Scientists narrow down the mechanism whereby cancer cells metabolise sugar | Hacker News Reader

Scientists narrow down the mechanism whereby cancer cells metabolise sugar

sciencealert.com

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It seems to me that "sugar" is a very vague term. Fructose and glucose are very different. For example their glycemic indices are 19 and 100 respectively, yet they are both sugars.

Is it reasonable to talk about the health impact of sugar at all? For example, the article says:

> This link between sugar and cancer has sweeping consequences.

Does that refer to sugar I eat? Or sugar my body makes from carbohydrates I eat? And are glucose and fructose equally linked to cancer? What about all the other sugars?

Related to the title of this article, cancer metabolizes the main sugar in the bloodstream, glucose, that all cells metabolize.

GI measures glucose, so it makes sense that a substance that is not glucose has less GI than glucose itself. However that doesn't mean fructose alone is better than glucose. In fact it's much, much worse.

do you have more material on that so I can understand?

https://www.youtube.com/watch?v=f_4Q9Iv7_Ao

I also recommend the rest of the channel.

> The team used yeast cells for its research – specifically looking at the 'Ras' gene family, a family of genes that is present in all animal cells, including human cancer cells.

Hmm.. So they could have used any opisthokont's cells for a model, but they chose a fungus, a type of organism that travels readily in the environment as micrometer-sized spores and on even forms yeast, a zoomorphism which just so happens to match the growth and feeding patterns of cancer.. makes sense.

They chose yeast because a lot of the basic eukaryotic biology is conserved (as compared to humans) and it's basically free to grow more yeast quickly. This means you can run your experiments super fast.

Conversely, the above has resulted in a big number of yeast trained molecular biologists, who end up applying yeast work wherever they can (see: law of the instrument). Sometimes it works, sometimes it doesn't.

Can cancer cells metabolise ketones?

I think they struggle to. I remember hearing a theory that the biggest reason chemotherapy works is that patients have trouble eating, and they slip into ketosis. Thomas Seyfried has done a lot of research on this subject.

Cancer: A Metabolic Disease With Metabolic Solutions. https://www.youtube.com/watch?v=SEE-oU8_NSU

Remember that "cancer" is just normal cells that grow out of control. So if your normal cells are functioning normally then cancer cells will also function normally. If ketosis stopped cancer cells from proliferating the same would go for all other normal cells of the specific tissue.

Ketosis has shown to be good for quicker recovery from chemotherapy.

>Remember that "cancer" is just normal cells that grow out of control. So if your normal cells are functioning normally then cancer cells will also function normally.

But that only holds if growing out of control has no impact on normal function. If, say, cancer cells reproduced faster than their own mitochondria, then those cancer cells would function differently from normal cells in a particular sense: they could metabolize sugars into pyruvate but not all the way to CO2 + H2O. And that in turn could have other consequences.

True. I was only referencing what they use as energy, i.e. the same sugars (etc.) that their normal growing and dying counterparts do.

>Remember that "cancer" is just normal cells that grow out of control.

This statement glosses over how important the molecular processes of cellular metabolism and mitosis are, how they are linked, and why cancer cells are aberrant. I don't think one can call a cancer cell a normal cell that is growing out of control.

> I don't think one can call a cancer cell a normal cell that is growing out of control.

This is pretty much the characteristic ability that cancerous cells have.

I can be more specific if you'd like.

Ugh can we just put AlphaGo deep learning on diet / cancer/ food studies? One week meats are bad, next week meats are great dont eat carbs!

I'm getting javascript framework diet fad of the week fatigue

Are we getting mixed signals about sugars, though? Proteins and carbs have had their ups & downs, but I don't recall ever hearing any praise for sugars.

the problem with this approach is that the training data set just sucks.

humans are fully capable of doing the statistics to get proper answers on these questions without ML. we just cannot trust the data enough,because to get a reliable data set we would have to imprison a few tens of thousands of people for 60 years and control every aspect of their exercise and diet, and that sort of thing usually gets you arrested.

>One week meats are bad, next week meats are great dont eat carbs

I don't think this is a problem with our learning, but a problem with our unrelenting desire to compress complex subjects and findings into easily digestible morsels that people can understand without too much thought.

Deep learning isn't going to help with that.

This research is getting misused badly and is a very lucrative business selling to cancer patients in the „alternative medicine“ sector.

I lost my uncle last year to small-cell lung cancer (age 40). Doctors gave him 12 months after the diagnosis, turns out he barely had 3 months (mostly due to a very bad response to chemotherapy). In his last months he turned to one of these alternative medicine gurus who told him that the tumor (quote) „would eat itself“ if he stops eating sugars.

Was your uncle a smoker or otherwise at risk? Is this something anyone can get? It sounds terrifying to realize you have that little time left at such a young age.

Sorry if this is too personal of a question.

