BPR1K653, a novel Aurora kinase inhibitor, exhibits potent anti-proliferative activity in MDR1 (P-gp170)-mediated multidrug-resistant cancer cells

Background

Over-expression of Aurora kinases promotes the tumorigenesis of cells. The aim of this study was to determine the preclinical profile of a novel pan-Aurora kinase inhibitor, BPR1K653, as a candidate for anti-cancer therapy. Since expression of the drug efflux pump, MDR1, reduces the effectiveness of various chemotherapeutic compounds in human cancers, this study also aimed to determine whether the potency of BPR1K653 could be affected by the expression of MDR1 in cancer cells.

Principal Findings

BPR1K653 specifically inhibited the activity of Aurora-A and Aurora-B kinase at low nano-molar concentrations in vitro. Anti-proliferative activity of BPR1K653 was evaluated in various human cancer cell lines. Results of the clonogenic assay showed that BPR1K653 was potent in targeting a variety of cancer cell lines regardless of the tissue origin, p53 status, or expression of MDR1. At the cellular level, BPR1K653 induced endo-replication and subsequent apoptosis in both MDR1-negative and MDR1-positive cancer cells. Importantly, it showed potent activity against the growth of xenograft tumors of the human cervical carcinoma KB and KB-derived MDR1-positive KB-VIN10 cells in nude mice. Finally, BPR1K653 also exhibited favorable pharmacokinetic properties in rats.

Conclusions and Significance

BPR1K653 is a novel potent anti-cancer compound, and its potency is not affected by the expression of the multiple drug resistant protein, MDR1, in cancer cells. Therefore, BPR1K653 is a promising anti-cancer compound that has potential for the management of various malignancies, particularly for patients with MDR1-related drug resistance after prolonged chemotherapeutic treatments.     

Dormancy and the influence of photoperiod and temperature on sexual maturity in Nicrophorus nepalensis (Coleoptera: Silphidae)

Abstract Carrion beetles (Nicrophorus spp.) use small vertebrate carcasses for food and reproduction. Their ecology and behaviors are highly affected by the availability of carcasses and the surrounding environmental conditions. Our results revealed that in subtropical Fushan, northern Taiwan, N. nepalensis was mainly active in spring (February to May), and could also be found in autumn (October and November); but there was no capture record in summer (June to September) and winter (December and January). A laboratory temperature tolerance study indicated that N. nepalensis adults become inactive at temperatures above 26°C, and had the highest mortality when the temperature was raised from 27°C to 28°C. Furthermore, N. nepalensis became sexually mature at 20°C, depending on the photoperiod: the longer the day, the lower the percentage of sexually mature 2‐week‐old females after emergence. In another experiment, N. nepalensis virgins were paired under three possible conditions at Fushan. At 15°C and 20°C, if carcasses were presented to the pairs within 3 days after emergence, all laid eggs in the second week after emergence. If carcasses were presented 1 week after emergence, most began to reproduce at 20°C with 12.5 h of daylight. However, at 15°C with 11 h of daylight, the carrion beetles hibernated first, and reproduced in the ninth week after emergence. At 25°C with 14 h of daylight, carrion beetles did not bury the mouse carcasses, the females did not lay eggs, and the adult lifespan was only one‐third of that at 20°C. This study revealed that both photoperiod and temperature influence the time needed to reach the sexual maturity of N. nepalensis; and also implied that the narrow temperature tolerance range and dormancy behavior of carrion beetles are highly regulated by those environmental factors.     

Antifibrotic effects of <Emphasis Type="Italic">Salvia miltiorrhiza </Emphasis>on dimethylnitrosamine-intoxicated rats

Excessive oxidative stress is implicated in hepatic fibrogenesis. Extracts of Salvia miltiorrhiza (Sm) have been shown to protect cells against oxidative stress. In this study we investigated the in vitro and in vivo effects of Sm on hepatic fibrosis. A cell line of rat hepatic stellate cells (HSC-T6) was stimulated with transforming growth factor-1 (TGF-1). The inhibitory effects of Sm (50~400 g/ml) on TGF-1-induced -smooth muscle actin (-SMA) secretion and the mRNA expressions of fibrosis-related genes, including -SMA, connective tissue growth factor (CTGF), and tissue inhibitor of metalloproteinase-1 (TIMP-1), were assessed. Fibrosis was induced by dimethylnitrosamine (DMN) administration in rats. DMN-treated rats were randomly assigned to 1 of 4 groups: saline, Sm (20 mg/kg), Sm (100 mg/kg), or silymarin (100 mg/kg), each given by gavage twice daily for 5 weeks starting from the onset of DMN administration. Sm (200 and 400 g/ml) significantly inhibited TGF-1-stimulated -SMA secretion and the mRNA expressions of -SMA, CTGF, and TIMP-1 in HSC-T6 cells. Fibrosis scores of livers from DMN-treated rats with either a low (1.8 ± 0.2) or high (1.8 ± 0.1) dose of Sm, or silymarin (1.4 ± 0.2) were significantly reduced in comparison with DMN-treated rats receiving saline (3.1 ± 0.1). Hepatic collagen contents were also significantly reduced by either Sm or silymarin treatment. The mRNA expression levels of -SMA, TGF-1, and procollagen I were all attenuated in Sm- and silymarin-treated rats. Moreover, levels of plasma aspartate transaminase activities were reduced by Sm and silymarin treatment. In conclusion, our results show that Sm exerted antifibrotic effects in both HSC-T6 cells and in rats with DMN-induced fibrosis.     

