TAG: "Drugs"

Discovery paves way for homebrewed drugs

UC Berkeley researchers also call for regulators, law enforcement officials to pay attention.

New research may soon make growing fields of opium poppy unnecessary when it comes to the production of opiates and potentially other drugs, such as antibiotics. A team led by UC Berkeley bioengineers has completed key steps that will enable yeast to convert sugar into pharmaceuticals.

By Sarah Yang, UC Berkeley

Fans of homebrewed beer and backyard distilleries already know how to employ yeast to convert sugar into alcohol. But a research team led by UC Berkeley bioengineers has gone much further by completing key steps needed to turn sugar-fed yeast into a microbial factory for producing morphine and potentially other drugs, including antibiotics and anti-cancer therapeutics.

Over the past decade, a handful of synthetic-biology labs have been working on replicating in microbes a complex, 15-step chemical pathway in the poppy plant to enable production of therapeutic drugs. Research teams have independently recreated different sections of the poppy’s drug pathway using E. coli or yeast, but what had been missing until now were the final steps that would allow a single organism to perform the task from start to finish.

In a new study appearing today (May 18) in the advanced online publication of the journal Nature Chemical Biology, UC Berkeley bioengineer John Dueber teamed up with microbiologist Vincent Martin at Concordia University in Montreal, to overcome that hurdle by replicating the early steps in the pathway in an engineered strain of yeast. They were able to synthesize reticuline, a compound in poppy, from tyrosine, a derivative of glucose.

“What you really want to do from a fermentation perspective is to be able to feed the yeast glucose, which is a cheap sugar source, and have the yeast do all the chemical steps required downstream to make your target therapeutic drug,” said Dueber, the study’s principal investigator and an assistant professor of bioengineering. “With our study, all the steps have been described, and it’s now a matter of linking them together and scaling up the process. It’s not a trivial challenge, but it’s doable.”

Paving the path from plants to microbes

The qualities that make the poppy plant pathway so challenging are the same ones that make it such an attractive target for research. It is complex, but it is the foundation upon which researchers can build new therapeutics. Benzylisoquinoline alkaloids, or BIAs, are the class of highly bioactive compounds found in the poppy, and that family includes some 2,500 molecules isolated from plants.

Perhaps the best-known trail in the BIA pathway is the one that leads to the opiates, such as codeine, morphine and thebaine, a precursor to oxycodone and hydrocodone. All are controlled substances. But different trails will lead to the antispasmodic papaverine or to the antibiotic precursor dihydrosanguinarine.

“Plants have slow growth cycles, so it’s hard to fully explore all the possible chemicals that can be made from the BIA pathway by genetically engineering the poppy,” said study lead author William DeLoache, a UC Berkeley Ph.D. student in bioengineering. “Moving the BIA pathway to microbes dramatically reduces the cost of drug discovery. We can easily manipulate and tune the DNA of the yeast and quickly test the results.”

The researchers found that by repurposing an enzyme from beets that is naturally used in the production of their vibrant pigments, they could coax yeast to convert tyrosine, an amino acid readily derived from glucose, into dopamine.

With help from the lab of Concordia University’s Vincent Martin, the researchers were able to reconstitute the full seven-enzyme pathway from tyrosine to reticuline in yeast.

“Getting to reticuline is critical because from there, the molecular steps that produce codeine and morphine from reticuline have already been described in yeast,” said Martin, a professor of microbial genomics and engineering. “Also, reticuline is a molecular hub in the BIA pathway. From there, we can explore many different paths to other potential drugs, not just opiates.”

Red flag for regulators

The study authors noted that the discovery dramatically speeds up the clock for when homebrewing drugs could become a reality, and they are calling for regulators and law enforcement officials to pay attention.

“We’re likely looking at a timeline of a couple of years, not a decade or more, when sugar-fed yeast could reliably produce a controlled substance,” said Dueber. “The time is now to think about policies to address this area of research. The field is moving surprisingly fast, and we need to be out in front so that we can mitigate the potential for abuse.”

In a commentary to be published in Nature and timed with the publication of this study, policy analysts call for urgent regulation of this new technology. They highlight the many benefits of this work, but they also point out that “individuals with access to the yeast strain and basic skills in fermentation would be able to grow the yeast using the equivalent of a homebrew kit.”

They recommend restricting engineered yeast strains to licensed facilities and to authorized researchers, noting that it would be difficult to detect and control the illicit transport of such strains.

While such controls may help, Dueber said, “An additional concern is that once the knowledge of how to create an opiate-producing strain is out there, anyone trained in basic molecular biology could theoretically build it.”

Another target for regulation would be the companies that synthesize and sell DNA sequences. “Restrictions are already in place for sequences tied to pathogenic organisms, like smallpox,” said DeLoache. “But maybe it’s time we also look at sequences for producing controlled substances.”

Other co-authors on this study are Zachary Russ and Andrew Gonzales of UC Berkeley’s Department of Bioengineering, and Lauren Narcross of Concordia University’s Department of Biology.

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Drug, Device, Discovery and Development initiative moves forward

UC collaborative aims to speed the discovery, development of products that improve health.

By Carole Gan, UC Davis

On April 15, more than 40 scientists from across the University of California system and representatives from the biomedical industry met to discuss plans for strengthening UC’s position in drug, device and diagnostics development.

The meeting was part of the Drug, Device, Discovery and Development (D4) initiative, a collaborative effort among UC’s five medical campuses to pool resources and expertise to accelerate the discovery and development of products that improve health.

The full day event, held in San Francisco, consisted of panel discussions and breakout sessions, with the ultimate goal of creating an efficient model for multicampus collaborations with industry partners and setting up a UC Drug Discovery Alliance. D4 has been working in tandem with the University of California Biomedical Research Acceleration, Integration & Development (UC BRAID) program to define D4’s priorities.

