Apoptotic activity of frog Bombina maxima skin albumin

Albumin, the most abundant protein components of blood plasma, is synthesized and secreted by liver cells in vertebrates. Recently, it was demonstrated that frog Bombina maxima albumin is also expressed in skin. Both B. maxima albumins from skin and serum (BmA-skin and BmAserum) have similar biochemical characteristics except that the former contains haem b. Present studies showed that BmA-skin exhibited cytotoxic activity on H9 and C8166 cells. Pretreated with hemin to induce erythroid differentiation, K562 cells lost their resistance to cytotoxicity of BmAskin. After treating cells with BmA-skin for 48 h, 50 percentage cytotoxic concentrations (CC50) of BmA-skin on H9, C8166 and hemin-treated K562 cells were 1.31±0.09, 1.59±0.08 and 2.28±0.06 μM, respectively. The cell death induced by BmA-skin was mediated by apoptosis of the tested cell lines, as demonstrated by nuclear morphological changes, DNA fragmentation and DNA hypodiploidy of apoptosis cells. At BmA-skin concentration of 2 μM, 27.3%, 19.7% and 17.8% of H9, C8166 and hemin-treated K562 cells were found to be apoptotic. In contrast, BmA-serum possessed no cytotoxic and apoptosis-inducing activity on all the cell lines tested, even with concentration used up to 15 μM. These results indicated that bound haem b in BmA-skin contributed significantly to its cytotoxic and apoptosis-inducing activity on the cell lines assayed.

A new potential radiosensitizer- multi-walled carbon nanotubes modified by ammonium persulfate

Here we prepare carbon nanotubes modified with ammonium persulfate, very short carbon nanotubes with 50-100 nanometer length was obtained, and the higher P potential of 52 mV was detected, these supporting the successful modification. HeLa cells were irradiated with P rays via adding or absent above functionalized carbon nanotubes (f- WCNTs) into cell culture medium with different concentration and radiation dosage. Confocal microscopy images and fluorescence-labeled DNA detection verified the successfully pure multi-walled carbon nanotubes (p-WCNTs) and f-WCNTs penetrated into cells. Compared with pure radiation, by MTT test, f-WCNTs induced cell death markedly with about 8.7 times higher than former one under little dose of radiation; meanwhile, no obvious toxicity was observed both in p-WCNTs and f-WCNTs without of radiation exposure. We hypothesized that large amount of hydroxyl and carbonyl organs on the surface of very short f-WCNTs changed into free radicals result from radiations led cell damage. These implied that f-WCNTs could be regarded as a new radiosensitizer.

Effects of Ionizing Radiation on Three-Dimensional Human Vessel Models: Differential Effects According to Radiation Quality and Cellular Development

Little is known about the effects of space radiation on the human body. There are a number of potential chronic and acute effects, and one major target for noncarcinogenic effects is the human vasculature. Cellular stress, inflammatory response, and other radiation effects on endothelial cells may affect vascular function. This study was aimed at understanding the effects of space ionizing radiation on the formation and maintenance of capillary-like blood vessels. We used a 3D human vessel model created with human endothelial cells in a gel matrix to assess the effects of low-LET protons and high-LET iron ions. Iron ions were more damaging and caused significant reduction in the length of intact vessels in both developing and mature vessels at a dose of 80 cGy. Protons had no effect on mature vessels up to a dose of 3.2 Gy but did inhibit vessel formation at 80 cGy. Comparison with gamma radiation showed that photons had even less effect, although, as with protons, developing vessels were more sensitive. Apoptosis assays showed that inhibition of vessel development or deterioration of mature vessels was not due to cell death by apoptosis even in the case of iron ions. These are the first data to show the effects of radiation with varying linear energy transfer on a human vessel model. (C) 2011 In Radiation Research Society

Knocking-Down Cyclin A(2) by siRNA Suppresses Apoptosis and Switches Differentiation Pathways in K562 Cells upon Administration with Doxorubicin

