Design, synthesis and evaluation of the anti-breast cancer activity of 1,3-oxazolo[4,5-d]pyrimidine and 1,3-oxazolo[5,4-d]pyrimidine derivatives.

A series of 1,3-oxazolo[4,5-d]pyrimidine and 1,3-oxazolo[5,4-d]pyrimidine derivatives were synthesized and functionalized in this study. The obtained compounds were tested against breast cancer cell lines of the NCI subpanel, followed by further analysis using the COMPARE algorithm from the Therapeutics Development Program, NCI. All synthesized derivatives displayed activity against most cell lines in the range of micromolar concentrations in terms of all parameters studied. Oxazolopyrimidine 5 exhibited the highest antitumor activity. A standard COMPARE analysis of the compounds showed that the vectors of the cytotoxic activity of derivatives 10 and 11 displayed a close to very high correlation with tamoxifen, and oxazolopyrimidine 13 displayed a very high correlation with the same drug. Five derivatives (2, 4, 6, 11 and 13) showed a high correlation with aclacinomycin A in the TGI vector. At the same time, compound 1 effectively suppressed ADK in cultured MDA-MB 231 cell lines, indicating that ADK is one of its targets through which it exerts anticancer properties. Based on molecular docking results, the possible binding mode of oxazolopyrimidine 1 to ADK has been suggested.

Adenosine-A2A Receptor Signaling Plays a Crucial Role in Sudden Unexpected Death in Epilepsy.

Adenosinergic activities are suggested to participate in SUDEP pathophysiology; this study aimed to evaluate the adenosine hypothesis of SUDEP and specifically the role of adenosine A2A receptor (A2AR) in the development of a SUDEP mouse model with relevant clinical features. Using a combined paradigm of intrahippocampal and intraperitoneal administration of kainic acid (KA), we developed a boosted-KA model of SUDEP in genetically modified adenosine kinase (ADK) knockdown (Adk+/-) mice, which has reduced ADK in the brain. Seizure activity was monitored using video-EEG methods, and in vivo recording of local field potential (LFP) was used to evaluate neuronal activity within the nucleus tractus solitarius (NTS). Our boosted-KA model of SUDEP was characterized by a delayed, postictal sudden death in epileptic mice. We demonstrated a higher incidence of SUDEP in Adk+/- mice (34.8%) vs. WTs (8.0%), and the ADK inhibitor, 5-Iodotubercidin, further increased SUDEP in Adk+/- mice (46.7%). We revealed that the NTS level of ADK was significantly increased in epileptic WTs, but not in epileptic Adk+/- mutants, while the A2AR level in NTS was increased in epileptic (WT and Adk+/-) mice vs. non-epileptic controls. The A2AR antagonist, SCH58261, significantly reduced SUDEP events in Adk+/- mice. LFP data showed that SCH58261 partially restored KA injection-induced suppression of gamma oscillation in the NTS of epileptic WT mice, whereas SCH58261 increased theta and beta oscillations in Adk+/- mutants after KA injection, albeit with no change in gamma oscillations. These LFP findings suggest that SCH58261 and KA induced changes in local neuronal activities in the NTS of epileptic mice. We revealed a crucial role for NTS A2AR in SUDEP pathophysiology suggesting A2AR as a potential therapeutic target for SUDEP risk prevention.

Adenosine kinase inhibition promotes proliferation of neural stem cells after traumatic brain injury.

Traumatic brain injury (TBI) is a major public health concern and remains a leading cause of disability and socio-economic burden. To date, there is no proven therapy that promotes brain repair following an injury to the brain. In this study, we explored the role of an isoform of adenosine kinase expressed in the cell nucleus (ADK-L) as a potential regulator of neural stem cell proliferation in the brain. The rationale for this hypothesis is based on coordinated expression changes of ADK-L during foetal and postnatal murine and human brain development indicating a role in the regulation of cell proliferation and plasticity in the brain. We first tested whether the genetic disruption of ADK-L would increase neural stem cell proliferation after TBI. Three days after TBI, modelled by a controlled cortical impact, transgenic mice, which lack ADK-L (ADKΔneuron) in the dentate gyrus (DG) showed a significant increase in neural stem cell proliferation as evidenced by significant increases in doublecortin and Ki67-positive cells, whereas animals with transgenic overexpression of ADK-L in dorsal forebrain neurons (ADK-Ltg) showed an opposite effect of attenuated neural stem cell proliferation. Next, we translated those findings into a pharmacological approach to augment neural stem cell proliferation in the injured brain. Wild-type C57BL/6 mice were treated with the small molecule adenosine kinase inhibitor 5-iodotubercidin for 3 days after the induction of TBI. We demonstrate significantly enhanced neural stem cell proliferation in the DG of 5-iodotubercidin-treated mice compared to vehicle-treated injured animals. To rule out the possibility that blockade of ADK-L has any effects in non-injured animals, we quantified baseline neural stem cell proliferation in ADKΔneuron mice, which was not altered, whereas baseline neural stem cell proliferation in ADK-Ltg mice was enhanced. Together these findings demonstrate a novel function of ADK-L involved in the regulation of neural stem cell proliferation after TBI.

Sarcosine Suppresses Epileptogenesis in Rats With Effects on Hippocampal DNA Methylation.

Epileptogenesis is a common consequence of brain insults, however, the prevention or delay of the epileptogenic process remains an important unmet medical challenge. Overexpression of glycine transporter 1 (GlyT1) is proposed as a pathological hallmark in the hippocampus of patients with temporal lobe epilepsy (TLE), and we previously demonstrated in rodent epilepsy models that augmentation of glycine suppressed chronic seizures and altered acute seizure thresholds. In the present study we evaluated the effect of the GlyT1 inhibitor, sarcosine (aka N-methylglycine), on epileptogenesis and also investigated possible mechanisms. We developed a modified rapid kindling model of epileptogenesis in rats combined with seizure score monitoring to evaluate the antiepileptogenic effect of sarcosine. We used immunohistochemistry and Western blot analysis for the evaluation of GlyT1 expression and epigenetic changes of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in the epileptogenic hippocampi of rats, and further evaluated expression changes in enzymes involved in the regulation of DNA methylation, ten-eleven translocation methylcytosine dioxygenase 1 (TET1), DNA-methyltransferase 1 (DNMT1), and DNMT3a. Our results demonstrated: (i) experimental evidence that sarcosine (3 g/kg, i.p. daily) suppressed kindling epileptogenesis in rats; (ii) the sarcosine-induced antiepileptogenic effect was accompanied by a suppressed hippocampal GlyT1 expression as well as a reduction of hippocampal 5mC levels and a corresponding increase in 5hmC; and (iii) sarcosine treatment caused differential expression changes of TET1 and DNMTs. Together, these findings suggest that sarcosine has unprecedented disease-modifying properties in a kindling model of epileptogenesis in rats, which was associated with altered hippocampal DNA methylation. Thus, manipulation of the glycine system is a potential therapeutic approach to attenuate the development of epilepsy.