“We have come a long way since the inception of D4 two years ago and are now in the position to take tangible steps forward on these priorities,” said June Lee, professor of medicine and director of early translational research at UCSF. “By bringing diverse stakeholders from all of our medical campuses together with leaders from the UC Office of the President and external stakeholders, we will be able to put together and execute on an informed plan.”

Michael Rogawski, professor of neurology, leads the D4 initiative for UC Davis. Other UC Davis representatives included Dushyant Pathak, associate vice chancellor for technology management and corporate relations, and Ahmad Hakim-Elahi, executive director for research administration and director of sponsored programs.

“The opportunities that we are addressing will greatly enhance translational research across the UC system and ensure that researchers’ promising discoveries achieve their potential for clinical impact,” Rogawski said. “All of our campuses have great science and unique strengths to offer, and working together, we will have an even more profound impact on the future of drugs, devices and diagnostics.”

Connecting with industry, stimulating drug discovery

The first panel addressed how to set up a successful collaboration between several UC institutions and an industry partner and featured representatives from UCSF, UC Irvine, UC Davis, MedImmune and Quest Diagnostics.

A number of topics generated robust discussions, including how to create a mechanism for connecting industry with academic researchers, streamlining the contracting process and managing complex collaborative projects. UC BRAID already has commenced work on multicampus agreements in the realm of clinical trials, and several suggestions were explored that would allow for the comparative advantages of each BRAID campus to be more readily apparent to the biopharmaceutical industry.

The second panel discussed enabling and stimulating early drug discovery in academia and debated models for the creation of the UC Drug Discovery Alliance. Representatives from UCSF, Gladstone Institutes, Takeda Pharmaceuticals, MedImmune and the National Institutes of Health participated.

Pharmaceutical companies are increasingly looking to academic institutions to supply de-risked drug targets and candidates. However, the challenges for an academic researcher to move from basic disease-related research to the identification and development of a drug candidate are immense. The UC Drug Discovery Alliance will support UC researchers by supplying expertise in drug development, access to UC core facilities and pilot funding, and will enable the translation of many more novel therapeutics projects from the lab to patients. The creation of quality data and robust intellectual property packages for projects  also will create significant value for the UC system.

The panel identified the need for institutional support, diverse sources of funding and partnerships within the life-science ecosystem as key areas of focus. There also was lively debate around the type of organizational model the UC Drug Discovery Alliance would adopt and how to engage industry partners.

Following the panel discussions, multiple breakout sessions were held to identify high priority action items and lay out next steps. Multicampus, cross-functional workgroups will now begin work to move specific initiatives forward. Next steps for the UC Drug Discovery Alliance include selecting a focus area, initiation of partnering and fundraising activities, and creating a business plan.

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Researchers ID a potentially effective treatment for methamphetamine addiction

UCLA study finds Naltrexone may be promising treatment for addiction to methamphetamine.

A team led by Lara Ray found that Naltrexone significantly reduced people’s craving for methamphetamine, and that it made them less aroused by the drug. (Photo by Reed Hutchinson, UCLA)

By Stuart Wolpert, UCLA

A new study by UCLA researchers has found that Naltrexone, a drug used to treat alcoholism, may also be a promising treatment for addiction to methamphetamine.

“The results were about as good as you could hope for,” said Lara Ray, a UCLA associate professor of psychology, director of the UCLA Addictions Laboratory and lead author of the new study.

The study, published in the journal Neuropsychopharmacology, was the first in the U.S. to evaluate Naltrexone for treating methamphetamine addiction. Researchers analyzed 22 men and eight women who use methamphetamine an average of three to four days a week.

During a four-day hospital stay, each person was each given either Naltrexone — 25 milligrams the first two days, 50 milligrams on days three and four — or a placebo daily. Ten days later, the subjects were readmitted to the hospital for four more days; those who had taken Naltrexone earlier were given placebos, and vice versa.

On the last day of each hospital visit, all participants were given intravenous doses of methamphetamine. Three hours later, the researchers asked how they felt and how much they wanted more of the drug.

The scientists found that Naltrexone significantly reduced the subjects’ craving for methamphetamine, and that it made them less aroused by methamphetamine: Subjects’ heart rates and pulse readings both were significantly higher when they were given the placebo than when they took Naltrexone. In addition, participants taking Naltrexone had lower heart rates and pulses when they were presented with their drug paraphernalia than those who were given placebos.

Ray said the results indicated that Naltrexone reduced the rewarding effects of the drug — those taking Naltrexone did not find methamphetamine to be as pleasurable and were much less likely to want more of it.

Naltrexone was well tolerated and had very minimal side effects. The researchers found that men and women both were helped by taking Naltrexone, although the positive effect on men was slightly smaller. It made no difference whether the participants were given Naltrexone during their first hospital stay or their second.

Naltrexone works by blocking opioid receptors in the brain. Ray said that in previous studies, people undergoing treatment for alcoholism reported getting less of a “high” from drinking when they take Naltrexone.

Ray, whose research team studies the causes of drug and alcohol addiction and possible treatments, plans to examine whether Naltrexone would be more effective in combination with other pharmaceuticals and at different doses. Her research is funded by the National Institute on Drug Abuse and UCLA’s Clinical and Translational Science Institute.

Twenty-five of the participants also underwent functional magnetic resonance imaging, or fMRI, brain scans in UCLA’s Center for Cognitive Neuroscience. Ray and UCLA graduate student Kelly Courtney, a co-author of the Neuropsychoparmacology paper, are analyzing that data.

Methamphetamine use disorder is a serious psychiatric condition that can cause psychosis and brain damage, and for which no FDA-approved medication exists. An estimated 12 million Americans have used methamphetamine, nearly 400,000 of whom are addicted to it, according to recent estimates.

Although the new study is promising, it needs to be backed up by clinical trials, said Ray, who is also a member of the UCLA Brain Research Institute. The next step in evaluating Naltrexone’s effectiveness for treating people addicted to methamphetamine is already underway: the National Institute on Drug Abuse is sponsoring clinical trials.

