Search

Abstract INTRODUCTION: Isocitrate dehydrogenase 1 and 2 mutations (mIDH1/2) occur in >70% of low-grade gliomas and secondary glioblastomas, and lead to genetic and epigenetic dysregulation, promoting tumorigenesis. AG-881 is an oral, potent, brain-penetrant inhibitor of mIDH1/2 under phase 1 clinical evaluation in gliomas and other solid tumors. Here we present clinical data from the glioma population. METHODS Patients with recurrent/progressive mIDH1/2 glioma received AG-881 daily in continuous 28-day cycles. A Bayesian model was used for dose escalation. Dose-limiting toxicity (DLT) definition: Grade 3 AG-881-related adverse event (AE) in Cycle 1 or by sponsor designation. Blood samples were collected for pharmacokinetic (PK)/pharmacodynamic (PD) evaluations. MRI response every 8 weeks by RANO and RANO-LGG criteria. RESULTS As of 28Mar2018, 52 patients with glioma had received AG-881 and 17 (32.7%) remained on treatment. Grade 2/3 = 90.4%; median age = 42.5 years; IDH1/2: 48/3; median no. prior therapies = 2 (range 1–6). Five initial dose levels tested: 25mg (n=6), 50mg (n=5), 100mg (n=10), 200mg (n=14), and 300mg (n=5). To confirm safety and PK, a 10mg dose level was tested (n=6) and 6 additional patients enrolled in the 50mg cohort. Common (>20%) AEs across glioma patients regardless of attribution: ALT increased (44.2%), AST increased (38.5%), headache (34.6%), fatigue (30.8%), nausea (26.9%), seizure (21.2%). Five patients experienced DLTs at 100mg: Grade 2 ALT/AST that resolved to Grade 1 with dose modification (n=4) or discontinuation (n=1). Among the evaluable glioma population: 2% minor response, 75% stable disease, 21% progressive disease, and 2% missing as best overall response. CONCLUSION: Maximum tolerated dose/recommended phase 2 dose was not reached by Bayesian model; clinical team recommendation was to proceed with doses

Byline: Huansheng Xu (a)(c), Antonella Viola (b), Zhen Zhang (c), Claudia P. Gerken (d), Elizabeth A. Lindsay-Illingworth (a)(b), Antonio Baldini (a)(b)(c) Keywords: Tbx1; Inner ear; Neurogenesis; Cell fate specification; Dll1; Notch1; Ngn1; Periotic mesenchyme; Otic epithelium Abstract: The T-box transcription factor Tbx1 is required for inner ear morphogenesis. Tbx1 null mutants have a small otocyst that fails to grow and remodel and does not give rise to the vestibular and cochlear apparata. Here we show that Tbx1 expression-driven cell tracing identifies a population of otic epithelial cells that contributes to most of the otocyst. Tbx1 is essential for the contribution of this population to the inner ear. Ablation of Tbx1 after this cell population has established itself in the otocyst, restores marker expression lost in germ line mutants, but causes severe reduction in mitotic activity, cell autonomously. Furthermore, timed cell fate mapping demonstrates that loss of Tbx1 switches the fate of some members of the Tbx1-dependent cell population, from non-neurogenic to neurogenic, an event associated with activation of the Delta-Notch pathway. Finally, tissue-specific ablation of Tbx1 demonstrates that, while the abovementioned phenotypic abnormalities are due to loss of epithelial expression of Tbx1, cochlear morphogenesis requires mesodermal Tbx1 expression. We conclude that the main functions of Tbx1 in the inner ear are to control, cell-autonomously, contribution, size and fate of a large population of otic epithelial cells, and, cell non-autonomously, cochlear morphogenesis. Author Affiliation: (a) Institute of Biosciences and Technologies, Texas A&M University System, 2121 W. Holcombe, Room 820C, TX, USA (b) Department of Biochemistry, University Federico II, and Tigem, Via P. Castellino Naples, Italy (c) Program in Cardiovascular Sciences, Baylor College of Medicine, Houston, TX 77030, USA (d) Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA Article History: Received 21 June 2006; Revised 30 September 2006; Accepted 3 October 2006

Ivosidenib, a small‐molecule inhibitor of mutant isocitrate dehydrogenase 1, is primarily cleared by hepatic metabolism. This open‐label study investigated the impact of hepatic impairment on ivosidenib pharmacokinetics (ClinicalTrials.gov: NCT03282513). Otherwise healthy participants with mild (n = 9) or moderate (n = 8) hepatic impairment (Child‐Pugh score) and matched participants with normal hepatic function (n = 16) received 1 oral dose of 500‐mg ivosidenib. Mild hepatic impairment had a negligible effect on total ivosidenib plasma exposure, with geometric mean ratios (90% confidence interval [CI]) of 0.933 (0.715‐1.22) for maximum concentration (Cmax) and 0.847 (0.624‐1.15) for area under the plasma concentration–time curve (AUC) in participants with mild hepatic impairment versus matched controls. Moderate hepatic impairment reduced total ivosidenib exposure by 28% to 44%, with geometric mean ratios (90%CI) of 0.565 (0.419‐0.763) for Cmax and 0.716 (0.479‐1.07) for AUC, although the 90%CI for AUC included 1.00. The ivosidenib unbound fraction was concentration dependent and higher in participants with mild/moderate hepatic impairment compared with matched controls. There was no apparent trend to increasing unbound Cmax with increased hepatic impairment severity. A single 500‐mg ivosidenib dose was well tolerated, with no serious or severe adverse events and no adverse events leading to discontinuation. We conclude that mild/moderate hepatic impairment did not lead to clinically relevant changes in ivosidenib exposure following a single 500‐mg dose. [ABSTRACT FROM AUTHOR]

