Gastric Carcinoma Cell Line MGC-803 Research Articles

Cell growth inhibition, G2M cell cycle arrest, and apoptosis induced by the novel compound Alternol in human gastric carcinoma cell line MGC803

Alternol is a novel compound purified from fermentation products of a microorganism in the bark of the yew tree. Because it has a similar origin as the anticancer agent paclitaxel, we hypothesized that Alternol may also have an anti-tumor effect. In this report, we chose human gastric carcinoma cell line MGC803 as the model to investigate the effects of Alternol. We evaluated cell viability using the CCK8 kit. The cell cycle distribution was analyzed by flow cytometry. AnnexinV combined with PI was performed to evaluate the apoptosis rate. The mitochondria membrane potential (MMP) was measured by a fluorescence-activated cell sorter using Rhodamin123 staining. We observed the morphological changes by immunofluorescence and Hochest33342 staining. RT-PCR and Western blot analysis were used to evaluate the changes of G2M-related regulators. Our data show that Alternol inhibited the growth of MGC803 and induced G2M arrest. Coincident with G2M arrest, phosphorylation of CDC2 on Tyr-15 was significantly elevated, which could be explained by the increase of Wee1 and decrease of CDC25C. The decreased expression of PLK1 may cause the elevation of Wee1 and CyclinB1 protein levels. Moreover, the apoptosis seemed to be secondary to G2M arrest because the elevated Caspase3, decreased MMP, and typical apoptotic morphology changes appeared after G2M arrest. These findings suggested that Alternol could inhibit the growth of MGC803 by inducing G2M arrest and apoptosis. We expected Alternol may be used as a lead compound one day and our experiments might provide some clues for further research.

In vitro effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 cells.

To investigate the effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 in vitro and the possible mechanisms involved. Chitosan nanoparticles were characterized by particle size, zeta potential, and morphology. After treatment with various concentrations of chitosan nanoparticles (25, 50, 75, 100 microg/mL) at various time intervals, cell proliferation, ultrastructural changes, DNA fragmentation, mitochondrial membrane potential (MMP), cell cycle phase distribution and apoptotic peaks of MGC803 cells were analyzed by MTT assay, electron microscopy, DNA agarose gel electrophoresis, and flow cytometry. Chitosan nanoparticles exhibited a small particle size as 65 nm and a high surface charge as 52 mV. Chitosan nanoparticles markedly inhibited cell proliferation of MGC803 cells with an IC50 value of 5.3 microg/mL 48 h after treatment. After treatment with chitosan nanoparticles, the typical necrotic cell morphology was observed by electron microscopy, a typical DNA degradation associated with necrosis was determined by DNA agarose electrophoresis. Flow cytometry showed the loss of MMP and occurrence of apoptosis in chitosan nanoparticles-treated cells. Chitosan nanoparticles effectively inhibit the proliferation of human gastric carcinoma cell line MGC803 in vitro through multiple mechanisms, and may be a beneficial agent against human carcinoma.

Induction of apoptosis in human gastric carcinoma cell line MGC-803 by monoclonal antibody PD4

To examine if monoclonal antibody PD4 (McAb PD4) which identifies a surface antigen of 40 kD (P40) expressed in gastric carcinoma cells could induce tumor cell apoptosis. The antibody was tested for its effect on cell cycle and cell injury in gastric carcinoma cell MGC-803 by flow cytometry, DNA electrophoresis and TdT assay. Fas antigen expression in MGC-803 was also examined. McAb PD4 could block tumor cell proliferation cycle and trigger cell death by inducing apoptosis, but expression of Fas antigen in MGC-803 cells was negative. P40 is a tumor associated antigen which is distinct from Fas antigen. Molecular cloning of P40 will clarify the pathway and mechanism of apoptosis induced by this monoclonal antibody.

Involvement of the ALL-1 gene in a solid tumor.

Translocations involving chromosome band 11q23, found in 5-10% of human acute leukemias, disrupt the ALL-1 gene. This gene is fused by reciprocal translocation with a variety of other genes in acute lymphoblastic and myelogenous leukemias, and it undergoes self-fusion in acute myeloid leukemias with normal karyotype or trisomy 11. Here we report an alteration of the ALL-1 gene in a gastric carcinoma cell line (Mgc80-3). Characterization of this rearrangement revealed a three-way complex translocation, involving chromosomes 1 and 11, resulting in a partial duplication of the ALL-1 gene. Sequencing of reverse transcription-PCR products and Northern blot analysis showed that only the partially duplicated ALL-1 gene was transcribed, producing an mRNA with exon 8 fused to exon 2. This report of ALL-1 gene rearrangement in a solid tumor suggests that ALL-1 plays a role in the pathogenesis of some solid malignancies. The absence of the normal transcript in this cell line, in association with the loss-of-heterozygosity studies on chromosome 11q23 seen in solid tumors, suggests that ALL-1 is involved in tumorigenesis by a loss-of-function mechanism.