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Medicine Science

Bacteria In Tumors Can Inactivate Common Chemotherapy Drugs, Study Suggests (arstechnica.com) 38

Researchers caught the bacteria Mycoplasma hyorhinis hiding out among cancer cells, thwarting chemotherapy drugs intended to treat the tumors they reside in. The findings have been published this week in Science. Ars Technica reports: Drug resistance among cancers is a "foremost challenge," according to the study's authors, led by Ravid Straussman at the Weizmann Institute of Science. Yet the new data suggest that certain types of drug-resistant cancers could be defeated with a simple dollop of antibiotics alongside a chemotherapy regimen. Dr. Straussman and his colleagues got a hunch to look for the bacteria after noticing that, when they grew certain types of human cancer cells together in lab, the cells all became more resistant to a chemotherapy drug called gemcitabine. This is a drug used to treat pancreatic, lung, breast, and bladder cancers and is often sold under the brand name Gemzar. The researchers suspected that some of the cells may secrete a drug-busting molecule. So they tried filtering the cell cultures to see if they could catch it. Instead, they found that the cell cultures lost their resistance after their liquid broth passed through a pretty large filter -- 0.45 micrometers. This would catch large particles -- like bacteria -- but not small molecules, as the researchers were expecting.

Looking closer, the researchers noticed that some of their cancer cells were contaminated with M. hyorhinis. And these bacteria could metabolize gemcitabine, rendering the drug useless. When the researchers transplanted treatable cancer cells into the flanks of mice -- some with and some without M. hyorhinis -- the bacteria-toting tumors were resistant to gemcitabine treatment.

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Bacteria In Tumors Can Inactivate Common Chemotherapy Drugs, Study Suggests

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  • by Anonymous Coward

    This seems actually kind of reasonable. I'm pleasantly surprised that it doesn't seem like wildly out of context pop-science clickbait.

  • Deactivate (Score:1, Informative)

    by Anonymous Coward

    Really get someone with proper English language skills to proof read these crap headlines at least. I know the text beneath it is obviously too much, but at least fix the titles.

    • Inactivate - verb - make inactive or inoperative.
      "household bleach does not inactivate the virus"

      But please, go on about how smart you are when it comes to the English language

  • Symbiosis? (Score:5, Interesting)

    by Viol8 ( 599362 ) on Tuesday September 19, 2017 @06:50AM (#55224337) Homepage

    I wonder if there's some sort of symbiosis going on between the cancer cells and the bacteria? Food supply in exchange for protection? Perhaps certain bacteria in the body prefer tumours over normal tissue.

    I've not idea, just putting it out there. Perhaps I'm talking utter BS, just curious.

    • Re: (Score:3, Interesting)

      by cleavet ( 4094369 )
      That would be a valid avenue of research. My mother's myeloma has responded to chemotherapy much better since it was paired with an antibiotic. This allowed the oncologist to significantly reduce the dosage, with much less discomfort and lower cost.
    • by Guppy ( 12314 )

      Perhaps certain bacteria in the body prefer tumours over normal tissue.

      Many successful cancers are now known to have immune-suppressing features -- a major focus of research now involved "Checkpoint Inhibitors [wikipedia.org]" such as PD-1 [wikipedia.org] which interfere with these suppression mechanisms. The bacteria would probably otherwise would be involved in a raging immune battle, if not for the local down-regulation.

  • by dwywit ( 1109409 ) on Tuesday September 19, 2017 @06:52AM (#55224343)

    A bacteria species that can metabolize a drug designed to kill cells.

    Kill rapidly-dividing-and-growing cells of selected cancers, yes - but... it can drink a chemo concoction and just.... burp?

    That's almost scarier than the cancer itself.

    • by Solandri ( 704621 ) on Tuesday September 19, 2017 @11:26AM (#55225347)

      A bacteria species that can metabolize a drug designed to kill cells.

      The wiki page on how gemcitabine works [wikipedia.org] is pretty fascinating. The drug as administered doesn't kill cells. It gets modified by enzymes in the cell into a form which interferes with DNA replication and blocks DNA repair. That's what kills the cell.

      Presumably the bacteria are just metabolizing it before these enzymes can convert it into its toxic form (or lack one of the needed enzymes). So no, not a superbug which digests a toxic material.

      • It's interesting...

        Another way to think about this is that standard drug pharmacokinetics studies are performed as part of determining dosage and clinical efficacy during clinical trials for (nearly) every pharmaceutical past and present on the market. The metabolic studies are usually performed using tissue cells, liver extracts, and mouse models, which covers the majority of degradation pathways that your drug is likely to encounter...from mammals. What's generally missing is any consideration for commens

  • by Anonymous Coward

    I wonder if there is a way to ensure that the bacteria only goes where we want? If so we could reduce many of the side effects of chemo by protecting the bone marrow and lymph systems.

  • by king neckbeard ( 1801738 ) on Tuesday September 19, 2017 @08:35AM (#55224577)
    If we've got bacteria that can shield cells from the effects of chemotherapy, then that could potentially be very useful. If we can get it to do the same thing for the rest of the body in a relatively benign way, then it might greatly improve outcomes for chemo patients.
    • by jafiwam ( 310805 )

      If we've got bacteria that can shield cells from the effects of chemotherapy, then that could potentially be very useful. If we can get it to do the same thing for the rest of the body in a relatively benign way, then it might greatly improve outcomes for chemo patients.

      Pre-infect kidneys and liver with the bacteria beforehand and help prevent the chemo from causing other problems, or allow for higher dosages.

      • by Binestar ( 28861 )

        Pre-infect kidneys and liver with the bacteria beforehand and help prevent the chemo from causing other problems, or allow for higher dosages.

        And when we're done we'll send rabbits down to eat the bacteria, and then foxes to eat the rabbits, then ...

  • I'm actually working on converting paper chemotherapy orders to electronic at the moment, and I'm wondering if we are going to need to make slight modifications to our regimens. This is a pretty interesting study. Methinks I'll share it with our lead pharmacist.
  • Pretty scary stuff. The human race isn't going to be wiped out by global warming. We are all going to catch something incurable from one of those little ankle-biters crawling around the floor at Starbucks.

  • If certain bacteria can inactivate chemotherapy drugs, that could skew the data as to how effective the treatment was. A new drug might seem to be less effective than it really is unless the testing protocol takes this into account.

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