Monday, February 16, 2015

'Mad Cow' discovery points to possible neuron killing mechanism behind alzheimer’s and parkinson’s diseases

Scientists from the Florida campus of The Scripps Research Institute (TSRI) have for the first time discovered a killing mechanism that could underpin a range of the most intractable neurodegenerative diseases such as Alzheimer’s, Parkinson’s and ALS.

The new study, published recently in the journal Brain, revealed the mechanism of toxicity of a misfolded form of the protein that underlies prion diseases, such as bovine spongiform encephalopathy (“mad cow disease”) and its human equivalent, Creutzfeldt-Jakob disease.

Our study reveals a novel mechanism of neuronal death involved in a neurodegenerative protein-misfolding disease,” said Corinne Lasmézas, a TSRI professor who led the study. “Importantly, the death of these cells is preventable. In our study, ailing neurons in culture and in an animal model were completely rescued by treatment, despite the continued presence of the toxic misfolded protein. This work suggests treatment strategies for prion diseases—and possibly other protein misfolding diseases such as Alzheimer’s.

Wednesday, February 11, 2015

Diabetes drug can boost efficacy of TB medication without causing drug resistance

In continuation of my update on Metformin

A more effective treatment for tuberculosis (TB) could soon be available as scientists have discovered that Metformin (MET), a drug for treating diabetes, can also be used to boost the efficacy of TB medication without inducing drug resistance.

This discovery was made by a team of international scientists led by the Singapore Immunology Network (SIgN), a research institute under the Agency for Science, Technology and Research (A*STAR), Singapore.

TB is an air-borne infectious disease caused by a bacterium called Mycobacterium tuberculosis (Mtb), which often infects the lungs. Even though drugs are available to treat the disease, TB continues to be a major threat to public health, killing close to 1.5 million people every year .

Conventional drugs used to treat TB usually adopt a pathogen-targeted strategy which attacks and kills bacteria directly. This approach has caused Mtb strains to acquire drug resistance, making existing treatments become increasingly ineffective and resulting in a pressing need to design new therapeutic strategies for the disease.

MET as an adjunct treatment for TB

The team of scientists led by SIgN began searching for drugs that could control Mtb replication indirectly. They screened FDA-approved drugs and identified MET, an old anti-diabetic drug that could defend Mtb invasion without targeting the bacteria directly. Instead, MET targets the host cells to trigger the production of a chemical which then damages Mtb and stops its replication. Such indirect, host-targeted approach is less likely to engender drug resistance. The team also discovered that MET improves the efficacy of conventional anti-TB drugs when used in combination with them.

The scientists then validated the findings with patient data provided by the Tuberculosis Clinical Unit at the Tan Tock Seng Hospital, and consequently verified that the use of MET is indeed associated with improved TB control and decreased disease severity. This anti-diabetic drug is therefore a promising adjunctive therapy that could enhance the effectiveness of existing TB treatments. As it is a drug that is currently in use, another benefit of using MET as an adjunct treatment for TB is that it is likely to shorten the time required for clinical trials.


Monday, February 9, 2015

FL118 agent shows efficacy as personalized, targeted therapy for certain cancer tumors




A team led by Fengzhi Li, PhD, and Xinjiang Wang, PhD, of Roswell Park Cancer Institute (RPCI) has reported new findings regarding therapeutic targets of the novel anticancer agent FL118. Previous studies from these researchers have showed that FL118 induces cancer cell death, or apoptosis, by inhibiting expression of multiple cell-survival proteins (survivin, Mcl-1, XIAP or cIAP2). Study results published in the peer-reviewed American Association for Cancer Research journal Cancer Research  showed that FL118 can also activate   the p53 tumor-suppressor pathway in cancer cells, encouraging cell senescence,    or aging. In both processes, FL118 demonstrates potent antitumor efficacy,   suggesting additional applications as a personalized, targeted therapy for certain cancer tumors.