Other UCLA co-authors of the new study include Edythe London, the Thomas P. and Katherine K. Pike Chair of Addiction Studies; Karen Miotto, a clinical professor in the department of psychiatry and biobehavioral sciences at the Semel Institute for Neuroscience and Human Behavior; Steven Shoptaw, professor in the departments of family medicine and psychiatry and biobehavioral sciences; and Keith Heinzerling, an associate professor of family medicine at the David Geffen School of Medicine.

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Drug perks up old muscles, aging brains

UC Berkeley finding could lead to drug interventions for humans.

A small-molecule drug may hold the key to fitter muscle and brain as we age. (Credit: iStock)

By Robert Sanders, UC Berkeley

Whether you’re brainy, brawny or both, you may someday benefit from a drug found to rejuvenate aging brain and muscle tissue.

Researchers at the University of California, Berkeley, have discovered that a small-molecule drug simultaneously perks up old stem cells in the brains and muscles of mice, a finding that could lead to drug interventions for humans that would make aging tissues throughout the body act young again.

“We established that you can use a single small molecule to rescue essential function in not only aged brain tissue but aged muscle,” said co-author David Schaffer, director of the Berkeley Stem Cell Center and a professor of chemical and biomolecular engineering. “That is good news, because if every tissue had a different molecular mechanism for aging, we wouldn’t be able to have a single intervention that rescues the function of multiple tissues.”

The drug interferes with the activity of a growth factor, transforming growth factor beta 1 (TGF-beta1), that Schaffer’s UC Berkeley colleague Irina Conboy showed over the past 10 years depresses the ability of various types of stem cells to renew tissue.

“Based on our earlier papers, the TGF-beta1 pathway seemed to be one of the main culprits in multi-tissue aging,” said Conboy, an associate professor of bioengineering. “That one protein, when upregulated, ages multiple stem cells in distinct organs, such as the brain, pancreas, heart and muscle. This is really the first demonstration that we can find a drug that makes the key TGF-beta1 pathway, which is elevated by aging, behave younger, thereby rejuvenating multiple organ systems.”

The UC Berkeley team reported its results in the current issue of the journal Oncotarget. Conboy and Schaffer are members of a consortium of faculty who study aging within the California Institute for Quantitative Biosciences (QB3).

Depressed stem cells lead to aging

Aging is ascribed, in part, to the failure of adult stem cells to generate replacements for damaged cells and thus repair the body’s tissues. Researchers have shown that this decreased stem cell activity is largely a result of inhibitory chemicals in the environment around the stem cell, some of them dumped there by the immune system as a result of chronic, low-level inflammation that is also a hallmark of aging.

In 2005, Conboy and her colleagues infused old mice with blood from young mice – a process called parabiosis – reinvigorating stem cells in the muscle, liver and brain/hippocampus and showing that the chemicals in young blood can actually rejuvenate the chemical environment of aging stem cells. Last year, doctors began a small trial to determine whether blood plasma from young people can help reverse brain damage in elderly Alzheimer’s patients.

Such therapies are impractical if not dangerous, however, so Conboy, Schaffer and others are trying to track down the specific chemicals that can be used safely and sustainably for maintaining the youthful environment for stem cells in many organs. One key chemical target for the multi-tissue rejuvenation is TGF-beta1, which tends to increase with age in all tissues of the body and which Conboy showed depresses stem cell activity when present at high levels.

Five years ago, Schaffer, who studies neural stem cells in the brain, teamed up with Conboy to look at TGF-beta1 activity in the hippocampus, an area of the brain important in memory and learning. Among the hallmarks of aging are a decline in learning, cognition and memory. In the new study, they showed that in old mice, the hippocampus has increased levels of TGF-beta1 similar to the levels in the bloodstream and other old tissue.

Using a viral vector that Schaffer developed for gene therapy, the team inserted genetic blockers into the brains of old mice to knock down TGF-beta1 activity, and found that hippocampal stem cells began to act more youthful, generating new nerve cells.

Drug makes old tissue cleverer

The team then injected into the blood a chemical known to block the TGF-beta1 receptor and thus reduce the effect of TGF-beta1. This small molecule, an Alk5 kinase inhibitor already undergoing trials as an anticancer agent, successfully renewed stem cell function in both brain and muscle tissue of the same old animal, potentially making it stronger and more clever, Conboy said.

“The key TGF-beta1 regulatory pathway became reset to its young signaling levels, which also reduced tissue inflammation, hence promoting a more favorable environment for stem cell signaling,” she said. “You can simultaneously improve tissue repair and maintenance repair in completely different organs, muscle and brain.”

The researchers noted that this is only a first step toward a therapy, since other biochemical cues also regulate adult stem cell activity. Schaffer and Conboy’s research groups are now collaborating on a multi-pronged approach in which modulation of two key biochemical regulators might lead to safe restoration of stem cell responses in multiple aged and pathological tissues.

“The challenge ahead is to carefully retune the various signaling pathways in the stem cell environment, using a small number of chemicals, so that we end up recalibrating the environment to be youth-like,” Conboy said. “Dosage is going to be the key to rejuvenating the stem cell environment.”

Other co-authors of the paper are former graduate student Hanadie Yousef, now at Stanford University; and Michael Conboy, Adam Morgenthaler, Christina Schlesinger, Lukasz Bugaj, Preeti Paliwal and Christopher Greer of UC Berkeley’s bioengineering department and QB3.

The work was supported by grants from the National Institutes of Health, California Institute for Regenerative Medicine and a Rogers Family Foundation Bridging-the-Gap Award.

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New combination treatment strategy to ‘checkmate’ brain tumors

Three different classes of anti-cancer drugs work synergistically against brain tumors.

Normal cell dividing (left) and stressed cancer cell dividing (right). PLK1 inhibitors stress cancer cells, making them easier to kill.

By Heather Buschman, UC San Diego

Therapies that specifically target mutations in a person’s cancer have been much-heralded in recent years, yet cancer cells often find a way around them. To address this, researchers at the UC San Diego School of Medicine and Moores Cancer Center identified a promising combinatorial approach to treating glioblastomas, the most common form of primary brain cancer.