Cyclin A(2) is critical for the initiation of DNA replication, transcription and cell cycle regulation. Cumulative evidences indicate that the deregulation of cyclin A(2) is tightly linked to the chromosomal instability, neoplastic transformation and tumor proliferation. Here we report that treatment of chronic myelogenous leukaemia K562 cells with doxorubicin results in an accumulation of cyclin A(2) and follows by induction of apoptotic cell death. To investigate the potential preclinical relevance, K562 cells were transiently transfected with the siRNA targeting cyclin A(2) by functionalized single wall carbon nanotubes. Knocking down the expression of cyclin A(2) in K562 cells suppressed doxorubicin-induced growth arrest and cell apoptosis. Upon administration with doxorubicin, K562 cells with reduced cyclin A(2) showed a significant decrease in erythroid differentiation, and a small fraction of cells were differentiated along megakaryocytic and monocyte-macrophage pathways. The results demonstrate the pro-apoptotic role of cyclin A(2) and suggest that cyclin A(2) is a key regulator of cell differentiation.

Capillary liquid chromatographic-high-resolution mass spectrometric analysis of ribonucleotides

A method of capillary HPLC-high-resolution MS was developed for the trace analysis of ATP, GTP, dATP and dGTP Dimethylhexylamine (DMHA) was used as ion-pairing agent for the HPLC retention and separation of the nucleotides and positive ion electrospray time-of-flight MS was used for the detection. The application of capillary HPLC allowed minimal usage of DMHA while providing excellent peak retention and resolution, which significantly reduced the ion suppression in electrospray ionization-MS analysis and thus increased the sensitivity. Adduct ions of nucleotides and DMHA were used as quantitative ions in order to achieve the best sensitivity. DMHA concentration at 5 mM in the aqueous mobile phase at pH 7 was found to be the optimal conditions for the C Is capillary column. The method was applied to determine ATP level in cultured C6 glioma cells that were treated with toxic concentrations of Zn. The results showed that the cellular ATP level decreased from 2.7 pmol/cell (<10% cell death) in average control cell samples to 0.36 pmol/cell as the concentration of Zn increased to 120 mg/l (>35% cell death) in culture medium.

The experimental research of R-phycoerythrin subunits on cancer treatment: A new photosensitizer in PDT

The mouse tumor cell 5180 and human liver carcinoma cell SMC 7721 cells were first treated with R-PE and its subunits (alpha, beta, gamma subunits), then irradiated with Argon laser (496 nm, 28.8 J/cm(2)). Survival rate was measured by MTT method. In order to compare the phototoxicity in normal cells, the mouse marrow cells were treated with photofrin II and beta-subunit, irradiated with 45 J/cm(2) of light; survival rate was also measured by MTT method. The result showed that R-PE subunits had better PDT effect on s180 cells than R-PE and lower phototoxicity in marrow cells than photofrin II Flow cytometric analysis showed that PDT results in a growth inhibition and a G(0)-G(1) cell cycle arrest in SMC 7721 cells. The tumor cells inhibited by PDT in vivo were morphologically observed by TEM, the tumor cell death was daze to the occlusion of tumor blood vessels and inducement of cell programmed death in nuclei. Therefore, with the advantage in special fluorescence activity, loth molecular weight, good light absorbent character and weak phototoxicity, R-PE subunit is art attractive option for improving the selectivity of PDT.

Microfluidic devices for the analysis of apoptosis

Apoptosis is the outcome of a metabolic cascade that results in cell death in a controlled manner. Due to its important role in maintaining balance in organisms, in mechanisms of diseases, and tissue homeostasis, apoptosis is of great interest in the emerging fields of systems biology. Research into cell death regulation and efforts to model apoptosis processes have become powerful drivers for new technologies to acquire ever more comprehensive information from cells and cell populations. The microfluidic technology promises to integrate and miniaturize many bioanalytical processes, which offers an alternative platform for the analysis of apoptosis. This review aims to highlight the recent developments of microfluidic devices in measuring the hallmarks as well as the dynamic process of cellular apoptosis. The potential capability and an outlook of microfluidic devices for the study of apoptosis are addressed.