Inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 and its mechanism / 中国实验血液学杂志

This study was aimed to investigate the inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 cells and its possible mechanism. The inhibition effect of brucine on growth of THP-1 cells was measured by CCK-8 method. Morphological changes of THP-1 cells treated with brucine was detected by acridine orange/ethidium bromide (AO/EB)double staining. Annexin-V/PI double labeling method was used to assay the apoptosis rate of THP-1 cells. The effect of brucine on THP-1 cell cycle distribution was detected by PI single staining. RT-PCR was used to detect the expression of BCL-2 and BAX. The results showed that the brucine could inhibit the THP-1 cell growth in concentration and time-dependent manners at the range of 50 to 400 µg/ml. The cells stained with AO/EB revealed that the brucine induced the nuclear chromatin condensation. After the THP-1 cells were treated with brucine of 400µg/ml for 48 hours, most nucleic were stained as orange-red, and condensed, displaying the late apoptotic cell morphology. Annexin-V/PI detection showed that brucine could induce apoptosis of THP-1 cells in a concentration-dependent manner. Compared with the control group, more cells in brucine-treated group were arrested at G0/G1 phase in a concentration-dependent manner. RT-PCR detection revealed that the expression of BCL-2 was down-regulated strikingly and BAX was up-regulated. It is concluded that brucine can efficiently inhibit cell growth and block THP-1 cells in G0/G1 phase. The mechanism of THP-1 cell apoptosis induced by brucine may be related to the inhibition of BCL-2 and activation of BAX.

A new photodynamic therapy drug toward gastric cancer MGC803 cell / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the treatment efficiency of a new photodynamic therapeutic(PDT) drug synthesized by our laboratory toward MGC803 cells and related mechanisms.</p><p><b>METHODS</b>Bleaching method was used to evaluate the photostability of drug upon repetitive illumination. MTT assay was used to determine the ability of new drug killing MGC803 cells after PDT. Laser scanning confocal microscopy (LSCM) was applied to investigate the subcellular localization of drug in MGC803 cells (mitochondria and/or lysosomes). Hoechst staining and flow cytometry(Annexin V/PI double-staining) were performed to detect the death mode of MGC803 cells after PDT.</p><p><b>RESULTS</b>This new PDT drug had good stability to light irradiation after repetitive illumination. MTT assay showed no cytotoxicity towards MGC803 cells only by drug or only by irradiation(P>0.05), but intense lethal effect was observed with drug and light combination(P<0.05). The phototoxicity of medicine increased with the elevation of concentration, the LD50 was 1.74 μmol/L, and reaching plateau at the concentration of 3.12 μmol/L, even increasing the concentration. LSCM found that drug localized in lysosomes of MGC803 cells. Hoechst staining showed that the death mode of cells was mainly necrosis and Annexin V/PI double-staining proved this result further.</p><p><b>CONCLUSION</b>This new PDT drug is an effective PDT sensitizer for MGC803 cells and the death mode of cells is mainly necrosis.</p>

Effect of brucine on secretion function and proliferation capability of T lymphocytes in patients with aplastic anemia / 中国实验血液学杂志

The aim of this study was to investigate the effect of brucine on secretion of TNF-α, IFN-γ, IL-4 and proliferation of T lymphocytes in patients with aplastic anemia (AA), and to explore its mechanism. Peripheral blood T lymphocytes from 10 patients with AA and 10 healthy volunteers were isolated, purified and cultured. T lymphocytes from the patients were divided into 0, 100, 200 and 400 µg/ml brucine-treated groups. T lymphocytes from healthy volunteers were used as control group. After being cultured for 72 hours, the levels of TNF-α, IFN-γ, IL-4 in the supernatant of cultured T lymphocytes from AA patients were detected by ELISA, and the proliferation of T lymphocytes from AA patients was detected by MTT. The results showed that compared with the normal control group, the levels of TNF-α and IFN-γ in the culture supernatant significantly increased, and IL-4 was significantly decreased. The levels of TNF-α and IFN-γ in the culture supernatant of brucine treated groups were lower, and were dependent on the concentration of brucine. However, the levels of IL-4 were found to be not obviously changed. The inhibition rate of T lymphocytes in 100, 200 and 400µg/ml brucine-treated groups were (13.61 ± 4.31)%, (14.28 ± 4.31)% and (15.12 ± 4.56)% respectively, among which the differences were not statistically significant. It is concluded that the brucine can reduce the levels of TNF-α and IFN-γ through inhibiting the proliferation of T lymphocytes in AA patients, which provides experimental basis for therapy of AA patients.

Effect of β-catenin gene silencing by shRNA on biologic characteristics of human esophageal carcinoma cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the effects of short hairpin RNA (shRNA) mediated gene silencing of β-catenin on the biological characteristics of esophageal carcinoma cells, and to provide theoretical and experimental evidence for the gene therapy of esophageal carcinoma through target inhibition of β-catenin gene.</p><p><b>METHODS</b>Single strand DNA was synthesized according to the hairpin RNA sequence, and then subcloned into eukaryotic expression vector pGenesil-3 to construct a shRNA-expression pDNAs driven by human U6 promoter of β-catenin (pGen-3-CTNNB1). One additional construct of random siRNA (pGen-3-con) without homologous to any human genes was constructed in a similar fashion as control.Positive clones were identified and verified by restriction cleavage and DNA sequencing analyses. pGen-3-CTNNB1 and pGen-3-con were then transfected into esophageal carcinoma cell line Eca-109 with liposome, respectively. Positive colonies were selected with G418. Expression of β-catenin protein and mRNA in the transfected and nontransfected Eca-109 cells were examined by Western blotting, immunofluorescence and RT-PCR, respectively. Xenograft tumor model was used to compare the tumorigenesis of three different cells.Expressions of β-catenin in all tumor tissues were examined by immunohistochemistry staining. The invasive abilities of three different cells were examined with transwell invasion filter and Matrigel.</p><p><b>RESULTS</b>β-catenin expression levels were found markedly decreased in Eca-109 cells transfected with pGen-3-CTNNB1. In vivo, transfection with β-catenin shRNA greatly impeded the tumor growth, pGen-3-con (1.18 ± 0.13) g, Eca-109 (1.38 ± 0.21) g, pGen-3-CTNNB1 (0.42 ± 0.09) g, P < 0.05. Immunohistochemistry staining showed a significantly decreased expression of β-catenin in β-catenin shRNA transfected cells than in random shRNA transfected and nontransfected cells (P < 0.05). The infiltration abilities of esophageal carcinoma cells were significantly suppressed, pGen-3-con (81 ± 5)/HPF, Eca-109 (77 ± 6)/HPF, pGen-3-CTNNB1 (41 ± 4)/HPF, P < 0.01; along with significantly decreased migration abilities, pGen-3-con (73 ± 5)/HPF, Eca-109 (69 ± 5)/HPF, pGen-3-CTNNB1 (38 ± 4)/HPF (P < 0.05).</p><p><b>CONCLUSIONS</b>There are abnormal expression of β-catenin and activation of Wnt signaling pathway in human esophageal carcinoma cell line Eca-109. RNA interference targeting β-catenin gene suppresses the growth of xenograft tumorigenesis in nude mouse and the invasiveness and metastatic capability of esophageal carcinoma cells.</p>