Drugs – Health Care
Tag

Drugs

Browsing

Viruses are parasites. The only way they can grow is by hijacking their hosts. When they infect a human host, viruses use human proteins to multiply and modify the human cells to sustain the infection. At the same time, the human host activates defense mechanisms to fight the infection.

Most current drugs against viral infections target the virus itself. But scientists are interested in developing therapies that aim for host proteins instead, or the genes that produce them, in part because such therapies are believed less likely to elicit drug resistance. A detailed understanding of virus-host interactions is crucial to the success of this strategy.

A team of Gladstone Institutes scientists led by Senior Investigator Nevan Krogan, PhD, has been cataloging host proteins that physically bind to virus proteins. These physical interactions identify human proteins that the virus can use to infect cells and propagate. However, they don't reveal how host proteins work together to facilitate infection.

To address this gap, Krogan and staff scientist David Gordon, PhD, with colleagues at UC San Francisco (UCSF), University College Dublin, and the Mount Sinai School of Medicine, have developed a new way to understand how host cells control HIV infection in human cells.

Their approach entails disrupting host genes rather than proteins. It is based on the idea, pioneered by Krogan, that you obtain richer information about the functions of genes–and the proteins they encode–when you disable the genes in pairs, instead of one by one. In a paper published in Molecular Cell, the team describes a map of the genes controlling HIV infection in human cells, which they built by assessing more than 63,000 combinations of human genes associated with HIV infection.

HIV is a major public health concern, with an estimated 36.7 million people living with chronic infection, and over 20.9 million people receiving continuous treatment. Studying the impact of gene disruptions in pairs rather than one by one yields important information on how genes work together to mediate virus infection, highlighting processes we can target with drugs to inhibit infection."

Nevan Krogan, Ph.D., senior investigator, professor of Cellular and Molecular Pharmacology at UCSF, and the director of the UCSF Quantitative Biosciences Institute

The map, which the team refers to as a viral epistasis map (vE-MAP), is an essential advance for HIV research in several other ways. For one thing, it uncovers a previously unsuspected set of genes required for the growth of the virus in human cells. For another, the vE-MAP can be used to analyze how different HIV mutants affect host cells or to test drugs that disrupt HIV-host interactions.

Strength in numbers

The vE-MAP is an adaptation of the E-MAP, which Krogan and his colleagues pioneered and refined over the past 15 years to identify genes that control how cells grow. At the core of this approach is the Krogan lab's ability to disrupt a large number of genes, test them in pairs, and analyze the results via sophisticated computational methods.

"The principle behind E-MAPs is that when you disrupt two genes at once and examine the impact on a cell, you sometimes see effects that are significantly larger or smaller than you would have predicted from the effect of disrupting either gene alone," said Krogan.

These unexpected effects suggest that the functions of the two genes are related. Moreover, by carrying out these pairwise disruptions across hundreds of genes, scientists can find groups of genes with similar patterns of interactions, a sign that they are likely to take part in the same molecular process.

"And so, instead of finding important genes one at a time, you can all at once identify multiple, distinct networks of genes affecting the process you are studying," said Gordon.

Related Stories

  • Promising HIV vaccine fails in a large-scale clinical trial
  • Vitamin E can safely treat fatty liver disease in patients with HIV
  • HIV antibody therapy improves immune function

The E-MAP approach has mostly been used to study cell growth. Gordon, in collaboration with a student from University College Dublin, Ariane Watson, had to modify it to study virus infection. The most tricky part was to implement a sophisticated data acquisition and scoring system, which allowed them to measure HIV infection accurately across hundreds of thousands of samples, and compare the effect of pairwise and single-gene disruptions.

It would be an overwhelming effort to test all combinations of the over 20,000 protein-coding genes in the human genome. Instead, the scientists focused on genes already suspected to influence HIV biology. In particular, they used the genes encoding a large number of human proteins that the Krogan lab had previously found to bind to HIV proteins. In all, they included over 350 genes in their analysis and tested over 63,000 pairwise disruptions.

