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Viruses: Our Worst Enemies
or Best Friends?
by Maryann Brinley

The baby is cranky. She caught something. He could be teething. No big deal.

When a young child comes down with a mild fever, a slightly runny nose or a touch of diarrhea, parents often take it for granted, especially if symptoms don’t get worse. Such minuscule turns in health come with the territory of growing up and a growing immune system.

The same reovirus which infects children between the ages of 6 and 24 months, causing mild cold symptoms, is also being tested as a weapon in the war on cancer.

What virologists like Aaron Shatkin, PhD, Director of the Center for Advanced Biotechnology and Medicine (CABM), understand is that these symptoms may be signs of a reovirus. This is a mild-mannered virus Shatkin knows well because as a young researcher at the National Institutes of Health (NIH), he studied its genome (only 10 genes) and identified an important sequence of reactions through which it takes over a cell. Viruses, in fact, can’t even be considered alive until they invade the cells of a plant, animal or human. However, once past the cell’s outside layer (envelope) and happily set up inside, they can — and some do — multiply wildly. “I can remember one of those moments of discovery.

Herpes, or human cytomegalovirus (HCMV), is one of the largest and most complicated viruses, especially in terms of genomic organization. In breakthrough technology, Hua Zhu's NJMS lab took the entire genome out of this virus and put it into E. coli bacteria where it replicates on its own. Zhu says, "The biggest advantage of this is that we can use powerful bacterial genetics to engineer the HCMV genome quickly and efficiently, take the HCMV's DNA out, and put it back into human cells to generate recombinant viruses." Pictured here in its green viral plaque state is one of Zhu's artificially constructed HCMV bacterial chromosomes.

I knew the reovirus made more of itself but not how it was done,” recalls Shatkin, professor of molecular genetics, microbiology and immunology at UMDNJ-Robert Wood Johnson Medical School (RWJMS). “I recall standing there in the lab counting my sample for a few minutes and soon, it was, Eureka! Wow! Then, of course, like all scientists, I started worrying if I had assayed the right sample. But I was right and as it turned out, this double-stranded RNA virus, and many other viruses, have their own enzymes for replicating. I demonstrated how viruses used them and cellular components to reproduce.” For his lifetime of work revealing how viruses spread within cells, Shatkin was given the 2003 Award for Distinguished Research in Biomedical Sciences by the Association of American Medical Colleges.

This reovirus, which infects children between ages 6 and 24 months, provides a perfect example of the double-edged power of viruses. Are they among our worst enemies? Could they also be our next best friends?

As dozens of UMDNJ researchers are discovering in the quest to unlock the mysteries of viruses, these tiny, enigmatic parasites possess both negative and positive qualities. After all, vaccines — which protect us from everything from hepatitis, smallpox, measles, mumps, chickenpox and the ever-mutating strains of the flu — are actually pieces of viruses reformulated to stimulate the immune system so the body will fend off later attacks by the same virus. Virotherapy — using viruses to harness the immune system — is not exactly a new concept. Doctors have treated lots of cancer patients with wild type viruses in the last century but with limited success. However, with some genetic engineering, viruses are becoming powerful new defense systems in medicine. Reoviruses, for instance, are so wily that they can be forced to take advantage of an activated genetic pathway (Ras) into cancer cells found in brain, prostate, breast, ovarian, pancreatic and colorectal tumors. Once inside, theoretically, the reovirus can infect and kill off the cancer without destroying neighboring tissue or the host itself.

Aaron Shatkin, PhD, CABM director, is a pioneering virologist whose work with the reovirus demonstrated how viruses spread within cells. He says, “I can remember one of these moments of discovery in the lab. As it turned out, this double-stranded RNA virus and many other related viruses in its reoviridae family have their own enzyme for replicating.”

So small that 10 million sitting side by side won’t cover the period at the end of this sentence, viruses cause infections, all kinds of diseases, and even cancer. Naturally, they are considered our enemies. The very definition of a virus comes from the Latin for “slimy liquid, poison, stench.” In war, they turn up as bioweapons. Even in peace, a common influenza virus can quickly fall into mass murderer category because it kills about 36,000 people per year in the U.S., according to the Centers for Disease Control and Prevention (CDC). Larry Budnick, MD, MPH, associate professor of medicine at New Jersey Medical School (NJMS), explains, “The flu virus is complicated because it changes or drifts a little every year and sometimes it shifts, or changes a lot. In most seasons, there are actually three different types of flu virus circulating. This past year, the predominant one was Fujian, named for where it was first isolated.” Fears of a lethal avian flu which emerged in Asia in the winter have had international virus hunters on edge. This bird strain stays alive in frozen materials indefinitely and thrives in water up to 72 degrees Fahrenheit.

