Virus Tamed To Attack Cancer, Cancer Drugs To Treat Alcoholism

ScienceDaily is reporting that scientists at Oxford University seem to have adapted a virus so that it attacks cancer cells but does not hurt healthy cells. "Adenovirus is a DNA virus widely used in cancer therapy but which causes hepatic disease in mice. Professor Len Seymour and colleagues found that introducing sites into the virus genome that are recognized by microRNA 122 leads to hepatic degradation of important viral mRNA, thereby diminishing the virus' ability to adversely affect the liver, while maintaining its ability to replicate in and kill tumor cells." Relatedly, cancer drugs already approved for use may be cross-functional as a treatment for alcohol addiction. "Now, the researchers show that flies and mice treated with erlotinib also grow more sensitive to alcohol. What's more, rats given the cancer-fighting drug spontaneously consumed less alcohol when it was freely available to them. Their taste for another rewarding beverage -- sugar water -- was unaffected."

Comments

Replication is dangerous

[toppavak]

In any virus intended for therapeutic use in humans, allowing the virus to retain its reproductive mechanisms is just a bad idea. Viruses mutate rapidly and there's no guarantee that such a modified virus might not develop the right signals to enter and reproduce in healthy human cells. More promising efforts using engineered viruses involve the isolated production of viral structural RNA and coat proteins without the complete genome ever being copied or reproduced. This creates viral smart-particles that can be re-engineered to deliver payloads (therapeutics, contrast agents, nanoparticles etc) into targeted cell species. Nanovector is a recent start-up out of NC State University to commercialize this tech developed at a lab I used to work in as an undergrad.

Re:Replication is dangerous

[RDW]

'Not as dangerous as you'd think...Viruses pick up DNA strands from the host as they are made by the hosts cells, this is primarily what causes rapid mutation and why H1N1 contains human, swine, and avian DNA-this strain has been transmitted between these three animals'

The Flu virus is a rather unusual case - its genome (in fact RNA rather than DNA) is made up of 8 segments that can easily be swapped around ('reassorted') when two different strains infect the same animal (8 segments with 2 versions of each = 2^8 = 256 possible new viruses). This isn't true for the adenovirus used in the article, which has an unsegmented DNA genome, but there's still some concern that a therapeutic strain might 'recombine' with a wild-type strain:

http://vir.sgmjournals.org/cgi/content/full/89/2/380

This is one reason why you have to be careful when adding (e.g.) new genes to viruses of this type (as in gene therapy). It's rather less of a concern when doing the sort of experiment described in the original article, where the replication of the virus is partially blocked rather than enhanced, and where no new genes are added.