The study, published May 5 by Oncotarget, demonstrates that a mouse model of glioblastoma and human glioblastoma tissue removed from patients and cultured in the lab can be effectively treated by combining three classes of anti-cancer drugs: a drug that targets a cancer mutation in the Epidermal Growth Factor Receptor (EGFR) gene, a drug that increases stress in cancer cells and a drug that damages cancer cell DNA.

“Developing therapies against glioblastoma is like a chess game. For each therapy administered, or move, by the physician, the cancer makes a counter-move,” said senior author Clark Chen, M.D., Ph.D., associate professor of neurosurgery and vice chair of research and academic development at UC San Diego.

In up to 50 percent of glioblastomas, mutations in the EGFR gene render cancer cells insensitive to growth regulation by environmental cues, allowing them to grow uncontrollably. Yet highly specific EGFR inhibitors are not particularly effective against glioblastomas with EGFR mutations.

“When glioblastoma cells are treated with EGFR inhibitors, they turn on another receptor to bypass the need for EGFR,” said Chen. “Any hope of an effective treatment requires a combination of moves strategically designed for a checkmate.”

To develop such a strategy, Chen and his group turned to PLK1, a protein that regulates stress levels within glioblastoma cells and is essential for their survival. Chen and his group found that glioblastoma cells that developed resistance to EGFR inhibitors remain universally dependent on this protein.

In mouse models of glioblastoma and in explants of human glioblastoma, singular treatment with an EGFR inhibitor, a PLK1 inhibitor or the current standard of care drug (a DNA-damaging agent), each temporarily halted glioblastoma growth. But, like the human disease, the tumor eventually grew back. However, no detectable tumor recurrence was observed when a combination of all three classes of drugs was administered. The treated mice tolerated this combination regimen without showing significant side effects.

“It is often assumed that if we find the cancer-causing mutation and inhibit the function of that mutation, we will be able to cure cancer,” said study co-author Bob S. Carter, M.D., Ph.D., chief of neurosurgery at UC San Diego. “Our study demonstrates that the reality is far more complex. Our results provide a blueprint for how to leverage fundamental biologic concepts to tackle this challenging complexity.”

The three drugs administered to mice in this study were: BI2536, a PLK1 inhibitor; Gefitnib, an EGFR inhibitor; and TMZ, the standard-of-care chemotherapy for glioblastoma. The study authors note that while the safety or side effects of treating human patients will all three drugs is unknown, all are individually well-tolerated in humans. The clinical safety profiles of Gefitinib and TMZ are well-established for glioblastoma patients and PLK1 inhibitors have so far been well-tolerated in clinical trials (one has advanced to phase three clinical trials for acute myeloid leukemia).

Co-authors of this study include Ying Shen, UC San Diego and Shanghai Jiao Tong University; Jie Li, Diahnn Futalan, Tyler Steed, Jeffrey M Treiber, and Zack Taich, UC San Diego; Masayuki Nitta, Dana-Farber Cancer Institute; Deanna Stevens, Jill Wykosky, Frank B. Furnari, Webster K. Cavenee, and Arshad Desai, UC San Diego and Ludwig Cancer Research; Hong-Zhuan Chen, Shanghai Jiao Tong University; Oren J. Becher, Duke University Medical Center; Richard Kennedy, Queen’s University of Belfast; Fumiko Esashi, University of Oxford; and Jann N. Sarkaria, Mayo Clinic.

This research was funded, in part, by the Sontag Foundation, Burroughs Wellcome Foundation, Kimmel Foundation, Doris Duke Foundation and Forbeck Foundation.

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Molecular homing beacon redirects human antibodies to fight pathogenic bacteria

Bacteria-specific molecules attract antibodies to help immune system clear infection.

Alphamers (purple) act as homing beacons, attracting pre-existing anti-alpha-Gal antibodies (green) to the bacterial surface. Watch the full animation at https://youtu.be/5cfxhu3YqGs. (Credit: Altermune Technologies)

By Heather Buschman, UC San Diego

With the threat of multidrug-resistant bacterial pathogens growing, new ideas to treat infections are sorely needed. Researchers at the UC San Diego School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences report preliminary success testing an entirely novel approach — tagging bacteria with a molecular “homing beacon” that attracts pre-existing antibodies to attack the pathogens. The study is published by the Journal of Molecular Medicine.

The molecular homing beacon is the brainchild of study co-author and Nobel laureate Kary Mullis, Ph.D., who invented polymerase chain reaction (PCR), a now-common lab technique used to replicate DNA.

One end of the homing beacon is made up of a DNA aptamer, a small piece of DNA that can be selected from a pool of billions of candidates based on its ability to bind tightly to a particular target. In this test case, the aptamer specifically targeted group A Streptococcus, the bacteria that causes strep throat and invasive skin infections, while leaving human cells untouched. The other end of the homing beacon is alpha-Gal, a type of sugar molecule. Humans naturally produce antibodies against alpha-Gal. That’s because alpha-Gal is foreign to humans. Other mammals and some microbes produce it. Humans have evolved antibodies against it when we eat meat or are exposed to alpha-Gal-generating microbes in our environment.

To test the homing beacon — or “Alphamer” — against live strep bacteria, Mullis enlisted the help of Victor Nizet, M.D., professor of pediatrics and pharmacy at UC San Diego, whose laboratory studies how pathogens interact with the human immune system. The research team found that Alphamers not only bind strep and recruit anti-Gal antibodies to the bacterial surface, they also helps human immune cells engulf and kill the Alphamer-coated bacteria.

The study offers the first proof-of-concept that Alphamers have the potential to specifically redirect pre-existing antibodies to bacteria and rapidly activate an antibacterial immune response.

“Our next step is to test Alphamers in animal models of infection with multidrug-resistant bacteria that pose a public health threat, such as MRSA,” said first author Sascha Kristian, Ph.D., visiting research scholar at UC San Diego and ‎associate research director at Altermune Technologies, a company Mullis founded to develop Alphamers into unique therapeutics. “Meanwhile, we’ll also be tweaking the Alphamer to make it more potent and more resistant to degradation by the body.”

