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Genetically Modified Salmonella Destroys Cancer By Provoking An Immune Response, Study Finds (sandiegouniontribune.com)
schwit1 quotes a report from San Diego Union-Tribune: A genetically modified bacterium destroys tumors by provoking an immune response, according to a study published Wednesday. Using mice and cultures of human cancer cells, a South Korean-led scientific team demonstrated that Salmonella typhimurium engineered to make a foreign protein caused immune cells called macrophages and neutralizes to mobilize against the cancer. The bacterium came from an attenuated strain that has little infectious potential. Such strains have been tested as vaccines. The protein, called FlaB, is made by a gene in the estuarine bacterium Vibrio vulnificus, a close relative of the cholera bacterium, Vibrio cholerae. Tumors shrank below detectable levels in 11 out of 20 mice injected with the modified Salmonella, said the study, published in Science Translational Medicine. The engineered Salmonella provoke a sustained immune response, in addition to preventing the spread of a human colon cancer implanted in a mouse. The bacterium also were found to be nontoxic, multiplying almost exclusively inside tumors.
Having lost dear family members and friends to cancer variants, I follow such news items with interest.
Yes, this above study was with mice, not yet a trial on humans. But even so I have the impression that significant breakthroughs are now being made regularly, and then there is Microsoft throwing machine learning at the problem, all of which leads me to wonder - will we soonish be able to cure all cancer? That would be truly a breakthrough for for society.
Any insights from people in the field?
BCG (Bacillus Calmette–Guérin, still a common base for TB vaccines today in many countries) has been a standard treatment for bladder cancer (specifically: non-muscle invasive bladder cancer) since the late 70s. As it was explained to me in medical school in the early 90s, before molecular biology was widely understood by physicians (at least not to my standards -- I was a molecular biologist before med school), it was a general stimulant of local immune response, but I always suspected it was something more specific.
The idea of a specific immunological cross-reactions has been well known in medicine for maybe 80 years. "Rheumatic fever" caused by Group A ß-hemolytic streptococci often triggers heart/valve damage because antibodies produced in response to a bacterial protein often cross-react with a structural heart protein. In this example (once called "rheumatic" heart disease or valve damage), the effects are negative. I always thought deliberately targeted cross-reactions were an obvious path for treatment investigation, and was frustrated that it never seemed to be very actively pursued.
In truth, it probably has been, many times. Some positive studies were likely published; others were equivocal or lack sufficient (statistical) power. Some failed.
As a space enthusiast, I always say "space is hard". Biology is harder. Even I forget that, mostly because a molecular biologist's first reaction is to try to think of easy ways to explore/prove their latest idea (trying hard to ignore the fact that their "quick elegant" experiment will likely take years to bear compelling evidence, due to complications) -- and a physician? Well, even we forget the truth/depth of the aphorism "it's an art as much as a science".
I'm hoping we'll be seeing a LOT more results along this line of inquiry in the coming decade, because I'm hoping we're finally ready to really explore it. We may not be, yet. Molecular simulations may not yet be at sufficient reliability, and the combinatorial math may yield too many permutations for empirical trials
If you can go to bed, knowing you did a valuable thing today, you're very lucky. If you can't... it's not bedtime
If you click two layers deep you can read the scientific article. The "immune response" to the bacteria isn't mentioned in the abstract of the paper, because it is not relevant to the tumors shrinking. It might even be bad news for the anti-cancer mechanism.
The "foreign protein" that was genetically added to the bacterium is FlaB, and FlaB (http://onlinelibrary.wiley.com/doi/10.1111/j.1574-695X.2009.00643.x/full paragraph 2 after the abstract) triggers the TLR5-mediated cell death pathway.
They tested this bacterium in TLR5 (Toll-like receptor 5) negative tumors and found that the FlaB induced shrinkage of the tumors. The immune response to the bacterium was not the mechanism for the tumor shrinkage, the bacteria-produced FlaB proteing was.
If slashdot wants to be "News for Nerds" they should do better than re-using the words from a gloss of a scientific article. If you click the link provided, you find a mainstream news article that emphasizes the immune response, implies the immune response is the mechanism, calls FlaB a "foreign protein" (which is true, but one of the least relevant details about it) and doesn't mention that this was only tried in TLR5-negative tumors.