Xiaorong Liu

Rescue of ATP7B function in hepatocyte-like cells from Wilson's disease induced pluripotent stem cells using gene therapy or the chaperone drug curcumin

Directed hepatocyte differentiation from human induced pluripotent stem cells (iPSCs) potentially provides a unique platform for modeling liver genetic diseases and performing drug-toxicity screening in vitro. Wilsons disease is a genetic disease caused by mutations in the ATP7B gene, whose product is a liver transporter protein responsible for coordinated copper export into bile and blood. Interestingly, the spectrum of ATP7B mutations is vast and can influence clinical presentation (a variable spectrum of hepatic and neural manifestations), though the reason is not well understood. We describe the generation of iPSCs from a Chinese patient with Wilsons disease that bears the R778L Chinese hotspot mutation in the ATP7B gene. These iPSCs were pluripotent and could be readily differentiated into hepatocyte-like cells that displayed abnormal cytoplasmic localization of mutated ATP7B and defective copper transport. Moreover, gene correction using a self-inactivating lentiviral vector that expresses codon optimized-ATP7B or treatment with the chaperone drug curcumin could reverse the functional defect in vitro. Hence, our work describes an attractive model for studying the pathogenesis of Wilsons disease that is valuable for screening compounds or gene therapy approaches aimed to correct the abnormality. In the future, once relevant safety concerns (including the stability of the mature liver-like phenotype) and technical issues for the transplantation procedure are solved, hepatocyte-like cells from similarly genetically corrected iPSCs could be an option for autologous transplantation in Wilsons disease.

Evaluation of Aminohydantoins as a Novel Class of Antimalarial Agents

Given the threat of drug resistance, there is an acute need for new classes of antimalarial agents that act via a unique mechanism of action relative to currently used drugs. We have identified a set of druglike compounds within the Tres Cantos Anti-Malarial Set (TCAMS) which likely act via inhibition of a Plasmodium aspartic protease. Structure-activity relationship analysis and optimization of these aminohydantoins demonstrate that these compounds are potent nanomolar inhibitors of the Plasmodium aspartic proteases PM-II and PM-IV and likely one or more other Plasmodium aspartic proteases. Incorporation of a bulky group, such as a cyclohexyl group, on the aminohydantion N-3 position gives enhanced antimalarial potency while reducing inhibition of human aspartic proteases such as BACE. We have identified compound 8p (CWHM-117) as a promising lead for optimization as an antimalarial drug with a low molecular weight, modest lipophilicity, oral bioavailability, and in vivo antimalarial activity in mice.

Synthesis of Deuterated Benzopyran Derivatives as Selective COX-2 Inhibitors with Improved Pharmacokinetic Properties.

We designed a series of specifically deuterated benzopyran analogues as new COX-2 inhibitors with the aim of improving their pharmacokinetic properties. As expected, the deuterated compounds retained potency and selectivity for COX-2. The new molecules possess improved pharmacokinetic profiles in rats compared to their nondeuterated congeners. Most importantly, the new compounds showed pharmacodynamic efficacy in several murine models of inflammation and pain. The benzopyran derivatives were separated into their enantiomers, and the activity was found to reside with the S-isomers. To streamline the synthesis of the desired S-isomers, an organocatalytic asymmetric domino oxa-Michael/aldol condensation reaction was developed for their preparation.

Evaluation of spiropiperidine hydantoins as a novel class of antimalarial agents.

Given the rise of parasite resistance to all currently used antimalarial drugs, the identification of novel chemotypes with unique mechanisms of action is of paramount importance. Since Plasmodium expresses a number of aspartic proteases necessary for its survival, we have mined antimalarial datasets for drug-like aspartic protease inhibitors. This effort led to the identification of spiropiperidine hydantoins, bearing similarity to known inhibitors of the human aspartic protease β-secretase (BACE), as new leads for antimalarial drug discovery. Spiropiperidine hydantoins have a dynamic structure-activity relationship profile with positions identified as being tolerant of a variety of substitution patterns as well as a key piperidine N-benzyl phenol pharmacophore. Lead compounds 4e (CWHM-123) and 12k (CWHM-505) are potent antimalarials with IC50 values against Plasmodium falciparum 3D7 of 0.310 μM and 0.099 μM, respectively, and the former features equivalent potency on the chloroquine-resistant Dd2 strain. Remarkably, these compounds do not inhibit human aspartic proteases BACE, cathepsins D and E, or Plasmodium plasmepsins II and IV despite their similarity to known BACE inhibitors. Although the current leads suffer from poor metabolic stability, they do fit into a drug-like chemical property space and provide a new class of potent antimalarial agents for further study.

