Hsp90 Inhibitors Exhibit Resistance-Free Antiviral Activity Against Respiratory Syncytial Virus.

Hsp90 Inhibitors Exhibit Resistance-Free Antiviral Activity against Respiratory Syncytial Virus.

PLoS One. 2013; 8(2): e56762
Geller R, Andino R, Frydman J

Respiratory syncytial virus (RSV) is a major cause of respiratory illness in young children, leading to significant morbidity and mortality worldwide. Despite its medical importance, no vaccine or effective therapeutic interventions are currently available. Therefore, there is a pressing need to identify novel antiviral drugs to combat RSV infections. Hsp90, a cellular protein-folding factor, has been shown to play an important role in the replication of numerous viruses. We here demonstrate that RSV requires Hsp90 for replication. Mechanistic studies reveal that inhibition of Hsp90 during RSV infection leads to the degradation of a viral protein similar in size to the RSV L protein, the viral RNA-dependent RNA polymerase, implicating it as an Hsp90 client protein. Accordingly, Hsp90 inhibitors exhibit antiviral activity against laboratory and clinical isolates of RSV in both immortalized as well as primary differentiated airway epithelial cells. Interestingly, we find a high barrier to the emergence of drug resistance to Hsp90 inhibitors, as extensive growth of RSV under conditions of Hsp90 inhibition did not yield mutants with reduced sensitivity to these drugs. Our results suggest that Hsp90 inhibitors may present attractive antiviral therapeutics for treatment of RSV infections and highlight the potential of chaperone inhibitors as antivirals exhibiting high barriers to development of drug resistance. HubMed – drug


Efficacy and safety of traditional chinese medicine for diabetes: a double-blind, randomised, controlled trial.

PLoS One. 2013; 8(2): e56703
Ji L, Tong X, Wang H, Tian H, Zhou H, Zhang L, Li Q, Wang Y, Li H, Liu M, Yang H, Gao Y, Li Y, Li Q, Guo X, Yang G, Zhang Z, Zhou Z, Ning G, Chen Y, Paul S,

Treatment of diabetes mellitus with Traditional Chinese Medicine has a long history. The aim of this study is to establish the safety and efficacy of traditional Chinese medicine combined with glibenclamide to treat type 2 diabetes mellitus.In a controlled, double blind, multicentre non-inferiority trial, 800 patients with unsatisfactory glycemic control (fasting glucose 7-13 mmol/L and HbA1c 7-11%) were randomly assigned to receive Xiaoke Pill, a compound of Chinese herbs combined with glibenclamide, or Glibenclamide in two study groups – drug naive group, and patients previously treated with metformin monotherapy (metformin group). Outcome measures at 48 weeks were the incidence and rate of hypoglycemia, mean difference in HbA1c, and proportion of patients with HbA1c<6.5%.In drug naïve group, the total hypoglycemia rate and the mild hypoglycemic episode in the Xiaoke Pill arm were 38% (p?=?0.024) and 41% (p?=?0.002) less compared to Glibenclamide arm; in Metformin group, the average annual rate of hypoglycemia was 62% lower in Xiaoke Pill arm (p?=?0.003). Respective mean changes in HbA1c from baseline were -0.70% and -0.66% for Xiaoke Pill and Glibenclamide, with a between-group difference (95% CI) of -0.04% (-0.20, 0.12) in the drug naïve group, and those in metformin group were -0.45% and -0.59%, 0.14% (-0.12, 0.39) respectively. The respective proportions of patients with a HbA1c level <6.5% were 26.6% and 23.4% in the drug naïve group and 20.1% and 18.9% in the metformin group.In patients with type 2 diabetes and inadequate glycaemic control, treatment with Xiaoke Pill led to significant reduction in risk of hypoglycemia and similar improvements in glycemic control after 48 weeks compared to Glibenclamide.Chinese Clinical Trial Register number, ChiCTR-TRC-08000074. HubMed – drug


The interaction of the chemotherapeutic drug chlorambucil with human glutathione transferase A1-1: kinetic and structural analysis.

PLoS One. 2013; 8(2): e56337
Karpusas M, Axarli I, Chiniadis L, Papakyriakou A, Bethanis K, Scopelitou K, Clonis YD, Labrou NE

Glutathione transferases (GSTs) are enzymes that contribute to cellular detoxification by catalysing the nucleophilic attack of glutathione (GSH) on the electrophilic centre of a number of xenobiotic compounds, including several chemotherapeutic drugs. In the present work we investigated the interaction of the chemotherapeutic drug chlorambucil (CBL) with human GSTA1-1 (hGSTA1-1) using kinetic analysis, protein crystallography and molecular dynamics. In the presence of GSH, CBL behaves as an efficient substrate for hGSTA1-1. The rate-limiting step of the catalytic reaction between CBL and GSH is viscosity-dependent and kinetic data suggest that product release is rate-limiting. The crystal structure of the hGSTA1-1/CBL-GSH complex was solved at 2.1 Å resolution by molecular replacement. CBL is bound at the H-site attached to the thiol group of GSH, is partially ordered and exposed to the solvent, making specific interactions with the enzyme. Molecular dynamics simulations based on the crystal structure indicated high mobility of the CBL moiety and stabilization of the C-terminal helix due to the presence of the adduct. In the absence of GSH, CBL is shown to be an alkylating irreversible inhibitor for hGSTA1-1. Inactivation of the enzyme by CBL followed a biphasic pseudo-first-order saturation kinetics with approximately 1 mol of CBL per mol of dimeric enzyme being incorporated. Structural analysis suggested that the modifying residue is Cys112 which is located at the entrance of the H-site. The results are indicative of a structural communication between the subunits on the basis of mutually exclusive modification of Cys112, indicating that the two enzyme active sites are presumably coordinated. HubMed – drug


‘What Do I Know? Should I Participate?’ Considerations on Participation in HIV Related Research among HIV Infected Adults in Bangalore, South India.

PLoS One. 2013; 8(2): e53054
Rodrigues RJ, Antony J, Krishnamurthy S, Shet A, De Costa A

BACKGROUND: India has the highest number of HIV infected persons in the world after South Africa. Much HIV related behavioral, clinical and laboratory based research is ongoing in India. Yet little is known on Indian HIV patients’ knowledge of research, their processes of decision making and motives for participation. We aimed to explore these areas among HIV infected individuals to understand their reasons for participating in research. METHODOLOGYPRINCIPAL FINDINGS: This is a cross sectional survey among 173 HIV infected adults at a tertiary level hospital in Bangalore, India, done between October 2010 and January 2011. A pre-tested questionnaire was administered to the participants by trained research assistants to assess their knowledge regarding research, willingness to participate, decision making and determinants of participation. Participants were presented with five hypothetical HIV research studies. Each study had a different level of intervention and time commitment. Of respondents, 103(60%), said that research meant ‘to discover something new’ and 138(80%) were willing to participate in research. A third of the respondents were unaware of their right to refuse participation. Willingness to participate in research varied with level of intervention. It was the lowest for the hypothetical study involving sensitive questions followed by the hypothetical drug trial; and was the highest for the hypothetical cross sectional questionnaire based study (p<0.0015). Individual health benefits and altruism were the primary motives for participation in research and indicate the presence of therapeutic misconception. Women were less likely to make autonomous decisions for participation in interventional studies. CONCLUSIONSSIGNIFICANCE: Despite a majority willing to participate, over a third of respondents did not have any knowledge of research or the voluntary nature of participation. This has ethical implications. Researchers need to focus on enabling potential research participants understand the concepts of research, promote autonomous decisions, especially by women and restrict therapeutic misconception. HubMed – drug