A High-Content Small Molecule Screen Identifies Sensitivity of Glioblastoma Stem Cells to Inhibition of Polo-Like Kinase 1

Glioblastoma multiforme (GBM) is the most common primary brain cancer in adults and there are few effective treatments. GBMs contain cells with molecular and cellular characteristics of neural stem cells that drive tumour growth. Here we compare responses of human glioblastoma-derived neural stem (GNS) cells and genetically normal neural stem (NS) cells to a panel of 160 small molecule kinase inhibitors. We used live-cell imaging and high content image analysis tools and identified JNJ-10198409 (J101) as an agent that induces mitotic arrest at prometaphase in GNS cells but not NS cells. Antibody microarrays and kinase profiling suggested that J101 responses are triggered by suppression of the active phosphorylated form of polo-like kinase 1 (Plk1) (phospho T210), with resultant spindle defects and arrest at prometaphase. We found that potent and specific Plk1 inhibitors already in clinical development (BI 2536, BI 6727 and GSK 461364) phenocopied J101 and were selective against GNS cells. Using a porcine brain endothelial cell blood-brain barrier model we also observed that these compounds exhibited greater blood-brain barrier permeability in vitro than J101. Our analysis of mouse mutant NS cells (INK4a/ARF^−/−, or p53^−/−), as well as the acute genetic deletion of p53 from a conditional p53 floxed NS cell line, suggests that the sensitivity of GNS cells to BI 2536 or J101 may be explained by the lack of a p53-mediated compensatory pathway. Together these data indicate that GBM stem cells are acutely susceptible to proliferative disruption by Plk1 inhibitors and that such agents may have immediate therapeutic value.     

Effect of retinyl acetate on transglutaminase 2 activity in carcinogen treated rat liver

Transglutaminase 2 (TG2) has been implicated in wound healing, cellular differentiation, apoptosis and cell survival. TG2 activity increases following acute and chronic liver injury; however, the role of TG2 in tumors, is controversial. TG2 is a retinoid-inducible enzyme. We investigated the effects of retinyl acetate (RA) on the activity and levels of TG2 during the initiation and promotion stages of liver cancer. p-Dimethylaminoazobenzene (p-DAB) was used as initiator and 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) was used as promoter in our model of carcinogenesis. Rats were divided into four groups of 24: control, corn oil control, p-DAB + TCDD, and p-DAB + TCDD + RA. Six rats from each group were sacrificed at days 30, 60, 90 and 120. TG2 activity decreased in the p-DAB + TCDD treated group, but TG2 immunostaining scores did not change by days 90 and 120. Neither TG2 enzyme activity nor the immunostaining score of TG2 protein changed in the tissues of the p-DAB + TCDD + RA group by days 90 and 120. TG2 activity was not be ameliorated by RA during the initiation or promotion stages of carcinogen induced liver cancer.     

Vers une approche physiopathologique des troubles de l’éjaculation

Seminal emission and sperm expulsion are under the control of both the sympathetic and parasympathetic outflows and also of the somatic innervation conveyed by the pudendal nerve. The 2 phases of ejaculation are reflexive with the reflexes handled at the thoraco-lumbar and sacral levels of the spinal cord. Such a spinal organization remains widely unknown. The role of various peripheral neurotransmitters has been evidenced including norepinephrine and acetylcholine and also peptidergic, purinergic i.e. ATP and nitric oxide. Stimulation of the seminal tract afferents play a crucial in the onset of ejaculatory mechanisms. Except for the dorsal nerve of the penis, there is a lack of information concerning these afferents. Several supraspinal centers i.e. hypothalamus, medial amygdala, pons and nucleus paragigantocellularis exert descending and ascending inhibitory and excitatory influences on spinal nuclei controlling emission and expulsion of sperm. Central neurotransmission responsible for this supraspinal control could involve serotonin, oxytocin and norepinephrine. In the light of the available anatomical and neurophysiological data, pathophysiological aspects of ejaculatory disorders are futher discussed. Premature ejaculation could be related to a periheral and central hypersentivity. Most of the other ejaculation abnormalities are likely mainly related to an impairment of the central mechanisms.     

Molecularly imprinted hydrophilic polymer sorbents for selective sorption of erythromycin

New hydrophilic polymer sorbents comprising reactionary sites which are complementary to a molecule of antibiotic erythromycin were synthesized by the method of molecular imprinting. A series of similar sorbents without reactionary sites was used for comparison of sorption characteristics. Sorption of erythromycin on both types of polymer sorbents synthesized was studied in a wide range of pH and ionic strength. Selectivity of erythromycin sorption on molecularly imprinted cross-linked polymers was shown to depend on the specific interaction of target molecule with polymer matrix. This type of sorbent is perspective for the development of antibiotic purification directly from a culture medium Saccharopolyspora erythreus.     

Development of Tolerance for Copper in Cyanobacteria Repeatedly Exposed to Its Toxic Effect

Experiments on cyanobacterial cultures showed that initial exposure to copper at concentrations of 0.01–0.05 mg/l not only has a direct toxic effect, but also significantly modifies the copper tolerance of cyanobacteria for repeated exposure. The response to repeated exposure and the mechanism of tolerance depend on the strength of the initial effect of copper and the extent of heterogeneity of the initial cyanobacterial population.     

Cytogenetic anomalies and causes for their occurrence in somatic cells

Different types of cytogenetic anomalies used in classical cytogenetics for estimating the level of damage to the chromosome apparatus are considered. Possible causes for the occurrence of different types of cytogenetic anomalies as well as the range of methods of micronucleus testing are discussed. It is shown that different levels of organization of genetic material (nucleotide, chromosome, or suprachromosome material) have an effect on processes involved in realization of a defect in the nucleotide sequence into a cytogenetic anomaly.     

Development of the visual system of anchovy larvae,Engraulis anchoita: A microanatomical description

During the early ontogeny of fish larvae, the accurate development of the visual system plays a key role, because it is involved in locating food, orientation, selection of favorable habitat, and evasion of predators. The structure of the eye of the fish is typical of vertebrates, with some modifications related to the aquatic environment. In the present work, we describe the development of the larval eye of Engraulis anchoita for the first time. Larvae were collected at the Permanent Station of Environmental Studies (EPEA) in coastal waters of the Southwestern Atlantic Ocean during research cruises in 2015 and 2016. We describe the histology of the retina layers, determine the beginning of the functionality of the eye, and discuss a possible synchronization with the development of the digestive tract. This study provides information about the biology of E. anchoita, the most abundant fish species in the southwestern Atlantic Ocean. Also, recent studies have shown responses of the retina and other tissues to the increase in environmental acidity. Therefore, results of this study are also discussed with respect to the possible effect of acidification on the larvae of this species. The continuity of the time series developed at the EPEA will allow monitoring the effect of long-term environmental and biological variables on the early ontogeny of anchovy in the context of climate change. The high commercial fishing potential of E. anchoita due to its high abundance, as well as its essential role in the trophic web of other commercially valuable fishing resources of Argentina, reinforce the need to continue deepening knowledge about this species. Research highlights:

• Eyes of Engraulis anchoita larvae are functional from early larval stages.
• At hatching, the retina is formed by only few layers from which the other layers differentiates during ontogeny.
• Focal distance increases with larval growth.