New players at the HIV-host interface

Although HIV is one of the best-studied human viruses and is now well-controlled by antiretroviral therapy, there is no cure for HIV/AIDS. Moreover, antiretroviral therapy is costly, which can make it impractical in resource-poor countries. The search for new means of halting or eradicating the virus is, therefore, still a priority.

Among the genes that stood out in the vE-MAP were several members of the CNOT family, whose role in HIV biology had never before been established. The authors demonstrated that the CNOT complex promotes HIV infection by suppressing innate immunity in CD4+ T cells, the type of immune cells that HIV preferentially targets in humans. Innate immunity is a defense mechanism by which host cells can fight infection.

"The impact of CNOT on innate immunity is a key, yet previously unrecognized, host pathway critical to HIV infection. It will serve as a potential novel therapeutic target in future studies," said Krogan.

For instance, scientists can now study if targeting the CNOT complex with drugs could be a way to help HIV patients fight the infection more effectively.

Furthermore, the vE-MAP uncovered genes that had little impact when disrupted individually, but a great effect when tested together.

"These genes would be overlooked in classic, single-gene disruption experiments," said Gordon. "They confirm the potential of the vE-MAP to uncover new mechanisms by which HIV interacts with human cells."

Combining drugs that target two of these genes at the same time might thus be a promising therapeutic strategy, especially for a virus such as HIV/AIDS, which has evolved multiple ways of tapping its hosts' resources.

The vE-MAP was also able to pick up genes that specifically interact with a known HIV mutant. This observation bodes well for the ability of the vE-MAP to identify distinct host factors affecting the various forms of HIV, or the virus mutants that arise in response to currently available drugs.

Additional testing with a drug known to interfere with HIV-associated human proteins gives the authors confidence that their vE-MAP approach could, in the future, be used to screen for novel anti-HIV drugs and to understand their mode of action.

"This vE-MAP provides an unprecedented view of how HIV hijacks and rewires the cellular machinery in human cells during infection," said Krogan. "It will generate many new ideas and avenues to identify and test novel therapies."

And the benefits may not be limited to HIV research.

"Our work is proof-of-principle that the vE-MAP approach is a powerful way to map out the interface between HIV and human cells, and to uncover new therapeutic avenues," said Gordon. "We now look forward to testing it on other pathogens."

Source:

Gladstone Institutes

After 50 years of research and the testing of over 1,000 drugs, there is new hope for preserving brain cells for a time after stroke. Treating acute ischemic stroke patients with an experimental neuroprotective drug, combined with a surgical procedure to remove the clot improves outcomes as shown by clinical trial results published today in The Lancet.

The multi-center, double-blinded, randomized trial, led by a team at the Cumming School of Medicine's (CSM) Hotchkiss Brain Institute and Alberta Health Services, investigates the use of the neuroprotective drug nerinetide, developed by NoNO Inc, in two scenarios in the same trial. In one scenario, nerinetide is given to patients in addition to the clot-busting drug alteplase. In the second scenario, patients who were not suitable for alteplase received only nerinetide. Both groups of patients had concurrent endovascular treatment (EVT) to remove the clot.

"Compared to placebo, almost 20 per cent more patients who received nerinetide along with endovascular treatment, but did not receive alteplase, recovered from a devastating stroke – a difference between paralysis and walking out of the hospital," says Dr. Michael Hill, MD, a neurologist at Foothills Medical Centre (FMC) and professor in the departments of Clinical Neurosciences and Radiology at the CSM. "In the patients who received both drugs, the alteplase negated the benefits of the nerinetide."

Hill says the study provides evidence of a biological pathway that protects brain cells from dying when they are deprived of blood flow. Nerinetide targets the final stage of the brain cell's life by stopping the production of nitric oxide within the cell.

"We really believe this is a new scientific observation," says Hill. "There is evidence nerinetide promotes brain cell survival, offering neuroprotection until we can extract the clot. It opens the door to a new way of treating stroke."

Images of patients' brains from the study show the expected size of the damage from the stroke is sizeably reduced when nerinetide is administered and EVT is performed among patients not concurrently receiving alteplase.

