Help me poke holes in this

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amazinghat
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Help me poke holes in this

Postby amazinghat » Mon May 16, 2011 2:27 am UTC

http://hubpages.com/hub/Scientists_cure_cancer__but_no_one_takes_notice

That seems like really bad anti-pharmaceutical-company propaganda right there. Also, I think it's BS based on the part about "curing cancer".

qetzal
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Re: Help me poke holes in this

Postby qetzal » Mon May 16, 2011 2:37 am UTC

This is about dichloroacetate, a cheap generic compound that does seem to have activity against cancer cells in culture and in animals. But it has certainly NOT been proven to even treat cancer in people, much less cure it. It's apparently been tested in 5 people with one type of cancer, and may have shown some activity (tumor shrinkage), but with so few subjects, it's impossible to conclude that it's a real effect of the drug. See here for more info.

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Charlie!
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Re: Help me poke holes in this

Postby Charlie! » Mon May 16, 2011 5:42 am UTC

http://en.wikipedia.org/wiki/Dichloroacetic_acid

"In 2010 it was found that for human colorectal tumours grown in mice, under hypoxic conditions, DCA decreased rather than increased apoptosis, resulting in enhanced growth of the tumours.[25] These findings suggest that at least in some cancer types DCA treatment could be detrimental to patient health, highlighting the need for further testing before it can be considered a safe and effective cancer treatment."
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Re: Help me poke holes in this

Postby Angua » Mon May 16, 2011 6:52 am UTC

1) the mitochondria is not a cell, it is an organelle

2) I've never been told about mitochondria switching off completely in cancers - the apoptotic pathways do, yes, but mitochondria generally stay on (which is why most cancers need a good blood supply).

3) Most chemotherapeutics attack DNA or it's synthesis and cell cycle replication - not glycolysis (which if you did target would quickly kill all your red blood cells as they don't even have mitochondria)

4) I'm pretty sure lactic acid doesn't play any major role (and I've never heard of even a minor one) in breaking down the ECM, and a lot of other proteases and growth factors (some of which are actually secreted by your immune system, not the actual cancer cells) are generally involved.

I have exams this week (first one today) so I don't really have time to read the actual study, which I"m sure is a lot better than the article, but the article has no understanding, at all, of cancer.
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Gigano
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Re: Help me poke holes in this

Postby Gigano » Mon May 16, 2011 7:59 am UTC

It seems that this article somehow presents glycolysis as something bad, that should be deactivated to prevent cancer. Glycolysis is however of vital importance in human energy metabolism. It is the process in which glucose is broken down to generate some ATP (an energy source for a lot of cellular reaction). The metabolites formed from glycolysis enter the citric acid cycle where NADH and FADH2 are produced. These two molecules are electron donors, which donate their electrons to membrane proteins in the mitochondria. The interaction between the donated electrons and the mitochondrial membrane proteins trigger the transportation of hydrogen ions (proton) to form a electric proton gradient. The potential energy of this gradient is used to drive an enzyme called ATP-synthase, which produces in effect about 30 ATP molecules per glucose molecule consumed. Producing ATP through this proton gradient is known as oxidative phosphorylation, and requires oxygen to scavenge the electrons used to power the proton pumps. Because oxygen is required in this process it is known as aerobic respiration. Without oxygen, oxidative phosphorylation cannot work and the cell resorts to anaerobic respiration and the cell metabolises glucose to some ATP and lactic acid. This is known as fermentation, and is less effective in producing ATP than aerobic respiration.

So, this article seems to misrepresent glycolysis as being the same as oxidative phosphorylation, which simply isn't the case. Turning of glycolysis will not cause a cell to commit to fermentation and produce lactic acid, as is said in the article, because it is glycolysis which provides the substrates required for fermentation to begin with. And although mitochondria are indeed involved in apoptosis, cells do not die due to the apoptotic mechanism in mitochondria because one halts glycolysis. The cells die simply because do not produce any ATP, and thus run out of energy. Also, this article seems to present mitochondria as being a sort of "natural cancer killing cell". It has already been pointed out by Angua that mitochondria are not cells, and what's more ironic, is that mitochondria can be a source of cancer themselves because they can generate a lot of oxygen radicals, which in turn can damage DNA and lead to cancerous growths.

This is typical pseudo-scientific stuff that is supposed to impress the people who have little to no knowledge of biology. What's even more bizarre is that they post links within the text to Wikipedia articles where all of the above given information can be found.
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qetzal
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Re: Help me poke holes in this

Postby qetzal » Mon May 16, 2011 4:38 pm UTC

Just to be clear - the idea that dichloroacetate (DCA) might have activity against some cancers by interfering with glycolysis is based on real science. Some blog discussions by scientists who know what they're talking about can be found here and here.

What's bogus is the claim that DCA is some miracle cure for cancer(s) in humans. It may turn out to be useful for treating some cancers. It won't be a panacea.

The whole thing reminds me a lot of the endostatin story. That was another case where some very nice animal data caused a lot of people to go nuts and predict that all cancers would be cured in a few short years. Sadly, endostatin was a bust in human clinical trials. Other drugs that work by the same mechanism as endostatin (antiangiogenesis) have since been proven to work in humans (e.g. Avastin), but they don't come close to being cures.

It would be great if DCA proves to be even 1/10th as good as the hype would have it, but don't hold your breath.

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Re: Help me poke holes in this

Postby Sir_Elderberry » Mon May 16, 2011 5:18 pm UTC

PZ Myers did another pretty good blog post on it here.
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