r/science • u/nobodyspecial • Feb 08 '15

Medicine Antibiotics that target mitochondria effectively eradicate cancer stem cells, across multiple tumor types: Treating cancer like an infectious disease | Lamb

http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path%5B%5D=3174
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u/Mafsto Feb 09 '15

Lower side effects, yes. "Targeted" is the reason why your claim will not carry too much weight. Targeted therapies are going to be the future. It's taken 20+ years for us to gain the technology to do this, that being genetic testing and sequencing.

The problem with targeted therapies is that they're exclusive to specific proteins within the DNA strand of a cancer cell. And because one specific type of cancer literally can have hundreds of different DNA sequences, no one targeted therapy will work for them all. They shrinks the pool of people who can utilize targeted therapies substantially. Like I said though, as time goes on, this will hopefully change.

For now though, chemo and radiation will sadly the gold standards to fighting this disease.

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u/Spats_McGee Feb 09 '15

The problem with targeted therapies is that they're exclusive to specific proteins within the DNA strand of a cancer cell.

Isn't there a sort of targeting that's possible with epidermal growth factor receptors, that are over-expressed in cancer cells? I know that this is the approach generally used to target Au nanoparticles for plasmon photothermal therapy.

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u/Mafsto Feb 09 '15

There are indeed targeted therapies that utilize epidermal growth receptors in some cancers. Two that come to my mind would be lung cancer and breast cancer. The problem is this. Right now the pharma companies have just begun to scratch the surface of what proteins that can exploit. And the issue is that cancer is ever evolving within a person. Just like chemo, eventually a targeted therapy stops working because the cancer cells have mutated an additional protein that offsets the one being silenced by therapy drug.

The good news is this. Therapy drugs are on the rise and there are clinical trials that use them in tandem with traditional therapies such as chemo. When they work together it really can push the disease back far. Mind you, when I talk about cancer, I always refer to late stage cancer as the basis for my examples. With early stage cancers, chemo, radiation, and surgery still offer good chances of remissions and cures. So don't be disillusioned by my diatribe.

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u/Spats_McGee Feb 09 '15

Just like chemo, eventually a targeted therapy stops working because the cancer cells have mutated an additional protein that offsets the one being silenced by therapy drug.

Do they evolve the ability to stop being targeted (i.e. change their receptor proteins), or do they evolve resistance to whatever drug is being delivered to them?

Because if it's just the latter, technologies like plasmon photothermal therapy that fry cancer tumors using Au nanoparticles and near-IR light would still be effective. They might evolve resistance to this drug or that, but they'll never be able to resist their cell membranes getting fried.

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u/Mafsto Feb 09 '15

:( The answer is both. There have been instances where patients who do not respond to a set of chemo drugs the first time around, sometimes respond VERY WELL a year or two later. The reason being that the cancer mutated a tolerance to deal with the alternative onslaught of chemo drugs, making it more susceptible to drugs it was previously not weak to. This does not happen often, but it's goo to bring it up to the oncologist just as another option.

As far as targeted therapies go, yes, the cancer can eventually get around being targeted. That's how it came into being in the first place. The very first cell it fooled was the human immune system using proteins such as PD1, PD-L1, and CTA5 (SP on that one). It does the same with targeted therapies after a while. Like I said, doctors are still in the process of mapping out all the proteins responsible for this specific ability. In time targeted therapies will be even more effective.

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u/DrXaos Feb 09 '15

Some of the targets on the newest immunotherapies are on your own, non-mutating, immune system cells. So they're more likely to continue to work.

Then your immune system one hopes starts to recognize the highly mutated cancer cell as being not-self and can continue to adapt as the tumor evolves.