Posted on 09/10/2002 7:16:04 PM PDT by mjp
Cancer breakthrough stuns scientific world
September 05 2002 at 08:26PM
By Steve Connor
Scientists have successfully destroyed cervical cancer cells using a revolutionary new technique which is being hailed as one of the most important developments in medicine for decades.
The technique, called RNA interference (RNAi), completely eliminated all the cancer cells growing in a test tube yet left healthy cells unharmed. The scientists called the results "absolutely remarkable".
As the findings were released on Thursday, it emerged that another team of researchers were planning the world's first clinical trial of the technique, this time on a group of Aids patients. The trial is expected to begin within the next two years.
'I've been in research a long time and this was fantastic' RNAi works by "silencing" harmful genes. Excited scientists believe it could be used to turn off the genes of infectious viruses or human tumour cells that have turned malignant, rendering them harmless.
A study published yesterday in the journal Oncogene demonstrated that RNAi efficiently switched off the genes of the human papiloma virus, which triggers cervical cancer in women. All cancerous cells growing in a test tube died, leaving normal cells untouched.
Professor Jo Milner, who led the investigation at the University of York, said that in her long career as a cell biologist she had never before witnessed such a powerful anti-cancer agent which was so highly specific at targeting tumour cells.
"The successful elimination of the cancer cells, without adverse effects on normal cells, is absolutely remarkable. I've been in research a long time and this was fantastic," she said.
Milner's team targeted the RNAi against two genes of human papiloma virus. By silencing one gene, the tumour cells stopped growing. By silencing the other, all the cancer cells "committed suicide".
Because the treatment had no effect on uninfected human cells, this is strong evidence that RNAi would be unlikely to produce the harmful side-effects seen when other cancer treatments are used on patients.
Milner said she intended starting clinical trials as a potential treatment for cervical cancer within five years. Cervical cancer is the second-most-common form of female cancer, killing 1 250 British women a year.
"Our work has identified a novel agent with major therapeutic potential for the treatment, and possibly the prevention, of human cervical cancer," Milner said.
Cervical cancer is caused when human papiloma virus attacks natural proteins in the body which are vital for the suppression of cancer. RNAi effectively restores this natural cancer-suppression by attacking the virus. - Independent Foreign Service
This is, of course, only in vitro, where a number of things seem to work that end up killing the patient in vivo. But it is very promising. That it is a mechanism for apoptosis as well as gene suppression is even more exciting - there are a number of apoptosis-activators currently in clinical trials but I don't know of any that sound this promising. Oncology isn't a magazine known for hype or journalistic hysteria, either.
For those who care, the reason AIDS patients are in this is that they are a conveniently immune-suppressed population that is willing to act as human guinea pigs. I don't care how they got that way, I'm just glad they're volunteering. That is always the most difficult hurdle for treatments involving gross somatic effects, getting something approximating the human organism to act as a disease model for toxicity studies and projected dosages. Unless I'm missing something pretty big this is not a cure for AIDS, it's a potential cure for tumor cancers.
Oncogene? Maybe a great journal, but first time I've ever heard of it.
Oops - I thought I'd read "Oncology." Oncogene is a much smaller mag, but it is peer-reviewed. It's part of the Nature Publishing Group, named after that eponymous parent mag. I work at a place that subscribes - I'll be checking this one out when this issue arrives.
I wish. And it isn't the FDA's fault, either. One of those patients dies and the relatives sue the company - drug companies are all big and rich, dontcha know - sue for the Big Bucks. Ain't gonna happen.
Besides, it's a long way from dropping the stuff into a suspension of cancer cells and managing to get it into the appropriate site in the body in the proper concentration, once we even figure out what that is. Shoot enough straight penicillin into a patient and you kill him. This is nowhere near ready to field yet.
RNA silencing is a eukaryotic genome defence system that involves processing of double-stranded RNA (dsRNA) into 21-26 nt, short interfering RNA (siRNA). The siRNA mediates suppression of genes corresponding to the dsRNA through targeted RNA degradation. In some plant systems there are additional silencing processes, involving systemic spread of silencing and RNA-directed methylation/transcriptional suppression of homologous genomic DNA.So, once again, we have an example of the benefits of molecular biology's exploitation of nature.
--EMBO J 2002 Sep 2;21(17):4671-4679
Two classes of short interfering RNA in RNA silencing.
Hamilton A, Voinnet O, Chappell L, Baulcombe D.
Selective silencing of mammalian gene expression has recently been achieved using short interfering RNA (siRNA). Synthetic siRNA targets homologous mRNA for degradation and the process is highly efficient. Here we demonstrate siRNA silencing of pathogenic viral gene expression. As a well characterized model we chose cervical carcinoma cells positive for human papillomavirus type 16. Over 90% of human cervical cancers are positive for papillomavirus and abnormal cell proliferation is driven by co-operative effects of viral E6 and E7 genes. We sought to silence HPV E6 and E7 gene expression using siRNAs to target the respective viral mRNAs. Our results indicate selective degradation of E6 and E7 mRNAs. Silencing was sustained for at least 4 days following a single dose of siRNA. E6 silencing induced accumulation of cellular p53 protein, transactivation of the cell cycle control p21 gene and reduced cell growth. In contrast, E7 silencing induced apoptotic cell death. HPV-negative cells appeared unaffected by the anti-viral siRNAs. Thus we demonstrate for the first time (i) that siRNA can induce selective silencing of exogenous viral genes in mammalian cells, and (ii) that the process of siRNA interference does not interfere with the recovery of cellular regulatory systems previously inhibited by viral gene expression.
It would work similarly in cancer to stop the production of certain cancer associated proteins.
That's one of the strangest posts I've ever read. You seem to be thrilled that some people will die of a disease,and even claim to be proud of this? Your hatred of homosexuals is greater than your joy at a discovery that will end a long and painful illness that leads to death. VERY strange.
wHY WAIT SO LONG. aND WHY START TESTS ON aids PATIENTS??? Sheesh, Cancer should have been cured years ago if not for billions of dollars being diverted to save Magic Johnson's et al life.
AND if it turns out to be a cure for AIDS also,even 'mo bettah.
Sorry, the government can't take the chance that the dying patients might get sick.
The government has sentenced them to death. Death by government.
Free people can make their own decisions about their own health. But of course we are not free.
We wouldn't want dying people to have a chance to live if they might die from something else would we? Makes perfect sense.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.