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'Virotherapy'.. Ever Waiting Hope For Cancer Treatment?


Wed 21 Nov 2018 | 08:34 AM
Yassmine Elsayed

By: Yassmine ElSayed

CAIRO, Nov. 21 (SEE) - Along history, scientists have been obsessed with searching for a comprehensive treatment for ‘Cancer’. By time, they come to discover causes for the disease or nutrition and physical tips to avoid being infected. But once the disease enters a body, it’s all about attempts to contain it and prevent it from spreading. Relatively few attempts succeed in curing the disease, including surgical treatment.

For decades now, attempts are continuing to search for a treatment, every hope counts, every finding is paid significant attention perhaps it will be the ever waiting solution.

In a new livescience.com piece, ‘Virotherapy’ was mentioned. A quite new concept, which implies that some viruses can kill cancer, a fact which scientists have known for over a century.

It's only in the past few decades, though, that advancements in genetic engineering have enabled viruses to become a viable cancer therapy. Now, researchers around the world work with these cancer-killing bugs in the hopes that cancer treatment will someday go viral.

Some viruses prefer to attack cancerous tissues rather than healthy ones, and oncolytic virotherapy takes advantage of this fact. Anticancer viruses not only kill off tumor cells but also alert the host immune system to a cancer's presence.

Dr. Antonio Chiocca, neurosurgeon-in-chief and chairman of the department of neurosurgery at Brigham and Women's Hospital in Boston said that scientists began experimenting with this type of immunotherapy as early as the late 1800s, but over the next 100 years, the field fell in and out of fashion.

 

In the early 1900s, a surgeon named William Coley became famous for his attempts to fight cancer by exposing patients to extractions drawn from infected tissue. Coley became hooked on the concept after meeting a man whose malignant tumor withered in the face of a severe bacterial infection. Coley began infecting his patients with a bacterial savior — the erysipelas virus — and later developed a vaccine from two modified bacteria.

 

"Coley's toxins," as the vaccine was called, became a popular treatment for many cancer types and worked by inducing fever, chills and inflammation in the patient. Numerous case studies supported the idea that infectious disease could send cancer into remission, or eliminate it completely. But with the rise of radiotherapy, chemotherapy and other immunosuppressive treatments, emerging virotherapies like Coley's toxins lost popularity.

The development of tissue-culture systems and rodent cancer models in the 1940s and '50s sparked a resurgence of virotherapy research. Doctors infected hundreds of cancer patients in clinical trials, exposing them to the mumps, hepatitis and West Nile. Success varied widely between trials. Some patients' tumors regressed dramatically and their lives were prolonged. Others fought off the infection too quickly to reap its benefits, while still other patients emerged tumor-free, but later fell victim to the virus itself rather than their cancer.

 

The 1980s ushered in the modern era of oncolytic virotherapy, and since then, the field's prospects have been looking up.

 

"Molecular virology came into play, and people discovered that certain viruses would replicate better in cancer cells than in their normal counterparts," said Grant McFadden, the director of the Biodesign Center for Immunotherapy, Vaccines and Virotherapy at Arizona State University.

When cells become cancerous, he said, they gain dangerous features at the expense of beneficial features found in healthy cells.

With the help of modern genetic engineering, researchers now strive to build the best oncolytic virus they can and then match the virus with its cancerous archnemesis.

Anticancer viruses can now be engineered to selectively attack cancer cells, spare normal tissue, awaken the host immune system and reverse immunosuppression in the tumor microenvironment. But virotherapy is not a cure on its own. Research suggests that virotherapies will serve to supplement chemotherapy, radiation therapy or immunotherapy.

As diligent scientists search for powerful oncolytic viruses, the field of virotherapy seems destined to continue to expand.