Cardiomyocytes derived from pluripotent stem cells can be applied in drug testing, disease modeling and cell-based therapy. However, without procardiogenic growth factors, the efficiency of cardiomyogenesis from pluripotent stem cells is usually low and the resulting cardiomyocyte population is heterogeneous. Here, we demonstrate that induced pluripotent stem cells (iPSCs) can be derived from murine ventricular myocytes (VMs), and consistent with other reports of iPSCs derived from various somatic cell types, VM-derived iPSCs (ViPSCs) exhibit a markedly higher propensity to spontaneously differentiate into beating cardiomyocytes as compared to genetically matched embryonic stem cells (ESCs) or iPSCs derived from tail-tip fibroblasts. Strikingly, the majority of ViPSC-derived cardiomyocytes display a ventricular phenotype. The enhanced ventricular myogenesis in ViPSCs is mediated via increased numbers of cardiovascular progenitors at early stages of differentiation. In order to investigate the mechanism of enhanced ventricular myogenesis from ViPSCs, we performed global gene expression and DNA methylation analysis, which revealed a distinct epigenetic signature that may be involved in specifying the VM fate in pluripotent stem cells. [ABSTRACT FROM AUTHOR]

Background and Aims Saccharomyces boulardii (Sb) can protect against intestinal injury and tumor formation, but how this probiotic yeast controls protective mucosal host responses is unclear. Angiogenesis is an integral process of inflammatory responses in inflammatory bowel diseases (IBD) and required for mucosal remodeling during restitution. The aim of this study was to determine whether Sb alters VEGFR (vascular endothelial growth factor receptor) signaling, a central regulator of angiogenesis. Methods: HUVEC were used to examine the effects of Sb on signaling and on capillary tube formation (using the ECMatrix™ system). The effects of Sb on VEGF-mediated angiogenesis were examined in vivo using an adenovirus expressing VEGF-A(164) in the ears of adult nude mice (NuNu). The effects of Sb on blood vessel volume branching and density in DSS-induced colitis was quantified using VESsel GENeration (VESGEN) software. Results: 1) Sb treatment attenuated weight-loss (p<0.01) and histological damage (p<0.01) in DSS colitis. VESGEN analysis of angiogenesis showed significantly increased blood vessel density and volume in DSS-treated mice compared to control. Sb treatment significantly reduced the neo-vascularization associated with acute DSS colitis and accelerated mucosal recovery restoration of the lamina propria capillary network to a normal morphology. 2) Sb inhibited VEGF-induced angiogenesis in vivo in the mouse ear model. 3) Sb also significantly inhibited angiogenesis in vitro in the capillary tube assay in a dose-dependent manner (p<0.01). 4) In HUVEC, Sb reduced basal VEGFR-2 phosphorylation, VEGFR-2 phosphorylation in response to VEGF as well as activation of the downstream kinases PLCγ and Erk1/2. Conclusions: Our findings indicate that the probiotic yeast S boulardii can modulate angiogenesis to limit intestinal inflammation and promote mucosal tissue repair by regulating VEGFR signaling.

During embryonic life, the initially paired pharyngeal arch arteries (PAAs) follow a precisely orchestrated program of persistence and regression that leads to the formation of the mature aortic arch and great vessels. When this program fails, specific cardiovascular defects arise that may be life threatening or mild, according to the identity of the affected artery. Fourth PAA-derived cardiovascular defects occur commonly in DiGeorge syndrome and velocardiofacial syndrome (22q11DS), and in Tbx1(+/-) mice that model the 22q11DS cardiovascular phenotype. Tbx1 is expressed in pharyngeal mesoderm, endoderm and ectoderm, and, in addition, we show that it is expressed in precursors of the endothelial cells that line the PAAs, thus expanding the number of tissues in which Tbx1 is potentially required for fourth PAA development. In this study, we have used cell fate mapping and tissue-specific gene deletion, driven by six different Cre lines, to explore Tbx1 gene-dosage requirements in the embryonic pharynx for fourth PAA development. Through this approach, we have resolved the spatial requirements for Tbx1 in this process, and we show pharyngeal epithelia to be a critical tissue. We also thereby demonstrate conclusively that the role of Tbx1 in fourth PAA development is cell non-autonomous.

Dysmorphogenesis of the cardiac outflow tract (OFT) causes many congenital heart defects, including those associated with DiGeorge syndrome. Genetic manipulation in the mouse and mutational analysis in patients have shown that Tbx1, a T-box transcription factor, has a key role in the pathogenesis of this syndrome. Here, we have dissected Tbx1 function during OFT development using genetically modified mice and tissue-specific deletion, and have defined a dual role for this protein in OFT morphogenesis. We show that Tbx1 regulates cell contribution to the OFT by supporting cell proliferation in the secondary heart field, a source of cells fated to the OFT. This process might be regulated in part by Fgf10, which we show for the first time to be a direct target of Tbx1 in vitro. We also show that Tbx1 expression is required in cells expressing Nkx2.5 for the formation of the aorto-pulmonary septum, which divides the aorta from the main pulmonary artery. These results explain why aortic arch patterning defects and OFT defects can occur independently in individuals with DiGeorge syndrome. Furthermore, our data link, for the first time, the function of the secondary heart field to congenital heart disease.