Enhanced activation of PERK-ATF4 pathway by Brefeldin A and cisplatin in human lung cancer GLC-82 ;cells / 实用医学杂志

Objective To investigate the molecular mechanisms of synergistic effects of BFA and CDDP on human lung cancer GLC-82 cells, and to test the levels of PERK-ATF4 pathway. Methods GLC-82 cells were incubated with 50 ng/mL of BFA or/and 2 μg/mL of CDDP for 24 or 48 hours. The levels of PERK, p-PERK and ATF4 in GLC-82 were analyzed by real-time PCRand/or Western Blot. Results The levels of PERK were lowest in CDDP group, but higher in BFA group (P < 0.05), the highest in group of BFA+CDDP (P < 0.05 or P < 0.01). The p-PERK level decreased in group of BFA+CDDP (P < 0.05 or P < 0.01). There was no significant change of ATF4 expression in CDDP group, but ATF4 expression increased slightly in BFA group, and increased further in group of BFA+CDDP (P < 0.05 or P < 0.01)which was also higher than that in BFA group or CDDP group (P < 0.05 or P < 0.01). Conclusions The upregulated levels of PERK and ATF4 by the combination of BFA and CDDP may be one of the mechanisms of synergistic anti-cancer effect of BFA and CDDP on GLC-82 cells.

Baicalein protects HT22 murine hippocampal neuronal cells against endoplasmic reticulum stress-induced apoptosis through inhibition of reactive oxygen species production and CHOP induction

Baicalein is one of the major flavonoids in Scutellaria baicalensis Georgi and possesses various effects, including cytoprotection and anti-inflammation. Because endoplasmic reticulum (ER) stress has been implicated in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and cerebral ischemia, we investigated the effects of baicalein on apoptotic death of HT22 mouse hippocampal neuronal cells induced by thapsigargin (TG) and brefeldin A (BFA), two representative ER stress inducers. Apoptosis, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) were measured by flow cytometry. Expression level and phosphorylation status of ER stress-associated proteins and activation and cleavage of apoptosis-associated proteins were analyzed by Western blot. Baicalein reduced TG- and BFA-induced apoptosis of HT22 cells and activation and cleavage of apoptosis-associated proteins, such as caspase-12 and -3 and poly(ADP-ribose) polymerase. Baicalein also reduced the TG- and BFA-induced expression of ER stress-associated proteins, including C/EBP homologous protein (CHOP) and glucose-regulated protein 78, the cleavage of X-box binding protein-1 and activating transcription factor 6alpha, and the phosphorylation of eukaryotic initiation factor-2alpha and mitogen-activated protein kinases, such as p38, JNK, and ERK. Knock-down of CHOP expression by siRNA transfection and specific inhibitors of p38 (SB203580), JNK (SP600125), and ERK (PD98059) as well as anti-oxidant (N-acetylcysteine) reduced TG- or BFA-induced cell death. Baicalein also reduced TG- and BFA-induced ROS accumulation and MMP reduction. Taken together, these results suggest that baicalein could protect HT22 neuronal cells against ER stress-induced apoptosis by reducing CHOP induction as well as ROS accumulation and mitochondrial damage.

An Orthogonal Experiment in the Brefeldin a Fermentation of Pencillium / 微生物学通报

Through orthogonal experiment,the optimal conditions were given for producing extracellular BFA of Penicillium.Its optimal conditions were as follows(g/L): potato 200,glucose 20,(NH_(4))_(2)SO_(4) 4.0, KH_(2)PO_(4) 1.0,MgSO_(4)?7H_(2)O 2.0,CaCO_(3) 5.0,the pH was natural,culture medium volume 100mL/250mL,culture temperature 28℃,revolutions 120r/min and culture time 7 days.The biggest production of BFA was 151.6(mg/L.)