[Inhibitory Effect of Ascorbic Acid on Myelodysplastic Syndrome Cells and Its Mechanism].

OBJECTIVE: To investigate the inhibitory effect of ascorbic acid single or combination of decitabine on tumor cells of myelodysplastic syndrome (MDS) and explore its related mechanism. METHODS: The human MDS cell lines SKM-1 and MUTZ-1 were treated with different concentrations of ascorbic acid, and the cell proliferation activity was detected by the CCK-8 assay. The reactive oxygen species (ROS) level, labile iron pool (LIP), cell cycle, and apoptosis of SKM-1 and MUTZ-1 cells were detected by flow cytometry. The control group, ascorbic acid monotherapy group, decitabine monotherapy group, and combination group of ascorbic acid and decitabine were set up, the cell proliferation activity and apoptosis were detected in each group. RESULTS: High-dose ascorbic acid could reduce the cell proliferation activity of SKM-1 (R=0.886, p=0.000) and MUTZ-1 (R=0.880, p=0.000). With the increase of ascorbic acid concentration, the ROS level in SKM-1 and MUTZ-1 cells increased (r=0.816, r=0.942), the proportion of cells stagnation in G2 phase increased (r=0.970, p=0.000; r=0.962, p=0.000), the proportion of surviving cells decreased (r=-0.966, p=0.000; r=-0.952, p=0.000), and the apoptosis cells significantly increased (r=0.966, p=0.000; r=0.958, p=0.000). Nevertheless, the level of LIP showed no significant changes. After the combined application of ascorbic acid and decitabine, MDS tumor cells showed decreased proliferative activity and increased apoptosis compared with single-agent ascorbic acid and decitabine group. CONCLUSION: High-dose ascorbic acid shows a cytotoxic effect on MDS tumor cells, inhibiting cell proliferation and increasing apoptosis. Ascorbic acid combined decitabine have a synergistic effect of anti-MDS tumor cells.

Inhibitory Effect of Ascorbic Acid on Myelodysplastic Syndrome Cells and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To investigate the inhibitory effect of ascorbic acid single or combination of decitabine on tumor cells of myelodysplastic syndrome (MDS) and explore its related mechanism.@*METHODS@#The human MDS cell lines SKM-1 and MUTZ-1 were treated with different concentrations of ascorbic acid, and the cell proliferation activity was detected by the CCK-8 assay. The reactive oxygen species (ROS) level, labile iron pool (LIP), cell cycle, and apoptosis of SKM-1 and MUTZ-1 cells were detected by flow cytometry. The control group, ascorbic acid monotherapy group, decitabine monotherapy group, and combination group of ascorbic acid and decitabine were set up, the cell proliferation activity and apoptosis were detected in each group.@*RESULTS@#High-dose ascorbic acid could reduce the cell proliferation activity of SKM-1 (R=0.886, p=0.000) and MUTZ-1 (R=0.880, p=0.000). With the increase of ascorbic acid concentration, the ROS level in SKM-1 and MUTZ-1 cells increased (r=0.816, r=0.942), the proportion of cells stagnation in G@*CONCLUSION@#High-dose ascorbic acid shows a cytotoxic effect on MDS tumor cells, inhibiting cell proliferation and increasing apoptosis. Ascorbic acid combined decitabine have a synergistic effect of anti-MDS tumor cells.

New light in the dark - a proposed multidisciplinary framework for studying functional ecology of groundwater fauna.