After so many studies investigating neuroprotective drugs failed, we are extremely excited by these results. While nerinetide is not approved for use yet, it shows the potential of a new tool to promote recovery from stroke."

Dr. Mayank Goyal, MD, PhD, neuroradiologist at the FMC, and clinical professor in the Department of Radiology at the CSM

Related Stories

  • Researchers design new drug cocktail to kill brain and soft tissue cancers
  • What the western diet is doing to your brain
  • Research looks at prenatal cannabis use

Worldwide, 15 million people suffer a stroke each year – that's one every nine minutes in Canada and every 90 seconds in the United States. The results can be devastating. Ischemic stroke, the most common, is caused by a clot in a blood vessel in the brain. The sudden loss of blood flow causes brain cells to die, which can permanently affect speech, vision, balance and movement.

The international trial enrolled 1,105 patients between March 2017 and August 2019 at centres in North America, Europe, Australia, and Asia – a global academic collaboration bringing together scientists, clinicians, funding agencies, and industry.

"The collaboration between NoNO Inc., the University of Calgary and investigators at 48 leading stroke hospitals around the world has shown how effective such an academic-industry partnership can be in running high-quality, foundational stroke trials that can lead to positive changes in clinical practice," says Dr. Michael Tymianski, MD, PhD, CEO of NoNO Inc. and the inventor of nerinetide.

The results in the current study, called the ESCAPE-NA1 Trial, build on the success of the ESCAPE trial, in which the Calgary Stroke Program proved that a clot retrieval procedure known as EVT can dramatically improve patient outcomes after an acute ischemic stroke. During the procedure, a catheter is inserted in the groin and guided through blood vessels into the brain. A tiny metal mesh device is used to grab the clot and pull it out. The current study investigates whether administering nerinetide in addition to clot retrieval improves the patient's ability to recover.

Source:

University of Calgary

Journal reference:

Hill, M.D, et al. (2020) Efficacy and safety of nerinetide for the treatment of acute ischaemic stroke (ESCAPE-NA1): a multicentre, double-blind, randomised controlled trial. The Lancet. doi.org/10.1016/S0140-6736(20)30258-0.

When you're facing a cancer diagnosis with an average survival span of 12 to 18 months, every milestone is a victory. That makes each wedding invitation, graduation announcement and birthday photo that UCI neuro-oncologist Dr. Daniela Bota receives from her patients a cherished validation of her 12 years of groundbreaking research on glioblastoma multiforme, the most aggressive form of brain cancer. "Because of our work, these people have been able to move on with their lives," she says.

Bota has pushed the boundaries of innovation in her quest to increase the survival rates of individuals with brain tumors, especially glioblastomas. The esteemed physician-scientist has taken a truly comprehensive approach to battling this rare disease, which has a five year survival rate of only 10 percent and claimed the lives of U.S. Sens. Ted Kennedy and John McCain. Bota has conducted clinical trials of multiple cutting-edge treatments that are improving the quantity as well as the quality of life for glioblastoma patients at UCI and beyond.

'So much potential, so much growth'

Bota grew up in Romania, in a family of engineers. It was assumed she'd follow them into the profession – she was a national mathematics champion in her youth – but Bota had another path in mind. "I wanted to make a more significant contribution," she says. "I wanted to combine my analytical side with a place where I could help others. I ended up becoming an M.D.-Ph.D. to blend both."

At USC, Bota earned a doctorate in molecular biology, focusing on neural degeneration. She then went to the University of Kansas for medical school and a residency in neurology. During her shifts, Bota found herself caring for people with brain tumors – and discovered a new direction for her medical career.

The generosity and gratitude of brain tumor patients make it so rewarding to care for them. I see it again and again at UCI. Many of these patients have a terminal diagnosis, but they're volunteering their time and energy to participate in our clinical trials to help us build a better treatment and, hopefully, in the future, a cure."