In a study of preclinical models of colorectal cancer, the researchers identified an underlying mechanism for the activation of p53 by FL118. The agent activates the p53 tumor-suppressor protein largely independent of ataxia telangiectasia mutated (ATM)-dependent DNA damage-mediated p53 activation. ATM-dependent activation of p53 is usually induced by many — if not all  types of DNA-damage drugs, including camptothecin compounds such as irinotecan and topotecan,  leading  the authors  to  conclude  that  FL118's mechanisms of action are distinct among camptothecin analogues.


"While FL118 is an analogue of irinotecan and topotecan, two FDA-approved cancer drugs that are also based on the naturally occurring compound camptothecin, our findings add further evidence that FL118 has novel mechanisms of action that may make it especially potent against solid tumors and especially effective as a well-tolerated, targeted therapy," said Dr. Li, an Associate Professor of Oncology in the Department of Pharmacology and Therapeutics.





















FL118 agent shows efficacy as personalized, targeted therapy for certain cancer tumors

Friday, February 6, 2015

Addition of S-1 to cisplatin plus radiotherapy ‘favourable’ in NSCLC

In continuation of my update on cisplatin and 5-fluorouracil derivative S-1v



Research suggests that treatment with cisplatin plus S-1 together with thoracic radiotherapy is relatively efficacious and tolerable in patients with locally advanced non-small-cell lung cancer (NSCLC).

Although cisplatin-based chemotherapy with thoracic radiotherapy is a standard treatment for unresectable, locally advanced NSCLC, the outcomes are not satisfactory, explain Katsuyuki Hotta, from Okayama University Hospital in Japan, and colleagues. They investigated the effect of adding the 5-fluorouracil derivative S-1 to the standard treatment in a phase II trial, the primary endpoint of which was the response rate.

A total of 48 patients with stage III NSCLC received cisplatin plus S-1 (at a dose of 40 mg/m2 twice daily from days 1–14 and 29–42 of treatment) with concurrent thoracic irradiation, of whom 37 had a partial response, giving an overall response rate (ORR) of 77%.


Thursday, February 5, 2015

First-line dacomitinib may improve advanced NSCLC survival



Dacomitinib.svg 




Preliminary research suggests that the second-generation tyrosine kinase inhibitor (TKI) dacomitinib (see right structure)may improve progression-free survival (PFS) in patients with advanced non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations.

Noting that the majority of patients develop resistance to the first-generation TKIs, such as gefitinib and erlotinib (below structures from left and right side respectively), Pasi Jänne (Dana Farber Cancer Institute, Boston, Massachusetts, USA) and co-workers explain that alternative agents are needed to improve patient outcomes.

Gefitinib structure.svg Erlotinib Structural Formulae.png

The open-label, phase II trial included 89 treatment-naïve patients with stage IIIB or IV NSCLC who were selected for dacomitinib once-daily treatment on the basis of clinical markers (never or former light smokers) or molecular markers (absence of KRASmutation in non-Asian patients or EGFR mutation).

First-line dacomitinib may improve advanced NSCLC survival

Wednesday, February 4, 2015

Isis announces top-line results from ISIS-PTP1B Rx Phase 2 study in type 2 diabetes patients

Isis announces top-line results from ISIS-PTP1B Rx Phase 2 study in type 2 diabetes patients

Added benefit of daclatasvir drug not proven for chronic hepatitis C infection

In continuation of my update on daclatasvir Daclatasvir.svg


The drug daclatasvir (trade name Daklinza) has been available since August 2014 for the treatment of adults with chronic hepatitis C (CHC) infection. The German Institute for Quality and Efficiency in Health Care (IQWiG) examined in a dossier assessment whether this new drug offers an added benefit over the appropriate comparator therapy.

The drug manufacturer presented data for patients without cirrhosis of the liver who are infected with hepatitis C virus (HCV) genotype 1, and for patients with HCV genotype 4. However, these data are unsuitable in various aspects to prove an added benefit.

