QGY Cells Research Articles

Shelterin differentially respond to oxidative stress induced by TiO2-NPs and regulate telomere length in human hepatocytes and hepatocarcinoma cells in vitro

Titanium dioxide nanoparticles (TiO2-NPs) have raised serious attention for their widely use and potential adverse effects on human mainly due to producing ROS. However, the influence of TiO2-NPs on telomere maintaining has not been studied clearly. Shelterin plays core roles in telomere length (TL) regulation. Abnormal TL are associated with chromosome instability (CIN) and high risk of diseases. This study investigated whether TiO2-NPs affect TL to induce CIN through ROS generation and the possible mechanisms. Human hepatocyte L-02 and hepatocarcinoma cells QGY were exposed to TiO2-NPs (0, 40, 80 μg/mL) for 72 h. The intracellular hydrogen dioxide (H2O2) concentration were measured. The TL, Nrf-2, and three core shelterin components (TRF1, TRF2, and POT1) transcription level were determined by quantitative real-time PCR. CIN was measured by cytokinesis-block micronucleus assay. TiO2-NPs exposure increased intracellular H2O2 in both L-02 and QGY cells, and induced Nrf-2, TRF1, TRF2, POT1 downregulated transcription compared with control (P < 0.001) in L-02 but all upregulated (P < 0.05) in QGY. Significant TL shortening (P < 0.001) and CIN increase (P < 0.01) in L-02 cells were observed but not in QGY cells. The differentially responses of the tested components of shelterin and Nrf-2 to oxidative stress induced by TiO2-NPs led to the weakened telomere protection in normal cells and effective telomere maintenance in cancer cells, respectively. The upregulation of Nrf-2 and shelterin could protect TL and chromosome stability against TiO2-NPs exposure.

Sperm-associated antigen 9 is upregulated in hepatocellular carcinoma tissue and enhances QGY cell proliferation and invasion in vitro.

The incidence and mortality rates of hepatocellular carcinoma (HCC) are higher in China compared with in other countries. Further research is required in order to improve the diagnosis and treatment of HCC. Sperm-associated antigen 9 (SPAG9) protein has been revealed to serve an important function in cancer progression; however, the underlying mechanisms remain to be elucidated. The present study investigated the expression level of SPAG9 in HCC tissues using quantitative-polymerase chain reaction, immunohistochemistry and western blotting, and the results demonstrated that SPAG9 was overexpressed in HCC tissues compared with the adjacent non-cancerous tissues. To explore the potential mechanisms underlying SPAG9 in HCC, the effect of SPAG9 on cell proliferation, cell cycle, migration and invasion capacities were investigated in the QGY HCC cell line by RNA interference. It was revealed that inhibition of SPAG9 mRNA in QGY cells significantly inhibited the expression level of SPAG9 compared with the control. Depletion of SPAG9 expression decreased cell proliferation (P<0.01) and increased the percentage of cells in the G1/G2 cell cycle phase. The percentage of cells in the S phase was decreased, and cell migration and invasion capabilities in vitro were reduced (P<0.01). In summary, the results of the present study suggested that SPAG9 was upregulated in HCC and may serve an important function in cancer cell proliferation, differentiation and invasion. Whether SPAG9 is a potential diagnostic marker and therapeutic target of human HCC requires additional study.

Gallium Phthalocyanine Photosensitizers: Carboxylation Enhances the Cellular Uptake and Improves the Photodynamic Therapy of Cancers

The octacarboxyl gallium (GaPcC) and metal-free (H2PcC) phthalocyanines were prepared using the carboxyl as the peripheral substituent. The carboxylation improves the intracellular delivery of these two PcCs into KB and QGY cancer cells as compared to that of sulfonated aluminum phthalocyanines (AlPcS), a popularly used photosensitizer (PS). Moreover, GaPcC maintains high photoproduction of singlet oxygen. With a short incubation time of 3 hours, GaPcC accumulates sufficiently in both KB and QGY cells and improves photodynamic therapy (PDT) by effectively killing these cancer cells. AlPcS and H2PcC show much lower PDT effects under the same conditions, because AlPcS have a slow cellular uptake rate resulting in a low cellular amount and the ability of H2PcC to produce 1O2 is low. Carboxylation is a promising way to prepare water-soluble metal phthalocyanines (MPcCs) and facilitates the cellular uptake of MPcCs for PDT improvement.

