XiangDi Wang

A crystallin gene network in the mouse retina.

The present study was designed to examine the regulation of crystallin genes and protein in the mouse retina using the BXD recombinant inbred (RI) strains. Illumina Sentrix BeadChip Arrays (MouseWG-6v2) were used to analyze mRNA levels in 75 BXD RI strains along with the parental strains (C57Bl/6J and DBA/2J), and the reciprocal crosses in the Hamilton Eye Institute (HEI) Retina Dataset (www.genenetwork.org). Protein levels were investigated using immunoblots to quantify levels of proteins and indirect immunohistochemistry to define the distribution of protein. Algorithms in the Genomatix program were used to identify transcription factor binding sites common to the regulatory sequences in the 5 regions of co-regulated set of crystallin and other genes as compared to a set of control genes. As subset of genes, including many encoding lens crystallins is part of a tightly co-regulated network that is active in the retina. Expression of this crystallin network appears to be binary in nature, being expressed either at relatively low levels or being highly upregulated. Relative to a control set of genes, the 5 regulatory sequences of the crystallin network genes show an increased frequency of a set of common transcription factor-binding sites, the most common being those of the Maf family. Chromatin immunoprecipitation of human lens epithelial cells (HLEC) and rat retinal ganglion cells (RGC) confirmed the functionality of these sites, showing that MafA binds the predicted sites of CRYGA and CRYGD in HLE and CRYAB, CRYGA, CRYBA1, and CRYBB3 in RGC cells. In the retina there is a highly correlated group of genes containing many members of the α- β- and γ-crystallin families. These genes can be dramatically upregulated in the retina. One transcription factor that appears to be involved in this coordinated expression is the MAF family transcription of factors associated with both lens and extralenticular expression of crystallin genes.

Treating Retinoblastoma in Tissue Culture and in a Rat Model with a Novel Isoquinoline Derivative

PURPOSE. To investigate the effectiveness of a novel isoquinoline derivative, EDL-155, in killing retinoblastoma in vitro and in vivo. METHODS. Dose-response curves were generated in which Y79 retinoblastoma cells tagged with luciferase (Y79-Luc) were treated with serial concentrations of EDL-155. Electron microscopy was used to evaluate the ultrastructural morphology of EDL-155-treated Y79 cells. To determine whether autophagy was induced in EDL-155-treated Y79-Luc cells, staining with acridine orange and LC-3 immunoblot analysis was performed. To evaluate the efficacy of EDL-155 in vivo, Y79-Luc retinoblastoma cells were injected into the vitreous cavity of newborn rats, followed by periocular injections of EDL-155 (20 mg/kg/day) or an equivalent dosage of saline. RESULTS. EDL-155 appeared to destroy the retinoblastoma cells in vitro with an EC(50) of 9.1 micriM. EDL-155-treated retinoblastoma cells displayed a lack of viable mitochondria and the presence of autophagosomes wrapped in the characteristic double membranes. Acridine orange staining of EDL-155-treated retinoblastoma cells demonstrated the accumulation of vacuoles, and the immunoblots displayed a shift in molecular weight of LC-3, indicative of incorporation into autophagosome vesicles. In the retinoblastoma animal model, four doses of EDL-155 were delivered over 4 days, which was sufficient to see a significant decrease (P = 0.01) in viable intraocular tumors. Seven of the 25 rats treated with EDL-155 had no detectable living tumor. No significant decrease in viable tumor was observed in control animals. CONCLUSIONS. EDL-155 appears to eliminate retinoblastoma cells by disrupting mitochondria and inducing autophagy. Local delivery of EDL-155 may be an effective therapy for some types of ocular cancers.

Plasma and cerebrospinal fluid pharmacokinetics of the novel tetrahydroisoquinoline EDL-155 in rats

PurposeTetrahydroisoquinolines (THIs) have demonstrated anti-cancer activity in rodent models of glioma, a form of brain cancer refractory to therapeutic intervention. In this study, peripheral and cerebrospinal fluid (CSF) pharmacokinetics in rats were determined to assess the drug developability of the novel THI EDL-155 for the treatment of glioma.MethodsSerial blood and CSF samples were collected from rats following intravenous bolus administration of EDL-155 (10–20xa0mg/kg). Samples were analyzed by LC/MS/MS. Pharmacokinetic analyses using compartmental and noncompartmental methods were performed using the computer program WinNonlin. Plasma protein binding was measured using the charcoal adsorption method. The in vivo efficacy of EDL-155 (i.p. 20xa0mg/kg twice daily for 7xa0days) was assessed in rats with stereotactically implanted C6 glioma cells into the caudate.ResultsEDL-155 plasma concentration data were described by a one-compartment model. EDL-155 demonstrated rapid clearance (342.5xa0±xa049.9xa0ml/min/kg), high volume of distribution (13.0xa0±xa01.2xa0l/kg) and a terminal half-life of 23.7xa0±xa01.5xa0min. Dose-normalized CSF area under the curve (AUCCSF) as a percentage of peripheral exposure (AUCPlasma) was 1.4%. EDL-155 was highly bound to plasma proteins (>93%). Intracranial tumor volume at 7xa0days post-implantation was approximately 30% smaller in animals treated with EDL-155 when compared to vehicle control animals (13.2xa0±xa05.3xa0mm3 vs. 18.7xa0±xa06.3xa0mm3; Pxa0=xa00.04).ConclusionHigh clearance and extensive protein binding limit the brain availability of EDL-155 following systemic administration. EDL-155 treatment resulted in reduced tumor size despite limited blood brain barrier penetrability, which suggests that analogs with increased metabolic stability and brain penetrability may provide a therapeutic option for primary central nervous system tumors such as glioma. On-going studies are focused on the design, synthesis, and testing of novel analogs based upon these findings.

Synthesis and in vitro evaluation of novel 1,2,3,4-tetrahydroisoquinoline derivatives as potent antiglioma agents.

Glioblastoma Multiforme (GBM) continues to demand improved chemotherapeutic solutions. In order to discover novel chemotherapeutic agents for GBM, we identified novel tetrahydroisoquinoline (THI) analogs as antiglioma agents. The present study reports the design, synthesis and in vitro evaluation of new THI derivatives in four established human glioma cell lines (T98, U87, LN18 and A172). Our structure activity relationship (SAR) studies revealed that the important modification of the carbon linker between the biphenyl and THI ring yielded EDL-360 (12) as a potent antiglioma agent (LN18; IC50: 5.42 ± 0.06 μM) and is considered to be our new lead drug candidate for further preclinical studies.