CeeTox analyses using a rat hepatoma cell line (H4IIE) resulted in estimated C-Tox value (i.e., CA3 datasheet sustained concentration expected to produce toxicity in a rat 14-day repeat dose study) of 42 mu M for CNB-001 compared with >300 mu M for both NXY-059 and Radicut. The CeeTox panel suggests that CNB-001 produces some adverse effects on cellular adenosine triphosphate content, membrane toxicity, glutathione
content, and cell mass (or number), but only with high concentrations of the drug. After a 24-h exposure, the drug concentration that produced a half-maximal response (TC50) on the measures noted above ranges from 55 to 193 mu M. Moreover, all CNB-001-induced changes in the markers were coincident with loss of cell number, prior to acute cell death as measured by membrane integrity, suggesting a cytostatic effect of CNB-001. NXY-059 and Radicut did not have acute toxic effects on H4IIE cells. We also found that CNB-001 resulted in an inhibition of ethoxyresorufin-o-deethylase activity, indicating that the drug may affect cytochrome P4501A activity and that CNB-001 was metabolically unstable using a rat microsome assay system. For CNB-001,
an estimated in vitro efficacy/toxicity ratio AZD7762 Cell Cycle inhibitor is 183-643-fold, suggesting that there is a significant therapeutic safety window for CNB-001 and that it should be further developed as a novel neuroprotective agent to treat stroke.”
“Objective: Microtia is a developmental malformation of the external ear with genetic and environmental causes. The prevalence of microtia varies but several studies suggest increased incidence in Hispanic and African American populations. No causal genetic mutations have been identified in these populations. Mutations in the homeobox gene HOXA2 caused microtia in a single Iranian family.
Another homeobox gene, SIX2, acts downstream of HOXA2 during development and provides another possible candidate for mutational analysis.
Methods: To determine whether mutations in HOXA2 or SIX2 cause sporadic microtia, DNA sequencing analysis was performed on exons in both genes in 8 patients of Hispanic and African descent in the Bronx. Identified variants were assayed in an additional 4 patients VX-809 nmr and 100 Hispanic control samples using Sequenom MassArray to rule out causality in heterozygous patients.
Results: No mutations were identified in the coding sequence of HOXA2 or SIX2. Four novel single nucleotide variants were identified among the patient samples. These variants lie in the intron and 3′ UTR of HOXA2 and the 5′ and 3′ UTRs of SIX2. One variant in the intron of HOXA2 lies in a conserved predicted transcription factor binding site for SMARCA3. All four variants are also present at >5% frequency in Hispanic control samples, ruling out these novel variations as causal.
Conclusions: Lack of mutations in the coding regions of HOXA2 or SIX2 among the sporadic microtia patients studied indicate different etiologies.