FU, after plating AGS cells into 6 well plates at a density of 10 x 10(4) cells/well. The reversibility of the effects of amiloride was examined on two to eight days post-treatment with 400 micrometer amiloride after seeding 2 x 10(4) cells/dish. Cell cycle analysis was performed after four day-treatment with 400 micrometer amiloride. RESULTS: Amiloride (50~800 micrometer) significantly inhibited the growth of AGS in a dose-dependent fashion (p<0.05). The inhibitory effect of amiloride on growth of AGS was reversible since removal of amiloride after 24 hours treatment led to resumption of rapid growth up to control levels. Amiloride combined with 5-FU markedly inhibited the growth of AGS in a dose-dependent fashion compared to that of amiloride or 5-FU alone (p<0.05). The fraction of S phase, G0-G1 phase and G2-M phase was 19.3%, 55.7%, 18.8%, in the amioride group (400 micrometer) and 43.9%, 37.4%, 25.1% in the control group, respectively, showing significantly higher G1 fraction in amiloride group compared to control. CONCLUSION: This is the first paper which reported that amiloride inhibited in vitro growth of human gastric adenocarcinoma cells and that its effect of growth inhibition may be synergistic with 5-FU. Amiloride given with or without 5-FU may be useful agent in the treatment of gastric carcinomas. The inhibitory effects of amiloride on the growth of AGS may be mediated in part by blocking G1-S transition of cell cycle.

Expression of Matrix Metalloproteinase-1,2,3 and Type IV Collagen in Gastric Adenocarcinoma: Influence on Lymph Node Metastasis and Prognosis

Matrix metalloproteinases are believed to play an important role in tumor invasion and metastasis. But little is known about the role of them in the gastric adenocarcinoma. We investigated the expression of matrix metalloproteinase-1,2,3 in eighty paraffin blocks of the primary gastric adenocarcinoma tissues with immunohistochemistry and analysed their correlation with lymph node metastasis and survival. MMP-1,2,3 were expressed most intensely in the fibroblasts around the tumor stroma. In our study the increased immunoreactivity of MMP-2 only showed statistically significant correlation with lymph node metastasis (P=0.0517, Odd's ratio=2.274). But MMP-1,2,3 all were correlated with survival. Type IV collagen was observed in the vascular basement membranes and tumor basement membranes and showed statistically significant correlation with lymph node metastasis (P=0.0002, Odd's ratio=0.194) and prognosis (P=0.0001). The immunoreactivity of MMP-2 and type IV collagen was inversely correlated (Kendall's Tau-b correlation = 0.37482, P=0.0001). Our results suggest that in human gastric adenocarcinoma the increased immunoreactivity of MMP-2 and the decreased immunoreactivity of type IV collagen has an important role in lymph node metastasis and prognosis. MMP-1,3 are not correlated with lymph node metastasis but correlated with survival. The mechanism responsible for the production of MMP by the host fibroblasts remains obscure and requires further investigation.