In vitro cytotoxic activity of isolated acridones alkaloids from Zanthoxylum leprieurii Guill. et Perr

Chemical investigation of the roots and fruits of Zanthoxylum leprieurii Guill. et Perr. led to the isolation of three new alkaloids including two acridone derivatives, 3-hydroxy-1,4-dimethoxy-10-methyl-9-acridone (2) and 3-hydroxy-1,2-dimethoxy-10-methyl-9-acridone (3) named helebelicine A and B, respectively, and one secobenzo[c]phenantridine, 10-O-demethyl-12-O-methylarnottianamide (10), together with thirteen other compounds. The structures of compounds 2, 3 and 10 as well as those of the known compounds were elucidated by using spectroscopic methods and by comparison with reported data. The brine-shrimp (artemia salina) lethality bioassay of the chloroform extract of the fruits showed modest cytotoxicity with LD₅₀ at 13.1 μg/mL. Isolated compounds 1, 4–6 were found to be moderately active against lung carcinoma cells (A549), colorectal adenocarcinoma cells (DLD-1) and normal cells (WS1) with IC₅₀ values ranging from 27 to 77 μM. In contrast to the positive control etoposide used, the cytotoxicity of the most active compound 4 was found to be selective against cancer cells in comparison to normal cells WS1 with IC₅₀ of 51 ± 8 μM and 4.3 ± 0.4 μM, respectively.     

Can Otolith Microchemistry Reveal Whether the Blind Cave Gudgeon, Milyeringa veritas (Eleotridae), is Diadromous within a Subterranean Estuary?

Synopsis The blind cavefish, Milyeringa veritas, inhabits an anchialine system, effectively a groundwater estuary, in which salinity varies between fresh and seawater at different locations and depths. Owing to the inaccessible habitat and the threatened status of the cavefish it is hard to obtain the biological information needed for their management. This paper explores the utility of otolith Sr:Ca ratio in elucidating cavefish biology. The mean Sr:Ca ratio of the water inhabited by the cavefish is correlated with both the TDS (total dissolved solids) of the habitat and with the Sr:Ca ratio of the sagittal otolith of the cavefish inhabiting that site. Mean values of Sr:Ca in otoliths suggest some cavefish inhabit sea or brackish waters while others remain in freshwater. Some individuals appear to move between waters of very different TDS at various stages but there is no consistency in the direction or apparent TDS range of the water bodies inhabited which indicates that the cavefish utilise the different water bodies opportunistically. Residual analyses indicate clear and routine changes in the TDS of the water occupied at various phases of growth, irrespective of the TDS at which the cavefish were sampled. Annular markings are present in some otoliths but they cannot be related to likely periodicities in the subterranean environment.     

Effect of diuretic use on 30-day postdialysis mortality in critically ill patients receiving acute dialysis

Background

The impact of diuretic usage and dosage on the mortality of critically ill patients with acute kidney injury is still unclear.

Methods and Results

In this prospective, multicenter, observational study, 572 patients with postsurgical acute kidney injury receiving hemodialysis were recruited and followed daily. Thirty-day postdialysis mortality was analyzed using Cox''s proportional hazards model with time-dependent covariates. The mean age of the 572 patients was 60.8±16.6 years. Patients with lower serum creatinine (p = 0.031) and blood lactate (p = 0.033) at ICU admission, lower predialysis urine output (p = 0.001) and PaO₂/FiO₂ (p = 0.039), as well as diabetes (p = 0.037) and heart failure (p = 0.049) were more likely to receive diuretics. A total of 280 (49.0%) patients died within 30 days after acute dialysis initiation. The analysis of 30-day postdialysis mortality by fitting propensity score-adjusted Cox''s proportional hazards models with time-dependent covariates showed that higher 3-day accumulated diuretic doses after dialysis initiation (HR = 1.449, p = 0.021) could increase the hazard rate of death. Moreover, higher time-varying 3-day accumulative diuretic doses were associated with hypotension (p<0.001) and less intense hemodialysis (p<0.001) during the acute dialysis period.

Background and Significance

Higher time-varying 3-day accumulative diuretic dose predicts mortality in postsurgical critically ill patients requiring acute dialysis. Higher diuretic doses are associated with hypotension and a lower intensity of dialysis. Caution should be employed before loop diuretics are administered to postsurgical patients during the acute dialysis period.     

