5 research outputs found
Silvestrol induces early autophagy and apoptosis in human melanoma cells
BACKGROUND: Silvestrol is a cyclopenta[b]benzofuran that was isolated from the fruits and twigs of Aglaia foveolata, a plant indigenous to Borneo in Southeast Asia. The purpose of the current study was to determine if inhibition of protein synthesis caused by silvestrol triggers autophagy and apoptosis in cultured human cancer cells derived from solid tumors. METHODS: In vitro cell viability, flow cytometry, fluorescence microscopy, qPCR and immunoblot was used to study the mechanism of action of silvestrol in MDA-MB-435 melanoma cells. RESULTS: By 24 h, a decrease in cyclin B and cyclin D expression was observed in silvestrol-treated cells relative to control. In addition, silvestrol blocked progression through the cell cycle at the G(2)-phase. In silvestrol-treated cells, DAPI staining of nuclear chromatin displayed nucleosomal fragments. Annexin V staining demonstrated an increase in apoptotic cells after silvestrol treatment. Silvestrol induced caspase-3 activation and apoptotic cell death in a time- and dose-dependent manner. Furthermore, both silvestrol and SAHA enhanced autophagosome formation in MDA-MB-435 cells. MDA-MB-435 cells responded to silvestrol treatment with accumulation of LC3-II and time-dependent p62 degradation. Bafilomycin A, an autophagy inhibitor, resulted in the accumulation of LC3 in cells treated with silvestrol. Silvestrol-mediated cell death was attenuated in ATG7-null mouse embryonic fibroblasts (MEFs) lacking a functional autophagy protein. CONCLUSIONS: Silvestrol potently inhibits cell growth and induces cell death in human melanoma cells through induction of early autophagy and caspase-mediated apoptosis. Silvestrol represents a natural product scaffold that exhibits potent cytotoxic activity and could be used for the further study of autophagy and its relationship to apoptosis in cancer cells. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-015-1988-0) contains supplementary material, which is available to authorized users
Changes to the physical properties of the soil after the passage of an agricultural tractor
The effect of the passage of agricultural machinery
on the soil is influenced by, for example, the inflation pressure
in tyres. This article describes the effect of different tyre inflation
pressures (200 and 100 kPa) on selected physical soil properties in
the field experiment. The undisturbed samples were collected both
in and between the tracks at depths of 0 to 0.5 m and subsequently
processed according to a valid methodology in the laboratory. The
results indicate that fewer negative changes were found in the
variant with a lower inflation pressure for all of the observed soil
properties (front wheels load 2 990 kg and rear wheels 11 760 kg).
However, the differences between the pressures were not statistically
significant. The impact of different tyre pressures at greater
depths has also not been proven to date. This may be attributed to
the creation of a plough pan due to the long-term use of the minimization
technique because the values of individual properties
were balanced at a depth of 0.2 to 0.3 m. These depths do not react
to further tractor compaction due to the accumulation of compaction.
Changes to the values of soil physical properties caused by
the passage of the tractor were statistically significant for both tyre
pressure variants only at depths ranging from 0 to 0.1 m