Polygalacin D inhibits the growth of hepatocellular carcinoma cells through BNIP3L-mediated mitophagy and endogenous apoptosis pathways.

Platycodon grandiflorum (Jacq.) A. DC. is a famous medicinal plant commonly used in East Asia. Triterpene saponins isolated from P. grandiflorum are the main biologically active compounds, among which polygalacin D (PGD) has been reported to be an anti-tumor agent. However, its anti-tumor mechanism against hepatocellular carcinoma is unknown. This study aimed to explore the inhibitory effect of PGD in hepatocellular carcinoma cells and related mechanisms of action. We found that PGD exerted significant inhibitory effect on hepatocellular carcinoma cells through apoptosis and autophagy. Analysis of the expression of apoptosis-related proteins and autophagy-related proteins revealed that this phenomenon was attributed to the mitochondrial apoptosis and mitophagy pathways. Subsequently, using specific inhibitors, we found that apoptosis and autophagy had mutually reinforcing effects. In addition, further analysis of autophagy showed that PGD induced mitophagy by increasing BCL2 interacting protein 3 like (BNIP3L) levels.In vivo experiments demonstrated that PGD significantly inhibited tumor growth and increased the levels of apoptosis and autophagy in tumors. Overall, our findings showed that PGD induced cell death of hepatocellular carcinoma cells primarily through mitochondrial apoptosis and mitophagy pathways. Therefore, PGD can be used as an apoptosis and autophagy agonist in the research and development of antitumor agents.

Lead exposure-induced cognitive impairment through RyR-modulating intracellular calcium signaling in aged rats.

Lead is widely distributed in the environment and has become a global public health issue. It is well known that lead exposure induces not only neurodevelopmental toxicity but also neurodegenerative diseases, with learning and memory impairment in the later stage. However, the molecular mechanisms remain elusive. The present study investigated the effects of early life and lifetime lead exposure on cognition and identified the molecular mechanisms involved in aged rats. The results herein demonstrated that the lead concentration in peripheral blood and brain tissues in aged rats was significantly increased in a lead dose-dependent manner. High-dose lead exposure caused cognitive functional impairment in aged rats, concomitant with a longer escape latency and a lower frequency of crossing the platform via Morris water maze testing compared to those in the control and low-dose lead exposure groups. Importantly, neuron functional defects were still observed even in early life lead exposure during the prenatal and weaning periods in aged rats. The neurotoxicity induced by lead exposure was morphologically evidenced by a recessed nuclear membrane, a swollen endoplasmic reticulum, and mitochondria in the neurons. Mechanistically, the exposure of aged rats to lead resulted in increasing free calcium concentration, reactive oxygen species, and apoptosis in the hippocampal neurons. Lead exposure increased RyR3 expression and decreased the levels of p-CaMKIIα/CaMKIIα and p-CREB/CREB in the hippocampus of aged rats. These findings indicated that early life lead exposure-induced cognition disorder was irreversible in aged rats. Lead-induced neurotoxicity might be related to the upregulation of RyR3 expression and high levels of intracellular free calcium with increasing lead concentration in injured neurons.

Discovery of novel AKT inhibitors with enhanced anti-tumor effects in combination with the MEK inhibitor.

Tumor cells upregulate many cell signaling pathways, with AKT being one of the key kinases to be activated in a variety of malignancies. GSK2110183 and GSK2141795 are orally bioavailable, potent inhibitors of the AKT kinases that have progressed to human clinical studies. Both compounds are selective, ATP-competitive inhibitors of AKT 1, 2 and 3. Cells treated with either compound show decreased phosphorylation of several substrates downstream of AKT. Both compounds have desirable pharmaceutical properties and daily oral dosing results in a sustained inhibition of AKT activity as well as inhibition of tumor growth in several mouse tumor models of various histologic origins. Improved kinase selectivity was associated with reduced effects on glucose homeostasis as compared to previously reported ATP-competitive AKT kinase inhibitors. In a diverse cell line proliferation screen, AKT inhibitors showed increased potency in cell lines with an activated AKT pathway (via PI3K/PTEN mutation or loss) while cell lines with activating mutations in the MAPK pathway (KRAS/BRAF) were less sensitive to AKT inhibition. Further investigation in mouse models of KRAS driven pancreatic cancer confirmed that combining the AKT inhibitor, GSK2141795 with a MEK inhibitor (GSK2110212; trametinib) resulted in an enhanced anti-tumor effect accompanied with greater reduction in phospho-S6 levels. Taken together these results support clinical evaluation of the AKT inhibitors in cancer, especially in combination with MEK inhibitor.