Juvenile hormone connects larval nutrition with target of rapamycin signaling in the mosquito Aedes aegypti

Anautogenous mosquitoes require blood meals to promote egg development. If adequate nutrients are not obtained during larval development, the resulting "small" sized adult mosquitoes require multiple blood meals for egg development; markedly increasing host-vector contacts and the likelihood of disease transmission. Nutrient-sensitive target of rapamycin (TOR) signaling is a key signaling pathway that links elevated hemolymph amino acid levels derived from the blood meal to the expression of yolk protein precursors in the fat body. Here we report that the blood-meal-induced activation of the TOR-signaling pathway and subsequent egg maturation depends on the accumulation of adequate nutritional reserves during larval development. We have established well-nourished, "standard" mosquitoes and malnourished, "small" mosquitoes as models to address this nutrient sensitive pathway. This regulatory mechanism involves juvenile hormone (JH), which acts as a mediator of fat body competence, permitting the response to amino acids derived from the blood meal. We demonstrate that treatment with JH results in recovery of the TOR molecular machinery, Aedes aegypti cationic amino acid transporter 2 (AaiCAT2), TOR, and S6 kinase (S6K), in fat bodies of small mosquitoes, enabling them to complete their first gonotrophic cycle after a single blood meal. These findings establish a direct link between nutrient reserves and the establishment of TOR signaling in mosquitoes.     

Diabetes reduces aortic endothelial gap junctions in ApoE-deficient mice: simvastatin exacerbates the reduction.

We examined the endothelial gap junctions in diabetic hyperlipidemic mice. Male apolipoprotein E (apoE)-deficient mice were made diabetic by streptozotocin. Three weeks later, the animals were treated with simvastatin for 2 weeks. The expression of aortic gap junctions in the non-diabetic (n=10), untreated diabetic (n=10), and simvastatin-treated diabetic animals (n=6) was analyzed. There was a >4-fold increase in serum cholesterol level and >50% increase in plaque areas in the diabetic mice, regardless of simvastatin treatment. Western blotting of aortae showed reduced expression of connexin37 (Cx37) and Cx40 in the diabetic mice, which were further decreased in the simvastatin-treated diabetic mice. Immunoconfocal microscopy showed that endothelial gap junctions made of Cx37 and Cx40 were both reduced in the untreated diabetic mice compared with the non-diabetic mice (decrease: Cx37, 41%; Cx40, 42%; both p<0.01). The reduction was greater in the simvastatin-treated mice (decrease in treated diabetic vs non-diabetic: Cx37, 61%; Cx40, 79%; both p<0.01; decrease in treated diabetic vs untreated diabetic: Cx37, 34%; Cx40, 63%; both p<0.01). Cx37 and Cx40 were decreased in the endothelium of plaque surface. Cx43 appeared in the medial layer and inner layer of the intima. All three connexins were rarely expressed in monocytes/macrophages inside the plaques. In conclusion, in apoE-deficient mice, streptozotocin-induced diabetes is associated with downregulation of endothelial Cx37 and Cx40 gap junctions. Short-term treatment with simvastatin exacerbates the downregulation.     

Amplification of single bulb mites by nested PCR: Species-specific primers to detect Rhizoglyphus robini and R. setosus (Acari: Acaridae)

A major problem of using molecular amplicons for DNA amplification in mite systematics is that sufficient template cannot always be acquired from an individual mite. To solve this problem, we developed a nested PCR for DNA amplification of single Rhizoglyphus robini and R. setosus bulb mites. A dilution up to 10⁵ of the DNA from a single egg, larva, nymph or adult contained enough templates for amplification of the target ribosomal region. However, the use of specific primers in the second PCR is necessary to reduce the generation of non-target DNAs from symbiotic organisms. Identification of bulb mites collected from seven sampling locations in Taiwan or of bulb mites that were used in simulated experiments in the presence of host plant tissues was unambiguous with specific PCR primers.     

Synthesis and antitumor activity of bis(hydroxymethyl)propionate analogs of pterostilbene in cisplatin-resistant human oral cancer cells

The aim of this study was to develop a new drug substance with low toxicity and effective inhibitory activity against cisplatin-resistant oral cancer. The naturally produced pterostilbene was selected as the lead compound for design and synthesis of a series of bis(hydroxymethyl)propionate-based prodrugs. All derivatives were screened for antiproliferative effects against the cisplatin-resistant oral squamous (CAR) cell line and the results indicated that several compounds demonstrated superior inhibitory activity compared with pterostilbene and resveratrol. Among them, the most promising compound, 12, was evaluated for in vivo antitumor activity in a CAR xenograft nude mouse model. Obvious antitumor activity was observed at the lowest oral dose (25?mg/kg/day). Increasing the dose of 12 to 100?mg/kg/day reduced the tumor size to 22% of the control group. Based on these findings as well as the extremely low toxicity seen in the in vivo studies, we believe that compound 12 could serve as a new lead for further development.