Another day, another disease treatment strategy based off a genetically modified virus!
This one is so clever, you guys. It is so freaking clever!
Some of you might know that sometimes, when prostate cancer is present, there is an elevated level of 'Prostate Specific Antigen'. Physicians used to test for elevated PSA levels as a test for prostate cancer, but because it lead to over-diagnosis/unnecessary treatments, its not anymore.
But lets say you *know* prostate cancer is there, and it is causing difficulties. PSA is usually there, over expressed.
Well 'PSA' isnt a marker put in our genome by The Creator to be a marker for prostate cancer. It has a normal cellular function-- PSA is an enzyme. Its function is to cut stuff.
Newcastle Disease Virus-- the protein it uses to infect cells needs to be cut before it can initiate infection.
So they made the virus need PSA. They genetically modified the virus to need PSA to cut its fusion protein to infect cells.
A cancer killing virus that can only infect cells that have lots of PSA on the surface, or when there is a lot of PSA floating around-- prostate cancer cell lines that over-express PSA, and hopefully, prostate tumors that over-express PSA in patients.
I have to say 'hopefully' because it has not been tried in humans yet, and a previous generation of NDV against prostate cancer did work in mice (but they havent tried this one yet). It might not work at all, but I wanted to highlight the extremely clever ideas coming out of these GMO virus labs. Incredible!
I forget just where, but I saw a similar trick: a cell surface protease, expressed just on the cancer cells, was leveraged (and required) to cleave your injected pro-drug into the active compound. Can't recall the damned details though. Maybe I saw it in NCI cancer bulletin. Sorry for not searching harder - the job, gotta do it. I was impressed. Maybe it was this paper but I thought it was longer ago than that.
I recall writing hateful comments at the time, cause the lay press were all atwitter about someone's paper using radioactive gold nanoparticles targeted to some cell surface protein - which by comparison is a sharp as a bowling ball. Radioactive decay all over the place, with some extra near the tumor cells, hopefully. And that was in mice whereas the other drug was in phase II's already. The gold folks had been doing press-releases.
I tried harder: It was cancer bulletin that clued me in.
"G202 delivers its toxic payload—a potent analog of the plant substance thapsigargin—to tumors by binding specifically to a protein known as prostate-specific membrane antigen (PSMA)."
" G202 is an inactive "prodrug," and PSMA causes the release of the active, cell-killing thapsigargin analog from the prodrug form."
Sorry, no virus backstory ;)
What does ENV stand for?
Env is the protein on the outside of retroviruses that mediates infection of a new target cell :)
Commentary on the latest claim of a functional infant HIV cure via antiviral drugs alone ....if you please.