If Alphamers continue to show promise, researchers might be able to apply the same concept to attack any type of bacteria or virus, or perhaps even cancer cells.

“We’re picturing a future in which doctors have a case full of pathogen-specific Alphamers at their disposal,” Nizet said. “They see an infected patient, identify the causative bacteria and pull out the appropriate Alphamer to instantly enlist the support of the immune system in curing the infection.”

An animation of the Alphamer technology is available at: https://youtu.be/5cfxhu3YqGs.

Co-authors of this study include John H. Hwang, and Emma Leire, UC San Diego; Bradley Hall, and Kary B. Mullis, Altermune Technologies; John Iacomini, Tufts University School of Medicine; Robert Old, Loxbridge Research; Uri Galili, University of Massachusetts Medical School; Charles Roberts, and Mike Westby, Altermune Technologies and Loxbridge Research.

This research was funded by Altermune Technologies LLC (Irvine).

Disclosure: Victor Nizet is a member of the Scientific Advisory Board for Altermune Technologies LLC.

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Boosting the body’s natural ability to fight urinary tract infections

Drug that stabilizes immune defense protein HIF-1alpha protects vs. major UTI pathogen.

By Heather Buschman, UC San Diego

Urinary tract infections (UTIs) are common, and widespread antibiotic resistance has led to urgent calls for new ways to combat them. Researchers at the UC San Diego School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences report that an experimental drug that stabilizes a protein called HIF-1alpha protects human bladder cells and mice against a major UTI pathogen. The drug might eventually provide a therapeutic alternative or complement to standard antibiotic treatment.

The study is published today (April 30) by PLOS Pathogens.

HIF-1alpha is known to influence the innate immune response, the body’s first line of defense against intruding pathogens. Like many regulator proteins, HIF-1alpha is relatively short-lived. To increase HIF-1alpha levels, researchers have developed drugs that delay its breakdown. This same pathway has been the target for drugs now in advanced clinical trials for treatment of anemia.

In this study, Victor Nizet, M.D., professor of pediatrics and pharmacy, and colleagues explored the use of HIF-1alpha-stabilizing drugs to boost the innate immune response to uropathogenic E.coli (UPEC) bacteria, a major cause of UTIs. In healthy human urinary tract cells, treatment with the drugs increased HIF-1alpha levels. Such cells were then more resistant to UPEC attachment, invasion and killing than human urinary tract cells with normal HIF-1alpha levels.

Using a mouse model of UTI, the researchers showed that administration of HIF-1alpha stabilizers directly into the bladder protected against UPEC infection. They also found that invasion of bladder cells, a critical early step in the infection process, was reduced in treated mice compared to untreated mice.

To verify the importance of HIF-1alpha in the defense against UPEC infection, the researchers studied mice with reduced HIF-1alpha levels. Exposed to UPEC, these mice were more susceptible to bladder infection, and pre-treatment with HIF-1alpha stabilizers made no difference. This demonstrates that the drugs combat UTIs through their effect on HIF-1alpha.

Finally, the researchers examined whether treatment with HIF-1alpha stabilizers would be beneficial against an established UTI. To do this, they infected mice with UPEC first and then administered the drugs into the bladder six hours later. The treated mice had a more than 10-fold reduction in bladder colonization with the bacteria, demonstrating that HIF-1alpha stabilization is beneficial even after the initial infection.

“The ultimate goal of this research will be to advance HIF-1alpha stabilizers toward clinical trials in humans, using versions of the drug that can be taken orally and reach the urinary tract,” Nizet said.

Co-authors include Ann E. Lin, Federico C. Beasley, Joshua Olson, and Nadia Keller, UC San Diego; Robert A. Shalwitz, Aerpio Therapeutics; Thomas J. Hannan, and Scott J. Hultgren, Washington University.

This research was funded, in part, by the National Institutes of Health (grants AI093451, AI057153, AI048689, HD071600 and DK098870), Canadian Institute of Health Research and American Association of Anatomists.

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Drug that can prevent onset of diabetes is rarely used

Metformin is inexpensive, effective for people with pre-diabetes, but few take it.

Tannaz Moin, UCLA

By Enrique Rivero, UCLA

Few doctors are prescribing a low-cost drug that has been proven effective in preventing the onset of diabetes, according to a UCLA study. The study, published in the peer-reviewed journal Annals of Internal Medicine, found that only 3.7 percent of U.S. adults with pre-diabetes were prescribed metformin during a recent three-year period.

Metformin and lifestyle changes both can prevent the onset of diabetes, but people often struggle to adopt healthier habits, according to Dr. Tannaz Moin, the study’s lead author and an assistant professor of medicine in the division of endocrinology at the David Geffen School of Medicine at UCLA and at VA Greater Los Angeles.

“Diabetes is prevalent, but pre-diabetes is even more prevalent and we have evidence-based therapies like metformin that are very safe and that work,” Moin said. “Metformin is rarely being used for diabetes prevention among people at risk for developing it. This is something that patients and doctors need to be talking about and thinking about.”

It is estimated that about one-third of adults in the U.S. have pre-diabetes, which is marked by higher-than-normal blood sugar levels.

The American Diabetes Association in 2008 added metformin to its annual “Standards for Medical Care in Diabetes” guidelines for use in diabetes prevention for those at very high risk who are under age 60, are severely obese, or have a history of gestational diabetes. Under the guidelines, metformin may also be considered for patients whose blood sugar is above normal but not yet in the diabetes range.

