Growth arrest and apoptosis of human hepatocellular carcinoma cells induced by hexamethylene bisacetamide.

AIM: To investigate the cellular effects of hybrid polar compound hexamethylene bisacetamide (HMBA) on the growth and apoptosis of human hepatocellular carcinoma cells and to provide the molecular mechanism for potential application of HMBA in the treatment of liver cancer. METHODS: Effects of HMBA on the growth of human hepatocellular carcinoma SMMC-7721 cells were assayed by MTT chronometry. Apoptosis induced by HMBA was detected by phase-contrast microscopy, flow cytometry, propidium iodide staining and immunocytochemical analysis. RESULTS: The growth of SMMC-7721 cells was significantly inhibited by HMBA, and the growth inhibitory rate was 51.1%, 62.6%, 68.7% and 73.9% respectively after treatment with 5.0, 7.5, 10.0 and 12.5 mmol/L of HMBA. In the cells treated with 10 mmol/L of HMBA for 72 h, the population of cells at sub-G(1) phase significantly increased, and the apoptotic bodies and condensed nuclei were detected. Moreover, treatment of SMMC-7721 cells with 10 mmol/L of HMBA down-regulated the expression of Bcl-2 anti-apoptotic protein, while slightly up-regulated the level of pro-apoptotic protein Bax. CONCLUSION: Treatment with 10.0 mmol/L of HMBA can significantly inhibit the growth and induce apoptosis of human hepatocellular carcinoma SMMC-7721 cells by decreasing the ratio of Bcl-2 to Bax.

[Apoptosis of human gastric cancer cell induced by photochemical riboflavin].

BACKGROUND & OBJECTIVE: Photochemical riboflavin, the production of reactive oxygen species (ROS), has been reported having cytotoxity on some cancer cells. The aim of this study was to investigate the effect of photochemical riboflavin on inducing apoptosis in human gastric cancer cell line MGC80-3. METHODS: Trypan blue exclusion method, Giemsa staining, DNA electrophoresis, DNA quantification, Western blot analysis, and flow cytometry were conducted to determine the effect of photochemical riboflavin on cell survival, morphology, DNA fragmentation, gene expression, and cell cycle arresting. RESULTS: The cell viability dropped down according to the riboflavin concentration and treating time. Exposure of the cells in 20 micromol/L riboflavin for 24 hours resulted in typical apoptotic morphology and G(2)/M arresting. As MGC80-3 cells were separately treated with 10, 20, 30, and 40 micromol/L photochemical riboflavin, DNA electrophoresis showed that the ladder bands, a typical feature of apoptotic cell, appeared in the groups treated by over 20 micromol/L photochemical riboflavin. The efficiency rates of DNA fragmentation were 35.4%, 54.1%, 70.6%, and 86.8%, respectively. Western blot analysis showed that the expression of apoptosis related proteins p53, C-myc, and Bax were up-regulated whereas the expression of Bcl-2 was down-regulated. CONCLUSION: These results indicate that photochemical riboflavin has high efficiency of inducing cell apoptosis on MGC 80-3 cells in vitro and there is a correlation between apoptosis and G(2)/M arresting.

Effect of isoverbascoside, a phenylpropanoid glycoside antioxidant, on proliferation and differentiation of human gastric cancer cell.

AIM: To investigate the effects of phenylpropanoid glycoside antioxidant isoverbascoside on cell proliferation and differentiation of human gastric cancer cell line MGC 803. METHODS: MGC 803 cells were treated with isoverbascoside. Its effects on cell proliferation, tumorigenicity, enzymatic activities, cell cycles, and gene expression were respectively evaluated with cell counting, tumor formation assay, enzymatic assay, flow cytometer analysis, and Western blotting, with Me2SO as positive control. RESULTS: Isoverbascoside could markedly inhibit cell proliferation in dose- and time-dependent manner. Isoverbascoside 20 micromol/L strikingly suppressed cell tumorigenicity, activities of alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), and caused G0/G1 arrest. The expression of G1 S checkpoint related proteins, p53, p21/WAF1, and p16/INK4, were up-regulated after MGC 803 cells were treated with isoverbascoside 20 micromol/L for 4-8 h. Contrarily, the expression of C-myc protein was suppressed after 8 h treatment. CONCLUSION: Isoverbascoside inhibited cell proliferation, reversed cell malignant phenotypic characteristics, and consequently caused differentiation in MGC 803 cells. These effects might be associated with its activities of causing G0/G1 arrest and regulating the expression of cell cycle related proteins.

Sequencing of p53 mutation in established human hepatocellular carcinoma cell line of HHC4 and HHC15 in nude mice.

AIM:To set up cell lines of human hepatocellular carcinoma in nude mice for the research of cell biology and gene therapy.METHODS:Xenotransplantation of human hepatoma into nude mice was carried out and the growth rate, histopathology and immunology of the nude mice were studied. The DNA from xenografts were analyzed by HBV gen and PCR amplification of a fragment of p53 gene exon 7, which were identified by dot blot hybridization, restriction fragments length polymorphism and DNA sequencing.RESULTS:HHC4 and HHC15 cell lines could be successively transplanted in nude mice and the population doubling time was 7 and 5 days respectively. These strains retained the original characteristics of histopathology, secreting AFP and heteroploid karyotypes in human hepatocellular carcinoma. The fragment of HBV gene was detected in the genomic DNA of both hHCC4 and hHCC15, however only HHC4 secreted HBsAg.The mutation at 250 code (C A) and 249 code (G T) were detected respectively in the genomic DNA of HHC4 and HHC15.CONCLUSION:The two cell lines are useful material for the studying of cell biology and gene therapy in human hepatocellular carcinoma and provide molecular biological trace of relationship between high mortality of hepatoma and AFB1 severe pollution of the daily common foods in this district.