Dr. Daniela Bota, UCI neuro-oncologist

After a neuro-oncology fellowship at Duke University, Bota joined the faculty of UCI's School of Medicine and the Chao Family Comprehensive Cancer Center in November 2007. "Both my career and UCI in general have grown so tremendously over the dozen years since," says Bota, who's now co-director of the UCI Health Comprehensive Brain Tumor Program. "There has been so much potential, so much growth, so many changes and so much scientific revolution helping us move forward in so many different directions. It's a very exciting time."

A comprehensive approach

The word "comprehensive" carries significant weight in the realm of cancer care centers. The "comprehensive" designation from the National Cancer Institute recognizes an added depth and breadth of research that bridges multiple scientific areas. Just 51 cancer centers in the U.S. carry the designation; the Chao Family Comprehensive Cancer Center is the only one in Orange County. "We offer one of the most innovative and complex portfolios of clinical trials anywhere in the world," Bota says.

Her own multipronged attack against glioblastoma multiforme reflects the center's comprehensive approach. Bota's work on the experimental drug marizomib has generated significant attention and hope. Unlike traditional chemotherapy drugs, marizomib can penetrate the blood-brain barrier – the filtering mechanism that prevents many blood-borne substances from passing into brain tissues – and inhibit cancer growth without causing damage to other parts of the brain.

Over the past 12 years, Bota has shepherded marizomib from preclinical development all the way through a 700-person international phase III clinical trial now underway. "We have a number of patients from our clinical trials who are surviving this tumor for longer periods of time than usually expected," she says.

Related Stories

  • Finding new clues to combat glioblastoma
  • Cancer risk in psoriatic patients
  • UCLA researcher designs ways for immune cells to 'outsmart' solid tumors

Amanda Johnson, a 32-year-old freelance writer in Mission Viejo, has been receiving marizomib for two years under Bota's care. Her large glioblastoma tumor – which straddled both sides of her brain – has shrunk so much that it's no longer measurable. She has returned to work on her novel and even joined a gym. "I feel so happy just to be alive," Johnson says.

Larry Johnson, her father, told Fox News, "I don't think [Amanda] has come to realize how important her survival is to other people and families who are going to find themselves in a similar situation."

Bota strives to reach a point where such cases will be so commonplace that they don't make the news. "That's what success looks like – not having a prominent publication or being part of a game-changing discovery," she says. "It's having patients like Amanda still be here and doing well."

Vaccine trials and right to try

To achieve that goal, Bota tenaciously pursues multiple avenues of treatment. She has been a leader in the use of Optune, a device worn on the head that generates an electrical field that disrupts the growth of cancer cells. "We were among the first in the country to explore and use this technology," Bota says. "Now we're working with physicians from other countries to help them adopt it in their practices."

She is also spearheading two clinical trials on cancer vaccines. "Brain tumors hide behind the blood-brain barrier, so the body doesn't recognize them as not being a normal part of the body," Bota explains. "With our vaccines, we extract cellular markers from the patient's tumor and inject them back into the patient to stimulate the immune system to recognize those tumors, attack them and, if possible, eliminate them."

She adds: "Both studies have been well-received in our neuro-oncological community, which is highly promising. And a significant benefit is that the vaccines function with minimal or no toxicity."

In January 2019, one of Bota's patients who was ineligible for both clinical trials was able to access one of the vaccines through the first successful application of the national Right to Try Act. Passed in May 2018, it allows people with terminal illnesses, in consultation with their doctors, to seek treatment with experimental drugs not yet approved by the Food and Drug Administration directly from pharmaceutical companies. "The law puts patients in charge of their care; they initiate contact with the manufacturer and request therapy," Bota says. "It gives patients who don't qualify for clinical trials another option."

"We offer one of the most innovative and complex portfolios of clinical trials anywhere in the world."

Sharing her expertise

Bota eagerly offers her knowledge beyond the doors of the Chao Family Comprehensive Cancer Center. Whenever she and her husband, Robert, a local psychiatrist, travel back to their home country of Romania, she consults with medical colleagues there, as there are no certified neuro-oncologists in the nation. On days when the couple work on their farm in the Transylvanian Alps, locals come to them – often on foot – for medical advice. The two hope to eventually establish a clinic in the area. "I want to make sure that Romania also benefits from my medical expertise," Bota says.