The researchers examined data from 2010 to 2012 from UnitedHealthcare, the nation’s largest private insurer, for a national sample of 17,352 adults aged 19 to 58 with pre-diabetes. They also found:

  • The prevalence of metformin prescriptions was 7.8 percent for severely obese patients.
  • Metformin prescriptions were nearly twice as high for women (4.8 percent) as for men (2.8 percent).
  • Among people with pre-diabetes, the prevalence of prescriptions for obese individuals was 6.6 percent, versus 3.5 percent for non-obese people.
  • Among people who had pre-diabetes and two other chronic diseases, 4.2 percent received prescriptions for metformin, versus 2.8 percent of people with pre-diabetes and no other chronic diseases.

The reasons for the underuse of metformin are not clear, the researchers write, but they could include a lack of knowledge of the 2002 Diabetes Prevention Program Study, which showed that both lifestyle changes and metformin use can prevent or delay progression to diabetes among those with pre-diabetes, the fact that the drug does not have FDA approval for pre-diabetes and reluctance by patients and doctors to “medicalize” pre-diabetes.

“Identifying more effective ways to help people avoid diabetes is essential to individuals’ lives and to society as a whole, which is why it was important to us to support this research,” said Dr. Sam Ho, a co-author of the study and chief medical officer of Minnetonka, Minnesota-based UnitedHealthcare.

Potential limitations to the study included a lack of access to data on participation in lifestyle programs; possible misclassification of pre-diabetes and metformin use; the fact that the analysis focused on adults with commercial insurance, which could make the findings inapplicable to uninsured or older adults; and the researchers’ inability to independently verify patients’ eligibility to receive metformin under the American Diabetes Association guidelines.

The study’s co-authors are Jinnan Li, O. Kenrik Duru, Susan Ettner, Norman Turk and Carol Mangione of UCLA; and Abigail Keckhafer of UnitedHealthcare.

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Novel approach blocks amyloid production in Alzheimer’s mouse model

Promises potential early therapeutic intervention.

By Scott LaFee, UC San Diego

Offering a potential early intervention for Alzheimer’s disease (AD), researchers at UC San Diego School of Medicine and Cenna Biosciences Inc. have identified compounds that block the production of beta amyloid peptides in mice. The study is reported today (April 29) in PLOS ONE.

If the results ultimately translate to human treatment, the most promising compound – a peptide dubbed P8 – could be administered to individuals at high risk of developing the disease, long before the tell-tale signs of dementia occur and perhaps with few side effects, due to the compound’s highly specific mode of action.

“Our approach is completely different from any current approaches that target beta amyloid,” said lead author Nazneen Dewji, Ph.D., associate adjunct professor in the Department of Medicine. “We are blocking the actual production of beta amyloid in a new way. It’s very promising because it means that, in principle, we can stop the disease in its tracks.”

The build-up of beta amyloid plaques is widely believed to cause irreversible brain damage, resulting in a host of cognitive and motor impairments broadly associated with AD, which accounts for about 60 to 80 percent of all cases of dementia in the United States.

Because of the currently perceived role of beta amyloid in disease progression, several investigational drugs have targeted the enzymes that cleave beta amyloid from its larger precursor protein, the aptly named amyloid precursor protein (APP).

“These drugs, however, have largely failed in clinical trials,” said Dewji, “mostly because they are responsible for cleaving other proteins besides APP. Inhibiting or modifying their activities creates many undesirable effects in the cell.”

The P8 compound does not act on enzymes, but rather binds to APP and in so doing, prevents the larger protein from being processed into smaller amyloid peptides. The compounds are derived from a fragment of a membrane protein known as presenilin 1 that is known to interact with APP to produce beta amyloid. The highly specific binding between the APP and P8 was measured using both biophysical methods and optical imaging techniques.

“Our approach is different, specific and interferes with only the reaction that produces beta amyloid, as opposed to drugs that target the enzymes responsible for its cleavage from APP, which can affect multiple reactions in cells,” said Dewji, who is also president and CEO of the La Jolla-based biopharmaceutical company Cenna, where the drug candidates are being developed.

In addition to cell culture experiments, researchers also conducted experiments with mice, engineered to produce large amounts of the human beta amyloid early in life.

Their experiments showed that a two-week course of treatment with either P8 or another compound called P4 resulted in, on average, a greater than 50 percent reduction in plaque accumulation, as compared with mice who received no treatment.

“We now have a new approach for the treatment of Alzheimer’s disease that can arrest the production of beta amyloid very early and specifically,” she said. “It’s a real chance at a successful treatment for Alzheimer’s disease.”

Other co-authors include Eliezer Masliah, Edward Rockenstein, Martha Harber, and Taylor Horwood, UC San Diego; and Mihyun Kim, UC San Diego and Cenna Biosciences.

Funding for the study came, in part, from National Institutes of Health (grants 5RO1NS055161, 5RO1AG17888 and 1R43AG043278) and Alzheimer’s Drug Discovery Foundation.

Disclosure: Dewji and co-author S. Jonathan Singer, Ph.D., professor emeritus in the Division of Biological Sciences, founded Cenna in 2006. The technology that forms the basis of Cenna’s approach and lead compounds is covered by U.S. and foreign patent applications filed by UC San Diego and exclusively licensed to Cenna. 

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Combined chemotherapy, immunotherapy shows promise for prostate cancer

Achieves near complete remission in mouse models of advanced prostate cancer.

By Heather Buschman, UC San Diego

Chemotherapy can be very effective against small prostate tumors. Larger prostate tumors, however, accumulate cells that suppress the body’s immune response, allowing the cancer to grow despite treatment. Researchers at the UC San Diego School of Medicine now find that blocking or removing these immune-suppressing cells allows a special type of chemotherapy — and the immune cells it activates — to destroy prostate tumors. This novel combination therapy, termed chemoimmunotherapy, achieved near complete remission in mouse models of advanced prostate cancer.

The study is published today (April 29) in Nature.

Advanced or metastatic prostate cancer does not typically respond to chemotherapy. Prostate cancers also fail to respond to a promising new type of immunotherapy drugs, called checkpoint inhibitors, which disable cancer cells’ cloaking mechanism so that a person’s own immune system can better fight the tumor. This specific resistance is likely due in part to immunosuppressive B cells, which are more common in larger prostate tumors in mice, as well as in advanced and metastatic prostate cancer in humans. As the name suggests, these cells keep the immune system at bay, rendering most therapies ineffective and allowing malignant tumors to grow unchecked.