Pentafluorosulfanyl-Substituted Benzopyran Analogues As New Cyclooxygenase-2 Inhibitors with Excellent Pharmacokinetics and Efficacy in Blocking Inflammation

In this report, we disclose the design and synthesis of a series of pentafluorosulfanyl (SF5) benzopyran derivatives as novel COX-2 inhibitors with improved pharmacokinetic and pharmacodynamic properties. The pentafluorosulfanyl compounds showed both potency and selectivity for COX-2 and demonstrated efficacy in several murine models of inflammation and pain. More interestingly, one of the compounds, R,S-3a, revealed exceptional efficacy in the adjuvant induced arthritis (AIA) model, achieving an ED50 as low as 0.094 mg/kg. In addition, the pharmacokinetics of compound R,S-3a in rat revealed a half-life in excess of 12 h and plasma drug concentrations well above its IC90 for up to 40 h. When R,S-3a was dosed just two times a week in the AIA model, efficacy was still maintained. Overall, drug R,S-3a and other analogues are suitable candidates that merit further investigation for the treatment of inflammation and pain as well as other diseases where COX-2 and PGE2 play a role in their etiology.

Profile Control Effect and Mechanism Analysis of Fly Ash

Abstract Fly ash is a coal-fired power plant waste. Its main chemical ingredient is aluminum silicate and its exterior appearance is mainly agraphitic glass phase sphere with loose structure and different size, characteristic of a wide source and low cost. In hydrothermal conditions, Holler and Wirsching took the lead to use fly ash and alkaline (NaOH or KOH) in the synthesis of zeolite. Aimed at actual demand of improving the absorption water profile of flooding well, in regards to the blockage of reservoir pore, the article explores the ingredient constitution and technological conditions for part transformation of fly ash into the zeolite under the conditions of hydrothermal condition. The chemical composition and the structural feature of the exterior appearance of the modified fly ash are studied, as are the blocking effect and profile control mechanism, all of which have important application value to improve the blocking effect and increasing oil recovery.

Abstract LB-224: Anti-tumor effects of ECP-1014 in combination with erlotinib in HT-29 xenograft murine colon carcinoma model

Objective: The objective of this study was to evaluate the effect of ECP-1014, a new selective COX-2 inhibitor, in combination with erlotinib on tumor growth in a HT-29 xenograft murine colon carcinoma model. Pre-clinical studies suggest that cyclooxygenase-2 (COX-2) inhibitors can affect most of the acquired epidermal growth factor (EGFR) resistance pathways. Therefore, the hypothesis was that combining a COX-2 inhibitor with an EGFR inhibitor such as erlotinib would result in superior tumor control versus either agent alone. Methods: 48 CB17-SCID male mice were implanted with 2-5×106 HT-29 cells. Once tumors reached approximately 75 mm3 in size mice were randomly assigned to 6 treatment groups: vehicle (G1), 1mg/kg ECP-1014 (G2), 1 mg/kg ECP-1014 + 50 mg/kg erlotinib (G3), 10 mg/kg ECP-1014 (G4), 10mg/kg ECP-1014 +50 mg/kg erlotinib (G5), 50 mg/kg erlotinib (G6). ECP-1014 and erlotinib were administered daily by oral gavage, beginning immediately following randomization and continued for 22 days. Tumor volume measurements were taken every 3 days. On day 24 tumor tissue was collected from each animal to determine ECP-1014, erlotinib, and PGE2 levels. Tumor samples were prepared using protein precipitation after grinding in nitrogen. 0.1μL of 50% methanol water solution and 50 mg tumor sample were vortexed for 3 minutes, and 200μL acetonitrile containing the internal standard was addd and vortexed for an additional 5 minutes. The tubes were then placed in the centrifuge at 16000 G for 40 minutes at 4oC. 100μL of the supernatant was transferred to a 96-well plate for analysis by LC-MS/MS.) Results: All animals developed tumors. There was no difference between treatment groups in body weights over the course of the study. The combinations of ECP-1014 + erlotinib produced a 66% (G3) and 60% (G5) slowing of tumor growth when compared to vehicle (G1). ECP-1014 10 mg/kg (G4) produced 51% suppression of tumor growth alone compared to G1, whereas erlotinib alone produced a 38% suppression of tumor growth alone when compared to G1. The addition of erlotinib produced a 1.5X increase in the tumor levels of ECP-1014 when compared to ECP-1014 tumor levels alone (mean+SD, 1479+652 to 2244+887μg/g for G3; 9720+2759 to 14745+4758μg/g for G5). ECP-1014 alone or in combination with erlotinib suppressed PGE-2 levels in the tumor from 66-100%. Summary: ECP-1014 alone was superior to erlotinib 50 mg/kg in slowing tumor growth. In a separate study using the identical model we demonstrated that 0.3 mg/kg 1014 was shown to be roughly equipotent to 10 mg/kg celecoxib both in terms of tumor control and PGE2 suppression. However, the combination of ECP-1014 + erlotinib showed the greatest tumor growth suppression when compared to vehicle and each therapy alone. There was little difference between ECP-1014 1 and 10 mg/kg dose groups when combined with erlotinib. Citation Format: Bobby W. Sandage, Micky Tortorella, Yanmei Zhang, Zhengchao Tu, Yican Wang, Xiaorong Liu, John J. Talley. Anti-tumor effects of ECP-1014 in combination with erlotinib in HT-29 xenograft murine colon carcinoma model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-224.