Hepatoma Cell Growth Inhibition by Inducing Apoptosis with Polysaccharide Isolated from Turkey Tail Medicinal Mushroom, Trametes versicolor (L.: Fr.) Lloyd (Aphyllophoromycetideae)

The Trametes (=Coriolus) versicolor polysaccharide (CVP) is well known as an anti-tumor drug in clinical applications. Although recent studies have demonstrated that CVPs can inhibit the proliferation of cancer cells in vitro and in vivo, different purity levels of CVPs have a different affect on various cancer cells. In this study, crude CVPs were extracted and purified from T. versicolor dry fruit bodies by hot-water extraction, ethanol precipitation, and phenol-vitriolic colorimetry. The in vitro cytotoxic activities of CVPs were examined on the human hepatoma cancer (QGY) cell lines by using an MTT assay. The cell cycle and cell death (apoptosis) of QGY cells were investigated by flow cytometry. The expression of genes involved in the apoptosis process, such as p53, Bcl-2, and Fas, was also studied using reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. These results showed that CVPs inhibited the proliferation of QGY in low concentrations (<20 mg/L) and the IC50 value was 4.25 mg/L. Changes that are characteristic of apoptosis, such as a found trapezoidal belt with DNA, were observed in the QGY cells treated with CVPs. There was a significant decrease in the expression of the cell cycle-related genes (p53, Bcl-2, and Fas,) in these cells following treatment with CVPs. These results thus indicate that CVPs can be a potential candidate to ameliorate toxic effects when used in cancer therapy.

Thiol-Capped CdTe Quantum Dots with Two-Photon Excitation for Imaging High Autofluorescence Background Living Cells

To effectively image living cells with quantum dots (QDs), particularly for those cells containing high content of native fluorophores, the two-photon excitation (TPE) with a femto-second 800 nm laser was employed and compared with the single-photon excitations (SPE) of 405 nm and 488 nm in BY-2 Tobacco (BY-2-T) and human hepatocellular carcinoma (QGY) cells, respectively. The 405 nm SPE produced the bright photoluminescence (PL) signals of cellular QDs but also induced a strong autofluorescence(AF) from the native fluorophores like flavins in cells. The AF occupied about 30% and 13% of the total signals detected in QD imaging channel in the BY-2-T and QGY cells, respectively. With the excitation of 488 nm SPE, the PL signals were lower than those excited with the 405 nm SPE, although the AF signals were also reduced. The 800 nm TPE generated the best PL images of intracellular QDs with the highest signal ratio of PL to AF, because the two-photon absorption cross section of QDs is much higher than that of the native fluorophores. By means of the TPE, the reliable cellular imaging with QDs, even for the cells having the high AF background, can be achieved.

Mechanism of suppression on proliferation of QGY cell by oxaliplatin

ObjectiveTo observe the effects of oxaliplatin(L-OHP) on proliferation of human hepatoma cell line QGY in vitro and to investigate the mechanism.MethodsThe inhibition of proliferation in QGY cell was assayed by MTT-test. Morphologic changes were observed under light microscope and electronic microscope. Distribution of cell cycle and apoptosis were analyzed using flow cytometry. The expressions of cell cycle proteins and apoptosis-associated proteins were detected with immuno-histochemical technique.ResultsOxaliplatin could inhibit the proliferation of QGY cells and the inhibition depended on the exposure time and dose. The cells showed morphologic changes of the early stage of apoptosis under the light microscope: the shrunk round cells, condensed cytoplasma and pycnosis of nucleus. Apoptotic cells and apoptotic body could be found under the transmission electronic microscope. The analysis of cell cycle indicated that oxaliplatin blocked cells at S and G2/M phases and the cells of G0/Gl phase reduced. When treated with oxaliplatin for 72h, the expressions of cyclin A and Bax were up-regulated, mutant type P53, Bcl-2 and Myc were down-regulated, and Fas was not changed.ConclusionOxaliplatin could inhibit the proliferation of the hepatoma cell lines. Cells were blocked at S and G2/M phases. The apoptosis was related to the up-regulation of Bax and down-regulation of mutant type P53, Bcl-2 and Myc. Oxaliplatin could not induce apoptosis through the Fas pathway.