In this study, researchers worked with three different mouse models of advanced prostate cancer. All three models were resistant to low doses of the chemotherapy drug oxaliplatin, which has the unique ability to activate cancer-killing immune cells. But when the researchers blocked the development or function of immunosuppressive B cells or removed them entirely before treating the mice with low-dose oxaliplatin, the prostate tumors were almost completely destroyed by the mice’s own immune cells. The team got similar results when low-dose oxaliplatin was combined with a checkpoint inhibitor.

“The presence of such B cells in human prostate cancer calls for clinical testing of this novel therapeutic approach,” said Shabnam Shalapour, Ph.D., postdoctoral researcher and first author of the study.

Prostate cancer is the second leading cause of cancer-related death in American men. About one in seven men will be diagnosed with prostate cancer during their lifetimes.

“In addition to prostate cancer, similar immunosuppressive B cells can be detected in other human cancers,” said senior author Michael Karin, Ph.D., Distinguished Professor of Pharmacology and Pathology at UC San Diego. “This indicates that B cell-mediated immunosuppression might be the reason several other cancers are also unresponsive to checkpoint inhibitors, raising the hope that chemoimmunotherapy will have broader applications for many cancer types.”

Study co-authors include Joan Font-Burgada, Giuseppe Di Caro, Zhenyu Zhong, Elsa Sanchez-Lopez, Debanjan Dhar, Massimo Ammirante, Amy Strasner, Donna E. Hansel, Christina Jamieson, and Christopher J. Kane, UC San Diego; Gerald Willimsky, Charite-Medical University of Berlin; Tobias Klatte, Peter Birner, and Lukas Kenner, Medical University of Vienna.

This research was funded, in part, by the National Institutes of Health (grants CA127923 and AI043477), California Institute for Regenerative Medicine, German Research Foundation, Genome Research-Austria and Cancer Research Institute.

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Can ‘intelligent design’ deliver?

UC Berkeley bioengineer David Schaffer harnesses evolution to improve drug delivery.

David Schaffer, UC Berkeley (Photo by Peg Skorpinski, UC Berkeley)

By Wallace Ravven

What do Washington lobbyists and gene therapy have in common? Success for both depends on access and influence.

By and large, most drugs are “small molecules,” able to find their way to targets between cells or inside specific cells. They can provide relief from acid reflux, infection or inflammation, or keep serious conditions like diabetes and cardiovascular disease under control. But they demand refill after refill. They aren’t cures.

Serious genetic diseases also require a lifetime of treatment. Bronchodilators and inhaled antibiotics treat severe congestion and lung infections that often shorten the lives of people with cystic fibrosis. Penicillin, blood transfusions and even bone marrow transplants treat sickle cell anemia. A single gene defect causes both conditions.

If the normal gene could somehow replace the functions of the abnormal one in affected cells and tissues, the diseases would be cured. This, of course, is the high ambition of gene therapy.  For more than 25 years, researchers have tried the savvy-sounding approach of delivering corrective genes to affected cells by ferrying them inside benign human viruses. Viruses know the territory intimately, so why not piggy back on a proven vehicle?

But, says UC Berkeley bioengineer David Schaffer,  “There’s an old joke about gene therapy. ‘The are only three problems in the field: delivery, delivery, delivery.’”

The strategy has run up against a powerful force: evolution. Viruses and the human immune system are locked in a timeless arm’s race. The invader hones its skills, and our immune systems develop antibodies and other defenses to neutralize any innovations. The more persistent the pathogen, the more likely our immune system has encountered it before and has developed antibodies to protect against it.

“We’re fighting biology and evolution,” Schaffer says. The viruses must also reach the right cell type among many within a tissue, and in sufficient numbers to deliver its gene cargo. The challenges have stalled gene therapy from its outset.

Schaffer, director of the Berkeley Stem Cell Center, is a professor of chemical and biomolecular engineering. He was named one of the “Top 100 Innovators under 35” by Technology Review magazine in 2002 for his early efforts to actually use  evolution to overcome the hurdles of viral gene delivery. Clean-cut in a checkered shirt, he still looks to be that same young bioengineer. And he has kept his focus on delivering gene therapy.

Rather than trying to quiet the body’s defenses against viruses, Schaffer has favored a kind of intelligent design approach to modify the virus. Known as directed evolution, the strategy uses genetic engineering to find variations in the virus that will allow it to effectively deliver drugs to target cells.

His lab works with a common, harmless human respiratory adeno-associated virus, or AAV. More than 90 percent of the human population has been infected by this virus, so it’s got a proven track record for invasion, which our immune systems remember. Schaffer spurs the virus’s evolution in search of a variant that can overcome the immune and tissue defenses.

Our bodies pose many barriers to viral infection, including immune system recognition of the virus’s outer shell, or capsid. In the 1980s researchers discovered that natural variations of a 740-amino-acid-long protein self-assemble to make the AAV capsid.  Schaffer’s lab used genetic engineering to shuffle and mutagenize the amino acid sequences and generate “libraries” of millions of variants of the capsid protein.

The team then screened the millions of variants, selecting for the few that could best elude human antibodies, home to the  right tissues, and make their way to chosen target cells. The result of this directed evolution: a vehicle that can deliver healthy genes to defective cells.

Last year, he and UC Berkeley colleague John Flannery showed that the virus could deliver curative genes to eye cells to cure several blinding diseases in mouse models. The results show promise for a new way to treat disorders from the inherited defects of retinitis pigmentosa to age-related macular degeneration.

“We’ve created a virus that can deliver genes to a very-difficult-to-reach population of delicate cells in a way that is surgically non-invasive and safe,” Schaffer said at the time. Their success was published in the journal Science Translational Medicine.

