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BACKGROUND: Nitrous oxide concentration is easily controlled by respiratory ventilation. It suppresses bone marrow via the inhibition of thymidylate synthesis. The aim of this work was to determine the optimal pressure and exposure duration of nitrous oxide, as well as methotrexate concentration that maximizes the suppression of 4 cancer cells: CCRF-CEM, K562, A549 and MDA-MB-231. METHODS: Each cancer cell was cultured in a hyperbaric chamber at 1, 2 and 3 atmosphere of 74% nitrous oxide for 24, 48, and 72 hours at 0, 0.3, 0.7, 1, 2, 5 and 10 microM methotrexate (MTX), respectively. The results were expressed in the ratio of the number of cancer cells cultured under specific conditions (S cells) to that under normal conditions (N cells). RESULTS: The S/N ratio of CCRF-CEM cells was 87.4% in 24-hour culture, 95.0% in 48-hour culture and 115.9% in 72-hour culture (P 0.05). However, the S/N ratio of MDA-MB 231 cells was 66.9% in 24-hour culture, 83.1% in 48 hour culture and 87.8% in 72-hour culture (P < 0.05). CONCLUSIONS: Only the growth of the MDA-MB-231 cells was significantly reduced after a longer exposure time to nitrous oxide, but those of the other cells were not.
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Atmósfera , Médula Ósea , Células K562 , Metotrexato , Óxido Nitroso , VentilaciónRESUMEN
Objective:To study the inhibitory effect and anti-cancer mechanisms of adenovirus-mediated ING4 gene on the MG-63 osteosarcoma xenografts in nude mice.Methods:Ad-ING4 was transfected into QBI-293 cells and harvested.15 nude mice of the subcutaneous tumor models were established with MG-63 osteosarcoma cells and were randomly divided into PBS,Ad-GFP and Ad-ING4 groups.Then PBS(100 μl),Ad-GFP(100 μl,10~9pfu/ml) and Ad-ING4 (100 μl,10~9pfu/ml) for each one were given respectively QOD for 5 times,with intratumor injections.Tumor volume changes were monitored;and the 15 mice were sacrificed 2 weeks after treatment,the tumors were removed,weighed and ratios of tumor-suppression were calculated.The morphological changes of apoptotic tumor cells were observed under microscope.Bcl-2,Bax,Caspase-3,VEGF,CD34 expression was tested by immumohistochemistry.Results:High titer(10~9pfu/ml)adenoviral vector of ING4 gene were obtained.In nude mice bearing MG-63 osteosarcoma xenografts,the growth of MG-63 tumors treated by intratumoral injecting of Ad-ING4 was significantly suppressed,compared with PBS group and Ad-GFP group.The ratios of tumor weight-suppression of Ad-ING4 group was 59.3%(P＜0.05).Immumohistochemistry displayed that the expression of Bax,Caspase-3 was up-regulated and the expression of Bcl-2,VEGF,CD34 was down-regulated by Ad-ING4.Conclusion:Ad-ING4 can inhibit the growth of MG-63 osteosarcoma xenografts in nude mice,which may be via activating the apoptosis pathway and inhibiting tumor angiogenesis.
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In order to investigate the effect of replication-incompetent adenovirus vector expressing MDA-7/IL-24 on tumor growth and apoptosis of human hepatocellular carcinoma (HCC) cell line SMMC-7721 and normal liver cell line L02, the recombinant replication-incompetent Ad.mda-7 virus vector was constructed and infected into the HCC cell line SMMC-7721 and normal liver cell line L02. RT-PCR was performed to examine the expression of MDA-7 mRNA. The concentrations of MDA-7/IL-4 in culture supernatants were determined by using ELISA. MTT and Hoechst staining assay were applied to observe the inhibitory and killing effects of MDA-7 on the HCC cells. By using flow cytometry, the apoptosis, cell cycle and proliferation of SMMC-7721 and L02 cells were meas- ured. The results showed recombinant replication-incompetent virus expressing MDA-7/IL-24 was constructed successfully, and RT-PCR revealed that it could mediate the high expression of the ex- ogenous gene MDA-7/IL-24 in SMMC-7721 and L02 cells. The expression of MDA-7/IL24 proteins in the culture supernatant was detectable by ELISA. Ad.mda-7 infection induced apoptosis and growth suppression in SMMC-7721 cells and an increased percentage of HCC cells in the G2/M phase of the cell cycle, but not in L02 cells. It was concluded that mda-7/IL-24 gene, mediated with replication-incompetent adenovirus vector, could selectively induce growth suppression and apoptosis in HCC cell line SMMC-7721 but without any toxic side-effect on normal liver line L02.
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Glypican-3 (GPC3) encodes a cell-surface heparan-sulfate proteoglycan and its expression is frequently silenced in ovarian cancer, mesotheliomas, and breast cancer cell lines and ectopic expression of GPC3 inhibited the growth of these cells, suggesting that GPC3 plays a negative role in cell proliferation. In contrast, up-regulation of GPC3 is often observed in hepatoma, neuroblastoma, and Wilms' tumor. Whether GPC3 plays the same growth inhibitory role in these tumors remains to be studied. Here we report that antisense-mediated knockdown of GPC3 in the HepG2 hepatoma cells significantly promotes the growth of hepatoma cells. In addition, we show that this growth promotion is independent of insulin-like growth factor 2 (IGF2) signaling. Our data suggest that GPC3 plays a growth-suppressing role in hepatoma and provide cell biological evidence inconsistent with the hypothesis that GPC3 acts as a growth suppressor by downregulating IGF2.