Back on campus, in her capacity as senior associate dean for clinical research, she uses her vast clinical trial experience to help colleagues in UCI's School of Medicine advance their own research projects into the clinical arena.

"I'm excited by the ability to impact the lives of so many people through this role," Bota says. "Whether it's for burns or vascular disorders or other conditions, people come to UCI for the same reason: We can offer what community hospitals cannot. Being able to make that happen, to create new options for our patients, is what wakes me up in the morning."

Source:

University of California, Irvine

The Cancer Prevention and Research Institute of Texas (CPRIT) has awarded new grants totaling $1.8 million to two University of Texas at Dallas scientists for their research related to lung and kidney cancers.

The Individual Investigator Awards are among 55 new grants totaling more than $78 million that the institute announced Feb. 19. To date, CPRIT has awarded $2.49 billion in grants to Texas research institutions and organizations through its academic research, prevention and product development research programs.

With the latest grants to the researchers in the School of Natural Sciences and Mathematics, UT Dallas has received nearly $18.5 million from CPRIT to support cancer studies.

CPRIT continues to be an important source of funding for efforts aimed at the prevention and treatment of cancer. The institute's ongoing support of basic research allows UT Dallas scientists to make important contributions toward the fundamental understanding of disease and the improvement of outcomes for cancer patients."

Dr. Joseph Pancrazio, vice president for research and professor of bioengineering at UT Dallas

Dr. Li Zhang, professor of biological sciences and the Cecil H. and Ida Green Distinguished Chair in Systems Biology Science, received $900,000 for lung cancer research. In previous studies, Zhang and her colleagues discovered that cells of the most common type of lung cancer — non-small cell lung cancer — consume substantially more oxygen than normal cells. The lung cancer cells also outpace their normal counterparts in synthesizing a critical chemical called heme, which helps transport and store oxygen. These elevated levels of oxygen and heme fuel tumor growth and progression.

With the new CPRIT grant, Zhang will use advanced imaging techniques in animal models to investigate whether drugs that target heme synthesis and uptake can be a successful strategy for suppressing lung tumors and improving the effectiveness of chemotherapy, radiotherapy and immunotherapy.

Related Stories

  • Survey: Over half of GPs, nurses who treat type 2 diabetics do not carry out annual kidney test
  • Finding new clues to combat glioblastoma
  • Targeting regulatory T cells could boost the effects of cancer immunotherapy

Zhang previously received a CPRIT grant of $900,000 in 2015.

Dr. Jie Zheng, professor of chemistry and biochemistry and the Cecil H. and Ida Green Professor in Systems Biology Science, also received $900,000 for his research, which is aimed at improving the accuracy of computerized tomography (CT)- and fluorescence-guided kidney cancer surgery.

With more kidney cancers being diagnosed in the early stage, partial kidney removal is becoming an increasingly important treatment, in particular for those patients who have poor kidney function or cancer in both kidneys. In current clinical settings, CT is used first to noninvasively localize and stage kidney cancers, followed by fluorescence imaging of normal renal tissue to guide surgery. However, due to the limitations of current contrast agents, no significant improvement in reducing positive margin rates in kidney cancer surgery has been achieved, Zheng said.

Zheng's project will focus on developing a single material, based on gold nanoparticles, that can achieve high contrast in both CT and fluorescence imaging of kidney cancers. His approach takes advantage of the unique physiological microenvironment associated with kidney cancer in a way that allows the tumor margins to be more accurately differentiated during surgical removal. His nanoparticles also have the potential to effectively and selectively deliver anti-cancer drugs to tumors that cannot be treated surgically.

Zheng received three previous CPRIT grants in 2011, 2014 and 2016 totaling nearly $2.4 million.

Source:

University of Texas at Dallas

The addition of dietary L-serine, a naturally occurring amino acid necessary for formation of proteins and nerve cells, delayed signs of amyotrophic lateral sclerosis (ALS) in an animal study.