The manufacturer dossier contained no data at all for three further patient groups with HCV genotype 1 infection (pretreated patients, untreated patients with cirrhosis of the liver, and patients with HIV coinfection) as well as for patients with HCV genotype 3 (with compensated cirrhosis and/or treatment-experienced).

Tuesday, February 3, 2015

Penn researchers find effective way to inhibit inflammatory response during kidney dialysis

Frequent kidney dialysis is essential for the approximately 350,000 end-stage renal disease (ESRD) patients in the United States. But it can also cause systemic inflammation, leading to complications such as cardiovascular disease and anemia, and patients who rely on the therapy have a five-year survival rate of only 35 percent. Such inflammation can be triggered when the complement cascade, part of the body's innate immune system, is inadvertently activated by modern polymer-based dialysis blood filters. New work by Penn researchers has found an effective way to avoid these problems by temporarily suppressing complement during dialysis. Their work appears online in Immunobiology ahead of print.

Compstatin Ile-Cys-Val-Val-Gln-Asp-Trp-Gly-His-His-Arg-Cys-Thr-NH2 (Disulfide bridge: 2 -12)
Over the past several years, lead author John Lambris, PhD, the Dr. Ralph and Sallie Weaver Professor of Research Medicine, Perelman School of Medicine at the University of Pennsylvania, and his colleagues have developed small molecule versions of the drug compstatin, which inhibits a component of the complement immune response called C3. Lambris explains that this next-generation compound, called Cp40, "is a small peptide similar to cyclosporine in many aspects, however it uses a different mechanism of action."


Previous studies by Lambris and his team, in which modern polymer-based hemodialysis filters were perfused with human blood, showed significant complement activation and an increase in inflammatory biomarkers. This response could be suppressed using compstatin, suggesting that it might be used in dialysis to decrease the inflammatory response side effect.
The new study took place in non-human primates to validate Cp40's complement-inhibiting properties in whole animals. Even after undergoing a single session of dialysis using a pediatric hemodialysis filter with high biocompatibility, healthy animals showed strong complement activation with 5 percent of their C3 being converted to a form that can trigger inflammation and stimulate the immune system.

Ref : http://www.upenn.edu/pennnews/news/penn-researchers-tame-inflammatory-response-kidney-dialysis

Sunday, February 1, 2015

SLU researcher discovers new information about how antibiotics stop staph infections


In research published in Proceedings of the National Academy of Sciences, assistant professor of biochemistry and molecular biology at Saint Louis University Mee-Ngan F. Yap, Ph.D., discovered new information about how antibiotics like azithromycin stop staph infections, and why staph sometimes becomes resistant to drugs.

Her evidence suggests a universal, evolutionary mechanism by which the bacteria eludes this kind of drug, offering scientists a way to improve the effectiveness of antibiotics to which bacteria have become resistant.

Staphylococcus aureus (familiar to many as the common and sometimes difficult to treat staph infection) is a strain of bacteria that frequently has become resistant to antibiotics, a development that has been challenging for doctors and dangerous for patients with severe infections.

Yap and her research team studied staph that had been treated with the antibiotic azithromycin and learned two things: One, it turns out that the antibiotic isn't as effective as was previously thought. And two, the process that the bacteria use to evade the antibiotic appears to be an evolutionary mechanism that the bacteria developed in order to delay genetic replication when beneficial.

The team studied the way antibiotics work within the ribosome, the site where bacteria translates the genetic codes into protein. When the bacteria encounter a potential problem in copying its genetic material, as posed by an antibiotic, it has a mechanism to thwart antibiotic inhibition by means of "ribosome stalling" that is mediated by special upstream peptide elements.

Ref  http://www.pnas.org/content/111/43/15379.abstract?sid=94feec3e-058d-4239-97fb-bb9db8f148bb