His lab also applies the directed evolution strategy to stem cell gene therapy. He and colleagues recently reported using directed evolution of the AAV virus to deliver potentially curative genes to human pluripotent stem cells. “There are many diseases that can be cured by treating stem cells” he says.

The stem cell research field is still young, and the Berkeley Stem Cell Center encourages collaborations between investigators who examine fundamental stem cell properties and bioengineers such as Schaffer who aim to harness the new knowledge.

His success with directed evolution led him and colleagues to launch a startup last year, called 4D Molecular Therapeutics. They are now working with uniQure, the only company that has a clinically approved gene therapy product. uniQure intends to put 4D’s next generation, evolved viruses  into their clinical pipeline.

“The campus really recognizes that translating our research to clinical use is central to its mission to have an impact on society. It’s also a potential source of funds for the campus,” he says.  Schaffer sees gene therapy starting out on a track to treat relatively rare diseases for which no other therapies exist. Ultimately though, with effective delivery systems, gene therapy could find its way to treat common diseases involving faulty proteins, such as macular degeneration, diabetes, and heart disease, he says.

That, of course, is well down the line, but Schaffer can see it: “Medicine in the future may involve intelligent viruses that with a single injection can cure a host of diseases.”

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Immunotherapy drug shows success in treating advanced lung cancer

UCLA researchers say study also will help ID which people could respond best to treatment.

Edward Garon, UCLA

By Reggie Kumar, UCLA

In what is thought to be the largest study to date using immunotherapy to treat lung cancer, UCLA researchers have found that the drug pembrolizumab (Keytruda), recently approved by the U.S. Food and Drug Administration to treat some melanoma patients, is safe and effective in arresting tumor growth in people with advanced non-small cell lung cancer.

Approximately 25 percent of patients’ tumors had high levels of the protein PD-L1, and the study found that they were the people most likely to have the best outcomes. The research was the first validation of PD-L1 expression as a marker of how patients will respond to the drug.

“These results have the potential to substantively change the way that lung cancer is treated,” said Dr. Edward Garon, a member of UCLA’s Jonsson Comprehensive Cancer Center and lead author of the study. “The effectiveness of pembrolizumab in treating patients with non-small cell lung cancer and the prolonged duration of their responses is quite exciting.”

The study was published online in the New England Journal of Medicine April 19, coinciding with a presentation of the findings by Garon at the American Association for Cancer Research annual meeting.

Pembrolizumab is an antibody that targets a protein expressed by immune cells called PD-1. In the body, PD-1 acts as an immune checkpoint inhibitor, turning down the immune system’s T cells that otherwise could attack cancer cells as invaders. Pembrolizumab takes the brakes off the immune system and allows T cells to identify and attack cancer cells.

The FDA granted “breakthrough therapy” designation to pembrolizumab for non-small cell lung cancer in October 2014 under its Accelerated Approval program. Last September, the drug was approved by the FDA to treat people with late-stage melanoma.

The nearly three-year clinical trial involved 495 participants, including nearly 100 at UCLA. The overall response rate — the percentage of people in whom tumors were substantially reduced in size — was 19 percent, and the average duration of response in those who responded exceeded one year, regardless of the level of PD-L1 expression.

In addition, less than 10 percent of patients experienced severe (grade 3 or greater) drug-related adverse events, a rate much lower than what is typically seen with traditional chemotherapies.

Approximately one-quarter of those screened in the trial had PD-L1 expression in at least half of their tumor cells. Among them, the overall response rate was nearly 50 percent. Although previous data suggested that clinical outcomes with this class of drugs could be associated with the level of PD-L1 expression, this study was the first to validate this finding in a scientifically rigorous way.

The median duration of survival in the high PD-L1 expression group of patients could not be reported because most of the patients are still alive.

“Although we continue working to refine our selection of patients for this type of therapy, the identification of a population of patients who are likely to have such a good outcome is potentially game-changing for this group,” said Garon, who also co-authored a study on tumor mutations and immunotherapy that was published this month in the journal Science. That research aimed to further refine patient selection factors.

Lung cancer is now the leading cause of death worldwide, and the American Lung Association estimates that more than 158,000 in the U.S. will die from the disease this year alone. Garon said he hopes that the findings will encourage the FDA to approve Keytruda for the treatment of non-small cell lung cancer in those people who are most likely to benefit.

“Neither the drug nor the PD-L1 biomarker test is approved for use at this time, but if I had a patient whose tumor had PD-L1 expression in at least half of their cancer cells and pembrolizumab was available, I would find the drug to be a compelling treatment option for the patient,” Garon said.

One survivor’s story

Stephen Burrin, now 71, was always health conscious and an avid runner. After he was first diagnosed with throat cancer, in 2002, he underwent surgery to remove the tumor and had extensive chemotherapy and radiation treatments. Fortunately, the treatment was a success, and Burrin was cured.

But eight years later, Burrin suffered a series of devastating diagnoses. Doctors initially discovered a new cancerous tumor that was so large it nearly filled the two upper lobes of his lungs. The following year, two additional tumors were found in the right lower lobe of his lung and in his thigh. Finally, in 2012, a CT scan revealed more than 20 additional tumors in both lower lobes of the lungs.

Instead of opting for more chemotherapy and surgery, Burrin decided to get a second opinion at UCLA, where he met with Dr. Jonathan Goldman, a member of the Jonsson Cancer Center and co-author of the New England Journal research. Goldman told Burrin about the recent success of pembrolizumab to treat melanoma, and explained that Garon’s clinical trial was open to lung cancer patients.

Burrin enrolled in the trial and, after he took pembrolizumab for several months, his tumor volume was substantially reduced.

“It’s a miracle I’m alive,” Burrin said. “This immunotherapy has been unbelievably successful for me, and the side effects have been very minor.”

The drug has continued to prevent Burrin’s cancer from worsening. He has been able to renew his passion for running, and in October he completed the Manhattan Beach 10K Run. He also has been able to realize two other meaningful milestones: holding his newborn grandson and celebrating his 40th wedding anniversary in Hawaii.

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