Evaluation of Silibinin Effects on the Viability of HepG2 (Human hepatocellular liver carcinoma) and HUVEC (Human Umbilical Vein Endothelial) Cell Lines.

Human hepatocellular carcinoma is one of the most common recurrent malignancies since there is no effective therapy for it. Silibinin, a widely used drug and supplement for various liver disorders, demonstrated anti-cancer effects on human hepatocellular carcinoma, human prostate adenocarcinoma cells, human breast carcinoma cells, human ectocervical carcinoma cells, and human colon cancer cells. Considering the anti-hepatotoxic activity of silibinin and its strong preventive and anti-cancer efficacy against various epithelial cancers, we investigated the efficacy of silibinin against human HCC and HUVEC cell lines. Silibinin effects on the growth and mode of cell death of these two cell lines are presented in this paper. HepG2 and HUVEC cells were incubated with different doses of silibinin (12.5, 25, 50, 100, 150 and 200 µg/mL) at 24, 48, and 72 h. Cytotoxicity was assessed using MTT and Trypan blue assays. Mode of cell death induced by silibinin was investigated using LDH assay and acridine orange/PI double dye staining. The results showed that silibinin has dose-dependent inhibitory effect on the viability of HepG2 and HUVEC cells. However, Silibinin causes a more continuous dose-dependent cytotoxicity in HepG2 cells compared to the HUVEC cells in which some degrees of resistance is apparent at the beginning. The mode of cell death looks also different in these two cell lines with HepG2 cells being more in favor of apoptosis while necrosis is more evident for the HUVEC cells.

The Time Course of JNK and P38 Activation in Cerebellar Granule Neurons Following Glucose Deprivation and BDNF Treatment.

Low glucose condition induces neuronal cell-death via intracellular mechanisms including mitogen-activated protein kinases (MAPK) signaling pathways. It has been shown that low glucose medium decreases neuronal survival in cerebellar granule neurons (CGNs). In this study, we have examined the activation of JNK, p38kinase and ERK1/2 pathways in low glucose medium in CGNs. The CGNs were prepared from new-born (P-2 and P-5) rats and cultured in Dulbecco's Modified Eagle's Medium high (DMEM-HIGH) glucose supplemented with Fetal Bovine Serum (FBS) 10% for 7 days. The glucose deprivation was induced through replacing the culture medium with the low glucose (5 mM) medium. The MAPK pathways activation was evaluated through phospho specific antibodies using western blot. The viability of cells was measuring using MTT assay. The results indicated that low glucose reduces the cell survival and brain-derived neurotrophic factor (BDNF) elevates the cell viability in CGNs. The basal c-Jun N-terminal kinase (JNK) activity was high in CGNs and glucose deprivation for 24 h had increased phospho-JNK level to 2-fold compared to basal. BDNF treatment reduced the basal JNK activity within 30 min but had no effect in longer incubations. BDNF also blocked the low glucose-induced JNK activation. In addition, CGNs exhibited high p38 phosphorylation in low glucose medium in 48 h. These results demonstrated that in sustained low glucose conditions, CGNs had high activity of stress-activated MAPK which could induce cellular damage. Moreover, BDNF can prevent JNK and p38 activation in stress conditions and increase cell viability. Our results suggest that in sustained stress conditions, inhibition of JNK and/or p38 pathways might protect neurons from damage in low glucose conditions.