The research also represents a significant advance in animal modeling of ALS, a debilitating neurodegenerative disease, said David A. Davis, Ph.D., lead author and research assistant professor of neurology and associate director of the Brain Endowment Bank at the University of Miami Miller School of Medicine.

The new research protocol using vervets appears more analogous to how ALS develops in humans, Dr. Davis said, compared to historic models using rodents. When he and colleagues gave the vervets a toxin produced by blue-green algae known as β-N-methylamino-L-alanine or BMAA, they developed pathology that closely resembles how ALS affects the spinal cords in humans.

When a group of these animals were fed L-serine together with BMAA for 140 days, the strategy was protective – the vervets showed significantly reduced signs of protein inclusions in spinal cord neurons and a decrease in pro-inflammatory microglia. The results were published on Thursday, February 20 at 5 a.m. EST in the prestigious Journal of Neuropathology & Experimental Neurology.

"The big message is that dietary exposure to this cyanobacterial toxin triggers ALS-type pathology, and if you include L-serine in the diet, it could slow the progression of these pathological changes," Dr. Davis said.

"I was surprised at how close the model mirrored ALS in humans," he added. Beyond looking at changes in the brain, "When we looked at the spinal cord, that was really surprising." The investigators observed changes specific to ALS seen in patients, including presence of intracellular occlusion such as TDP-43 and other protein aggregates.

Walter G. Bradley D.M., F.R.C.P., founder of the ALS Clinical and Research Center at the University of Miami Miller School of Medicine, said: "ALS is a progressive neurological disease, also known as Lou Gehrig's disease, causing progressive limb paralysis and respiratory failure. There is a great unmet need for effective therapies in this disease. After clinical trials of more than 30 potential drugs to treat ALS, we still have only two that slow the disease progression."

Related Stories

  • Healthy diet, healthier sperm, greater fertility
  • Diets high in fat and protein exacerbate C. diff infections in mice
  • As VA tests keto diet to help diabetic patients, skeptics raise red flags

ALS can rapidly progress in some people, leading to death in 6 months to 2 years after diagnosis. For this reason, it is difficult to enroll people in clinical trials, a reality that supports development of a corresponding animal model, Dr. Davis said.

In addition, prevention remains essential. "This is a pre-clinical model, which is really the most important type of model, because once people have full-blown disease, it's hard to reverse or slow its progression," he added.

The research builds on earlier findings from Dr. Davis and colleagues in a 2016 study that demonstrated cyanotoxin BMAA can cause changes in the brain that resemble Alzheimer's disease in humans, including neurofibrillary tangles and amyloid deposits.

Even with the promise of L-serine, the researchers note there is a bigger picture to their new ALS animal model. "Other drugs can also be tested, making this very valuable for clinical affirmation," Davis said.

The research also has implications for Florida, as BMAA comes from harmful blue-green algae blooms, which have become more common in the summer months in Florida.

According to Larry Brand, Ph.D., professor of marine biology at the Rosenstiel School at the University of Miami, "We have found that the BMAA from these blooms has biomagnified to high concentrations in South Florida aquatic food chains, thus our seafood."

We are very curious about how BMAA affects individuals in South Florida. That's our next step."

Dr. David A. Davis, Ph.D., lead author

Future research could attempt to answer multiple questions, including: How common is BMAA in local seafood? What are the risks of exposure through exposure to aerosolized cyanotoxins? Is there a specific group of people who are more vulnerable from this exposure to developing diseases like Alzheimer's and ALS?

The current research would not have been possible, Dr. Davis said, without interdisciplinary collaboration both inside and outside the University of Miami. Another essential factor is the "very unique research environment" in the UM Department of Neurology. For example, the Brain Endowment Bank allows Miller School researchers access to other investigators and to essential research material.

Source:

University of Miami Miller School of Medicine

Journal reference:

Davis, D.A., et al. (2020) L-Serine Reduces Spinal Cord Pathology in a Vervet Model of Preclinical ALS/MND. Journal of Neuropathology & Experimental Neurology. doi.org/10.1093/jnen/nlaa002.