Groundwaters provide the vast majority of unfrozen freshwater resources on the planet, but our knowledge of subsurface ecosystems is surprisingly limited. Stygofauna, or stygobionts -subterranean obligate aquatic animals - provide ecosystem services such as grazing biofilms and maintaining water quality, but we know little about how their ecosystems function. The cryptic nature of groundwaters, together with the high degree of local endemism and stygofaunal site-specific adaptations, represent major obstacles for the field. To overcome these challenges, and integrate biodiversity and ecosystem function, requires a holistic design drawing on classical ecology, taxonomy, molecular ecology and geochemistry. This study presents an approach based on the integration of existing concepts in groundwater ecology with three more novel scientific techniques: compound specific stable isotope analysis (CSIA) of amino acids, radiocarbon analysis (14C) and DNA analyses of environmental samples, stygofauna and gut contents. The combination of these techniques allows elucidation of aspects of ecosystem function that are often obscured in small invertebrates and cryptic systems. Carbon (δ13C) and nitrogen (δ15N) CSIA provides a linkage between biogeochemical patterns and ecological dynamics. It allows the identification of stygofaunal food web structures and energy flows based on the metabolic pathway of specific amino groups. Concurrently, 14C provides complementary data on the carbon recycling and incorporation within the stygobiotic trophic webs. Changes in groundwater environmental conditions (e.g. aquifer recharge), and subsequent community adaptations, can be pinpointed via the measurementof the radiocarbon fingerprint of water, sediment and specimens. DNA analyses are a rapidly expanding approach in ecology. eDNA is mainly employed as a biomonitoring tool, while metabarcoding of individuals and/or gut contents provides insight into diet regimes. In all cases, the application of the approaches in combination provides more powerful data than any one alone. By combining quantitative (CSIA and 14C) and qualitative (eDNA and DNA metabarcoding) approaches via Bayesian Mixing Models (BMM), linkages can be made between community composition, energy and nutrient sources in the system, and trophic function. This suggested multidisciplinary design will contribute to a more thorough comprehension of the biogeochemical and ecological patterns within these undervalued but essential ecosystems.

Human occupation of northern Australia by 65,000 years ago.

The time of arrival of people in Australia is an unresolved question. It is relevant to debates about when modern humans first dispersed out of Africa and when their descendants incorporated genetic material from Neanderthals, Denisovans and possibly other hominins. Humans have also been implicated in the extinction of Australia's megafauna. Here we report the results of new excavations conducted at Madjedbebe, a rock shelter in northern Australia. Artefacts in primary depositional context are concentrated in three dense bands, with the stratigraphic integrity of the deposit demonstrated by artefact refits and by optical dating and other analyses of the sediments. Human occupation began around 65,000 years ago, with a distinctive stone tool assemblage including grinding stones, ground ochres, reflective additives and ground-edge hatchet heads. This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans.

N-(4-{[4-(1H-Benzoimidazol-2-yl)-arylamino]-methyl}-phenyl)-benzamide derivatives as small molecule heparanase inhibitors.

A novel class of N-(4-{[4-(1H-benzoimidazol-2-yl)-arylamino]-methyl}-phenyl)-benzamides are described as inhibitors of the endo-beta-glucuronidase heparanase. Among them are N-(4-{[4-(1H-benzoimidazol-2-yl)-phenylamino]-methyl}-phenyl)-3-bromo-4-methoxy-benzamide (15h), and N-(4-{[5-(1H-benzoimidazol-2-yl)-pyridin-2-ylamino]-methyl}- phenyl)-3-bromo-4-methoxy-benzamide (23) which displayed good heparanase inhibitory activity (IC(50) 0.23-0.29 microM), with the latter showing oral exposure in mice.

Heterodimer formation is essential for heparanase enzymatic activity.

Heparanase is an endo-beta-D-glucuronidase involved in cleavage of heparan sulfate residues and hence participates in extracellular matrix degradation and remodeling. The heparanase cDNA encodes for a polypeptide of 543 amino acids that appears as a approximately 65 kDa band in SDS-PAGE analysis. The protein undergoes a proteolytic cleavage that is likely to occur at two potential cleavage sites, Glu(109)-Ser(110) and Gln(157)-Lys(158), yielding an 8 kDa polypeptide at the N-terminus, a 50 kDa polypeptide at the C-terminus, and a 6 kDa linker polypeptide that resides in-between. The active form of heparanase has long been thought to be a 50 kDa polypeptide isolated from cells and tissues. However, attempts to obtain heparanase activity after expression of the 50 kDa polypeptide failed, suggesting that the N-terminal region is important for heparanase enzymatic activity. It has been hypothesized that heterodimer formation between the 8 and 50 kDa heparanase subunits is important for heparanase enzymatic activity. By individually or co-expressing the 8 and 50 kDa heparanase subunits in mammalian cells, we demonstrate specific association between the heparanase subunits by means of co-immunoprecipitation and pull-down experiments. Moreover, a region in the 50 kDa heparanase subunit that mediates interaction with the 8 kDa subunit was identified. Altogether, our results clearly indicate that heterodimer formation is necessary and sufficient for heparanase enzymatic activity in mammalian cells.