Effect of taurine on cell proliferation and apoptosis human lung cancer A549 cells.

To investigate the effects of taurine on cell proliferation and apoptosis, the human lung cancer A549 cell line and xenograft tumors in nude mice were used. The effects of taurine on cell proliferation and apoptosis were observed at time points of 24, 48 and 72 h after treatment using an MTT assay to detect the survival rate, and flow cytometry to detect the apoptotic rate. Western blot analysis was performed to examine the levels of p53 upregulated modulator of apoptosis (PUMA), BCL2, apoptosis regulator (Bcl-2) and BCL2-associated X, apoptosis regulator (Bax) in A549 cells. The level of PUMA, Bax and Bcl-2 proteins in the mouse xenograft tumors treated with taurine and/or exogenous PUMA were assessed by immunohistochemistry, with taurine suppressing the proliferation of the human lung cancer A549 cell line in a concentration-dependent manner, and it significantly enhanced the apoptosis rate at all concentrations. Taurine induced the significant upregulation of PUMA and Bax, but led to downregulation of Bcl-2. In comparison to the control group, taurine treatment markedly reduced the volume and weight of A549-derived xenograft tumors in nude mice. Expression of PUMA and Bax were upregulated in the xenograft tumors following taurine treatment, whereas Bcl-2 was downregulated. In addition, the inhibitory effect of taurine and exogenous PUMA on tumor growth was significantly higher than that of a single treatment of taurine or exogenous PUMA. It can therefore be concluded that taurine can inhibit cell proliferation of the human lung cancer A549 cell line and the growth of the xenograft tumors, whereas PUMA serves an important role in taurine-induced growth suppression.

[Studies on the properties of frequency upconversion of Yb3+/Er3+ codoped absolute oxides].

Samples of Er+3/Yb3+ codoped 3CaO-Al2O3-3SiO2 compounds were prepared, and the properties of frequency upconversion of the samples under the excitation of 980 nm diode laser were studied. Green and red emissions centered at 523, 547 and 656 nm, corresponding to the transitions 2H(11/2)-->4I(15/2), 4S(3/2)-->4I(15/2), and 4F(9/2)-->4I(15/2), respectively, were observed. The dependence of the upconversion fluorescence intensity on the pumping power, and the phonon energy of each sample were observed, and the mechanism of frequency upconversion based on these two items was discussed.