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RNA-Loaded Nanoparticles Fight Cancer
DirkDaring writes "It's been promised for years: that nanoparticles offer a treatment to many forms of cancer. Today, an important first step has been announced. In a new human trial, nanoparticles carrying RNA have successfully reached cancer cells and silenced the target gene. 'The researchers developed a nanoparticle carrying a molecular marker that binds to the surface of cancer cells, triggering the cells to absorb it. The siRNA carried within the particle was designed to silence a gene called ribonucleotide reductase M2 (RRM2), which regulates DNA synthesis and repair and is known to be an anticancer target. Because it was the first trial using targeted RNAi delivery for cancer, says Mark Davis, a professor of chemical engineering at Caltech and the study's lead author, "we wanted to choose a gene that was suspected to be hugely upregulated in a broad spectrum of cancers" in order to increase the likelihood of being able to observe the novel therapy's effect. The researchers analyzed biopsy samples from three melanoma patients in the trial who had received different doses of the therapy. They tracked the particles in the different samples, finding that the amounts they could see in the tumor cells correlated with the doses the patients received.'"
Since the marker attaches to cancerous cells only, healthy ones should suffer no damage. Then again, I read the story above, so it's not like I'm specially insightful.
The most interesting part here is not about directing damage, it is that this was a successful non-topical application of siRNAs. In most tests up to now, siRNAs have been injected directly into the target tissue. This study shows a delivery system that carries the siRNA specifically into targeted cells via the bloodstream. In the long run, this might be the key to target metastases however small they are and wherever they are.
Ubi solitudinem faciunt, pacem appellant.
Maybe I'm going out on a limb here, since I practically no medical schooling, but there have been suggestions by certain medical professionals (names elude me at the moment) that cancer cells could be the body's final (and potentially fatal) attempt to correct other, seemingly unrelated health issues. This would also explain why cancer can return after it has gone into remission.
If so, while this technique would stop the cancer cells from spreading, it may not address the cause of the cancer. I suppose we'll find out if/once the treatment becomes mainstream.
have been suggestions [..] certain medical professionals [..] could be
That are too many weasel words, and I raise a pseudo science alert! While I don't claim to know better, taking a potshot at conventional medicine with a very vague concept is not helpful.
Also, cancer cells are no longer within the normal parameters of human cells and mutate wildly, please suggest how they could be in any way helpful.
See paper here http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08956.html and article here http://www.nature.com/news/2010/100321/full/news.2010.138.html
Why do I keep seeing summaries that link to articles that are summaries of summaries of the original publication? Just link to the damn Nature article if that's the source.
HIV mutates very frequently, so it's difficult to design an siRNA reagent to target it effectively. Another hurdle is delivering the siRNA to the infected T cells.
No, the point is cancer cells evolve faster than we can understand the proteins they express. The patient is welcome to continue treatment, but the RNA won't bind to the evolved cells (cell epitopes change), so the patient dies from cancer in the long run anyway. Knocking out 100% of the cancer isn't impossible, but it's not probable.
And if, for instance, the patient has brain cancer, it's probably going to be difficult continuously getting samples of the cancer so treatments can coevolve with the cancer. The immune system is good at evolving quickly, which is one of the reasons immunotherapy is so promising.
Unfortunately, as the patient ages, their immune system will become ever more ineffective for a number of reasons.
One way to get your head around all the problems with aging, and how to neutralize them, is http://en.wikipedia.org/wiki/Strategies_for_Engineered_Negligible_Senescence
Unfortunately, the SENS way of dealing with cancer destroys every cell's ability to lengthen its own telomeres. That's fine for guaranteeing you won't develop cancer (now even your cancer cells can only divide a finite number of times) , but the patient should be ready for life-long stem cell infusions for the bone marrow, gut, and elsewhere. So perhaps if the disease doesn't kill the patient, the treatment will.