Yes. What (might have) increased the likelihood:

- him being a heavy smoker (SCLC almost exclusively in smokers)

- running a car repair shop and inhaling fine dust frequently

Despite these factors he was very unlucky developing cancer at such an early age.

Survival rates for SCLC: http://www.cancercenter.com/lung-cancer/statistics/tab/lung-...

Unfortunately anyone can get cancer at any age. Body gets thousands of cancerous cells daily. Typically it is not a problem as those cells are get killed by the immune system. The problem starts when those cells stuck and starts to multiply. But even then it may takes many years before the growth can be detected and starts to affect health. A person can get a cancer from single exposure to a highly carcinogenic factor and get cancer as sickness 20 years later.

The best one can do is try to minimize risk factors to either avoid cancerous growth or at least to slow it down to the extent that it does not affect life expectancy.

As mentioned elsewhere in the thread, chemo may work due to a forced state of ketosis. The "would eat itself" hypothesis, although it sounds cheesy has a bit of truth grounded in many recent studies. But stopping eating sugars is not enough, at all. He would have had stopped eating any carbs (<5% of calories from carbs) and not too much protein (<10-15% of calories in protein), because both are converted to sugar quite easily. That means eating more fat instead so the body uses ketones instead of sugar. And much more salt, sodium and magnesium to avoid the infamous "keto flu".

jesus that title's misleading.

THe actual paper is about the https://en.wikipedia.org/wiki/Warburg_effect Warburg effect (the observation that cancerous cells rely heavily on glycolysis). People have wondered about causation, and this group has offered some mechanistic answers that help get us closer to knowing if glycolysis spikes _because_ you have cancer, or you get cancer because you lean on glycolysis.

I read your post, and while the nuance is a bit different, it's not that misleading relative to your understanding of it. And they cite the Warburg effect plenty. I think showing that it is causative instead of correlative is in effect showing how sugar exacerbates cancer.

As the GP, I do not think the title is correct. The Warburg effect does not tell that sugar causes cancer, it tells that cancer cells prefer one of the two mechanisms to create ATP.

This mechanism is the glycolysis (something used in fermentation), which is much less effective than the other mechanism which uses oxygen (used indeed in respiration) to produce ATP.

From the article abstract, they hint that the cell cycle is quicker with glycolyse than with respiration.

Study in question:

Fructose-1,6-bisphosphate couples glycolytic flux to activation of Ras (2017)

https://www.nature.com/articles/s41467-017-01019-z

Background: https://en.wikipedia.org/wiki/Warburg_effect

From what I recall (k)RAS gene is also a marker in incurable lung cancer lines.

You are correct. However, this paper specifically only looks at H-RAS, also a proto-oncogene.

so the three major killers have one cause? Cancer, heart attacks and diabetes are simply from overeating sugar and simple carbs

The study is not as finished as the title may make it sound. The three major killers don't have one cause, but many.

However I agree in that sugar and carbs are a big factor, and one can go a long way avoiding them.

I thought it was protein https://www.livescience.com/43839-too-much-protein-help-canc...

Makes sense since excess protein is converted to glucose anyway. So ultimately, too much protein equals too much carbs, plus a bit too much of substances typical of mass farming.

Too much of any macronutrient causes a negative effect.

The amount of "too much" for fat is however greater than for the other two, and for most people it's difficult to overeat willingly with fat.

i'm also unsure how much is too much, but fat does affect insulin sensitivity

the issue would be to reduce fat consumption as much as humanly possible, while taking regular blood sugar measurement, only diabetics do this and it's already late by then.

https://www.ncbi.nlm.nih.gov/pubmed/15297079

The abstract of that study doesn't mention carbs. That's a very important detail. If you're eating a "normal" amount of carbs (like in the vast majority of studies of this type, even "low" can mean 25%), it is true that saturated fat makes it worse. But in other studies it has been shown to be the opposite with a fully ketogenic diet, i.e. when the body can't make glucose from carbs or protein and resorts to fat instead. Insulin _must_ be low for ketosis to happen. Insulin is also triggered by low sodium.

I cannot find a single study showing insuline resistance due to high fat consumption when consuming <5% of calories in carbs and <25% in protein.

it mentions insulin a lot, and you cannot metabolise carbs without it.

During ketosis there's barely any carbs to metabolize anyway. That's why I mention carbs at all: they cause the problem and saturated fat just makes the problem worse. A lot of these studies (esp the ones more than a decade old) show this correlation and makes the mistake to attribute the problem to fat.

Our ancestors only found carbs accompanied by lots of fiber. Fiber causes satiety. Carbs cause insulin secretion, which indirectly converts carbs to fat and puts the body in fat storage mode. Storing fat was an advantage to our ancestors because they couldn't ever store fat all year round. But nowadays 30% of calories in carbs is considered "normal" or even "low", but it's actually absurdly high considering the rest of the diet (low fiber, way too much fructose) and our activity.

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