Bridging the gap between cytotoxic and biologic therapy with metronomic topotecan and pazopanib in ovarian cancer.

This study aimed to investigate the antitumor and antiangiogenic effects utilizing a novel therapy regimen of metronomic topotecan and pazopanib, a multireceptor tyrosine kinase inhibitor. In vitro (Western blot) and in vivo dose-finding experiments were done following pazopanib therapy in ovarian cancer models. Pazopanib and metronomic (daily) oral topotecan therapy was examined in an orthotopic model of ovarian cancer. Tumor weights, survival, and markers of the tumor microenvironment [angiogenesis (CD31 and pericyte coverage), proliferation (Ki-67), and apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling)] were analyzed by immunostaining following therapy. Pazopanib therapy reduced vascular endothelial growth factor receptor 2 (VEGFR-2) activity in vitro and vivo in a dose-dependent manner. Compared with control mice, pazopanib reduced tumor weight by 28% to 82% (P < 0.01 in the SKOV3ip1 model) and metronomic topotecan reduced tumor weight by 40% to 59% in the HeyA8 (P = 0.13) and SKOV3ip1 (P = 0.07) models. Combination therapy had the greatest effect with 79% to 84% reduction (P < 0.01 for both models). In the SKOV3ip1 and A2780 models, mouse survival was significantly longer (P < 0.001 versus controls) with pazopanib and metronomic topotecan therapy. Pazopanib therapy reduced murine endothelial cell migration in vitro in a dose-dependent manner following VEGF stimulation and decreased tumor microvessel density and pericyte coverage when given in combination with metronomic topotecan. Tumor cell proliferation decreased in all treatment arms compared with controls (P < 0.01 for combination groups) and increased tumor cell apoptosis by 4-fold with combination therapy. Pazopanib therapy in combination with metronomic topotecan therapy showed significant antitumor and antiangiogenic properties in preclinical ovarian cancer models and warrants further investigation as a novel therapeutic regimen in clinical trials. Mol Cancer Ther; 9(4); 985-95. (c)2010 AACR.

[Study on quality standard of Rhizoma Diosoreae and Rhizoma Dioscorea stir-baked with bran].

OBJECTIVE: To perfect the current standard of Rhizoma Diosoreae and Rhizoma Diosoreae stir-baked with bran by improving quality standards of the two processed pieces. METHOD: The quality standards were established according to 9 batches of processed pieces, separately. The standards contains items of identification, water, total ash, acid-insoluble ash, extractives, heavy metals limit, organochlorine limit, microbial limit and assay. RESULT: The TLC of the two pieces was characteristed. The contents of acid-insoluble ash in the two pieces were increased, not more than 0.5%, 0.3%, respectively. The content limits of five kinds of heavy metals and harmful elements, two kinds of residual organochlorine pesticides and three microbial limits were increased. There were no more than 2 x 10(-7) of lead, 2 x 10(-7) of cadmium, 1 x 10(-5) of copper, 3 x 10(-7) of arsenic, 1 x 10(-7) of mercury, 1 x 10(-7) of hexachlorocyclohexane (BHC) and 1 x 10(-7) of chlorophenothane (DDT) in the two processed pieces, respectively. There were no more than 2 000 and 600 cfu x mL(-1) in the two pieces, respectively and no more than 30 MPN x 100 g(-1) and fungi can not be tested in the two pieces. The contents of allantoin in the two pieces were no more than 0.15%. CONCLUSION: This method is simple and suitable for the quality control of the two processed pieces.

[Processing technics of Rhizoma Dioscoreae stired by wheat bran].

OBJECTIVE: To study the processing technics of prepared slice of Rhizoma Dioscoreae for its industrial production. METHOD: The effect factors, such as stiring temperature (60, 80, 100 degrees C), stiring time (10, 20, 30 min) and the proportion of pieces and wheat bran (100: 5, 100: 10, 100: 15) were evaluated by orthogonal method. The content of allantoin in Rhizoma Dioscoreae was determine by HPLC method. RESULT: The amount of wheat bran could affect the content of allation significantly, and stiring temperature and stiring time almost had no effect on content of allantoin. The processing technics was tested by industrial produce, according to 11 batches from 4 growing regions. The result showed that the quality of industrial product was stable. CONCLUSION: That the amount of wheat bran can affect the quality of Rhizoma Dioscoreae greatly. The determined technics is simple and suitable for prepared slice of Rhizoma Dioscoreae industrival manufacture.