Interferon-stimulated genes (ISGs) include a large number of genes whose expression is normally turned on by interferons (a biotherapeutic agent). Generally, all the genes in this ISG family are activated by a special signal transduction pathway and this image, produced by NJMS virologist Hua Zhu, shows one of them, MxA, activated (in green). The nuclei are in blue and the bits of red indicate the immediate-early antigen of herpes, or HCMV-infected cells. "Surprisingly, we found that HCMV turned on this signal transduction pathway by itself. We have also shown that if this pathway is blocked, chemically or genetically, viral production of herpes is dramatically reduced." Reports of this work will appear in an upcoming issue of the Journal of Virology.

Victor Stollar, MD, RWJMS professor of molecular genetics, microbiology and immunology, whose lab has been studying the mosquito-transmitted Sindbis virus, explains, “Beginning in the 1950s, our knowledge of viruses exploded as we learned what they look like, what they are composed of and how they replicate.” Research tools such as X-ray crystallography now show the infinitesimal structures of various viruses to be as complex and three-dimensional as a cast of characters in a science fiction movie. Picture tightly coiled spirals, icosahedrons (a shape with 20 triangular faces and 12 points), and miniature characters with heads and helical tails or rodlike filaments jutting out from square-ish surfaces. Stollar says that there are approximately 1550 virus species in 56 viral families but adds, “We only come across viruses when they cause some problem in humans, animals or plants so we may be seeing just a small fraction of them.” His own lab discovered a new virus in the “Flavi” family, a nasty group known for encephalitis, yellow fever, dengue and hemorrhagic shock syndrome. “Even certain types of bacteria which have been shown able to thrive in boiling water can have viruses growing within.”

Yet, as Harvey L. Ozer, MD, NJMS professor of microbiology and molecular genetics and Senior Associate Dean for Research, says, “Viruses are a clinically relevant tool for studying disease. There are certain aspects of viruses which help us identify the functions of cells and can actually change the properties of cells, specifically cancer.” In a longterm study, Ozer has been working on SV40, “the 40th monkey (simian) virus identified.” He chose SV40 because it’s a virus that likes to infect cells which are growing and actually promotes this growth. Once incorporated into a cell, SV40 becomes “part of the cell’s genetic material (DNA) and in the case of human fibroblasts — the focus of my laboratory — the cells become able to replicate for extended periods, up to 50 to 60 generations, and can even go on to grow forever or become immortal.” Human tumor cells are also immortal and capable of reproducing uncontrollably in a cell culture, so SV40 has been a useful experimental system to test Ozer’s theories not only about disease but also about aging at a cellular level. “We are now identifying alterations in cellular genes involved in this process, taking advantage of the recently completed human genome sequence, and the approach is going faster than ever,” he says.

Other viruses are proving to be even more versatile in University-wide biomedical research. Here are just a few examples of how viruses have invaded our UMDNJ laboratories:

  •  Take the “molecular trickery” used in the CABM lab of Eddy Arnold, PhD, and Gail Ferstandig Arnold, PhD. “Molecular trickery?” Yes, that is her terminology. The Arnolds and the virologists in their group are disguising the rhinovirus, which causes 50 percent of all common colds, to look in part like HIV to the immune system. “We’re making what are called combinatorial libraries of engineered viruses,” says Ferstandig Arnold, a UMDNJ-CABM senior research faculty member and research professor in the Rutgers department of chemistry and chemical biology. In the future, vaccination with such a hybrid could “fool the immune system into responding to HIV so that if a person ever gets exposed to HIV, he or she will have the immune memory. It’s going to take a variety of vaccines and maybe even different cocktails for different geographic regions,” she explains. “We think of it as dressing a sheep in wolf’s clothing.”

 •  At the UMDNJ Cancer Institute of New Jersey (CINJ) in the Hematologic Malignancies Tumor Study Group, Roger Strair, MD, PhD, and Daniel Medina, PhD, have chosen to harness the power of another mild-mannered, cold-causing virus. They are customizing mutantadenoviruses — the first viruses reported to be used in cancer patients — which ordinarily cause respiratory tract infections, and coaxing them to kill specific malignant lymphoid cells, though not yet in humans.

 •  Both murine (mouse) and feline (cat) leukemia viruses have been in the focus of Monica Roth, PhD, RWJMS professor of biochemistry. Looking for ways to deliver help to cells in trouble, Roth has generated a library of 10 million variations of a retroviral surface protein and can select for targeted entry into specific cells. Though not near the human trial phase yet, “We’ve identified a novel envelope protein which preferentially infects human osteosarcoma (143 B) bone cancer cells.” This approach is currently being developed as a means of cancer therapy. In her lab, they’ve seen viral mutations which were 10 times more efficient than their parent virus in infecting cells and able to mobilize as well as suppress viral activity.