Enhancement of Intracellular Delivery of CdTe Quantum Dots (QDs) to Living Cells by Tat Conjugation

Quantum dots (QDs), as novel fluorescence probes, have shown a great potential for bio-molecular labeling and cellular imaging. To stain cellular targets, the sufficient intracellular delivery of QDs is required. In this work the tat, a typical membrane-permeable carrier peptide, was conjugated with thiol-capped CdTe QDs to form CdTe Tat-QDs, and the intracellular deliveries of CdTe QDs or CdTe Tat-QDs were compared in human hepatocellular carcinoma (QGY) cells and human breast cancer (MCF7) cells in vitro by means of confocal laser scanning microscopy. Added into the cell dishes, both QDs and Tat-QDs adhered to the outer leaflet of the plasma membrane of cells within a few minutes, but the binding amount of Tat-QDs was obviously higher than that of QDs. Then both QDs and Tat-QDs can penetrate into cells, and their cellular contents increased with incubation time but both saturated after 3 hours incubation. However the cellular levels of Tat-QDs were higher than those of QDs, with the ratio of 2.1 (+/-0.3) times in QGY cells and 1.5 (+/-0.2) times in MCF7 cells, demonstrating the enhancing effect of Tat conjugation on the intracellular delivery of QDs.

Improvement of the photostability of thiol-capped CdTe quantum dots in aqueous solutionsand in living cells by surface treatment

The surface treatment of thiol-capped CdTe quantum dots (QDs)was carried out with a small amount of sodium borohydride(NaBH4) in aqueous solution at room temperature. The treatment effectively enhanced thephotostability of QDs and increased the photoluminescence (PL) efficiency by a factor oftwo as against the original ones. By measuring the PL trajectories of single QDs with atotal internal reflection fluorescence microscope under the same irradiation density of0.72 µW µm−2 at 532 nm, the photostable lifetimes were determined to be15.2 ± 5.9 s for surface-treatedQDs, and 5.8 ± 1.9 s for the original ones, respectively. Both the original and treated QDs couldbe ingested into human hepatocellular carcinoma cells (QGY) by incubation.The photobleaching of cellular QDs was measured with a confocal microscope.Remarkable enhancement was found for the photostability of the surface-treated QDsin QGY cells, demonstrating its advantage for cellular labelling applications.

TAXOL INDUCED BCL-2 PROTEIN PHOSPHORYLATION IN HUMAN HEPATOCELLULAR CARCINOMA QGY-7703 CELL LINE

Bcl-2 family proteins play a critical role in the regulation of apoptosis. Treatment of a human hepatocellular carcinoma cell line, QGY-7703, with Taxol induced apoptosis and Bcl-2 protein phosphorylation. Microscopic observation indicated that apoptotic bodies (0–15%) of Taxol-treated QGY cells appeared after 12h of treatment, and apoptotic QGY cells gradually increased to 40% after 24h and 70% after 48h. A DNA fragmentation assay showed that Taxol induced genomic DNA cleavage into 200bp DNA fragments. Bcl-2 protein was phosphorylated in Taxol-treated QGY cells within 3h of treatment, and continued gradually up to 24h. By 48h, the protein was unphosphorylated. Other Bcl-2 family proteins, including Bax (a heterodimerization partner of Bcl-2), Bcl-XL, Bak and Bad, were expressed, but at constant levels. The results show a close correlation between Bcl-2 phosphorylation and apoptosis in QGY cells. The inactivation of Bcl-2 protein phosphorylation could be one of the key mechanisms needed for the induction of apoptosis in Taxol-treated QGY cells.