 •  Michael Leibowitz, MD, PhD, RWJMS professor, molecular genetics, microbiology and immunology, is working on a virus with the “terrible name of killer.” It kills yeast, not people, he explains, and “offers us an exciting experimental system.” The protein produced by killer virus- infected cells can be easily measured by its ability to kill other yeast cells but “it also has viral gene expression controlled by a genetic element with prion-like properties.” (Mad cow disease, which grabbed news headlines this year, is a prion disease.) “At first we didn’t understand the novel element,” Leibowitz recalls. “We thought we were seeing a mutant form of the killer virus but after we eliminated the virus completely, my God, this thing was still there. Then, it turned out to have such unusual properties that it had to be something else and the only explanation we have is that it is a prion or infectious protein.”

Liebowitz and his group are working to define the nature of this prion-like genetic element and how it alters virus gene expression. This experimental system may lead to an understanding of prion-virus interactions.

 •  Not all viruses cohabiting comfortably in your cells will make you sick immediately or at all. So what will wake up a silent, deadly virus? Or better yet, keep it sleeping soundly? David Lukac, PhD, NJMS assistant professor, microbiology and molecular genetics, has been on the cellular pathway of Kaposi’s sarcoma-associated herpesvirus (KSHV) for years looking for stop and go signs. He remembers a particular moment as a post-doctoral student in California when he found Rta, a protein made by KSHV, “the only one that could reactivate this virus from latency.” His KSHV, also known as human herpesvirus-8, can cause at least three types of malignancies and “appears to have important differences from other transforming viruses.” By understanding these KSHV deviations, “We believe that we will uncover new mechanisms that lead to human cancer.”

 •  Viral pathways and wake-up calls have also been on the to-do list of Arnold Rabson, MD, since at least 1984 when he was at the National Institutes of Health. First working with HIV/AIDS in “what is as close to a Eureka moment as I have had, we showed that a particular pathway (NF-kappaB) was responsible for activating HIV that had been silent.” For the past eight years, his interest has shifted to a human T-cell leukemia virus (HTLV-1) which may infect up to 25 million people, explains Rabson, CINJ associate director and RWJMS professor of molecular genetics, microbiology and pathology. “Perhaps only one to two percent of infected individuals get sick with either a devastating leukemia (ATL) or a neurological disease of the spinal cord, both caused by HTLV-1.” Now, his UMDNJ lab has described cellular events that convert dormant viruses to active HTLV-1 with the potential for causing either disease. These cellular signals act through a viral protein called Tax, which is critical for both viral growth and disease. How the cell affects Tax function may hold a key to answering the question of why some people’s HTLV-1 awakens while others live on quietly carrying their dormant variety.

 •  Meanwhile, one of the herpes viruses, human cytomegalovirus (HCMV), “is the leading cause of birth defects, a major cause of death in immune-compromised patients, especially AIDS patients, and may be associated with atherosclerosis,” says Hua Zhu, PhD, NJMS assistant professor, microbiology and molecular genetics. For five years, Zhu has been working to understand how HCMV expresses itself in more than 80 percent of the world’s population. His research team has even identified the missing genetic pieces in safe or attenuated strains of this virus. With only one kind of medication on the market to control herpes and the spectre of a drug-resistant strain on the horizon, Zhu states, “Understanding viral-host interaction and viral gene replication will help us develop new anti-HCMV drugs.”

 •  Perhaps no one at UMDNJ is as humanly committed to the curative power of viruses right now as Edmund Lattime, PhD, CINJ director of surgical oncology research and RWJMS professor of surgery. Last November, Lattime opened an on-site National Cancer Institute trial for the viral treatment of recurrent bladder cancer. Up to 45 patients, who are still being recruited, will receive a vaccine made of an altered fowlpox, a relative of vaccinia, the vaccine for smallpox, carrying either one or two immune stimulating proteins. His preclinical findings show that a body can be coerced into creating an immune reaction to subsequent signs of the cancer. The news from three prior clinical trials Lattime helped to design at other medical institutions is also promising. In Philadelphia, for instance, patients who had lost hope of surviving persistent cancers, via traditional chemotherapeutic or surgical courses, were alive and cancer-free four years after their strange but powerful course of virotherapy.

Think of the words “fowl” in conjunction with “pox” and even if you aren’t a Shakespearean scholar — “a pox upon ye,” “cry foul” — both words connote a sense of doom and gloom or certainly not a very nice virus at all. For the hopeful, excited cancer patient signing up for a spot on Lattime’s virotherapy list, nothing could be further from that truth. The new director of a new UMDNJ training program aimed at moving more cancer research from the lab into medical practice and the recipient of a recent $1 million NCI grant, Lattime says, “We’re excited, too.”

Edmund Lattime, PhD, CINJ director of surgical oncology research and RWJMS professor of surgery